# Copyright (C) 2007, 2008, 2009 Apple Inc.  All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# 1.  Redistributions of source code must retain the above copyright
#     notice, this list of conditions and the following disclaimer. 
# 2.  Redistributions in binary form must reproduce the above copyright
#     notice, this list of conditions and the following disclaimer in the
#     documentation and/or other materials provided with the distribution. 
# 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
#     its contributors may be used to endorse or promote products derived
#     from this software without specific prior written permission. 
#
# THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

# Module to share code to work with various version control systems.

use strict;
use warnings;

use Cwd qw();  # "qw()" prevents warnings about redefining getcwd() with "use POSIX;"
use File::Basename;
use File::Spec;

BEGIN {
   use Exporter   ();
   our ($VERSION, @ISA, @EXPORT, @EXPORT_OK, %EXPORT_TAGS);
   $VERSION     = 1.00;
   @ISA         = qw(Exporter);
   @EXPORT      = qw(&chdirReturningRelativePath &determineSVNRoot &determineVCSRoot &isGit &isGitDirectory &isSVN &isSVNDirectory &makeFilePathRelative);
   %EXPORT_TAGS = ( );
   @EXPORT_OK   = ();
}

our @EXPORT_OK;

my $isGit;
my $isSVN;
my $gitBranch;
my $isGitBranchBuild;

sub isGitDirectory($)
{
    my ($dir) = @_;
    return system("cd $dir && git rev-parse > /dev/null 2>&1") == 0;
}

sub isGit()
{
    return $isGit if defined $isGit;

    $isGit = isGitDirectory(".");
    return $isGit;
}

sub gitBranch()
{
    unless (defined $gitBranch) {
        chomp($gitBranch = `git symbolic-ref -q HEAD`);
        $gitBranch = "" if exitStatus($?);
        $gitBranch =~ s#^refs/heads/##;
        $gitBranch = "" if $gitBranch eq "master";
    }

    return $gitBranch;
}

sub isGitBranchBuild()
{
    my $branch = gitBranch();
    chomp(my $override = `git config --bool branch.$branch.webKitBranchBuild`);
    return 1 if $override eq "true";
    return 0 if $override eq "false";

    unless (defined $isGitBranchBuild) {
        chomp(my $gitBranchBuild = `git config --bool core.webKitBranchBuild`);
        $isGitBranchBuild = $gitBranchBuild eq "true";
    }

    return $isGitBranchBuild;
}

sub isSVNDirectory($)
{
    my ($dir) = @_;

    return -d File::Spec->catdir($dir, ".svn");
}

sub isSVN()
{
    return $isSVN if defined $isSVN;

    $isSVN = isSVNDirectory(".");
    return $isSVN;
}

sub chdirReturningRelativePath($)
{
    my ($directory) = @_;
    my $previousDirectory = Cwd::getcwd();
    chdir $directory;
    my $newDirectory = Cwd::getcwd();
    return "." if $newDirectory eq $previousDirectory;
    return File::Spec->abs2rel($previousDirectory, $newDirectory);
}

sub determineGitRoot()
{
    chomp(my $gitDir = `git rev-parse --git-dir`);
    return dirname($gitDir);
}

sub determineSVNRoot()
{
    my $devNull = File::Spec->devnull();
    my $last = '';
    my $path = '.';
    my $parent = '..';
    my $repositoryUUID;
    while (1) {
        my $thisUUID;
        # Ignore error messages in case we've run past the root of the checkout.
        open INFO, "svn info '$path' 2> $devNull |" or die;
        while (<INFO>) {
            if (/^Repository UUID: (.+)/) {
                $thisUUID = $1;
                { local $/ = undef; <INFO>; }  # Consume the rest of the input.
            }
        }
        close INFO;

        # It's possible (e.g. for developers of some ports) to have a WebKit
        # checkout in a subdirectory of another checkout.  So abort if the
        # repository UUID suddenly changes.
        last if !$thisUUID;
        if (!$repositoryUUID) {
            $repositoryUUID = $thisUUID;
        }
        last if $thisUUID ne $repositoryUUID;

        $last = $path;
        $path = File::Spec->catdir($parent, $path);
    }

    return File::Spec->rel2abs($last);
}

sub determineVCSRoot()
{
    if (isGit()) {
        return determineGitRoot();
    }
    if (isSVN()) {
        return determineSVNRoot();
    }
    die "Unable to determine VCS root";
}

sub svnRevisionForDirectory($)
{
    my ($dir) = @_;
    my $revision;

    if (isSVNDirectory($dir)) {
        my $svnInfo = `LC_ALL=C svn info $dir | grep Revision:`;
        ($revision) = ($svnInfo =~ m/Revision: (\d+).*/g);
    } elsif (isGitDirectory($dir)) {
        my $gitLog = `cd $dir && LC_ALL=C git log --grep='git-svn-id: ' -n 1 | grep git-svn-id:`;
        ($revision) = ($gitLog =~ m/ +git-svn-id: .+@(\d+) /g);
    }
    die "Unable to determine current SVN revision in $dir" unless (defined $revision);
    return $revision;
}

sub pathRelativeToSVNRepositoryRootForPath($)
{
    my ($file) = @_;
    my $relativePath = File::Spec->abs2rel($file);

    my $svnInfo;
    if (isSVN()) {
        $svnInfo = `LC_ALL=C svn info $relativePath`;
    } elsif (isGit()) {
        $svnInfo = `LC_ALL=C git svn info $relativePath`;
    }

    $svnInfo =~ /.*^URL: (.*?)$/m;
    my $svnURL = $1;

    $svnInfo =~ /.*^Repository Root: (.*?)$/m;
    my $repositoryRoot = $1;

    $svnURL =~ s/$repositoryRoot\///;
    return $svnURL;
}


my $gitRoot;
sub makeFilePathRelative($)
{
    my ($path) = @_;
    return $path unless isGit();

    unless (defined $gitRoot) {
        chomp($gitRoot = `git rev-parse --show-cdup`);
    }
    return $gitRoot . $path;
}

1;