mdw@git.distorted.org.uk Git - stgit/blob - stgit/stack.py

   1 """Basic quilt-like functionality
   2 """
   3
   4 __copyright__ = """
   5 Copyright (C) 2005, Catalin Marinas <catalin.marinas@gmail.com>
   6
   7 This program is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License version 2 as
   9 published by the Free Software Foundation.
  10
  11 This program is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with this program; if not, write to the Free Software
  18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  19 """
  20
  21 import sys, os
  22
  23 from stgit.utils import *
  24 from stgit import git
  25 from stgit.config import config
  26
  27
  28 # stack exception class
  29 class StackException(Exception):
  30     pass
  31
  32 class FilterUntil:
  33     def __init__(self):
  34         self.should_print = True
  35     def __call__(self, x, until_test, prefix):
  36         if until_test(x):
  37             self.should_print = False
  38         if self.should_print:
  39             return x[0:len(prefix)] != prefix
  40         return False
  41
  42 #
  43 # Functions
  44 #
  45 __comment_prefix = 'STG:'
  46 __patch_prefix = 'STG_PATCH:'
  47
  48 def __clean_comments(f):
  49     """Removes lines marked for status in a commit file
  50     """
  51     f.seek(0)
  52
  53     # remove status-prefixed lines
  54     lines = f.readlines()
  55
  56     patch_filter = FilterUntil()
  57     until_test = lambda t: t == (__patch_prefix + '\n')
  58     lines = [l for l in lines if patch_filter(l, until_test, __comment_prefix)]
  59
  60     # remove empty lines at the end
  61     while len(lines) != 0 and lines[-1] == '\n':
  62         del lines[-1]
  63
  64     f.seek(0); f.truncate()
  65     f.writelines(lines)
  66
  67 def edit_file(series, line, comment, show_patch = True):
  68     fname = '.stgit.msg'
  69     tmpl = os.path.join(git.get_base_dir(), 'patchdescr.tmpl')
  70
  71     f = file(fname, 'w+')
  72     if line:
  73         print >> f, line
  74     elif os.path.isfile(tmpl):
  75         print >> f, file(tmpl).read().rstrip()
  76     else:
  77         print >> f
  78     print >> f, __comment_prefix, comment
  79     print >> f, __comment_prefix, \
  80           'Lines prefixed with "%s" will be automatically removed.' \
  81           % __comment_prefix
  82     print >> f, __comment_prefix, \
  83           'Trailing empty lines will be automatically removed.'
  84
  85     if show_patch:
  86        print >> f, __patch_prefix
  87        # series.get_patch(series.get_current()).get_top()
  88        git.diff([], series.get_patch(series.get_current()).get_bottom(), None, f)
  89
  90     #Vim modeline must be near the end.
  91     print >> f, __comment_prefix, 'vi: set textwidth=75 filetype=diff nobackup:'
  92     f.close()
  93
  94     # the editor
  95     if config.has_option('stgit', 'editor'):
  96         editor = config.get('stgit', 'editor')
  97     elif 'EDITOR' in os.environ:
  98         editor = os.environ['EDITOR']
  99     else:
 100         editor = 'vi'
 101     editor += ' %s' % fname
 102
 103     print 'Invoking the editor: "%s"...' % editor,
 104     sys.stdout.flush()
 105     print 'done (exit code: %d)' % os.system(editor)
 106
 107     f = file(fname, 'r+')
 108
 109     __clean_comments(f)
 110     f.seek(0)
 111     result = f.read()
 112
 113     f.close()
 114     os.remove(fname)
 115
 116     return result
 117
 118 #
 119 # Classes
 120 #
 121
 122 class Patch:
 123     """Basic patch implementation
 124     """
 125     def __init__(self, name, series_dir):
 126         self.__series_dir = series_dir
 127         self.__name = name
 128         self.__dir = os.path.join(self.__series_dir, self.__name)
 129
 130     def create(self):
 131         os.mkdir(self.__dir)
 132         create_empty_file(os.path.join(self.__dir, 'bottom'))
 133         create_empty_file(os.path.join(self.__dir, 'top'))
 134
 135     def delete(self):
 136         for f in os.listdir(self.__dir):
 137             os.remove(os.path.join(self.__dir, f))
 138         os.rmdir(self.__dir)
 139
 140     def get_name(self):
 141         return self.__name
 142
 143     def rename(self, newname):
 144         olddir = self.__dir
 145         self.__name = newname
 146         self.__dir = os.path.join(self.__series_dir, self.__name)
 147
 148         os.rename(olddir, self.__dir)
 149
 150     def __get_field(self, name, multiline = False):
