chiark - git - mdw - 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, refs_dir):
 126         self.__series_dir = series_dir
 127         self.__name = name
 128         self.__dir = os.path.join(self.__series_dir, self.__name)
 129         self.__refs_dir = refs_dir
 130         self.__top_ref_file = os.path.join(self.__refs_dir, self.__name)
 131
 132     def create(self):
 133         os.mkdir(self.__dir)
 134         create_empty_file(os.path.join(self.__dir, 'bottom'))
 135         create_empty_file(os.path.join(self.__dir, 'top'))
 136
 137     def delete(self):
 138         for f in os.listdir(self.__dir):
 139             os.remove(os.path.join(self.__dir, f))
 140         os.rmdir(self.__dir)
 141         os.remove(self.__top_ref_file)
 142
 143     def get_name(self):
 144         return self.__name
 145
 146     def rename(self, newname):
 147         olddir = self.__dir
 148         old_ref_file = self.__top_ref_file
 149         self.__name = newname
 150         self.__dir = os.path.join(self.__series_dir, self.__name)
 151         self.__top_ref_file = os.path.join(self.__refs_dir, self.__name)
 152
 153         os.rename(olddir, self.__dir)
 154         os.rename(old_ref_file, self.__top_ref_file)
 155
 156     def __update_top_ref(self, ref):
 157         write_string(self.__top_ref_file, ref)
 158
 159     def update_top_ref(self):
 160         top = self.get_top()
 161         if top:
 162             self.__update_top_ref(top)
 163
 164     def __get_field(self, name, multiline = False):
 165         id_file = os.path.join(self.__dir, name)
 166         if os.path.isfile(id_file):
 167             line = read_string(id_file, multiline)
 168             if line == '':
 169                 return None
 170             else:
 171                 return line
 172         else:
 173             return None
 174
 175     def __set_field(self, name, value, multiline = False):
 176         fname = os.path.join(self.__dir, name)
 177         if value and value != '':
 178             write_string(fname, value, multiline)
 179         elif os.path.isfile(fname):
 180             os.remove(fname)
 181
 182     def get_old_bottom(self):
 183         return self.__get_field('bottom.old')
 184
 185     def get_bottom(self):
 186         return self.__get_field('bottom')
 187
 188     def set_bottom(self, value, backup = False):
 189         if backup:
 190             curr = self.__get_field('bottom')
 191             if curr != value:
 192                 self.__set_field('bottom.old', curr)
 193             else:
 194                 self.__set_field('bottom.old', None)
 195         self.__set_field('bottom', value)
 196
 197     def get_old_top(self):
 198         return self.__get_field('top.old')
 199
 200     def get_top(self):
 201         return self.__get_field('top')
 202
 203     def set_top(self, value, backup = False):
 204         if backup:
 205             curr = self.__get_field('top')
 206             if curr != value:
 207                 self.__set_field('top.old', curr)
 208             else:
 209                 self.__set_field('top.old', None)
 210         self.__set_field('top', value)
 211         self.__update_top_ref(value)
 212
 213     def restore_old_boundaries(self):
 214         bottom = self.__get_field('bottom.old')
 215         top = self.__get_field('top.old')
 216
 217         if top and bottom:
 218             self.__set_field('bottom', bottom)
 219             self.__set_field('top', top)
 220             self.__update_top_ref(top)
 221             return True
 222         else:
 223             return False
 224
 225     def get_description(self):
 226         return self.__get_field('description', True)
 227
 228     def set_description(self, line):
 229         self.__set_field('description', line, True)
 230
 231     def get_authname(self):
 232         return self.__get_field('authname')
 233
 234     def set_authname(self, name):
 235         if not name:
 236             if config.has_option('stgit', 'authname'):
 237                 name = config.get('stgit', 'authname')
 238             elif 'GIT_AUTHOR_NAME' in os.environ:
 239                 name = os.environ['GIT_AUTHOR_NAME']
 240         self.__set_field('authname', name)
 241
 242     def get_authemail(self):
 243         return self.__get_field('authemail')
 244
 245     def set_authemail(self, address):
 246         if not address:
 247             if config.has_option('stgit', 'authemail'):
 248                 address = config.get('stgit', 'authemail')
 249             elif 'GIT_AUTHOR_EMAIL' in os.environ:
 250                 address = os.environ['GIT_AUTHOR_EMAIL']
