#!/bin/sh

# Title: pre-commit
# Author: John Stile
# Data: 20050708
# Mod History:
#    20050708 - Copy into /svn/repos/NAME 

# 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)
#
# 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.
#
# Here is an example hook script, for a Unix /bin/sh interpreter:

########################
# repository
########################
REPOS="$1"
# Transaction
TXN="$2"

########################
#debug
########################
#transaction=`$SVNLOOK  changed -t $TXN $REPO`
#echo "$transaction";

##########################
# user 'god' can do anything
##########################
# User=`svnlook author -t $TXN $REPOS`
# if ( $User == "god" ){ exit 0 }

#################################
# Log message contains some text.
#################################
SVNLOOK=/usr/bin/svnlook
$SVNLOOK log -t "$TXN" "$REPOS" | \
   grep "[a-zA-Z0-9]" > /dev/null || exit 1

########################
# Protect tags directory
########################
# Deny transaction if any line writes to a tages directory that exists.
# tags dir match pattern 
TAGS_REGEX='tags/[^/]\+'
# Get list of transactions in the 'tag' directory 
TAGS_CHANGES=`"$SVNLOOK" changed -t "$TXN" "$REPOS" 2>/dev/null | \
                 awk '{ print $2; }' 2>/dev/null | \
                 grep ^tags/ 2>/dev/null | \
		 sed -e "s!^\($TAGS_REGEX\).*!\1!" | \
		 sort | \
		 uniq`
# Get head revision number
YOUNGEST=`svnlook youngest "$REPOS" 2>/dev/null`
# For every line in transaction,
# check to see if directory in tags exists
for CHANGE in $TAGS_CHANGES; do
  # If directory in tags exists, deny transaction
  if svnlook proplist -r $YOUNGEST "$REPOS" "$CHANGE" >/dev/null 2>&1 ; then
    echo "Cannot modify existing tag: ${tag}" >&2
    exit 1
  fi
done

#######################
# Allow transaction
#######################
exit 0