scripts/lib/devtool/standard.py

# Development tool - standard commands plugin
#
# Copyright (C) 2014-2015 Intel Corporation
#
# 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.
"""Devtool standard plugins"""

import os
import sys
import re
import shutil
import tempfile
import logging
import argparse
import scriptutils
import errno
from collections import OrderedDict
from devtool import exec_build_env_command, setup_tinfoil, check_workspace_recipe, use_external_build, setup_git_repo, DevtoolError
from devtool import parse_recipe

logger = logging.getLogger('devtool')


def add(args, config, basepath, workspace):
    """Entry point for the devtool 'add' subcommand"""
    import bb
    import oe.recipeutils

    if args.recipename in workspace:
        raise DevtoolError("recipe %s is already in your workspace" %
                            args.recipename)

    reason = oe.recipeutils.validate_pn(args.recipename)
    if reason:
        raise DevtoolError(reason)

    # FIXME this ought to be in validate_pn but we're using that in other contexts
    if '/' in args.recipename:
        raise DevtoolError('"/" is not a valid character in recipe names')

    srctree = os.path.abspath(args.srctree)
    if os.path.exists(srctree):
        if args.fetch:
            if not os.path.isdir(srctree):
                raise DevtoolError("Cannot fetch into source tree path %s as "
                                   "it exists and is not a directory" %
                                   srctree)
            elif os.listdir(srctree):
                raise DevtoolError("Cannot fetch into source tree path %s as "
                                   "it already exists and is non-empty" %
                                   srctree)
    elif not args.fetch:
        raise DevtoolError("Specified source tree %s could not be found" %
                           srctree)

    appendpath = os.path.join(config.workspace_path, 'appends')
    if not os.path.exists(appendpath):
        os.makedirs(appendpath)

    recipedir = os.path.join(config.workspace_path, 'recipes', args.recipename)
    bb.utils.mkdirhier(recipedir)
    rfv = None
    if args.version:
        if '_' in args.version or ' ' in args.version:
            raise DevtoolError('Invalid version string "%s"' % args.version)
        rfv = args.version
    if args.fetch:
        if args.fetch.startswith('git://'):
            rfv = 'git'
        elif args.fetch.startswith('svn://'):
            rfv = 'svn'
        elif args.fetch.startswith('hg://'):
            rfv = 'hg'
    if rfv:
        bp = "%s_%s" % (args.recipename, rfv)
    else:
        bp = args.recipename
    recipefile = os.path.join(recipedir, "%s.bb" % bp)
    if args.color == 'auto' and sys.stdout.isatty():
        color = 'always'
    else:
        color = args.color
    extracmdopts = ''
    if args.fetch:
        source = args.fetch
        extracmdopts = '-x %s' % srctree
    else:
        source = srctree
    if args.version:
        extracmdopts += ' -V %s' % args.version
    if args.binary:
        extracmdopts += ' -b'
    try:
        stdout, _ = exec_build_env_command(config.init_path, basepath, 'recipetool --color=%s create -o %s "%s" %s' % (color, recipefile, source, extracmdopts))
    except bb.process.ExecutionError as e:
        raise DevtoolError('Command \'%s\' failed:\n%s' % (e.command, e.stdout))

    _add_md5(config, args.recipename, recipefile)

    if args.fetch and not args.no_git:
        setup_git_repo(srctree, args.version, 'devtool')

    initial_rev = None
    if os.path.exists(os.path.join(srctree, '.git')):
        (stdout, _) = bb.process.run('git rev-parse HEAD', cwd=srctree)
        initial_rev = stdout.rstrip()

    tinfoil = setup_tinfoil(config_only=True, basepath=basepath)
    rd = oe.recipeutils.parse_recipe(recipefile, None, tinfoil.config_data)
    if not rd:
        return 1

    appendfile = os.path.join(appendpath, '%s.bbappend' % bp)
    with open(appendfile, 'w') as f:
        f.write('inherit externalsrc\n')
        f.write('EXTERNALSRC = "%s"\n' % srctree)

        b_is_s = use_external_build(args.same_dir, args.no_same_dir, rd)
        if b_is_s:
            f.write('EXTERNALSRC_BUILD = "%s"\n' % srctree)
        if initial_rev:
            f.write('\n# initial_rev: %s\n' % initial_rev)

        if args.binary:
            f.write('do_install_append() {\n')
            f.write('    rm -rf ${D}/.git\n')
            f.write('    rm -f ${D}/singletask.lock\n')
            f.write('}\n')

    _add_md5(config, args.recipename, appendfile)

    logger.info('Recipe %s has been automatically created; further editing may be required to make it fully functional' % recipefile)

    tinfoil.shutdown()

    return 0


def _check_compatible_recipe(pn, d):
    """Check if the recipe is supported by devtool"""
    if pn == 'perf':
        raise DevtoolError("The perf recipe does not actually check out "
                           "source and thus cannot be supported by this tool")

    if pn in ['kernel-devsrc', 'package-index'] or pn.startswith('gcc-source'):
        raise DevtoolError("The %s recipe is not supported by this tool" % pn)

    if bb.data.inherits_class('image', d):
        raise DevtoolError("The %s recipe is an image, and therefore is not "
                           "supported by this tool" % pn)

    if bb.data.inherits_class('populate_sdk', d):
        raise DevtoolError("The %s recipe is an SDK, and therefore is not "
                           "supported by this tool" % pn)

    if bb.data.inherits_class('packagegroup', d):
        raise DevtoolError("The %s recipe is a packagegroup, and therefore is "
                           "not supported by this tool" % pn)

    if bb.data.inherits_class('meta', d):
        raise DevtoolError("The %s recipe is a meta-recipe, and therefore is "
                           "not supported by this tool" % pn)

