Speed up md5 collection of build signature calculations.

git-svn-id: http://scons.tigris.org/svn/scons/trunk@1302 fdb21ef1-2011-0410-befe-b5e4ea1792b1

diff --git a/src/engine/SCons/Sig/MD5.py b/src/engine/SCons/Sig/MD5.py
index 2adcee0998f3efe83af82f20bc9ac334779c44b7..501fec4bc311e3e5649e6348e71f257a1dd45ced 100644 (file)
--- a/src/engine/SCons/Sig/MD5.py
+++ b/src/engine/SCons/Sig/MD5.py
@@ -49,26 +49,30 @@ def current(new, old):
     """
     return new == old
 
-def hexdigest(s):
-    """Return a signature as a string of hex characters.
-    """
-    # NOTE:  This routine is a method in the Python 2.0 interface
-    # of the native md5 module, but we want SCons to operate all
-    # the way back to at least Python 1.5.2, which doesn't have it.
-    h = string.hexdigits
-    r = ''
-    for c in s:
-        i = ord(c)
-        r = r + h[(i >> 4) & 0xF] + h[i & 0xF]
-    return r
-
 try:
-    a = md5.new('test').hexdigest()
+    md5.new('').hexdigest
 except AttributeError:
-    md5sig = lambda c: hexdigest(md5.new(str(c)).digest())
-else:
-    md5sig = lambda c: md5.new(str(c)).hexdigest()
+    # The md5 objects created by the module have no native hexdigest()
+    # method (*cough* 1.5.2 *cough*) so provide an equivalent.
+    class new_md5:
+        def __init__(self, s):
+            self.m = md5.new(str(s))
+        #def copy(self):
+        #    return self.m.copy()
+        def digest(self):
+            return self.m.digest()
+        def hexdigest(self):
+            h = string.hexdigits
+            r = ''
+            for c in self.m.digest():
+                i = ord(c)
+                r = r + h[(i >> 4) & 0xF] + h[i & 0xF]
+            return r
+        def update(self, s):
+            return self.m.update(s)
 
+else:
+    new_md5 = lambda s: md5.new(str(s))
 
 def collect(signatures):
     """
@@ -78,10 +82,9 @@ def collect(signatures):
     returns - the aggregate signature
     """
     if len(signatures) == 1:
-       return signatures[0]
+        return signatures[0]
     else:
-        contents = string.join(signatures, ', ')
-       return hexdigest(md5.new(contents).digest())
+        return new_md5(string.join(signatures, ', ')).hexdigest()
 
 def signature(obj):
     """Generate a signature for an object
@@ -90,7 +93,7 @@ def signature(obj):
         gc = obj.get_contents
     except AttributeError:
         raise AttributeError, "unable to fetch contents of '%s'" % str(obj)
-    return md5sig(gc())
+    return new_md5(gc()).hexdigest()
 
 def to_string(signature):
     """Convert a signature to a string"""