diff mercurial/utils/storageutil.py @ 39880:1b65fb4d43d6

storageutil: new function for extracting metadata-less content from text

Other storage backends will want to do this.

I'm not concerned about Python function call overhead because I
expect self.revision() to dwarf the function call overhead time,
since self.revision() requires multiple function calls and may
involve decompression in the common case.

Differential Revision: https://phab.mercurial-scm.org/D4756

--- a/mercurial/utils/storageutil.py	Mon Sep 24 14:33:45 2018 -0700
+++ b/mercurial/utils/storageutil.py	Mon Sep 24 14:54:28 2018 -0700
@@ -69,3 +69,15 @@
 def iscensoredtext(text):
     meta = parsemeta(text)[0]
     return meta and b'censored' in meta
+
+def filtermetadata(text):
+    """Extract just the revision data from source text.
+
+    Returns ``text`` unless it has a metadata header, in which case we return
+    a new buffer without hte metadata.
+    """
+    if not text.startswith(b'\x01\n'):
+        return text
+
+    offset = text.index(b'\x01\n', 2)
+    return text[offset + 2:]