apps/dvcs/models.py

   1 from datetime import datetime
   2
   3 from django.db import models
   4 from django.db.models.base import ModelBase
   5 from django.contrib.auth.models import User
   6 from django.utils.translation import ugettext_lazy as _
   7 from mercurial import mdiff, simplemerge
   8 import pickle
   9
  10
  11 class Tag(models.Model):
  12     """
  13         a tag (e.g. document stage) which can be applied to a change
  14     """
  15
  16     name = models.CharField(_('name'), max_length=64)
  17     slug = models.SlugField(_('slug'), unique=True, max_length=64,
  18             null=True, blank=True)
  19     ordering = models.IntegerField(_('ordering'))
  20
  21     _object_cache = {}
  22
  23     class Meta:
  24         abstract = True
  25         ordering = ['ordering']
  26
  27     def __unicode__(self):
  28         return self.name
  29
  30     @classmethod
  31     def get(cls, slug):
  32         if slug in cls._object_cache:
  33             return cls._object_cache[slug]
  34         else:
  35             obj = cls.objects.get(slug=slug)
  36             cls._object_cache[slug] = obj
  37             return obj
  38
  39     @staticmethod
  40     def listener_changed(sender, instance, **kwargs):
  41         sender._object_cache = {}
  42
  43     def next(self):
  44         """
  45             Returns the next tag - stage to work on.
  46             Returns None for the last stage.
  47         """
  48         try:
  49             return Tag.objects.filter(ordering__gt=self.ordering)[0]
  50         except IndexError:
  51             return None
  52
  53 models.signals.pre_save.connect(Tag.listener_changed, sender=Tag)
  54
  55
  56 class Change(models.Model):
  57     """
  58         Single document change related to previous change. The "parent"
  59         argument points to the version against which this change has been
  60         recorded. Initial text will have a null parent.
  61
  62         Data contains a pickled diff needed to reproduce the initial document.
  63     """
  64     author = models.ForeignKey(User, null=True, blank=True)
  65     author_name = models.CharField(max_length=128, null=True, blank=True)
  66     author_email = models.CharField(max_length=128, null=True, blank=True)
  67     patch = models.TextField(blank=True)
  68     revision = models.IntegerField(db_index=True)
  69
  70     parent = models.ForeignKey('self',
  71                         null=True, blank=True, default=None,
  72                         related_name="children")
  73
  74     merge_parent = models.ForeignKey('self',
  75                         null=True, blank=True, default=None,
  76                         related_name="merge_children")
  77
  78     description = models.TextField(blank=True, default='')
  79     created_at = models.DateTimeField(editable=False, db_index=True,
  80                         default=datetime.now)
  81     publishable = models.BooleanField(default=False)
  82
  83     class Meta:
  84         abstract = True
  85         ordering = ('created_at',)
  86         unique_together = ['tree', 'revision']
  87
  88     def __unicode__(self):
  89         return u"Id: %r, Tree %r, Parent %r, Patch '''\n%s'''" % (self.id, self.tree_id, self.parent_id, self.patch)
  90
  91     def author_str(self):
  92         if self.author:
  93             return "%s %s <%s>" % (
  94                 self.author.first_name,
  95                 self.author.last_name,
  96                 self.author.email)
  97         else:
  98             return "%s <%s>" % (
  99                 self.author_name,
 100                 self.author_email
 101                 )
 102
 103
 104     def save(self, *args, **kwargs):
 105         """
 106             take the next available revision number if none yet
 107         """
 108         if self.revision is None:
 109             self.revision = self.tree.revision() + 1
 110         return super(Change, self).save(*args, **kwargs)
 111
 112     @staticmethod
 113     def make_patch(src, dst):
 114         if isinstance(src, unicode):
 115             src = src.encode('utf-8')
 116         if isinstance(dst, unicode):
 117             dst = dst.encode('utf-8')
 118         return pickle.dumps(mdiff.textdiff(src, dst))
 119
 120     def materialize(self):
 121         # special care for merged nodes
 122         if self.parent is None and self.merge_parent is not None:
 123             return self.apply_to(self.merge_parent.materialize())
 124
 125         changes = self.tree.change_set.exclude(parent=None).filter(
 126                         revision__lte=self.revision).order_by('revision')
 127         text = u''
 128         for change in changes:
 129             text = change.apply_to(text)
 130         return text
 131
 132     def make_child(self, patch, description, author=None,
 133             author_name=None, author_email=None, tags=None):
 134         ch = self.children.create(patch=patch,
 135                         tree=self.tree, author=author,
 136                         author_name=author_name,
 137                         author_email=author_email,
 138                         description=description)
 139         if tags is not None:
 140             ch.tags = tags
 141         return ch
 142
 143     def make_merge_child(self, patch, description, author=None,
 144             author_name=None, author_email=None, tags=None):
 145         ch = self.merge_children.create(patch=patch,
 146                         tree=self.tree, author=author,
 147                         author_name=author_name,
 148                         author_email=author_email,
 149                         description=description,
 150                         tags=tags)
 151         if tags is not None:
 152             ch.tags = tags
 153         return ch
 154
 155     def apply_to(self, text):
 156         return mdiff.patch(text, pickle.loads(self.patch.encode('ascii')))
 157
 158     def merge_with(self, other, author=None,
 159             author_name=None, author_email=None,
 160             description=u"Automatic merge."):
 161         assert self.tree_id == other.tree_id  # same tree
 162         if other.parent_id == self.pk:
 163             # immediate child
 164             return other
 165
 166         local = self.materialize()
 167         base = other.merge_parent.materialize()
 168         remote = other.apply_to(base)
 169
 170         merge = simplemerge.Merge3Text(base, local, remote)
 171         result = ''.join(merge.merge_lines())
 172         patch = self.make_patch(local, result)
 173         return self.children.create(
 174                     patch=patch, merge_parent=other, tree=self.tree,
 175                     author=author,
 176                     author_name=author_name,
 177                     author_email=author_email,
 178                     description=description)
 179
 180     def revert(self, **kwargs):
 181         """ commit this version of a doc as new head """
 182         self.tree.commit(text=self.materialize(), **kwargs)
 183
 184
 185 def create_tag_model(model):
 186     name = model.__name__ + 'Tag'
 187     attrs = {
 188         '__module__': model.__module__,
 189     }
 190     return type(name, (Tag,), attrs)
 191
 192
 193 def create_change_model(model):
 194     name = model.__name__ + 'Change'
 195
 196     attrs = {
 197         '__module__': model.__module__,
 198         'tree': models.ForeignKey(model, related_name='change_set'),
 199         'tags': models.ManyToManyField(model.tag_model, related_name='change_set'),
 200     }
 201     return type(name, (Change,), attrs)
 202
 203
 204
 205 class DocumentMeta(ModelBase):
 206     "Metaclass for Document models."