 251         self.__set_field('authemail', address)
 252
 253     def get_authdate(self):
 254         return self.__get_field('authdate')
 255
 256     def set_authdate(self, date):
 257         if not date and 'GIT_AUTHOR_DATE' in os.environ:
 258             date = os.environ['GIT_AUTHOR_DATE']
 259         self.__set_field('authdate', date)
 260
 261     def get_commname(self):
 262         return self.__get_field('commname')
 263
 264     def set_commname(self, name):
 265         if not name:
 266             if config.has_option('stgit', 'commname'):
 267                 name = config.get('stgit', 'commname')
 268             elif 'GIT_COMMITTER_NAME' in os.environ:
 269                 name = os.environ['GIT_COMMITTER_NAME']
 270         self.__set_field('commname', name)
 271
 272     def get_commemail(self):
 273         return self.__get_field('commemail')
 274
 275     def set_commemail(self, address):
 276         if not address:
 277             if config.has_option('stgit', 'commemail'):
 278                 address = config.get('stgit', 'commemail')
 279             elif 'GIT_COMMITTER_EMAIL' in os.environ:
 280                 address = os.environ['GIT_COMMITTER_EMAIL']
 281         self.__set_field('commemail', address)
 282
 283
 284 class Series:
 285     """Class including the operations on series
 286     """
 287     def __init__(self, name = None):
 288         """Takes a series name as the parameter.
 289         """
 290         try:
 291             if name:
 292                 self.__name = name
 293             else:
 294                 self.__name = git.get_head_file()
 295             self.__base_dir = git.get_base_dir()
 296         except git.GitException, ex:
 297             raise StackException, 'GIT tree not initialised: %s' % ex
 298
 299         self.__series_dir = os.path.join(self.__base_dir, 'patches',
 300                                          self.__name)
 301         self.__refs_dir = os.path.join(self.__base_dir, 'refs', 'patches',
 302                                        self.__name)
 303         self.__base_file = os.path.join(self.__base_dir, 'refs', 'bases',
 304                                         self.__name)
 305
 306         self.__applied_file = os.path.join(self.__series_dir, 'applied')
 307         self.__unapplied_file = os.path.join(self.__series_dir, 'unapplied')
 308         self.__current_file = os.path.join(self.__series_dir, 'current')
 309         self.__descr_file = os.path.join(self.__series_dir, 'description')
 310
 311         # where this series keeps its patches
 312         self.__patch_dir = os.path.join(self.__series_dir, 'patches')
 313         if not os.path.isdir(self.__patch_dir):
 314             self.__patch_dir = self.__series_dir
 315
 316         # if no __refs_dir, create and populate it (upgrade old repositories)
 317         if self.is_initialised() and not os.path.isdir(self.__refs_dir):
 318             os.makedirs(self.__refs_dir)
 319             for patch in self.get_applied() + self.get_unapplied():
 320                 self.get_patch(patch).update_top_ref()
 321
 322     def get_branch(self):
 323         """Return the branch name for the Series object
 324         """
 325         return self.__name
 326
 327     def __set_current(self, name):
 328         """Sets the topmost patch
 329         """
 330         if name:
 331             write_string(self.__current_file, name)
 332         else:
 333             create_empty_file(self.__current_file)
 334
 335     def get_patch(self, name):
 336         """Return a Patch object for the given name
 337         """
 338         return Patch(name, self.__patch_dir, self.__refs_dir)
 339
 340     def get_current(self):
 341         """Return a Patch object representing the topmost patch
 342         """
 343         if os.path.isfile(self.__current_file):
 344             name = read_string(self.__current_file)
 345         else:
 346             return None
 347         if name == '':
 348             return None
 349         else:
 350             return name
 351
 352     def get_applied(self):
 353         if not os.path.isfile(self.__applied_file):
 354             raise StackException, 'Branch "%s" not initialised' % self.__name
 355         f = file(self.__applied_file)
 356         names = [line.strip() for line in f.readlines()]
 357         f.close()
 358         return names
 359
 360     def get_unapplied(self):
 361         if not os.path.isfile(self.__unapplied_file):
 362             raise StackException, 'Branch "%s" not initialised' % self.__name
 363         f = file(self.__unapplied_file)
 364         names = [line.strip() for line in f.readlines()]
