<?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\Autoload;

/**
 * ClassLoader implements a PSR-0, PSR-4 and classmap class loader.
 *
 *     $loader = new \Composer\Autoload\ClassLoader();
 *
 *     // register classes with namespaces
 *     $loader->add('Symfony\Component', __DIR__.'/component');
 *     $loader->add('Symfony',           __DIR__.'/framework');
 *
 *     // activate the autoloader
 *     $loader->register();
 *
 *     // to enable searching the include path (eg. for PEAR packages)
 *     $loader->setUseIncludePath(true);
 *
 * In this example, if you try to use a class in the Symfony\Component
 * namespace or one of its children (Symfony\Component\Console for instance),
 * the autoloader will first look for the class under the component/
 * directory, and it will then fallback to the framework/ directory if not
 * found before giving up.
 *
 * This class is loosely based on the Symfony UniversalClassLoader.
 *
 * @author Fabien Potencier <fabien@symfony.com>
 * @author Jordi Boggiano <j.boggiano@seld.be>
 * @see    http://www.php-fig.org/psr/psr-0/
 * @see    http://www.php-fig.org/psr/psr-4/
 */
class ClassLoader
{
	// PSR-4
	private $prefixLengthsPsr4 = [];
	private $prefixDirsPsr4    = [];
	private $fallbackDirsPsr4  = [];

	// PSR-0
	private $prefixesPsr0     = [];
	private $fallbackDirsPsr0 = [];

	private $useIncludePath        = false;
	private $classMap              = [];
	private $classMapAuthoritative = false;
	private $missingClasses        = [];
	private $apcuPrefix;

	public function getPrefixes()
	{
		if ( ! empty($this->prefixesPsr0))
		{
			return call_user_func_array('array_merge', $this->prefixesPsr0);
		}

		return [];
	}

	public function getPrefixesPsr4()
	{
		return $this->prefixDirsPsr4;
	}

	public function getFallbackDirs()
	{
		return $this->fallbackDirsPsr0;
	}

	public function getFallbackDirsPsr4()
	{
		return $this->fallbackDirsPsr4;
	}

	public function getClassMap()
	{
		return $this->classMap;
	}

	/**
	 * @param array $classMap Class to filename map
	 */
	public function addClassMap(array $classMap)
	{
		if ($this->classMap)
		{
			$this->classMap = array_merge($this->classMap, $classMap);
		}
		else
		{
			$this->classMap = $classMap;
		}
	}

	/**
	 * Registers a set of PSR-0 directories for a given prefix, either
	 * appending or prepending to the ones previously set for this prefix.
	 *
	 * @param string       $prefix  The prefix
	 * @param array|string $paths   The PSR-0 root directories
	 * @param bool         $prepend Whether to prepend the directories
	 */
	public function add($prefix, $paths, $prepend = false)
	{
		if ( ! $prefix)
		{
			if ($prepend)
			{
				$this->fallbackDirsPsr0 = array_merge(
					(array) $paths,
					$this->fallbackDirsPsr0
				);
			}
			else
			{
				$this->fallbackDirsPsr0 = array_merge(
					$this->fallbackDirsPsr0,
					(array) $paths
				);
			}

			return;
		}

		$first = $prefix[0];
		if ( ! isset($this->prefixesPsr0[$first][$prefix]))
		{
			$this->prefixesPsr0[$first][$prefix] = (array) $paths;

			return;
		}
		if ($prepend)
		{
			$this->prefixesPsr0[$first][$prefix] = array_merge(
				(array) $paths,
				$this->prefixesPsr0[$first][$prefix]
			);
		}
		else
		{
			$this->prefixesPsr0[$first][$prefix] = array_merge(
				$this->prefixesPsr0[$first][$prefix],
				(array) $paths
			);
		}
	}