 151         id_file = os.path.join(self.__dir, name)
 152         if os.path.isfile(id_file):
 153             line = read_string(id_file, multiline)
 154             if line == '':
 155                 return None
 156             else:
 157                 return line
 158         else:
 159             return None
 160
 161     def __set_field(self, name, value, multiline = False):
 162         fname = os.path.join(self.__dir, name)
 163         if value and value != '':
 164             write_string(fname, value, multiline)
 165         elif os.path.isfile(fname):
 166             os.remove(fname)
 167
 168     def get_old_bottom(self):
 169         return self.__get_field('bottom.old')
 170
 171     def get_bottom(self):
 172         return self.__get_field('bottom')
 173
 174     def set_bottom(self, value, backup = False):
 175         if backup:
 176             curr = self.__get_field('bottom')
 177             if curr != value:
 178                 self.__set_field('bottom.old', curr)
 179             else:
 180                 self.__set_field('bottom.old', None)
 181         self.__set_field('bottom', value)
 182
 183     def get_old_top(self):
 184         return self.__get_field('top.old')
 185
 186     def get_top(self):
 187         return self.__get_field('top')
 188
 189     def set_top(self, value, backup = False):
 190         if backup:
 191             curr = self.__get_field('top')
 192             if curr != value:
 193                 self.__set_field('top.old', curr)
 194             else:
 195                 self.__set_field('top.old', None)
 196         self.__set_field('top', value)
 197
 198     def restore_old_boundaries(self):
 199         bottom = self.__get_field('bottom.old')
 200         top = self.__get_field('top.old')
 201
 202         if top and bottom:
 203             self.__set_field('bottom', bottom)
 204             self.__set_field('top', top)
 205             return True
 206         else:
 207             return False
 208
 209     def get_description(self):
 210         return self.__get_field('description', True)
 211
 212     def set_description(self, line):
 213         self.__set_field('description', line, True)
 214
 215     def get_authname(self):
 216         return self.__get_field('authname')
 217
 218     def set_authname(self, name):
 219         if not name:
 220             if config.has_option('stgit', 'authname'):
 221                 name = config.get('stgit', 'authname')
 222             elif 'GIT_AUTHOR_NAME' in os.environ:
 223                 name = os.environ['GIT_AUTHOR_NAME']
 224         self.__set_field('authname', name)
 225
 226     def get_authemail(self):
 227         return self.__get_field('authemail')
 228
 229     def set_authemail(self, address):
 230         if not address:
 231             if config.has_option('stgit', 'authemail'):
 232                 address = config.get('stgit', 'authemail')
 233             elif 'GIT_AUTHOR_EMAIL' in os.environ:
 234                 address = os.environ['GIT_AUTHOR_EMAIL']
 235         self.__set_field('authemail', address)
 236
 237     def get_authdate(self):
 238         return self.__get_field('authdate')
 239
 240     def set_authdate(self, date):
 241         if not date and 'GIT_AUTHOR_DATE' in os.environ:
 242             date = os.environ['GIT_AUTHOR_DATE']
 243         self.__set_field('authdate', date)
 244
 245     def get_commname(self):
 246         return self.__get_field('commname')
 247
 248     def set_commname(self, name):
 249         if not name:
 250             if config.has_option('stgit', 'commname'):
 251                 name = config.get('stgit', 'commname')
 252             elif 'GIT_COMMITTER_NAME' in os.environ:
 253                 name = os.environ['GIT_COMMITTER_NAME']
 254         self.__set_field('commname', name)
 255
 256     def get_commemail(self):
 257         return self.__get_field('commemail')
 258
 259     def set_commemail(self, address):
 260         if not address:
 261             if config.has_option('stgit', 'commemail'):
 262                 address = config.get('stgit', 'commemail')
 263             elif 'GIT_COMMITTER_EMAIL' in os.environ:
 264                 address = os.environ['GIT_COMMITTER_EMAIL']
 265         self.__set_field('commemail', address)
 266
 267
 268 class Series:
 269     """Class including the operations on series
 270     """
 271     def __init__(self, name = None):
 272         """Takes a series name as the parameter.
