From 28128ca41c299ea859fd59583a12cd767b1af33f Mon Sep 17 00:00:00 2001
From: Peter Wu <peter@lekensteyn.nl>
Date: Thu, 25 Jun 2015 11:49:16 -0700
Subject: tools/pre-commit: compare files instead of mtime

Instead of unconditionally checking for the file mtime, compare file
contents instead. Perform this check only for invocations via a hook.

While at it, simplify setting defaults for the git directory and the
commit identifier. Support executions via relative paths and update the
help messages on top of the file.

Change-Id: I89c015fe6553ad52e07795683dd88cb219a26ed2
Reviewed-on: https://code.wireshark.org/review/8923
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>
---
 tools/pre-commit | 33 +++++++++++++++++++++------------
 1 file changed, 21 insertions(+), 12 deletions(-)

(limited to 'tools')

diff --git a/tools/pre-commit b/tools/pre-commit
index 9f213a3d15..e83971902e 100755
--- a/tools/pre-commit
+++ b/tools/pre-commit
@@ -1,8 +1,16 @@
 #!/bin/sh
 # Copyright 2013, Alexis La Goutte (See AUTHORS file)
 #
-# For git user: copy pre-commit to .git/hook/ folder
-#   To not launch the script when committing, use --no-verify argument
+# For git user: copy tools/pre-commit to .git/hooks/ folder and make it
+# executable. To bypass it for a single commit, use the --no-verify argument.
+#
+# Alternatively, invoke it directly with the commit ID. Example for checking the
+# last commit:
+#
+#   tools/pre-commit HEAD~
+#
+# Relative paths are also supported. For instance, if you are in epan/, then you
+# could invoke `../tools/pre-commit HEAD` to check for changes to staged files.
 #
 # From
 # http://mark-story.com/posts/view/using-git-commit-hooks-to-prevent-stupid-mistakes
@@ -10,17 +18,18 @@
 
 unset GREP_OPTIONS
 
-if [ -z $GIT_DIR ]; then GIT_DIR=".git"; fi
-
-if [ -z $1 ]; then
-    COMMIT_ID="HEAD"
-else
-    COMMIT_ID=$1
-fi
+# If the commit identifier is not given, use HEAD instead.
+COMMIT_ID="${1:-HEAD}"
+# Path to hook script in the .git directory
+hook_script=${GIT_DIR:-.git}/hooks/pre-commit
 
+# Always start in the root directory of the source tree, this allows for
+# invocations via relative paths (such as ../tools/pre-commit):
+cd "$(git rev-parse --show-toplevel)"
 
-# Check for newer versions of the pre-commit script
-if [ ${GIT_DIR}/hooks/pre-commit -ot ./tools/pre-commit ]; then
+# Check for newer (actually, different) versions of the pre-commit script
+# (but only if invoked as hook, i.e. the commit ID is not given as argument).
+if [ -z "$1" ] && ! cmp -s "$hook_script" tools/pre-commit; then
     echo "Pre-commit hook script is outdated, please update!"
 fi
 
@@ -38,7 +47,7 @@ for FILE in `git diff-index --cached --name-status ${COMMIT_ID} | grep -v "^D" |
     ./tools/fix-encoding-args.pl $FILE  || exit_status=1
 
     #Check if checkfiltername is good
-    ./tools/checkfiltername.pl $FILE  || exit_status=1
+    ./tools/checkfiltername.pl $FILE    || exit_status=1
 
 done
 
-- 
cgit v1.2.3