diff mercurial/revlog.py @ 37442:0596d27457c6

revlog: move parsemeta() and packmeta() from filelog (API)

filelog.parsemeta() and filelog.packmeta() are used to decode
and encode metadata for file copies and censor.

An upcoming commit will move the core logic for censoring revlogs
into revlog.py. This would create a cycle between revlog.py and
filelog.py. So we move these metadata functions to revlog.py.

.. api::

   filelog.parsemeta() and filelog.packmeta() have been moved to
   the revlog module.

Differential Revision: https://phab.mercurial-scm.org/D3150

--- a/mercurial/revlog.py	Thu Apr 05 15:18:23 2018 -0700
+++ b/mercurial/revlog.py	Thu Apr 05 18:22:35 2018 -0700
@@ -19,6 +19,7 @@
 import hashlib
 import heapq
 import os
+import re
 import struct
 import zlib
 
@@ -97,6 +98,25 @@
     REVIDX_ISCENSORED: None,
 }
 
+_mdre = re.compile('\1\n')
+def parsemeta(text):
+    """return (metadatadict, metadatasize)"""
+    # text can be buffer, so we can't use .startswith or .index
+    if text[:2] != '\1\n':
+        return None, None
+    s = _mdre.search(text, 2).start()
+    mtext = text[2:s]
+    meta = {}
+    for l in mtext.splitlines():
+        k, v = l.split(": ", 1)
+        meta[k] = v
+    return meta, (s + 2)
+
+def packmeta(meta, text):
+    keys = sorted(meta)
+    metatext = "".join("%s: %s\n" % (k, meta[k]) for k in keys)
+    return "\1\n%s\1\n%s" % (metatext, text)
+
 def addflagprocessor(flag, processor):
     """Register a flag processor on a revision data flag.