Add support for handling multiple branches

Change the data structure to support multiple branches. At the top level
there is a set list of Branch objects, and then a LayerBranch object
between each layer and the maintainers, dependencies, recipes and
machines, so that the set of each can be different per branch. The
branch is a session option, and can be selected via a drop-down that is
shown for all pages.

Additionally, with this change we avoid the need to run the update
script within a build environment set up with oe-init-build-env - since
we need a specific version of BitBake per branch we now use our own copy
of BitBake which is fetched by the script itself. The update script will
need to be called multiple times however - once per branch.

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>

16 files changed, 337 insertions, 178 deletions

diff --git a/layerindex/admin.py b/layerindex/admin.py
index 5e94944268..00ea64f302 100644
--- a/layerindex/admin.py
+++ b/layerindex/admin.py
@@ -14,34 +14,39 @@ class LayerMaintainerInline(admin.StackedInline):
 
 class LayerDependencyInline(admin.StackedInline):
     model = LayerDependency
-    fk_name = 'layer'
+
+class BranchAdmin(CompareVersionAdmin):
+    model = Branch
 
 class LayerItemAdmin(CompareVersionAdmin):
     list_filter = ['status', 'layer_type']
     save_as = True
     search_fields = ['name', 'summary']
-    readonly_fields = ['vcs_last_fetch', 'vcs_last_rev', 'vcs_last_commit']
     formfield_overrides = {
         models.URLField: {'widget': TextInput(attrs={'size':'100'})},
         models.CharField: {'widget': TextInput(attrs={'size':'100'})},
     }
+
+class LayerBranchAdmin(CompareVersionAdmin):
+    list_filter = ['layer__name']
+    readonly_fields = ['layer', 'branch', 'vcs_last_fetch', 'vcs_last_rev', 'vcs_last_commit']
     inlines = [
-        LayerMaintainerInline,
         LayerDependencyInline,
+        LayerMaintainerInline,
     ]
 
 class LayerMaintainerAdmin(CompareVersionAdmin):
-    list_filter = ['status', 'layer__name']
+    list_filter = ['status', 'layerbranch__layer__name']
 
 class LayerDependencyAdmin(CompareVersionAdmin):
-    list_filter = ['layer__name']
+    list_filter = ['layerbranch__layer__name']
 
 class LayerNoteAdmin(CompareVersionAdmin):
     list_filter = ['layer__name']
 
 class RecipeAdmin(admin.ModelAdmin):
     search_fields = ['filename', 'pn']
-    list_filter = ['layer__name']
+    list_filter = ['layerbranch__layer__name', 'layerbranch__branch__name']
     readonly_fields = [fieldname for fieldname in Recipe._meta.get_all_field_names() if fieldname != 'recipefiledependency']
     def has_add_permission(self, request, obj=None):
         return False
@@ -50,14 +55,16 @@ class RecipeAdmin(admin.ModelAdmin):
 
 class MachineAdmin(admin.ModelAdmin):
     search_fields = ['name']
-    list_filter = ['layer__name']
+    list_filter = ['layerbranch__layer__name', 'layerbranch__branch__name']
     readonly_fields = Machine._meta.get_all_field_names()
     def has_add_permission(self, request, obj=None):
         return False
     def has_delete_permission(self, request, obj=None):
         return False
 
+admin.site.register(Branch, BranchAdmin)
 admin.site.register(LayerItem, LayerItemAdmin)
+admin.site.register(LayerBranch, LayerBranchAdmin)
 admin.site.register(LayerMaintainer, LayerMaintainerAdmin)
 admin.site.register(LayerDependency, LayerDependencyAdmin)
 admin.site.register(LayerNote, LayerNoteAdmin)
diff --git a/layerindex/context_processors.py b/layerindex/context_processors.py
new file mode 100644
index 0000000000..8e2c4e7ad6
--- /dev/null
+++ b/layerindex/context_processors.py
@@ -0,0 +1,16 @@
+# layerindex-web - custom context processor
+#
+# Copyright (C) 2013 Intel Corporation
+#
+# Licensed under the MIT license, see COPYING.MIT for details
+
+from layerindex.models import Branch
+
+def layerindex_context(request):
+    current_branch = request.session.get('branch', None)
+    if not current_branch:
+        current_branch = 'master'
+    return {
+        'all_branches': Branch.objects.all(),
+        'current_branch': current_branch,
+    }
\ No newline at end of file
diff --git a/layerindex/detail.html b/layerindex/detail.html
index 102cda1981..268335f942 100644
--- a/layerindex/detail.html
+++ b/layerindex/detail.html
@@ -50,6 +50,13 @@
         </div> <!-- end of container-fluid -->
 
         <div class="container-fluid">
+            {% if not layerbranch %}
+            <div class="row-fluid">
+                <div class="alert alert-error">
+                    This layer does not exist for branch {{ current_branch }}.
+                </div>
+            </div>
+            {% endif %}
             <div class="row-fluid">
                 {% for note in layeritem.layernote_set.all %}
                     <div class="alert">
@@ -95,24 +102,25 @@
                     {% if layeritem.vcs_subdir %}
                         <h4>Subdirectory</h4>
                         <p><span data-toggle="tooltip" title="Select subdirectory"><i class="icon-circle-arrow-right selectallicon" for="vcs_subdir" id="vcs_subdir_select"></i></span><span id="vcs_subdir" class="copyable">{{ layeritem.vcs_subdir }}</span>
-                            {% if layeritem.tree_url %}
+                            {% if layerbranch.tree_url %}
                                 <span class="label label-info">
-                                    <a href="{{ layeritem.tree_url }}">web subdirectory</a>
+                                    <a href="{{ layerbranch.tree_url }}">web subdirectory</a>
                                 </span>
                             {% endif %}
                         </p>
                     {% endif %}
 
-                    {% if layeritem.vcs_last_commit %}
+                    {% if layerbranch.vcs_last_commit %}
                     <p>
-                    <span class="muted"><small>Last commit: {{ layeritem.vcs_last_commit|timesince }} ago</small></span>
+                    <span class="muted"><small>Last commit: {{ layerbranch.vcs_last_commit|timesince }} ago</small></span>
                     </p>
                     {% endif %}
 
-                    <h3>{% if layeritem.active_maintainers|length = 1 %}Maintainer{% else %}Maintainers{% endif %}</h3>
+                    {% if layerbranch.active_maintainers.count > 0 %}
+                    <h3>{% if layerbranch.active_maintainers|length = 1 %}Maintainer{% else %}Maintainers{% endif %}</h3>
 
                     <ul>
-                        {% for maintainer in layeritem.active_maintainers %}
+                        {% for maintainer in layerbranch.active_maintainers %}
                         <li>
                             {{ maintainer.name }}
                             {% if maintainer.responsibility %}
@@ -125,16 +133,17 @@
                         </li>
                         {% endfor %}
                     </ul>
+                    {% endif %}
 
