1 files changed, 66 insertions, 0 deletions
diff --git a/app/models/compare.rb b/app/models/compare.rb
new file mode 100644
index 00000000000..4856510f526
--- /dev/null
+++ b/app/models/compare.rb
@@ -0,0 +1,66 @@
+class Compare
+  delegate :same, :head, :base, to: :@compare
+
+  attr_reader :project
+
+  def self.decorate(compare, project)
+    if compare.is_a?(Compare)
+      compare
+    else
+      self.new(compare, project)
+    end
+  end
+
+  def initialize(compare, project)
+    @compare = compare
+    @project = project
+  end
+
+  def commits
+    @commits ||= Commit.decorate(@compare.commits, project)
+  end
+
+  def start_commit
+    return @start_commit if defined?(@start_commit)
+
+    commit = @compare.base
+    @start_commit = commit ? ::Commit.new(commit, project) : nil
+  end
+
+  def head_commit
+    return @head_commit if defined?(@head_commit)
+
+    commit = @compare.head
+    @head_commit = commit ? ::Commit.new(commit, project) : nil
+  end
+  alias_method :commit, :head_commit
+
+  def base_commit
+    return @base_commit if defined?(@base_commit)
+
+    @base_commit = if start_commit && head_commit
+                     project.merge_base_commit(start_commit.id, head_commit.id)
+                   else
+                     nil
+                   end
+  end
+
+  def raw_diffs(*args)
+    @compare.diffs(*args)
+  end
+
+  def diffs(diff_options = nil)
+    Gitlab::Diff::FileCollection::Compare.new(self,
+      project: project,
+      diff_options: diff_options,
+      diff_refs: diff_refs)
+  end
+
+  def diff_refs
+    Gitlab::Diff::DiffRefs.new(
+      base_sha:  base_commit.try(:sha),
+      start_sha: start_commit.try(:sha),
+      head_sha: commit.try(:sha)
+    )
+  end
+end