bitbake: layerindexlib: Initial layer index processing module implementation

The layer index module is expected to be used by various parts of the system
in order to access a layerindex-web (such as layers.openembedded.org) and
perform basic processing on the information, such as dependency scanning.

Along with the layerindex implementation are associated tests.  The tests
properly honor BB_SKIP_NETTESTS='yes' to prevent test failures.

Tests Implemented:
   - Branch, LayerItem, LayerBranch, LayerDependency, Recipe, Machine and
      Distro objects
   - LayerIndex setup using the layers.openembedded.org restapi
   - LayerIndex storing and retrieving from a file
   - LayerIndex verify dependency resolution ordering
   - LayerIndex setup using simulated cooker data

(Bitbake rev: fd0ee6c10dbb5592731e56f4c592fe687682a3e6)

Signed-off-by: Mark Hatle <mark.hatle@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/layerindexlib/plugin.py

@@ -0,0 +1,60 @@
+# Copyright (C) 2016-2018 Wind River Systems, Inc.
+#
+# 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+# The file contains:
+#   LayerIndex exceptions
+#   Plugin base class
+#   Utility Functions for working on layerindex data
+
+import argparse
+import logging
+import os
+import bb.msg
+
+logger = logging.getLogger('BitBake.layerindexlib.plugin')
+
+class LayerIndexPluginException(Exception):
+    """LayerIndex Generic Exception"""
+    def __init__(self, message):
+         self.msg = message
+         Exception.__init__(self, message)
+
+    def __str__(self):
+         return self.msg
+
+class LayerIndexPluginUrlError(LayerIndexPluginException):
+    """Exception raised when a plugin does not support a given URL type"""
+    def __init__(self, plugin, url):
+        msg = "%s does not support %s:" % (plugin, url)
+        self.plugin = plugin
+        self.url = url
+        LayerIndexPluginException.__init__(self, msg)
+
+class IndexPlugin():
+    def __init__(self):
+        self.type = None
+
+    def init(self, layerindex):
+        self.layerindex = layerindex
+
+    def plugin_type(self):
+        return self.type
+
+    def load_index(self, uri):
+        raise NotImplementedError('load_index is not implemented')
+
+    def store_index(self, uri, index):
+        raise NotImplementedError('store_index is not implemented')
+