#!/bin/bash

repository=":ext:kvangend@umtsmon.cvs.sourceforge.net:/cvsroot/umtsmon"
branch="HEAD"
starttag=""
endtag=""
modules="umtsmon"
usage=1

progname=$(basename $0)
cvs2cl="./cvs2cl.pl"
TMP="/tmp"
sedscript="${TMP}/sedscript_$$"

while [ "$1" != "" ]; do
	usage=0
	case "$1" in
		--repository)	shift;
				repository="$1";
				shift;
				;;
		--branch)	shift;
				branch="$1";
				shift;
				;;
		--start-tag)	shift;
				starttag="$1";
				shift;
				;;
		--end-tag)	shift;
				endtag="$1";
				shift;
				;;
		--modules)	shift;
				modules="$1";
				shift;
				;;
		--help)		usage=1;
				break;;
		*)		echo "$progname: unknown argument: \"$1\"" >&2;
				usage=1;
				break;
				;;
	esac
done

if [ $usage = 0 ]; then

    if [ "${repository}" = "" ]; then
	echo "$progname: You must specify a repository with --repository." >&2
	usage=1
    fi

    if [ "${starttag}" = "" ]; then
	echo "$progname: You must specify a start tag with --start-tag." >&2
	usage=1
    fi

    if [ "${endtag}" = "" ]; then
	echo "$progname: You must specify a repository with --end-tag." >&2
	usage=1
    fi

fi

if [ $usage = 1 ]; then
    cat <<USAGE >&2
Usage: ${progname} [option parameter]...
 options:
  --repository		required
  --branch		not required, default is "HEAD"
  --start-tag		required
  --end-tag		required
  --modules		not required, default is "all"
  --help		displays this message

Each option should be followed by one parameter.  Do not use "=".

$progname is a shell script that generates MontaVista-style changelogs
between two tags in a CVS repository.  The script is really just a
front-end to the opensource cvs2cl.pl script.

$progname has two main advantages over using cvs2cl.pl directly:

1) $progname does not need to have a checked-out copy of the CVS
   repository.  $progname does this by using "cvs rlog" on the
   CVS repository, fixing up the output so that it looks like the
   output of "cvs log" (which is what cvs2cl.pl would normally use
   internally), and feeds it to cvs2cl.pl.

2) $progname works around a fault in cvs2cl.pl.  Repositories that
   have a large number of branch and/or revision tags cause cvs2cl.pl
   to use tremendous amounts of memory.  This often causes the machine
   running cvs2cl.pl to start swapping heavily and thrash.  $progname
   addresses this by stripping out all unnecessary tags from the output
   of "cvs rlog" which is presented as the input to cvs2cl.pl.
   As a result, changelogs that took hours to generate now take just
   a few minutes and are limited by how long it takes to do the
   "cvs rlog".

Example:
  $progname \\
	--start-tag umtsmon0_5 \\
	--end-tag umtsmon0_6rc1

  $progname \\
	--repository :ext:cvs.sh.mvista.com:/export/cvs/mvl-kernel \\
	--branch druid_peak \\
	--start-tag druid_peak_start \\
	--end-tag mvlcge310 \\
	--modules "linux rpm"
USAGE
	exit 1
fi

rcsprefix=$(echo ${repository} | sed "s=.*:\([^:]*\)$=\1/=")

# Generate the sed script to munge output of "cvs rlog".  Grab
# the branch tag, start and end revision tags from the output.
# Discard all other tags.  Note: there probably isn't a symbolic
# tag named "HEAD", but it wont hurt to have it in the sed script.

cat > ${sedscript} <<SEDSCRIPT
\=^RCS file: ${rcsprefix}.*,v$={
	p
	s=^RCS file: ${rcsprefix}\(.*\),v$=Working file: \1=
	s=Attic/==
}
\=^symbolic names:=,\=^[^	]={
	\=	={
		\=^	${starttag}: ={
			p
		}
		\=^	${endtag}: ={
			p
		}
		\=^	${branch}: ={
			p
		}
		d
	}
}
SEDSCRIPT

if [ "${branch}" = "HEAD" ]; then
    rlogrev="${starttag}::${endtag},${endtag}"
    cvs2clfollow="trunk"
else
    rlogrev="${branch},${starttag}::${endtag},${endtag}"
    cvs2clfollow="${branch}"
fi

cat <<HEADER
Changelog for:	${repository}
Branch:		${branch}
Start Tag:	${starttag}
End Tag:	${endtag}
Modules:	${modules}

HEADER

cvs -Q -d${repository} rlog -r${rlogrev} ${modules} 2>/dev/null \
| sed -f $sedscript \
| $cvs2cl \
	--stdin --stdout \
	--separate-header --no-wrap \
	--follow ${cvs2clfollow} --delta ${starttag}:${endtag}

rm -f $sedscript