 365         f.close()
 366         return names
 367
 368     def get_base_file(self):
 369         self.__begin_stack_check()
 370         return self.__base_file
 371
 372     def get_protected(self):
 373         return os.path.isfile(os.path.join(self.__series_dir, 'protected'))
 374
 375     def protect(self):
 376         protect_file = os.path.join(self.__series_dir, 'protected')
 377         if not os.path.isfile(protect_file):
 378             create_empty_file(protect_file)
 379
 380     def unprotect(self):
 381         protect_file = os.path.join(self.__series_dir, 'protected')
 382         if os.path.isfile(protect_file):
 383             os.remove(protect_file)
 384
 385     def get_description(self):
 386         if os.path.isfile(self.__descr_file):
 387             return read_string(self.__descr_file)
 388         else:
 389             return ''
 390
 391     def __patch_is_current(self, patch):
 392         return patch.get_name() == read_string(self.__current_file)
 393
 394     def __patch_applied(self, name):
 395         """Return true if the patch exists in the applied list
 396         """
 397         return name in self.get_applied()
 398
 399     def __patch_unapplied(self, name):
 400         """Return true if the patch exists in the unapplied list
 401         """
 402         return name in self.get_unapplied()
 403
 404     def __begin_stack_check(self):
 405         """Save the current HEAD into .git/refs/heads/base if the stack
 406         is empty
 407         """
 408         if len(self.get_applied()) == 0:
 409             head = git.get_head()
 410             write_string(self.__base_file, head)
 411
 412     def __end_stack_check(self):
 413         """Remove .git/refs/heads/base if the stack is empty.
 414         This warning should never happen
 415         """
 416         if len(self.get_applied()) == 0 \
 417            and read_string(self.__base_file) != git.get_head():
 418             print 'Warning: stack empty but the HEAD and base are different'
 419
 420     def head_top_equal(self):
 421         """Return true if the head and the top are the same
 422         """
 423         crt = self.get_current()
 424         if not crt:
 425             # we don't care, no patches applied
 426             return True
 427         return git.get_head() == Patch(crt, self.__patch_dir,
 428                                        self.__refs_dir).get_top()
 429
 430     def is_initialised(self):
 431         """Checks if series is already initialised
 432         """
 433         return os.path.isdir(self.__patch_dir)
 434
 435     def init(self):
 436         """Initialises the stgit series
 437         """
 438         bases_dir = os.path.join(self.__base_dir, 'refs', 'bases')
 439
 440         if self.is_initialised():
 441             raise StackException, self.__patch_dir + ' already exists'
 442         os.makedirs(self.__patch_dir)
 443
 444         if not os.path.isdir(bases_dir):
 445             os.makedirs(bases_dir)
 446
 447         create_empty_file(self.__applied_file)
 448         create_empty_file(self.__unapplied_file)
 449         create_empty_file(self.__descr_file)
 450         os.makedirs(os.path.join(self.__series_dir, 'patches'))
 451         os.makedirs(self.__refs_dir)
 452         self.__begin_stack_check()
 453
 454     def convert(self):
 455         """Either convert to use a separate patch directory, or
 456         unconvert to place the patches in the same directory with
 457         series control files
 458         """
 459         if self.__patch_dir == self.__series_dir:
 460             print 'Converting old-style to new-style...',
 461             sys.stdout.flush()
 462
 463             self.__patch_dir = os.path.join(self.__series_dir, 'patches')
 464             os.makedirs(self.__patch_dir)
 465
 466             for p in self.get_applied() + self.get_unapplied():
 467                 src = os.path.join(self.__series_dir, p)
 468                 dest = os.path.join(self.__patch_dir, p)
 469                 os.rename(src, dest)
 470
 471             print 'done'
 472
 473         else:
 474             print 'Converting new-style to old-style...',
 475             sys.stdout.flush()
 476
 477             for p in self.get_applied() + self.get_unapplied():
 478                 src = os.path.join(self.__patch_dir, p)
 479                 dest = os.path.join(self.__series_dir, p)
 480                 os.rename(src, dest)
 481
 482             if not os.listdir(self.__patch_dir):
 483                 os.rmdir(self.__patch_dir)
 484                 print 'done'
 485             else:
 486                 print 'Patch directory %s is not empty.' % self.__name
