cola/git.py

   1 from __future__ import division, absolute_import, unicode_literals
   2 from functools import partial
   3 import errno
   4 import os
   5 from os.path import join
   6 import subprocess
   7 import threading
   8
   9 from . import core
  10 from .compat import int_types
  11 from .compat import ustr
  12 from .compat import WIN32
  13 from .decorators import memoize
  14 from .interaction import Interaction
  15
  16
  17 GIT_COLA_TRACE = core.getenv('GIT_COLA_TRACE', '')
  18 GIT = core.getenv('GIT_COLA_GIT', 'git')
  19 STATUS = 0
  20 STDOUT = 1
  21 STDERR = 2
  22
  23 # Object ID / SHA1-related constants
  24 # Git's empty tree is a built-in constant object name.
  25 EMPTY_TREE_OID = '4b825dc642cb6eb9a060e54bf8d69288fbee4904'
  26 # Git's diff machinery returns zeroes for modified files whose content exists
  27 # in the worktree only.
  28 MISSING_BLOB_OID = '0000000000000000000000000000000000000000'
  29 # Git's SHA-1 object IDs are 40 characters  long.
  30 # This will need to change when Git moves away from SHA-1.
  31 # When that happens we'll have to detect and update this at runtime in
  32 # order to support both old and new git.
  33 OID_LENGTH = 40
  34
  35 _index_lock = threading.Lock()
  36
  37
  38 def dashify(s):
  39     return s.replace('_', '-')
  40
  41
  42 def is_git_dir(git_dir):
  43     """From git's setup.c:is_git_directory()."""
  44     result = False
  45     if git_dir:
  46         headref = join(git_dir, 'HEAD')
  47
  48         if (
  49             core.isdir(git_dir)
  50             and (
  51                 core.isdir(join(git_dir, 'objects'))
  52                 and core.isdir(join(git_dir, 'refs'))
  53             )
  54             or (
  55                 core.isfile(join(git_dir, 'gitdir'))
  56                 and core.isfile(join(git_dir, 'commondir'))
  57             )
  58         ):
  59
  60             result = core.isfile(headref) or (
  61                 core.islink(headref) and core.readlink(headref).startswith('refs/')
  62             )
  63         else:
  64             result = is_git_file(git_dir)
  65
  66     return result
  67
  68
  69 def is_git_file(f):
  70     return core.isfile(f) and os.path.basename(f) == '.git'
  71
  72
  73 def is_git_worktree(d):
  74     return is_git_dir(join(d, '.git'))
  75
  76
  77 def is_git_repository(path):
  78     return is_git_worktree(path) or is_git_dir(path)
  79
  80
  81 def read_git_file(path):
  82     """Read the path from a .git-file
  83
  84     `None` is returned when <path> is not a .git-file.
  85
  86     """
  87     result = None
  88     if path and is_git_file(path):
  89         header = 'gitdir: '
  90         data = core.read(path).strip()
  91         if data.startswith(header):
  92             result = data[len(header) :]
  93             if result and not os.path.isabs(result):
  94                 path_folder = os.path.dirname(path)
  95                 repo_relative = join(path_folder, result)
  96                 result = os.path.normpath(repo_relative)
  97     return result
  98
  99
 100 class Paths(object):
 101     """Git repository paths of interest"""
 102
 103     def __init__(self, git_dir=None, git_file=None, worktree=None, common_dir=None):
 104         if git_dir and not is_git_dir(git_dir):
 105             git_dir = None
 106         self.git_dir = git_dir
 107         self.git_file = git_file
 108         self.worktree = worktree
 109         self.common_dir = common_dir
 110
 111     def get(self, path):
 112         ceiling_dirs = set()
 113         ceiling = core.getenv('GIT_CEILING_DIRECTORIES')
 114         if ceiling:
 115             ceiling_dirs.update([x for x in ceiling.split(':') if x])
 116
 117         if path:
 118             path = core.abspath(path)
 119
 120         if not self.git_dir or not self.worktree:
 121             # Search for a .git directory
 122             while path:
 123                 if path in ceiling_dirs:
 124                     break
 125                 if is_git_dir(path):
 126                     if not self.git_dir:
 127                         self.git_dir = path
 128                     basename = os.path.basename(path)
 129                     if not self.worktree and basename == '.git':
 130                         self.worktree = os.path.dirname(path)
 131                 # We are either in a bare repository, or someone set GIT_DIR
 132                 # but did not set GIT_WORK_TREE.
