diff --git a/bitbake/lib/bb/runqueue.py b/bitbake/lib/bb/runqueue.py
new file mode 100644
index 0000000..2b71eed
--- /dev/null
+++ b/bitbake/lib/bb/runqueue.py
@@ -0,0 +1,2195 @@
+#!/usr/bin/env python
+# ex:ts=4:sw=4:sts=4:et
+# -*- tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*-
+"""
+BitBake 'RunQueue' implementation
+
+Handles preparation and execution of a queue of tasks
+"""
+
+# Copyright (C) 2006-2007  Richard Purdie
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+import copy
+import os
+import sys
+import signal
+import stat
+import fcntl
+import errno
+import logging
+import re
+import bb
+from bb import msg, data, event
+from bb import monitordisk
+import subprocess
+
+try:
+    import cPickle as pickle
+except ImportError:
+    import pickle
+
+bblogger = logging.getLogger("BitBake")
+logger = logging.getLogger("BitBake.RunQueue")
+
+__find_md5__ = re.compile( r'(?i)(?<![a-z0-9])[a-f0-9]{32}(?![a-z0-9])' )
+
+class RunQueueStats:
+    """
+    Holds statistics on the tasks handled by the associated runQueue
+    """
+    def __init__(self, total):
+        self.completed = 0
+        self.skipped = 0
+        self.failed = 0
+        self.active = 0
+        self.total = total
+
+    def copy(self):
+        obj = self.__class__(self.total)
+        obj.__dict__.update(self.__dict__)
+        return obj
+
+    def taskFailed(self):
+        self.active = self.active - 1
+        self.failed = self.failed + 1
+
+    def taskCompleted(self, number = 1):
+        self.active = self.active - number
+        self.completed = self.completed + number
+
+    def taskSkipped(self, number = 1):
+        self.active = self.active + number
+        self.skipped = self.skipped + number
+
+    def taskActive(self):
+        self.active = self.active + 1
+
+# These values indicate the next step due to be run in the
+# runQueue state machine
+runQueuePrepare = 2
+runQueueSceneInit = 3
+runQueueSceneRun = 4
+runQueueRunInit = 5
+runQueueRunning = 6
+runQueueFailed = 7
+runQueueCleanUp = 8
+runQueueComplete = 9
+
+class RunQueueScheduler(object):
+    """
+    Control the order tasks are scheduled in.
+    """
+    name = "basic"
+
+    def __init__(self, runqueue, rqdata):
+        """
+        The default scheduler just returns the first buildable task (the
+        priority map is sorted by task number)
+        """
+        self.rq = runqueue
+        self.rqdata = rqdata
+        self.numTasks = len(self.rqdata.runq_fnid)
+
+        self.prio_map = []
+        self.prio_map.extend(range(self.numTasks))
+
+        self.buildable = []
+        self.stamps = {}
+        for taskid in xrange(self.numTasks):
+            fn = self.rqdata.taskData.fn_index[self.rqdata.runq_fnid[taskid]]
+            taskname = self.rqdata.runq_task[taskid]
+            self.stamps[taskid] = bb.build.stampfile(taskname, self.rqdata.dataCache, fn)
+            if self.rq.runq_buildable[taskid] == 1:
+                self.buildable.append(taskid)
+
+        self.rev_prio_map = None
+
+    def next_buildable_task(self):
+        """
+        Return the id of the first task we find that is buildable
+        """
+        self.buildable = [x for x in self.buildable if not self.rq.runq_running[x] == 1]
+        if not self.buildable:
+            return None
+        if len(self.buildable) == 1:
+            taskid = self.buildable[0]
+            stamp = self.stamps[taskid]
+            if stamp not in self.rq.build_stamps.itervalues():
+                return taskid
+
+        if not self.rev_prio_map:
+            self.rev_prio_map = range(self.numTasks)
+            for taskid in xrange(self.numTasks):
+                self.rev_prio_map[self.prio_map[taskid]] = taskid
+
+        best = None
+        bestprio = None
+        for taskid in self.buildable:
+            prio = self.rev_prio_map[taskid]
+            if bestprio is None or bestprio > prio:
+                stamp = self.stamps[taskid]
+                if stamp in self.rq.build_stamps.itervalues():
+                    continue
+                bestprio = prio
+                best = taskid
+
+        return best
+
+    def next(self):
+        """
+        Return the id of the task we should build next
+        """
+        if self.rq.stats.active < self.rq.number_tasks:
+            return self.next_buildable_task()
+
+    def newbuilable(self, task):
+        self.buildable.append(task)
+
+class RunQueueSchedulerSpeed(RunQueueScheduler):
+    """
+    A scheduler optimised for speed. The priority map is sorted by task weight,
+    heavier weighted tasks (tasks needed by the most other tasks) are run first.
+    """
+    name = "speed"
+
+    def __init__(self, runqueue, rqdata):
+        """
+        The priority map is sorted by task weight.
+        """
+        RunQueueScheduler.__init__(self, runqueue, rqdata)
+
+        sortweight = sorted(copy.deepcopy(self.rqdata.runq_weight))
+        copyweight = copy.deepcopy(self.rqdata.runq_weight)
+        self.prio_map = []
+
+        for weight in sortweight:
+            idx = copyweight.index(weight)
+            self.prio_map.append(idx)
+            copyweight[idx] = -1
+
+        self.prio_map.reverse()
+
+class RunQueueSchedulerCompletion(RunQueueSchedulerSpeed):
+    """
+    A scheduler optimised to complete .bb files are quickly as possible. The
+    priority map is sorted by task weight, but then reordered so once a given
+    .bb file starts to build, it's completed as quickly as possible. This works
+    well where disk space is at a premium and classes like OE's rm_work are in
+    force.
+    """
+    name = "completion"
+
+    def __init__(self, runqueue, rqdata):
+        RunQueueSchedulerSpeed.__init__(self, runqueue, rqdata)
+
+        #FIXME - whilst this groups all fnids together it does not reorder the
+        #fnid groups optimally.
+
+        basemap = copy.deepcopy(self.prio_map)
+        self.prio_map = []
+        while (len(basemap) > 0):
+            entry = basemap.pop(0)
+            self.prio_map.append(entry)
+            fnid = self.rqdata.runq_fnid[entry]
+            todel = []
+            for entry in basemap:
+                entry_fnid = self.rqdata.runq_fnid[entry]
+                if entry_fnid == fnid:
+                    todel.append(basemap.index(entry))
+                    self.prio_map.append(entry)
+            todel.reverse()
+            for idx in todel:
+                del basemap[idx]
+
+class RunQueueData:
+    """
+    BitBake Run Queue implementation
+    """
+    def __init__(self, rq, cooker, cfgData, dataCache, taskData, targets):
+        self.cooker = cooker
+        self.dataCache = dataCache
+        self.taskData = taskData
+        self.targets = targets
+        self.rq = rq
+        self.warn_multi_bb = False
+
+        self.stampwhitelist = cfgData.getVar("BB_STAMP_WHITELIST", True) or ""
+        self.multi_provider_whitelist = (cfgData.getVar("MULTI_PROVIDER_WHITELIST", True) or "").split()
+
+        self.reset()
+
+    def reset(self):
+        self.runq_fnid = []
+        self.runq_task = []
+        self.runq_depends = []
+        self.runq_revdeps = []
+        self.runq_hash = []
+
+    def runq_depends_names(self, ids):
+        import re
+        ret = []
+        for id in self.runq_depends[ids]:
+            nam = os.path.basename(self.get_user_idstring(id))
+            nam = re.sub("_[^,]*,", ",", nam)
+            ret.extend([nam])
+        return ret
+
+    def get_task_name(self, task):
+        return self.runq_task[task]
+
+    def get_task_file(self, task):
+        return self.taskData.fn_index[self.runq_fnid[task]]
+
+    def get_task_hash(self, task):
+        return self.runq_hash[task]
+
+    def get_user_idstring(self, task, task_name_suffix = ""):
+        fn = self.taskData.fn_index[self.runq_fnid[task]]
+        taskname = self.runq_task[task] + task_name_suffix
+        return "%s, %s" % (fn, taskname)
+
+    def get_task_id(self, fnid, taskname):
+        for listid in xrange(len(self.runq_fnid)):
+            if self.runq_fnid[listid] == fnid and self.runq_task[listid] == taskname:
+                return listid
+        return None
+
+    def circular_depchains_handler(self, tasks):
+        """
+        Some tasks aren't buildable, likely due to circular dependency issues.
+        Identify the circular dependencies and print them in a user readable format.
+        """
+        from copy import deepcopy
+
+        valid_chains = []
+        explored_deps = {}
+        msgs = []
+
+        def chain_reorder(chain):
+            """
+            Reorder a dependency chain so the lowest task id is first
+            """
+            lowest = 0
+            new_chain = []
+            for entry in xrange(len(chain)):
+                if chain[entry] < chain[lowest]:
+                    lowest = entry
+            new_chain.extend(chain[lowest:])
+            new_chain.extend(chain[:lowest])
+            return new_chain
+
+        def chain_compare_equal(chain1, chain2):
+            """
+            Compare two dependency chains and see if they're the same
+            """
+            if len(chain1) != len(chain2):
+                return False
+            for index in xrange(len(chain1)):
+                if chain1[index] != chain2[index]:
+                    return False
+            return True
+
+        def chain_array_contains(chain, chain_array):
+            """
+            Return True if chain_array contains chain
+            """
+            for ch in chain_array:
+                if chain_compare_equal(ch, chain):
+                    return True
+            return False
+
+        def find_chains(taskid, prev_chain):
+            prev_chain.append(taskid)
+            total_deps = []
+            total_deps.extend(self.runq_revdeps[taskid])
+            for revdep in self.runq_revdeps[taskid]:
+                if revdep in prev_chain:
+                    idx = prev_chain.index(revdep)
+                    # To prevent duplicates, reorder the chain to start with the lowest taskid
+                    # and search through an array of those we've already printed
+                    chain = prev_chain[idx:]
+                    new_chain = chain_reorder(chain)
+                    if not chain_array_contains(new_chain, valid_chains):
+                        valid_chains.append(new_chain)
+                        msgs.append("Dependency loop #%d found:\n" % len(valid_chains))
+                        for dep in new_chain:
+                            msgs.append("  Task %s (%s) (dependent Tasks %s)\n" % (dep, self.get_user_idstring(dep), self.runq_depends_names(dep)))
+                        msgs.append("\n")
+                    if len(valid_chains) > 10:
+                        msgs.append("Aborted dependency loops search after 10 matches.\n")
+                        return msgs
+                    continue
+                scan = False
+                if revdep not in explored_deps:
+                    scan = True
+                elif revdep in explored_deps[revdep]:
+                    scan = True
+                else:
+                    for dep in prev_chain:
+                        if dep in explored_deps[revdep]:
+                            scan = True
+                if scan:
+                    find_chains(revdep, copy.deepcopy(prev_chain))
+                for dep in explored_deps[revdep]:
+                    if dep not in total_deps:
+                        total_deps.append(dep)
+
+            explored_deps[taskid] = total_deps
+
+        for task in tasks:
+            find_chains(task, [])
+
+        return msgs
+
+    def calculate_task_weights(self, endpoints):
+        """
+        Calculate a number representing the "weight" of each task. Heavier weighted tasks
+        have more dependencies and hence should be executed sooner for maximum speed.