    if bb.data.inherits_class('externalsrc', d) and d.getVar('EXTERNALSRC', True):
        raise DevtoolError("externalsrc is currently enabled for the %s "
                           "recipe. This prevents the normal do_patch task "
                           "from working. You will need to disable this "
                           "first." % pn)

def _move_file(src, dst):
    """Move a file. Creates all the directory components of destination path."""
    dst_d = os.path.dirname(dst)
    if dst_d:
        bb.utils.mkdirhier(dst_d)
    shutil.move(src, dst)

def _git_ls_tree(repodir, treeish='HEAD', recursive=False):
    """List contents of a git treeish"""
    import bb
    cmd = ['git', 'ls-tree', '-z', treeish]
    if recursive:
        cmd.append('-r')
    out, _ = bb.process.run(cmd, cwd=repodir)
    ret = {}
    for line in out.split('\0'):
        if line:
            split = line.split(None, 4)
            ret[split[3]] = split[0:3]
    return ret

def _git_exclude_path(srctree, path):
    """Return pathspec (list of paths) that excludes certain path"""
    # NOTE: "Filtering out" files/paths in this way is not entirely reliable -
    # we don't catch files that are deleted, for example. A more reliable way
    # to implement this would be to use "negative pathspecs" which were
    # introduced in Git v1.9.0. Revisit this when/if the required Git version
    # becomes greater than that.
    path = os.path.normpath(path)
    recurse = True if len(path.split(os.path.sep)) > 1 else False
    git_files = _git_ls_tree(srctree, 'HEAD', recurse).keys()
    if path in git_files:
        git_files.remove(path)
        return git_files
    else:
        return ['.']

def _ls_tree(directory):
    """Recursive listing of files in a directory"""
    ret = []
    for root, dirs, files in os.walk(directory):
        ret.extend([os.path.relpath(os.path.join(root, fname), directory) for
                    fname in files])
    return ret


def extract(args, config, basepath, workspace):
    """Entry point for the devtool 'extract' subcommand"""
    import bb

    tinfoil = _prep_extract_operation(config, basepath, args.recipename)
    if not tinfoil:
        # Error already shown
        return 1

    rd = parse_recipe(config, tinfoil, args.recipename, True)
    if not rd:
        return 1

    srctree = os.path.abspath(args.srctree)
    initial_rev = _extract_source(srctree, args.keep_temp, args.branch, rd)
    logger.info('Source tree extracted to %s' % srctree)

    if initial_rev:
        return 0
    else:
        return 1

class BbTaskExecutor(object):
    """Class for executing bitbake tasks for a recipe

    FIXME: This is very awkward. Unfortunately it's not currently easy to
    properly execute tasks outside of bitbake itself, until then this has to
    suffice if we are to handle e.g. linux-yocto's extra tasks
    """

    def __init__(self, rdata):
        self.rdata = rdata
        self.executed = []

    def exec_func(self, func, report):
        """Run bitbake task function"""
        if not func in self.executed:
            deps = self.rdata.getVarFlag(func, 'deps')
            if deps:
                for taskdepfunc in deps:
                    self.exec_func(taskdepfunc, True)
            if report:
                logger.info('Executing %s...' % func)
            fn = self.rdata.getVar('FILE', True)
            localdata = bb.build._task_data(fn, func, self.rdata)
            bb.build.exec_func(func, localdata)
            self.executed.append(func)


def _prep_extract_operation(config, basepath, recipename):
    """HACK: Ugly workaround for making sure that requirements are met when
       trying to extract a package. Returns the tinfoil instance to be used."""
    tinfoil = setup_tinfoil(basepath=basepath)
    rd = parse_recipe(config, tinfoil, recipename, True)
    if not rd:
        return None

    if bb.data.inherits_class('kernel-yocto', rd):
        tinfoil.shutdown()
        try:
            stdout, _ = exec_build_env_command(config.init_path, basepath,
                                               'bitbake kern-tools-native')
            tinfoil = setup_tinfoil(basepath=basepath)
        except bb.process.ExecutionError as err:
            raise DevtoolError("Failed to build kern-tools-native:\n%s" %
                               err.stdout)
    return tinfoil


def _extract_source(srctree, keep_temp, devbranch, d):
    """Extract sources of a recipe"""
    import bb.event
    import oe.recipeutils

    def eventfilter(name, handler, event, d):
        """Bitbake event filter for devtool extract operation"""
        if name == 'base_eventhandler':
            return True
        else:
            return False

    if hasattr(bb.event, 'set_eventfilter'):
        bb.event.set_eventfilter(eventfilter)

    pn = d.getVar('PN', True)

    _check_compatible_recipe(pn, d)

    if os.path.exists(srctree):
        if not os.path.isdir(srctree):
            raise DevtoolError("output path %s exists and is not a directory" %
                               srctree)
        elif os.listdir(srctree):
            raise DevtoolError("output path %s already exists and is "
                               "non-empty" % srctree)

    if 'noexec' in (d.getVarFlags('do_unpack', False) or []):
        raise DevtoolError("The %s recipe has do_unpack disabled, unable to "
                           "extract source" % pn)

