#!/usr/bin/perl
# Copyright (c) 2007-2014, Anthony Minessale II
# All rights reserved.
# 
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 
# Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 
# 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.
# 
# Neither the name of the original author; nor the names of any contributors
# may be used to endorse or promote products derived from this software
# without specific prior written permission.
# 
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT OWNER
# OR 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.
# 
# Contributors: 
# 
# hashfinder - Find origin of a particular line of code
#

my $file = shift;
my $regex = shift;
my $alt_file = shift;
my $delim = "  ";

$file and $regex or die "missing params.  Syntax: <file> <regex>";

sub doit($$) {
  my $rev = shift;
  my $pattern = shift;
  my $loops = shift || 0;
  my $linematch = 0;

  if ($pattern =~ /^\~(.*)/) {
	  $pattern = $1;
  } else {
	  $pattern = quotemeta $pattern;
  }

  if ($pattern =~ /^(\d+)$/) {
    $linematch = 1;
  }

 retry:

  open GIT, "git blame -n $file $rev 2>&1|";

  my $mc = 0;
  my @matches = ();

  while (<GIT>) {
    my $matched = 0;

	if (/fatal:/) {
		if ($alt_file) {
			$file = $alt_file;
			$alt_file = undef;
			goto retry;
		}
	}

    if ($linematch) {
      $matched = (/^\S+\s+$pattern\s+/);
    } else {
      $matched = (/$pattern/);
    }

    if ($matched) {
      s/[\r\n]//g;
      push @matches, $_;
      $mc++;
    }
  }

  close(GIT);

  if ($mc > 5) {
    print $delim x $loops;
    print "$mc matches; Maybe more specific?\n";
    
    foreach (@matches) {
      print "$_\n";
    }

	return;

  }

  my $x = 0;

  foreach (@matches) {
    my ($hash, $lno, $author, $line);
    my $done = 0;

    if (/\//) {
      ($hash, $lno, $author, $line) = /(\S+)\s+\S+\s+(\S+)\s+(\([^\)]+\))\s*(.*)/;
      $done = 1;
    } else {
		die $_;
      ($hash, $lno, $author, $line) = /(\S+)\s+(\S+)\s+(\([^\)]+\))\s*(.*)/;
    }

    if ($hash) {
		$line =~ s/^\s+//g;

		print "\n";
		print $delim x $loops;
		my $msg = `git log -1 --pretty=format:%B $hash`;
		print "[$hash] [$lno] [$author] [$line]\n";
		print $delim x $loops;
		print ":: $msg\n";
		doit("$hash" . "^", $line, $loops+1);
		print "\n";
    }

    last if $done;

  }
}

doit(undef, $regex);


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