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