Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

namespace core\output;

use Mustache_Tokenizer;

/**

 * Load template source strings.

 *

 * @copyright  2018 Ryan Wyllie <ryan@moodle.com>

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 * @package core

 */

class mustache_template_source_loader {

    /** @var $gettemplatesource Callback function to load the template source from full name */

    private $gettemplatesource = null;

    /**

     * Constructor that takes a callback to allow the calling code to specify how to retrieve

     * the source for a template name.

     *

     * If no callback is provided then default to the load from disk implementation.

     *

     * @param callable|null $gettemplatesource Callback to load template source by template name

     */

    public function __construct(?callable $gettemplatesource = null) {

        if ($gettemplatesource) {

            // The calling code has specified a function for retrieving the template source

            // code by name and theme.

            $this->gettemplatesource = $gettemplatesource;

        } else {

            // By default we will pull the template from disk.

            $this->gettemplatesource = function ($component, $name, $themename) {

                $fulltemplatename = $component . '/' . $name;

                $filename = mustache_template_finder::get_template_filepath($fulltemplatename, $themename);

                return file_get_contents($filename);

            };

        }

    }

    /**

     * Remove comments from mustache template.

     *

     * @param string $templatestr

     * @return string

     */

    protected function strip_template_comments($templatestr): string {

        return preg_replace('/(?={{!)(.*)(}})/sU', '', $templatestr);

    }

    /**

     * Load the template source from the component and template name.

     *

     * @param string $component The moodle component (e.g. core_message)

     * @param string $name The template name (e.g. message_drawer)

     * @param string $themename The theme to load the template for (e.g. boost)

     * @param bool $includecomments If the comments should be stripped from the source before returning

     * @return string The template source

     */

    public function load(

        string $component,

        string $name,

        string $themename,

        bool $includecomments = false

    ): string {

        global $CFG;

        // Get the template source from the callback.

        $source = ($this->gettemplatesource)($component, $name, $themename);

        // Remove comments from template.

        if (!$includecomments) {

            $source = $this->strip_template_comments($source);

        }

        if (!empty($CFG->debugtemplateinfo)) {

            return "<!-- template(JS): $name -->" . $source . "<!-- /template(JS): $name -->";

        }

        return $source;

    }

    /**

     * Load a template and some of the dependencies that will be needed in order to render

     * the template.

     *

     * The current implementation will return all of the templates and all of the strings in

     * each of those templates (excluding string substitutions).

     *

     * The return format is an array indexed with the dependency type (e.g. templates / strings) then

     * the component (e.g. core_message), and then the id (e.g. message_drawer).

     *

     * For example:

     * * We have 3 templates in core named foo, bar, and baz.

     * * foo includes bar and bar includes baz.

     * * foo uses the string 'home' from core

     * * baz uses the string 'help' from core

     *

     * If we load the template foo this function would return:

     * [

     *      'templates' => [

     *          'core' => [

     *              'foo' => '... template source ...',

     *              'bar' => '... template source ...',

     *              'baz' => '... template source ...',

     *          ]

     *      ],

     *      'strings' => [

     *          'core' => [

     *              'home' => 'Home',

     *              'help' => 'Help'

     *          ]

     *      ]

     * ]

     *

     * @param string $templatecomponent The moodle component (e.g. core_message)

     * @param string $templatename The template name (e.g. message_drawer)

     * @param string $themename The theme to load the template for (e.g. boost)

     * @param bool $includecomments If the comments should be stripped from the source before returning

     * @param array $seentemplates List of templates already processed / to be skipped.

     * @param array $seenstrings List of strings already processed / to be skipped.

     * @param string|null $lang moodle translation language, null means use current.

     * @return array

     */

    public function load_with_dependencies(

        string $templatecomponent,

        string $templatename,

        string $themename,

        bool $includecomments = false,

        array $seentemplates = [],

        array $seenstrings = [],

        ?string $lang = null

    ): array {

        // Initialise the return values.

        $templates = [];

        $strings = [];

        $templatecomponent = trim($templatecomponent);

        $templatename = trim($templatename);

        // Get the requested template source.

        $templatesource = $this->load($templatecomponent, $templatename, $themename, $includecomments);

        // This is a helper function to save a value in one of the result arrays (either $templates or $strings).

        $save = function (array $results, array $seenlist, string $component, string $id, $value) use ($lang) {

            if (!isset($results[$component])) {

                // If the results list doesn't already contain this component then initialise it.

                $results[$component] = [];

            }

            // Save the value.

            $results[$component][$id] = $value;

            // Record that this item has been processed.

            array_push($seenlist, "$component/$id");

            // Return the updated results and seen list.

            return [$results, $seenlist];

        };

        // This is a helper function for processing a dependency. Does stuff like ignore duplicate processing,

        // common result formatting etc.

        $handler = function (array $dependency, array $ignorelist, callable $processcallback) use ($lang) {

            foreach ($dependency as $component => $ids) {

                foreach ($ids as $id) {

                    $dependencyid = "$component/$id";

                    if (array_search($dependencyid, $ignorelist) === false) {

                        $processcallback($component, $id);

                        // Add this to our ignore list now that we've processed it so that we don't

                        // process it again.

                        array_push($ignorelist, $dependencyid);

                    }

                }

            }

            return $ignorelist;

        };

        // Save this template as the first result in the $templates result array.

        [$templates, $seentemplates] = $save($templates, $seentemplates, $templatecomponent, $templatename, $templatesource);

        // Check the template for any dependencies that need to be loaded.

