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<?php

namespace TYPO3\PharStreamWrapper\Resolver;

/*

 * This file is part of the TYPO3 project.

 *

 * It is free software; you can redistribute it and/or modify it under the terms

 * of the MIT License (MIT). For the full copyright and license information,

 * please read the LICENSE file that was distributed with this source code.

 *

 * The TYPO3 project - inspiring people to share!

 */

use TYPO3\PharStreamWrapper\Helper;

use TYPO3\PharStreamWrapper\Manager;

use TYPO3\PharStreamWrapper\Phar\Reader;

use TYPO3\PharStreamWrapper\Resolvable;

class PharInvocationResolver implements Resolvable

{

    const RESOLVE_REALPATH = 1;

    const RESOLVE_ALIAS = 2;

    const ASSERT_INTERNAL_INVOCATION = 32;

    /**

     * @var string[]

     */

    private $invocationFunctionNames = array(

        'include',

        'include_once',

        'require',

        'require_once'

    );

    /**

     * Contains resolved base names in order to reduce file IO.

     *

     * @var string[]

     */

    private $baseNames = array();

    /**

     * Resolves PharInvocation value object (baseName and optional alias).

     *

     * Phar aliases are intended to be used only inside Phar archives, however

     * PharStreamWrapper needs this information exposed outside of Phar as well

     * It is possible that same alias is used for different $baseName values.

     * That's why PharInvocationCollection behaves like a stack when resolving

     * base-name for a given alias. On the other hand it is not possible that

     * one $baseName is referring to multiple aliases.

     * @see https://secure.php.net/manual/en/phar.setalias.php

     * @see https://secure.php.net/manual/en/phar.mapphar.php

     *

     * @param string $path

     * @param int|null $flags

     * @return null|PharInvocation

     */

    public function resolve($path, $flags = null)

    {

        $hasPharPrefix = Helper::hasPharPrefix($path);

        if ($flags === null) {

            $flags = static::RESOLVE_REALPATH | static::RESOLVE_ALIAS | static::ASSERT_INTERNAL_INVOCATION;

        }

        if ($hasPharPrefix && $flags & static::RESOLVE_ALIAS) {

            $invocation = $this->findByAlias($path);

            if ($invocation !== null) {

                return $invocation;

            }

        }

        $baseName = $this->resolveBaseName($path, $flags);

        if ($baseName === null) {

            return null;

        }

        if ($flags & static::RESOLVE_REALPATH) {

            $baseName = $this->baseNames[$baseName];

        }

        return $this->retrieveInvocation($baseName, $flags);

    }

    /**

     * Retrieves PharInvocation, either existing in collection or created on demand

     * with resolving a potential alias name used in the according Phar archive.

     *

     * @param string $baseName

     * @param int $flags

     * @return PharInvocation

     */

    private function retrieveInvocation($baseName, $flags)

    {

        $invocation = $this->findByBaseName($baseName);

        if ($invocation !== null) {

            return $invocation;

        }

        if ($flags & static::RESOLVE_ALIAS) {

            $reader = new Reader($baseName);

            $alias = $reader->resolveContainer()->getAlias();

        } else {

            $alias = '';

        }

        // add unconfirmed(!) new invocation to collection

        $invocation = new PharInvocation($baseName, $alias);

        Manager::instance()->getCollection()->collect($invocation);

        return $invocation;

    }

    /**

     * @param string $path

     * @param int $flags

     * @return null|string

     */

    private function resolveBaseName($path, $flags)

    {

        $baseName = $this->findInBaseNames($path);

        if ($baseName !== null) {

            return $baseName;

        }

        $baseName = Helper::determineBaseFile($path);

        if ($baseName !== null) {

            $this->addBaseName($baseName);

            return $baseName;

        }

        $possibleAlias = $this->resolvePossibleAlias($path);

        if (!($flags & static::RESOLVE_ALIAS) || $possibleAlias === null) {

            return null;

        }

        $trace = debug_backtrace();

        foreach ($trace as $item) {

            if (!isset($item['function']) || !isset($item['args'][0])

                || !in_array($item['function'], $this->invocationFunctionNames, true)) {

                continue;

            }

            $currentPath = $item['args'][0];

            if (Helper::hasPharPrefix($currentPath)) {

                continue;

            }

            $currentBaseName = Helper::determineBaseFile($currentPath);

            if ($currentBaseName === null) {

                continue;

            }

            // ensure the possible alias name (how we have been called initially) matches

            // the resolved alias name that was retrieved by the current possible base name

            $reader = new Reader($currentBaseName);

            $currentAlias = $reader->resolveContainer()->getAlias();

            if ($currentAlias !== $possibleAlias) {

                continue;

            }

            $this->addBaseName($currentBaseName);

            return $currentBaseName;

        }

        return null;

    }

    /**

     * @param string $path

     * @return null|string

     */

    private function resolvePossibleAlias($path)

    {

        $normalizedPath = Helper::normalizePath($path);

        return strstr($normalizedPath, '/', true) ?: null;

    }

    /**

     * @param string $baseName

     * @return null|PharInvocation

     */

    private function findByBaseName($baseName)

    {

        return Manager::instance()->getCollection()->findByCallback(

            function (PharInvocation $candidate) use ($baseName) {

                return $candidate->getBaseName() === $baseName;

            },

            true

        );

    }

    /**

     * @param string $path

     * @return null|string

     */

    private function findInBaseNames($path)

    {

        // return directly if the resolved base name was submitted

        if (in_array($path, $this->baseNames, true)) {

            return $path;

        }

        $parts = explode('/', Helper::normalizePath($path));

        while (count($parts)) {

            $currentPath = implode('/', $parts);

            if (isset($this->baseNames[$currentPath])) {

                return $currentPath;

            }

            array_pop($parts);

        }

        return null;

    }

    /**

     * @param string $baseName

     */

    private function addBaseName($baseName)

    {

        if (isset($this->baseNames[$baseName])) {

            return;

        }

        $this->baseNames[$baseName] = realpath($baseName);

    }

    /**

     * Finds confirmed(!) invocations by alias.

     *

     * @param string $path

     * @return null|PharInvocation

     * @see \TYPO3\PharStreamWrapper\PharStreamWrapper::collectInvocation()

     */

    private function findByAlias($path)

    {

        $possibleAlias = $this->resolvePossibleAlias($path);

        if ($possibleAlias === null) {

            return null;

        }

        return Manager::instance()->getCollection()->findByCallback(

            function (PharInvocation $candidate) use ($possibleAlias) {

                return $candidate->isConfirmed() && $candidate->getAlias() === $possibleAlias;

            },

            true

        );

    }

}