 133                 if self.git_dir:
 134                     if not self.worktree:
 135                         basename = os.path.basename(self.git_dir)
 136                         if basename == '.git':
 137                             self.worktree = os.path.dirname(self.git_dir)
 138                         elif path and not is_git_dir(path):
 139                             self.worktree = path
 140                     break
 141                 gitpath = join(path, '.git')
 142                 if is_git_dir(gitpath):
 143                     if not self.git_dir:
 144                         self.git_dir = gitpath
 145                     if not self.worktree:
 146                         self.worktree = path
 147                     break
 148                 path, dummy = os.path.split(path)
 149                 if not dummy:
 150                     break
 151
 152         if self.git_dir:
 153             git_dir_path = read_git_file(self.git_dir)
 154             if git_dir_path:
 155                 self.git_file = self.git_dir
 156                 self.git_dir = git_dir_path
 157
 158                 commondir_file = join(git_dir_path, 'commondir')
 159                 if core.exists(commondir_file):
 160                     common_path = core.read(commondir_file).strip()
 161                     if common_path:
 162                         if os.path.isabs(common_path):
 163                             common_dir = common_path
 164                         else:
 165                             common_dir = join(git_dir_path, common_path)
 166                             common_dir = os.path.normpath(common_dir)
 167                         self.common_dir = common_dir
 168         # usage: Paths().get()
 169         return self
 170
 171
 172 def find_git_directory(path):
 173     """Perform Git repository discovery
 174
 175     """
 176     return Paths(
 177         git_dir=core.getenv('GIT_DIR'), worktree=core.getenv('GIT_WORK_TREE')
 178     ).get(path)
 179
 180
 181 class Git(object):
 182     """
 183     The Git class manages communication with the Git binary
 184     """
 185
 186     def __init__(self):
 187         self.paths = Paths()
 188
 189         self._valid = {}  #: Store the result of is_git_dir() for performance
 190         self.set_worktree(core.getcwd())
 191
 192     # pylint: disable=no-self-use
 193     def is_git_repository(self, path):
 194         return is_git_repository(path)
 195
 196     def getcwd(self):
 197         """Return the working directory used by git()"""
 198         return self.paths.worktree or self.paths.git_dir
 199
 200     def set_worktree(self, path):
 201         path = core.decode(path)
 202         self.paths = find_git_directory(path)
 203         return self.paths.worktree
 204
 205     def worktree(self):
 206         if not self.paths.worktree:
 207             path = core.abspath(core.getcwd())
 208             self.paths = find_git_directory(path)
 209         return self.paths.worktree
 210
 211     def is_valid(self):
 212         """Is this a valid git repository?
 213
 214         Cache the result to avoid hitting the filesystem.
 215
 216         """
 217         git_dir = self.paths.git_dir
 218         try:
 219             valid = bool(git_dir) and self._valid[git_dir]
 220         except KeyError:
 221             valid = self._valid[git_dir] = is_git_dir(git_dir)
 222
 223         return valid
 224
 225     def git_path(self, *paths):
 226         result = None
 227         if self.paths.git_dir:
 228             result = join(self.paths.git_dir, *paths)
 229         if result and self.paths.common_dir and not core.exists(result):
 230             common_result = join(self.paths.common_dir, *paths)
 231             if core.exists(common_result):
 232                 result = common_result
 233         return result
 234
 235     def git_dir(self):
 236         if not self.paths.git_dir:
 237             path = core.abspath(core.getcwd())
 238             self.paths = find_git_directory(path)
 239         return self.paths.git_dir
 240
 241     def __getattr__(self, name):
 242         git_cmd = partial(self.git, name)
 243         setattr(self, name, git_cmd)
 244         return git_cmd
 245
 246     @staticmethod
 247     def execute(
 248         command,
 249         _cwd=None,
 250         _decode=True,
 251         _encoding=None,
 252         _raw=False,
 253         _stdin=None,
 254         _stderr=subprocess.PIPE,
 255         _stdout=subprocess.PIPE,
 256         _readonly=False,
 257         _no_win32_startupinfo=False,
 258     ):
 259         """
 260         Execute a command and returns its output
 261
 262         :param command: argument list to execute.
 263         :param _cwd: working directory, defaults to the current directory.
 264         :param _decode: whether to decode output, defaults to True.
 265         :param _encoding: default encoding, defaults to None (utf-8).
 266         :param _raw: do not strip trailing whitespace.
 267         :param _stdin: optional stdin filehandle.
 268         :returns (status, out, err): exit status, stdout, stderr
 269
 270         """
 271         # Allow the user to have the command executed in their working dir.
 272         if not _cwd:
 273             _cwd = core.getcwd()
 274
 275         extra = {}
 276
 277         if hasattr(os, 'setsid'):
 278             # SSH uses the SSH_ASKPASS variable only if the process is really
 279             # detached from the TTY (stdin redirection and setting the
 280             # SSH_ASKPASS environment variable is not enough).  To detach a
 281             # process from the console it should fork and call os.setsid().