 487
 488             self.__patch_dir = self.__series_dir
 489
 490     def rename(self, to_name):
 491         """Renames a series
 492         """
 493         to_stack = Series(to_name)
 494
 495         if to_stack.is_initialised():
 496             raise StackException, '"%s" already exists' % to_stack.get_branch()
 497         if os.path.exists(to_stack.__base_file):
 498             os.remove(to_stack.__base_file)
 499
 500         git.rename_branch(self.__name, to_name)
 501
 502         if os.path.isdir(self.__series_dir):
 503             os.rename(self.__series_dir, to_stack.__series_dir)
 504         if os.path.exists(self.__base_file):
 505             os.rename(self.__base_file, to_stack.__base_file)
 506
 507         self.__init__(to_name)
 508
 509     def clone(self, target_series):
 510         """Clones a series
 511         """
 512         base = read_string(self.get_base_file())
 513         git.create_branch(target_series, tree_id = base)
 514         Series(target_series).init()
 515         new_series = Series(target_series)
 516
 517         # generate an artificial description file
 518         write_string(new_series.__descr_file, 'clone of "%s"' % self.__name)
 519
 520         # clone self's entire series as unapplied patches
 521         patches = self.get_applied() + self.get_unapplied()
 522         patches.reverse()
 523         for p in patches:
 524             patch = self.get_patch(p)
 525             new_series.new_patch(p, message = patch.get_description(),
 526                                  can_edit = False, unapplied = True,
 527                                  bottom = patch.get_bottom(),
 528                                  top = patch.get_top(),
 529                                  author_name = patch.get_authname(),
 530                                  author_email = patch.get_authemail(),
 531                                  author_date = patch.get_authdate())
 532
 533         # fast forward the cloned series to self's top
 534         new_series.forward_patches(self.get_applied())
 535
 536     def delete(self, force = False):
 537         """Deletes an stgit series
 538         """
 539         if self.is_initialised():
 540             patches = self.get_unapplied() + self.get_applied()
 541             if not force and patches:
 542                 raise StackException, \
 543                       'Cannot delete: the series still contains patches'
 544             for p in patches:
 545                 Patch(p, self.__patch_dir, self.__refs_dir).delete()
 546
 547             if os.path.exists(self.__applied_file):
 548                 os.remove(self.__applied_file)
 549             if os.path.exists(self.__unapplied_file):
 550                 os.remove(self.__unapplied_file)
 551             if os.path.exists(self.__current_file):
 552                 os.remove(self.__current_file)
 553             if os.path.exists(self.__descr_file):
 554                 os.remove(self.__descr_file)
 555             if not os.listdir(self.__patch_dir):
 556                 os.rmdir(self.__patch_dir)
 557             else:
 558                 print 'Patch directory %s is not empty.' % self.__name
 559             if not os.listdir(self.__series_dir):
 560                 os.rmdir(self.__series_dir)
 561             else:
 562                 print 'Series directory %s is not empty.' % self.__name
 563             if not os.listdir(self.__refs_dir):
 564                 os.rmdir(self.__refs_dir)
 565             else:
 566                 print 'Refs directory %s is not empty.' % self.__refs_dir
 567
 568         if os.path.exists(self.__base_file):
 569             os.remove(self.__base_file)
 570
 571     def refresh_patch(self, files = None, message = None, edit = False,
 572                       show_patch = False,
 573                       cache_update = True,
 574                       author_name = None, author_email = None,
 575                       author_date = None,
 576                       committer_name = None, committer_email = None):
 577         """Generates a new commit for the given patch
 578         """
 579         name = self.get_current()
 580         if not name:
 581             raise StackException, 'No patches applied'
 582
 583         patch = Patch(name, self.__patch_dir, self.__refs_dir)
 584
 585         descr = patch.get_description()
 586         if not (message or descr):
 587             edit = True
 588             descr = ''
 589         elif message:
 590             descr = message
 591
 592         if not message and edit:
 593             descr = edit_file(self, descr.rstrip(), \