                 </div> <!-- end of span7 -->
 
                 <div class="span4 pull-right description">
-                    {% if layeritem.dependencies_set.all %}
+                    {% if layerbranch.dependencies_set.count > 0 %}
                          <div class="well dependency-well">
                             <h3>Dependencies </h3>
                             <p>The {{ layeritem.name }} layer depends upon:</p>
                             <ul>
-                                {% for dep in layeritem.dependencies_set.all %}
+                                {% for dep in layerbranch.dependencies_set.all %}
                                     <li><a href="{% url layer_item dep.dependency.name %}">{{ dep.dependency.name }}</a></li>
                                 {% endfor %}
                             </ul>
@@ -145,11 +154,11 @@
             </div>  <!-- end of row-fluid -->
         </div> <!-- end of container-fluid -->
 
-        {% if layeritem.status = 'N' %}
+        {% if layeritem.status = 'N' and layerbranch %}
             <div class="container-fluid" style="margin-bottom:1em;">
                 {% if layeritem.vcs_web_file_base_url %}
                 <span class="label label-important">
-                    <a href="{{ layeritem.test_file_url }}">test file link</a>
+                    <a href="{{ layerbranch.test_file_url }}">test file link</a>
                 </span>
                 {% else %}
                 <span class="label">
@@ -158,7 +167,7 @@
                 {% endif %}
                 {% if layeritem.vcs_web_tree_base_url %}
                 <span class="label label-important">
-                    <a href="{{ layeritem.test_tree_url }}">test tree link</a>
+                    <a href="{{ layerbranch.test_tree_url }}">test tree link</a>
                 </span>
                 {% else %}
                 <span class="label">
@@ -167,7 +176,7 @@
                 {% endif %}
             </div>
         {% else %}
-        {% if layeritem.machine_set.count > 0 %}
+        {% if layerbranch.machine_set.count > 0 %}
         <div class="container-fluid" style="margin-bottom:1em;">
             <div class="row-fluid">
                 <div class="navbar">
@@ -178,7 +187,7 @@
 
                 <table class="table table-bordered">
                     <tbody>
-                        {% for machine in layeritem.machine_set.all %}
+                        {% for machine in layerbranch.machine_set.all %}
                             <tr>
                                 <td><a href="{{ machine.vcs_web_url }}">{{ machine.name }}</a></td>
                                 <td>{{ machine.description }}</td>
@@ -190,6 +199,7 @@
          </div>
         {% endif %}
 
+        {% if layerbranch.recipe_set.count > 0 %}
         <div class="container-fluid" style="margin-bottom:1em;">
             <div class="row-fluid">
                 <div class="navbar">
@@ -217,7 +227,7 @@
                             </tr>
                         </thead>
                         <tbody>
-                            {% for recipe in layeritem.sorted_recipes %}
+                            {% for recipe in layerbranch.sorted_recipes %}
                                 <tr>
                                     <td><a href="{% url recipe recipe.id %}">{{ recipe.name }}</a></td>
                                     <td>{{ recipe.pv }}</td>
@@ -229,6 +239,7 @@
                 </div>
         </div>
         {% endif %}
+        {% endif %}
 
 {% endautoescape %}
 
diff --git a/layerindex/editlayer.html b/layerindex/editlayer.html
index 5f6b691197..9c65c84ffc 100644
--- a/layerindex/editlayer.html
+++ b/layerindex/editlayer.html
@@ -180,35 +180,35 @@
         if( repoval.startsWith('git://git.openembedded.org/') ) {
             reponame = repoval.replace(/^.*\//, '')
             $('#id_vcs_web_url').val('http://cgit.openembedded.org/cgit.cgi/' + reponame)
-            $('#id_vcs_web_tree_base_url').val('http://cgit.openembedded.org/cgit.cgi/' + reponame + '/tree/')
-            $('#id_vcs_web_file_base_url').val('http://cgit.openembedded.org/cgit.cgi/' + reponame + '/tree/')
+            $('#id_vcs_web_tree_base_url').val('http://cgit.openembedded.org/cgit.cgi/' + reponame + '/tree/%path%?h=%branch%')
+            $('#id_vcs_web_file_base_url').val('http://cgit.openembedded.org/cgit.cgi/' + reponame + '/tree/%path%?h=%branch%')
         }
         else if( repoval.indexOf('git.yoctoproject.org/') > -1 ) {
             reponame = repoval.replace(/^.*\//, '')
             $('#id_vcs_web_url').val('http://git.yoctoproject.org/cgit/cgit.cgi/' + reponame)
-            $('#id_vcs_web_tree_base_url').val('http://git.yoctoproject.org/cgit/cgit.cgi/' + reponame + '/tree/')
-            $('#id_vcs_web_file_base_url').val('http://git.yoctoproject.org/cgit/cgit.cgi/' + reponame + '/tree/')
+            $('#id_vcs_web_tree_base_url').val('http://git.yoctoproject.org/cgit/cgit.cgi/' + reponame + '/tree/%path%?h=%branch%')
+            $('#id_vcs_web_file_base_url').val('http://git.yoctoproject.org/cgit/cgit.cgi/' + reponame + '/tree/%path%?h=%branch%')
         }
         else if( repoval.indexOf('github.com/') > -1 ) {
             reponame = repoval.replace(/^.*github.com\//, '')
             reponame = reponame.replace(/.git$/, '')
             $('#id_vcs_web_url').val('http://github.com/' + reponame)
-            $('#id_vcs_web_tree_base_url').val('http://github.com/' + reponame + '/tree/master/')
-            $('#id_vcs_web_file_base_url').val('http://github.com/' + reponame + '/blob/master/')
+            $('#id_vcs_web_tree_base_url').val('http://github.com/' + reponame + '/tree/%branch%/')
+            $('#id_vcs_web_file_base_url').val('http://github.com/' + reponame + '/blob/%branch%/')
         }
         else if( repoval.indexOf('gitorious.org/') > -1 ) {
             reponame = repoval.replace(/^.*gitorious.org\//, '')
             reponame = reponame.replace(/.git$/, '')
             $('#id_vcs_web_url').val('http://gitorious.org/' + reponame)
-            $('#id_vcs_web_tree_base_url').val('http://gitorious.org/' + reponame + '/trees/master/')
-            $('#id_vcs_web_file_base_url').val('http://gitorious.org/' + reponame + '/blobs/master/')
+            $('#id_vcs_web_tree_base_url').val('http://gitorious.org/' + reponame + '/trees/%branch%/')
+            $('#id_vcs_web_file_base_url').val('http://gitorious.org/' + reponame + '/blobs/%branch%/')
         }
         else if( repoval.indexOf('bitbucket.org/') > -1 ) {
             reponame = repoval.replace(/^.*bitbucket.org\//, '')
             reponame = reponame.replace(/.git$/, '')
             $('#id_vcs_web_url').val('http://bitbucket.org/' + reponame)
-            $('#id_vcs_web_tree_base_url').val('http://bitbucket.org/' + reponame + '/src/master/%path%?at=master')
-            $('#id_vcs_web_file_base_url').val('http://bitbucket.org/' + reponame + '/src/master/%path%?at=master')
+            $('#id_vcs_web_tree_base_url').val('http://bitbucket.org/' + reponame + '/src/%branch%/%path%?at=%branch%')
+            $('#id_vcs_web_file_base_url').val('http://bitbucket.org/' + reponame + '/src/%branch%/%path%?at=%branch%')
         }
     };
 
