From db50b75e23a5cd6b29d1315f3a8ed2b7befeb81f Mon Sep 17 00:00:00 2001
From: =?utf8?q?=C5=81ukasz=20Rekucki?= <lrekucki@gmail.com>
Date: Tue, 22 Jun 2010 02:08:18 +0200
Subject: [PATCH 1/1] Added lqc's DVCS application - mercurial on database.
 Distilled from backend-rewrite branch.

---
 apps/dvcs/__init__.py       |   0
 apps/dvcs/admin.py          |   5 ++
 apps/dvcs/models.py         | 151 +++++++++++++++++++++++++++++++++
 apps/dvcs/tests.py          | 164 ++++++++++++++++++++++++++++++++++++
 apps/dvcs/urls.py           |   6 ++
 apps/dvcs/views.py          |  21 +++++
 redakcja/settings/common.py |   2 +
 redakcja/urls.py            |   1 +
 8 files changed, 350 insertions(+)
 create mode 100644 apps/dvcs/__init__.py
 create mode 100644 apps/dvcs/admin.py
 create mode 100644 apps/dvcs/models.py
 create mode 100644 apps/dvcs/tests.py
 create mode 100644 apps/dvcs/urls.py
 create mode 100644 apps/dvcs/views.py

diff --git a/apps/dvcs/__init__.py b/apps/dvcs/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/apps/dvcs/admin.py b/apps/dvcs/admin.py
new file mode 100644
index 00000000..c81d3b7b
--- /dev/null
+++ b/apps/dvcs/admin.py
@@ -0,0 +1,5 @@
+from django.contrib.admin import site
+from dvcs.models import Document, Change
+
+site.register(Document)
+site.register(Change)
diff --git a/apps/dvcs/models.py b/apps/dvcs/models.py
new file mode 100644
index 00000000..47e7c26d
--- /dev/null
+++ b/apps/dvcs/models.py
@@ -0,0 +1,151 @@
+from django.db import models
+from django.contrib.auth.models import User
+from django.utils.translation import ugettext_lazy as _
+from mercurial import mdiff, simplemerge
+import pickle
+
+class Change(models.Model):
+    """
+        Single document change related to previous change. The "parent"
+        argument points to the version against which this change has been 
+        recorded. Initial text will have a null parent.
+        
+        Data contains a pickled diff needed to reproduce the initial document.
+    """
+    author = models.ForeignKey(User)
+    patch = models.TextField(blank=True)
+    tree = models.ForeignKey('Document')
+
+    parent = models.ForeignKey('self',
+                        null=True, blank=True, default=None,
+                        related_name="children")
+
+    merge_parent = models.ForeignKey('self',
+                        null=True, blank=True, default=None,
+                        related_name="merge_children")
+
+    description = models.TextField(blank=True, default='')
+    created_at = models.DateTimeField(auto_now_add=True)
+
+    class Meta:
+        ordering = ('created_at',)
+
+    def __unicode__(self):
+        return u"Id: %r, Tree %r, Parent %r, Patch '''\n%s'''" % (self.id, self.tree_id, self.parent_id, self.patch)
+
+    @staticmethod
+    def make_patch(src, dst):
+        return pickle.dumps(mdiff.textdiff(src, dst))
+
+    def materialize(self):
+        changes = Change.objects.exclude(parent=None).filter(
+                        tree=self.tree,
+                        created_at__lte=self.created_at).order_by('created_at')
+        text = u''
+        for change in changes:
+            text = change.apply_to(text)
+        return text
+
+    def make_child(self, patch, author, description):
+        return self.children.create(patch=patch,
+                        tree=self.tree, author=author,
+                        description=description)
+
+    def make_merge_child(self, patch, author, description):
+        return self.merge_children.create(patch=patch,
+                        tree=self.tree, author=author,
+                        description=description)
+
+    def apply_to(self, text):
+        return mdiff.patch(text, pickle.loads(self.patch.encode('ascii')))
+
+    def merge_with(self, other, author, description=u"Automatic merge."):
+        assert self.tree_id == other.tree_id  # same tree
+        if other.parent_id == self.pk:
+            # immediate child 
+            return other
+
+        local = self.materialize()
+        base = other.merge_parent.materialize()
+        remote = other.apply_to(base)
+
+        merge = simplemerge.Merge3Text(base, local, remote)
+        result = ''.join(merge.merge_lines())
+        patch = self.make_patch(local, result)
+        return self.children.create(
+                    patch=patch, merge_parent=other, tree=self.tree,
+                    author=author, description=description)
+
+
+class Document(models.Model):
+    """
+        File in repository.        
+    """
+    creator = models.ForeignKey(User)
+    head = models.ForeignKey(Change,
+                    null=True, blank=True, default=None,
+                    help_text=_("This document's current head."))
+
+    # Some meta-data