+
+        This function also sanity checks the task list finding tasks that are not
+        possible to execute due to circular dependencies.
+        """
+
+        numTasks = len(self.runq_fnid)
+        weight = []
+        deps_left = []
+        task_done = []
+
+        for listid in xrange(numTasks):
+            task_done.append(False)
+            weight.append(1)
+            deps_left.append(len(self.runq_revdeps[listid]))
+
+        for listid in endpoints:
+            weight[listid] = 10
+            task_done[listid] = True
+
+        while True:
+            next_points = []
+            for listid in endpoints:
+                for revdep in self.runq_depends[listid]:
+                    weight[revdep] = weight[revdep] + weight[listid]
+                    deps_left[revdep] = deps_left[revdep] - 1
+                    if deps_left[revdep] == 0:
+                        next_points.append(revdep)
+                        task_done[revdep] = True
+            endpoints = next_points
+            if len(next_points) == 0:
+                break
+
+        # Circular dependency sanity check
+        problem_tasks = []
+        for task in xrange(numTasks):
+            if task_done[task] is False or deps_left[task] != 0:
+                problem_tasks.append(task)
+                logger.debug(2, "Task %s (%s) is not buildable", task, self.get_user_idstring(task))
+                logger.debug(2, "(Complete marker was %s and the remaining dependency count was %s)\n", task_done[task], deps_left[task])
+
+        if problem_tasks:
+            message = "Unbuildable tasks were found.\n"
+            message = message + "These are usually caused by circular dependencies and any circular dependency chains found will be printed below. Increase the debug level to see a list of unbuildable tasks.\n\n"
+            message = message + "Identifying dependency loops (this may take a short while)...\n"
+            logger.error(message)
+
+            msgs = self.circular_depchains_handler(problem_tasks)
+
+            message = "\n"
+            for msg in msgs:
+                message = message + msg
+            bb.msg.fatal("RunQueue", message)
+
+        return weight
+
+    def prepare(self):
+        """
+        Turn a set of taskData into a RunQueue and compute data needed
+        to optimise the execution order.
+        """
+
+        runq_build = []
+        recursivetasks = {}
+        recursiveitasks = {}
+        recursivetasksselfref = set()
+
+        taskData = self.taskData
+
+        if len(taskData.tasks_name) == 0:
+            # Nothing to do
+            return 0
+
+        logger.info("Preparing RunQueue")
+
+        # Step A - Work out a list of tasks to run
+        #
+        # Taskdata gives us a list of possible providers for every build and run
+        # target ordered by priority. It also gives information on each of those
+        # providers.
+        #
+        # To create the actual list of tasks to execute we fix the list of
+        # providers and then resolve the dependencies into task IDs. This
+        # process is repeated for each type of dependency (tdepends, deptask,
+        # rdeptast, recrdeptask, idepends).
+
+        def add_build_dependencies(depids, tasknames, depends):
+            for depid in depids:
+                # Won't be in build_targets if ASSUME_PROVIDED
+                if depid not in taskData.build_targets:
+                    continue
+                depdata = taskData.build_targets[depid][0]
+                if depdata is None:
+                    continue
+                for taskname in tasknames:
+                    taskid = taskData.gettask_id_fromfnid(depdata, taskname)
+                    if taskid is not None:
+                        depends.add(taskid)
+
+        def add_runtime_dependencies(depids, tasknames, depends):
+            for depid in depids:
+                if depid not in taskData.run_targets:
+                    continue
+                depdata = taskData.run_targets[depid][0]
+                if depdata is None:
+                    continue
+                for taskname in tasknames:
+                    taskid = taskData.gettask_id_fromfnid(depdata, taskname)
+                    if taskid is not None:
+                        depends.add(taskid)
+
+        def add_resolved_dependencies(depids, tasknames, depends):
+            for depid in depids:
+                for taskname in tasknames:
+                    taskid = taskData.gettask_id_fromfnid(depid, taskname)
+                    if taskid is not None:
+                        depends.add(taskid)
+
+        for task in xrange(len(taskData.tasks_name)):
+            depends = set()
+            fnid = taskData.tasks_fnid[task]
+            fn = taskData.fn_index[fnid]
+            task_deps = self.dataCache.task_deps[fn]
+
+            #logger.debug(2, "Processing %s:%s", fn, taskData.tasks_name[task])
+
+            if fnid not in taskData.failed_fnids:
+
+                # Resolve task internal dependencies
+                #
+                # e.g. addtask before X after Y
+                depends = set(taskData.tasks_tdepends[task])
+
+                # Resolve 'deptask' dependencies
+                #
+                # e.g. do_sometask[deptask] = "do_someothertask"
+                # (makes sure sometask runs after someothertask of all DEPENDS)
+                if 'deptask' in task_deps and taskData.tasks_name[task] in task_deps['deptask']:
+                    tasknames = task_deps['deptask'][taskData.tasks_name[task]].split()
+                    add_build_dependencies(taskData.depids[fnid], tasknames, depends)
+
+                # Resolve 'rdeptask' dependencies
+                #
+                # e.g. do_sometask[rdeptask] = "do_someothertask"
+                # (makes sure sometask runs after someothertask of all RDEPENDS)
+                if 'rdeptask' in task_deps and taskData.tasks_name[task] in task_deps['rdeptask']:
+                    tasknames = task_deps['rdeptask'][taskData.tasks_name[task]].split()
+                    add_runtime_dependencies(taskData.rdepids[fnid], tasknames, depends)
+
+                # Resolve inter-task dependencies
+                #
+                # e.g. do_sometask[depends] = "targetname:do_someothertask"
+                # (makes sure sometask runs after targetname's someothertask)
+                idepends = taskData.tasks_idepends[task]
+                for (depid, idependtask) in idepends:
+                    if depid in taskData.build_targets and not depid in taskData.failed_deps:
+                        # Won't be in build_targets if ASSUME_PROVIDED
+                        depdata = taskData.build_targets[depid][0]
+                        if depdata is not None:
+                            taskid = taskData.gettask_id_fromfnid(depdata, idependtask)
+                            if taskid is None:
+                                bb.msg.fatal("RunQueue", "Task %s in %s depends upon non-existent task %s in %s" % (taskData.tasks_name[task], fn, idependtask, taskData.fn_index[depdata]))
+                            depends.add(taskid)
+                irdepends = taskData.tasks_irdepends[task]
+                for (depid, idependtask) in irdepends:
+                    if depid in taskData.run_targets:
+                        # Won't be in run_targets if ASSUME_PROVIDED
+                        depdata = taskData.run_targets[depid][0]
+                        if depdata is not None:
+                            taskid = taskData.gettask_id_fromfnid(depdata, idependtask)
+                            if taskid is None:
+                                bb.msg.fatal("RunQueue", "Task %s in %s rdepends upon non-existent task %s in %s" % (taskData.tasks_name[task], fn, idependtask, taskData.fn_index[depdata]))
+                            depends.add(taskid)
+
+                # Resolve recursive 'recrdeptask' dependencies (Part A)
+                #
+                # e.g. do_sometask[recrdeptask] = "do_someothertask"
+                # (makes sure sometask runs after someothertask of all DEPENDS, RDEPENDS and intertask dependencies, recursively)
+                # We cover the recursive part of the dependencies below
+                if 'recrdeptask' in task_deps and taskData.tasks_name[task] in task_deps['recrdeptask']:
+                    tasknames = task_deps['recrdeptask'][taskData.tasks_name[task]].split()
+                    recursivetasks[task] = tasknames
+                    add_build_dependencies(taskData.depids[fnid], tasknames, depends)
+                    add_runtime_dependencies(taskData.rdepids[fnid], tasknames, depends)
+                    if taskData.tasks_name[task] in tasknames:
+                        recursivetasksselfref.add(task)
+
+                    if 'recideptask' in task_deps and taskData.tasks_name[task] in task_deps['recideptask']:
+                        recursiveitasks[task] = []
+                        for t in task_deps['recideptask'][taskData.tasks_name[task]].split():
+                            newdep = taskData.gettask_id_fromfnid(fnid, t)
+                            recursiveitasks[task].append(newdep)
+
+            self.runq_fnid.append(taskData.tasks_fnid[task])
+            self.runq_task.append(taskData.tasks_name[task])
+            self.runq_depends.append(depends)
+            self.runq_revdeps.append(set())
+            self.runq_hash.append("")
+
+            runq_build.append(0)
+
+        # Resolve recursive 'recrdeptask' dependencies (Part B)
+        #
+        # e.g. do_sometask[recrdeptask] = "do_someothertask"
+        # (makes sure sometask runs after someothertask of all DEPENDS, RDEPENDS and intertask dependencies, recursively)
+        # We need to do this separately since we need all of self.runq_depends to be complete before this is processed
+        extradeps = {}
+        for task in recursivetasks:
+            extradeps[task] = set(self.runq_depends[task])
+            tasknames = recursivetasks[task]
+            seendeps = set()
+            seenfnid = []
+
+            def generate_recdeps(t):
+                newdeps = set()
+                add_resolved_dependencies([taskData.tasks_fnid[t]], tasknames, newdeps)
+                extradeps[task].update(newdeps)
+                seendeps.add(t)
+                newdeps.add(t)
+                for i in newdeps:
+                    for n in self.runq_depends[i]:
+                        if n not in seendeps:
+                            generate_recdeps(n)
+            generate_recdeps(task)
+
+            if task in recursiveitasks:
+                for dep in recursiveitasks[task]:
+                    generate_recdeps(dep)
+
+        # Remove circular references so that do_a[recrdeptask] = "do_a do_b" can work
+        for task in recursivetasks:
+            extradeps[task].difference_update(recursivetasksselfref)
+
+        for task in xrange(len(taskData.tasks_name)):
+            # Add in extra dependencies
+            if task in extradeps:
+                 self.runq_depends[task] = extradeps[task]
+            # Remove all self references
+            if task in self.runq_depends[task]:
+                logger.debug(2, "Task %s (%s %s) contains self reference! %s", task, taskData.fn_index[taskData.tasks_fnid[task]], taskData.tasks_name[task], self.runq_depends[task])
+                self.runq_depends[task].remove(task)
+
+        # Step B - Mark all active tasks
+        #
+        # Start with the tasks we were asked to run and mark all dependencies
+        # as active too. If the task is to be 'forced', clear its stamp. Once
+        # all active tasks are marked, prune the ones we don't need.
