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, patch_dir):
 126         self.__patch_dir = patch_dir
 127         self.__name = name
 128         self.__dir = os.path.join(self.__patch_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.__patch_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 and config.has_option('stgit', 'authname'):
 220             name = config.get('stgit', 'authname')
 221         self.__set_field('authname', name)
 222
 223     def get_authemail(self):
 224         return self.__get_field('authemail')
 225
 226     def set_authemail(self, address):
 227         if not address and config.has_option('stgit', 'authemail'):
 228             address = config.get('stgit', 'authemail')
 229         self.__set_field('authemail', address)
 230
 231     def get_authdate(self):
 232         return self.__get_field('authdate')
 233
 234     def set_authdate(self, authdate):
 235         self.__set_field('authdate', authdate)
 236
 237     def get_commname(self):
 238         return self.__get_field('commname')
 239
 240     def set_commname(self, name):
 241         if not name and config.has_option('stgit', 'commname'):
 242             name = config.get('stgit', 'commname')
 243         self.__set_field('commname', name)
 244
 245     def get_commemail(self):
 246         return self.__get_field('commemail')
 247
 248     def set_commemail(self, address):
 249         if not address and config.has_option('stgit', 'commemail'):
 250             address = config.get('stgit', 'commemail')
 251         self.__set_field('commemail', address)
 252
 253
 254 class Series:
 255     """Class including the operations on series
 256     """
 257     def __init__(self, name = None):
 258         """Takes a series name as the parameter.
 259         """
 260         if name:
 261             self.__name = name
 262         else:
 263             self.__name = git.get_head_file()
 264
 265         if self.__name:
 266             base_dir = git.get_base_dir()
 267             self.__patch_dir = os.path.join(base_dir, 'patches',
 268                                             self.__name)
 269             self.__base_file = os.path.join(base_dir, 'refs', 'bases',
 270                                             self.__name)
 271             self.__applied_file = os.path.join(self.__patch_dir, 'applied')
 272             self.__unapplied_file = os.path.join(self.__patch_dir, 'unapplied')
 273             self.__current_file = os.path.join(self.__patch_dir, 'current')
 274             self.__descr_file = os.path.join(self.__patch_dir, 'description')
 275
 276     def get_branch(self):
 277         """Return the branch name for the Series object
 278         """
 279         return self.__name
 280
 281     def __set_current(self, name):
 282         """Sets the topmost patch
 283         """
 284         if name:
 285             write_string(self.__current_file, name)
 286         else:
 287             create_empty_file(self.__current_file)
 288
 289     def get_patch(self, name):
 290         """Return a Patch object for the given name
 291         """
 292         return Patch(name, self.__patch_dir)
 293
 294     def get_current(self):
 295         """Return a Patch object representing the topmost patch
 296         """
 297         if os.path.isfile(self.__current_file):
 298             name = read_string(self.__current_file)
 299         else:
 300             return None
 301         if name == '':
 302             return None
 303         else:
 304             return name
 305
 306     def get_applied(self):
 307         if not os.path.isfile(self.__applied_file):
 308             raise StackException, 'Branch "%s" not initialised' % self.__name
 309         f = file(self.__applied_file)
 310         names = [line.strip() for line in f.readlines()]
 311         f.close()
 312         return names
 313
 314     def get_unapplied(self):
 315         if not os.path.isfile(self.__unapplied_file):
 316             raise StackException, 'Branch "%s" not initialised' % self.__name
 317         f = file(self.__unapplied_file)
 318         names = [line.strip() for line in f.readlines()]
 319         f.close()
 320         return names
 321
 322     def get_base_file(self):
 323         return self.__base_file
 324
 325     def get_protected(self):
 326         return os.path.isfile(os.path.join(self.__patch_dir, 'protected'))
 327
 328     def protect(self):
 329         protect_file = os.path.join(self.__patch_dir, 'protected')
 330         if not os.path.isfile(protect_file):
 331             create_empty_file(protect_file)
 332
 333     def unprotect(self):
 334         protect_file = os.path.join(self.__patch_dir, 'protected')
 335         if os.path.isfile(protect_file):
 336             os.remove(protect_file)
 337
 338     def get_description(self):
 339         if os.path.isfile(self.__descr_file):
 340             return read_string(self.__descr_file)
 341         else:
 342             return ''
 343
 344     def __patch_is_current(self, patch):
 345         return patch.get_name() == read_string(self.__current_file)
 346
 347     def __patch_applied(self, name):
 348         """Return true if the patch exists in the applied list
 349         """
 350         return name in self.get_applied()
 351
 352     def __patch_unapplied(self, name):
 353         """Return true if the patch exists in the unapplied list
 354         """
 355         return name in self.get_unapplied()
 356
 357     def __begin_stack_check(self):
 358         """Save the current HEAD into .git/refs/heads/base if the stack
 359         is empty
 360         """
 361         if len(self.get_applied()) == 0:
 362             head = git.get_head()
 363             write_string(self.__base_file, head)
 364
 365     def __end_stack_check(self):
 366         """Remove .git/refs/heads/base if the stack is empty.
