<?php

/*
* This file is part of Composer.
*
* (c) Nils Adermann <naderman@naderman.de>
* Jordi Boggiano <j.boggiano@seld.be>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/

namespace Composer;

use Composer\IO\IOInterface;
use Composer\Util\Filesystem;
use Composer\Util\Silencer;
use Symfony\Component\Finder\Finder;

/**
* Reads/writes to a filesystem cache
*
* @author Jordi Boggiano <j.boggiano@seld.be>
*/
class Cache
{
private static $cacheCollected = false;
private $io;
private $root;
private $enabled = true;
private $allowList;
private $filesystem;

/**
* @param IOInterface $io
* @param string $cacheDir location of the cache
* @param string $allowList List of characters that are allowed in path names (used in a regex character class)
* @param Filesystem $filesystem optional filesystem instance
*/
public function __construct(IOInterface $io, $cacheDir, $allowList = 'a-z0-9.', Filesystem $filesystem = null)
{
$this->io = $io;
$this->root = rtrim($cacheDir, '/\\') . '/';
$this->allowList = $allowList;
$this->filesystem = $filesystem ?: new Filesystem();

if (!self::isUsable($cacheDir)) {
$this->enabled = false;

return;
}

if (
(!is_dir($this->root) && !Silencer::call('mkdir', $this->root, 0777, true))
|| !is_writable($this->root)
) {
$this->io->writeError('<warning>Cannot create cache directory ' . $this->root . ', or directory is not writable. Proceeding without cache</warning>');
$this->enabled = false;
}
}

public static function isUsable($path)
{
return !preg_match('{(^|[\\\\/])(\$null|nul|NUL|/dev/null)([\\\\/]|$)}', $path);
}

public function isEnabled()
{
return $this->enabled;
}

public function getRoot()
{
return $this->root;
}

public function read($file)
{
if ($this->enabled) {
$file = preg_replace('{[^'.$this->allowList.']}i', '-', $file);
if (file_exists($this->root . $file)) {
$this->io->writeError('Reading '.$this->root . $file.' from cache', true, IOInterface::DEBUG);

return file_get_contents($this->root . $file);
}
}

return false;
}

public function write($file, $contents)
{
if ($this->enabled) {
$file = preg_replace('{[^'.$this->allowList.']}i', '-', $file);

$this->io->writeError('Writing '.$this->root . $file.' into cache', true, IOInterface::DEBUG);

try {
return file_put_contents($this->root . $file, $contents);
} catch (\ErrorException $e) {
$this->io->writeError('<warning>Failed to write into cache: '.$e->getMessage().'</warning>', true, IOInterface::DEBUG);
if (preg_match('{^file_put_contents\(\): Only ([0-9]+) of ([0-9]+) bytes written}', $e->getMessage(), $m)) {
// Remove partial file.
unlink($this->root . $file);

$message = sprintf(
'<warning>Writing %1$s into cache failed after %2$u of %3$u bytes written, only %4$u bytes of free space available</warning>',
$this->root . $file,
$m[1],
$m[2],
@disk_free_space($this->root . dirname($file))
);

$this->io->writeError($message);

return false;
}

throw $e;
}
}

return false;
}

/**
* Copy a file into the cache
*/
public function copyFrom($file, $source)
{
if ($this->enabled) {
$file = preg_replace('{[^'.$this->allowList.']}i', '-', $file);
$this->filesystem->ensureDirectoryExists(dirname($this->root . $file));

if (!file_exists($source)) {
$this->io->writeError('<error>'.$source.' does not exist, can not write into cache</error>');
} elseif ($this->io->isDebug()) {
$this->io->writeError('Writing '.$this->root . $file.' into cache from '.$source);
}

return copy($source, $this->root . $file);
}

return false;
}

/**
* Copy a file out of the cache
*/
public function copyTo($file, $target)
{
if ($this->enabled) {
$file = preg_replace('{[^'.$this->allowList.']}i', '-', $file);
if (file_exists($this->root . $file)) {
try {
touch($this->root . $file, filemtime($this->root . $file), time());
} catch (\ErrorException $e) {
// fallback in case the above failed due to incorrect ownership
// see https://github.com/composer/composer/issues/4070
Silencer::call('touch', $this->root . $file);
}

$this->io->writeError('Reading '.$this->root . $file.' from cache', true, IOInterface::DEBUG);

return copy($this->root . $file, $target);
}
}

return false;
}

public function gcIsNecessary()
{
return (!self::$cacheCollected && !mt_rand(0, 50));
}

public function remove($file)
{
if ($this->enabled) {
$file = preg_replace('{[^'.$this->allowList.']}i', '-', $file);
if (file_exists($this->root . $file)) {
return $this->filesystem->unlink($this->root . $file);
}
}

return false;
}

public function clear()
{
if ($this->enabled) {
$this->filesystem->emptyDirectory($this->root);
return true;
}

return false;
}

public function gc($ttl, $maxSize)
{
if ($this->enabled) {
$expire = new \DateTime();
$expire->modify('-'.$ttl.' seconds');

$finder = $this->getFinder()->date('until '.$expire->format('Y-m-d H:i:s'));
foreach ($finder as $file) {
$this->filesystem->unlink($file->getPathname());
}

$totalSize = $this->filesystem->size($this->root);
if ($totalSize > $maxSize) {
$iterator = $this->getFinder()->sortByAccessedTime()->getIterator();
while ($totalSize > $maxSize && $iterator->valid()) {
$filepath = $iterator->current()->getPathname();
$totalSize -= $this->filesystem->size($filepath);
$this->filesystem->unlink($filepath);
$iterator->next();
}
}

self::$cacheCollected = true;

return true;
}

return false;
}

public function sha1($file)
{
if ($this->enabled) {
$file = preg_replace('{[^'.$this->allowList.']}i', '-', $file);
if (file_exists($this->root . $file)) {
return sha1_file($this->root . $file);
}
}

return false;
}

public function sha256($file)
{
if ($this->enabled) {
$file = preg_replace('{[^'.$this->allowList.']}i', '-', $file);
if (file_exists($this->root . $file)) {
return hash_file('sha256', $this->root . $file);
}
}

return false;
}

protected function getFinder()
{
return Finder::create()->in($this->root)->files();
}
}