Added list_pages method to avoid loading all wiki pages content

Inside a wiki, when we show the sidebar or browse to the `pages`,
all page contents are retrieved from Gitaly and that is a waste
of resources, since no content from that pages are going to be
showed.

This MR introduces the method `ProjectWiki#list_pages`,
which uses new wiki_list_pages RPC call to retrieve
pages without content

Also in the `WikisController` we're using the method to show
pages in the sidebar and also on the `pages` page.

1 files changed, 34 insertions, 32 deletions

diff --git a/spec/models/wiki_page_spec.rb b/spec/models/wiki_page_spec.rb
index d5c85c11195..520a06e138e 100644
--- a/spec/models/wiki_page_spec.rb
+++ b/spec/models/wiki_page_spec.rb
@@ -44,47 +44,49 @@ describe WikiPage do
         WikiDirectory.new('dir_2', pages)
       end
 
-      context 'sort by title' do
-        let(:grouped_entries) { described_class.group_by_directory(wiki.pages) }
-        let(:expected_grouped_entries) { [dir_1_1, dir_1, page_dir_2, dir_2, page_1, page_6] }
-
-        it 'returns an array with pages and directories' do
-          grouped_entries.each_with_index do |page_or_dir, i|
-            expected_page_or_dir = expected_grouped_entries[i]
-            expected_slugs = get_slugs(expected_page_or_dir)
-            slugs = get_slugs(page_or_dir)
-
-            expect(slugs).to match_array(expected_slugs)
+      context "#list_pages" do
+        context 'sort by title' do
+          let(:grouped_entries) { described_class.group_by_directory(wiki.list_pages) }
+          let(:expected_grouped_entries) { [dir_1_1, dir_1, page_dir_2, dir_2, page_1, page_6] }
+
+          it 'returns an array with pages and directories' do
+            grouped_entries.each_with_index do |page_or_dir, i|
+              expected_page_or_dir = expected_grouped_entries[i]
+              expected_slugs = get_slugs(expected_page_or_dir)
+              slugs = get_slugs(page_or_dir)
+
+              expect(slugs).to match_array(expected_slugs)
+            end
           end
         end
-      end
 
-      context 'sort by created_at' do
-        let(:grouped_entries) { described_class.group_by_directory(wiki.pages(sort: 'created_at')) }
-        let(:expected_grouped_entries) { [dir_1_1, page_1, dir_1, page_dir_2, dir_2, page_6] }
+        context 'sort by created_at' do
+          let(:grouped_entries) { described_class.group_by_directory(wiki.list_pages(sort: 'created_at')) }
+          let(:expected_grouped_entries) { [dir_1_1, page_1, dir_1, page_dir_2, dir_2, page_6] }
 
-        it 'returns an array with pages and directories' do
-          grouped_entries.each_with_index do |page_or_dir, i|
-            expected_page_or_dir = expected_grouped_entries[i]
-            expected_slugs = get_slugs(expected_page_or_dir)
-            slugs = get_slugs(page_or_dir)
+          it 'returns an array with pages and directories' do
+            grouped_entries.each_with_index do |page_or_dir, i|
+              expected_page_or_dir = expected_grouped_entries[i]
+              expected_slugs = get_slugs(expected_page_or_dir)
+              slugs = get_slugs(page_or_dir)
 
-            expect(slugs).to match_array(expected_slugs)
+              expect(slugs).to match_array(expected_slugs)
+            end
           end
         end
-      end
 
-      it 'returns an array with retained order with directories at the top' do
-        expected_order = ['dir_1/dir_1_1/page_3', 'dir_1/page_2', 'dir_2', 'dir_2/page_4', 'dir_2/page_5', 'page_1', 'page_6']
+        it 'returns an array with retained order with directories at the top' do
+          expected_order = ['dir_1/dir_1_1/page_3', 'dir_1/page_2', 'dir_2', 'dir_2/page_4', 'dir_2/page_5', 'page_1', 'page_6']
 
-        grouped_entries = described_class.group_by_directory(wiki.pages)
+          grouped_entries = described_class.group_by_directory(wiki.list_pages)
 
-        actual_order =
-          grouped_entries.map do |page_or_dir|
-            get_slugs(page_or_dir)
-          end
-          .flatten
-        expect(actual_order).to eq(expected_order)
+          actual_order =
+            grouped_entries.map do |page_or_dir|
+              get_slugs(page_or_dir)
+            end
+            .flatten
+          expect(actual_order).to eq(expected_order)
+        end
       end
     end
   end
@@ -386,7 +388,7 @@ describe WikiPage do
 
     it "deletes the page" do
       @page.delete
-      expect(wiki.pages).to be_empty
+      expect(wiki.list_pages).to be_empty
     end
 
     it "returns true" do