    # Prepare for shutil.move later on
    bb.utils.mkdirhier(srctree)
    os.rmdir(srctree)

    # We don't want notes to be printed, they are too verbose
    origlevel = bb.logger.getEffectiveLevel()
    if logger.getEffectiveLevel() > logging.DEBUG:
        bb.logger.setLevel(logging.WARNING)

    initial_rev = None
    tempdir = tempfile.mkdtemp(prefix='devtool')
    try:
        crd = d.createCopy()
        # Make a subdir so we guard against WORKDIR==S
        workdir = os.path.join(tempdir, 'workdir')
        crd.setVar('WORKDIR', workdir)
        crd.setVar('T', os.path.join(tempdir, 'temp'))
        if not crd.getVar('S', True).startswith(workdir):
            # Usually a shared workdir recipe (kernel, gcc)
            # Try to set a reasonable default
            if bb.data.inherits_class('kernel', d):
                crd.setVar('S', '${WORKDIR}/source')
            else:
                crd.setVar('S', '${WORKDIR}/%s' % os.path.basename(d.getVar('S', True)))
        if bb.data.inherits_class('kernel', d):
            # We don't want to move the source to STAGING_KERNEL_DIR here
            crd.setVar('STAGING_KERNEL_DIR', '${S}')

        task_executor = BbTaskExecutor(crd)

        crd.setVar('EXTERNALSRC_forcevariable', '')

        logger.info('Fetching %s...' % pn)
        task_executor.exec_func('do_fetch', False)
        logger.info('Unpacking...')
        task_executor.exec_func('do_unpack', False)
        if bb.data.inherits_class('kernel-yocto', d):
            # Extra step for kernel to populate the source directory
            logger.info('Doing kernel checkout...')
            task_executor.exec_func('do_kernel_checkout', False)
        srcsubdir = crd.getVar('S', True)

        # Move local source files into separate subdir
        recipe_patches = [os.path.basename(patch) for patch in
                          oe.recipeutils.get_recipe_patches(crd)]
        local_files = oe.recipeutils.get_recipe_local_files(crd)
        local_files = [fname for fname in local_files if
                       os.path.exists(os.path.join(workdir, fname))]
        if local_files:
            for fname in local_files:
                _move_file(os.path.join(workdir, fname),
                           os.path.join(tempdir, 'oe-local-files', fname))
            with open(os.path.join(tempdir, 'oe-local-files', '.gitignore'),
                      'w') as f:
                f.write('# Ignore local files, by default. Remove this file '
                        'if you want to commit the directory to Git\n*\n')

        if srcsubdir == workdir:
            # Find non-patch non-local sources that were "unpacked" to srctree
            # directory
            src_files = [fname for fname in _ls_tree(workdir) if
                         os.path.basename(fname) not in recipe_patches]
            # Force separate S so that patch files can be left out from srctree
            srcsubdir = tempfile.mkdtemp(dir=workdir)
            crd.setVar('S', srcsubdir)
            # Move source files to S
            for path in src_files:
                _move_file(os.path.join(workdir, path),
                           os.path.join(srcsubdir, path))
        elif os.path.dirname(srcsubdir) != workdir:
            # Handle if S is set to a subdirectory of the source
            srcsubdir = os.path.join(workdir, os.path.relpath(srcsubdir, workdir).split(os.sep)[0])

        scriptutils.git_convert_standalone_clone(srcsubdir)

        patchdir = os.path.join(srcsubdir, 'patches')
        haspatches = False
        if os.path.exists(patchdir):
            if os.listdir(patchdir):
                haspatches = True
            else:
                os.rmdir(patchdir)
        # Make sure that srcsubdir exists
        bb.utils.mkdirhier(srcsubdir)
        if not os.path.exists(srcsubdir) or not os.listdir(srcsubdir):
            logger.warning("no source unpacked to S, either the %s recipe "
                           "doesn't use any source or the correct source "
                           "directory could not be determined" % pn)

        setup_git_repo(srcsubdir, crd.getVar('PV', True), devbranch)

        (stdout, _) = bb.process.run('git rev-parse HEAD', cwd=srcsubdir)
        initial_rev = stdout.rstrip()

        crd.setVar('PATCHTOOL', 'git')

        logger.info('Patching...')
        task_executor.exec_func('do_patch', False)

        bb.process.run('git tag -f devtool-patched', cwd=srcsubdir)

        if os.path.exists(patchdir):
            shutil.rmtree(patchdir)
            if haspatches:
                bb.process.run('git checkout patches', cwd=srcsubdir)

        # Move oe-local-files directory to srctree
        if os.path.exists(os.path.join(tempdir, 'oe-local-files')):
            logger.info('Adding local source files to srctree...')
            shutil.move(os.path.join(tempdir, 'oe-local-files'), srcsubdir)


        shutil.move(srcsubdir, srctree)
    finally:
        bb.logger.setLevel(origlevel)

        if keep_temp:
            logger.info('Preserving temporary directory %s' % tempdir)
        else:
            shutil.rmtree(tempdir)
    return initial_rev

def _add_md5(config, recipename, filename):
    """Record checksum of a file (or recursively for a directory) to the md5-file of the workspace"""
    import bb.utils

    def addfile(fn):
        md5 = bb.utils.md5_file(fn)
        with open(os.path.join(config.workspace_path, '.devtool_md5'), 'a') as f:
            f.write('%s|%s|%s\n' % (recipename, os.path.relpath(fn, config.workspace_path), md5))

    if os.path.isdir(filename):
        for root, _, files in os.walk(filename):
            for f in files:
                addfile(os.path.join(root, f))
    else:
        addfile(filename)

def _check_preserve(config, recipename):
    """Check if a file was manually changed and needs to be saved in 'attic'
       directory"""
    import bb.utils
    origfile = os.path.join(config.workspace_path, '.devtool_md5')
    newfile = os.path.join(config.workspace_path, '.devtool_md5_new')
    preservepath = os.path.join(config.workspace_path, 'attic')
    with open(origfile, 'r') as f:
        with open(newfile, 'w') as tf:
            for line in f.readlines():
                splitline = line.rstrip().split('|')
                if splitline[0] == recipename:
                    removefile = os.path.join(config.workspace_path, splitline[1])
                    try:
                        md5 = bb.utils.md5_file(removefile)
                    except IOError as err:
                        if err.errno == 2:
                            # File no longer exists, skip it
                            continue
                        else:
                            raise
                    if splitline[2] != md5:
                        bb.utils.mkdirhier(preservepath)
                        preservefile = os.path.basename(removefile)
                        logger.warn('File %s modified since it was written, preserving in %s' % (preservefile, preservepath))
                        shutil.move(removefile, os.path.join(preservepath, preservefile))
                    else:
                        os.remove(removefile)
                else:
                    tf.write(line)
    os.rename(newfile, origfile)

