apps/dvcs/models.py

   1 from datetime import datetime
   2
   3 from django.db import models
   4 from django.contrib.auth.models import User
   5 from django.utils.translation import ugettext_lazy as _
   6 from mercurial import mdiff, simplemerge
   7 import pickle
   8
   9
  10 class Tag(models.Model):
  11     """
  12         a tag (e.g. document stage) which can be applied to a change
  13     """
  14
  15     name = models.CharField(_('name'), max_length=64)
  16     slug = models.SlugField(_('slug'), unique=True, max_length=64,
  17             null=True, blank=True)
  18     ordering = models.IntegerField(_('ordering'))
  19
  20     _object_cache = {}
  21
  22     class Meta:
  23         ordering = ['ordering']
  24
  25     def __unicode__(self):
  26         return self.name
  27
  28     @classmethod
  29     def get(cls, slug):
  30         if slug in cls._object_cache:
  31             return cls._object_cache[slug]
  32         else:
  33             obj = cls.objects.get(slug=slug)
  34             cls._object_cache[slug] = obj
  35             return obj
  36
  37     @staticmethod
  38     def listener_changed(sender, instance, **kwargs):
  39         sender._object_cache = {}
  40
  41 models.signals.pre_save.connect(Tag.listener_changed, sender=Tag)
  42
  43
  44 class Change(models.Model):
  45     """
  46         Single document change related to previous change. The "parent"
  47         argument points to the version against which this change has been
  48         recorded. Initial text will have a null parent.
  49
  50         Data contains a pickled diff needed to reproduce the initial document.
  51     """
  52     author = models.ForeignKey(User, null=True, blank=True)
  53     author_desc = models.CharField(max_length=128, null=True, blank=True)
  54     patch = models.TextField(blank=True)
  55     tree = models.ForeignKey('Document')
  56     revision = models.IntegerField(db_index=True)
  57
  58     parent = models.ForeignKey('self',
  59                         null=True, blank=True, default=None,
  60                         related_name="children")
  61
  62     merge_parent = models.ForeignKey('self',
  63                         null=True, blank=True, default=None,
  64                         related_name="merge_children")
  65
  66     description = models.TextField(blank=True, default='')
  67     created_at = models.DateTimeField(editable=False, db_index=True,
  68                         default=datetime.now)
  69
  70     tags = models.ManyToManyField(Tag)
  71
  72     class Meta:
  73         ordering = ('created_at',)
  74         unique_together = ['tree', 'revision']
  75
  76     def __unicode__(self):
  77         return u"Id: %r, Tree %r, Parent %r, Patch '''\n%s'''" % (self.id, self.tree_id, self.parent_id, self.patch)
  78
  79     def author_str(self):
  80         if self.author:
  81             return "%s %s <%s>" % (
  82                 self.author.first_name,
  83                 self.author.last_name,
  84                 self.author.email)
  85         else:
  86             return self.author_desc
  87
  88
  89     def save(self, *args, **kwargs):
  90         """
  91             take the next available revision number if none yet
  92         """
  93         if self.revision is None:
  94             self.revision = self.tree.revision() + 1
  95         return super(Change, self).save(*args, **kwargs)
  96
  97     @staticmethod
  98     def make_patch(src, dst):
  99         if isinstance(src, unicode):
 100             src = src.encode('utf-8')
 101         if isinstance(dst, unicode):
 102             dst = dst.encode('utf-8')
 103         return pickle.dumps(mdiff.textdiff(src, dst))
 104
 105     def materialize(self):
 106         # special care for merged nodes
 107         if self.parent is None and self.merge_parent is not None:
 108             return self.apply_to(self.merge_parent.materialize())
 109
 110         changes = Change.objects.exclude(parent=None).filter(
 111                         tree=self.tree,
 112                         revision__lte=self.revision).order_by('revision')
 113         text = u''
 114         for change in changes:
 115             text = change.apply_to(text)
 116         return text
 117
 118     def make_child(self, patch, description, author=None,
 119             author_desc=None, tags=None):
 120         ch = self.children.create(patch=patch,
 121                         tree=self.tree, author=author,
 122                         author_desc=author_desc,
 123                         description=description)
 124         if tags is not None:
 125             ch.tags = tags
 126         return ch
 127
 128     def make_merge_child(self, patch, description, author=None,
 129             author_desc=None, tags=None):
 130         ch = self.merge_children.create(patch=patch,
 131                         tree=self.tree, author=author,
 132                         author_desc=author_desc,
 133                         description=description,
 134                         tags=tags)
 135         if tags is not None:
 136             ch.tags = tags
 137         return ch
 138
 139     def apply_to(self, text):
 140         return mdiff.patch(text, pickle.loads(self.patch.encode('ascii')))
 141
 142     def merge_with(self, other, author=None, author_desc=None,
 143             description=u"Automatic merge."):
 144         assert self.tree_id == other.tree_id  # same tree
 145         if other.parent_id == self.pk:
 146             # immediate child
 147             return other
 148
 149         local = self.materialize()
 150         base = other.merge_parent.materialize()
 151         remote = other.apply_to(base)
 152
 153         merge = simplemerge.Merge3Text(base, local, remote)
 154         result = ''.join(merge.merge_lines())
 155         patch = self.make_patch(local, result)
 156         return self.children.create(
 157                     patch=patch, merge_parent=other, tree=self.tree,
 158                     author=author, author_desc=author_desc,
 159                     description=description)
 160
 161     def revert(self, **kwargs):
 162         """ commit this version of a doc as new head """
 163         self.tree.commit(text=self.materialize(), **kwargs)
 164
 165
 166 class Document(models.Model):
 167     """
