Optimise getting the pipeline status of commits

This adds an optimised way of getting the latest pipeline status for a
list of Commit objects (or just a single one).

1 files changed, 44 insertions, 0 deletions

diff --git a/app/models/commit_collection.rb b/app/models/commit_collection.rb
new file mode 100644
index 00000000000..dd93af9df64
--- /dev/null
+++ b/app/models/commit_collection.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+# A collection of Commit instances for a specific project and Git reference.
+class CommitCollection
+  include Enumerable
+
+  attr_reader :project, :ref, :commits
+
+  # project - The project the commits belong to.
+  # commits - The Commit instances to store.
+  # ref - The name of the ref (e.g. "master").
+  def initialize(project, commits, ref = nil)
+    @project = project
+    @commits = commits
+    @ref = ref
+  end
+
+  def each(&block)
+    commits.each(&block)
+  end
+
+  # Sets the pipeline status for every commit.
+  #
+  # Setting this status ahead of time removes the need for running a query for
+  # every commit we're displaying.
+  def with_pipeline_status
+    statuses = project.pipelines.latest_status_per_commit(map(&:id), ref)
+
+    each do |commit|
+      commit.set_status_for_ref(ref, statuses[commit.id])
+    end
+
+    self
+  end
+
+  def respond_to_missing?(message, inc_private = false)
+    commits.respond_to?(message, inc_private)
+  end
+
+  # rubocop:disable GitlabSecurity/PublicSend
+  def method_missing(message, *args, &block)
+    commits.public_send(message, *args, &block)
+  end
+end