#!/bin/sh

# A Subversion pre-commit script to test if the files committed or
# modified are canonical XML. Rejects commits if not.

# Based on the example shipped with Subversion. Technical details at
# the end.

REPOS="$1"
TXN="$2"
SVNLOOK=/usr/bin/svnlook
LOGFILE=/tmp/subversion-commit.log

# Exit on all errors.
set -e

LOG=$($SVNLOOK info -t "$TXN" "$REPOS")
FILES=$($SVNLOOK changed -t "$TXN" "$REPOS")

echo "" >> ${LOGFILE}
echo $REPOS >> ${LOGFILE}
echo $TXN >> ${LOGFILE}
echo $LOG >> ${LOGFILE}
filename=0
for file in $FILES; do
   if [ $filename = 1 ]; then
       echo $operation $file >> ${LOGFILE}
       if [ $operation = "A" ] || [ $operation = "U" ]; then
	   tmp=$(mktemp /tmp/.pre-commit.XXXXXXXXXX)
	   $SVNLOOK cat -t "$TXN" $REPOS $file > $tmp
	   xmllint --noout $tmp
	   tmp2=$(mktemp /tmp/.pre-commit.XXXXXXXXXX)
	   xmllint --c14n $tmp > $tmp2
	   difference=$(diff -q -u $tmp $tmp2 || true)
	   rm -f ${tmp} ${tmp2}
	   if [ ! -z "$difference" ]; then
	       echo "File \"$file\" is not canonical XML" >&2
	       exit 3
	   fi
	   filename=0
       fi
   else
       operation=$file
       filename=1
   fi
done

# All checks passed, so allow the commit.
exit 0

# PRE-COMMIT HOOK
#
# The pre-commit hook is invoked before a Subversion txn is
# committed.  Subversion runs this hook by invoking a program
# (script, executable, binary, etc.) named 'pre-commit' (for which
# this file is a template), with the following ordered arguments:
#
#   [1] REPOS-PATH   (the path to this repository)
#   [2] TXN-NAME     (the name of the txn about to be committed)
#
#   [STDIN] LOCK-TOKENS ** the lock tokens are passed via STDIN.
#
#   If STDIN contains the line "LOCK-TOKENS:\n" (the "\n" denotes a
#   single newline), the lines following it are the lock tokens for
#   this commit.  The end of the list is marked by a line containing
#   only a newline character.
#
#   Each lock token line consists of a URI-escaped path, followed
#   by the separator character '|', followed by the lock token string,
#   followed by a newline.
#
# The default working directory for the invocation is undefined, so
# the program should set one explicitly if it cares.
#
# If the hook program exits with success, the txn is committed; but
# if it exits with failure (non-zero), the txn is aborted, no commit
# takes place, and STDERR is returned to the client.   The hook
# program can use the 'svnlook' utility to help it examine the txn.
#
# On a Unix system, the normal procedure is to have 'pre-commit'
# invoke other programs to do the real work, though it may do the
# work itself too.
#
#   ***  NOTE: THE HOOK PROGRAM MUST NOT MODIFY THE TXN, EXCEPT  ***
#   ***  FOR REVISION PROPERTIES (like svn:log or svn:author).   ***
#
#   This is why we recommend using the read-only 'svnlook' utility.
#   In the future, Subversion may enforce the rule that pre-commit
#   hooks should not modify the versioned data in txns, or else come
#   up with a mechanism to make it safe to do so (by informing the
#   committing client of the changes).  However, right now neither
#   mechanism is implemented, so hook writers just have to be careful.
#
# Note that 'pre-commit' must be executable by the user(s) who will
# invoke it (typically the user httpd runs as), and that user must
# have filesystem-level permission to access the repository.
#
# On a Windows system, you should name the hook program
# 'pre-commit.bat' or 'pre-commit.exe',
# but the basic idea is the same.
#
# The hook program typically does not inherit the environment of
# its parent process.  For example, a common problem is for the
# PATH environment variable to not be set to its usual value, so
# that subprograms fail to launch unless invoked via absolute path.
# If you're having unexpected problems with a hook program, the
# culprit may be unusual (or missing) environment variables.
# 
# Here is an example hook script, for a Unix /bin/sh interpreter.
# For more examples and pre-written hooks, see those in
# /usr/share/subversion/hook-scripts, and in the repository at
# http://svn.apache.org/repos/asf/subversion/trunk/tools/hook-scripts/ and
# http://svn.apache.org/repos/asf/subversion/trunk/contrib/hook-scripts/