fix chaining querysets for pagination

diff --git a/apps/catalogue/utils.py b/apps/catalogue/utils.py
index acbd778..145511e 100644 (file)
--- a/apps/catalogue/utils.py
+++ b/apps/catalogue/utils.py
@@ -164,3 +164,33 @@ def async_build_pdf(book_id, customizations, file_name):
     if not DefaultStorage().exists(file_name):
         book.build_pdf(customizations=customizations, file_name=file_name)
     print "done."
+
+
+class MultiQuerySet(object):
+    def __init__(self, *args, **kwargs):
+        self.querysets = args
+        self._count = None
+    
+    def count(self):
+        if not self._count:
+            self._count = sum(len(qs) for qs in self.querysets)
+        return self._count
+    
+    def __len__(self):
+        return self.count()
+        
+    def __getitem__(self, item):
+        indices = (offset, stop, step) = item.indices(self.count())
+        items = []
+        total_len = stop - offset
+        for qs in self.querysets:
+            if len(qs) < offset:
+                offset -= len(qs)
+            else:
+                items += list(qs[offset:stop])
+                if len(items) >= total_len:
+                    return items
+                else:
+                    offset = 0
+                    stop = total_len - len(items)
+                    continue
\ No newline at end of file

diff --git a/apps/catalogue/views.py b/apps/catalogue/views.py
index f1eeab7..c34cf29 100644 (file)
--- a/apps/catalogue/views.py
+++ b/apps/catalogue/views.py
@@ -26,14 +26,14 @@ from django.views.generic.list_detail import object_list
 from ajaxable.utils import LazyEncoder, JSONResponse
 from catalogue import models
 from catalogue import forms
-from catalogue.utils import split_tags, AttachmentHttpResponse, async_build_pdf
+from catalogue.utils import (split_tags, AttachmentHttpResponse,
+    async_build_pdf, MultiQuerySet)
 from catalogue.tasks import touch_tag
 from pdcounter import models as pdcounter_models
 from pdcounter import views as pdcounter_views
 from suggest.forms import PublishingSuggestForm
 from picture.models import Picture
 
-from itertools import chain
 from os import path
 
 staff_required = user_passes_test(lambda user: user.is_staff)
@@ -169,22 +169,20 @@ def tagged_object_list(request, tags=''):
         only_author = len(tags) == 1 and tags[0].category == 'author'
         objects = models.Book.objects.none()
 
-        # Add pictures
-    objects = Picture.tagged.with_all(tags)|objects
+    # Add pictures
+    objects = MultiQuerySet(Picture.tagged.with_all(tags), objects)
 
-    return object_list(
-        request,
-        objects,
-        template_name='catalogue/tagged_object_list.html',
-        extra_context={
+    return render_to_response('catalogue/tagged_object_list.html',
+        {
+            'object_list': objects,
             'categories': categories,
             'only_shelf': only_shelf,
             'only_author': only_author,
             'only_my_shelf': only_my_shelf,
             'formats_form': forms.DownloadFormatsForm(),
             'tags': tags,
-        }
-    )
+        },
+        context_instance=RequestContext(request))
 
 
 def book_fragments(request, book, theme_slug):