 594                               'Please edit the description for patch "%s" ' \
 595                               'above.' % name, show_patch)
 596
 597         if not author_name:
 598             author_name = patch.get_authname()
 599         if not author_email:
 600             author_email = patch.get_authemail()
 601         if not author_date:
 602             author_date = patch.get_authdate()
 603         if not committer_name:
 604             committer_name = patch.get_commname()
 605         if not committer_email:
 606             committer_email = patch.get_commemail()
 607
 608         commit_id = git.commit(files = files,
 609                                message = descr, parents = [patch.get_bottom()],
 610                                cache_update = cache_update,
 611                                allowempty = True,
 612                                author_name = author_name,
 613                                author_email = author_email,
 614                                author_date = author_date,
 615                                committer_name = committer_name,
 616                                committer_email = committer_email)
 617
 618         patch.set_top(commit_id)
 619         patch.set_description(descr)
 620         patch.set_authname(author_name)
 621         patch.set_authemail(author_email)
 622         patch.set_authdate(author_date)
 623         patch.set_commname(committer_name)
 624         patch.set_commemail(committer_email)
 625
 626         return commit_id
 627
 628     def new_patch(self, name, message = None, can_edit = True,
 629                   unapplied = False, show_patch = False,
 630                   top = None, bottom = None,
 631                   author_name = None, author_email = None, author_date = None,
 632                   committer_name = None, committer_email = None,
 633                   before_existing = False):
 634         """Creates a new patch
 635         """
 636         if self.__patch_applied(name) or self.__patch_unapplied(name):
 637             raise StackException, 'Patch "%s" already exists' % name
 638
 639         if not message and can_edit:
 640             descr = edit_file(self, None, \
 641                               'Please enter the description for patch "%s" ' \
 642                               'above.' % name, show_patch)
 643         else:
 644             descr = message
 645
 646         head = git.get_head()
 647
 648         self.__begin_stack_check()
 649
 650         patch = Patch(name, self.__patch_dir, self.__refs_dir)
 651         patch.create()
 652
 653         if bottom:
 654             patch.set_bottom(bottom)
 655         else:
 656             patch.set_bottom(head)
 657         if top:
 658             patch.set_top(top)
 659         else:
 660             patch.set_top(head)
 661
 662         patch.set_description(descr)
 663         patch.set_authname(author_name)
 664         patch.set_authemail(author_email)
 665         patch.set_authdate(author_date)
 666         patch.set_commname(committer_name)
 667         patch.set_commemail(committer_email)
 668
 669         if unapplied:
 670             patches = [patch.get_name()] + self.get_unapplied()
 671
 672             f = file(self.__unapplied_file, 'w+')
 673             f.writelines([line + '\n' for line in patches])
 674             f.close()
 675         else:
 676             if before_existing:
 677                 insert_string(self.__applied_file, patch.get_name())
 678                 if not self.get_current():
 679                     self.__set_current(name)
 680             else:
 681                 append_string(self.__applied_file, patch.get_name())
 682                 self.__set_current(name)
 683
 684     def delete_patch(self, name):
 685         """Deletes a patch
 686         """
 687         patch = Patch(name, self.__patch_dir, self.__refs_dir)
 688
 689         if self.__patch_is_current(patch):
 690             self.pop_patch(name)
 691         elif self.__patch_applied(name):
 692             raise StackException, 'Cannot remove an applied patch, "%s", ' \
 693                   'which is not current' % name
 694         elif not name in self.get_unapplied():
 695             raise StackException, 'Unknown patch "%s"' % name
 696
 697         patch.delete()
 698
 699         unapplied = self.get_unapplied()
 700         unapplied.remove(name)
 701         f = file(self.__unapplied_file, 'w+')
 702         f.writelines([line + '\n' for line in unapplied])
 703         f.close()
 704         self.__begin_stack_check()
 705
 706     def forward_patches(self, names):
 707         """Try to fast-forward an array of patches.