+
+        logger.verbose("Marking Active Tasks")
+
+        def mark_active(listid, depth):
+            """
+            Mark an item as active along with its depends
+            (calls itself recursively)
+            """
+
+            if runq_build[listid] == 1:
+                return
+
+            runq_build[listid] = 1
+
+            depends = self.runq_depends[listid]
+            for depend in depends:
+                mark_active(depend, depth+1)
+
+        self.target_pairs = []
+        for target in self.targets:
+            targetid = taskData.getbuild_id(target[0])
+
+            if targetid not in taskData.build_targets:
+                continue
+
+            if targetid in taskData.failed_deps:
+                continue
+
+            fnid = taskData.build_targets[targetid][0]
+            fn = taskData.fn_index[fnid]
+            self.target_pairs.append((fn, target[1]))
+
+            if fnid in taskData.failed_fnids:
+                continue
+
+            if target[1] not in taskData.tasks_lookup[fnid]:
+                import difflib
+                close_matches = difflib.get_close_matches(target[1], taskData.tasks_lookup[fnid], cutoff=0.7)
+                if close_matches:
+                    extra = ". Close matches:\n  %s" % "\n  ".join(close_matches)
+                else:
+                    extra = ""
+                bb.msg.fatal("RunQueue", "Task %s does not exist for target %s%s" % (target[1], target[0], extra))
+
+            listid = taskData.tasks_lookup[fnid][target[1]]
+
+            mark_active(listid, 1)
+
+        # Step C - Prune all inactive tasks
+        #
+        # Once all active tasks are marked, prune the ones we don't need.
+
+        maps = []
+        delcount = 0
+        for listid in xrange(len(self.runq_fnid)):
+            if runq_build[listid-delcount] == 1:
+                maps.append(listid-delcount)
+            else:
+                del self.runq_fnid[listid-delcount]
+                del self.runq_task[listid-delcount]
+                del self.runq_depends[listid-delcount]
+                del runq_build[listid-delcount]
+                del self.runq_revdeps[listid-delcount]
+                del self.runq_hash[listid-delcount]
+                delcount = delcount + 1
+                maps.append(-1)
+
+        #
+        # Step D - Sanity checks and computation
+        #
+
+        # Check to make sure we still have tasks to run
+        if len(self.runq_fnid) == 0:
+            if not taskData.abort:
+                bb.msg.fatal("RunQueue", "All buildable tasks have been run but the build is incomplete (--continue mode). Errors for the tasks that failed will have been printed above.")
+            else:
+                bb.msg.fatal("RunQueue", "No active tasks and not in --continue mode?! Please report this bug.")
+
+        logger.verbose("Pruned %s inactive tasks, %s left", delcount, len(self.runq_fnid))
+
+        # Remap the dependencies to account for the deleted tasks
+        # Check we didn't delete a task we depend on
+        for listid in xrange(len(self.runq_fnid)):
+            newdeps = []
+            origdeps = self.runq_depends[listid]
+            for origdep in origdeps:
+                if maps[origdep] == -1:
+                    bb.msg.fatal("RunQueue", "Invalid mapping - Should never happen!")
+                newdeps.append(maps[origdep])
+            self.runq_depends[listid] = set(newdeps)
+
+        logger.verbose("Assign Weightings")
+
+        # Generate a list of reverse dependencies to ease future calculations
+        for listid in xrange(len(self.runq_fnid)):
+            for dep in self.runq_depends[listid]:
+                self.runq_revdeps[dep].add(listid)
+
+        # Identify tasks at the end of dependency chains
+        # Error on circular dependency loops (length two)
+        endpoints = []
+        for listid in xrange(len(self.runq_fnid)):
+            revdeps = self.runq_revdeps[listid]
+            if len(revdeps) == 0:
+                endpoints.append(listid)
+            for dep in revdeps:
+                if dep in self.runq_depends[listid]:
+                    #self.dump_data(taskData)
+                    bb.msg.fatal("RunQueue", "Task %s (%s) has circular dependency on %s (%s)" % (taskData.fn_index[self.runq_fnid[dep]], self.runq_task[dep], taskData.fn_index[self.runq_fnid[listid]], self.runq_task[listid]))
+
+        logger.verbose("Compute totals (have %s endpoint(s))", len(endpoints))
+
+        # Calculate task weights
+        # Check of higher length circular dependencies
+        self.runq_weight = self.calculate_task_weights(endpoints)
+
+        # Sanity Check - Check for multiple tasks building the same provider
+        prov_list = {}
+        seen_fn = []
+        for task in xrange(len(self.runq_fnid)):
+            fn = taskData.fn_index[self.runq_fnid[task]]
+            if fn in seen_fn:
+                continue
+            seen_fn.append(fn)
+            for prov in self.dataCache.fn_provides[fn]:
+                if prov not in prov_list:
+                    prov_list[prov] = [fn]
+                elif fn not in prov_list[prov]:
+                    prov_list[prov].append(fn)
+        for prov in prov_list:
+            if len(prov_list[prov]) > 1 and prov not in self.multi_provider_whitelist:
+                seen_pn = []
+                # If two versions of the same PN are being built its fatal, we don't support it.
+                for fn in prov_list[prov]:
+                    pn = self.dataCache.pkg_fn[fn]
+                    if pn not in seen_pn:
+                        seen_pn.append(pn)
+                    else:
+                        bb.fatal("Multiple versions of %s are due to be built (%s). Only one version of a given PN should be built in any given build. You likely need to set PREFERRED_VERSION_%s to select the correct version or don't depend on multiple versions." % (pn, " ".join(prov_list[prov]), pn))
+                msg = "Multiple .bb files are due to be built which each provide %s (%s)." % (prov, " ".join(prov_list[prov]))
+                if self.warn_multi_bb:
+                    logger.warn(msg)
+                else:
+                    msg += "\n This usually means one provides something the other doesn't and should."
+                    logger.error(msg)
+
+        # Create a whitelist usable by the stamp checks
+        stampfnwhitelist = []
+        for entry in self.stampwhitelist.split():
+            entryid = self.taskData.getbuild_id(entry)
+            if entryid not in self.taskData.build_targets:
+                continue
+            fnid = self.taskData.build_targets[entryid][0]
+            fn = self.taskData.fn_index[fnid]
+            stampfnwhitelist.append(fn)
+        self.stampfnwhitelist = stampfnwhitelist
+
+        # Iterate over the task list looking for tasks with a 'setscene' function
+        self.runq_setscene = []
+        if not self.cooker.configuration.nosetscene:
+            for task in range(len(self.runq_fnid)):
+                setscene = taskData.gettask_id(self.taskData.fn_index[self.runq_fnid[task]], self.runq_task[task] + "_setscene", False)
+                if not setscene:
+                    continue
+                self.runq_setscene.append(task)
+
+        def invalidate_task(fn, taskname, error_nostamp):
+            taskdep = self.dataCache.task_deps[fn]
+            fnid = self.taskData.getfn_id(fn)
+            if taskname not in taskData.tasks_lookup[fnid]:
+                logger.warn("Task %s does not exist, invalidating this task will have no effect" % taskname)
+            if 'nostamp' in taskdep and taskname in taskdep['nostamp']:
+                if error_nostamp:
+                    bb.fatal("Task %s is marked nostamp, cannot invalidate this task" % taskname)
+                else:
+                    bb.debug(1, "Task %s is marked nostamp, cannot invalidate this task" % taskname)
+            else:
+                logger.verbose("Invalidate task %s, %s", taskname, fn)
+                bb.parse.siggen.invalidate_task(taskname, self.dataCache, fn)
+
+        # Invalidate task if force mode active
+        if self.cooker.configuration.force:
+            for (fn, target) in self.target_pairs:
+                invalidate_task(fn, target, False)
+
+        # Invalidate task if invalidate mode active
+        if self.cooker.configuration.invalidate_stamp:
+            for (fn, target) in self.target_pairs:
+                for st in self.cooker.configuration.invalidate_stamp.split(','):
+                    if not st.startswith("do_"):
+                        st = "do_%s" % st
+                    invalidate_task(fn, st, True)
+
+        # Iterate over the task list and call into the siggen code
+        dealtwith = set()
+        todeal = set(range(len(self.runq_fnid)))
+        while len(todeal) > 0:
+            for task in todeal.copy():
+                if len(self.runq_depends[task] - dealtwith) == 0:
+                    dealtwith.add(task)
+                    todeal.remove(task)
+                    procdep = []
+                    for dep in self.runq_depends[task]:
+                        procdep.append(self.taskData.fn_index[self.runq_fnid[dep]] + "." + self.runq_task[dep])
+                    self.runq_hash[task] = bb.parse.siggen.get_taskhash(self.taskData.fn_index[self.runq_fnid[task]], self.runq_task[task], procdep, self.dataCache)
+
+        return len(self.runq_fnid)
+
+    def dump_data(self, taskQueue):
+        """
+        Dump some debug information on the internal data structures
+        """
+        logger.debug(3, "run_tasks:")
+        for task in xrange(len(self.rqdata.runq_task)):
+            logger.debug(3, " (%s)%s - %s: %s   Deps %s RevDeps %s", task,
+                         taskQueue.fn_index[self.rqdata.runq_fnid[task]],
+                         self.rqdata.runq_task[task],
+                         self.rqdata.runq_weight[task],
+                         self.rqdata.runq_depends[task],
+                         self.rqdata.runq_revdeps[task])
+
+        logger.debug(3, "sorted_tasks:")
+        for task1 in xrange(len(self.rqdata.runq_task)):
+            if task1 in self.prio_map:
+                task = self.prio_map[task1]
+                logger.debug(3, " (%s)%s - %s: %s   Deps %s RevDeps %s", task,
+                           taskQueue.fn_index[self.rqdata.runq_fnid[task]],
+                           self.rqdata.runq_task[task],
+                           self.rqdata.runq_weight[task],
+                           self.rqdata.runq_depends[task],
+                           self.rqdata.runq_revdeps[task])
+
+class RunQueue:
+    def __init__(self, cooker, cfgData, dataCache, taskData, targets):
+
+        self.cooker = cooker
+        self.cfgData = cfgData
+        self.rqdata = RunQueueData(self, cooker, cfgData, dataCache, taskData, targets)
+
+        self.stamppolicy = cfgData.getVar("BB_STAMP_POLICY", True) or "perfile"
+        self.hashvalidate = cfgData.getVar("BB_HASHCHECK_FUNCTION", True) or None
+        self.setsceneverify = cfgData.getVar("BB_SETSCENE_VERIFY_FUNCTION", True) or None
+        self.depvalidate = cfgData.getVar("BB_SETSCENE_DEPVALID", True) or None
+
+        self.state = runQueuePrepare
+
+        # For disk space monitor
+        self.dm = monitordisk.diskMonitor(cfgData)
+
+        self.rqexe = None
+        self.worker = None
+        self.workerpipe = None
+        self.fakeworker = None
+        self.fakeworkerpipe = None
+
+    def _start_worker(self, fakeroot = False, rqexec = None):
+        logger.debug(1, "Starting bitbake-worker")
+        magic = "decafbad"
+        if self.cooker.configuration.profile:
+            magic = "decafbadbad"
+        if fakeroot:
+            fakerootcmd = self.cfgData.getVar("FAKEROOTCMD", True)
+            fakerootenv = (self.cfgData.getVar("FAKEROOTBASEENV", True) or "").split()
+            env = os.environ.copy()
+            for key, value in (var.split('=') for var in fakerootenv):
+                env[key] = value
+            worker = subprocess.Popen([fakerootcmd, "bitbake-worker", magic], stdout=subprocess.PIPE, stdin=subprocess.PIPE, env=env)
+        else:
+            worker = subprocess.Popen(["bitbake-worker", magic], stdout=subprocess.PIPE, stdin=subprocess.PIPE)
+        bb.utils.nonblockingfd(worker.stdout)
+        workerpipe = runQueuePipe(worker.stdout, None, self.cfgData, self, rqexec)
+
+        workerdata = {
+            "taskdeps" : self.rqdata.dataCache.task_deps,
+            "fakerootenv" : self.rqdata.dataCache.fakerootenv,
+            "fakerootdirs" : self.rqdata.dataCache.fakerootdirs,
+            "fakerootnoenv" : self.rqdata.dataCache.fakerootnoenv,
+            "sigdata" : bb.parse.siggen.get_taskdata(),
+            "runq_hash" : self.rqdata.runq_hash,
+            "logdefaultdebug" : bb.msg.loggerDefaultDebugLevel,
+            "logdefaultverbose" : bb.msg.loggerDefaultVerbose,
+            "logdefaultverboselogs" : bb.msg.loggerVerboseLogs,
+            "logdefaultdomain" : bb.msg.loggerDefaultDomains,
+            "prhost" : self.cooker.prhost,
+            "buildname" : self.cfgData.getVar("BUILDNAME", True),
+            "date" : self.cfgData.getVar("DATE", True),
+            "time" : self.cfgData.getVar("TIME", True),
+        }
+
+        worker.stdin.write("<cookerconfig>" + pickle.dumps(self.cooker.configuration) + "</cookerconfig>")
+        worker.stdin.write("<workerdata>" + pickle.dumps(workerdata) + "</workerdata>")
+        worker.stdin.flush()
+
+        return worker, workerpipe
+
+    def _teardown_worker(self, worker, workerpipe):
+        if not worker:
+            return
+        logger.debug(1, "Teardown for bitbake-worker")
+        try:
+           worker.stdin.write("<quit></quit>")
+           worker.stdin.flush()
+        except IOError:
+           pass
+        while worker.returncode is None:
+            workerpipe.read()
+            worker.poll()
+        while workerpipe.read():
+            continue
+        workerpipe.close()
+
+    def start_worker(self):
+        if self.worker:
+            self.teardown_workers()
+        self.teardown = False
+        self.worker, self.workerpipe = self._start_worker()
+
+    def start_fakeworker(self, rqexec):
+        if not self.fakeworker:
+            self.fakeworker, self.fakeworkerpipe = self._start_worker(True, rqexec)
+
+    def teardown_workers(self):
+        self.teardown = True
+        self._teardown_worker(self.worker, self.workerpipe)
+        self.worker = None
+        self.workerpipe = None
+        self._teardown_worker(self.fakeworker, self.fakeworkerpipe)
+        self.fakeworker = None
+        self.fakeworkerpipe = None
+
+    def read_workers(self):
+        self.workerpipe.read()
+        if self.fakeworkerpipe:
+            self.fakeworkerpipe.read()
+
+    def active_fds(self):
+        fds = []
+        if self.workerpipe:
+            fds.append(self.workerpipe.input)
+        if self.fakeworkerpipe:
+            fds.append(self.fakeworkerpipe.input)
+        return fds
+
+    def check_stamp_task(self, task, taskname = None, recurse = False, cache = None):
+        def get_timestamp(f):
+            try:
+                if not os.access(f, os.F_OK):
+                    return None
+                return os.stat(f)[stat.ST_MTIME]
+            except:
+                return None
+
+        if self.stamppolicy == "perfile":
+            fulldeptree = False
+        else:
+            fulldeptree = True
+            stampwhitelist = []
+            if self.stamppolicy == "whitelist":
+                stampwhitelist = self.rqdata.stampfnwhitelist
+
+        fn = self.rqdata.taskData.fn_index[self.rqdata.runq_fnid[task]]
+        if taskname is None:
+            taskname = self.rqdata.runq_task[task]
+
+        stampfile = bb.build.stampfile(taskname, self.rqdata.dataCache, fn)
+
+        # If the stamp is missing, it's not current
+        if not os.access(stampfile, os.F_OK):
+            logger.debug(2, "Stampfile %s not available", stampfile)
+            return False
+        # If it's a 'nostamp' task, it's not current
+        taskdep = self.rqdata.dataCache.task_deps[fn]
+        if 'nostamp' in taskdep and taskname in taskdep['nostamp']:
+            logger.debug(2, "%s.%s is nostamp\n", fn, taskname)
+            return False
+
+        if taskname != "do_setscene" and taskname.endswith("_setscene"):
+            return True
+
+        if cache is None:
+            cache = {}
+
+        iscurrent = True
+        t1 = get_timestamp(stampfile)
+        for dep in self.rqdata.runq_depends[task]:
+            if iscurrent:
+                fn2 = self.rqdata.taskData.fn_index[self.rqdata.runq_fnid[dep]]
+                taskname2 = self.rqdata.runq_task[dep]
+                stampfile2 = bb.build.stampfile(taskname2, self.rqdata.dataCache, fn2)
+                stampfile3 = bb.build.stampfile(taskname2 + "_setscene", self.rqdata.dataCache, fn2)
+                t2 = get_timestamp(stampfile2)
+                t3 = get_timestamp(stampfile3)
+                if t3 and t3 > t2:
+                   continue
+                if fn == fn2 or (fulldeptree and fn2 not in stampwhitelist):
+                    if not t2:
+                        logger.debug(2, 'Stampfile %s does not exist', stampfile2)
+                        iscurrent = False
+                    if t1 < t2:
+                        logger.debug(2, 'Stampfile %s < %s', stampfile, stampfile2)
+                        iscurrent = False
+                    if recurse and iscurrent:
+                        if dep in cache:
+                            iscurrent = cache[dep]
+                            if not iscurrent:
+                                logger.debug(2, 'Stampfile for dependency %s:%s invalid (cached)' % (fn2, taskname2))
+                        else:
+                            iscurrent = self.check_stamp_task(dep, recurse=True, cache=cache)
+                            cache[dep] = iscurrent
+        if recurse:
+            cache[task] = iscurrent
+        return iscurrent
+
+    def _execute_runqueue(self):
+        """
+        Run the tasks in a queue prepared by rqdata.prepare()
+        Upon failure, optionally try to recover the build using any alternate providers
+        (if the abort on failure configuration option isn't set)
+        """
+
+        retval = True
+
+        if self.state is runQueuePrepare:
+            self.rqexe = RunQueueExecuteDummy(self)
+            if self.rqdata.prepare() == 0:
+                self.state = runQueueComplete
+            else:
+                self.state = runQueueSceneInit
+
+                # we are ready to run, see if any UI client needs the dependency info
+                if bb.cooker.CookerFeatures.SEND_DEPENDS_TREE in self.cooker.featureset:
+                    depgraph = self.cooker.buildDependTree(self, self.rqdata.taskData)
+                    bb.event.fire(bb.event.DepTreeGenerated(depgraph), self.cooker.data)
+
+        if self.state is runQueueSceneInit:
+            dump = self.cooker.configuration.dump_signatures
+            if dump:
+                if 'printdiff' in dump:
+                    invalidtasks = self.print_diffscenetasks()
+                self.dump_signatures(dump)
+                if 'printdiff' in dump:
+                    self.write_diffscenetasks(invalidtasks)
+                self.state = runQueueComplete
+            else:
+                self.start_worker()
+                self.rqexe = RunQueueExecuteScenequeue(self)
+
+        if self.state in [runQueueSceneRun, runQueueRunning, runQueueCleanUp]:
+            self.dm.check(self)
+
+        if self.state is runQueueSceneRun:
+            retval = self.rqexe.execute()
+
+        if self.state is runQueueRunInit:
+            logger.info("Executing RunQueue Tasks")
+            self.rqexe = RunQueueExecuteTasks(self)
+            self.state = runQueueRunning
+
+        if self.state is runQueueRunning:
+            retval = self.rqexe.execute()
+
+        if self.state is runQueueCleanUp:
+            retval = self.rqexe.finish()
+
+        if (self.state is runQueueComplete or self.state is runQueueFailed) and self.rqexe:
+            self.teardown_workers()
+            if self.rqexe.stats.failed:
+                logger.info("Tasks Summary: Attempted %d tasks of which %d didn't need to be rerun and %d failed.", self.rqexe.stats.completed + self.rqexe.stats.failed, self.rqexe.stats.skipped, self.rqexe.stats.failed)
+            else:
+                # Let's avoid the word "failed" if nothing actually did
+                logger.info("Tasks Summary: Attempted %d tasks of which %d didn't need to be rerun and all succeeded.", self.rqexe.stats.completed, self.rqexe.stats.skipped)
+
+        if self.state is runQueueFailed:
+            if not self.rqdata.taskData.tryaltconfigs:
+                raise bb.runqueue.TaskFailure(self.rqexe.failed_fnids)
+            for fnid in self.rqexe.failed_fnids:
+                self.rqdata.taskData.fail_fnid(fnid)
+            self.rqdata.reset()
+
+        if self.state is runQueueComplete:
+            # All done
+            return False
+
+        # Loop
+        return retval
+
+    def execute_runqueue(self):
+        # Catch unexpected exceptions and ensure we exit when an error occurs, not loop.
+        try:
+            return self._execute_runqueue()
+        except bb.runqueue.TaskFailure:
+            raise
+        except SystemExit:
+            raise
+        except bb.BBHandledException:
+            try:
+                self.teardown_workers()
+            except:
+                pass
+            self.state = runQueueComplete
+            raise
+        except:
+            logger.error("An uncaught exception occured in runqueue, please see the failure below:")
+            try:
+                self.teardown_workers()
+            except:
+                pass
+            self.state = runQueueComplete
+            raise
+
+    def finish_runqueue(self, now = False):
+        if not self.rqexe:
+            self.state = runQueueComplete
+            return
+
+        if now:
+            self.rqexe.finish_now()
+        else:
+            self.rqexe.finish()
+
+    def dump_signatures(self, options):
+        done = set()
+        bb.note("Reparsing files to collect dependency data")
+        for task in range(len(self.rqdata.runq_fnid)):
+            if self.rqdata.runq_fnid[task] not in done:
+                fn = self.rqdata.taskData.fn_index[self.rqdata.runq_fnid[task]]
+                the_data = bb.cache.Cache.loadDataFull(fn, self.cooker.collection.get_file_appends(fn), self.cooker.data)
+                done.add(self.rqdata.runq_fnid[task])
+
+        bb.parse.siggen.dump_sigs(self.rqdata.dataCache, options)
+
+        return
+
+    def print_diffscenetasks(self):
+
+        valid = []
+        sq_hash = []
+        sq_hashfn = []
+        sq_fn = []
+        sq_taskname = []
+        sq_task = []
+        noexec = []
+        stamppresent = []
+        valid_new = set()
+
+        for task in xrange(len(self.rqdata.runq_fnid)):
+            fn = self.rqdata.taskData.fn_index[self.rqdata.runq_fnid[task]]
+            taskname = self.rqdata.runq_task[task]
+            taskdep = self.rqdata.dataCache.task_deps[fn]
+
+            if 'noexec' in taskdep and taskname in taskdep['noexec']:
+                noexec.append(task)
+                continue
+
+            sq_fn.append(fn)
+            sq_hashfn.append(self.rqdata.dataCache.hashfn[fn])
+            sq_hash.append(self.rqdata.runq_hash[task])
+            sq_taskname.append(taskname)
+            sq_task.append(task)
+        locs = { "sq_fn" : sq_fn, "sq_task" : sq_taskname, "sq_hash" : sq_hash, "sq_hashfn" : sq_hashfn, "d" : self.cooker.expanded_data }
+        try:
+            call = self.hashvalidate + "(sq_fn, sq_task, sq_hash, sq_hashfn, d, siginfo=True)"
+            valid = bb.utils.better_eval(call, locs)
+        # Handle version with no siginfo parameter
+        except TypeError:
+            call = self.hashvalidate + "(sq_fn, sq_task, sq_hash, sq_hashfn, d)"
+            valid = bb.utils.better_eval(call, locs)
+        for v in valid:
+            valid_new.add(sq_task[v])
+
+        # Tasks which are both setscene and noexec never care about dependencies
+        # We therefore find tasks which are setscene and noexec and mark their
+        # unique dependencies as valid.
