Use Gitaly for CommitController#showfeature/use-gitaly-for-commit-show

4 files changed, 61 insertions, 3 deletions

diff --git a/lib/gitlab/git/diff.rb b/lib/gitlab/git/diff.rb
index 2a017c93f57..019be151353 100644
--- a/lib/gitlab/git/diff.rb
+++ b/lib/gitlab/git/diff.rb
@@ -176,9 +176,13 @@ module Gitlab
       def initialize(raw_diff, collapse: false)
         case raw_diff
         when Hash
-          init_from_hash(raw_diff, collapse: collapse)
+          init_from_hash(raw_diff)
+          prune_diff_if_eligible(collapse)
         when Rugged::Patch, Rugged::Diff::Delta
           init_from_rugged(raw_diff, collapse: collapse)
+        when Gitaly::CommitDiffResponse
+          init_from_gitaly(raw_diff)
+          prune_diff_if_eligible(collapse)
         when nil
           raise "Nil as raw diff passed"
         else
@@ -266,13 +270,26 @@ module Gitlab
         @diff = encode!(strip_diff_headers(patch.to_s))
       end
 
-      def init_from_hash(hash, collapse: false)
+      def init_from_hash(hash)
         raw_diff = hash.symbolize_keys
 
         serialize_keys.each do |key|
           send(:"#{key}=", raw_diff[key.to_sym])
         end
+      end
+
+      def init_from_gitaly(diff_msg)
+        @diff = diff_msg.raw_chunks.join
+        @new_path = encode!(diff_msg.to_path.dup)
+        @old_path = encode!(diff_msg.from_path.dup)
+        @a_mode = diff_msg.old_mode.to_s(8)
+        @b_mode = diff_msg.new_mode.to_s(8)
+        @new_file = diff_msg.from_id == BLANK_SHA
+        @renamed_file = diff_msg.from_path != diff_msg.to_path
+        @deleted_file = diff_msg.to_id == BLANK_SHA
+      end
 
+      def prune_diff_if_eligible(collapse = false)
         prune_large_diff! if too_large?
         prune_collapsed_diff! if collapse && collapsible?
       end
diff --git a/lib/gitlab/git/diff_collection.rb b/lib/gitlab/git/diff_collection.rb
index 65e06f5065d..4e45ec7c174 100644
--- a/lib/gitlab/git/diff_collection.rb
+++ b/lib/gitlab/git/diff_collection.rb
@@ -30,7 +30,9 @@ module Gitlab
         elsif @deltas_only
           each_delta(&block)
         else
-          each_patch(&block)
+          Gitlab::GitalyClient.migrate(:commit_raw_diffs) do
+            each_patch(&block)
+          end
         end
       end
 
diff --git a/lib/gitlab/gitaly_client.rb b/lib/gitlab/gitaly_client.rb
index b981a629fb0..5534d4af439 100644
--- a/lib/gitlab/gitaly_client.rb
+++ b/lib/gitlab/gitaly_client.rb
@@ -25,5 +25,19 @@ module Gitlab
     def self.enabled?
       gitaly_address.present?
     end
+
+    def self.feature_enabled?(feature)
+      enabled? && ENV["GITALY_#{feature.upcase}"] == '1'
+    end
+
+    def self.migrate(feature)
+      is_enabled  = feature_enabled?(feature)
+      metric_name = feature.to_s
+      metric_name += "_gitaly" if is_enabled
+
+      Gitlab::Metrics.measure(metric_name) do
+        yield is_enabled
+      end
+    end
   end
 end
diff --git a/lib/gitlab/gitaly_client/commit.rb b/lib/gitlab/gitaly_client/commit.rb
new file mode 100644
index 00000000000..525b8d680e9
--- /dev/null
+++ b/lib/gitlab/gitaly_client/commit.rb
@@ -0,0 +1,25 @@
+module Gitlab
+  module GitalyClient
+    class Commit
+      # The ID of empty tree.
+      # See http://stackoverflow.com/a/40884093/1856239 and https://github.com/git/git/blob/3ad8b5bf26362ac67c9020bf8c30eee54a84f56d/cache.h#L1011-L1012
+      EMPTY_TREE_ID = '4b825dc642cb6eb9a060e54bf8d69288fbee4904'.freeze
+
+      class << self
+        def diff_from_parent(commit, options = {})
+          stub      = Gitaly::Diff::Stub.new(nil, nil, channel_override: GitalyClient.channel)
+          repo      = Gitaly::Repository.new(path: commit.project.repository.path_to_repo)
+          parent    = commit.parents[0]
+          parent_id = parent ? parent.id : EMPTY_TREE_ID
+          request   = Gitaly::CommitDiffRequest.new(
+            repository: repo,
+            left_commit_id: parent_id,
+            right_commit_id: commit.id
+          )
+
+          Gitlab::Git::DiffCollection.new(stub.commit_diff(request), options)
+        end
+      end
+    end
+  end
+end