sensors: split building from manager object

To increase testability, split out the building of sensors
from the sensor manager.  And this further splits out building
from a configuration file.

Tested: Verified code continued to build and link.
Tested: Ran on quanta-q71l board and it behaved as expected.

Change-Id: Ib63a11e1107b1864c3c370bba2bd9ef2effa42f3
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/sensors/builderconfig.cpp b/sensors/builderconfig.cpp
new file mode 100644
index 0000000..b3507ae
--- /dev/null
+++ b/sensors/builderconfig.cpp
@@ -0,0 +1,114 @@
+/**
+ * Copyright 2017 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <iostream>
+#include <libconfig.h++>
+
+/* Configuration. */
+#include "conf.hpp"
+
+#include "sensors/builder.hpp"
+#include "sensors/manager.hpp"
+
+/*
+ * If there's a configuration file, we build from that, and it requires special
+ * parsing.  I should just ditch the compile-time version to reduce the
+ * probability of sync bugs.
+ */
+std::shared_ptr<SensorManager> BuildSensorsFromConfig(const std::string& path)
+{
+    using namespace libconfig;
+
+    std::map<std::string, struct sensor> config;
+    Config cfg;
+
+    std::cerr << "entered BuildSensorsFromConfig\n";
+
+    /* The load was modeled after the example source provided. */
+    try
+    {
+        cfg.readFile(path.c_str());
+    }
+    catch (const FileIOException& fioex)
+    {
+        std::cerr << "I/O error while reading file: " << fioex.what() << std::endl;
+        throw;
+    }
+    catch (const ParseException& pex)
+    {
+        std::cerr << "Parse error at " << pex.getFile() << ":" << pex.getLine()
+                  << " - " << pex.getError() << std::endl;
+        throw;
+    }
+
+    try
+    {
+        const Setting& root = cfg.getRoot();
+
+        /* Grab the list of sensors and create them all */
+        const Setting& sensors = root["sensors"];
+        int count = sensors.getLength();
+
+        for (int i = 0; i < count; ++i)
+        {
+            const Setting& sensor = sensors[i];
+
+            std::string name;
+            struct sensor thisOne;
+
+            /* Not a super fan of using this library for run-time configuration. */
+            name = sensor.lookup("name").c_str();
+            thisOne.type = sensor.lookup("type").c_str();
+            thisOne.readpath = sensor.lookup("readpath").c_str();
+            thisOne.writepath = sensor.lookup("writepath").c_str();
+
+            /* TODO: Document why this is wonky.  The library probably doesn't
+             * like int64_t
+             */
+            int min = sensor.lookup("min");
+            thisOne.min = static_cast<int64_t>(min);
+            int max = sensor.lookup("max");
+            thisOne.max = static_cast<int64_t>(max);
+            int timeout = sensor.lookup("timeout");
+            thisOne.timeout = static_cast<int64_t>(timeout);
+
+            // leaving for verification for now.  and yea the above is
+            // necessary.
+            std::cerr << "min: " << min
+                    << " max: " << max
+                    << " savedmin: " << thisOne.min
+                    << " savedmax: " << thisOne.max
+                    << " timeout: " << thisOne.timeout
+                    << std::endl;
+
+            config[name] = thisOne;
+        }
+    }
+    catch (const SettingTypeException &setex)
+    {
+        std::cerr << "Setting '" << setex.getPath()
+                  << "' type exception!" << std::endl;
+        throw;
+    }
+    catch (const SettingNotFoundException& snex)
+    {
+        std::cerr << "Setting not found!" << std::endl;
+        throw;
+    }
+
+    return BuildSensors(config);
+}
+