[PATCH v3] gitk: Add a "Copy commit summary" command

[Beat Bolli <dev+git@drbeat.li>]

When referring to earlier commits in commit messages or other text, one
of the established formats is

     <abbrev-sha> ("<summary>", <author-date>)

Add a "Copy commit summary" command to the context menu that puts this
text for the currently selected commit on the clipboard. This makes it
easy for our users to create well-formatted commit references.

The <abbrev-sha> is produced with the %h format specifier to make it
unique. Its minimum length can be controlled with the config setting
core.abbrev.

Signed-off-by: Beat Bolli <dev+git@drbeat.li>
Reviewed-by: Eric Sunshine <sunshine@sunshineco.com>
Reviewed-by: Johannes Sixt <j6t@kdbg.org>
Cc: Paul Mackerras <paulus@samba.org>

---
Changes since v2:
- call git log to produce a unique <abbrev-sha>
- use the short date format

Changes since v1:
- drop the "commit " literal in front of the <abbrev-sha>
---
  gitk-git/gitk | 12 ++++++++++++
  1 file changed, 12 insertions(+)

diff --git a/gitk-git/gitk b/gitk-git/gitk
index 9a2daf3..4915f53 100755
--- a/gitk-git/gitk
+++ b/gitk-git/gitk
@@ -2617,6 +2617,7 @@ proc makewindow {} {
  	{mc "Diff selected -> this" command {diffvssel 1}}
  	{mc "Make patch" command mkpatch}
  	{mc "Create tag" command mktag}
+	{mc "Copy commit summary" command copysummary}
  	{mc "Write commit to file" command writecommit}
  	{mc "Create new branch" command mkbranch}
  	{mc "Cherry-pick this commit" command cherrypick}
@@ -9341,6 +9342,17 @@ proc mktaggo {} {
      mktagcan
  }

+proc copysummary {} {
+    global rowmenuid
+
+    set format "%h (\"%s\", %ad)"
+    set summary [exec git show -s --pretty=format:$format --date=short 
\
+                 $rowmenuid]
+
+    clipboard clear
+    clipboard append $summary
+}
+
  proc writecommit {} {
      global rowmenuid wrcomtop commitinfo wrcomcmd NS

-- 
2.4.0