Introduce GitOperationService and wrap every

git operation inside GitHooksService. Feedback:

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7237#note_19210942

TODO: Fix tests for update_branch_with_hooks

1 files changed, 168 insertions, 0 deletions

diff --git a/app/services/git_operation_service.rb b/app/services/git_operation_service.rb
new file mode 100644
index 00000000000..88175c6931d
--- /dev/null
+++ b/app/services/git_operation_service.rb
@@ -0,0 +1,168 @@
+
+GitOperationService = Struct.new(:user, :repository) do
+  def add_branch(branch_name, newrev)
+    ref = Gitlab::Git::BRANCH_REF_PREFIX + branch_name
+    oldrev = Gitlab::Git::BLANK_SHA
+
+    with_hooks_and_update_ref(ref, oldrev, newrev)
+  end
+
+  def rm_branch(branch)
+    ref = Gitlab::Git::BRANCH_REF_PREFIX + branch.name
+    oldrev = branch.dereferenced_target.id
+    newrev = Gitlab::Git::BLANK_SHA
+
+    with_hooks_and_update_ref(ref, oldrev, newrev)
+  end
+
+  def add_tag(tag_name, newrev, options = {})
+    ref = Gitlab::Git::TAG_REF_PREFIX + tag_name
+    oldrev = Gitlab::Git::BLANK_SHA
+
+    with_hooks(ref, oldrev, newrev) do |service|
+      raw_tag = repository.rugged.tags.create(tag_name, newrev, options)
+      service.newrev = raw_tag.target_id
+    end
+  end
+
+  # Whenever `source_branch` or `source_commit` is passed, if `branch`
+  # doesn't exist, it would be created from `source_branch` or
+  # `source_commit`. Should only pass one of them, not both.
+  # If `source_project` is passed, and the branch doesn't exist,
+  # it would try to find the source from it instead of current repository.
+  def with_branch(
+    branch_name,
+    source_branch: nil,
+    source_commit: nil,
+    source_project: repository.project)
+
+    if source_commit && source_branch
+      raise ArgumentError, 'Should pass only :source_branch or :source_commit'
+    end
+
+    ref = Gitlab::Git::BRANCH_REF_PREFIX + branch_name
+    oldrev = Gitlab::Git::BLANK_SHA
+
+    if repository.branch_exists?(branch_name)
+      oldrev = newrev = repository.commit(branch_name).sha
+
+    elsif repository.project != source_project
+      unless source_branch
+        raise ArgumentError,
+          'Should also pass :source_branch if' +
+          ' :source_project is different from current project'
+      end
+
+      newrev = source_project.repository.commit(source_branch).try(:sha)
+
+      unless newrev
+        raise Repository::CommitError.new(
+          "Cannot find branch #{branch_name} nor" \
+          " #{source_branch} from" \
+          " #{source_project.path_with_namespace}")
+      end
+
+    elsif source_commit || source_branch
+      newrev = (source_commit || repository.commit(source_branch)).try(:sha)
+
+      unless newrev
+        raise Repository::CommitError.new(
+          "Cannot find branch #{branch_name} nor" \
+          " #{source_commit.try(:sha) || source_branch} from" \
+          " #{repository.project.path_with_namespace}")
+      end
+
+    else # we want an orphan empty branch
+      newrev = Gitlab::Git::BLANK_SHA
+    end
+
+    commit_with_hooks(ref, oldrev, newrev) do
+      if repository.project != source_project
+        repository.fetch_ref(
+          source_project.repository.path_to_repo,
+          "#{Gitlab::Git::BRANCH_REF_PREFIX}#{source_branch}",
+          "#{Gitlab::Git::BRANCH_REF_PREFIX}#{branch_name}"
+        )
+      end
+
+      yield(ref)
+    end
+  end
+
+  private
+
+  def commit_with_hooks(ref, oldrev, newrev)
+    with_hooks_and_update_ref(ref, oldrev, newrev) do |service|
+      was_empty = repository.empty?
+
+      # Make commit
+      nextrev = yield(ref)
+
+      unless nextrev
+        raise Repository::CommitError.new('Failed to create commit')
+      end
+
+      service.newrev = nextrev
+
+      update_ref!(ref, nextrev, newrev)
+
+      # If repo was empty expire cache
+      repository.after_create if was_empty
+      repository.after_create_branch if was_empty ||
+                                        oldrev == Gitlab::Git::BLANK_SHA
+
+      nextrev
+    end
+  end
+
+  def with_hooks_and_update_ref(ref, oldrev, newrev)
+    with_hooks(ref, oldrev, newrev) do |service|
+      update_ref!(ref, newrev, oldrev)
+
+      yield(service) if block_given?
+    end
+  end
+
+  def with_hooks(ref, oldrev, newrev)
+    update_autocrlf_option
+
+    result = nil
+
+    GitHooksService.new.execute(
+      user,
+      repository.path_to_repo,
+      oldrev,
+      newrev,
+      ref) do |service|
+
+      result = yield(service) if block_given?
+    end
+
+    result
+  end
+
+  def update_ref!(name, newrev, oldrev)
+    # We use 'git update-ref' because libgit2/rugged currently does not
+    # offer 'compare and swap' ref updates. Without compare-and-swap we can
+    # (and have!) accidentally reset the ref to an earlier state, clobbering
+    # commits. See also https://github.com/libgit2/libgit2/issues/1534.
+    command = %W[#{Gitlab.config.git.bin_path} update-ref --stdin -z]
+    _, status = Gitlab::Popen.popen(
+      command,
+      repository.path_to_repo) do |stdin|
+      stdin.write("update #{name}\x00#{newrev}\x00#{oldrev}\x00")
+    end
+
+    unless status.zero?
+      raise Repository::CommitError.new(
+        "Could not update branch #{name.sub('refs/heads/', '')}." \
+        " Please refresh and try again.")
+    end
+  end
+
+  def update_autocrlf_option
+    if repository.raw_repository.autocrlf != :input
+      repository.raw_repository.autocrlf = :input
+    end
+  end
+end