Show git-notes (#6984)

* Show git-notes

* Make git-notes heading text localizable

* Refactor git-notes data fetching to a separate function

* Display the author and time of git notes

* Move note bubble inside the commit bubble

* Revert "Move note bubble inside the commit bubble"

This reverts commit c0951fe0e3.

* Add test for git-notes

* testing ui

* Polish CSS

* Apply suggestions from code review

Co-Authored-By: Lauris BH <lauris@nix.lv>

modules/git/notes.go

@@ -0,0 +1,60 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package git
+
+import (
+	"io/ioutil"
+
+	"gopkg.in/src-d/go-git.v4/plumbing"
+)
+
+// NotesRef is the git ref where Gitea will look for git-notes data.
+// The value ("refs/notes/commits") is the default ref used by git-notes.
+const NotesRef = "refs/notes/commits"
+
+// Note stores information about a note created using git-notes.
+type Note struct {
+	Message []byte
+	Commit  *Commit
+}
+
+// GetNote retrieves the git-notes data for a given commit.
+func GetNote(repo *Repository, commitID string, note *Note) error {
+	notes, err := repo.GetCommit(NotesRef)
+	if err != nil {
+		return err
+	}
+
+	entry, err := notes.GetTreeEntryByPath(commitID)
+	if err != nil {
+		return err
+	}
+
+	blob := entry.Blob()
+	dataRc, err := blob.DataAsync()
+	if err != nil {
+		return err
+	}
+
+	defer dataRc.Close()
+	d, err := ioutil.ReadAll(dataRc)
+	if err != nil {
+		return err
+	}
+	note.Message = d
+
+	commit, err := repo.gogitRepo.CommitObject(plumbing.Hash(notes.ID))
+	if err != nil {
+		return err
+	}
+
+	lastCommits, err := getLastCommitForPaths(commit, "", []string{commitID})
+	if err != nil {
+		return err
+	}
+	note.Commit = convertCommit(lastCommits[commitID])
+
+	return nil
+}