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     def next(self):
  42         Tag.objects.filter(ordering__gt=self.ordering)
  43
  44 models.signals.pre_save.connect(Tag.listener_changed, sender=Tag)
  45
  46
  47 class Change(models.Model):
  48     """
  49         Single document change related to previous change. The "parent"
  50         argument points to the version against which this change has been
  51         recorded. Initial text will have a null parent.
  52
  53         Data contains a pickled diff needed to reproduce the initial document.
  54     """
  55     author = models.ForeignKey(User, null=True, blank=True)
  56     author_desc = models.CharField(max_length=128, null=True, blank=True)
  57     patch = models.TextField(blank=True)
  58     tree = models.ForeignKey('Document')
  59     revision = models.IntegerField(db_index=True)
  60
  61     parent = models.ForeignKey('self',
  62                         null=True, blank=True, default=None,
  63                         related_name="children")
  64
  65     merge_parent = models.ForeignKey('self',
  66                         null=True, blank=True, default=None,
  67                         related_name="merge_children")
  68
  69     description = models.TextField(blank=True, default='')
  70     created_at = models.DateTimeField(editable=False, db_index=True,
  71                         default=datetime.now)
  72     publishable = models.BooleanField(default=False)
  73
  74     tags = models.ManyToManyField(Tag)
  75
  76     class Meta:
  77         ordering = ('created_at',)
  78         unique_together = ['tree', 'revision']
  79
  80     def __unicode__(self):
  81         return u"Id: %r, Tree %r, Parent %r, Patch '''\n%s'''" % (self.id, self.tree_id, self.parent_id, self.patch)
  82
  83     def author_str(self):
  84         if self.author:
  85             return "%s %s <%s>" % (
  86                 self.author.first_name,
  87                 self.author.last_name,
  88                 self.author.email)
  89         else:
  90             return self.author_desc
  91
  92
  93     def save(self, *args, **kwargs):
  94         """
  95             take the next available revision number if none yet
  96         """
  97         if self.revision is None:
  98             self.revision = self.tree.revision() + 1
  99         return super(Change, self).save(*args, **kwargs)
 100
 101     @staticmethod
 102     def make_patch(src, dst):
 103         if isinstance(src, unicode):
 104             src = src.encode('utf-8')
 105         if isinstance(dst, unicode):
 106             dst = dst.encode('utf-8')
 107         return pickle.dumps(mdiff.textdiff(src, dst))
 108
 109     def materialize(self):
 110         # special care for merged nodes
 111         if self.parent is None and self.merge_parent is not None:
 112             return self.apply_to(self.merge_parent.materialize())
 113
 114         changes = Change.objects.exclude(parent=None).filter(
 115                         tree=self.tree,
 116                         revision__lte=self.revision).order_by('revision')
 117         text = u''
 118         for change in changes:
 119             text = change.apply_to(text)
 120         return text
 121
 122     def make_child(self, patch, description, author=None,
 123             author_desc=None, tags=None):
 124         ch = self.children.create(patch=patch,
 125                         tree=self.tree, author=author,
 126                         author_desc=author_desc,
 127                         description=description)
 128         if tags is not None:
 129             ch.tags = tags
 130         return ch
 131
 132     def make_merge_child(self, patch, description, author=None,
 133             author_desc=None, tags=None):
 134         ch = self.merge_children.create(patch=patch,
 135                         tree=self.tree, author=author,
 136                         author_desc=author_desc,
 137                         description=description,
 138                         tags=tags)
 139         if tags is not None:
 140             ch.tags = tags
 141         return ch
 142
 143     def apply_to(self, text):
 144         return mdiff.patch(text, pickle.loads(self.patch.encode('ascii')))
 145
 146     def merge_with(self, other, author=None, author_desc=None,
 147             description=u"Automatic merge."):
 148         assert self.tree_id == other.tree_id  # same tree
 149         if other.parent_id == self.pk:
 150             # immediate child
 151             return other
 152
 153         local = self.materialize()
 154         base = other.merge_parent.materialize()
 155         remote = other.apply_to(base)
 156
 157         merge = simplemerge.Merge3Text(base, local, remote)
 158         result = ''.join(merge.merge_lines())
 159         patch = self.make_patch(local, result)
 160         return self.children.create(
 161                     patch=patch, merge_parent=other, tree=self.tree,
 162                     author=author, author_desc=author_desc,
 163                     description=description)
 164
 165     def revert(self, **kwargs):
 166         """ commit this version of a doc as new head """
 167         self.tree.commit(text=self.materialize(), **kwargs)
 168
 169
 170 class Document(models.Model):
 171     """
