Merge branch 'minor_refactoring' into 'master'

Minor refactoring

Add Repository#blob_at_branch method

app/models/repository.rb

@@ -178,4 +178,14 @@ class Repository
 
     Tree.new(self, sha, path)
   end
+
+  def blob_at_branch(branch_name, path)
+     last_commit = commit(branch_name)
+
+     if last_commit
+       blob_at(last_commit.sha, path)
+     else
+       nil
+     end
+  end
 end

app/services/files/create_service.rb

@@ -24,8 +24,7 @@ module Files
         return error("Your changes could not be committed, because file name contains not allowed characters")
       end
 
-      commit = repository.commit(ref)
-      blob = repository.blob_at(commit.sha, file_path)
+      blob = repository.blob_at_branch(ref, file_path)
 
       if blob
         return error("Your changes could not be committed, because file with such name exists")

app/services/files/delete_service.rb

@@ -17,8 +17,7 @@ module Files
         return error("You can only create files if you are on top of a branch")
       end
 
-      commit = repository.commit(ref)
-      blob = repository.blob_at(commit.sha, path)
+      blob = repository.blob_at_branch(ref, path)
 
       unless blob
         return error("You can only edit text files")

app/services/files/update_service.rb

@@ -17,8 +17,7 @@ module Files
         return error("You can only create files if you are on top of a branch")
       end
 
-      commit = repository.commit(ref)
-      blob = repository.blob_at(commit.sha, path)
+      blob = repository.blob_at_branch(ref, path)
 
       unless blob
         return error("You can only edit text files")