diff --git a/layerindex/fixtures/initial_data.json b/layerindex/fixtures/initial_data.json
new file mode 100644
index 0000000000..36072a5f89
--- /dev/null
+++ b/layerindex/fixtures/initial_data.json
@@ -0,0 +1,10 @@
+[
+  {
+    "model": "layerindex.branch",
+    "pk": 1,
+    "fields": {
+      "name": "master",
+      "bitbake_branch": "master"
+    }
+  }
+]
\ No newline at end of file
diff --git a/layerindex/forms.py b/layerindex/forms.py
index bc1134edae..5932647dd0 100644
--- a/layerindex/forms.py
+++ b/layerindex/forms.py
@@ -4,7 +4,7 @@
 #
 # Licensed under the MIT license, see COPYING.MIT for details
 
-from layerindex.models import LayerItem, LayerMaintainer, LayerNote
+from layerindex.models import LayerItem, LayerBranch, LayerMaintainer, LayerNote
 from django import forms
 from django.core.validators import URLValidator, RegexValidator, email_re
 from django.forms.models import inlineformset_factory
@@ -42,7 +42,7 @@ class BaseLayerMaintainerFormSet(forms.models.BaseInlineFormSet):
             f.required = True
         return f
 
-LayerMaintainerFormSet = inlineformset_factory(LayerItem, LayerMaintainer, form=LayerMaintainerForm, formset=BaseLayerMaintainerFormSet,  can_delete=False, extra=10, max_num=10)
+LayerMaintainerFormSet = inlineformset_factory(LayerBranch, LayerMaintainer, form=LayerMaintainerForm, formset=BaseLayerMaintainerFormSet,  can_delete=False, extra=10, max_num=10)
 
 class EditLayerForm(forms.ModelForm):
     # Additional form fields
@@ -53,10 +53,11 @@ class EditLayerForm(forms.ModelForm):
         model = LayerItem
         fields = ('name', 'layer_type', 'summary', 'description', 'vcs_url', 'vcs_subdir', 'vcs_web_url', 'vcs_web_tree_base_url', 'vcs_web_file_base_url', 'usage_url', 'mailing_list_url')
 
-    def __init__(self, user, *args, **kwargs):
+    def __init__(self, user, layerbranch, *args, **kwargs):
         super(self.__class__, self).__init__(*args, **kwargs)
+        self.layerbranch = layerbranch
         if self.instance.pk:
-            self.fields['deps'].initial = [d.dependency.pk for d in self.instance.dependencies_set.all()]
+            self.fields['deps'].initial = [d.dependency.pk for d in self.layerbranch.dependencies_set.all()]
             del self.fields['captcha']
         else:
             self.fields['deps'].initial = [l.pk for l in LayerItem.objects.filter(name='openembedded-core')]
diff --git a/layerindex/index.html b/layerindex/index.html
index d6b192ddad..461252ad7e 100644
--- a/layerindex/index.html
+++ b/layerindex/index.html
@@ -19,7 +19,7 @@
 {% block content %}
 {% autoescape on %}
 
-{% if layer_list %}
+{% if layerbranch_list %}
     <div class="row-fluid">
         <div class="span9 offset1">
 
@@ -68,22 +68,22 @@
                 </thead>
 
                 <tbody>
-                    {% for layeritem in layer_list %}
-                    <tr class="layertype_{{ layeritem.layer_type }}">
-                        <td><a href="{% url layer_item layeritem.name %}">{{ layeritem.name }}</a></td>
-                        <td>{{ layeritem.summary }}</td>
-                        <td>{{ layeritem.get_layer_type_display }}</td>
+                    {% for layerbranch in layerbranch_list %}
+                    <tr class="layertype_{{ layerbranch.layer.layer_type }}">
+                        <td><a href="{% url layer_item layerbranch.layer.name %}">{{ layerbranch.layer.name }}</a></td>
+                        <td>{{ layerbranch.layer.summary }}</td>
+                        <td>{{ layerbranch.layer.get_layer_type_display }}</td>
                         <td class="showRollie">
-                            {{ layeritem.vcs_url }}
-                                {% if layeritem.vcs_web_url %}
-                                <a class="rollie" href="{{ layeritem.vcs_web_url }}">
+                            {{ layerbranch.layer.vcs_url }}
+                                {% if layerbranch.layer.vcs_web_url %}
+                                <a class="rollie" href="{{ layerbranch.layer.vcs_web_url }}">
                                 <span class="label label-info">
                                     web repo
                                 </span>
                                 </a>
                                 {% endif %}
-                                {% if layeritem.tree_url %}
-                                <a class="rollie" href="{{ layeritem.tree_url }}">
+                                {% if layerbranch.tree_url %}
+                                <a class="rollie" href="{{ layerbranch.tree_url }}">
                                 <span class="label label-info">
                                     tree
                                 </span>
diff --git a/layerindex/machines.html b/layerindex/machines.html
index cfbca56eb1..7cade25011 100644
--- a/layerindex/machines.html
+++ b/layerindex/machines.html
@@ -52,7 +52,7 @@
                             <tr>
                                 <td><a href="{{ machine.vcs_web_url }}">{{ machine.name }}</a></td>
                                 <td>{{ machine.description }}</td>
-                                <td><a href="{% url layer_item machine.layer.name %}">{{ machine.layer.name }}</a></td>
+                                <td><a href="{% url layer_item machine.layerbranch.layer.name %}">{{ machine.layerbranch.layer.name }}</a></td>
                             </tr>
                         {% endfor %}
                     </tbody>
diff --git a/layerindex/models.py b/layerindex/models.py
index ee5a063b2f..a32a0b052a 100644
--- a/layerindex/models.py
+++ b/layerindex/models.py
@@ -9,6 +9,18 @@ from datetime import datetime
 from django.contrib.auth.models import User
 from django.core.urlresolvers import reverse
 import os.path
+import re
+
+class Branch(models.Model):
+    name = models.CharField(max_length=50)
+    bitbake_branch = models.CharField(max_length=50)
+
+    class Meta:
+        verbose_name_plural = "Branches"
+
+    def __unicode__(self):
+        return self.name
+
 
 class LayerItem(models.Model):
     LAYER_STATUS_CHOICES = (
@@ -27,9 +39,6 @@ class LayerItem(models.Model):
     layer_type = models.CharField(max_length=1, choices=LAYER_TYPE_CHOICES)
     summary = models.CharField(max_length=200, help_text='One-line description of the layer')
     description = models.TextField()
-    vcs_last_fetch = models.DateTimeField('Last successful fetch', blank=True, null=True)
-    vcs_last_rev = models.CharField('Last revision fetched', max_length=80, blank=True)
-    vcs_last_commit = models.DateTimeField('Last commit date', blank=True, null=True)
     vcs_subdir = models.CharField('Repository subdirectory', max_length=40, blank=True, help_text='Subdirectory within the repository where the layer is located, if not in the root (usually only used if the repository contains more than one layer)')
     vcs_url = models.CharField('Repository URL', max_length=200, help_text='Fetch/clone URL of the repository')
     vcs_web_url = models.URLField('Repository web interface URL', blank=True, help_text='URL of the web interface for browsing the repository, if any')
@@ -47,28 +56,75 @@ class LayerItem(models.Model):
     def change_status(self, newstatus, username):
         self.status = newstatus
 