 708
 709         On return, patches in names[0:returned_value] have been pushed on the
 710         stack. Apply the rest with push_patch
 711         """
 712         unapplied = self.get_unapplied()
 713         self.__begin_stack_check()
 714
 715         forwarded = 0
 716         top = git.get_head()
 717
 718         for name in names:
 719             assert(name in unapplied)
 720
 721             patch = Patch(name, self.__patch_dir, self.__refs_dir)
 722
 723             head = top
 724             bottom = patch.get_bottom()
 725             top = patch.get_top()
 726
 727             # top != bottom always since we have a commit for each patch
 728             if head == bottom:
 729                 # reset the backup information
 730                 patch.set_bottom(head, backup = True)
 731                 patch.set_top(top, backup = True)
 732
 733             else:
 734                 head_tree = git.get_commit(head).get_tree()
 735                 bottom_tree = git.get_commit(bottom).get_tree()
 736                 if head_tree == bottom_tree:
 737                     # We must just reparent this patch and create a new commit
 738                     # for it
 739                     descr = patch.get_description()
 740                     author_name = patch.get_authname()
 741                     author_email = patch.get_authemail()
 742                     author_date = patch.get_authdate()
 743                     committer_name = patch.get_commname()
 744                     committer_email = patch.get_commemail()
 745
 746                     top_tree = git.get_commit(top).get_tree()
 747
 748                     top = git.commit(message = descr, parents = [head],
 749                                      cache_update = False,
 750                                      tree_id = top_tree,
 751                                      allowempty = True,
 752                                      author_name = author_name,
 753                                      author_email = author_email,
 754                                      author_date = author_date,
 755                                      committer_name = committer_name,
 756                                      committer_email = committer_email)
 757
 758                     patch.set_bottom(head, backup = True)
 759                     patch.set_top(top, backup = True)
 760                 else:
 761                     top = head
 762                     # stop the fast-forwarding, must do a real merge
 763                     break
 764
 765             forwarded+=1
 766             unapplied.remove(name)
 767
 768         if forwarded == 0:
 769             return 0
 770
 771         git.switch(top)
 772
 773         append_strings(self.__applied_file, names[0:forwarded])
 774
 775         f = file(self.__unapplied_file, 'w+')
 776         f.writelines([line + '\n' for line in unapplied])
 777         f.close()
 778
 779         self.__set_current(name)
 780
 781         return forwarded
 782
 783     def push_patch(self, name):
 784         """Pushes a patch on the stack
 785         """
 786         unapplied = self.get_unapplied()
 787         assert(name in unapplied)
 788
 789         self.__begin_stack_check()
 790
 791         patch = Patch(name, self.__patch_dir, self.__refs_dir)
 792
 793         head = git.get_head()
 794         bottom = patch.get_bottom()
 795         top = patch.get_top()
 796
 797         ex = None
 798         modified = False
 799
 800         # top != bottom always since we have a commit for each patch
 801         if head == bottom:
 802             # reset the backup information
 803             patch.set_bottom(bottom, backup = True)
 804             patch.set_top(top, backup = True)
 805
 806             git.switch(top)
 807         else:
 808             # new patch needs to be refreshed.
 809             # The current patch is empty after merge.
