From 7531db5d7ddc92253125caafbd9f935005496bad Mon Sep 17 00:00:00 2001
From: James Ascroft-Leigh <jwal@jwal.me.uk>
Date: Sun, 22 Feb 2009 20:31:59 +0000
Subject: [PATCH] Initial version of git-meld-commit

This tool (inefficiently) shows the the changes between a commit's
tree and the parent commit(s)'s tree.  It shows the changes using meld
so the full context of the change can be seen.
---
 git-meld-commit | 101 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 101 insertions(+)
 create mode 100755 git-meld-commit

diff --git a/git-meld-commit b/git-meld-commit
new file mode 100755
index 0000000..d58da13
--- /dev/null
+++ b/git-meld-commit
@@ -0,0 +1,101 @@
+#!/usr/bin/env python
+
+# Copyright (c) 2009 James Ascroft-Leigh
+# 
+# Permission is hereby granted, free of charge, to any person
+# obtaining a copy of this software and associated documentation
+# files (the "Software"), to deal in the Software without
+# restriction, including without limitation the rights to use,
+# copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the
+# Software is furnished to do so, subject to the following
+# conditions:
+# 
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+# 
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+# OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+# OTHER DEALINGS IN THE SOFTWARE.
+
+"""\
+%prog [options] COMMIT
+
+Shows the difference between the tree from COMMIT and the tree from
+the parent of COMMIT.  Invokes meld once for each parent.
+"""
+
+# test cases:
+# initial: (cd ~/git/nacl-build && ~/git/git-meld-toys/git-meld-commit \
+#           8816f9f4ea28583d6dfa1fd96d3448977f6e2299)
+# commit: (cd ~/git/nacl-build && ~/git/git-meld-toys/git-meld-commit \
+#          707c127f621bf308f1e1a8526e79d5dc3888483c)
+# merge: (cd ~/git/git && ~/git/git-meld-toys/git-meld-commit \
+#         2d602e9179c7eb1a31a0abf41283c132e26a61af)
+
+import optparse
+import os
+import subprocess
+import shutil
+import sys
+import tempfile
+
+
+def parse_argv(prog, argv):
+    parser = optparse.OptionParser(__doc__, prog=prog)
+    options, args = parser.parse_args(argv)
+    if len(args) == 0:
+        commit_spec = "HEAD"
+    else:
+        commit_spec = args.pop(0)
+    if len(args) > 0:
+        parser.error("Unexpected: %r" % (args,))
+    return (commit_spec,)
+
+
+def dump_tree(tree_ish, destination):
+    os.mkdir(destination)
+    git = subprocess.Popen(["git", "archive", "--format=tar", tree_ish],
+                           stdout=subprocess.PIPE)
+    tar = subprocess.Popen(["tar", "-C", destination, "-x"],
+                           stdin=git.stdout)
+    tar.communicate()
+    git.communicate()
+    assert git.returncode == 0, git.returncode
+    assert tar.returncode == 0, tar.returncode
+
+
+def meld(lhs, rhs):
+    work_dir = tempfile.mkdtemp(prefix="git-meld-commit-")
+    try:
+        lhs_path = os.path.join(work_dir, "lhs", lhs)
+        rhs_path = os.path.join(work_dir, "rhs", rhs)
+        os.mkdir(os.path.dirname(lhs_path))
+        os.mkdir(os.path.dirname(rhs_path))
+        dump_tree(lhs, lhs_path)
+        dump_tree(rhs, rhs_path)
+        subprocess.check_call(["meld", lhs_path, rhs_path])
+    finally:
+        shutil.rmtree(work_dir)
+
+
+def main(commit_spec):
+    cmd = ["git", "show", "--quiet", "--pretty=format:%P", commit_spec]
+    git = subprocess.Popen(cmd, stdout=subprocess.PIPE)
+    stdout, stderr = git.communicate()
+    assert git.returncode == 0, git.returncode
+    parents = stdout.rstrip("\n").split(" ")
+    if parents == [""]:
+        parents = []
+    for parent in parents:
+        meld(commit_spec, parent)
+
+
+if __name__ == "__main__":
+    sys.exit(main(*parse_argv(sys.argv[0], sys.argv[1:])))
+
-- 
2.11.4.GIT