+    name = models.CharField(max_length=200,
+                help_text=_("Name for this file to display."))
+
+    def __unicode__(self):
+        return u"{0}, HEAD: {1}".format(self.name, self.head_id)
+
+    @models.permalink
+    def get_absolute_url(self):
+        return ('dvcs.views.document_data', (), {
+                        'document_id': self.id,
+                        'version': self.head_id,
+        })
+
+    def materialize(self, version=None):
+        if self.head is None:
+            return u''
+        if version is None:
+            version = self.head
+        elif not isinstance(version, Change):
+            version = self.change_set.get(pk=version)
+        return version.materialize()
+
+    def commit(self, **kwargs):
+        if 'parent' not in kwargs:
+            parent = self.head
+        else:
+            parent = kwargs['parent']
+            if not isinstance(parent, Change):
+                parent = Change.objects.get(pk=kwargs['parent'])
+
+        if 'patch' not in kwargs:
+            if 'text' not in kwargs:
+                raise ValueError("You must provide either patch or target document.")
+            patch = Change.make_patch(self.materialize(version=parent), kwargs['text'])
+        else:
+            if 'text' in kwargs:
+                raise ValueError("You can provide only text or patch - not both")
+            patch = kwargs['patch']
+
+        old_head = self.head
+        if parent != old_head:
+            change = parent.make_merge_child(patch, kwargs['author'], kwargs.get('description', ''))
+            # not Fast-Forward - perform a merge
+            self.head = old_head.merge_with(change, author=kwargs['author'])
+        else:
+            self.head = parent.make_child(patch, kwargs['author'], kwargs.get('description', ''))
+        self.save()
+        return self.head
+
+    def history(self):
+        return self.changes.all()
+
+    @staticmethod
+    def listener_initial_commit(sender, instance, created, **kwargs):
+        if created:
+            instance.head = Change.objects.create(
+                    author=instance.creator,
+                    patch=pickle.dumps(mdiff.textdiff('', '')),
+                    tree=instance)
+            instance.save()
+
+models.signals.post_save.connect(Document.listener_initial_commit, sender=Document)
diff --git a/apps/dvcs/tests.py b/apps/dvcs/tests.py
new file mode 100644
index 00000000..0c712957
--- /dev/null
+++ b/apps/dvcs/tests.py
@@ -0,0 +1,164 @@
+from django.test import TestCase
+from dvcs.models import Change, Document
+from django.contrib.auth.models import User
+
+class DocumentModelTests(TestCase):
+
+    def setUp(self):
+        self.user = User.objects.create_user("tester", "tester@localhost.local")
+
+    def assertTextEqual(self, given, expected):
+        return self.assertEqual(given, expected,
+            "Expected '''%s'''\n differs from text: '''%s'''" % (expected, given)
+        )
+
+    def test_empty_file(self):
+        doc = Document.objects.create(name=u"Sample Document", creator=self.user)
+        self.assert_(doc.head is not None)
+        self.assertEqual(doc.materialize(), u"")
+
+    def test_single_commit(self):
+        doc = Document.objects.create(name=u"Sample Document", creator=self.user)
+        doc.commit(text=u"Ala ma kota", description="Commit #1", author=self.user)
+        self.assert_(doc.head is not None)
+        self.assertEqual(doc.change_set.count(), 2)
+        self.assertEqual(doc.materialize(), u"Ala ma kota")
+
+    def test_chained_commits(self):
+        doc = Document.objects.create(name=u"Sample Document", creator=self.user)
+        c1 = doc.commit(description="Commit #1", text=u"""
+            Line #1
+            Line #2 is cool
+        """, author=self.user)
+        c2 = doc.commit(description="Commit #2", text=u"""
+            Line #1
+            Line #2 is hot
+        """, author=self.user)
+        c3 = doc.commit(description="Commit #3", text=u"""
+            Line #1
+            ... is hot
+            Line #3 ate Line #2
+        """, author=self.user)
+        self.assert_(doc.head is not None)
+        self.assertEqual(doc.change_set.count(), 4)
+
+        self.assertEqual(doc.materialize(), u"""
+            Line #1
+            ... is hot
+            Line #3 ate Line #2
+        """)
+        self.assertEqual(doc.materialize(version=c3), u"""
+            Line #1
+            ... is hot
+            Line #3 ate Line #2
+        """)
+        self.assertEqual(doc.materialize(version=c2), u"""
+            Line #1
+            Line #2 is hot
+        """)
+        self.assertEqual(doc.materialize(version=c1), """
+            Line #1
+            Line #2 is cool
+        """)