+    def get_layerbranch(self, branchname):
+        res = list(self.layerbranch_set.filter(branch__name=branchname)[:1])
+        if res:
+            return res[0]
+        return None
+
+    def active_maintainers(self):
+        matches = None
+        for layerbranch in self.layerbranch_set.all():
+            branchmatches = layerbranch.layermaintainer_set.filter(status='A')
+            if matches:
+                matches |= branchmatches
+            else:
+                matches = branchmatches
+        return matches
+
+    def user_can_edit(self, user):
+        if user.is_authenticated():
+            for maintainer in self.active_maintainers():
+                if maintainer.email == user.email:
+                    return True
+        return False
+
+    def get_absolute_url(self):
+        return reverse('layer_item', args=(self.name,));
+
+    def __unicode__(self):
+        return self.name
+
+
+class LayerBranch(models.Model):
+    layer = models.ForeignKey(LayerItem)
+    branch = models.ForeignKey(Branch)
+    vcs_last_fetch = models.DateTimeField('Last successful fetch', blank=True, null=True)
+    vcs_last_rev = models.CharField('Last revision fetched', max_length=80, blank=True)
+    vcs_last_commit = models.DateTimeField('Last commit date', blank=True, null=True)
+
+    class Meta:
+        verbose_name_plural = "Layer branches"
+
+    def sorted_recipes(self):
+        return self.recipe_set.order_by('filename')
+
+    def active_maintainers(self):
+        return self.layermaintainer_set.filter(status='A')
+
     def _handle_url_path(self, base_url, path):
         if base_url:
-            if self.vcs_subdir:
-                extra_path = self.vcs_subdir + '/' + path
+            if self.layer.vcs_subdir:
+                extra_path = self.layer.vcs_subdir + '/' + path
             else:
                 extra_path = path
+            url = base_url.replace('%branch%', self.branch.name)
             if '%path%' in base_url:
                 if extra_path:
-                    url = re.sub(r'\[([^\]]*%path%[^\]]*)\]', '\\1', base_url)
+                    url = re.sub(r'\[([^\]]*%path%[^\]]*)\]', '\\1', url)
                     return url.replace('%path%', extra_path)
                 else:
-                    url = re.sub(r'\[([^\]]*%path%[^\]]*)\]', '', base_url)
+                    url = re.sub(r'\[([^\]]*%path%[^\]]*)\]', '', url)
                     return url
             else:
-                return base_url + extra_path
+                return url + extra_path
         return None
 
     def tree_url(self, path = ''):
-        return self._handle_url_path(self.vcs_web_tree_base_url, path)
+        return self._handle_url_path(self.layer.vcs_web_tree_base_url, path)
 
     def file_url(self, path = ''):
-        return self._handle_url_path(self.vcs_web_file_base_url, path)
+        return self._handle_url_path(self.layer.vcs_web_file_base_url, path)
 
     def test_tree_url(self):
         return self.tree_url('conf')
@@ -76,24 +132,8 @@ class LayerItem(models.Model):
     def test_file_url(self):
         return self.file_url('conf/layer.conf')
 
-    def sorted_recipes(self):
-        return self.recipe_set.order_by('filename')
-
-    def active_maintainers(self):
-        return self.layermaintainer_set.filter(status='A')
-
-    def user_can_edit(self, user):
-        if user.is_authenticated():
-            for maintainer in self.active_maintainers():
-                if maintainer.email == user.email:
-                    return True
-        return False
-
-    def get_absolute_url(self):
-        return reverse('layer_item', args=(self.name,));
-
     def __unicode__(self):
-        return self.name
+        return "%s: %s" % (self.layer.name, self.branch.name)
 
 
 class LayerMaintainer(models.Model):
@@ -101,7 +141,7 @@ class LayerMaintainer(models.Model):
         ('A', 'Active'),
         ('I', 'Inactive'),
     )
-    layer = models.ForeignKey(LayerItem)
+    layerbranch = models.ForeignKey(LayerBranch)
     name = models.CharField(max_length=255)
     email = models.CharField(max_length=255)
     responsibility = models.CharField(max_length=200, blank=True, help_text='Specific area(s) this maintainer is responsible for, if not the entire layer')
@@ -111,18 +151,18 @@ class LayerMaintainer(models.Model):
         respstr = ""
         if self.responsibility:
             respstr = " (%s)" % self.responsibility
-        return "%s: %s <%s>%s" % (self.layer.name, self.name, self.email, respstr)
+        return "%s: %s <%s>%s" % (self.layerbranch.layer.name, self.name, self.email, respstr)
 
 
 class LayerDependency(models.Model):
-    layer = models.ForeignKey(LayerItem, related_name='dependencies_set')
+    layerbranch = models.ForeignKey(LayerBranch, related_name='dependencies_set')
     dependency = models.ForeignKey(LayerItem, related_name='dependents_set')
 
     class Meta:
         verbose_name_plural = "Layer dependencies"
 
     def __unicode__(self):
-        return "%s depends on %s" % (self.layer.name, self.dependency.name)
+        return "%s depends on %s" % (self.layerbranch.layer.name, self.dependency.name)
 
 
 class LayerNote(models.Model):
@@ -134,7 +174,7 @@ class LayerNote(models.Model):
 
 
 class Recipe(models.Model):
-    layer = models.ForeignKey(LayerItem)
+    layerbranch = models.ForeignKey(LayerBranch)
     filename = models.CharField(max_length=255)
     filepath = models.CharField(max_length=255, blank=True)
     pn = models.CharField(max_length=40, blank=True)
@@ -146,7 +186,7 @@ class Recipe(models.Model):
     homepage = models.URLField(blank=True)
 
     def vcs_web_url(self):
-        url = self.layer.file_url(os.path.join(self.filepath, self.filename))
+        url = self.layerbranch.file_url(os.path.join(self.filepath, self.filename))
         return url or ''
 
     def full_path(self):
@@ -170,7 +210,7 @@ class Recipe(models.Model):
 
 class RecipeFileDependency(models.Model):
     recipe = models.ForeignKey(Recipe)
-    layer = models.ForeignKey(LayerItem, related_name='+')
+    layerbranch = models.ForeignKey(LayerBranch, related_name='+')
     path = models.CharField(max_length=255, db_index=True)
 
     class Meta:
@@ -181,13 +221,13 @@ class RecipeFileDependency(models.Model):
 