        $dependencies = $this->scan_template_source_for_dependencies($templatesource);

        // Load all of the lang strings that this template requires and add them to the

        // returned values.

        $seenstrings = $handler(

            $dependencies['strings'],

            $seenstrings,

            // Include $strings and $seenstrings by reference so that their values can be updated

            // outside of this anonymous function.

            function ($component, $id) use ($save, &$strings, &$seenstrings, $lang) {

                $string = get_string_manager()->get_string($id, $component, null, $lang);

                // Save the string in the $strings results array.

                [$strings, $seenstrings] = $save($strings, $seenstrings, $component, $id, $string);

            }

        );

        // Load any child templates that we've found in this template and add them to

        // the return list of dependencies.

        $seentemplates = $handler(

            $dependencies['templates'],

            $seentemplates,

            // Include $strings, $seenstrings, $templates, and $seentemplates by reference so that their values can be updated

            // outside of this anonymous function.

            function (

                $component,

                $id

            ) use (

                $themename,

                $includecomments,

                &$seentemplates,

                &$seenstrings,

                &$templates,

                &$strings,

                $save,

                $lang

            ) {

                // We haven't seen this template yet so load it and it's dependencies.

                $subdependencies = $this->load_with_dependencies(

                    $component,

                    $id,

                    $themename,

                    $includecomments,

                    $seentemplates,

                    $seenstrings,

                    $lang

                );

                foreach ($subdependencies['templates'] as $component => $ids) {

                    foreach ($ids as $id => $value) {

                        // Include the child themes in our results.

                        [$templates, $seentemplates] = $save($templates, $seentemplates, $component, $id, $value);

                    }

                };

                foreach ($subdependencies['strings'] as $component => $ids) {

                    foreach ($ids as $id => $value) {

                        // Include any strings that the child templates need in our results.

                        [$strings, $seenstrings] = $save($strings, $seenstrings, $component, $id, $value);

                    }

                }

            }

        );

        return [

            'templates' => $templates,

            'strings' => $strings,

        ];

    }

    /**

     * Scan over a template source string and return a list of dependencies it requires.

     * At the moment the list will only include other templates and strings.

     *

     * The return format is an array indexed with the dependency type (e.g. templates / strings) then

     * the component (e.g. core_message) with it's value being an array of the items required

     * in that component.

     *

     * For example:

     * If we have a template foo that includes 2 templates, bar and baz, and also 2 strings

     * 'home' and 'help' from the core component then the return value would look like:

     *

     * [

     *      'templates' => [

     *          'core' => ['foo', 'bar', 'baz']

     *      ],

     *      'strings' => [

     *          'core' => ['home', 'help']

     *      ]

     * ]

     *

     * @param string $source The template source

     * @return array

     */

    protected function scan_template_source_for_dependencies(string $source): array {

        $tokenizer = new Mustache_Tokenizer();

        $tokens = $tokenizer->scan($source);

        $templates = [];

        $strings = [];

        $addtodependencies = function ($dependencies, $component, $id) {

            $id = trim($id);

            $component = trim($component);

            if (!isset($dependencies[$component])) {

                // Initialise the component if we haven't seen it before.

                $dependencies[$component] = [];

            }

            // Add this id to the list of dependencies.

            array_push($dependencies[$component], $id);

            return $dependencies;

        };

        foreach ($tokens as $index => $token) {

            $type = $token['type'];

            $name = isset($token['name']) ? $token['name'] : null;

            if ($name) {

                switch ($type) {

                    case Mustache_Tokenizer::T_PARTIAL:

                        [$component, $id] = explode('/', $name, 2);

                        $templates = $addtodependencies($templates, $component, $id);

                        break;

                    case Mustache_Tokenizer::T_PARENT:

                        [$component, $id] = explode('/', $name, 2);

                        $templates = $addtodependencies($templates, $component, $id);

                        break;

                    case Mustache_Tokenizer::T_SECTION:

                        if ($name == 'str') {

                            [$id, $component] = $this->get_string_identifiers($tokens, $index);

                            if ($id) {

                                $strings = $addtodependencies($strings, $component, $id);

                            }

                        }

                        break;

                }

            }

        }

        return [

            'templates' => $templates,

            'strings' => $strings,

        ];

    }

    /**

     * Gets the identifier and component of the string.

     *

     * The string could be defined on one, or multiple lines.

     *

     * @param array $tokens The templates token.

     * @param int $start The index of the start of the string token.

     * @return array A list of the string identifier and component.

     */

    protected function get_string_identifiers(array $tokens, int $start): array {

        $current = $start + 1;

        $parts = [];

        // Get the contents of the string tag.

        while ($tokens[$current]['type'] !== Mustache_Tokenizer::T_END_SECTION) {

            if (!isset($tokens[$current]['value']) || empty(trim($tokens[$current]['value']))) {

                // An empty line, so we should ignore it.

                $current++;

                continue;

            }

            // We need to remove any spaces before and after the string.

            $nospaces = trim($tokens[$current]['value']);

            // We need to remove any trailing commas so that the explode will not add an

            // empty entry where two paramters are on multiple lines.

            $clean = rtrim($nospaces, ',');

            // We separate the parts of a string with commas.

            $subparts = explode(',', $clean);

            // Store the parts.

            $parts = array_merge($parts, $subparts);

            $current++;

        }

        // The first text should be the first part of a str tag.

        $id = isset($parts[0]) ? trim($parts[0]) : null;

        // Default to 'core' for the component, if not specified.

        $component = isset($parts[1]) ? trim($parts[1]) : 'core';

        return [$id, $component];

    }

}