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#===- git-clang-format - ClangFormat Git Integration ---------*- python -*--===#
# The LLVM Compiler Infrastructure
# This file is distributed under the University of Illinois Open Source
# License. See LICENSE.TXT for details.
clang-format git integration
This file provides a clang-format integration for git. Put it somewhere in your
path and ensure that it is executable. Then, "git clang-format" will invoke
clang-format on the changes in current files or a specific commit.
For further details, run:
git clang-format -h
Requires Python 2.7
import argparse
import collections
import contextlib
import errno
import os
import re
import subprocess
import sys
usage = 'git clang-format [OPTIONS] [<commit>] [--] [<file>...]'
desc = '''
Run clang-format on all lines that differ between the working directory
and <commit>, which defaults to HEAD. Changes are only applied to the working
The following git-config settings set the default of the corresponding option:
# Name of the temporary index file in which save the output of clang-format.
# This file is created within the .git directory.
temp_index_basename = 'clang-format-index'
Range = collections.namedtuple('Range', 'start, count')
def main():
config = load_git_config()
# In order to keep '--' yet allow options after positionals, we need to
# check for '--' ourselves. (Setting nargs='*' throws away the '--', while
# nargs=argparse.REMAINDER disallows options after positionals.)
argv = sys.argv[1:]
idx = argv.index('--')
except ValueError:
dash_dash = []
dash_dash = argv[idx:]
argv = argv[:idx]
default_extensions = ','.join([
# From clang/lib/Frontend/FrontendOptions.cpp, all lower case
'c', 'h', # C
'm', # ObjC
'mm', # ObjC++
'cc', 'cp', 'cpp', 'c++', 'cxx', 'hpp', # C++
p = argparse.ArgumentParser(
usage=usage, formatter_class=argparse.RawDescriptionHelpFormatter,
default=config.get('clangformat.binary', 'clang-format'),
help='path to clang-format'),
default=config.get('clangformat.commit', 'HEAD'),
help='default commit to use if none is specified'),
p.add_argument('--diff', action='store_true',
help='print a diff instead of applying the changes')
help=('comma-separated list of file extensions to format, '
'excluding the period and case-insensitive')),
p.add_argument('-f', '--force', action='store_true',
help='allow changes to unstaged files')
p.add_argument('-p', '--patch', action='store_true',
help='select hunks interactively')
p.add_argument('-q', '--quiet', action='count', default=0,
help='print less information')
default=config.get('', None),
help='passed to clang-format'),
p.add_argument('-v', '--verbose', action='count', default=0,
help='print extra information')
# We gather all the remaining positional arguments into 'args' since we need
# to use some heuristics to determine whether or not <commit> was present.
# However, to print pretty messages, we make use of metavar and help.
p.add_argument('args', nargs='*', metavar='<commit>',
help='revision from which to compute the diff')
p.add_argument('ignored', nargs='*', metavar='<file>...',
help='if specified, only consider differences in these files')
opts = p.parse_args(argv)
opts.verbose -= opts.quiet
del opts.quiet
commit, files = interpret_args(opts.args, dash_dash, opts.commit)
changed_lines = compute_diff_and_extract_lines(commit, files)
if opts.verbose >= 1:
ignored_files = set(changed_lines)
filter_by_extension(changed_lines, opts.extensions.lower().split(','))
if opts.verbose >= 1:
if ignored_files:
print 'Ignoring changes in the following files (wrong extension):'
for filename in ignored_files:
print ' ', filename
if changed_lines:
print 'Running clang-format on the following files:'
for filename in changed_lines:
print ' ', filename
if not changed_lines:
print 'no modified files to format'
# The computed diff outputs absolute paths, so we must cd before accessing
# those files.
old_tree = create_tree_from_workdir(changed_lines)
new_tree = run_clang_format_and_save_to_tree(changed_lines,
if opts.verbose >= 1:
print 'old tree:', old_tree
print 'new tree:', new_tree
if old_tree == new_tree:
if opts.verbose >= 0:
print 'clang-format did not modify any files'
elif opts.diff:
print_diff(old_tree, new_tree)
changed_files = apply_changes(old_tree, new_tree, force=opts.force,
if (opts.verbose >= 0 and not opts.patch) or opts.verbose >= 1:
print 'changed files:'
for filename in changed_files:
print ' ', filename
def load_git_config(non_string_options=None):
"""Return the git configuration as a dictionary.
All options are assumed to be strings unless in `non_string_options`, in which
is a dictionary mapping option name (in lower case) to either "--bool" or
if non_string_options is None:
non_string_options = {}
out = {}
for entry in run('git', 'config', '--list', '--null').split('\0'):
if entry:
name, value = entry.split('\n', 1)
if name in non_string_options:
value = run('git', 'config', non_string_options[name], name)
out[name] = value
return out
def interpret_args(args, dash_dash, default_commit):
"""Interpret `args` as "[commit] [--] [files...]" and return (commit, files).