 282             extra['preexec_fn'] = os.setsid
 283
 284         # Start the process
 285         # Guard against thread-unsafe .git/index.lock files
 286         if not _readonly:
 287             _index_lock.acquire()
 288         try:
 289             status, out, err = core.run_command(
 290                 command,
 291                 cwd=_cwd,
 292                 encoding=_encoding,
 293                 stdin=_stdin,
 294                 stdout=_stdout,
 295                 stderr=_stderr,
 296                 no_win32_startupinfo=_no_win32_startupinfo,
 297                 **extra
 298             )
 299         finally:
 300             # Let the next thread in
 301             if not _readonly:
 302                 _index_lock.release()
 303
 304         if not _raw and out is not None:
 305             out = core.UStr(out.rstrip('\n'), out.encoding)
 306
 307         cola_trace = GIT_COLA_TRACE
 308         if cola_trace == 'trace':
 309             msg = 'trace: ' + core.list2cmdline(command)
 310             Interaction.log_status(status, msg, '')
 311         elif cola_trace == 'full':
 312             if out or err:
 313                 core.print_stderr(
 314                     "%s -> %d: '%s' '%s'" % (' '.join(command), status, out, err)
 315                 )
 316             else:
 317                 core.print_stderr("%s -> %d" % (' '.join(command), status))
 318         elif cola_trace:
 319             core.print_stderr(' '.join(command))
 320
 321         # Allow access to the command's status code
 322         return (status, out, err)
 323
 324     def git(self, cmd, *args, **kwargs):
 325         # Handle optional arguments prior to calling transform_kwargs
 326         # otherwise they'll end up in args, which is bad.
 327         _kwargs = dict(_cwd=self.getcwd())
 328         execute_kwargs = (
 329             '_cwd',
 330             '_decode',
 331             '_encoding',
 332             '_stdin',
 333             '_stdout',
 334             '_stderr',
 335             '_raw',
 336             '_readonly',
 337             '_no_win32_startupinfo',
 338         )
 339
 340         for kwarg in execute_kwargs:
 341             if kwarg in kwargs:
 342                 _kwargs[kwarg] = kwargs.pop(kwarg)
 343
 344         # Prepare the argument list
 345         git_args = [
 346             GIT,
 347             '-c',
 348             'diff.suppressBlankEmpty=false',
 349             '-c',
 350             'log.showSignature=false',
 351             dashify(cmd),
 352         ]
 353         opt_args = transform_kwargs(**kwargs)
 354         call = git_args + opt_args
 355         call.extend(args)
 356         try:
 357             result = self.execute(call, **_kwargs)
 358         except OSError as e:
 359             if WIN32 and e.errno == errno.ENOENT:
 360                 # see if git exists at all. on win32 it can fail with ENOENT in
 361                 # case of argv overflow. we should be safe from that but use
 362                 # defensive coding for the worst-case scenario. On UNIX
 363                 # we have ENAMETOOLONG but that doesn't exist on Windows.
 364                 if _git_is_installed():
 365                     raise e
 366                 _print_win32_git_hint()
 367             result = (1, '', "error: unable to execute '%s'" % GIT)
 368         return result
 369
 370
 371 def _git_is_installed():
 372     """Return True if git is installed"""
 373     # On win32 Git commands can fail with ENOENT in case of argv overflow. we
 374     # should be safe from that but use defensive coding for the worst-case
 375     # scenario. On UNIX we have ENAMETOOLONG but that doesn't exist on
 376     # Windows.
 377     try:
 378         status, _, _ = Git.execute([GIT, '--version'])
 379         result = status == 0
 380     except OSError:
 381         result = False
 382     return result
 383
 384
 385 def transform_kwargs(**kwargs):
 386     """Transform kwargs into git command line options
 387
 388     Callers can assume the following behavior:
 389
 390     Passing foo=None ignores foo, so that callers can
 391     use default values of None that are ignored unless
 392     set explicitly.
 393
 394     Passing foo=False ignore foo, for the same reason.
 395
 396     Passing foo={string-or-number} results in ['--foo=<value>']
 397     in the resulting arguments.
 398
 399     """
 400     args = []
 401     types_to_stringify = (ustr, float, str) + int_types
 402
 403     for k, v in kwargs.items():
 404         if len(k) == 1:
 405             dashes = '-'
 406             eq = ''
 407         else:
 408             dashes = '--'
 409             eq = '='
 410         # isinstance(False, int) is True, so we have to check bool first
 411         if isinstance(v, bool):
 412             if v:
 413                 args.append('%s%s' % (dashes, dashify(k)))
 414             # else: pass  # False is ignored; flag=False inhibits --flag
 415         elif isinstance(v, types_to_stringify):
 416             args.append('%s%s%s%s' % (dashes, dashify(k), eq, v))
 417
 418     return args
 419
 420
 421 def win32_git_error_hint():
 422     return (
 423         '\n'
 424         'NOTE: If you have Git installed in a custom location, e.g.\n'
 425         'C:\\Tools\\Git, then you can create a file at\n'
 426         '~/.config/git-cola/git-bindir with following text\n'
 427         'and git-cola will add the specified location to your $PATH\n'
 428         'automatically when starting cola:\n'
 429         '\n'
 430         r'C:\Tools\Git\bin'
 431     )
 432
 433
 434 @memoize
 435 def _print_win32_git_hint():
 436     hint = '\n' + win32_git_error_hint() + '\n'
 437     core.print_stderr("error: unable to execute 'git'" + hint)
 438
 439
 440 def create():
 441     """Create Git instances
 442
 443     >>> git = create()
 444     >>> status, out, err = git.version()
 445     >>> 'git' == out[:3].lower()
 446     True
 447
 448     """
 449     return Git()