Add pre-commit hook

Check that the code follows a consistant coding style before committing.
The current command will be interrupted if the commit doesn't follow the
code style

This fixes #99

Signed-off-by: Xiang, Haihao <[email protected]>

Author: xhaihao

CONTRIBUTING.md

@@ -4,7 +4,39 @@ Intel-vaapi-driver is an open source project licensed under the [MIT License] (h
 
 ## Coding Style
 
-Intel-vaapi-driver does not have a defined coding style at this time, but that will be updated.
+In our project we follow the Linux coding style with a few changes. You may run 'astyle --style=linux -cnpUH -s4 -M120 <file>'
+to format/indent a single file or run './style_unify' in the top-level directory to handle all .c/.h files in the src directory.
+
+You will fail to commit your patch if your patch doesn't follow the coding style and the pre-commit hook will prompt you to fix
+the coding style.
+
+For example:
+
+```
+Checking coding style...
+
+--- .merge_file_tZMQ4C  2017-03-31 11:02:36.244617415 +0800
++++ /tmp/.merge_file_tZMQ4C.D0V 2017-03-31 11:02:36.274617276 +0800
+@@ -438,8 +438,7 @@ intel_batchbuffer_align(struct intel_bat
+     assert((pad_size & 3) == 0);
+     assert(intel_batchbuffer_space(batch) >= pad_size);
+
+-    while (pad_size >= 4)
+-    {
++    while (pad_size >= 4) {
+         intel_batchbuffer_emit_dword(batch, 0);
+         pad_size -= 4;
+     }
+
+**************************************************************************
+ Coding style error in src/intel_batchbuffer.c
+
+ Please fix the coding style before committing. You may run the command
+ below to fix the coding style from the top-level directory
+
+ astyle --style=linux -cnpUH -s4 -M120 src/intel_batchbuffer.c
+**************************************************************************
+```
 
 ## Certificate of Origin
 

autogen.sh

@@ -6,6 +6,15 @@ test -z "$srcdir" && srcdir=.
 ORIGDIR=`pwd`
 cd "$srcdir"
 
+# install pre-commit hook
+SRC_PRE_COMMIT=hooks/pre-commit.hook
+GIT_PRE_COMMIT=.git/hooks/pre-commit
+
+if [ ! \( -x $GIT_PRE_COMMIT -a -L $GIT_PRE_COMMIT \) ]; then
+    rm -f $GIT_PRE_COMMIT
+    ln -s ../../$SRC_PRE_COMMIT $GIT_PRE_COMMIT
+fi
+
 autoreconf -v --install || exit 1
 cd $ORIGDIR || exit $?
 

hooks/pre-commit.hook

@@ -0,0 +1,37 @@
+#!/bin/sh
+#
+# Use astyle to check the coding style
+#
+
+ASTYLE=astyle
+ASTYLE_PARAMS="--style=linux -cnpUH -s4 -M120"
+
+if [ -z "`which $ASTYLE 2> /dev/null`" ]; then
+    echo "git pre-commit hook:"
+    echo "Don't find $ASTYLE, please install $ASTYLE before committing the changes"
+    exit 1
+fi
+
+echo "Checking coding style..."
+echo ""
+for file in `git diff-index --cached --name-only --diff-filter=ACMR HEAD src/ | grep "\.[ch]$" 2> /dev/null`; do
+    tmp0file=`git checkout-index --temp ${file} | cut -f 1`
+    tmp1file=`mktemp /tmp/${tmp0file}.XXX` || exit 1
+    $ASTYLE $ASTYLE_PARAMS < ${tmp0file} > ${tmp1file} 2> /dev/null
+    diff -up "${tmp0file}" "${tmp1file}"
+    ret=$?
+    rm -f "${tmp0file}" "${tmp1file}"
+    if [ $ret != 0 ]; then
+echo ""
+echo "**************************************************************************"
+echo " Coding style error in $file"
+echo ""
+echo " Please fix the coding style before committing. You may run the command"
+echo " below to fix the coding style from the top-level directory"
+echo ""
+echo " $ASTYLE $ASTYLE_PARAMS $file"
+echo "**************************************************************************"
+        exit 1
+    fi
+done
+echo "PASS!!!"