It is assumed that "--" and everything that follows has been removed from
args and placed in `dash_dash`.
If "--" is present (i.e., `dash_dash` is non-empty), the argument to its
left (if present) is taken as commit. Otherwise, the first argument is
checked if it is a commit or a file. If commit is not given,
`default_commit` is used."""
if dash_dash:
if len(args) == 0:
commit = default_commit
elif len(args) > 1:
die('at most one commit allowed; %d given' % len(args))
commit = args[0]
object_type = get_object_type(commit)
if object_type not in ('commit', 'tag'):
if object_type is None:
die("'%s' is not a commit" % commit)
die("'%s' is a %s, but a commit was expected" % (commit, object_type))
files = dash_dash[1:]
elif args:
if disambiguate_revision(args[0]):
commit = args[0]
files = args[1:]
commit = default_commit
files = args
commit = default_commit
files = []
return commit, files
def disambiguate_revision(value):
"""Returns True if `value` is a revision, False if it is a file, or dies."""
# If `value` is ambiguous (neither a commit nor a file), the following
# command will die with an appropriate error message.
run('git', 'rev-parse', value, verbose=False)
object_type = get_object_type(value)
if object_type is None:
return False
if object_type in ('commit', 'tag'):
return True
die('`%s` is a %s, but a commit or filename was expected' %
(value, object_type))
def get_object_type(value):
"""Returns a string description of an object's type, or None if it is not
a valid git object."""
cmd = ['git', 'cat-file', '-t', value]
p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
stdout, stderr = p.communicate()
if p.returncode != 0:
return None
return stdout.strip()
def compute_diff_and_extract_lines(commit, files):
"""Calls compute_diff() followed by extract_lines()."""
diff_process = compute_diff(commit, files)
changed_lines = extract_lines(diff_process.stdout)
if diff_process.returncode != 0:
# Assume error was already printed to stderr.
return changed_lines
def compute_diff(commit, files):
"""Return a subprocess object producing the diff from `commit`.
The return value's `stdin` file object will produce a patch with the
differences between the working directory and `commit`, filtered on `files`
(if non-empty). Zero context lines are used in the patch."""
cmd = ['git', 'diff-index', '-p', '-U0', commit, '--']
p = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
return p
def extract_lines(patch_file):
"""Extract the changed lines in `patch_file`.
The return value is a dictionary mapping filename to a list of (start_line,
line_count) pairs.
The input must have been produced with ``-U0``, meaning unidiff format with
zero lines of context. The return value is a dict mapping filename to a
list of line `Range`s."""
matches = {}
for line in patch_file:
match ='^\+\+\+\ [^/]+/(.*)', line)
if match:
filename ='\r\n')
match ='^@@ -[0-9,]+ \+(\d+)(,(\d+))?', line)
if match:
start_line = int(
line_count = 1
line_count = int(
if line_count > 0:
matches.setdefault(filename, []).append(Range(start_line, line_count))
return matches
def filter_by_extension(dictionary, allowed_extensions):
"""Delete every key in `dictionary` that doesn't have an allowed extension.
`allowed_extensions` must be a collection of lowercase file extensions,
excluding the period."""
allowed_extensions = frozenset(allowed_extensions)
for filename in dictionary.keys():
base_ext = filename.rsplit('.', 1)
if len(base_ext) == 1 or base_ext[1].lower() not in allowed_extensions:
del dictionary[filename]
def cd_to_toplevel():
"""Change to the top level of the git repository."""
toplevel = run('git', 'rev-parse', '--show-toplevel')
def create_tree_from_workdir(filenames):
"""Create a new git tree with the given files from the working directory.
Returns the object ID (SHA-1) of the created tree."""
return create_tree(filenames, '--stdin')
def run_clang_format_and_save_to_tree(changed_lines, binary='clang-format',
"""Run clang-format on each file and save the result to a git tree.
Returns the object ID (SHA-1) of the created tree."""
def index_info_generator():
for filename, line_ranges in changed_lines.iteritems():
mode = oct(os.stat(filename).st_mode)
blob_id = clang_format_to_blob(filename, line_ranges, binary=binary,
yield '%s %s\t%s' % (mode, blob_id, filename)
return create_tree(index_info_generator(), '--index-info')
def create_tree(input_lines, mode):
"""Create a tree object from the given input.