 273         """
 274         try:
 275             if name:
 276                 self.__name = name
 277             else:
 278                 self.__name = git.get_head_file()
 279             base_dir = git.get_base_dir()
 280         except git.GitException, ex:
 281             raise StackException, 'GIT tree not initialised: %s' % ex
 282
 283         self.__series_dir = os.path.join(base_dir, 'patches',
 284                                          self.__name)
 285         self.__base_file = os.path.join(base_dir, 'refs', 'bases',
 286                                         self.__name)
 287
 288         self.__applied_file = os.path.join(self.__series_dir, 'applied')
 289         self.__unapplied_file = os.path.join(self.__series_dir, 'unapplied')
 290         self.__current_file = os.path.join(self.__series_dir, 'current')
 291         self.__descr_file = os.path.join(self.__series_dir, 'description')
 292
 293         # where this series keeps its patches
 294         self.__patch_dir = os.path.join(self.__series_dir, 'patches')
 295         if not os.path.isdir(self.__patch_dir):
 296             self.__patch_dir = self.__series_dir
 297
 298     def get_branch(self):
 299         """Return the branch name for the Series object
 300         """
 301         return self.__name
 302
 303     def __set_current(self, name):
 304         """Sets the topmost patch
 305         """
 306         if name:
 307             write_string(self.__current_file, name)
 308         else:
 309             create_empty_file(self.__current_file)
 310
 311     def get_patch(self, name):
 312         """Return a Patch object for the given name
 313         """
 314         return Patch(name, self.__patch_dir)
 315
 316     def get_current(self):
 317         """Return a Patch object representing the topmost patch
 318         """
 319         if os.path.isfile(self.__current_file):
 320             name = read_string(self.__current_file)
 321         else:
 322             return None
 323         if name == '':
 324             return None
 325         else:
 326             return name
 327
 328     def get_applied(self):
 329         if not os.path.isfile(self.__applied_file):
 330             raise StackException, 'Branch "%s" not initialised' % self.__name
 331         f = file(self.__applied_file)
 332         names = [line.strip() for line in f.readlines()]
 333         f.close()
 334         return names
 335
 336     def get_unapplied(self):
 337         if not os.path.isfile(self.__unapplied_file):
 338             raise StackException, 'Branch "%s" not initialised' % self.__name
 339         f = file(self.__unapplied_file)
 340         names = [line.strip() for line in f.readlines()]
 341         f.close()
 342         return names
 343
 344     def get_base_file(self):
 345         return self.__base_file
 346
 347     def get_protected(self):
 348         return os.path.isfile(os.path.join(self.__series_dir, 'protected'))
 349
 350     def protect(self):
 351         protect_file = os.path.join(self.__series_dir, 'protected')
 352         if not os.path.isfile(protect_file):
 353             create_empty_file(protect_file)
 354
 355     def unprotect(self):
 356         protect_file = os.path.join(self.__series_dir, 'protected')
 357         if os.path.isfile(protect_file):
 358             os.remove(protect_file)
 359
 360     def get_description(self):
 361         if os.path.isfile(self.__descr_file):
 362             return read_string(self.__descr_file)
 363         else:
 364             return ''
 365
 366     def __patch_is_current(self, patch):
 367         return patch.get_name() == read_string(self.__current_file)
 368
 369     def __patch_applied(self, name):
 370         """Return true if the patch exists in the applied list
 371         """
 372         return name in self.get_applied()
 373
 374     def __patch_unapplied(self, name):
 375         """Return true if the patch exists in the unapplied list
 376         """
 377         return name in self.get_unapplied()
 378
 379     def __begin_stack_check(self):
 380         """Save the current HEAD into .git/refs/heads/base if the stack
 381         is empty
 382         """
 383         if len(self.get_applied()) == 0:
 384             head = git.get_head()
 385             write_string(self.__base_file, head)
 386
 387     def __end_stack_check(self):
 388         """Remove .git/refs/heads/base if the stack is empty.