 172         File in repository.
 173     """
 174     creator = models.ForeignKey(User, null=True, blank=True, editable=False,
 175                 related_name="created_documents")
 176     head = models.ForeignKey(Change,
 177                     null=True, blank=True, default=None,
 178                     help_text=_("This document's current head."),
 179                     editable=False)
 180
 181     user = models.ForeignKey(User, null=True, blank=True)
 182     stage = models.ForeignKey(Tag, null=True, blank=True)
 183
 184     def __unicode__(self):
 185         return u"{0}, HEAD: {1}".format(self.id, self.head_id)
 186
 187     @models.permalink
 188     def get_absolute_url(self):
 189         return ('dvcs.views.document_data', (), {
 190                         'document_id': self.id,
 191                         'version': self.head_id,
 192         })
 193
 194     def materialize(self, change=None):
 195         if self.head is None:
 196             return u''
 197         if change is None:
 198             change = self.head
 199         elif not isinstance(change, Change):
 200             change = self.change_set.get(pk=change)
 201         return change.materialize()
 202
 203     def commit(self, **kwargs):
 204         if 'parent' not in kwargs:
 205             parent = self.head
 206         else:
 207             parent = kwargs['parent']
 208             if not isinstance(parent, Change):
 209                 parent = Change.objects.get(pk=kwargs['parent'])
 210
 211         if 'patch' not in kwargs:
 212             if 'text' not in kwargs:
 213                 raise ValueError("You must provide either patch or target document.")
 214             patch = Change.make_patch(self.materialize(change=parent), kwargs['text'])
 215         else:
 216             if 'text' in kwargs:
 217                 raise ValueError("You can provide only text or patch - not both")
 218             patch = kwargs['patch']
 219
 220         author = kwargs.get('author', None)
 221         author_desc = kwargs.get('author_desc', None)
 222         tags = kwargs.get('tags', [])
 223
 224         old_head = self.head
 225         if parent != old_head:
 226             change = parent.make_merge_child(patch, author=author,
 227                     author_desc=author_desc,
 228                     description=kwargs.get('description', ''),
 229                     tags=tags)
 230             # not Fast-Forward - perform a merge
 231             self.head = old_head.merge_with(change, author=author,
 232                     author_desc=author_desc)
 233         else:
 234             self.head = parent.make_child(patch, author=author,
 235                     author_desc=author_desc,
 236                     description=kwargs.get('description', ''),
 237                     tags=tags)
 238
 239         self.save()
 240         return self.head
 241
 242     def history(self):
 243         return self.change_set.filter(revision__gt=-1)
 244
 245     def revision(self):
 246         rev = self.change_set.aggregate(
 247                 models.Max('revision'))['revision__max']
 248         return rev if rev is not None else -1
 249
 250     def at_revision(self, rev):
 251         if rev is not None:
 252             return self.change_set.get(revision=rev)
 253         else:
 254             return self.head
 255
 256     def publishable(self):
 257         changes = self.change_set.filter(publishable=True).order_by('-created_at')[:1]
 258         if changes.count():
 259             return changes[0]
 260         else:
 261             return None
 262
 263     @staticmethod
 264     def listener_initial_commit(sender, instance, created, **kwargs):
 265         # run for Document and its subclasses
 266         if not isinstance(instance, Document):
 267             return
 268         if created:
 269             instance.head = Change.objects.create(
 270                     revision=-1,
 271                     author=instance.creator,
 272                     patch=Change.make_patch('', ''),
 273                     tree=instance)
 274             instance.save()
 275
 276 models.signals.post_save.connect(Document.listener_initial_commit)