 367         This warning should never happen
 368         """
 369         if len(self.get_applied()) == 0 \
 370            and read_string(self.__base_file) != git.get_head():
 371             print 'Warning: stack empty but the HEAD and base are different'
 372
 373     def head_top_equal(self):
 374         """Return true if the head and the top are the same
 375         """
 376         crt = self.get_current()
 377         if not crt:
 378             # we don't care, no patches applied
 379             return True
 380         return git.get_head() == Patch(crt, self.__patch_dir).get_top()
 381
 382     def is_initialised(self):
 383         """Checks if series is already initialised
 384         """
 385         return os.path.isdir(self.__patch_dir)
 386
 387     def init(self):
 388         """Initialises the stgit series
 389         """
 390         bases_dir = os.path.join(git.get_base_dir(), 'refs', 'bases')
 391
 392         if self.is_initialised():
 393             raise StackException, self.__patch_dir + ' already exists'
 394         os.makedirs(self.__patch_dir)
 395
 396         if not os.path.isdir(bases_dir):
 397             os.makedirs(bases_dir)
 398
 399         create_empty_file(self.__applied_file)
 400         create_empty_file(self.__unapplied_file)
 401         create_empty_file(self.__descr_file)
 402         self.__begin_stack_check()
 403
 404     def rename(self, to_name):
 405         """Renames a series
 406         """
 407         to_stack = Series(to_name)
 408
 409         if to_stack.is_initialised():
 410             raise StackException, '"%s" already exists' % to_stack.get_branch()
 411         if os.path.exists(to_stack.__base_file):
 412             os.remove(to_stack.__base_file)
 413
 414         git.rename_branch(self.__name, to_name)
 415
 416         if os.path.isdir(self.__patch_dir):
 417             os.rename(self.__patch_dir, to_stack.__patch_dir)
 418         if os.path.exists(self.__base_file):
 419             os.rename(self.__base_file, to_stack.__base_file)
 420
 421         self.__init__(to_name)
 422
 423     def clone(self, target_series):
 424         """Clones a series
 425         """
 426         base = read_string(self.get_base_file())
 427         git.create_branch(target_series, tree_id = base)
 428         Series(target_series).init()
 429         new_series = Series(target_series)
 430
 431         # generate an artificial description file
 432         write_string(new_series.__descr_file, 'clone of "%s"' % self.__name)
 433
 434         # clone self's entire series as unapplied patches
 435         patches = self.get_applied() + self.get_unapplied()
 436         patches.reverse()
 437         for p in patches:
 438             patch = self.get_patch(p)
 439             new_series.new_patch(p, message = patch.get_description(),
 440                                  can_edit = False, unapplied = True,
 441                                  bottom = patch.get_bottom(),
 442                                  top = patch.get_top(),
 443                                  author_name = patch.get_authname(),
 444                                  author_email = patch.get_authemail(),
 445                                  author_date = patch.get_authdate())
 446
 447         # fast forward the cloned series to self's top
 448         new_series.forward_patches(self.get_applied())
 449
 450     def delete(self, force = False):
 451         """Deletes an stgit series
 452         """
 453         if self.is_initialised():
 454             patches = self.get_unapplied() + self.get_applied()
 455             if not force and patches:
 456                 raise StackException, \
 457                       'Cannot delete: the series still contains patches'
 458             for p in patches:
 459                 Patch(p, self.__patch_dir).delete()
 460
 461             if os.path.exists(self.__applied_file):
 462                 os.remove(self.__applied_file)
 463             if os.path.exists(self.__unapplied_file):
 464                 os.remove(self.__unapplied_file)
 465             if os.path.exists(self.__current_file):
 466                 os.remove(self.__current_file)
 467             if os.path.exists(self.__descr_file):
 468                 os.remove(self.__descr_file)
 469             if not os.listdir(self.__patch_dir):
 470                 os.rmdir(self.__patch_dir)
 471             else:
 472                 print 'Series directory %s is not empty.' % self.__name
 473
 474         if os.path.exists(self.__base_file):
 475             os.remove(self.__base_file)
 476
 477     def refresh_patch(self, message = None, edit = False, show_patch = False,
 478                       cache_update = True,
 479                       author_name = None, author_email = None,
 480                       author_date = None,
 481                       committer_name = None, committer_email = None):