 389         This warning should never happen
 390         """
 391         if len(self.get_applied()) == 0 \
 392            and read_string(self.__base_file) != git.get_head():
 393             print 'Warning: stack empty but the HEAD and base are different'
 394
 395     def head_top_equal(self):
 396         """Return true if the head and the top are the same
 397         """
 398         crt = self.get_current()
 399         if not crt:
 400             # we don't care, no patches applied
 401             return True
 402         return git.get_head() == Patch(crt, self.__patch_dir).get_top()
 403
 404     def is_initialised(self):
 405         """Checks if series is already initialised
 406         """
 407         return os.path.isdir(self.__patch_dir)
 408
 409     def init(self):
 410         """Initialises the stgit series
 411         """
 412         bases_dir = os.path.join(git.get_base_dir(), 'refs', 'bases')
 413
 414         if self.is_initialised():
 415             raise StackException, self.__patch_dir + ' already exists'
 416         os.makedirs(self.__patch_dir)
 417
 418         if not os.path.isdir(bases_dir):
 419             os.makedirs(bases_dir)
 420
 421         create_empty_file(self.__applied_file)
 422         create_empty_file(self.__unapplied_file)
 423         create_empty_file(self.__descr_file)
 424         os.makedirs(os.path.join(self.__series_dir, 'patches'))
 425         self.__begin_stack_check()
 426
 427     def convert(self):
 428         """Either convert to use a separate patch directory, or
 429         unconvert to place the patches in the same directory with
 430         series control files
 431         """
 432         if self.__patch_dir == self.__series_dir:
 433             print 'Converting old-style to new-style...',
 434             sys.stdout.flush()
 435
 436             self.__patch_dir = os.path.join(self.__series_dir, 'patches')
 437             os.makedirs(self.__patch_dir)
 438
 439             for p in self.get_applied() + self.get_unapplied():
 440                 src = os.path.join(self.__series_dir, p)
 441                 dest = os.path.join(self.__patch_dir, p)
 442                 os.rename(src, dest)
 443
 444             print 'done'
 445
 446         else:
 447             print 'Converting new-style to old-style...',
 448             sys.stdout.flush()
 449
 450             for p in self.get_applied() + self.get_unapplied():
 451                 src = os.path.join(self.__patch_dir, p)
 452                 dest = os.path.join(self.__series_dir, p)
 453                 os.rename(src, dest)
 454
 455             if not os.listdir(self.__patch_dir):
 456                 os.rmdir(self.__patch_dir)
 457                 print 'done'
 458             else:
 459                 print 'Patch directory %s is not empty.' % self.__name
 460
 461             self.__patch_dir = self.__series_dir
 462
 463     def rename(self, to_name):
 464         """Renames a series
 465         """
 466         to_stack = Series(to_name)
 467
 468         if to_stack.is_initialised():
 469             raise StackException, '"%s" already exists' % to_stack.get_branch()
 470         if os.path.exists(to_stack.__base_file):
 471             os.remove(to_stack.__base_file)
 472
 473         git.rename_branch(self.__name, to_name)
 474
 475         if os.path.isdir(self.__series_dir):
 476             os.rename(self.__series_dir, to_stack.__series_dir)
 477         if os.path.exists(self.__base_file):
 478             os.rename(self.__base_file, to_stack.__base_file)
 479
 480         self.__init__(to_name)
 481
 482     def clone(self, target_series):
 483         """Clones a series
 484         """
 485         base = read_string(self.get_base_file())
 486         git.create_branch(target_series, tree_id = base)
 487         Series(target_series).init()
 488         new_series = Series(target_series)
 489
 490         # generate an artificial description file
 491         write_string(new_series.__descr_file, 'clone of "%s"' % self.__name)
 492
 493         # clone self's entire series as unapplied patches
 494         patches = self.get_applied() + self.get_unapplied()
 495         patches.reverse()
 496         for p in patches:
 497             patch = self.get_patch(p)
 498             new_series.new_patch(p, message = patch.get_description(),
 499                                  can_edit = False, unapplied = True,
 500                                  bottom = patch.get_bottom(),
 501                                  top = patch.get_top(),
 502                                  author_name = patch.get_authname(),
 503                                  author_email = patch.get_authemail(),
 504                                  author_date = patch.get_authdate())
 505
 506         # fast forward the cloned series to self's top
 507         new_series.forward_patches(self.get_applied())
 508
 509     def delete(self, force = False):
 510         """Deletes an stgit series
 511         """
 512         if self.is_initialised():
 513             patches = self.get_unapplied() + self.get_applied()
 514             if not force and patches:
 515                 raise StackException, \
 516                       'Cannot delete: the series still contains patches'
 517             for p in patches:
 518                 Patch(p, self.__patch_dir).delete()
 519
 520             if os.path.exists(self.__applied_file):
 521                 os.remove(self.__applied_file)
 522             if os.path.exists(self.__unapplied_file):
 523                 os.remove(self.__unapplied_file)
 524             if os.path.exists(self.__current_file):
 525                 os.remove(self.__current_file)
 526             if os.path.exists(self.__descr_file):
 527                 os.remove(self.__descr_file)