+
+
+    def test_parallel_commit_noconflict(self):
+        doc = Document.objects.create(name=u"Sample Document", creator=self.user)
+        self.assert_(doc.head is not None)
+        base = doc.head
+        base = doc.commit(description="Commit #1", text=u"""
+            Line #1
+            Line #2
+""", author=self.user)
+
+        c1 = doc.commit(description="Commit #2", text=u"""
+            Line #1 is hot
+            Line #2
+""", parent=base, author=self.user)
+        self.assertTextEqual(c1.materialize(), u"""
+            Line #1 is hot
+            Line #2
+""")
+        c2 = doc.commit(description="Commit #3", text=u"""
+            Line #1
+            Line #2
+            Line #3
+""", parent=base, author=self.user)
+        self.assertEqual(doc.change_set.count(), 5)
+        self.assertTextEqual(doc.materialize(), u"""
+            Line #1 is hot
+            Line #2
+            Line #3
+""")
+
+    def test_parallel_commit_conflict(self):
+        doc = Document.objects.create(name=u"Sample Document", creator=self.user)
+        self.assert_(doc.head is not None)
+        base = doc.head
+        base = doc.commit(description="Commit #1", text=u"""
+Line #1
+Line #2
+Line #3
+""", author=self.user)
+
+        c1 = doc.commit(description="Commit #2", text=u"""
+Line #1
+Line #2 is hot
+Line #3
+""", parent=base, author=self.user)
+        c2 = doc.commit(description="Commit #3", text=u"""
+Line #1
+Line #2 is cool
+Line #3
+""", parent=base, author=self.user)
+        self.assertEqual(doc.change_set.count(), 5)
+        self.assertTextEqual(doc.materialize(), u"""
+Line #1
+<<<<<<<
+Line #2 is hot
+=======
+Line #2 is cool
+>>>>>>>
+Line #3
+""")
+
+    def test_multiply_parallel_commits(self):
+        doc = Document.objects.create(name=u"Sample Document", creator=self.user)
+        self.assert_(doc.head is not None)
+        c1 = doc.commit(description="Commit A1", text=u"""
+Line #1
+
+Line #2
+
+Line #3
+""", author=self.user)
+        c2 = doc.commit(description="Commit A2", text=u"""
+Line #1 *
+
+Line #2
+
+Line #3
+""", author=self.user)
+        c3 = doc.commit(description="Commit B1", text=u"""
+Line #1
+
+Line #2 **
+
+Line #3
+""", parent=c1, author=self.user)
+        c4 = doc.commit(description="Commit C1", text=u"""
+Line #1 *
+
+Line #2
+
+Line #3 ***
+""", parent=c2, author=self.user)
+        self.assertEqual(doc.change_set.count(), 7)
+        self.assertTextEqual(doc.materialize(), u"""
+Line #1 *
+
+Line #2 **
+
+Line #3 ***
+""")
+
diff --git a/apps/dvcs/urls.py b/apps/dvcs/urls.py
new file mode 100644
index 00000000..d1e1e296
--- /dev/null
+++ b/apps/dvcs/urls.py
@@ -0,0 +1,6 @@
+# -*- coding: utf-8
+from django.conf.urls.defaults import *
+
+urlpatterns = patterns('dvcs.views',
+    url(r'^data/(?P<document_id>[^/]+)/(?P<version>.*)$', 'document_data', name='storage_document_data'),
+)
diff --git a/apps/dvcs/views.py b/apps/dvcs/views.py
new file mode 100644
index 00000000..7918e96c
--- /dev/null
+++ b/apps/dvcs/views.py
@@ -0,0 +1,21 @@
+# Create your views here.
+from django.views.generic.simple import direct_to_template
+from django import http
+from dvcs.models import Document
+
+def document_list(request, template_name="dvcs/document_list.html"):
+    return direct_to_template(request, template_name, {
+        "documents": Document.objects.all(),
+    })
+
+def document_data(request, document_id, version=None):
+    doc = Document.objects.get(pk=document_id)
+    return http.HttpResponse(doc.materialize(version or None), content_type="text/plain")
+
+def document_history(request, docid, template_name="dvcs/document_history.html"):
+    document = Document.objects.get(pk=docid)
+    return direct_to_template(request, template_name, {
+        "document": document,
+        "changes": document.history(),
+    })
+
diff --git a/redakcja/settings/common.py b/redakcja/settings/common.py
index 8d032ef6..587374be 100644
--- a/redakcja/settings/common.py
+++ b/redakcja/settings/common.py
@@ -117,6 +117,7 @@ INSTALLED_APPS = (
     'south',
     'sorl.thumbnail',
     'filebrowser',
+    'dvcs',
 
     'wiki',
     'toolbar',
@@ -145,3 +146,4 @@ try:
     from redakcja.settings.compress import *
 except ImportError:
     pass
+
diff --git a/redakcja/urls.py b/redakcja/urls.py
index dd7f884d..20994ce1 100644
--- a/redakcja/urls.py
+++ b/redakcja/urls.py
@@ -20,6 +20,7 @@ urlpatterns = patterns('',
 
     url(r'^$', 'django.views.generic.simple.redirect_to', {'url': '/documents/'}),
     url(r'^documents/', include('wiki.urls')),
+    url(r'^storage/', include('dvcs.urls')),
 
     # Static files (should be served by Apache)
     url(r'^%s(?P<path>.+)$' % settings.MEDIA_URL[1:], 'django.views.static.serve',
-- 
2.20.1