 810             patch.set_bottom(head, backup = True)
 811             patch.set_top(head, backup = True)
 812
 813             # Try the fast applying first. If this fails, fall back to the
 814             # three-way merge
 815             if not git.apply_diff(bottom, top):
 816                 # if git.apply_diff() fails, the patch requires a diff3
 817                 # merge and can be reported as modified
 818                 modified = True
 819
 820                 # merge can fail but the patch needs to be pushed
 821                 try:
 822                     git.merge(bottom, head, top)
 823                 except git.GitException, ex:
 824                     print >> sys.stderr, \
 825                           'The merge failed during "push". ' \
 826                           'Use "refresh" after fixing the conflicts'
 827
 828         append_string(self.__applied_file, name)
 829
 830         unapplied.remove(name)
 831         f = file(self.__unapplied_file, 'w+')
 832         f.writelines([line + '\n' for line in unapplied])
 833         f.close()
 834
 835         self.__set_current(name)
 836
 837         # head == bottom case doesn't need to refresh the patch
 838         if head != bottom:
 839             if not ex:
 840                 # if the merge was OK and no conflicts, just refresh the patch
 841                 # The GIT cache was already updated by the merge operation
 842                 self.refresh_patch(cache_update = False)
 843             else:
 844                 raise StackException, str(ex)
 845
 846         return modified
 847
 848     def undo_push(self):
 849         name = self.get_current()
 850         assert(name)
 851
 852         patch = Patch(name, self.__patch_dir, self.__refs_dir)
 853         git.reset()
 854         self.pop_patch(name)
 855         return patch.restore_old_boundaries()
 856
 857     def pop_patch(self, name):
 858         """Pops the top patch from the stack
 859         """
 860         applied = self.get_applied()
 861         applied.reverse()
 862         assert(name in applied)
 863
 864         patch = Patch(name, self.__patch_dir, self.__refs_dir)
 865
 866         git.switch(patch.get_bottom())
 867
 868         # save the new applied list
 869         idx = applied.index(name) + 1
 870
 871         popped = applied[:idx]
 872         popped.reverse()
 873         unapplied = popped + self.get_unapplied()
 874
 875         f = file(self.__unapplied_file, 'w+')
 876         f.writelines([line + '\n' for line in unapplied])
 877         f.close()
 878
 879         del applied[:idx]
 880         applied.reverse()
 881
 882         f = file(self.__applied_file, 'w+')
 883         f.writelines([line + '\n' for line in applied])
 884         f.close()
 885
 886         if applied == []:
 887             self.__set_current(None)
 888         else:
 889             self.__set_current(applied[-1])
 890
 891         self.__end_stack_check()
 892
 893     def empty_patch(self, name):
 894         """Returns True if the patch is empty
 895         """
 896         patch = Patch(name, self.__patch_dir, self.__refs_dir)
 897         bottom = patch.get_bottom()
 898         top = patch.get_top()
 899
 900         if bottom == top:
 901             return True
 902         elif git.get_commit(top).get_tree() \
 903                  == git.get_commit(bottom).get_tree():
 904             return True
 905
 906         return False
 907
 908     def rename_patch(self, oldname, newname):
 909         applied = self.get_applied()
 910         unapplied = self.get_unapplied()
 911
 912         if oldname == newname:
 913             raise StackException, '"To" name and "from" name are the same'
 914
 915         if newname in applied or newname in unapplied:
 916             raise StackException, 'Patch "%s" already exists' % newname
 917
 918         if oldname in unapplied:
 919             Patch(oldname, self.__patch_dir, self.__refs_dir).rename(newname)
 920             unapplied[unapplied.index(oldname)] = newname
 921
 922             f = file(self.__unapplied_file, 'w+')
 923             f.writelines([line + '\n' for line in unapplied])
 924             f.close()
 925         elif oldname in applied:
 926             Patch(oldname, self.__patch_dir, self.__refs_dir).rename(newname)
 927             if oldname == self.get_current():
 928                 self.__set_current(newname)
 929
 930             applied[applied.index(oldname)] = newname
 931
 932             f = file(self.__applied_file, 'w+')
 933             f.writelines([line + '\n' for line in applied])
 934             f.close()
 935         else:
 936             raise StackException, 'Unknown patch "%s"' % oldname