 482         """Generates a new commit for the given patch
 483         """
 484         name = self.get_current()
 485         if not name:
 486             raise StackException, 'No patches applied'
 487
 488         patch = Patch(name, self.__patch_dir)
 489
 490         descr = patch.get_description()
 491         if not (message or descr):
 492             edit = True
 493             descr = ''
 494         elif message:
 495             descr = message
 496
 497         if not message and edit:
 498             descr = edit_file(self, descr.rstrip(), \
 499                               'Please edit the description for patch "%s" ' \
 500                               'above.' % name, show_patch)
 501
 502         if not author_name:
 503             author_name = patch.get_authname()
 504         if not author_email:
 505             author_email = patch.get_authemail()
 506         if not author_date:
 507             author_date = patch.get_authdate()
 508         if not committer_name:
 509             committer_name = patch.get_commname()
 510         if not committer_email:
 511             committer_email = patch.get_commemail()
 512
 513         commit_id = git.commit(message = descr, parents = [patch.get_bottom()],
 514                                cache_update = cache_update,
 515                                allowempty = True,
 516                                author_name = author_name,
 517                                author_email = author_email,
 518                                author_date = author_date,
 519                                committer_name = committer_name,
 520                                committer_email = committer_email)
 521
 522         patch.set_top(commit_id)
 523         patch.set_description(descr)
 524         patch.set_authname(author_name)
 525         patch.set_authemail(author_email)
 526         patch.set_authdate(author_date)
 527         patch.set_commname(committer_name)
 528         patch.set_commemail(committer_email)
 529
 530         return commit_id
 531
 532     def new_patch(self, name, message = None, can_edit = True,
 533                   unapplied = False, show_patch = False,
 534                   top = None, bottom = None,
 535                   author_name = None, author_email = None, author_date = None,
 536                   committer_name = None, committer_email = None):
 537         """Creates a new patch
 538         """
 539         if self.__patch_applied(name) or self.__patch_unapplied(name):
 540             raise StackException, 'Patch "%s" already exists' % name
 541
 542         if not message and can_edit:
 543             descr = edit_file(self, None, \
 544                               'Please enter the description for patch "%s" ' \
 545                               'above.' % name, show_patch)
 546         else:
 547             descr = message
 548
 549         head = git.get_head()
 550
 551         self.__begin_stack_check()
 552
 553         patch = Patch(name, self.__patch_dir)
 554         patch.create()
 555
 556         if bottom:
 557             patch.set_bottom(bottom)
 558         else:
 559             patch.set_bottom(head)
 560         if top:
 561             patch.set_top(top)
 562         else:
 563             patch.set_top(head)
 564
 565         patch.set_description(descr)
 566         patch.set_authname(author_name)
 567         patch.set_authemail(author_email)
 568         patch.set_authdate(author_date)
 569         patch.set_commname(committer_name)
 570         patch.set_commemail(committer_email)
 571
 572         if unapplied:
 573             patches = [patch.get_name()] + self.get_unapplied()
 574
 575             f = file(self.__unapplied_file, 'w+')
 576             f.writelines([line + '\n' for line in patches])
 577             f.close()
 578         else:
 579             append_string(self.__applied_file, patch.get_name())
 580             self.__set_current(name)
 581
 582     def delete_patch(self, name):
 583         """Deletes a patch
 584         """
 585         patch = Patch(name, self.__patch_dir)
 586
 587         if self.__patch_is_current(patch):
 588             self.pop_patch(name)
 589         elif self.__patch_applied(name):
 590             raise StackException, 'Cannot remove an applied patch, "%s", ' \
 591                   'which is not current' % name
 592         elif not name in self.get_unapplied():
 593             raise StackException, 'Unknown patch "%s"' % name
 594
 595         patch.delete()
 596
 597         unapplied = self.get_unapplied()
 598         unapplied.remove(name)
 599         f = file(self.__unapplied_file, 'w+')
 600         f.writelines([line + '\n' for line in unapplied])
 601         f.close()
 602
 603     def forward_patches(self, names):
 604         """Try to fast-forward an array of patches.