If mode is '--stdin', it must be a list of filenames. If mode is
'--index-info' is must be a list of values suitable for "git update-index
--index-info", such as "<mode> <SP> <sha1> <TAB> <filename>". Any other mode
is invalid."""
assert mode in ('--stdin', '--index-info')
cmd = ['git', 'update-index', '--add', '-z', mode]
with temporary_index_file():
p = subprocess.Popen(cmd, stdin=subprocess.PIPE)
for line in input_lines:
p.stdin.write('%s\0' % line)
if p.wait() != 0:
die('`%s` failed' % ' '.join(cmd))
tree_id = run('git', 'write-tree')
return tree_id
def clang_format_to_blob(filename, line_ranges, binary='clang-format',
"""Run clang-format on the given file and save the result to a git blob.
Returns the object ID (SHA-1) of the created blob."""
clang_format_cmd = [binary, filename]
if style:
'-lines=%s:%s' % (start_line, start_line+line_count-1)
for start_line, line_count in line_ranges])
clang_format = subprocess.Popen(clang_format_cmd, stdin=subprocess.PIPE,
except OSError as e:
if e.errno == errno.ENOENT:
die('cannot find executable "%s"' % binary)
hash_object_cmd = ['git', 'hash-object', '-w', '--path='+filename, '--stdin']
hash_object = subprocess.Popen(hash_object_cmd, stdin=clang_format.stdout,
stdout = hash_object.communicate()[0]
if hash_object.returncode != 0:
die('`%s` failed' % ' '.join(hash_object_cmd))
if clang_format.wait() != 0:
die('`%s` failed' % ' '.join(clang_format_cmd))
return stdout.rstrip('\r\n')
def temporary_index_file(tree=None):
"""Context manager for setting GIT_INDEX_FILE to a temporary file and deleting
the file afterward."""
index_path = create_temporary_index(tree)
old_index_path = os.environ.get('GIT_INDEX_FILE')
os.environ['GIT_INDEX_FILE'] = index_path
if old_index_path is None:
del os.environ['GIT_INDEX_FILE']
os.environ['GIT_INDEX_FILE'] = old_index_path
def create_temporary_index(tree=None):
"""Create a temporary index file and return the created file's path.
If `tree` is not None, use that as the tree to read in. Otherwise, an
empty index is created."""
gitdir = run('git', 'rev-parse', '--git-dir')
path = os.path.join(gitdir, temp_index_basename)
if tree is None:
tree = '--empty'
run('git', 'read-tree', '--index-output='+path, tree)
return path
def print_diff(old_tree, new_tree):
"""Print the diff between the two trees to stdout."""
# We use the porcelain 'diff' and not plumbing 'diff-tree' because the output
# is expected to be viewed by the user, and only the former does nice things
# like color and pagination.
subprocess.check_call(['git', 'diff', old_tree, new_tree, '--'])
def apply_changes(old_tree, new_tree, force=False, patch_mode=False):
"""Apply the changes in `new_tree` to the working directory.
Bails if there are local changes in those files and not `force`. If
`patch_mode`, runs `git checkout --patch` to select hunks interactively."""
changed_files = run('git', 'diff-tree', '-r', '-z', '--name-only', old_tree,
if not force:
unstaged_files = run('git', 'diff-files', '--name-status', *changed_files)
if unstaged_files:
print >>sys.stderr, ('The following files would be modified but '
'have unstaged changes:')
print >>sys.stderr, unstaged_files
print >>sys.stderr, 'Please commit, stage, or stash them first.'
if patch_mode:
# In patch mode, we could just as well create an index from the new tree
# and checkout from that, but then the user will be presented with a
# message saying "Discard ... from worktree". Instead, we use the old
# tree as the index and checkout from new_tree, which gives the slightly
# better message, "Apply ... to index and worktree". This is not quite
# right, since it won't be applied to the user's index, but oh well.
with temporary_index_file(old_tree):
subprocess.check_call(['git', 'checkout', '--patch', new_tree])
index_tree = old_tree
with temporary_index_file(new_tree):
run('git', 'checkout-index', '-a', '-f')
return changed_files
def run(*args, **kwargs):
stdin = kwargs.pop('stdin', '')
verbose = kwargs.pop('verbose', True)
strip = kwargs.pop('strip', True)
for name in kwargs:
raise TypeError("run() got an unexpected keyword argument '%s'" % name)
p = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
stdout, stderr = p.communicate(input=stdin)
if p.returncode == 0:
if stderr:
if verbose:
print >>sys.stderr, '`%s` printed to stderr:' % ' '.join(args)
print >>sys.stderr, stderr.rstrip()
if strip:
stdout = stdout.rstrip('\r\n')
return stdout
if verbose:
print >>sys.stderr, '`%s` returned %s' % (' '.join(args), p.returncode)
if stderr:
print >>sys.stderr, stderr.rstrip()
def die(message):
print >>sys.stderr, 'error:', message
if __name__ == '__main__':