piston-export

#!/usr/bin/env php
<?php

if(!isset($_SERVER['argv'][2])) {
    echo "Usage: {$_SERVER['argv'][0]} (piston dir) (dest repository) (dest branch)
    
For example:

cd ~/Sites/yourproject
piston-export sapphire ~/Sites/gitdev/sapphire newchanges

If you have checked an external into your git project using piston, and then made changes to it, you
need a way of getting those changes back.

This script will export all of those changes to a new git branch of a working copy or if the option
`--patches-only` is passed, then a list of patch files will be produced.  Where possible, it leaves 
the hard work to git.\n";
    exit(1);
}

$pistonDir = $_SERVER['argv'][1];
$pistonDirFull = realpath($pistonDir);
$destRepos = realpath($_SERVER['argv'][2]);
$destBranch = isset($_SERVER['argv'][3]) ? $_SERVER['argv'][3] : 'master';

$args = array(
	'patches-only' => false
);

// check flags
foreach($_SERVER['argv'] as $arg) {
	if(substr($arg, 0, 2) == "--") {
		$key = substr($arg, 2);
		$value = (strpos($arg, "=") !== false) ? substr($arg, strpos($arg, "=")) : true;
		
		if(isset($args[$key])) $args[$key] = $value;
		else {
			echo "unknow flag $arg";
			exit(1);
		}
	}
}


if(!file_exists("$pistonDir/.piston.yml")) {
    echo "$pistonDir not a piston external ($pistonDir/.piston.yml not found)\n";
    exit(2);
}

if(!file_exists("$destRepos/.git") && !$args['patches-only']) {
    echo "$destRepos not a piston external ($destRepos/.git not found)\n";
    exit(3);
}

if(file_exists("$destRepos/.git/rebase-apply")) {
	echo "You should call 'git --git-dir=$destRepos/.git am --abort' on your dest repository first\n";
	exit(4);
}

require_once('Spyc.php');



$parser = new Spyc;
$config = $parser->load("$pistonDirFull/.piston.yml");

if(isset($config['exported_to'])) {
	$logFilter = $config['exported_to'] . "..HEAD";
} else {
	$logFilter = "";
}

$allHashes = explode("\n", trim(`git log --pretty="%H" $logFilter $pistonDir`));
$hashesToIgnore = explode("\n", trim(`git log --pretty="%H" $logFilter $pistonDir/.piston.yml`));

if($allHashes == array("")) $allHashes = array();
if($hashesToIgnore == array("")) $hashesToIgnore = array();

if(!$allHashes) {
	if(isset($config['exported_to'])) {
		echo "There weren't any more patches to apply since {$config['exported_to']}\n";
	} else {
		echo "There weren't any patches to apply\n";
	}
	exit(0);
}
	
$patchDirBase = "$destRepos/piston-export-" . date('Ymd');
$patchDir = $patchDirBase;
$suffix = 1;
while(file_exists($patchDir)) {
	$suffix++;
	$patchDir = "$patchDirBase-$suffix";
}
mkdir($patchDir);

$hashesToInclude = array_diff($allHashes, $hashesToIgnore);
$hashesToInclude = array_reverse($hashesToInclude);


foreach($hashesToInclude as $i => $hash) {
	$patchFile = str_pad($i, 5, 0, STR_PAD_LEFT) . '.patch';
	echo "Creating patch for $hash -> $patchDir/$patchFile\n";
	`git format-patch --relative=$pistonDir --stdout $hash~..$hash > $patchDir/$patchFile`;
}

if(!$args['patches-only']) {
	// Update config without the full destructive powers of Spyc
	$yaml = file_get_contents("$pistonDirFull/.piston.yml");
	$newExportedTo = trim(`git rev-parse HEAD`);
	$replacedSuccessfully = false;
	$yaml = preg_replace('/exported_to: ([a-zA-Z0-9]+)/', "exported_to: $newExportedTo", $yaml, -1, $replacedSuccessfully);
	
	if(!$replacedSuccessfully) {
		$yaml .= "\nexported_to: $newExportedTo";
	}
	
	file_put_contents("$pistonDirFull/.piston.yml", $yaml);

	// Apply the patches
	chdir($destRepos);
	
	if(!trim(`git branch | grep $destBranch`)) {
		echo "Creating dest branch '$destBranch'...\n";
		`git checkout -b $destBranch`;
	} else {
		echo "Checking out dest branch '$destBranch'...\n";
		`git checkout $destBranch`;
	}

	echo "Applying patches (git am --reject --ignore-whitespace --whitespace=nowarn -p 1 $patchDir/*)...\n";
	passthru("git am --reject --ignore-whitespace --whitespace=nowarn -p 1 $patchDir/*");
}