def modify(args, config, basepath, workspace):
    """Entry point for the devtool 'modify' subcommand"""
    import bb
    import oe.recipeutils

    if args.recipename in workspace:
        raise DevtoolError("recipe %s is already in your workspace" %
                           args.recipename)

    if not args.extract and not os.path.isdir(args.srctree):
        raise DevtoolError("directory %s does not exist or not a directory "
                           "(specify -x to extract source from recipe)" %
                           args.srctree)
    if args.extract:
        tinfoil = _prep_extract_operation(config, basepath, args.recipename)
        if not tinfoil:
            # Error already shown
            return 1
    else:
        tinfoil = setup_tinfoil(basepath=basepath)

    rd = parse_recipe(config, tinfoil, args.recipename, True)
    if not rd:
        return 1

    pn = rd.getVar('PN', True)
    if pn != args.recipename:
        logger.info('Mapping %s to %s' % (args.recipename, pn))
    if pn in workspace:
        raise DevtoolError("recipe %s is already in your workspace" %
                           pn)

    recipefile = rd.getVar('FILE', True)
    appendname = os.path.splitext(os.path.basename(recipefile))[0]
    if args.wildcard:
        appendname = re.sub(r'_.*', '_%', appendname)
    appendpath = os.path.join(config.workspace_path, 'appends')
    appendfile = os.path.join(appendpath, appendname + '.bbappend')
    if os.path.exists(appendfile):
        raise DevtoolError("Another variant of recipe %s is already in your "
                           "workspace (only one variant of a recipe can "
                           "currently be worked on at once)"
                           % pn)

    _check_compatible_recipe(pn, rd)

    initial_rev = None
    commits = []
    srctree = os.path.abspath(args.srctree)
    if args.extract:
        initial_rev = _extract_source(args.srctree, False, args.branch, rd)
        if not initial_rev:
            return 1
        logger.info('Source tree extracted to %s' % srctree)
        # Get list of commits since this revision
        (stdout, _) = bb.process.run('git rev-list --reverse %s..HEAD' % initial_rev, cwd=args.srctree)
        commits = stdout.split()
    else:
        if os.path.exists(os.path.join(args.srctree, '.git')):
            # Check if it's a tree previously extracted by us
            try:
                (stdout, _) = bb.process.run('git branch --contains devtool-base', cwd=args.srctree)
            except bb.process.ExecutionError:
                stdout = ''
            for line in stdout.splitlines():
                if line.startswith('*'):
                    (stdout, _) = bb.process.run('git rev-parse devtool-base', cwd=args.srctree)
                    initial_rev = stdout.rstrip()
            if not initial_rev:
                # Otherwise, just grab the head revision
                (stdout, _) = bb.process.run('git rev-parse HEAD', cwd=args.srctree)
                initial_rev = stdout.rstrip()

    # Check that recipe isn't using a shared workdir
    s = os.path.abspath(rd.getVar('S', True))
    workdir = os.path.abspath(rd.getVar('WORKDIR', True))
    if s.startswith(workdir) and s != workdir and os.path.dirname(s) != workdir:
        # Handle if S is set to a subdirectory of the source
        srcsubdir = os.path.relpath(s, workdir).split(os.sep, 1)[1]
        srctree = os.path.join(srctree, srcsubdir)

    if not os.path.exists(appendpath):
        os.makedirs(appendpath)
    with open(appendfile, 'w') as f:
        f.write('FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"\n')
        # Local files can be modified/tracked in separate subdir under srctree
        # Mostly useful for packages with S != WORKDIR
        f.write('FILESPATH_prepend := "%s:"\n' %
                os.path.join(srctree, 'oe-local-files'))

        f.write('\ninherit externalsrc\n')
        f.write('# NOTE: We use pn- overrides here to avoid affecting multiple variants in the case where the recipe uses BBCLASSEXTEND\n')
        f.write('EXTERNALSRC_pn-%s = "%s"\n' % (pn, srctree))

        b_is_s = use_external_build(args.same_dir, args.no_same_dir, rd)
        if b_is_s:
            f.write('EXTERNALSRC_BUILD_pn-%s = "%s"\n' % (pn, srctree))

        if bb.data.inherits_class('kernel', rd):
            f.write('SRCTREECOVEREDTASKS = "do_validate_branches do_kernel_checkout do_fetch do_unpack do_patch"\n')
        if initial_rev:
            f.write('\n# initial_rev: %s\n' % initial_rev)
            for commit in commits:
                f.write('# commit: %s\n' % commit)

