1 files changed, 82 insertions, 0 deletions
diff --git a/lib/gitlab/gitaly_client/commit_service.rb b/lib/gitlab/gitaly_client/commit_service.rb
new file mode 100644
index 00000000000..470e3ac8779
--- /dev/null
+++ b/lib/gitlab/gitaly_client/commit_service.rb
@@ -0,0 +1,82 @@
+module Gitlab
+  module GitalyClient
+    class CommitService
+      # 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
+
+      def initialize(repository)
+        @gitaly_repo = repository.gitaly_repository
+        @repository = repository
+      end
+
+      def is_ancestor(ancestor_id, child_id)
+        request = Gitaly::CommitIsAncestorRequest.new(
+          repository: @gitaly_repo,
+          ancestor_id: ancestor_id,
+          child_id: child_id
+        )
+
+        GitalyClient.call(@repository.storage, :commit_service, :commit_is_ancestor, request).value
+      end
+
+      def diff_from_parent(commit, options = {})
+        request_params = commit_diff_request_params(commit, options)
+        request_params[:ignore_whitespace_change] = options.fetch(:ignore_whitespace_change, false)
+        request = Gitaly::CommitDiffRequest.new(request_params)
+        response = GitalyClient.call(@repository.storage, :diff_service, :commit_diff, request)
+        Gitlab::Git::DiffCollection.new(GitalyClient::DiffStitcher.new(response), options)
+      end
+
+      def commit_deltas(commit)
+        request = Gitaly::CommitDeltaRequest.new(commit_diff_request_params(commit))
+        response = GitalyClient.call(@repository.storage, :diff_service, :commit_delta, request)
+        response.flat_map do |msg|
+          msg.deltas.map { |d| Gitlab::Git::Diff.new(d) }
+        end
+      end
+
+      def tree_entry(ref, path, limit = nil)
+        request = Gitaly::TreeEntryRequest.new(
+          repository: @gitaly_repo,
+          revision: ref,
+          path: path.dup.force_encoding(Encoding::ASCII_8BIT),
+          limit: limit.to_i
+        )
+
+        response = GitalyClient.call(@repository.storage, :commit_service, :tree_entry, request)
+        entry = response.first
+        return unless entry.oid.present?
+
+        if entry.type == :BLOB
+          rest_of_data = response.reduce("") { |memo, msg| memo << msg.data }
+          entry.data += rest_of_data
+        end
+
+        entry
+      end
+
+      def commit_count(ref)
+        request = Gitaly::CountCommitsRequest.new(
+          repository: @gitaly_repo,
+          revision: ref
+        )
+
+        GitalyClient.call(@repository.storage, :commit_service, :count_commits, request).count
+      end
+
+      private
+
+      def commit_diff_request_params(commit, options = {})
+        parent_id = commit.parents[0]&.id || EMPTY_TREE_ID
+
+        {
+          repository: @gitaly_repo,
+          left_commit_id: parent_id,
+          right_commit_id: commit.id,
+          paths: options.fetch(:paths, [])
+        }
+      end
+    end
+  end
+end