[PATCH 1 of 4] revlog: move compress method outside revlog class

[Wojciech Lopata]

# HG changeset patch
# User Wojciech Lopata <lopek at fb.com>
# Date 1380209082 25200
#      Thu Sep 26 08:24:42 2013 -0700
# Node ID 54ae55d8365d44a5bc8404311531f380c9fd5ad5
# Parent  c80feeb715d1ebe9232c00881d43c1bbb594b3fa
revlog: move compress method outside revlog class

diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -75,6 +75,35 @@
     s.update(text)
     return s.digest()
 
+def compress(text):
+    """ generate a possibly-compressed representation of text """
+    if not text:
+        return ("", text)
+    l = len(text)
+    bin = None
+    if l < 44:
+        pass
+    elif l > 1000000:
+        # zlib makes an internal copy, thus doubling memory usage for
+        # large files, so lets do this in pieces
+        z = zlib.compressobj()
+        p = []
+        pos = 0
+        while pos < l:
+            pos2 = pos + 2**20
+            p.append(z.compress(text[pos:pos2]))
+            pos = pos2
+        p.append(z.flush())
+        if sum(map(len, p)) < l:
+            bin = "".join(p)
+    else:
+        bin = _compress(text)
+    if bin is None or len(bin) > l:
+        if text[0] == '\0':
+            return ("", text)
+        return ('u', text)
+    return ("", bin)
+
 def decompress(bin):
     """ decompress the given input """
     if not bin:
@@ -1053,35 +1082,6 @@
                 dfh.close()
             ifh.close()
 
-    def compress(self, text):
-        """ generate a possibly-compressed representation of text """
-        if not text:
-            return ("", text)
-        l = len(text)
-        bin = None
-        if l < 44:
-            pass
-        elif l > 1000000:
-            # zlib makes an internal copy, thus doubling memory usage for
-            # large files, so lets do this in pieces
-            z = zlib.compressobj()
-            p = []
-            pos = 0
-            while pos < l:
-                pos2 = pos + 2**20
-                p.append(z.compress(text[pos:pos2]))
-                pos = pos2
-            p.append(z.flush())
-            if sum(map(len, p)) < l:
-                bin = "".join(p)
-        else:
-            bin = _compress(text)
-        if bin is None or len(bin) > l:
-            if text[0] == '\0':
-                return ("", text)
-            return ('u', text)
-        return ("", bin)
-
     def _addrevision(self, node, text, transaction, link, p1, p2,
                      cachedelta, ifh, dfh):
         """internal function to add revisions to the log
@@ -1112,7 +1112,7 @@
                 t = buildtext()
                 ptext = self.revision(self.node(rev))
                 delta = mdiff.textdiff(ptext, t)
-            data = self.compress(delta)
+            data = compress(delta)
             l = len(data[1]) + len(data[0])
             if basecache[0] == rev:
                 chainbase = basecache[1]
@@ -1158,7 +1158,7 @@
             textlen = len(text)
         if d is None or dist > textlen * 2:
             text = buildtext()
-            data = self.compress(text)
+            data = compress(text)
             l = len(data[1]) + len(data[0])
             base = chainbase = curr