    _add_md5(config, pn, appendfile)

    logger.info('Recipe %s now set up to build from %s' % (pn, srctree))

    return 0

def _get_patchset_revs(args, srctree, recipe_path):
    """Get initial and update rev of a recipe. These are the start point of the
    whole patchset and start point for the patches to be re-generated/updated.
    """
    import bb

    if args.initial_rev:
        return args.initial_rev, args.initial_rev

    # Parse initial rev from recipe
    commits = []
    initial_rev = None
    with open(recipe_path, 'r') as f:
        for line in f:
            if line.startswith('# initial_rev:'):
                initial_rev = line.split(':')[-1].strip()
            elif line.startswith('# commit:'):
                commits.append(line.split(':')[-1].strip())

    update_rev = initial_rev
    changed_revs = None
    if initial_rev:
        # Find first actually changed revision
        stdout, _ = bb.process.run('git rev-list --reverse %s..HEAD' %
                                   initial_rev, cwd=srctree)
        newcommits = stdout.split()
        for i in xrange(min(len(commits), len(newcommits))):
            if newcommits[i] == commits[i]:
                update_rev = commits[i]

        try:
            stdout, _ = bb.process.run('git cherry devtool-patched',
                                        cwd=srctree)
        except bb.process.ExecutionError as err:
            stdout = None

        if stdout is not None:
            changed_revs = []
            for line in stdout.splitlines():
                if line.startswith('+ '):
                    rev = line.split()[1]
                    if rev in newcommits:
                        changed_revs.append(rev)

    return initial_rev, update_rev, changed_revs

def _remove_file_entries(srcuri, filelist):
    """Remove file:// entries from SRC_URI"""
    remaining = filelist[:]
    entries = []
    for fname in filelist:
        basename = os.path.basename(fname)
        for i in xrange(len(srcuri)):
            if (srcuri[i].startswith('file://') and
                    os.path.basename(srcuri[i].split(';')[0]) == basename):
                entries.append(srcuri[i])
                remaining.remove(fname)
                srcuri.pop(i)
                break
    return entries, remaining

def _remove_source_files(args, files, destpath):
    """Unlink existing patch files"""
    for path in files:
        if args.append:
            if not destpath:
                raise Exception('destpath should be set here')
            path = os.path.join(destpath, os.path.basename(path))

        if os.path.exists(path):
            logger.info('Removing file %s' % path)
            # FIXME "git rm" here would be nice if the file in question is
            #       tracked
            # FIXME there's a chance that this file is referred to by
            #       another recipe, in which case deleting wouldn't be the
            #       right thing to do
            os.remove(path)
            # Remove directory if empty
            try:
                os.rmdir(os.path.dirname(path))
            except OSError as ose:
                if ose.errno != errno.ENOTEMPTY:
                    raise


def _export_patches(srctree, rd, start_rev, destdir):
    """Export patches from srctree to given location.
       Returns three-tuple of dicts:
         1. updated - patches that already exist in SRCURI
         2. added - new patches that don't exist in SRCURI
         3  removed - patches that exist in SRCURI but not in exported patches
      In each dict the key is the 'basepath' of the URI and value is the
      absolute path to the existing file in recipe space (if any).
    """
    import oe.recipeutils
    from oe.patch import GitApplyTree
    updated = OrderedDict()
    added = OrderedDict()
    seqpatch_re = re.compile('^([0-9]{4}-)?(.+)')

    existing_patches = dict((os.path.basename(path), path) for path in
                            oe.recipeutils.get_recipe_patches(rd))

    # Generate patches from Git, exclude local files directory
    patch_pathspec = _git_exclude_path(srctree, 'oe-local-files')
    GitApplyTree.extractPatches(srctree, start_rev, destdir, patch_pathspec)

    new_patches = sorted(os.listdir(destdir))
    for new_patch in new_patches:
        # Strip numbering from patch names. If it's a git sequence named patch,
        # the numbers might not match up since we are starting from a different
        # revision This does assume that people are using unique shortlog
        # values, but they ought to be anyway...
        new_basename = seqpatch_re.match(new_patch).group(2)
        found = False
        for old_patch in existing_patches:
            old_basename = seqpatch_re.match(old_patch).group(2)
            if new_basename == old_basename:
                updated[new_patch] = existing_patches.pop(old_patch)
                found = True
                # Rename patch files
                if new_patch != old_patch:
                    os.rename(os.path.join(destdir, new_patch),
                              os.path.join(destdir, old_patch))
                break
        if not found:
            added[new_patch] = None
    return (updated, added, existing_patches)


def _export_local_files(srctree, rd, destdir):
    """Copy local files from srctree to given location.
       Returns three-tuple of dicts:
         1. updated - files that already exist in SRCURI
         2. added - new files files that don't exist in SRCURI
         3  removed - files that exist in SRCURI but not in exported files
      In each dict the key is the 'basepath' of the URI and value is the
      absolute path to the existing file in recipe space (if any).
    """
    import oe.recipeutils

    # Find out local files (SRC_URI files that exist in the "recipe space").
    # Local files that reside in srctree are not included in patch generation.
    # Instead they are directly copied over the original source files (in
    # recipe space).
    existing_files = oe.recipeutils.get_recipe_local_files(rd)
    new_set = None
    updated = OrderedDict()
    added = OrderedDict()
    removed = OrderedDict()
    git_files = _git_ls_tree(srctree)
    if 'oe-local-files' in git_files:
        # If tracked by Git, take the files from srctree HEAD. First get
        # the tree object of the directory
        tmp_index = os.path.join(srctree, '.git', 'index.tmp.devtool')
        tree = git_files['oe-local-files'][2]
        bb.process.run(['git', 'checkout', tree, '--', '.'], cwd=srctree,
                        env=dict(os.environ, GIT_WORK_TREE=destdir,
                                 GIT_INDEX_FILE=tmp_index))
        new_set = _git_ls_tree(srctree, tree, True).keys()
    elif os.path.isdir(os.path.join(srctree, 'oe-local-files')):
        # If not tracked by Git, just copy from working copy
        new_set = _ls_tree(os.path.join(srctree, 'oe-local-files'))
        bb.process.run(['cp', '-ax',
                        os.path.join(srctree, 'oe-local-files', '.'), destdir])
    if new_set is not None:
        for fname in new_set:
            if fname in existing_files:
                updated[fname] = existing_files.pop(fname)
            elif fname != '.gitignore':
                added[fname] = None

        removed = existing_files
    return (updated, added, removed)


def _update_recipe_srcrev(args, srctree, rd, config_data):
    """Implement the 'srcrev' mode of update-recipe"""
    import bb
    import oe.recipeutils

    recipefile = rd.getVar('FILE', True)
    logger.info('Updating SRCREV in recipe %s' % os.path.basename(recipefile))