+        for task in noexec:
+            if task not in self.rqdata.runq_setscene:
+                continue
+            for dep in self.rqdata.runq_depends[task]:
+                hasnoexecparents = True
+                for dep2 in self.rqdata.runq_revdeps[dep]:
+                    if dep2 in self.rqdata.runq_setscene and dep2 in noexec:
+                        continue
+                    hasnoexecparents = False
+                    break
+                if hasnoexecparents:
+                    valid_new.add(dep)
+
+        invalidtasks = set()
+        for task in xrange(len(self.rqdata.runq_fnid)):
+            if task not in valid_new and task not in noexec:
+                invalidtasks.add(task)
+
+        found = set()
+        processed = set()
+        for task in invalidtasks:
+            toprocess = set([task])
+            while toprocess:
+                next = set()
+                for t in toprocess:
+                    for dep in self.rqdata.runq_depends[t]:
+                        if dep in invalidtasks:
+                            found.add(task)
+                        if dep not in processed:
+                            processed.add(dep)
+                            next.add(dep)
+                toprocess = next
+                if task in found:
+                    toprocess = set()
+
+        tasklist = []
+        for task in invalidtasks.difference(found):
+            tasklist.append(self.rqdata.get_user_idstring(task))
+
+        if tasklist:
+            bb.plain("The differences between the current build and any cached tasks start at the following tasks:\n" + "\n".join(tasklist))
+
+        return invalidtasks.difference(found)
+
+    def write_diffscenetasks(self, invalidtasks):
+
+        # Define recursion callback
+        def recursecb(key, hash1, hash2):
+            hashes = [hash1, hash2]
+            hashfiles = bb.siggen.find_siginfo(key, None, hashes, self.cfgData)
+
+            recout = []
+            if len(hashfiles) == 2:
+                out2 = bb.siggen.compare_sigfiles(hashfiles[hash1], hashfiles[hash2], recursecb)
+                recout.extend(list('  ' + l for l in out2))
+            else:
+                recout.append("Unable to find matching sigdata for %s with hashes %s or %s" % (key, hash1, hash2))
+
+            return recout
+
+
+        for task in invalidtasks:
+            fn = self.rqdata.taskData.fn_index[self.rqdata.runq_fnid[task]]
+            pn = self.rqdata.dataCache.pkg_fn[fn]
+            taskname = self.rqdata.runq_task[task]
+            h = self.rqdata.runq_hash[task]
+            matches = bb.siggen.find_siginfo(pn, taskname, [], self.cfgData)
+            match = None
+            for m in matches:
+                if h in m:
+                    match = m
+            if match is None:
+                bb.fatal("Can't find a task we're supposed to have written out? (hash: %s)?" % h)
+            matches = {k : v for k, v in matches.iteritems() if h not in k}
+            if matches:
+                latestmatch = sorted(matches.keys(), key=lambda f: matches[f])[-1]
+                prevh = __find_md5__.search(latestmatch).group(0)
+                output = bb.siggen.compare_sigfiles(latestmatch, match, recursecb)
+                bb.plain("\nTask %s:%s couldn't be used from the cache because:\n  We need hash %s, closest matching task was %s\n  " % (pn, taskname, h, prevh) + '\n  '.join(output))
+
+class RunQueueExecute:
+
+    def __init__(self, rq):
+        self.rq = rq
+        self.cooker = rq.cooker
+        self.cfgData = rq.cfgData
+        self.rqdata = rq.rqdata
+
+        self.number_tasks = int(self.cfgData.getVar("BB_NUMBER_THREADS", True) or 1)
+        self.scheduler = self.cfgData.getVar("BB_SCHEDULER", True) or "speed"
+
+        self.runq_buildable = []
+        self.runq_running = []
+        self.runq_complete = []
+
+        self.build_stamps = {}
+        self.build_stamps2 = []
+        self.failed_fnids = []
+
+        self.stampcache = {}
+
+        rq.workerpipe.setrunqueueexec(self)
+        if rq.fakeworkerpipe:
+            rq.fakeworkerpipe.setrunqueueexec(self)
+
+        if self.number_tasks <= 0:
+             bb.fatal("Invalid BB_NUMBER_THREADS %s" % self.number_tasks)
+
+    def runqueue_process_waitpid(self, task, status):
+
+        # self.build_stamps[pid] may not exist when use shared work directory.
+        if task in self.build_stamps:
+            self.build_stamps2.remove(self.build_stamps[task])
+            del self.build_stamps[task]
+
+        if status != 0:
+            self.task_fail(task, status)
+        else:
+            self.task_complete(task)
+        return True
+
+    def finish_now(self):
+
+        for worker in [self.rq.worker, self.rq.fakeworker]:
+            if not worker:
+                continue
+            try:
+                worker.stdin.write("<finishnow></finishnow>")
+                worker.stdin.flush()
+            except IOError:
+                # worker must have died?
+                pass
+
+        if len(self.failed_fnids) != 0:
+            self.rq.state = runQueueFailed
+            return
+
+        self.rq.state = runQueueComplete
+        return
+
+    def finish(self):
+        self.rq.state = runQueueCleanUp
+
+        if self.stats.active > 0:
+            bb.event.fire(runQueueExitWait(self.stats.active), self.cfgData)
+            self.rq.read_workers()
+            return self.rq.active_fds()
+
+        if len(self.failed_fnids) != 0:
+            self.rq.state = runQueueFailed
+            return True
+
+        self.rq.state = runQueueComplete
+        return True
+
+    def check_dependencies(self, task, taskdeps, setscene = False):
+        if not self.rq.depvalidate:
+            return False
+
+        taskdata = {}
+        taskdeps.add(task)
+        for dep in taskdeps:
+            if setscene:
+                depid = self.rqdata.runq_setscene[dep]
+            else:
+                depid = dep
+            fn = self.rqdata.taskData.fn_index[self.rqdata.runq_fnid[depid]]
+            pn = self.rqdata.dataCache.pkg_fn[fn]
+            taskname = self.rqdata.runq_task[depid]
+            taskdata[dep] = [pn, taskname, fn]
+        call = self.rq.depvalidate + "(task, taskdata, notneeded, d)"
+        locs = { "task" : task, "taskdata" : taskdata, "notneeded" : self.scenequeue_notneeded, "d" : self.cooker.expanded_data }
+        valid = bb.utils.better_eval(call, locs)
+        return valid
+
+class RunQueueExecuteDummy(RunQueueExecute):
+    def __init__(self, rq):
+        self.rq = rq
+        self.stats = RunQueueStats(0)
+
+    def finish(self):
+        self.rq.state = runQueueComplete
+        return
+
+class RunQueueExecuteTasks(RunQueueExecute):
+    def __init__(self, rq):
+        RunQueueExecute.__init__(self, rq)
+
+        self.stats = RunQueueStats(len(self.rqdata.runq_fnid))
+
+        self.stampcache = {}
+
+        initial_covered = self.rq.scenequeue_covered.copy()
+
+        # Mark initial buildable tasks
+        for task in xrange(self.stats.total):
+            self.runq_running.append(0)
+            self.runq_complete.append(0)
+            if len(self.rqdata.runq_depends[task]) == 0:
+                self.runq_buildable.append(1)
+            else:
+                self.runq_buildable.append(0)
+            if len(self.rqdata.runq_revdeps[task]) > 0 and self.rqdata.runq_revdeps[task].issubset(self.rq.scenequeue_covered) and task not in self.rq.scenequeue_notcovered:
+                self.rq.scenequeue_covered.add(task)
+
+        found = True
+        while found:
+            found = False
+            for task in xrange(self.stats.total):
+                if task in self.rq.scenequeue_covered:
+                    continue
+                logger.debug(1, 'Considering %s (%s): %s' % (task, self.rqdata.get_user_idstring(task), str(self.rqdata.runq_revdeps[task])))
+
+                if len(self.rqdata.runq_revdeps[task]) > 0 and self.rqdata.runq_revdeps[task].issubset(self.rq.scenequeue_covered) and task not in self.rq.scenequeue_notcovered:
+                    found = True
+                    self.rq.scenequeue_covered.add(task)
+
+        logger.debug(1, 'Skip list (pre setsceneverify) %s', sorted(self.rq.scenequeue_covered))
+
+        # Allow the metadata to elect for setscene tasks to run anyway
+        covered_remove = set()
+        if self.rq.setsceneverify:
+            invalidtasks = []
+            for task in xrange(len(self.rqdata.runq_task)):
+                fn = self.rqdata.taskData.fn_index[self.rqdata.runq_fnid[task]]
+                taskname = self.rqdata.runq_task[task]
+                taskdep = self.rqdata.dataCache.task_deps[fn]
+
+                if 'noexec' in taskdep and taskname in taskdep['noexec']:
+                    continue
+                if self.rq.check_stamp_task(task, taskname + "_setscene", cache=self.stampcache):
+                    logger.debug(2, 'Setscene stamp current for task %s(%s)', task, self.rqdata.get_user_idstring(task))
+                    continue
+                if self.rq.check_stamp_task(task, taskname, recurse = True, cache=self.stampcache):
+                    logger.debug(2, 'Normal stamp current for task %s(%s)', task, self.rqdata.get_user_idstring(task))
+                    continue
+                invalidtasks.append(task)
+
+            call = self.rq.setsceneverify + "(covered, tasknames, fnids, fns, d, invalidtasks=invalidtasks)"
+            call2 = self.rq.setsceneverify + "(covered, tasknames, fnids, fns, d)"
+            locs = { "covered" : self.rq.scenequeue_covered, "tasknames" : self.rqdata.runq_task, "fnids" : self.rqdata.runq_fnid, "fns" : self.rqdata.taskData.fn_index, "d" : self.cooker.expanded_data, "invalidtasks" : invalidtasks }
+            # Backwards compatibility with older versions without invalidtasks
+            try:
+                covered_remove = bb.utils.better_eval(call, locs)
+            except TypeError:
+                covered_remove = bb.utils.better_eval(call2, locs)
+
+        def removecoveredtask(task):
+            fn = self.rqdata.taskData.fn_index[self.rqdata.runq_fnid[task]]
+            taskname = self.rqdata.runq_task[task] + '_setscene'
+            bb.build.del_stamp(taskname, self.rqdata.dataCache, fn)
+            self.rq.scenequeue_covered.remove(task)
+
+        toremove = covered_remove
+        for task in toremove:
+            logger.debug(1, 'Not skipping task %s due to setsceneverify', task)
+        while toremove:
+            covered_remove = []
+            for task in toremove:
+                removecoveredtask(task)
+                for deptask in self.rqdata.runq_depends[task]:
+                    if deptask not in self.rq.scenequeue_covered:
+                        continue
+                    if deptask in toremove or deptask in covered_remove or deptask in initial_covered:
+                        continue
+                    logger.debug(1, 'Task %s depends on task %s so not skipping' % (task, deptask))
+                    covered_remove.append(deptask)
+            toremove = covered_remove
+
+        logger.debug(1, 'Full skip list %s', self.rq.scenequeue_covered)
+
+        event.fire(bb.event.StampUpdate(self.rqdata.target_pairs, self.rqdata.dataCache.stamp), self.cfgData)
+
+        schedulers = self.get_schedulers()
+        for scheduler in schedulers:
+            if self.scheduler == scheduler.name:
+                self.sched = scheduler(self, self.rqdata)
+                logger.debug(1, "Using runqueue scheduler '%s'", scheduler.name)
+                break
+        else:
+            bb.fatal("Invalid scheduler '%s'.  Available schedulers: %s" %
+                     (self.scheduler, ", ".join(obj.name for obj in schedulers)))
+
+    def get_schedulers(self):
+        schedulers = set(obj for obj in globals().values()
+                             if type(obj) is type and
+                                issubclass(obj, RunQueueScheduler))
+
+        user_schedulers = self.cfgData.getVar("BB_SCHEDULERS", True)
+        if user_schedulers:
+            for sched in user_schedulers.split():
+                if not "." in sched:
+                    bb.note("Ignoring scheduler '%s' from BB_SCHEDULERS: not an import" % sched)
+                    continue
+
+                modname, name = sched.rsplit(".", 1)
+                try:
+                    module = __import__(modname, fromlist=(name,))
+                except ImportError as exc:
+                    logger.critical("Unable to import scheduler '%s' from '%s': %s" % (name, modname, exc))
+                    raise SystemExit(1)
+                else:
+                    schedulers.add(getattr(module, name))
+        return schedulers
+
+    def setbuildable(self, task):
+        self.runq_buildable[task] = 1
+        self.sched.newbuilable(task)
+
+    def task_completeoutright(self, task):
+        """
+        Mark a task as completed
+        Look at the reverse dependencies and mark any task with
+        completed dependencies as buildable
+        """
+        self.runq_complete[task] = 1
+        for revdep in self.rqdata.runq_revdeps[task]:
+            if self.runq_running[revdep] == 1:
+                continue
+            if self.runq_buildable[revdep] == 1:
+                continue
+            alldeps = 1
+            for dep in self.rqdata.runq_depends[revdep]:
+                if self.runq_complete[dep] != 1:
+                    alldeps = 0
+            if alldeps == 1:
+                self.setbuildable(revdep)
+                fn = self.rqdata.taskData.fn_index[self.rqdata.runq_fnid[revdep]]
+                taskname = self.rqdata.runq_task[revdep]
+                logger.debug(1, "Marking task %s (%s, %s) as buildable", revdep, fn, taskname)
+
+    def task_complete(self, task):
+        self.stats.taskCompleted()
+        bb.event.fire(runQueueTaskCompleted(task, self.stats, self.rq), self.cfgData)
+        self.task_completeoutright(task)
+
+    def task_fail(self, task, exitcode):
+        """
+        Called when a task has failed
+        Updates the state engine with the failure
+        """
+        self.stats.taskFailed()
+        fnid = self.rqdata.runq_fnid[task]
+        self.failed_fnids.append(fnid)
+        bb.event.fire(runQueueTaskFailed(task, self.stats, exitcode, self.rq), self.cfgData)
+        if self.rqdata.taskData.abort:
+            self.rq.state = runQueueCleanUp
+
+    def task_skip(self, task, reason):
+        self.runq_running[task] = 1
+        self.setbuildable(task)
+        bb.event.fire(runQueueTaskSkipped(task, self.stats, self.rq, reason), self.cfgData)
+        self.task_completeoutright(task)
+        self.stats.taskCompleted()
+        self.stats.taskSkipped()
+
+    def execute(self):
+        """
+        Run the tasks in a queue prepared by rqdata.prepare()
+        """
+
+        self.rq.read_workers()
+        
+
+        if self.stats.total == 0:
+            # nothing to do
+            self.rq.state = runQueueCleanUp
+
+        task = self.sched.next()
+        if task is not None:
+            fn = self.rqdata.taskData.fn_index[self.rqdata.runq_fnid[task]]
+            taskname = self.rqdata.runq_task[task]
+
+            if task in self.rq.scenequeue_covered:
+                logger.debug(2, "Setscene covered task %s (%s)", task,
+                                self.rqdata.get_user_idstring(task))
+                self.task_skip(task, "covered")
+                return True
+
+            if self.rq.check_stamp_task(task, taskname, cache=self.stampcache):
+                logger.debug(2, "Stamp current task %s (%s)", task,
+                                self.rqdata.get_user_idstring(task))
+                self.task_skip(task, "existing")
+                return True
+
+            taskdep = self.rqdata.dataCache.task_deps[fn]
+            if 'noexec' in taskdep and taskname in taskdep['noexec']:
+                startevent = runQueueTaskStarted(task, self.stats, self.rq,
+                                                 noexec=True)
+                bb.event.fire(startevent, self.cfgData)
+                self.runq_running[task] = 1
+                self.stats.taskActive()
+                if not self.cooker.configuration.dry_run:
+                    bb.build.make_stamp(taskname, self.rqdata.dataCache, fn)
+                self.task_complete(task)
+                return True
+            else:
+                startevent = runQueueTaskStarted(task, self.stats, self.rq)
+                bb.event.fire(startevent, self.cfgData)
+
+            taskdepdata = self.build_taskdepdata(task)
+
+            taskdep = self.rqdata.dataCache.task_deps[fn]
+            if 'fakeroot' in taskdep and taskname in taskdep['fakeroot'] and not self.cooker.configuration.dry_run:
+                if not self.rq.fakeworker:
+                    try:
+                        self.rq.start_fakeworker(self)
+                    except OSError as exc:
+                        logger.critical("Failed to spawn fakeroot worker to run %s:%s: %s" % (fn, taskname, str(exc)))
+                        self.rq.state = runQueueFailed
+                        return True
+                self.rq.fakeworker.stdin.write("<runtask>" + pickle.dumps((fn, task, taskname, False, self.cooker.collection.get_file_appends(fn), taskdepdata)) + "</runtask>")
+                self.rq.fakeworker.stdin.flush()
+            else:
+                self.rq.worker.stdin.write("<runtask>" + pickle.dumps((fn, task, taskname, False, self.cooker.collection.get_file_appends(fn), taskdepdata)) + "</runtask>")
+                self.rq.worker.stdin.flush()
+
+            self.build_stamps[task] = bb.build.stampfile(taskname, self.rqdata.dataCache, fn)
+            self.build_stamps2.append(self.build_stamps[task]) 
+            self.runq_running[task] = 1
+            self.stats.taskActive()
+            if self.stats.active < self.number_tasks:
+                return True
+
+        if self.stats.active > 0:
+            self.rq.read_workers()
+            return self.rq.active_fds()
+
+        if len(self.failed_fnids) != 0:
+            self.rq.state = runQueueFailed
+            return True
+
+        # Sanity Checks
+        for task in xrange(self.stats.total):
+            if self.runq_buildable[task] == 0:
+                logger.error("Task %s never buildable!", task)
+            if self.runq_running[task] == 0:
+                logger.error("Task %s never ran!", task)
+            if self.runq_complete[task] == 0:
+                logger.error("Task %s never completed!", task)
+        self.rq.state = runQueueComplete
+
+        return True
+
+    def build_taskdepdata(self, task):
+        taskdepdata = {}
+        next = self.rqdata.runq_depends[task]
+        next.add(task)
+        while next:
+            additional = []
+            for revdep in next:
+                fn = self.rqdata.taskData.fn_index[self.rqdata.runq_fnid[revdep]]
+                pn = self.rqdata.dataCache.pkg_fn[fn]
+                taskname = self.rqdata.runq_task[revdep]
+                deps = self.rqdata.runq_depends[revdep]
+                provides = self.rqdata.dataCache.fn_provides[fn]
+                taskdepdata[revdep] = [pn, taskname, fn, deps, provides]
+                for revdep2 in deps:
+                    if revdep2 not in taskdepdata:
+                        additional.append(revdep2)
+            next = additional
+
+        #bb.note("Task %s: " % task + str(taskdepdata).replace("], ", "],\n"))
+        return taskdepdata
+
+class RunQueueExecuteScenequeue(RunQueueExecute):
+    def __init__(self, rq):
+        RunQueueExecute.__init__(self, rq)
+
+        self.scenequeue_covered = set()
+        self.scenequeue_notcovered = set()
+        self.scenequeue_notneeded = set()
+
+        # If we don't have any setscene functions, skip this step
+        if len(self.rqdata.runq_setscene) == 0:
+            rq.scenequeue_covered = set()
+            rq.state = runQueueRunInit
+            return
+
+        self.stats = RunQueueStats(len(self.rqdata.runq_setscene))
+
+        sq_revdeps = []
+        sq_revdeps_new = []
+        sq_revdeps_squash = []
+        self.sq_harddeps = {}
+
+        # We need to construct a dependency graph for the setscene functions. Intermediate
+        # dependencies between the setscene tasks only complicate the code. This code
+        # therefore aims to collapse the huge runqueue dependency tree into a smaller one
+        # only containing the setscene functions.
+
+        for task in xrange(self.stats.total):
+            self.runq_running.append(0)
+            self.runq_complete.append(0)
+            self.runq_buildable.append(0)
+
+        # First process the chains up to the first setscene task.
+        endpoints = {}
+        for task in xrange(len(self.rqdata.runq_fnid)):
+            sq_revdeps.append(copy.copy(self.rqdata.runq_revdeps[task]))
+            sq_revdeps_new.append(set())
+            if (len(self.rqdata.runq_revdeps[task]) == 0) and task not in self.rqdata.runq_setscene:
+                endpoints[task] = set()
+
+        # Secondly process the chains between setscene tasks.