 207     def __new__(cls, name, bases, attrs):
 208         model = super(DocumentMeta, cls).__new__(cls, name, bases, attrs)
 209         if not model._meta.abstract:
 210             # create a real Tag object and `stage' fk
 211             model.tag_model = create_tag_model(model)
 212             models.ForeignKey(model.tag_model,
 213                 null=True, blank=True).contribute_to_class(model, 'stage')
 214
 215             # create real Change model and `head' fk
 216             model.change_model = create_change_model(model)
 217             models.ForeignKey(model.change_model,
 218                     null=True, blank=True, default=None,
 219                     help_text=_("This document's current head."),
 220                     editable=False).contribute_to_class(model, 'head')
 221
 222         return model
 223
 224
 225
 226 class Document(models.Model):
 227     """
 228         File in repository.
 229     """
 230     __metaclass__ = DocumentMeta
 231
 232     creator = models.ForeignKey(User, null=True, blank=True, editable=False,
 233                 related_name="created_documents")
 234
 235     user = models.ForeignKey(User, null=True, blank=True)
 236
 237     class Meta:
 238         abstract = True
 239
 240     def __unicode__(self):
 241         return u"{0}, HEAD: {1}".format(self.id, self.head_id)
 242
 243     @models.permalink
 244     def get_absolute_url(self):
 245         return ('dvcs.views.document_data', (), {
 246                         'document_id': self.id,
 247                         'version': self.head_id,
 248         })
 249
 250     def materialize(self, change=None):
 251         if self.head is None:
 252             return u''
 253         if change is None:
 254             change = self.head
 255         elif not isinstance(change, Change):
 256             change = self.change_set.get(pk=change)
 257         return change.materialize()
 258
 259     def commit(self, **kwargs):
 260         if 'parent' not in kwargs:
 261             parent = self.head
 262         else:
 263             parent = kwargs['parent']
 264             if not isinstance(parent, Change):
 265                 parent = self.change_set.objects.get(pk=kwargs['parent'])
 266
 267         if 'patch' not in kwargs:
 268             if 'text' not in kwargs:
 269                 raise ValueError("You must provide either patch or target document.")
 270             patch = Change.make_patch(self.materialize(change=parent), kwargs['text'])
 271         else:
 272             if 'text' in kwargs:
 273                 raise ValueError("You can provide only text or patch - not both")
 274             patch = kwargs['patch']
 275
 276         author = kwargs.get('author', None)
 277         author_name = kwargs.get('author_name', None)
 278         author_email = kwargs.get('author_email', None)
 279         tags = kwargs.get('tags', [])
 280         if tags:
 281             # set stage to next tag after the commited one
 282             self.stage = max(tags, key=lambda t: t.ordering).next()
 283
 284         old_head = self.head
 285         if parent != old_head:
 286             change = parent.make_merge_child(patch, author=author,
 287                     author_name=author_name,
 288                     author_email=author_email,
 289                     description=kwargs.get('description', ''),
 290                     tags=tags)
 291             # not Fast-Forward - perform a merge
 292             self.head = old_head.merge_with(change, author=author,
 293                     author_name=author_name,
 294                     author_email=author_email)
 295         else:
 296             self.head = parent.make_child(patch, author=author,
 297                     author_name=author_name,
 298                     author_email=author_email,
 299                     description=kwargs.get('description', ''),
 300                     tags=tags)
 301
 302         self.save()
 303         return self.head
 304
 305     def history(self):
 306         return self.change_set.filter(revision__gt=-1)
 307
 308     def revision(self):
 309         rev = self.change_set.aggregate(
 310                 models.Max('revision'))['revision__max']
 311         return rev if rev is not None else -1
 312
 313     def at_revision(self, rev):
 314         if rev is not None:
 315             return self.change_set.get(revision=rev)
 316         else:
 317             return self.head
 318
 319     def publishable(self):
 320         changes = self.change_set.filter(publishable=True).order_by('-created_at')[:1]
 321         if changes.count():
 322             return changes[0]
 323         else:
 324             return None
 325
 326     @staticmethod
 327     def listener_initial_commit(sender, instance, created, **kwargs):
 328         # run for Document and its subclasses
 329         if not isinstance(instance, Document):
 330             return
 331         if created:
 332             instance.head = instance.change_model.objects.create(
 333                     revision=-1,
 334                     author=instance.creator,
 335                     patch=Change.make_patch('', ''),
 336                     tree=instance)
 337             instance.save()
 338
 339 models.signals.post_save.connect(Document.listener_initial_commit)