    # Get HEAD revision
    try:
        stdout, _ = bb.process.run('git rev-parse HEAD', cwd=srctree)
    except bb.process.ExecutionError as err:
        raise DevtoolError('Failed to get HEAD revision in %s: %s' %
                           (srctree, err))
    srcrev = stdout.strip()
    if len(srcrev) != 40:
        raise DevtoolError('Invalid hash returned by git: %s' % stdout)

    destpath = None
    remove_files = []
    patchfields = {}
    patchfields['SRCREV'] = srcrev
    orig_src_uri = rd.getVar('SRC_URI', False) or ''
    srcuri = orig_src_uri.split()
    tempdir = tempfile.mkdtemp(prefix='devtool')
    update_srcuri = False
    try:
        local_files_dir = tempfile.mkdtemp(dir=tempdir)
        upd_f, new_f, del_f = _export_local_files(srctree, rd, local_files_dir)
        if not args.no_remove:
            # Find list of existing patches in recipe file
            patches_dir = tempfile.mkdtemp(dir=tempdir)
            old_srcrev = (rd.getVar('SRCREV', False) or '')
            upd_p, new_p, del_p = _export_patches(srctree, rd, old_srcrev,
                                                  patches_dir)

            # Remove deleted local files and "overlapping" patches
            remove_files = del_f.values() + upd_p.values()
            if remove_files:
                removedentries = _remove_file_entries(srcuri, remove_files)[0]
                update_srcuri = True

        if args.append:
            files = dict((os.path.join(local_files_dir, key), val) for
                          key, val in upd_f.items() + new_f.items())
            removevalues = {}
            if update_srcuri:
                removevalues  = {'SRC_URI': removedentries}
                patchfields['SRC_URI'] = '\\\n    '.join(srcuri)
            _, destpath = oe.recipeutils.bbappend_recipe(
                    rd, args.append, files, wildcardver=args.wildcard_version,
                    extralines=patchfields, removevalues=removevalues)
        else:
            files_dir = os.path.join(os.path.dirname(recipefile),
                                     rd.getVar('BPN', True))
            for basepath, path in upd_f.iteritems():
                logger.info('Updating file %s' % basepath)
                _move_file(os.path.join(local_files_dir, basepath), path)
                update_srcuri= True
            for basepath, path in new_f.iteritems():
                logger.info('Adding new file %s' % basepath)
                _move_file(os.path.join(local_files_dir, basepath),
                           os.path.join(files_dir, basepath))
                srcuri.append('file://%s' % basepath)
                update_srcuri = True
            if update_srcuri:
                patchfields['SRC_URI'] = ' '.join(srcuri)
            oe.recipeutils.patch_recipe(rd, recipefile, patchfields)
    finally:
        shutil.rmtree(tempdir)
    if not 'git://' in orig_src_uri:
        logger.info('You will need to update SRC_URI within the recipe to '
                    'point to a git repository where you have pushed your '
                    'changes')

    _remove_source_files(args, remove_files, destpath)

def _update_recipe_patch(args, config, srctree, rd, config_data):
    """Implement the 'patch' mode of update-recipe"""
    import bb
    import oe.recipeutils

    recipefile = rd.getVar('FILE', True)
    append = os.path.join(config.workspace_path, 'appends', '%s.bbappend' %
                          os.path.splitext(os.path.basename(recipefile))[0])
    if not os.path.exists(append):
        raise DevtoolError('unable to find workspace bbappend for recipe %s' %
                           args.recipename)

    initial_rev, update_rev, changed_revs = _get_patchset_revs(args, srctree, append)
    if not initial_rev:
        raise DevtoolError('Unable to find initial revision - please specify '
                           'it with --initial-rev')

    tempdir = tempfile.mkdtemp(prefix='devtool')
    try:
        local_files_dir = tempfile.mkdtemp(dir=tempdir)
        upd_f, new_f, del_f = _export_local_files(srctree, rd, local_files_dir)

        remove_files = []
        if not args.no_remove:
            # Get all patches from source tree and check if any should be removed
            all_patches_dir = tempfile.mkdtemp(dir=tempdir)
            upd_p, new_p, del_p = _export_patches(srctree, rd, initial_rev,
                                                  all_patches_dir)
            # Remove deleted local files and  patches
            remove_files = del_f.values() + del_p.values()