 168         File in repository.
 169     """
 170     creator = models.ForeignKey(User, null=True, blank=True, editable=False)
 171     head = models.ForeignKey(Change,
 172                     null=True, blank=True, default=None,
 173                     help_text=_("This document's current head."),
 174                     editable=False)
 175
 176     def __unicode__(self):
 177         return u"{0}, HEAD: {1}".format(self.id, self.head_id)
 178
 179     @models.permalink
 180     def get_absolute_url(self):
 181         return ('dvcs.views.document_data', (), {
 182                         'document_id': self.id,
 183                         'version': self.head_id,
 184         })
 185
 186     def materialize(self, change=None):
 187         if self.head is None:
 188             return u''
 189         if change is None:
 190             change = self.head
 191         elif not isinstance(change, Change):
 192             change = self.change_set.get(pk=change)
 193         return change.materialize()
 194
 195     def commit(self, **kwargs):
 196         if 'parent' not in kwargs:
 197             parent = self.head
 198         else:
 199             parent = kwargs['parent']
 200             if not isinstance(parent, Change):
 201                 parent = Change.objects.get(pk=kwargs['parent'])
 202
 203         if 'patch' not in kwargs:
 204             if 'text' not in kwargs:
 205                 raise ValueError("You must provide either patch or target document.")
 206             patch = Change.make_patch(self.materialize(change=parent), kwargs['text'])
 207         else:
 208             if 'text' in kwargs:
 209                 raise ValueError("You can provide only text or patch - not both")
 210             patch = kwargs['patch']
 211
 212         author = kwargs.get('author', None)
 213         author_desc = kwargs.get('author_desc', None)
 214         tags = kwargs.get('tags', [])
 215
 216         old_head = self.head
 217         if parent != old_head:
 218             change = parent.make_merge_child(patch, author=author,
 219                     author_desc=author_desc,
 220                     description=kwargs.get('description', ''),
 221                     tags=tags)
 222             # not Fast-Forward - perform a merge
 223             self.head = old_head.merge_with(change, author=author,
 224                     author_desc=author_desc)
 225         else:
 226             self.head = parent.make_child(patch, author=author,
 227                     author_desc=author_desc,
 228                     description=kwargs.get('description', ''),
 229                     tags=tags)
 230
 231         self.save()
 232         return self.head
 233
 234     def history(self):
 235         return self.change_set.filter(revision__gt=-1)
 236
 237     def revision(self):
 238         rev = self.change_set.aggregate(
 239                 models.Max('revision'))['revision__max']
 240         return rev if rev is not None else -1
 241
 242     def at_revision(self, rev):
 243         if rev:
 244             return self.change_set.get(revision=rev)
 245         else:
 246             return self.head
 247
 248     def last_tagged(self, tag):
 249         changes = tag.change_set.filter(tree=self).order_by('-created_at')[:1]
 250         if changes.count():
 251             return changes[0]
 252         else:
 253             return None
 254
 255     @staticmethod
 256     def listener_initial_commit(sender, instance, created, **kwargs):
 257         # run for Document and its subclasses
 258         if not isinstance(instance, Document):
 259             return
 260         if created:
 261             instance.head = Change.objects.create(
 262                     revision=-1,
 263                     author=instance.creator,
 264                     patch=Change.make_patch('', ''),
 265                     tree=instance)
 266             instance.save()
 267
 268 models.signals.post_save.connect(Document.listener_initial_commit)