 605
 606         On return, patches in names[0:returned_value] have been pushed on the
 607         stack. Apply the rest with push_patch
 608         """
 609         unapplied = self.get_unapplied()
 610         self.__begin_stack_check()
 611
 612         forwarded = 0
 613         top = git.get_head()
 614
 615         for name in names:
 616             assert(name in unapplied)
 617
 618             patch = Patch(name, self.__patch_dir)
 619
 620             head = top
 621             bottom = patch.get_bottom()
 622             top = patch.get_top()
 623
 624             # top != bottom always since we have a commit for each patch
 625             if head == bottom:
 626                 # reset the backup information
 627                 patch.set_bottom(head, backup = True)
 628                 patch.set_top(top, backup = True)
 629
 630             else:
 631                 head_tree = git.get_commit(head).get_tree()
 632                 bottom_tree = git.get_commit(bottom).get_tree()
 633                 if head_tree == bottom_tree:
 634                     # We must just reparent this patch and create a new commit
 635                     # for it
 636                     descr = patch.get_description()
 637                     author_name = patch.get_authname()
 638                     author_email = patch.get_authemail()
 639                     author_date = patch.get_authdate()
 640                     committer_name = patch.get_commname()
 641                     committer_email = patch.get_commemail()
 642
 643                     top_tree = git.get_commit(top).get_tree()
 644
 645                     top = git.commit(message = descr, parents = [head],
 646                                      cache_update = False,
 647                                      tree_id = top_tree,
 648                                      allowempty = True,
 649                                      author_name = author_name,
 650                                      author_email = author_email,
 651                                      author_date = author_date,
 652                                      committer_name = committer_name,
 653                                      committer_email = committer_email)
 654
 655                     patch.set_bottom(head, backup = True)
 656                     patch.set_top(top, backup = True)
 657                 else:
 658                     top = head
 659                     # stop the fast-forwarding, must do a real merge
 660                     break
 661
 662             forwarded+=1
 663             unapplied.remove(name)
 664
 665         if forwarded == 0:
 666             return 0
 667
 668         git.switch(top)
 669
 670         append_strings(self.__applied_file, names[0:forwarded])
 671
 672         f = file(self.__unapplied_file, 'w+')
 673         f.writelines([line + '\n' for line in unapplied])
 674         f.close()
 675
 676         self.__set_current(name)
 677
 678         return forwarded
 679
 680     def push_patch(self, name):
 681         """Pushes a patch on the stack
 682         """
 683         unapplied = self.get_unapplied()
 684         assert(name in unapplied)
 685
 686         self.__begin_stack_check()
 687
 688         patch = Patch(name, self.__patch_dir)
 689
 690         head = git.get_head()
 691         bottom = patch.get_bottom()
 692         top = patch.get_top()
 693
 694         ex = None
 695         modified = False
 696
 697         # top != bottom always since we have a commit for each patch
 698         if head == bottom:
 699             # reset the backup information
 700             patch.set_bottom(bottom, backup = True)
 701             patch.set_top(top, backup = True)
 702
 703             git.switch(top)
 704         else:
 705             # new patch needs to be refreshed.
 706             # The current patch is empty after merge.