        # Get updated patches from source tree
        patches_dir = tempfile.mkdtemp(dir=tempdir)
        upd_p, new_p, del_p = _export_patches(srctree, rd, update_rev,
                                              patches_dir)
        updatefiles = False
        updaterecipe = False
        destpath = None
        srcuri = (rd.getVar('SRC_URI', False) or '').split()
        if args.append:
            files = dict((os.path.join(local_files_dir, key), val) for
                         key, val in upd_f.items() + new_f.items())
            files.update(dict((os.path.join(patches_dir, key), val) for
                              key, val in upd_p.items() + new_p.items()))
            if files or remove_files:
                removevalues = None
                if remove_files:
                    removedentries, remaining = _remove_file_entries(
                                                    srcuri, remove_files)
                    if removedentries or remaining:
                        remaining = ['file://' + os.path.basename(item) for
                                     item in remaining]
                        removevalues = {'SRC_URI': removedentries + remaining}
                _, destpath = oe.recipeutils.bbappend_recipe(
                                rd, args.append, files,
                                removevalues=removevalues)
            else:
                logger.info('No patches or local source files needed updating')
        else:
            # Update existing files
            for basepath, path in upd_f.iteritems():
                logger.info('Updating file %s' % basepath)
                _move_file(os.path.join(local_files_dir, basepath), path)
                updatefiles = True
            for basepath, path in upd_p.iteritems():
                patchfn = os.path.join(patches_dir, basepath)
                if changed_revs is not None:
                    # Avoid updating patches that have not actually changed
                    with open(patchfn, 'r') as f:
                        firstlineitems = f.readline().split()
                        if len(firstlineitems) > 1 and len(firstlineitems[1]) == 40:
                            if not firstlineitems[1] in changed_revs:
                                continue
                logger.info('Updating patch %s' % basepath)
                _move_file(patchfn, path)
                updatefiles = True
            # Add any new files
            files_dir = os.path.join(os.path.dirname(recipefile),
                                     rd.getVar('BPN', True))
            for basepath, path in new_f.iteritems():
                logger.info('Adding new file %s' % basepath)
                _move_file(os.path.join(local_files_dir, basepath),
                           os.path.join(files_dir, basepath))
                srcuri.append('file://%s' % basepath)
                updaterecipe = True
            for basepath, path in new_p.iteritems():
                logger.info('Adding new patch %s' % basepath)
                _move_file(os.path.join(patches_dir, basepath),
                           os.path.join(files_dir, basepath))
                srcuri.append('file://%s' % basepath)
                updaterecipe = True
            # Update recipe, if needed
            if _remove_file_entries(srcuri, remove_files)[0]:
                updaterecipe = True
            if updaterecipe:
                logger.info('Updating recipe %s' % os.path.basename(recipefile))
                oe.recipeutils.patch_recipe(rd, recipefile,
                                            {'SRC_URI': ' '.join(srcuri)})
            elif not updatefiles:
                # Neither patches nor recipe were updated
                logger.info('No patches or files need updating')
    finally:
        shutil.rmtree(tempdir)

    _remove_source_files(args, remove_files, destpath)

def _guess_recipe_update_mode(srctree, rdata):
    """Guess the recipe update mode to use"""
    src_uri = (rdata.getVar('SRC_URI', False) or '').split()
    git_uris = [uri for uri in src_uri if uri.startswith('git://')]
    if not git_uris:
        return 'patch'
    # Just use the first URI for now
    uri = git_uris[0]
    # Check remote branch
    params = bb.fetch.decodeurl(uri)[5]
    upstr_branch = params['branch'] if 'branch' in params else 'master'
    # Check if current branch HEAD is found in upstream branch
    stdout, _ = bb.process.run('git rev-parse HEAD', cwd=srctree)
    head_rev = stdout.rstrip()
    stdout, _ = bb.process.run('git branch -r --contains %s' % head_rev,
                               cwd=srctree)
    remote_brs = [branch.strip() for branch in stdout.splitlines()]
    if 'origin/' + upstr_branch in remote_brs:
        return 'srcrev'

    return 'patch'

def update_recipe(args, config, basepath, workspace):
    """Entry point for the devtool 'update-recipe' subcommand"""
    check_workspace_recipe(workspace, args.recipename)

    if args.append:
        if not os.path.exists(args.append):
            raise DevtoolError('bbappend destination layer directory "%s" '
                               'does not exist' % args.append)
        if not os.path.exists(os.path.join(args.append, 'conf', 'layer.conf')):
            raise DevtoolError('conf/layer.conf not found in bbappend '
                               'destination layer "%s"' % args.append)

    tinfoil = setup_tinfoil(basepath=basepath, tracking=True)

    rd = parse_recipe(config, tinfoil, args.recipename, True)
    if not rd:
        return 1

    srctree = workspace[args.recipename]['srctree']
    if args.mode == 'auto':
        mode = _guess_recipe_update_mode(srctree, rd)
    else:
        mode = args.mode

    if mode == 'srcrev':
        _update_recipe_srcrev(args, srctree, rd, tinfoil.config_data)
    elif mode == 'patch':
        _update_recipe_patch(args, config, srctree, rd, tinfoil.config_data)
    else:
        raise DevtoolError('update_recipe: invalid mode %s' % mode)

    rf = rd.getVar('FILE', True)
    if rf.startswith(config.workspace_path):
        logger.warn('Recipe file %s has been updated but is inside the workspace - you will need to move it (and any associated files next to it) out to the desired layer before using "devtool reset" in order to keep any changes' % rf)

    return 0


def status(args, config, basepath, workspace):
    """Entry point for the devtool 'status' subcommand"""
    if workspace:
        for recipe, value in workspace.iteritems():
            print("%s: %s" % (recipe, value['srctree']))
    else:
        logger.info('No recipes currently in your workspace - you can use "devtool modify" to work on an existing recipe or "devtool add" to add a new one')
    return 0


def reset(args, config, basepath, workspace):
    """Entry point for the devtool 'reset' subcommand"""
    import bb
    if args.recipename:
        if args.all:
            raise DevtoolError("Recipe cannot be specified if -a/--all is used")
        else:
            check_workspace_recipe(workspace, args.recipename, checksrc=False)
    elif not args.all:
        raise DevtoolError("Recipe must be specified, or specify -a/--all to "
                           "reset all recipes")
    if args.all:
        recipes = workspace.keys()
    else:
        recipes = [args.recipename]

    if recipes and not args.no_clean:
        if len(recipes) == 1:
            logger.info('Cleaning sysroot for recipe %s...' % recipes[0])
        else:
            logger.info('Cleaning sysroot for recipes %s...' % ', '.join(recipes))
        try:
            exec_build_env_command(config.init_path, basepath, 'bitbake -c clean %s' % ' '.join(recipes))
        except bb.process.ExecutionError as e:
            raise DevtoolError('Command \'%s\' failed, output:\n%s\nIf you '
                                'wish, you may specify -n/--no-clean to '
                                'skip running this command when resetting' %
                                (e.command, e.stdout))