 528             if not os.listdir(self.__patch_dir):
 529                 os.rmdir(self.__patch_dir)
 530             else:
 531                 print 'Patch directory %s is not empty.' % self.__name
 532             if not os.listdir(self.__series_dir):
 533                 os.rmdir(self.__series_dir)
 534             else:
 535                 print 'Series directory %s is not empty.' % self.__name
 536
 537         if os.path.exists(self.__base_file):
 538             os.remove(self.__base_file)
 539
 540     def refresh_patch(self, files = None, message = None, edit = False,
 541                       show_patch = False,
 542                       cache_update = True,
 543                       author_name = None, author_email = None,
 544                       author_date = None,
 545                       committer_name = None, committer_email = None):
 546         """Generates a new commit for the given patch
 547         """
 548         name = self.get_current()
 549         if not name:
 550             raise StackException, 'No patches applied'
 551
 552         patch = Patch(name, self.__patch_dir)
 553
 554         descr = patch.get_description()
 555         if not (message or descr):
 556             edit = True
 557             descr = ''
 558         elif message:
 559             descr = message
 560
 561         if not message and edit:
 562             descr = edit_file(self, descr.rstrip(), \
 563                               'Please edit the description for patch "%s" ' \
 564                               'above.' % name, show_patch)
 565
 566         if not author_name:
 567             author_name = patch.get_authname()
 568         if not author_email:
 569             author_email = patch.get_authemail()
 570         if not author_date:
 571             author_date = patch.get_authdate()
 572         if not committer_name:
 573             committer_name = patch.get_commname()
 574         if not committer_email:
 575             committer_email = patch.get_commemail()
 576
 577         commit_id = git.commit(files = files,
 578                                message = descr, parents = [patch.get_bottom()],
 579                                cache_update = cache_update,
 580                                allowempty = True,
 581                                author_name = author_name,
 582                                author_email = author_email,
 583                                author_date = author_date,
 584                                committer_name = committer_name,
 585                                committer_email = committer_email)
 586
 587         patch.set_top(commit_id)
 588         patch.set_description(descr)
 589         patch.set_authname(author_name)
 590         patch.set_authemail(author_email)
 591         patch.set_authdate(author_date)
 592         patch.set_commname(committer_name)
 593         patch.set_commemail(committer_email)
 594
 595         return commit_id
 596
 597     def new_patch(self, name, message = None, can_edit = True,
 598                   unapplied = False, show_patch = False,
 599                   top = None, bottom = None,
 600                   author_name = None, author_email = None, author_date = None,
 601                   committer_name = None, committer_email = None):
 602         """Creates a new patch
 603         """
 604         if self.__patch_applied(name) or self.__patch_unapplied(name):
 605             raise StackException, 'Patch "%s" already exists' % name
 606
 607         if not message and can_edit:
 608             descr = edit_file(self, None, \
 609                               'Please enter the description for patch "%s" ' \
 610                               'above.' % name, show_patch)
 611         else:
 612             descr = message
 613
 614         head = git.get_head()
 615
 616         self.__begin_stack_check()
 617
 618         patch = Patch(name, self.__patch_dir)
 619         patch.create()
 620
 621         if bottom:
 622             patch.set_bottom(bottom)
 623         else:
 624             patch.set_bottom(head)
 625         if top:
 626             patch.set_top(top)
 627         else:
 628             patch.set_top(head)
 629
 630         patch.set_description(descr)
 631         patch.set_authname(author_name)
 632         patch.set_authemail(author_email)
 633         patch.set_authdate(author_date)
 634         patch.set_commname(committer_name)
 635         patch.set_commemail(committer_email)
 636
 637         if unapplied:
 638             patches = [patch.get_name()] + self.get_unapplied()
 639
 640             f = file(self.__unapplied_file, 'w+')
 641             f.writelines([line + '\n' for line in patches])
 642             f.close()
 643         else:
 644             append_string(self.__applied_file, patch.get_name())
 645             self.__set_current(name)
 646
 647     def delete_patch(self, name):
 648         """Deletes a patch
 649         """
 650         patch = Patch(name, self.__patch_dir)
 651
 652         if self.__patch_is_current(patch):
 653             self.pop_patch(name)
 654         elif self.__patch_applied(name):
 655             raise StackException, 'Cannot remove an applied patch, "%s", ' \
 656                   'which is not current' % name
 657         elif not name in self.get_unapplied():
 658             raise StackException, 'Unknown patch "%s"' % name
 659
 660         patch.delete()
 661
 662         unapplied = self.get_unapplied()
 663         unapplied.remove(name)
 664         f = file(self.__unapplied_file, 'w+')
 665         f.writelines([line + '\n' for line in unapplied])
 666         f.close()
 667
 668     def forward_patches(self, names):
 669         """Try to fast-forward an array of patches.