 
 class Machine(models.Model):
-    layer = models.ForeignKey(LayerItem)
+    layerbranch = models.ForeignKey(LayerBranch)
     name = models.CharField(max_length=255)
     description = models.CharField(max_length=255)
 
     def vcs_web_url(self):
-        url = self.layer.file_url(os.path.join('conf/machine/%s.conf' % self.name))
+        url = self.layerbranch.file_url(os.path.join('conf/machine/%s.conf' % self.name))
         return url or ''
 
     def __unicode__(self):
-        return '%s (%s)' % (self.name, self.layer.name)
+        return '%s (%s)' % (self.name, self.layerbranch.layer.name)
diff --git a/layerindex/rawrecipes.txt b/layerindex/rawrecipes.txt
index cbb7d67931..c1911c9c97 100644
--- a/layerindex/rawrecipes.txt
+++ b/layerindex/rawrecipes.txt
@@ -1,2 +1,2 @@
-{% for recipe in recipe_list %}{{ recipe.layer.name }}	{{ recipe.pn }}	{{ recipe.pv }}	{{ recipe.full_path }}
+{% for recipe in recipe_list %}{{ recipe.layerbranch.layer.name }}	{{ recipe.pn }}	{{ recipe.pv }}	{{ recipe.full_path }}
 {% endfor %}
diff --git a/layerindex/recipedetail.html b/layerindex/recipedetail.html
index f336ba942d..b0d366a983 100644
--- a/layerindex/recipedetail.html
+++ b/layerindex/recipedetail.html
@@ -32,6 +32,12 @@
                     <li class="active"><a href="#">Recipe</a></li>
                 </ul>
 
+                {% if recipe.layerbranch.branch.name != current_branch %}
+                <div class="alert alert-error">
+                    This recipe record is for a different branch than the one you have selected. To search for the equivalent recipe on the {{ current_branch }} branch, click <a href="{% url recipe_search %}?q={{ recipe.name }}">here</a>.
+                </div>
+                {% endif %}
+
                 <table class="table table-striped table-bordered">
                     <tbody>
                         <tr>
@@ -74,7 +80,7 @@
                         </tr>
                         <tr>
                             <th>Layer</th>
-                            <td><a href="{% url layer_item recipe.layer.name %}">{{ recipe.layer.name }}</a></td>
+                            <td><a href="{% url layer_item recipe.layerbranch.layer.name %}">{{ recipe.layerbranch.layer.name }}</a> ({{ recipe.layerbranch.branch.name}} branch)</td>
                         </tr>
                     </tbody>
                 </table>
diff --git a/layerindex/recipes.html b/layerindex/recipes.html
index f84f604ed3..ccc3b5481f 100644
--- a/layerindex/recipes.html
+++ b/layerindex/recipes.html
@@ -54,7 +54,7 @@
                                 <td><a href="{% url recipe recipe.id %}">{{ recipe.name }}</a></td>
                                 <td>{{ recipe.pv }}</td>
                                 <td>{{ recipe.short_desc }}</td>
-                                <td><a href="{% url layer_item recipe.layer.name %}">{{ recipe.layer.name }}</a></td>
+                                <td><a href="{% url layer_item recipe.layerbranch.layer.name %}">{{ recipe.layerbranch.layer.name }}</a></td>
                             </tr>
                         {% endfor %}
                     </tbody>
diff --git a/layerindex/submitlayer.html b/layerindex/submitlayer.html
index 41b5aa1ec6..274f102e61 100644
--- a/layerindex/submitlayer.html
+++ b/layerindex/submitlayer.html
@@ -21,6 +21,10 @@
         {% endblock %}
 
 
+{% block branch_selector %}
+<li class="disabled"><a href="#">Branch: <b>master</b></a></li>
+{% endblock %}
+
 {% block formtop %}
 <div class="submitformintro">
     <p>Please enter the details for the layer you wish to add to the index.</p>
diff --git a/layerindex/update.py b/layerindex/update.py
index 497445a16c..b7d1ec99be 100755
--- a/layerindex/update.py
+++ b/layerindex/update.py
@@ -108,7 +108,7 @@ def update_recipe_file(data, path, recipe, layerdir_start, repodir):
         RecipeFileDependency.objects.filter(recipe=recipe).delete()
         for filedep in filedeps:
             recipedep = RecipeFileDependency()
-            recipedep.layer = recipe.layer
+            recipedep.layerbranch = recipe.layerbranch
             recipedep.recipe = recipe
             recipedep.path = filedep
             recipedep.save()
@@ -132,30 +132,19 @@ def parse_layer_conf(layerdir, data):
     data = bb.cooker._parse(os.path.join(layerdir, "conf", "layer.conf"), data)
     data.expandVarref('LAYERDIR')
 
-def setup_bitbake_path(basepath):
-    # Set path to bitbake lib dir
-    bitbakedir_env = os.environ.get('BITBAKEDIR', '')
-    if bitbakedir_env and os.path.exists(bitbakedir_env + '/lib/bb'):
-        bitbakepath = bitbakedir_env
-    elif basepath and os.path.exists(basepath + '/bitbake/lib/bb'):
-        bitbakepath = basepath + '/bitbake'
-    elif basepath and os.path.exists(basepath + '/../bitbake/lib/bb'):
-        bitbakepath = os.path.abspath(basepath + '/../bitbake')
-    else:
-        # look for bitbake/bin dir in PATH
-        bitbakepath = None
-        for pth in os.environ['PATH'].split(':'):
-            if os.path.exists(os.path.join(pth, '../lib/bb')):
-                bitbakepath = os.path.abspath(os.path.join(pth, '..'))
-                break
-        if not bitbakepath:
-            if basepath:
-                logger.error("Unable to find bitbake by searching BITBAKEDIR, specified path '%s' or its parent, or PATH" % basepath)
-            else:
-                logger.error("Unable to find bitbake by searching BITBAKEDIR or PATH")
-            sys.exit(1)
-    return bitbakepath
+def get_branch(branchname):
+    from layerindex.models import Branch
+    res = list(Branch.objects.filter(name=branchname)[:1])
+    if res:
+        return res[0]
+    return None
 
+def get_layer(layername):
+    from layerindex.models import LayerItem
+    res = list(LayerItem.objects.filter(name=layername)[:1])
+    if res:
+        return res[0]
+    return None
 
 def main():
     if LooseVersion(git.__version__) < '0.3.1':
@@ -167,6 +156,9 @@ def main():
         usage = """
     %prog [options]""")
 
+    parser.add_option("-b", "--branch",
+            help = "Specify branch to update",
+            action="store", dest="branch", default='master')
     parser.add_option("-l", "--layer",
             help = "Specify layers to update (use commas to separate multiple). Default is all published layers.",
             action="store", dest="layers")
@@ -196,39 +188,16 @@ def main():
 
     from django.core.management import setup_environ
     from django.conf import settings
-    from layerindex.models import LayerItem, Recipe, RecipeFileDependency, Machine
+    from layerindex.models import LayerItem, LayerBranch, Recipe, RecipeFileDependency, Machine
     from django.db import transaction
     import settings
 
     setup_environ(settings)
 