+        for task in self.rqdata.runq_setscene:
+            for dep in self.rqdata.runq_depends[task]:
+                    if dep not in endpoints:
+                        endpoints[dep] = set()
+                    endpoints[dep].add(task)
+
+        def process_endpoints(endpoints):
+            newendpoints = {}
+            for point, task in endpoints.items():
+                tasks = set()
+                if task:
+                    tasks |= task
+                if sq_revdeps_new[point]:
+                    tasks |= sq_revdeps_new[point]
+                sq_revdeps_new[point] = set()
+                if point in self.rqdata.runq_setscene:
+                    sq_revdeps_new[point] = tasks
+                for dep in self.rqdata.runq_depends[point]:
+                    if point in sq_revdeps[dep]:
+                        sq_revdeps[dep].remove(point)
+                    if tasks:
+                        sq_revdeps_new[dep] |= tasks
+                    if (len(sq_revdeps[dep]) == 0 or len(sq_revdeps_new[dep]) != 0) and dep not in self.rqdata.runq_setscene:
+                        newendpoints[dep] = task
+            if len(newendpoints) != 0:
+                process_endpoints(newendpoints)
+
+        process_endpoints(endpoints)
+
+        # Build a list of setscene tasks which are "unskippable"
+        # These are direct endpoints referenced by the build
+        endpoints2 = {}
+        sq_revdeps2 = []
+        sq_revdeps_new2 = []
+        def process_endpoints2(endpoints):
+            newendpoints = {}
+            for point, task in endpoints.items():
+                tasks = set([point])
+                if task:
+                    tasks |= task
+                if sq_revdeps_new2[point]:
+                    tasks |= sq_revdeps_new2[point]
+                sq_revdeps_new2[point] = set()
+                if point in self.rqdata.runq_setscene:
+                    sq_revdeps_new2[point] = tasks
+                for dep in self.rqdata.runq_depends[point]:
+                    if point in sq_revdeps2[dep]:
+                        sq_revdeps2[dep].remove(point)
+                    if tasks:
+                        sq_revdeps_new2[dep] |= tasks
+                    if (len(sq_revdeps2[dep]) == 0 or len(sq_revdeps_new2[dep]) != 0) and dep not in self.rqdata.runq_setscene:
+                        newendpoints[dep] = tasks
+            if len(newendpoints) != 0:
+                process_endpoints2(newendpoints)
+        for task in xrange(len(self.rqdata.runq_fnid)):
+            sq_revdeps2.append(copy.copy(self.rqdata.runq_revdeps[task]))
+            sq_revdeps_new2.append(set())
+            if (len(self.rqdata.runq_revdeps[task]) == 0) and task not in self.rqdata.runq_setscene:
+                endpoints2[task] = set()
+        process_endpoints2(endpoints2)
+        self.unskippable = []
+        for task in self.rqdata.runq_setscene:
+            if sq_revdeps_new2[task]:
+                self.unskippable.append(self.rqdata.runq_setscene.index(task))
+
+        for task in xrange(len(self.rqdata.runq_fnid)):
+            if task in self.rqdata.runq_setscene:
+                deps = set()
+                for dep in sq_revdeps_new[task]:
+                    deps.add(self.rqdata.runq_setscene.index(dep))
+                sq_revdeps_squash.append(deps)
+            elif len(sq_revdeps_new[task]) != 0:
+                bb.msg.fatal("RunQueue", "Something went badly wrong during scenequeue generation, aborting. Please report this problem.")
+
+        # Resolve setscene inter-task dependencies
+        # e.g. do_sometask_setscene[depends] = "targetname:do_someothertask_setscene"
+        # Note that anything explicitly depended upon will have its reverse dependencies removed to avoid circular dependencies
+        for task in self.rqdata.runq_setscene:
+                realid = self.rqdata.taskData.gettask_id(self.rqdata.taskData.fn_index[self.rqdata.runq_fnid[task]], self.rqdata.runq_task[task] + "_setscene", False)
+                idepends = self.rqdata.taskData.tasks_idepends[realid]
+                for (depid, idependtask) in idepends:
+                    if depid not in self.rqdata.taskData.build_targets:
+                        continue
+
+                    depdata = self.rqdata.taskData.build_targets[depid][0]
+                    if depdata is None:
+                         continue
+                    dep = self.rqdata.taskData.fn_index[depdata]
+                    taskid = self.rqdata.get_task_id(self.rqdata.taskData.getfn_id(dep), idependtask.replace("_setscene", ""))
+                    if taskid is None:
+                        bb.msg.fatal("RunQueue", "Task %s_setscene depends upon non-existent task %s:%s" % (self.rqdata.get_user_idstring(task), dep, idependtask))
+
+                    if not self.rqdata.runq_setscene.index(taskid) in self.sq_harddeps:
+                        self.sq_harddeps[self.rqdata.runq_setscene.index(taskid)] = set()
+                    self.sq_harddeps[self.rqdata.runq_setscene.index(taskid)].add(self.rqdata.runq_setscene.index(task))
+
+                    sq_revdeps_squash[self.rqdata.runq_setscene.index(task)].add(self.rqdata.runq_setscene.index(taskid))
+                    # Have to zero this to avoid circular dependencies
+                    sq_revdeps_squash[self.rqdata.runq_setscene.index(taskid)] = set()
+
+        for task in self.sq_harddeps:
+             for dep in self.sq_harddeps[task]:
+                 sq_revdeps_squash[dep].add(task)
+
+        #for task in xrange(len(sq_revdeps_squash)):
+        #    realtask = self.rqdata.runq_setscene[task]
+        #    bb.warn("Task %s: %s_setscene is %s " % (task, self.rqdata.get_user_idstring(realtask) , sq_revdeps_squash[task]))
+
+        self.sq_deps = []
+        self.sq_revdeps = sq_revdeps_squash
+        self.sq_revdeps2 = copy.deepcopy(self.sq_revdeps)
+
+        for task in xrange(len(self.sq_revdeps)):
+            self.sq_deps.append(set())
+        for task in xrange(len(self.sq_revdeps)):
+            for dep in self.sq_revdeps[task]:
+                self.sq_deps[dep].add(task)
+
+        for task in xrange(len(self.sq_revdeps)):
+            if len(self.sq_revdeps[task]) == 0:
+                self.runq_buildable[task] = 1
+
+        self.outrightfail = []
+        if self.rq.hashvalidate:
+            sq_hash = []
+            sq_hashfn = []
+            sq_fn = []
+            sq_taskname = []
+            sq_task = []
+            noexec = []
+            stamppresent = []
+            for task in xrange(len(self.sq_revdeps)):
+                realtask = self.rqdata.runq_setscene[task]
+                fn = self.rqdata.taskData.fn_index[self.rqdata.runq_fnid[realtask]]
+                taskname = self.rqdata.runq_task[realtask]
+                taskdep = self.rqdata.dataCache.task_deps[fn]
+
+                if 'noexec' in taskdep and taskname in taskdep['noexec']:
+                    noexec.append(task)
+                    self.task_skip(task)
+                    bb.build.make_stamp(taskname + "_setscene", self.rqdata.dataCache, fn)
+                    continue
+
+                if self.rq.check_stamp_task(realtask, taskname + "_setscene", cache=self.stampcache):
+                    logger.debug(2, 'Setscene stamp current for task %s(%s)', task, self.rqdata.get_user_idstring(realtask))
+                    stamppresent.append(task)
+                    self.task_skip(task)
+                    continue
+
+                if self.rq.check_stamp_task(realtask, taskname, recurse = True, cache=self.stampcache):
+                    logger.debug(2, 'Normal stamp current for task %s(%s)', task, self.rqdata.get_user_idstring(realtask))
+                    stamppresent.append(task)
+                    self.task_skip(task)
+                    continue
+
+                sq_fn.append(fn)
+                sq_hashfn.append(self.rqdata.dataCache.hashfn[fn])
+                sq_hash.append(self.rqdata.runq_hash[realtask])
+                sq_taskname.append(taskname)
+                sq_task.append(task)
+            call = self.rq.hashvalidate + "(sq_fn, sq_task, sq_hash, sq_hashfn, d)"
+            locs = { "sq_fn" : sq_fn, "sq_task" : sq_taskname, "sq_hash" : sq_hash, "sq_hashfn" : sq_hashfn, "d" : self.cooker.expanded_data }
+            valid = bb.utils.better_eval(call, locs)
+
+            valid_new = stamppresent
+            for v in valid:
+                valid_new.append(sq_task[v])
+
+            for task in xrange(len(self.sq_revdeps)):
+                if task not in valid_new and task not in noexec:
+                    realtask = self.rqdata.runq_setscene[task]
+                    logger.debug(2, 'No package found, so skipping setscene task %s',
+                                 self.rqdata.get_user_idstring(realtask))
+                    self.outrightfail.append(task)
+
+        logger.info('Executing SetScene Tasks')
+
+        self.rq.state = runQueueSceneRun
+
+    def scenequeue_updatecounters(self, task, fail = False):
+        for dep in self.sq_deps[task]:
+            if fail and task in self.sq_harddeps and dep in self.sq_harddeps[task]:
+                realtask = self.rqdata.runq_setscene[task]
+                realdep = self.rqdata.runq_setscene[dep]
+                logger.debug(2, "%s was unavailable and is a hard dependency of %s so skipping" % (self.rqdata.get_user_idstring(realtask), self.rqdata.get_user_idstring(realdep)))
+                self.scenequeue_updatecounters(dep, fail)
+                continue
+            if task not in self.sq_revdeps2[dep]:
+                # May already have been removed by the fail case above
+                continue
+            self.sq_revdeps2[dep].remove(task)
+            if len(self.sq_revdeps2[dep]) == 0:
+                self.runq_buildable[dep] = 1
+
+    def task_completeoutright(self, task):
+        """
+        Mark a task as completed
+        Look at the reverse dependencies and mark any task with
+        completed dependencies as buildable
+        """
+
+        index = self.rqdata.runq_setscene[task]
+        logger.debug(1, 'Found task %s which could be accelerated',
+                        self.rqdata.get_user_idstring(index))
+
+        self.scenequeue_covered.add(task)
+        self.scenequeue_updatecounters(task)
+
+    def task_complete(self, task):
+        self.stats.taskCompleted()
+        bb.event.fire(sceneQueueTaskCompleted(task, self.stats, self.rq), self.cfgData)
+        self.task_completeoutright(task)
+
+    def task_fail(self, task, result):
+        self.stats.taskFailed()
+        bb.event.fire(sceneQueueTaskFailed(task, self.stats, result, self), self.cfgData)
+        self.scenequeue_notcovered.add(task)
+        self.scenequeue_updatecounters(task, True)
+
+    def task_failoutright(self, task):
+        self.runq_running[task] = 1
+        self.runq_buildable[task] = 1
+        self.stats.taskCompleted()
+        self.stats.taskSkipped()
+        index = self.rqdata.runq_setscene[task]
+        self.scenequeue_notcovered.add(task)
+        self.scenequeue_updatecounters(task, True)
+
+    def task_skip(self, task):
+        self.runq_running[task] = 1
+        self.runq_buildable[task] = 1
+        self.task_completeoutright(task)
+        self.stats.taskCompleted()
+        self.stats.taskSkipped()
+
+    def execute(self):