 670
 671         On return, patches in names[0:returned_value] have been pushed on the
 672         stack. Apply the rest with push_patch
 673         """
 674         unapplied = self.get_unapplied()
 675         self.__begin_stack_check()
 676
 677         forwarded = 0
 678         top = git.get_head()
 679
 680         for name in names:
 681             assert(name in unapplied)
 682
 683             patch = Patch(name, self.__patch_dir)
 684
 685             head = top
 686             bottom = patch.get_bottom()
 687             top = patch.get_top()
 688
 689             # top != bottom always since we have a commit for each patch
 690             if head == bottom:
 691                 # reset the backup information
 692                 patch.set_bottom(head, backup = True)
 693                 patch.set_top(top, backup = True)
 694
 695             else:
 696                 head_tree = git.get_commit(head).get_tree()
 697                 bottom_tree = git.get_commit(bottom).get_tree()
 698                 if head_tree == bottom_tree:
 699                     # We must just reparent this patch and create a new commit
 700                     # for it
 701                     descr = patch.get_description()
 702                     author_name = patch.get_authname()
 703                     author_email = patch.get_authemail()
 704                     author_date = patch.get_authdate()
 705                     committer_name = patch.get_commname()
 706                     committer_email = patch.get_commemail()
 707
 708                     top_tree = git.get_commit(top).get_tree()
 709
 710                     top = git.commit(message = descr, parents = [head],
 711                                      cache_update = False,
 712                                      tree_id = top_tree,
 713                                      allowempty = True,
 714                                      author_name = author_name,
 715                                      author_email = author_email,
 716                                      author_date = author_date,
 717                                      committer_name = committer_name,
 718                                      committer_email = committer_email)
 719
 720                     patch.set_bottom(head, backup = True)
 721                     patch.set_top(top, backup = True)
 722                 else:
 723                     top = head
 724                     # stop the fast-forwarding, must do a real merge
 725                     break
 726
 727             forwarded+=1
 728             unapplied.remove(name)
 729
 730         if forwarded == 0:
 731             return 0
 732
 733         git.switch(top)
 734
 735         append_strings(self.__applied_file, names[0:forwarded])
 736
 737         f = file(self.__unapplied_file, 'w+')
 738         f.writelines([line + '\n' for line in unapplied])
 739         f.close()
 740
 741         self.__set_current(name)
 742
 743         return forwarded
 744
 745     def push_patch(self, name):
 746         """Pushes a patch on the stack
 747         """
 748         unapplied = self.get_unapplied()
 749         assert(name in unapplied)
 750
 751         self.__begin_stack_check()
 752
 753         patch = Patch(name, self.__patch_dir)
 754
 755         head = git.get_head()
 756         bottom = patch.get_bottom()
 757         top = patch.get_top()
 758
 759         ex = None
 760         modified = False
 761
 762         # top != bottom always since we have a commit for each patch
 763         if head == bottom:
 764             # reset the backup information
 765             patch.set_bottom(bottom, backup = True)
 766             patch.set_top(top, backup = True)
 767
 768             git.switch(top)
 769         else:
 770             # new patch needs to be refreshed.