	/**
	 * Registers a set of PSR-4 directories for a given namespace, either
	 * appending or prepending to the ones previously set for this namespace.
	 *
	 * @param string       $prefix  The prefix/namespace, with trailing '\\'
	 * @param array|string $paths   The PSR-4 base directories
	 * @param bool         $prepend Whether to prepend the directories
	 *
	 * @throws \InvalidArgumentException
	 */
	public function addPsr4($prefix, $paths, $prepend = false)
	{
		if ( ! $prefix)
		{
			// Register directories for the root namespace.
			if ($prepend)
			{
				$this->fallbackDirsPsr4 = array_merge(
					(array) $paths,
					$this->fallbackDirsPsr4
				);
			}
			else
			{
				$this->fallbackDirsPsr4 = array_merge(
					$this->fallbackDirsPsr4,
					(array) $paths
				);
			}
		}
		elseif ( ! isset($this->prefixDirsPsr4[$prefix]))
		{
			// Register directories for a new namespace.
			$length = strlen($prefix);
			if ('\\' !== $prefix[$length - 1])
			{
				throw new \InvalidArgumentException("A non-empty PSR-4 prefix must end with a namespace separator.");
			}
			$this->prefixLengthsPsr4[$prefix[0]][$prefix] = $length;
			$this->prefixDirsPsr4[$prefix]                = (array) $paths;
		}
		elseif ($prepend)
		{
			// Prepend directories for an already registered namespace.
			$this->prefixDirsPsr4[$prefix] = array_merge(
				(array) $paths,
				$this->prefixDirsPsr4[$prefix]
			);
		}
		else
		{
			// Append directories for an already registered namespace.
			$this->prefixDirsPsr4[$prefix] = array_merge(
				$this->prefixDirsPsr4[$prefix],
				(array) $paths
			);
		}
	}

	/**
	 * Registers a set of PSR-0 directories for a given prefix,
	 * replacing any others previously set for this prefix.
	 *
	 * @param string       $prefix The prefix
	 * @param array|string $paths  The PSR-0 base directories
	 */
	public function set($prefix, $paths)
	{
		if ( ! $prefix)
		{
			$this->fallbackDirsPsr0 = (array) $paths;
		}
		else
		{
			$this->prefixesPsr0[$prefix[0]][$prefix] = (array) $paths;
		}
	}

	/**
	 * Registers a set of PSR-4 directories for a given namespace,
	 * replacing any others previously set for this namespace.
	 *
	 * @param string       $prefix The prefix/namespace, with trailing '\\'
	 * @param array|string $paths  The PSR-4 base directories
	 *
	 * @throws \InvalidArgumentException
	 */
	public function setPsr4($prefix, $paths)
	{
		if ( ! $prefix)
		{
			$this->fallbackDirsPsr4 = (array) $paths;
		}
		else
		{
			$length = strlen($prefix);
			if ('\\' !== $prefix[$length - 1])
			{
				throw new \InvalidArgumentException("A non-empty PSR-4 prefix must end with a namespace separator.");
			}
			$this->prefixLengthsPsr4[$prefix[0]][$prefix] = $length;
			$this->prefixDirsPsr4[$prefix]                = (array) $paths;
		}
	}

	/**
	 * Turns on searching the include path for class files.
	 *
	 * @param bool $useIncludePath
	 */
	public function setUseIncludePath($useIncludePath)
	{
		$this->useIncludePath = $useIncludePath;
	}

	/**
	 * Can be used to check if the autoloader uses the include path to check
	 * for classes.
	 *
	 * @return bool
	 */
	public function getUseIncludePath()
	{
		return $this->useIncludePath;
	}

	/**
	 * Turns off searching the prefix and fallback directories for classes
	 * that have not been registered with the class map.
	 *
	 * @param bool $classMapAuthoritative
	 */
	public function setClassMapAuthoritative($classMapAuthoritative)
	{
		$this->classMapAuthoritative = $classMapAuthoritative;
	}

	/**
	 * Should class lookup fail if not found in the current class map?
	 *
	 * @return bool
	 */
	public function isClassMapAuthoritative()
	{
		return $this->classMapAuthoritative;
	}

	/**
	 * APCu prefix to use to cache found/not-found classes, if the extension is enabled.
	 *
	 * @param string|null $apcuPrefix
	 */
	public function setApcuPrefix($apcuPrefix)
	{
		$this->apcuPrefix = function_exists('apcu_fetch') && ini_get('apc.enabled') ? $apcuPrefix : null;
	}

	/**
	 * The APCu prefix in use, or null if APCu caching is not enabled.
	 *
	 * @return string|null
	 */
	public function getApcuPrefix()
	{
		return $this->apcuPrefix;
	}

