recipetool: add appendfile subcommand

Locating which recipe provides a file in an image that you want to
modify and then figuring out how to bbappend the recipe in order to
replace it can be a tedious process. Thus, add a new appendfile
subcommand to recipetool, providing the ability to create a bbappend
file to add/replace any file in the target system. Without the -r
option, it will search for the recipe packaging the specified file
(using pkgdata from previously built recipes). The bbappend will be
created at the appropriate path within the specified layer directory
(which may or may not be in your bblayers.conf) or if one already exists
it will be updated appropriately.

Fairly extensive oe-selftest tests are also provided.

Implements [YOCTO #6447].

(From OE-Core rev: dd2aa93b3c13d2c6464ef0fda59620c7dba450bb)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oe/patch.py

@@ -92,6 +92,69 @@ class PatchSet(object):
     def Refresh(self, remote = None, all = None):
         raise NotImplementedError()
 
+    @staticmethod
+    def getPatchedFiles(patchfile, striplevel, srcdir=None):
+        """
+        Read a patch file and determine which files it will modify.
+        Params:
+            patchfile: the patch file to read
+            striplevel: the strip level at which the patch is going to be applied
+            srcdir: optional path to join onto the patched file paths
+        Returns:
+            A list of tuples of file path and change mode ('A' for add,
+            'D' for delete or 'M' for modify)
+        """
+
+        def patchedpath(patchline):
+            filepth = patchline.split()[1]
+            if filepth.endswith('/dev/null'):
+                return '/dev/null'
+            filesplit = filepth.split(os.sep)
+            if striplevel > len(filesplit):
+                bb.error('Patch %s has invalid strip level %d' % (patchfile, striplevel))
+                return None
+            return os.sep.join(filesplit[striplevel:])
+
+        copiedmode = False
+        filelist = []
+        with open(patchfile) as f:
+            for line in f:
+                if line.startswith('--- '):
+                    patchpth = patchedpath(line)
+                    if not patchpth:
+                        break
+                    if copiedmode:
+                        addedfile = patchpth
+                    else:
+                        removedfile = patchpth
+                elif line.startswith('+++ '):
+                    addedfile = patchedpath(line)
+                    if not addedfile:
+                        break
+                elif line.startswith('*** '):
+                    copiedmode = True
+                    removedfile = patchedpath(line)
+                    if not removedfile:
+                        break
+                else:
+                    removedfile = None
+                    addedfile = None
+
+                if addedfile and removedfile:
+                    if removedfile == '/dev/null':
+                        mode = 'A'
+                    elif addedfile == '/dev/null':
+                        mode = 'D'
+                    else:
+                        mode = 'M'
+                    if srcdir:
+                        fullpath = os.path.abspath(os.path.join(srcdir, addedfile))
+                    else:
+                        fullpath = addedfile
+                    filelist.append((fullpath, mode))
+
+        return filelist
+
 
 class PatchTree(PatchSet):
     def __init__(self, dir, d):