 771             # The current patch is empty after merge.
 772             patch.set_bottom(head, backup = True)
 773             patch.set_top(head, backup = True)
 774
 775             # Try the fast applying first. If this fails, fall back to the
 776             # three-way merge
 777             if not git.apply_diff(bottom, top):
 778                 # if git.apply_diff() fails, the patch requires a diff3
 779                 # merge and can be reported as modified
 780                 modified = True
 781
 782                 # merge can fail but the patch needs to be pushed
 783                 try:
 784                     git.merge(bottom, head, top)
 785                 except git.GitException, ex:
 786                     print >> sys.stderr, \
 787                           'The merge failed during "push". ' \
 788                           'Use "refresh" after fixing the conflicts'
 789
 790         append_string(self.__applied_file, name)
 791
 792         unapplied.remove(name)
 793         f = file(self.__unapplied_file, 'w+')
 794         f.writelines([line + '\n' for line in unapplied])
 795         f.close()
 796
 797         self.__set_current(name)
 798
 799         # head == bottom case doesn't need to refresh the patch
 800         if head != bottom:
 801             if not ex:
 802                 # if the merge was OK and no conflicts, just refresh the patch
 803                 # The GIT cache was already updated by the merge operation
 804                 self.refresh_patch(cache_update = False)
 805             else:
 806                 raise StackException, str(ex)
 807
 808         return modified
 809
 810     def undo_push(self):
 811         name = self.get_current()
 812         assert(name)
 813
 814         patch = Patch(name, self.__patch_dir)
 815         git.reset()
 816         self.pop_patch(name)
 817         return patch.restore_old_boundaries()
 818
 819     def pop_patch(self, name):
 820         """Pops the top patch from the stack
 821         """
 822         applied = self.get_applied()
 823         applied.reverse()
 824         assert(name in applied)
 825
 826         patch = Patch(name, self.__patch_dir)
 827
 828         git.switch(patch.get_bottom())
 829
 830         # save the new applied list
 831         idx = applied.index(name) + 1
 832
 833         popped = applied[:idx]
 834         popped.reverse()
 835         unapplied = popped + self.get_unapplied()
 836
 837         f = file(self.__unapplied_file, 'w+')
 838         f.writelines([line + '\n' for line in unapplied])
 839         f.close()
 840
 841         del applied[:idx]
 842         applied.reverse()
 843
 844         f = file(self.__applied_file, 'w+')
 845         f.writelines([line + '\n' for line in applied])
 846         f.close()
 847
 848         if applied == []:
 849             self.__set_current(None)
 850         else:
 851             self.__set_current(applied[-1])
 852
 853         self.__end_stack_check()
 854
 855     def empty_patch(self, name):
 856         """Returns True if the patch is empty
 857         """
 858         patch = Patch(name, self.__patch_dir)
 859         bottom = patch.get_bottom()
 860         top = patch.get_top()
 861
 862         if bottom == top:
 863             return True
 864         elif git.get_commit(top).get_tree() \
 865                  == git.get_commit(bottom).get_tree():
 866             return True
 867
 868         return False
 869
 870     def rename_patch(self, oldname, newname):
 871         applied = self.get_applied()
 872         unapplied = self.get_unapplied()
 873
 874         if oldname == newname:
 875             raise StackException, '"To" name and "from" name are the same'
 876
 877         if newname in applied or newname in unapplied:
 878             raise StackException, 'Patch "%s" already exists' % newname
 879
 880         if oldname in unapplied:
 881             Patch(oldname, self.__patch_dir).rename(newname)
 882             unapplied[unapplied.index(oldname)] = newname
 883
 884             f = file(self.__unapplied_file, 'w+')
 885             f.writelines([line + '\n' for line in unapplied])
 886             f.close()
 887         elif oldname in applied:
 888             Patch(oldname, self.__patch_dir).rename(newname)
 889             if oldname == self.get_current():
 890                 self.__set_current(newname)
 891
 892             applied[applied.index(oldname)] = newname
 893
 894             f = file(self.__applied_file, 'w+')
 895             f.writelines([line + '\n' for line in applied])
 896             f.close()
 897         else:
 898             raise StackException, 'Unknown patch "%s"' % oldname