-    if len(sys.argv) > 1:
-        basepath = os.path.abspath(sys.argv[1])
-    else:
-        basepath = None
-    bitbakepath = setup_bitbake_path(None)
-
-    # Skip sanity checks
-    os.environ['BB_ENV_EXTRAWHITE'] = 'DISABLE_SANITY_CHECKS'
-    os.environ['DISABLE_SANITY_CHECKS'] = '1'
-
-    sys.path.extend([bitbakepath + '/lib'])
-    import bb.tinfoil
-    import bb.cooker
-    tinfoil = bb.tinfoil.Tinfoil()
-    tinfoil.prepare(config_only = True)
-
-    logger.setLevel(options.loglevel)
-
-    # Clear the default value of SUMMARY so that we can use DESCRIPTION instead if it hasn't been set
-    tinfoil.config_data.setVar('SUMMARY', '')
-    # Clear the default value of DESCRIPTION so that we can see where it's not set
-    tinfoil.config_data.setVar('DESCRIPTION', '')
-    # Clear the default value of HOMEPAGE ('unknown')
-    tinfoil.config_data.setVar('HOMEPAGE', '')
-    # Set a blank value for LICENSE so that it doesn't cause the parser to die (e.g. with meta-ti -
-    # why won't they just fix that?!)
-    tinfoil.config_data.setVar('LICENSE', '')
+    branch = get_branch(options.branch)
+    if not branch:
+        logger.error("Specified branch %s is not valid" % options.branch)
+        sys.exit(1)
 
     fetchdir = settings.LAYER_FETCH_DIR
     if not fetchdir:
@@ -251,6 +220,8 @@ def main():
     fetchedrepos = []
     failedrepos = []
 
+    bitbakepath = os.path.join(fetchdir, 'bitbake')
+
     if not options.nofetch:
         # Fetch latest metadata from repositories
         for layer in layerquery:
@@ -264,13 +235,57 @@ def main():
                     if not os.path.exists(repodir):
                         out = runcmd("git clone %s %s" % (layer.vcs_url, urldir), fetchdir)
                     else:
-                        out = runcmd("git pull", repodir)
+                        out = runcmd("git fetch", repodir)
                 except Exception as e:
                     logger.error("fetch failed: %s" % str(e))
                     failedrepos.append(layer.vcs_url)
                     continue
                 fetchedrepos.append(layer.vcs_url)
 
+        logger.info("Fetching bitbake from remote repository %s" % settings.BITBAKE_REPO_URL)
+        if not os.path.exists(bitbakepath):
+            out = runcmd("git clone %s %s" % (settings.BITBAKE_REPO_URL, 'bitbake'), fetchdir)
+        else:
+            out = runcmd("git fetch", bitbakepath)
+
+    # Check out the branch of BitBake appropriate for this branch and clean out any stale files (e.g. *.pyc)
+    out = runcmd("git checkout origin/%s" % branch.bitbake_branch, bitbakepath)
+    out = runcmd("git clean -f -x", bitbakepath)
+
+    # Skip sanity checks
+    os.environ['BB_ENV_EXTRAWHITE'] = 'DISABLE_SANITY_CHECKS'
+    os.environ['DISABLE_SANITY_CHECKS'] = '1'
+
+    # Ensure we have OE-Core set up to get some base configuration
+    core_layer = get_layer(settings.CORE_LAYER_NAME)
+    if not core_layer:
+        logger.error("Unable to find core layer %s in database; check CORE_LAYER_NAME setting" % settings.CORE_LAYER_NAME)
+        sys.exit(1)
+    core_urldir = sanitise_path(core_layer.vcs_url)
+    core_repodir = os.path.join(fetchdir, core_urldir)
+    core_layerdir = os.path.join(core_repodir, core_layer.vcs_subdir)
+    out = runcmd("git checkout origin/%s" % options.branch, core_repodir)
+    out = runcmd("git clean -f -x", core_repodir)
+    os.environ['BBPATH'] = str("%s:%s" % (os.path.realpath('.'), core_layerdir))
+
+    sys.path.extend([bitbakepath + '/lib'])
+    import bb.tinfoil
+    import bb.cooker
+    tinfoil = bb.tinfoil.Tinfoil()
+    tinfoil.prepare(config_only = True)
+
+    logger.setLevel(options.loglevel)
+
+    # Clear the default value of SUMMARY so that we can use DESCRIPTION instead if it hasn't been set
+    tinfoil.config_data.setVar('SUMMARY', '')
+    # Clear the default value of DESCRIPTION so that we can see where it's not set
+    tinfoil.config_data.setVar('DESCRIPTION', '')
+    # Clear the default value of HOMEPAGE ('unknown')
+    tinfoil.config_data.setVar('HOMEPAGE', '')
+    # Set a blank value for LICENSE so that it doesn't cause the parser to die (e.g. with meta-ti -
+    # why won't they just fix that?!)
+    tinfoil.config_data.setVar('LICENSE', '')
+
     # Process and extract data from each layer
     for layer in layerquery:
         transaction.enter_transaction_management()
@@ -282,23 +297,51 @@ def main():
                 logger.info("Skipping update of layer %s as fetch of repository %s failed" % (layer.name, layer.vcs_url))
                 transaction.rollback()
                 continue
+
             # Collect repo info
             repo = git.Repo(repodir)
             assert repo.bare == False
-            topcommit = repo.commit('master')
+            try:
+                topcommit = repo.commit('origin/%s' % options.branch)
+            except:
+                logger.info("Skipping update of layer %s - branch %s doesn't exist" % (layer.name, options.branch))
+                transaction.rollback()
+                continue
+
             if layer.vcs_subdir:
                 # Find latest commit in subdirectory
                 # A bit odd to do it this way but apparently there's no other way in the GitPython API
-                for commit in repo.iter_commits(paths=layer.vcs_subdir):
+                for commit in repo.iter_commits('origin/%s' % options.branch, paths=layer.vcs_subdir):
                     topcommit = commit
                     break
 
+            layerbranch = layer.get_layerbranch(options.branch)
+            if not layerbranch:
+                # LayerBranch doesn't exist for this branch, create it
+                layerbranch = LayerBranch()
+                layerbranch.layer = layer
+                layerbranch.branch = branch
+                layerbranch.save()
+
             layerdir = os.path.join(repodir, layer.vcs_subdir)
             layerdir_start = os.path.normpath(layerdir) + os.sep
-            layerrecipes = Recipe.objects.filter(layer=layer)
-            layermachines = Machine.objects.filter(layer=layer)
-            if layer.vcs_last_rev != topcommit.hexsha or options.reload:
-                logger.info("Collecting data for layer %s" % layer.name)
+            layerrecipes = Recipe.objects.filter(layerbranch=layerbranch)
+            layermachines = Machine.objects.filter(layerbranch=layerbranch)
+            if layerbranch.vcs_last_rev != topcommit.hexsha or options.reload:
+                # Check out appropriate branch
+                out = runcmd("git checkout origin/%s" % options.branch, repodir)
+
+                if not os.path.exists(layerdir):
+                    if options.branch == 'master':
+                        logger.error("Subdirectory for layer %s does not exist on master branch!" % layer.name)
+                        transaction.rollback()
+                        continue
+                    else:
+                        logger.info("Skipping update of layer %s for branch %s - subdirectory does not exist on this branch" % (layer.name, options.branch))
+                        transaction.rollback()
+                        continue
+
+                logger.info("Collecting data for layer %s on branch %s" % (layer.name, options.branch))
 
