IndexFile.commit() now runs pre-commit and post-commit hooks.

However, it does so only on posix. The test-case will run on posix only
as well.
Please note that in theory, even on windows we will attempt to run hooks,
even though I am not sure that this will actually work.

Fixes #81

2 files changed, 50 insertions, 5 deletions

diff --git a/git/index/base.py b/git/index/base.py
index db0c3cda..7002385c 100644
--- a/git/index/base.py
+++ b/git/index/base.py
@@ -63,7 +63,8 @@ from .fun import (
     aggressive_tree_merge,
     write_tree_from_cache,
     stat_mode_to_index_mode,
-    S_IFGITLINK
+    S_IFGITLINK,
+    run_commit_hook
 )
 
 from gitdb.base import IStream
@@ -893,9 +894,12 @@ class IndexFile(LazyMixin, diff.Diffable, Serializable):
         :note: If you have manually altered the .entries member of this instance,
                don't forget to write() your changes to disk beforehand.
         :return: Commit object representing the new commit"""
+        run_commit_hook('pre-commit', self)
         tree = self.write_tree()
-        return Commit.create_from_tree(self.repo, tree, message, parent_commits,
+        rval = Commit.create_from_tree(self.repo, tree, message, parent_commits,
                                        head, author=author, committer=committer)
+        run_commit_hook('post-commit', self)
+        return rval
 
     @classmethod
     def _flush_stdin_and_wait(cls, proc, ignore_stdout=False):
diff --git a/git/index/fun.py b/git/index/fun.py
index f0dee961..38ad843b 100644
--- a/git/index/fun.py
+++ b/git/index/fun.py
@@ -13,9 +13,14 @@ from stat import (
 S_IFGITLINK = S_IFLNK | S_IFDIR     # a submodule
 
 from io import BytesIO
+import os
+import subprocess
 
 from git.util import IndexFileSHA1Writer
-from git.exc import UnmergedEntriesError
+from git.exc import (
+    UnmergedEntriesError,
+    HookExecutionError
+)
 from git.objects.fun import (
     tree_to_stream,
     traverse_tree_recursive,
@@ -37,10 +42,46 @@ from .util import (
 
 from gitdb.base import IStream
 from gitdb.typ import str_tree_type
-from git.compat import defenc
+from git.compat import (
+    defenc,
+    force_text
+)
 
 __all__ = ('write_cache', 'read_cache', 'write_tree_from_cache', 'entry_key',
-           'stat_mode_to_index_mode', 'S_IFGITLINK')
+           'stat_mode_to_index_mode', 'S_IFGITLINK', 'run_commit_hook', 'hook_path')
+
+
+def hook_path(name, git_dir):
+    """:return: path to the given named hook in the given git repository directory"""
+    return os.path.join(git_dir, 'hooks', name)
+
+
+def run_commit_hook(name, index):
+    """Run the commit hook of the given name. Silently ignores hooks that do not exist.
+    :param name: name of hook, like 'pre-commit'
+    :param index: IndexFile instance
+    :raises HookExecutionError: """
+    hp = hook_path(name, index.repo.git_dir)
+    if not os.access(hp, os.X_OK):
+        return
+
+    env = os.environ.copy()
+    env['GIT_INDEX_FILE'] = index.path
+    env['GIT_EDITOR'] = ':'
+    cmd = subprocess.Popen(hp,
+                           env=env,
+                           stdout=subprocess.PIPE,
+                           stderr=subprocess.PIPE,
+                           close_fds=(os.name == 'posix'))
+    stdout, stderr = cmd.communicate()
+    cmd.stdout.close()
+    cmd.stderr.close()
+
+    if cmd.returncode != 0:
+        stdout = force_text(stdout, defenc)
+        stderr = force_text(stderr, defenc)
+        raise HookExecutionError(hp, cmd.returncode, stdout, stderr)
+    # end handle return code
 
 
 def stat_mode_to_index_mode(mode):