 707             patch.set_bottom(head, backup = True)
 708             patch.set_top(head, backup = True)
 709
 710             # Try the fast applying first. If this fails, fall back to the
 711             # three-way merge
 712             if not git.apply_diff(bottom, top):
 713                 # if git.apply_diff() fails, the patch requires a diff3
 714                 # merge and can be reported as modified
 715                 modified = True
 716
 717                 # merge can fail but the patch needs to be pushed
 718                 try:
 719                     git.merge(bottom, head, top)
 720                 except git.GitException, ex:
 721                     print >> sys.stderr, \
 722                           'The merge failed during "push". ' \
 723                           'Use "refresh" after fixing the conflicts'
 724
 725         append_string(self.__applied_file, name)
 726
 727         unapplied.remove(name)
 728         f = file(self.__unapplied_file, 'w+')
 729         f.writelines([line + '\n' for line in unapplied])
 730         f.close()
 731
 732         self.__set_current(name)
 733
 734         # head == bottom case doesn't need to refresh the patch
 735         if head != bottom:
 736             if not ex:
 737                 # if the merge was OK and no conflicts, just refresh the patch
 738                 # The GIT cache was already updated by the merge operation
 739                 self.refresh_patch(cache_update = False)
 740             else:
 741                 raise StackException, str(ex)
 742
 743         return modified
 744
 745     def undo_push(self):
 746         name = self.get_current()
 747         assert(name)
 748
 749         patch = Patch(name, self.__patch_dir)
 750         git.reset()
 751         self.pop_patch(name)
 752         return patch.restore_old_boundaries()
 753
 754     def pop_patch(self, name):
 755         """Pops the top patch from the stack
 756         """
 757         applied = self.get_applied()
 758         applied.reverse()
 759         assert(name in applied)
 760
 761         patch = Patch(name, self.__patch_dir)
 762
 763         git.switch(patch.get_bottom())
 764
 765         # save the new applied list
 766         idx = applied.index(name) + 1
 767
 768         popped = applied[:idx]
 769         popped.reverse()
 770         unapplied = popped + self.get_unapplied()
 771
 772         f = file(self.__unapplied_file, 'w+')
 773         f.writelines([line + '\n' for line in unapplied])
 774         f.close()
 775
 776         del applied[:idx]
 777         applied.reverse()
 778
 779         f = file(self.__applied_file, 'w+')
 780         f.writelines([line + '\n' for line in applied])
 781         f.close()
 782
 783         if applied == []:
 784             self.__set_current(None)
 785         else:
 786             self.__set_current(applied[-1])
 787
 788         self.__end_stack_check()
 789
 790     def empty_patch(self, name):
 791         """Returns True if the patch is empty
 792         """
 793         patch = Patch(name, self.__patch_dir)
 794         bottom = patch.get_bottom()
 795         top = patch.get_top()
 796
 797         if bottom == top:
 798             return True
 799         elif git.get_commit(top).get_tree() \
 800                  == git.get_commit(bottom).get_tree():
 801             return True
 802
 803         return False
 804
 805     def rename_patch(self, oldname, newname):
 806         applied = self.get_applied()
 807         unapplied = self.get_unapplied()
 808
 809         if oldname == newname:
 810             raise StackException, '"To" name and "from" name are the same'
 811
 812         if newname in applied or newname in unapplied:
 813             raise StackException, 'Patch "%s" already exists' % newname
 814
 815         if oldname in unapplied:
 816             Patch(oldname, self.__patch_dir).rename(newname)
 817             unapplied[unapplied.index(oldname)] = newname
 818
 819             f = file(self.__unapplied_file, 'w+')
 820             f.writelines([line + '\n' for line in unapplied])
 821             f.close()
 822         elif oldname in applied:
 823             Patch(oldname, self.__patch_dir).rename(newname)
 824             if oldname == self.get_current():
 825                 self.__set_current(newname)
 826
 827             applied[applied.index(oldname)] = newname
 828
 829             f = file(self.__applied_file, 'w+')
 830             f.writelines([line + '\n' for line in applied])
 831             f.close()
 832         else:
 833             raise StackException, 'Unknown patch "%s"' % oldname