+        """
+        Run the tasks in a queue prepared by prepare_runqueue
+        """
+
+        self.rq.read_workers()
+
+        task = None
+        if self.stats.active < self.number_tasks:
+            # Find the next setscene to run
+            for nexttask in xrange(self.stats.total):
+                if self.runq_buildable[nexttask] == 1 and self.runq_running[nexttask] != 1:
+                    if nexttask in self.unskippable:
+                        logger.debug(2, "Setscene task %s is unskippable" % self.rqdata.get_user_idstring(self.rqdata.runq_setscene[nexttask]))                      
+                    if nexttask not in self.unskippable and len(self.sq_revdeps[nexttask]) > 0 and self.sq_revdeps[nexttask].issubset(self.scenequeue_covered) and self.check_dependencies(nexttask, self.sq_revdeps[nexttask], True):
+                        realtask = self.rqdata.runq_setscene[nexttask]
+                        fn = self.rqdata.taskData.fn_index[self.rqdata.runq_fnid[realtask]]
+                        foundtarget = False
+                        for target in self.rqdata.target_pairs:
+                            if target[0] == fn and target[1] == self.rqdata.runq_task[realtask]:
+                                foundtarget = True
+                                break
+                        if not foundtarget:
+                            logger.debug(2, "Skipping setscene for task %s" % self.rqdata.get_user_idstring(self.rqdata.runq_setscene[nexttask]))
+                            self.task_skip(nexttask)
+                            self.scenequeue_notneeded.add(nexttask)
+                            return True
+                    if nexttask in self.outrightfail:
+                        self.task_failoutright(nexttask)
+                        return True
+                    task = nexttask
+                    break
+        if task is not None:
+            realtask = self.rqdata.runq_setscene[task]
+            fn = self.rqdata.taskData.fn_index[self.rqdata.runq_fnid[realtask]]
+
+            taskname = self.rqdata.runq_task[realtask] + "_setscene"
+            if self.rq.check_stamp_task(realtask, self.rqdata.runq_task[realtask], recurse = True, cache=self.stampcache):
+                logger.debug(2, 'Stamp for underlying task %s(%s) is current, so skipping setscene variant',
+                             task, self.rqdata.get_user_idstring(realtask))
+                self.task_failoutright(task)
+                return True
+
+            if self.cooker.configuration.force:
+                for target in self.rqdata.target_pairs:
+                    if target[0] == fn and target[1] == self.rqdata.runq_task[realtask]:
+                        self.task_failoutright(task)
+                        return True
+
+            if self.rq.check_stamp_task(realtask, taskname, cache=self.stampcache):
+                logger.debug(2, 'Setscene stamp current task %s(%s), so skip it and its dependencies',
+                             task, self.rqdata.get_user_idstring(realtask))
+                self.task_skip(task)
+                return True
+
+            startevent = sceneQueueTaskStarted(task, self.stats, self.rq)
+            bb.event.fire(startevent, self.cfgData)
+
+            taskdep = self.rqdata.dataCache.task_deps[fn]
+            if 'fakeroot' in taskdep and taskname in taskdep['fakeroot']:
+                if not self.rq.fakeworker:
+                    self.rq.start_fakeworker(self)
+                self.rq.fakeworker.stdin.write("<runtask>" + pickle.dumps((fn, realtask, taskname, True, self.cooker.collection.get_file_appends(fn), None)) + "</runtask>")
+                self.rq.fakeworker.stdin.flush()
+            else:
+                self.rq.worker.stdin.write("<runtask>" + pickle.dumps((fn, realtask, taskname, True, self.cooker.collection.get_file_appends(fn), None)) + "</runtask>")
+                self.rq.worker.stdin.flush()
+
+            self.runq_running[task] = 1
+            self.stats.taskActive()
+            if self.stats.active < self.number_tasks:
+                return True
+
+        if self.stats.active > 0:
+            self.rq.read_workers()
+            return self.rq.active_fds()
+
+        #for task in xrange(self.stats.total):
+        #    if self.runq_running[task] != 1:
+        #        buildable = self.runq_buildable[task]
+        #        revdeps = self.sq_revdeps[task]
+        #        bb.warn("Found we didn't run %s %s %s %s" % (task, buildable, str(revdeps), self.rqdata.get_user_idstring(self.rqdata.runq_setscene[task])))
+
+        # Convert scenequeue_covered task numbers into full taskgraph ids
+        oldcovered = self.scenequeue_covered
+        self.rq.scenequeue_covered = set()
+        for task in oldcovered:
+            self.rq.scenequeue_covered.add(self.rqdata.runq_setscene[task])
+        self.rq.scenequeue_notcovered = set()
+        for task in self.scenequeue_notcovered:
+            self.rq.scenequeue_notcovered.add(self.rqdata.runq_setscene[task])
+
+        logger.debug(1, 'We can skip tasks %s', sorted(self.rq.scenequeue_covered))
+
+        self.rq.state = runQueueRunInit
+
+        completeevent = sceneQueueComplete(self.stats, self.rq)
+        bb.event.fire(completeevent, self.cfgData)
+
+        return True
+
+    def runqueue_process_waitpid(self, task, status):
+        task = self.rq.rqdata.runq_setscene.index(task)
+
+        RunQueueExecute.runqueue_process_waitpid(self, task, status)
+
+class TaskFailure(Exception):
+    """
+    Exception raised when a task in a runqueue fails
+    """
+    def __init__(self, x):
+        self.args = x
+
+
+class runQueueExitWait(bb.event.Event):
+    """
+    Event when waiting for task processes to exit
+    """
+
+    def __init__(self, remain):
+        self.remain = remain
+        self.message = "Waiting for %s active tasks to finish" % remain
+        bb.event.Event.__init__(self)
+
+class runQueueEvent(bb.event.Event):
+    """
+    Base runQueue event class
+    """
+    def __init__(self, task, stats, rq):
+        self.taskid = task
+        self.taskstring = rq.rqdata.get_user_idstring(task)
+        self.taskname = rq.rqdata.get_task_name(task)
+        self.taskfile = rq.rqdata.get_task_file(task)
+        self.taskhash = rq.rqdata.get_task_hash(task)
+        self.stats = stats.copy()
+        bb.event.Event.__init__(self)
+
+class sceneQueueEvent(runQueueEvent):
+    """
+    Base sceneQueue event class
+    """
+    def __init__(self, task, stats, rq, noexec=False):
+        runQueueEvent.__init__(self, task, stats, rq)
+        realtask = rq.rqdata.runq_setscene[task]
+        self.taskstring = rq.rqdata.get_user_idstring(realtask, "_setscene")
+        self.taskname = rq.rqdata.get_task_name(realtask) + "_setscene"
+        self.taskfile = rq.rqdata.get_task_file(realtask)
+        self.taskhash = rq.rqdata.get_task_hash(realtask)
+
+class runQueueTaskStarted(runQueueEvent):
+    """
+    Event notifying a task was started
+    """
+    def __init__(self, task, stats, rq, noexec=False):
+        runQueueEvent.__init__(self, task, stats, rq)
+        self.noexec = noexec
+
+class sceneQueueTaskStarted(sceneQueueEvent):
+    """
+    Event notifying a setscene task was started
+    """
+    def __init__(self, task, stats, rq, noexec=False):
+        sceneQueueEvent.__init__(self, task, stats, rq)
+        self.noexec = noexec
+
+class runQueueTaskFailed(runQueueEvent):
+    """
+    Event notifying a task failed
+    """
+    def __init__(self, task, stats, exitcode, rq):
+        runQueueEvent.__init__(self, task, stats, rq)
+        self.exitcode = exitcode
+
+class sceneQueueTaskFailed(sceneQueueEvent):
+    """
+    Event notifying a setscene task failed
+    """
+    def __init__(self, task, stats, exitcode, rq):
+        sceneQueueEvent.__init__(self, task, stats, rq)
+        self.exitcode = exitcode
+
+class sceneQueueComplete(sceneQueueEvent):
+    """
+    Event when all the sceneQueue tasks are complete
+    """
+    def __init__(self, stats, rq):
+        self.stats = stats.copy()
+        bb.event.Event.__init__(self)
+
+class runQueueTaskCompleted(runQueueEvent):
+    """
+    Event notifying a task completed
+    """
+
+class sceneQueueTaskCompleted(sceneQueueEvent):
+    """
+    Event notifying a setscene task completed
+    """
+
+class runQueueTaskSkipped(runQueueEvent):
+    """
+    Event notifying a task was skipped
+    """
+    def __init__(self, task, stats, rq, reason):
+        runQueueEvent.__init__(self, task, stats, rq)
+        self.reason = reason
+
+class runQueuePipe():
+    """
+    Abstraction for a pipe between a worker thread and the server
+    """
+    def __init__(self, pipein, pipeout, d, rq, rqexec):
+        self.input = pipein
+        if pipeout:
+            pipeout.close()
+        bb.utils.nonblockingfd(self.input)
+        self.queue = ""
+        self.d = d
+        self.rq = rq
+        self.rqexec = rqexec
+
+    def setrunqueueexec(self, rqexec):
+        self.rqexec = rqexec
+
+    def read(self):
+        for w in [self.rq.worker, self.rq.fakeworker]:
+            if not w:
+                continue
+            w.poll()
+            if w.returncode is not None and not self.rq.teardown:
+                name = None
+                if self.rq.worker and w.pid == self.rq.worker.pid:
+                    name = "Worker"
+                elif self.rq.fakeworker and w.pid == self.rq.fakeworker.pid:
+                    name = "Fakeroot"
+                bb.error("%s process (%s) exited unexpectedly (%s), shutting down..." % (name, w.pid, str(w.returncode)))
+                self.rq.finish_runqueue(True)
+
+        start = len(self.queue)
+        try:
+            self.queue = self.queue + self.input.read(102400)
+        except (OSError, IOError) as e:
+            if e.errno != errno.EAGAIN:
+                raise
+        end = len(self.queue)
+        found = True
+        while found and len(self.queue):
+            found = False
+            index = self.queue.find("</event>")
+            while index != -1 and self.queue.startswith("<event>"):
+                try:
+                    event = pickle.loads(self.queue[7:index])
+                except ValueError as e:
+                    bb.msg.fatal("RunQueue", "failed load pickle '%s': '%s'" % (e, self.queue[7:index]))
+                bb.event.fire_from_worker(event, self.d)
+                found = True
+                self.queue = self.queue[index+8:]
+                index = self.queue.find("</event>")
+            index = self.queue.find("</exitcode>")
+            while index != -1 and self.queue.startswith("<exitcode>"):
+                try:
+                    task, status = pickle.loads(self.queue[10:index])
+                except ValueError as e:
+                    bb.msg.fatal("RunQueue", "failed load pickle '%s': '%s'" % (e, self.queue[10:index]))
+                self.rqexec.runqueue_process_waitpid(task, status)
+                found = True
+                self.queue = self.queue[index+11:]
+                index = self.queue.find("</exitcode>")
+        return (end > start)
+
+    def close(self):
+        while self.read():
+            continue
+        if len(self.queue) > 0:
+            print("Warning, worker left partial message: %s" % self.queue)
+        self.input.close()