	/**
	 * Registers this instance as an autoloader.
	 *
	 * @param bool $prepend Whether to prepend the autoloader or not
	 */
	public function register($prepend = false)
	{
		spl_autoload_register([$this, 'loadClass'], true, $prepend);
	}

	/**
	 * Unregisters this instance as an autoloader.
	 */
	public function unregister()
	{
		spl_autoload_unregister([$this, 'loadClass']);
	}

	/**
	 * Loads the given class or interface.
	 *
	 * @param string $class The name of the class
	 *
	 * @return bool|null True if loaded, null otherwise
	 */
	public function loadClass($class)
	{
		if ($file = $this->findFile($class))
		{
			includeFile($file);

			return true;
		}
	}

	/**
	 * Finds the path to the file where the class is defined.
	 *
	 * @param string $class The name of the class
	 *
	 * @return string|false The path if found, false otherwise
	 */
	public function findFile($class)
	{
		// class map lookup
		if (isset($this->classMap[$class]))
		{
			return $this->classMap[$class];
		}
		if ($this->classMapAuthoritative || isset($this->missingClasses[$class]))
		{
			return false;
		}
		if (null !== $this->apcuPrefix)
		{
			$file = apcu_fetch($this->apcuPrefix . $class, $hit);
			if ($hit)
			{
				return $file;
			}
		}

		$file = $this->findFileWithExtension($class, '.php');

		// Search for Hack files if we are running on HHVM
		if (false === $file && defined('HHVM_VERSION'))
		{
			$file = $this->findFileWithExtension($class, '.hh');
		}

		if (null !== $this->apcuPrefix)
		{
			apcu_add($this->apcuPrefix . $class, $file);
		}

		if (false === $file)
		{
			// Remember that this class does not exist.
			$this->missingClasses[$class] = true;
		}

		return $file;
	}

	private function findFileWithExtension($class, $ext)
	{
		// PSR-4 lookup
		$logicalPathPsr4 = strtr($class, '\\', DIRECTORY_SEPARATOR) . $ext;

		$first = $class[0];
		if (isset($this->prefixLengthsPsr4[$first]))
		{
			foreach ($this->prefixLengthsPsr4[$first] as $prefix => $length)
			{
				if (0 === strpos($class, $prefix))
				{
					foreach ($this->prefixDirsPsr4[$prefix] as $dir)
					{
						if (file_exists($file = $dir . DIRECTORY_SEPARATOR . substr($logicalPathPsr4, $length)))
						{
							return $file;
						}
					}
				}
			}
		}

		// PSR-4 fallback dirs
		foreach ($this->fallbackDirsPsr4 as $dir)
		{
			if (file_exists($file = $dir . DIRECTORY_SEPARATOR . $logicalPathPsr4))
			{
				return $file;
			}
		}

		// PSR-0 lookup
		if (false !== $pos = strrpos($class, '\\'))
		{
			// namespaced class name
			$logicalPathPsr0 = substr($logicalPathPsr4, 0, $pos + 1)
				. strtr(substr($logicalPathPsr4, $pos + 1), '_', DIRECTORY_SEPARATOR);
		}
		else
		{
			// PEAR-like class name
			$logicalPathPsr0 = strtr($class, '_', DIRECTORY_SEPARATOR) . $ext;
		}

		if (isset($this->prefixesPsr0[$first]))
		{
			foreach ($this->prefixesPsr0[$first] as $prefix => $dirs)
			{
				if (0 === strpos($class, $prefix))
				{
					foreach ($dirs as $dir)
					{
						if (file_exists($file = $dir . DIRECTORY_SEPARATOR . $logicalPathPsr0))
						{
							return $file;
						}
					}
				}
			}
		}

		// PSR-0 fallback dirs
		foreach ($this->fallbackDirsPsr0 as $dir)
		{
			if (file_exists($file = $dir . DIRECTORY_SEPARATOR . $logicalPathPsr0))
			{
				return $file;
			}
		}

		// PSR-0 include paths.
		if ($this->useIncludePath && $file = stream_resolve_include_path($logicalPathPsr0))
		{
			return $file;
		}

		return false;
	}
}

/**
 * Scope isolated include.
 *
 * Prevents access to $this/self from included files.
 */
function includeFile($file)
{
	include $file;
}