                 # Parse layer.conf files for this layer and its dependencies
                 # This is necessary not just because BBPATH needs to be set in order
@@ -308,16 +351,16 @@ def main():
 
                 config_data_copy = bb.data.createCopy(tinfoil.config_data)
                 parse_layer_conf(layerdir, config_data_copy)
-                for dep in layer.dependencies_set.all():
+                for dep in layerbranch.dependencies_set.all():
                     depurldir = sanitise_path(dep.dependency.vcs_url)
                     deprepodir = os.path.join(fetchdir, depurldir)
                     deplayerdir = os.path.join(deprepodir, dep.dependency.vcs_subdir)
                     parse_layer_conf(deplayerdir, config_data_copy)
                 config_data_copy.delVar('LAYERDIR')
 
-                if layer.vcs_last_rev and not options.reload:
+                if layerbranch.vcs_last_rev and not options.reload:
                     try:
-                        diff = repo.commit(layer.vcs_last_rev).diff(topcommit)
+                        diff = repo.commit(layerbranch.vcs_last_rev).diff(topcommit)
                     except Exception as e:
                         logger.warn("Unable to get diff from last commit hash for layer %s - falling back to slow update: %s" % (layer.name, str(e)))
                         diff = None
@@ -350,7 +393,7 @@ def main():
                             (filepath, filename) = split_bb_file_path(path, subdir_start)
                             if filename:
                                 recipe = Recipe()
-                                recipe.layer = layer
+                                recipe.layerbranch = layerbranch
                                 recipe.filename = filename
                                 recipe.filepath = filepath
                                 update_recipe_file(config_data_copy, os.path.join(layerdir, filepath), recipe, layerdir_start, repodir)
@@ -360,7 +403,7 @@ def main():
                                 machinename = check_machine_conf(path)
                                 if machinename:
                                     machine = Machine()
-                                    machine.layer = layer
+                                    machine.layerbranch = layerbranch
                                     machine.name = machinename
                                     update_machine_conf_file(os.path.join(repodir, path), machine)
                                     machine.save()
@@ -385,7 +428,7 @@ def main():
                                         machine = results[0]
                                         update_machine_conf_file(os.path.join(repodir, path), machine)
                                         machine.save()
-                            deps = RecipeFileDependency.objects.filter(layer=layer).filter(path=path)
+                            deps = RecipeFileDependency.objects.filter(layerbranch=layerbranch).filter(path=path)
                             for dep in deps:
                                 dirtyrecipes.add(dep.recipe)
 
@@ -400,7 +443,7 @@ def main():
                         for f in files:
                             if fnmatch.fnmatch(f, "*.bb"):
                                 recipe = Recipe()
-                                recipe.layer = layer
+                                recipe.layerbranch = layerbranch
                                 recipe.filename = f
                                 recipe.filepath = os.path.relpath(root, layerdir)
                                 update_recipe_file(config_data_copy, root, recipe, layerdir_start, repodir)
@@ -410,19 +453,19 @@ def main():
                                 machinename = check_machine_conf(fullpath)
                                 if machinename:
                                     machine = Machine()
-                                    machine.layer = layer
+                                    machine.layerbranch = layerbranch
                                     machine.name = machinename
                                     update_machine_conf_file(fullpath, machine)
                                     machine.save()
 
                 # Save repo info
-                layer.vcs_last_rev = topcommit.hexsha
-                layer.vcs_last_commit = datetime.fromtimestamp(topcommit.committed_date)
+                layerbranch.vcs_last_rev = topcommit.hexsha
+                layerbranch.vcs_last_commit = datetime.fromtimestamp(topcommit.committed_date)
             else:
-                logger.info("Layer %s is already up-to-date" % layer.name)
+                logger.info("Layer %s is already up-to-date for branch %s" % (layer.name, options.branch))
 
-            layer.vcs_last_fetch = datetime.now()
-            layer.save()
+            layerbranch.vcs_last_fetch = datetime.now()
+            layerbranch.save()
 
             if options.dryrun:
                 transaction.rollback()
diff --git a/layerindex/urls.py b/layerindex/urls.py
index b0160097c4..0bc4bee199 100644
--- a/layerindex/urls.py
+++ b/layerindex/urls.py
@@ -7,7 +7,7 @@
 from django.conf.urls.defaults import *
 from django.views.generic import DetailView, ListView
 from layerindex.models import LayerItem, Recipe
-from layerindex.views import LayerListView, RecipeSearchView, MachineSearchView, PlainTextListView, LayerDetailView, edit_layer_view, delete_layer_view, edit_layernote_view, delete_layernote_view
+from layerindex.views import LayerListView, LayerReviewListView, RecipeSearchView, MachineSearchView, PlainTextListView, LayerDetailView, edit_layer_view, delete_layer_view, edit_layernote_view, delete_layernote_view, switch_branch_view
 
 urlpatterns = patterns('',
     url(r'^$',
@@ -26,9 +26,7 @@ urlpatterns = patterns('',
             template_name='layerindex/machines.html'),
             name='machine_search'),
     url(r'^review/$',
-        ListView.as_view(
-            queryset=LayerItem.objects.order_by('name').filter(status__in='N'),
-            context_object_name='layer_list',
+        LayerReviewListView.as_view(
             template_name='layerindex/index.html'),
             name='layer_list_review'),
     url(r'^layer/(?P<slug>[-\w]+)/$',
@@ -49,6 +47,8 @@ urlpatterns = patterns('',
             template_name='layerindex/recipedetail.html'),
             name='recipe'),
     url(r'^layer/(?P<name>[-\w]+)/publish/$', 'layerindex.views.publish', name="publish"),
+    url(r'^branch/(?P<slug>[-\w]+)/$',
+        switch_branch_view, name="switch_branch"),
     url(r'^raw/recipes.txt$',
         PlainTextListView.as_view(
             queryset=Recipe.objects.order_by('pn', 'layer'),
diff --git a/layerindex/views.py b/layerindex/views.py
index e058d9f343..67fa4be0cc 100644
--- a/layerindex/views.py
+++ b/layerindex/views.py
@@ -9,7 +9,7 @@ from django.http import HttpResponse, HttpResponseRedirect, HttpResponseForbidde
 from django.core.urlresolvers import reverse
 from django.core.exceptions import PermissionDenied
 from django.template import RequestContext
-from layerindex.models import LayerItem, LayerMaintainer, LayerDependency, LayerNote, Recipe, Machine
+from layerindex.models import Branch, LayerItem, LayerMaintainer, LayerBranch, LayerDependency, LayerNote, Recipe, Machine
 from datetime import datetime
 from django.views.generic import DetailView, ListView
 from layerindex.forms import EditLayerForm, LayerMaintainerFormSet, EditNoteForm
@@ -79,39 +79,45 @@ def delete_layer_view(request, template_name, slug):
 def edit_layer_view(request, template_name, slug=None):
     if slug:
         # Edit mode
+        branch = Branch.objects.filter(name=request.session.get('branch', 'master'))[:1].get()
         layeritem = get_object_or_404(LayerItem, name=slug)
         if not (request.user.is_authenticated() and (request.user.has_perm('layerindex.publish_layer') or layeritem.user_can_edit(request.user))):
             raise PermissionDenied
+        layerbranch = get_object_or_404(LayerBranch, layer=layeritem, branch=branch)
         deplistlayers = LayerItem.objects.exclude(id=layeritem.id).order_by('name')
     else:
         # Submit mode
+        branch = Branch.objects.filter(name='master')[:1].get()
         layeritem = LayerItem()
+        layerbranch = LayerBranch(layer=layeritem, branch=branch)
         deplistlayers = LayerItem.objects.all().order_by('name')
 
