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         """
  43             Returns the next tag - stage to work on.
  44             Returns None for the last stage.
  45         """
  46         try:
  47             return Tag.objects.filter(ordering__gt=self.ordering)[0]
  48         except IndexError:
  49             return None
  50
  51 models.signals.pre_save.connect(Tag.listener_changed, sender=Tag)
  52
  53
  54 class Change(models.Model):
  55     """
  56         Single document change related to previous change. The "parent"
  57         argument points to the version against which this change has been
  58         recorded. Initial text will have a null parent.
  59
  60         Data contains a pickled diff needed to reproduce the initial document.
  61     """
  62     author = models.ForeignKey(User, null=True, blank=True)
  63     author_desc = models.CharField(max_length=128, null=True, blank=True)
  64     patch = models.TextField(blank=True)
  65     tree = models.ForeignKey('Document')
  66     revision = models.IntegerField(db_index=True)
  67
  68     parent = models.ForeignKey('self',
  69                         null=True, blank=True, default=None,
  70                         related_name="children")
  71
  72     merge_parent = models.ForeignKey('self',
  73                         null=True, blank=True, default=None,
  74                         related_name="merge_children")
  75
  76     description = models.TextField(blank=True, default='')
  77     created_at = models.DateTimeField(editable=False, db_index=True,
  78                         default=datetime.now)
  79     publishable = models.BooleanField(default=False)
  80
  81     tags = models.ManyToManyField(Tag)
  82
  83     class Meta:
  84         ordering = ('created_at',)
  85         unique_together = ['tree', 'revision']
  86
  87     def __unicode__(self):
  88         return u"Id: %r, Tree %r, Parent %r, Patch '''\n%s'''" % (self.id, self.tree_id, self.parent_id, self.patch)
  89
  90     def author_str(self):
  91         if self.author:
  92             return "%s %s <%s>" % (
  93                 self.author.first_name,
  94                 self.author.last_name,
  95                 self.author.email)
  96         else:
  97             return self.author_desc
  98
  99
 100     def save(self, *args, **kwargs):
 101         """
 102             take the next available revision number if none yet
 103         """
 104         if self.revision is None:
 105             self.revision = self.tree.revision() + 1
 106         return super(Change, self).save(*args, **kwargs)
 107
 108     @staticmethod
 109     def make_patch(src, dst):
 110         if isinstance(src, unicode):
 111             src = src.encode('utf-8')
 112         if isinstance(dst, unicode):
 113             dst = dst.encode('utf-8')
 114         return pickle.dumps(mdiff.textdiff(src, dst))
 115
 116     def materialize(self):
 117         # special care for merged nodes
 118         if self.parent is None and self.merge_parent is not None:
 119             return self.apply_to(self.merge_parent.materialize())
 120
 121         changes = Change.objects.exclude(parent=None).filter(
 122                         tree=self.tree,
 123                         revision__lte=self.revision).order_by('revision')
 124         text = u''
 125         for change in changes:
 126             text = change.apply_to(text)
 127         return text
 128
 129     def make_child(self, patch, description, author=None,
 130             author_desc=None, tags=None):
 131         ch = self.children.create(patch=patch,
 132                         tree=self.tree, author=author,
 133                         author_desc=author_desc,
 134                         description=description)
 135         if tags is not None:
 136             ch.tags = tags
 137         return ch
 138
 139     def make_merge_child(self, patch, description, author=None,
 140             author_desc=None, tags=None):
 141         ch = self.merge_children.create(patch=patch,
 142                         tree=self.tree, author=author,
 143                         author_desc=author_desc,
 144                         description=description,
 145                         tags=tags)
 146         if tags is not None:
 147             ch.tags = tags
 148         return ch
 149
 150     def apply_to(self, text):
 151         return mdiff.patch(text, pickle.loads(self.patch.encode('ascii')))
 152
 153     def merge_with(self, other, author=None, author_desc=None,
 154             description=u"Automatic merge."):
 155         assert self.tree_id == other.tree_id  # same tree
 156         if other.parent_id == self.pk:
 157             # immediate child
 158             return other
 159
 160         local = self.materialize()
 161         base = other.merge_parent.materialize()
 162         remote = other.apply_to(base)
 163
 164         merge = simplemerge.Merge3Text(base, local, remote)
 165         result = ''.join(merge.merge_lines())
 166         patch = self.make_patch(local, result)
 167         return self.children.create(
 168                     patch=patch, merge_parent=other, tree=self.tree,
 169                     author=author, author_desc=author_desc,
 170                     description=description)
 171
 172     def revert(self, **kwargs):
 173         """ commit this version of a doc as new head """
 174         self.tree.commit(text=self.materialize(), **kwargs)
 175
 176
 177 class Document(models.Model):
 178     """
