bitbake: bitbake-layers: convert to plugin-based

This uses bb.utils.load_plugins, based on the plugin handling in recipetool
and devtool in oe-core.

(Bitbake rev: 5e542df9b966a99b5a5b8aa7cf6100174aff54b2)

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bblayers/common.py

@@ -0,0 +1,33 @@
+import argparse
+import logging
+import os
+
+logger = logging.getLogger('bitbake-layers')
+
+
+class LayerPlugin():
+    def __init__(self):
+        self.tinfoil = None
+        self.bblayers = []
+
+    def tinfoil_init(self, tinfoil):
+        self.tinfoil = tinfoil
+        self.bblayers = (self.tinfoil.config_data.getVar('BBLAYERS', True) or "").split()
+        layerconfs = self.tinfoil.config_data.varhistory.get_variable_items_files('BBFILE_COLLECTIONS', self.tinfoil.config_data)
+        self.bbfile_collections = {layer: os.path.dirname(os.path.dirname(path)) for layer, path in layerconfs.iteritems()}
+
+    @staticmethod
+    def add_command(subparsers, cmdname, function, parserecipes=True, *args, **kwargs):
+        """Convert docstring for function to help."""
+        docsplit = function.__doc__.splitlines()
+        help = docsplit[0]
+        if len(docsplit) > 1:
+            desc = '\n'.join(docsplit[1:])
+        else:
+            desc = help
+        subparser = subparsers.add_parser(cmdname, *args, help=help, description=desc, formatter_class=argparse.RawTextHelpFormatter, **kwargs)
+        subparser.set_defaults(func=function, parserecipes=parserecipes)
+        return subparser
+
+    def get_layer_name(self, layerdir):
+        return os.path.basename(layerdir.rstrip(os.sep))