Add component to show the full path of a wiki page when viewing its content

app/assets/stylesheets/pages/wiki.scss

@@ -14,7 +14,8 @@
     font-size: 22px;
   }
 
-  .wiki-last-edit-by {
+  .wiki-last-edit-by, .wiki-page-full-path {
+    display: block;
     color: $gl-gray-light;
 
     strong {

app/models/wiki_page.rb

@@ -88,6 +88,12 @@ class WikiPage
                               end
   end
 
+  # The hierarchy of the directory this page is contained in.
+  def directory
+    dir = wiki.page_title_and_dir(slug).last
+    dir.present? ? dir : '/'
+  end
+
   # The processed/formatted content of this page.
   def formatted_content
     @attributes[:formatted_content] ||= if @page
@@ -100,6 +106,11 @@ class WikiPage
     @attributes[:format] || :markdown
   end
 
+  # The full path for this page, including its filename and extension.
+  def full_path
+    "/#{directory}/#{page.filename}".gsub(/\/+/, '/')
+  end
+
   # The commit message for this page version.
   def message
     version.try(:message)

app/views/projects/wikis/show.html.haml

@@ -8,7 +8,7 @@
 
     .nav-text
       %h2.wiki-page-title= @page.title.capitalize
-
+      %span.wiki-page-full-path= "(#{@page.full_path})"
       %span.wiki-last-edit-by
         Last edited by
         %strong

spec/models/wiki_page_spec.rb

@@ -224,6 +224,46 @@ describe WikiPage, models: true do
     end
   end
 
+  describe '#directory' do
+    context 'when the page is at the root directory' do
+      it 'returns /' do
+        create_page('file', 'content')
+        page = wiki.find_page('file')
+
+        expect(page.directory).to eq('/')
+      end
+    end
+
+    context 'when the page is inside an actual directory' do
+      it 'returns the full directory hierarchy' do
+        create_page('dir_1/dir_1_1/file', 'content')
+        page = wiki.find_page('dir_1/dir_1_1/file')
+
+        expect(page.directory).to eq('dir_1/dir_1_1')
+      end
+    end
+  end
+
+  describe '#full_path' do
+    context 'when the page is at the root directory' do
+      it 'returns /filename.fileextension' do
+        create_page('file', 'content')
+        page = wiki.find_page('file')
+
+        expect(page.full_path).to eq('/file.md')
+      end
+    end
+
+    context 'when the page is inside an actual directory' do
+      it 'returns /directory/filename.fileextension' do
+        create_page('dir/file', 'content')
+        page = wiki.find_page('dir/file')
+
+        expect(page.full_path).to eq('/dir/file.md')
+      end
+    end
+  end
+
   describe '#historical?' do
     before do
       create_page('Update', 'content')