    for pn in recipes:
        _check_preserve(config, pn)

        preservepath = os.path.join(config.workspace_path, 'attic', pn)
        def preservedir(origdir):
            if os.path.exists(origdir):
                for root, dirs, files in os.walk(origdir):
                    for fn in files:
                        logger.warn('Preserving %s in %s' % (fn, preservepath))
                        _move_file(os.path.join(origdir, fn),
                                   os.path.join(preservepath, fn))
                    for dn in dirs:
                        os.rmdir(os.path.join(root, dn))
                os.rmdir(origdir)

        preservedir(os.path.join(config.workspace_path, 'recipes', pn))
        # We don't automatically create this dir next to appends, but the user can
        preservedir(os.path.join(config.workspace_path, 'appends', pn))

    return 0


def register_commands(subparsers, context):
    """Register devtool subcommands from this plugin"""
    parser_add = subparsers.add_parser('add', help='Add a new recipe',
                                       description='Adds a new recipe')
    parser_add.add_argument('recipename', help='Name for new recipe to add')
    parser_add.add_argument('srctree', help='Path to external source tree')
    group = parser_add.add_mutually_exclusive_group()
    group.add_argument('--same-dir', '-s', help='Build in same directory as source', action="store_true")
    group.add_argument('--no-same-dir', help='Force build in a separate build directory', action="store_true")
    parser_add.add_argument('--fetch', '-f', help='Fetch the specified URI and extract it to create the source tree', metavar='URI')
    parser_add.add_argument('--version', '-V', help='Version to use within recipe (PV)')
    parser_add.add_argument('--no-git', '-g', help='If -f/--fetch is specified, do not set up source tree as a git repository', action="store_true")
    parser_add.add_argument('--binary', '-b', help='Treat the source tree as something that should be installed verbatim (no compilation, same directory structure)', action='store_true')
    parser_add.set_defaults(func=add)

    parser_modify = subparsers.add_parser('modify', help='Modify the source for an existing recipe',
                                       description='Enables modifying the source for an existing recipe',
                                       formatter_class=argparse.ArgumentDefaultsHelpFormatter)
    parser_modify.add_argument('recipename', help='Name for recipe to edit')
    parser_modify.add_argument('srctree', help='Path to external source tree')
    parser_modify.add_argument('--wildcard', '-w', action="store_true", help='Use wildcard for unversioned bbappend')
    parser_modify.add_argument('--extract', '-x', action="store_true", help='Extract source as well')
    group = parser_modify.add_mutually_exclusive_group()
    group.add_argument('--same-dir', '-s', help='Build in same directory as source', action="store_true")
    group.add_argument('--no-same-dir', help='Force build in a separate build directory', action="store_true")
    parser_modify.add_argument('--branch', '-b', default="devtool", help='Name for development branch to checkout (only when using -x)')
    parser_modify.set_defaults(func=modify)

    parser_extract = subparsers.add_parser('extract', help='Extract the source for an existing recipe',
                                       description='Extracts the source for an existing recipe',
                                       formatter_class=argparse.ArgumentDefaultsHelpFormatter)
    parser_extract.add_argument('recipename', help='Name for recipe to extract the source for')
    parser_extract.add_argument('srctree', help='Path to where to extract the source tree')
    parser_extract.add_argument('--branch', '-b', default="devtool", help='Name for development branch to checkout')
    parser_extract.add_argument('--keep-temp', action="store_true", help='Keep temporary directory (for debugging)')
    parser_extract.set_defaults(func=extract)

    parser_update_recipe = subparsers.add_parser('update-recipe', help='Apply changes from external source tree to recipe',
                                       description='Applies changes from external source tree to a recipe (updating/adding/removing patches as necessary, or by updating SRCREV)')
    parser_update_recipe.add_argument('recipename', help='Name of recipe to update')
    parser_update_recipe.add_argument('--mode', '-m', choices=['patch', 'srcrev', 'auto'], default='auto', help='Update mode (where %(metavar)s is %(choices)s; default is %(default)s)', metavar='MODE')
    parser_update_recipe.add_argument('--initial-rev', help='Starting revision for patches')
    parser_update_recipe.add_argument('--append', '-a', help='Write changes to a bbappend in the specified layer instead of the recipe', metavar='LAYERDIR')
    parser_update_recipe.add_argument('--wildcard-version', '-w', help='In conjunction with -a/--append, use a wildcard to make the bbappend apply to any recipe version', action='store_true')
    parser_update_recipe.add_argument('--no-remove', '-n', action="store_true", help='Don\'t remove patches, only add or update')
    parser_update_recipe.set_defaults(func=update_recipe)

    parser_status = subparsers.add_parser('status', help='Show workspace status',
                                          description='Lists recipes currently in your workspace and the paths to their respective external source trees',
                                          formatter_class=argparse.ArgumentDefaultsHelpFormatter)
    parser_status.set_defaults(func=status)

    parser_reset = subparsers.add_parser('reset', help='Remove a recipe from your workspace',
                                         description='Removes the specified recipe from your workspace (resetting its state)',
                                         formatter_class=argparse.ArgumentDefaultsHelpFormatter)
    parser_reset.add_argument('recipename', nargs='?', help='Recipe to reset')
    parser_reset.add_argument('--all', '-a', action="store_true", help='Reset all recipes (clear workspace)')
    parser_reset.add_argument('--no-clean', '-n', action="store_true", help='Don\'t clean the sysroot to remove recipe output')
    parser_reset.set_defaults(func=reset)