     if request.method == 'POST':
-        form = EditLayerForm(request.user, request.POST, instance=layeritem)
-        maintainerformset = LayerMaintainerFormSet(request.POST, instance=layeritem)
+        form = EditLayerForm(request.user, layerbranch, request.POST, instance=layeritem)
+        maintainerformset = LayerMaintainerFormSet(request.POST, instance=layerbranch)
         if form.is_valid() and maintainerformset.is_valid():
             with transaction.commit_on_success():
                 form.save()
+                layerbranch.layer = layeritem
+                layerbranch.save()
                 maintainerformset.save()
                 if slug:
                     new_deps = form.cleaned_data['deps']
-                    existing_deps = [deprec.dependency for deprec in layeritem.dependencies_set.all()]
+                    existing_deps = [deprec.dependency for deprec in layerbranch.dependencies_set.all()]
                     for dep in new_deps:
                         if dep not in existing_deps:
                             deprec = LayerDependency()
-                            deprec.layer = layeritem
+                            deprec.layerbranch = layerbranch
                             deprec.dependency = dep
                             deprec.save()
                     for dep in existing_deps:
                         if dep not in new_deps:
-                            layeritem.dependencies_set.filter(dependency=dep).delete()
+                            layerbranch.dependencies_set.filter(dependency=dep).delete()
                 else:
                     # Save dependencies
                     for dep in form.cleaned_data['deps']:
                         deprec = LayerDependency()
-                        deprec.layer = layeritem
+                        deprec.layerbranch = layerbranch
                         deprec.dependency = dep
                         deprec.save()
                     # Send email
@@ -133,8 +139,8 @@ def edit_layer_view(request, template_name, slug=None):
                     return HttpResponseRedirect(reverse('submit_layer_thanks'))
             form.was_saved = True
     else:
-        form = EditLayerForm(request.user, instance=layeritem)
-        maintainerformset = LayerMaintainerFormSet(instance=layeritem)
+        form = EditLayerForm(request.user, layerbranch, instance=layeritem)
+        maintainerformset = LayerMaintainerFormSet(instance=layerbranch)
 
     return render(request, template_name, {
         'form': form,
@@ -145,6 +151,14 @@ def edit_layer_view(request, template_name, slug=None):
 def submit_layer_thanks(request):
     return render(request, 'layerindex/submitthanks.html')
 
+def switch_branch_view(request, slug):
+    branch = get_object_or_404(Branch, name=slug)
+    request.session['branch'] = branch.name
+    return_url = request.META.get('HTTP_REFERER')
+    if not return_url:
+        return_url = reverse('layer_list')
+    return HttpResponseRedirect(return_url)
+
 def about(request):
     return render(request, 'layerindex/about.html')
 
@@ -161,16 +175,20 @@ def _statuschange(request, name, newstatus):
     return HttpResponseRedirect(w.get_absolute_url())
 
 class LayerListView(ListView):
-    context_object_name = 'layer_list'
+    context_object_name = 'layerbranch_list'
 
     def get_queryset(self):
-        return LayerItem.objects.filter(status='P').order_by('name')
+        return LayerBranch.objects.filter(branch__name=self.request.session.get('branch', 'master')).filter(layer__status='P').order_by('layer__name')
 
     def get_context_data(self, **kwargs):
         context = super(LayerListView, self).get_context_data(**kwargs)
         context['layer_type_choices'] = LayerItem.LAYER_TYPE_CHOICES
         return context
 
+class LayerReviewListView(ListView):
+    def get_queryset(self):
+        return LayerBranch.objects.filter(branch__name=self.request.session.get('branch', 'master')).filter(layer__status='N').order_by('layer__name')
+
 class LayerDetailView(DetailView):
     model = LayerItem
     slug_field = 'name'
@@ -190,6 +208,7 @@ class LayerDetailView(DetailView):
         context = super(LayerDetailView, self).get_context_data(**kwargs)
         layer = context['layeritem']
         context['useredit'] = layer.user_can_edit(self.user)
+        context['layerbranch'] = layer.get_layerbranch(self.request.session.get('branch', 'master'))
         return context
 
 class RecipeSearchView(ListView):
@@ -198,11 +217,12 @@ class RecipeSearchView(ListView):
 
     def get_queryset(self):
         query_string = self.request.GET.get('q', '')
+        init_qs = Recipe.objects.filter(layerbranch__branch__name=self.request.session.get('branch', 'master'))
         if query_string.strip():
             entry_query = simplesearch.get_query(query_string, ['pn', 'summary', 'description', 'filename'])
-            return Recipe.objects.filter(entry_query).order_by('pn', 'layer')
+            return init_qs.filter(entry_query).order_by('pn', 'layerbranch__layer')
         else:
-            return Recipe.objects.all().order_by('pn', 'layer')
+            return init_qs.order_by('pn', 'layerbranch__layer')
 
     def get_context_data(self, **kwargs):
         context = super(RecipeSearchView, self).get_context_data(**kwargs)
@@ -215,11 +235,12 @@ class MachineSearchView(ListView):
 
     def get_queryset(self):
         query_string = self.request.GET.get('q', '')
+        init_qs = Machine.objects.filter(layerbranch__branch__name=self.request.session.get('branch', 'master'))
         if query_string.strip():
             entry_query = simplesearch.get_query(query_string, ['name', 'description'])
-            return Machine.objects.filter(entry_query).order_by('name', 'layer')
+            return init_qs.filter(entry_query).order_by('name', 'layerbranch__layer')
         else:
-            return Machine.objects.all().order_by('name', 'layer')
+            return init_qs.order_by('name', 'layerbranch__layer')
 
     def get_context_data(self, **kwargs):
         context = super(MachineSearchView, self).get_context_data(**kwargs)