Merge branch 'sh-rugged-tree-entries' into 'master'

Bring back Rugged implementation of GetTreeEntries

See merge request gitlab-org/gitlab-ce!25674

3 files changed, 116 insertions, 0 deletions

diff --git a/lib/gitlab/git/rugged_impl/repository.rb b/lib/gitlab/git/rugged_impl/repository.rb
index d4500573235..fe0120b1199 100644
--- a/lib/gitlab/git/rugged_impl/repository.rb
+++ b/lib/gitlab/git/rugged_impl/repository.rb
@@ -66,6 +66,11 @@ module Gitlab
         rescue Rugged::ReferenceError
           nil
         end
+
+        # Lookup for rugged object by oid or ref name
+        def lookup(oid_or_ref_name)
+          rugged.rev_parse(oid_or_ref_name)
+        end
       end
     end
   end
diff --git a/lib/gitlab/git/rugged_impl/tree.rb b/lib/gitlab/git/rugged_impl/tree.rb
new file mode 100644
index 00000000000..0ebfd496695
--- /dev/null
+++ b/lib/gitlab/git/rugged_impl/tree.rb
@@ -0,0 +1,105 @@
+# frozen_string_literal: true
+
+# NOTE: This code is legacy. Do not add/modify code here unless you have
+# discussed with the Gitaly team.  See
+# https://docs.gitlab.com/ee/development/gitaly.html#legacy-rugged-code
+# for more details.
+
+module Gitlab
+  module Git
+    module RuggedImpl
+      module Tree
+        module ClassMethods
+          extend ::Gitlab::Utils::Override
+
+          override :tree_entries
+          def tree_entries(repository, sha, path, recursive)
+            if Feature.enabled?(:rugged_tree_entries)
+              tree_entries_from_rugged(repository, sha, path, recursive)
+            else
+              super
+            end
+          end
+
+          def tree_entries_from_rugged(repository, sha, path, recursive)
+            current_path_entries = get_tree_entries_from_rugged(repository, sha, path)
+            ordered_entries = []
+
+            current_path_entries.each do |entry|
+              ordered_entries << entry
+
+              if recursive && entry.dir?
+                ordered_entries.concat(tree_entries_from_rugged(repository, sha, entry.path, true))
+              end
+            end
+
+            # This was an optimization to reduce N+1 queries for Gitaly
+            # (https://gitlab.com/gitlab-org/gitaly/issues/530).  It
+            # used to be done lazily in the view via
+            # TreeHelper#flatten_tree, so it's possible there's a
+            # performance impact by loading this eagerly.
+            rugged_populate_flat_path(repository, sha, path, ordered_entries)
+          end
+
+          def rugged_populate_flat_path(repository, sha, path, entries)
+            entries.each do |entry|
+              entry.flat_path = entry.path
+
+              next unless entry.dir?
+
+              entry.flat_path =
+                if path
+                  File.join(path, rugged_flatten_tree(repository, sha, entry, path))
+                else
+                  rugged_flatten_tree(repository, sha, entry, path)
+                end
+            end
+          end
+
+          # Returns the relative path of the first subdir that doesn't have only one directory descendant
+          def rugged_flatten_tree(repository, sha, tree, root_path)
+            subtree = tree_entries_from_rugged(repository, sha, tree.path, false)
+
+            if subtree.count == 1 && subtree.first.dir?
+              File.join(tree.name, rugged_flatten_tree(repository, sha, subtree.first, root_path))
+            else
+              tree.name
+            end
+          end
+
+          def get_tree_entries_from_rugged(repository, sha, path)
+            commit = repository.lookup(sha)
+            root_tree = commit.tree
+
+            tree = if path
+                     id = find_id_by_path(repository, root_tree.oid, path)
+                     if id
+                       repository.lookup(id)
+                     else
+                       []
+                     end
+                   else
+                     root_tree
+                   end
+
+            tree.map do |entry|
+              current_path = path ? File.join(path, entry[:name]) : entry[:name]
+
+              new(
+                id: entry[:oid],
+                root_id: root_tree.oid,
+                name: entry[:name],
+                type: entry[:type],
+                mode: entry[:filemode].to_s(8),
+                path: current_path,
+                commit_id: sha
+              )
+            end
+          rescue Rugged::ReferenceError
+            []
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/git/tree.rb b/lib/gitlab/git/tree.rb
index 6fcea4e12b4..7e072c5db50 100644
--- a/lib/gitlab/git/tree.rb
+++ b/lib/gitlab/git/tree.rb
@@ -18,6 +18,10 @@ module Gitlab
         def where(repository, sha, path = nil, recursive = false)
           path = nil if path == '' || path == '/'
 
+          tree_entries(repository, sha, path, recursive)
+        end
+
+        def tree_entries(repository, sha, path, recursive)
           wrapped_gitaly_errors do
             repository.gitaly_commit_client.tree_entries(repository, sha, path, recursive)
           end
@@ -95,3 +99,5 @@ module Gitlab
     end
   end
 end
+
+Gitlab::Git::Tree.singleton_class.prepend Gitlab::Git::RuggedImpl::Tree::ClassMethods