patch: extract and rename gitpatch into patchmeta, document

mercurial/patch.py

@@ -143,10 +143,14 b' GP_PATCH = 1 << 0 # we have to run pat'
 GP_FILTER = 1 << 1  # there's some copy/rename operation
 GP_BINARY = 1 << 2  # there's a binary patch
 
-def readgitpatch(fp, firstline=None):
-    """extract git-style metadata about patches from <patchname>"""
-    class gitpatch:
-        "op is one of ADD, DELETE, RENAME, MODIFY or COPY"
+class patchmeta:
+    """Patched file metadata
+
+    'op' is the performed operation within ADD, DELETE, RENAME, MODIFY
+    or COPY.  'path' is patched file path. 'oldpath' is set to the
+    origin file when 'op' is either COPY or RENAME, None
+    otherwise. 'mode' is set to the new mode of patched file or None.
+    """
         def __init__(self, path):
             self.path = path
             self.oldpath = None
@@ -155,6 +159,9 b' def readgitpatch(fp, firstline=None):'
             self.lineno = 0
             self.binary = False
 
+def readgitpatch(fp, firstline=None):
+    """extract git-style metadata about patches from <patchname>"""
+
     def reader(fp, firstline):
         if firstline is not None:
             yield firstline
@@ -177,7 +184,7 b' def readgitpatch(fp, firstline=None):'
                 if gp:
                     gitpatches.append(gp)
                 src, dst = m.group(1, 2)
-                gp = gitpatch(dst)
+                gp = patchmeta(dst)
                 gp.lineno = lineno
         elif gp:
             if line.startswith('--- '):