Merge branch 'index' into improvements

* index:
  Removed index test marker for custom commits as this boils down to a good way to add files to the index/remove them and make commits which are possibly customized with custom parents
  index writing now creates a sha on the content making it possible to write valid indices after manually removing or altering entriesgst
  Implemented merge/resolve handling , but realized that index writing is not yet working properly as it is sha1 checked as well. This explains what my 20 byte 'extension_data' actually is ;)
  index: Added write_tree method including test
  index.iter_blobs method added including tests ( which have been improved generally for more coverage )
  tree.traverse: Added prune functionality - previously the predciate did both, pruning and preventing to return items
  Improved testing of index against trees, tests succeed with next commit
  Initial version of merge including tests for one-way, two-way and tree-way merge
  index writing added including simple test, improved docs of IndexEntry
  improved IndexEntry type and added test for parsing of the stage
  Improved tuple access of EntryIndex class including test, stage and type access still needs to be decoded though
  Added initial version of the index reading from file - IndexEntry interface is to be improved though, writing needs to be implemented as well
  Added frame for index implementation and testing

1 files changed, 52 insertions, 0 deletions

diff --git a/lib/git/utils.py b/lib/git/utils.py
index 2aa8d33e..cdc7c55b 100644
--- a/lib/git/utils.py
+++ b/lib/git/utils.py
@@ -6,6 +6,58 @@
 
 import os
 
+try:
+    import hashlib
+except ImportError:
+    import sha
+
+def make_sha(source=''):
+    """
+    A python2.4 workaround for the sha/hashlib module fiasco
+    
+	Note
+		From the dulwich project
+	"""
+    try:
+        return hashlib.sha1(source)
+    except NameError:
+        sha1 = sha.sha(source)
+        return sha1
+
+
+class SHA1Writer(object):
+    """
+    Wrapper around a file-like object that remembers the SHA1 of 
+    the data written to it. It will write a sha when the stream is closed
+    or if the asked for explicitly usign write_sha.
+    
+    Note:
+    	Based on the dulwich project
+    """
+    __slots__ = ("f", "sha1")
+    
+    def __init__(self, f):
+        self.f = f
+        self.sha1 = make_sha("")
+
+    def write(self, data):
+        self.sha1.update(data)
+        self.f.write(data)
+
+    def write_sha(self):
+        sha = self.sha1.digest()
+        self.f.write(sha)
+        return sha
+
+    def close(self):
+        sha = self.write_sha()
+        self.f.close()
+        return sha
+
+    def tell(self):
+        return self.f.tell()
+
+
 class LazyMixin(object):
 	"""
 	Base class providing an interface to lazily retrieve attribute values upon