 179         File in repository.
 180     """
 181     creator = models.ForeignKey(User, null=True, blank=True, editable=False,
 182                 related_name="created_documents")
 183     head = models.ForeignKey(Change,
 184                     null=True, blank=True, default=None,
 185                     help_text=_("This document's current head."),
 186                     editable=False)
 187
 188     user = models.ForeignKey(User, null=True, blank=True)
 189     stage = models.ForeignKey(Tag, null=True, blank=True)
 190
 191     def __unicode__(self):
 192         return u"{0}, HEAD: {1}".format(self.id, self.head_id)
 193
 194     @models.permalink
 195     def get_absolute_url(self):
 196         return ('dvcs.views.document_data', (), {
 197                         'document_id': self.id,
 198                         'version': self.head_id,
 199         })
 200
 201     def materialize(self, change=None):
 202         if self.head is None:
 203             return u''
 204         if change is None:
 205             change = self.head
 206         elif not isinstance(change, Change):
 207             change = self.change_set.get(pk=change)
 208         return change.materialize()
 209
 210     def commit(self, **kwargs):
 211         if 'parent' not in kwargs:
 212             parent = self.head
 213         else:
 214             parent = kwargs['parent']
 215             if not isinstance(parent, Change):
 216                 parent = Change.objects.get(pk=kwargs['parent'])
 217
 218         if 'patch' not in kwargs:
 219             if 'text' not in kwargs:
 220                 raise ValueError("You must provide either patch or target document.")
 221             patch = Change.make_patch(self.materialize(change=parent), kwargs['text'])
 222         else:
 223             if 'text' in kwargs:
 224                 raise ValueError("You can provide only text or patch - not both")
 225             patch = kwargs['patch']
 226
 227         author = kwargs.get('author', None)
 228         author_desc = kwargs.get('author_desc', None)
 229         tags = kwargs.get('tags', [])
 230         if tags:
 231             # set stage to next tag after the commited one
 232             self.stage = max(tags, key=lambda t: t.ordering).next()
 233
 234         old_head = self.head
 235         if parent != old_head:
 236             change = parent.make_merge_child(patch, author=author,
 237                     author_desc=author_desc,
 238                     description=kwargs.get('description', ''),
 239                     tags=tags)
 240             # not Fast-Forward - perform a merge
 241             self.head = old_head.merge_with(change, author=author,
 242                     author_desc=author_desc)
 243         else:
 244             self.head = parent.make_child(patch, author=author,
 245                     author_desc=author_desc,
 246                     description=kwargs.get('description', ''),
 247                     tags=tags)
 248
 249         self.save()
 250         return self.head
 251
 252     def history(self):
 253         return self.change_set.filter(revision__gt=-1)
 254
 255     def revision(self):
 256         rev = self.change_set.aggregate(
 257                 models.Max('revision'))['revision__max']
 258         return rev if rev is not None else -1
 259
 260     def at_revision(self, rev):
 261         if rev is not None:
 262             return self.change_set.get(revision=rev)
 263         else:
 264             return self.head
 265
 266     def publishable(self):
 267         changes = self.change_set.filter(publishable=True).order_by('-created_at')[:1]
 268         if changes.count():
 269             return changes[0]
 270         else:
 271             return None
 272
 273     @staticmethod
 274     def listener_initial_commit(sender, instance, created, **kwargs):
 275         # run for Document and its subclasses
 276         if not isinstance(instance, Document):
 277             return
 278         if created:
 279             instance.head = Change.objects.create(
 280                     revision=-1,
 281                     author=instance.creator,
 282                     patch=Change.make_patch('', ''),
 283                     tree=instance)
 284             instance.save()
 285
 286 models.signals.post_save.connect(Document.listener_initial_commit)