1<?php
2// This file is part of Moodle - http://moodle.org/
3//
4// Moodle is free software: you can redistribute it and/or modify
5// it under the terms of the GNU General Public License as published by
6// the Free Software Foundation, either version 3 of the License, or
7// (at your option) any later version.
8//
9// Moodle is distributed in the hope that it will be useful,
10// but WITHOUT ANY WARRANTY; without even the implied warranty of
11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12// GNU General Public License for more details.
13//
14// You should have received a copy of the GNU General Public License
15// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
16
17/**
18 * Moodle implementation of SCSS.
19 *
20 * @package    core
21 * @copyright  2016 Frédéric Massart
22 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
23 */
24
25defined('MOODLE_INTERNAL') || die();
26
27/**
28 * Moodle SCSS compiler class.
29 *
30 * @package    core
31 * @copyright  2016 Frédéric Massart
32 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
33 */
34class core_scss extends \ScssPhp\ScssPhp\Compiler {
35
36    /** @var string The path to the SCSS file. */
37    protected $scssfile;
38    /** @var array Bits of SCSS content to prepend. */
39    protected $scssprepend = array();
40    /** @var array Bits of SCSS content. */
41    protected $scsscontent = array();
42
43    /**
44     * Add variables.
45     *
46     * @param array $scss Associative array of variables and their values.
47     * @return void
48     */
49    public function add_variables(array $variables) {
50        $this->setVariables($variables);
51    }
52
53    /**
54     * Append raw SCSS to what's to compile.
55     *
56     * @param string $scss SCSS code.
57     * @return void
58     */
59    public function append_raw_scss($scss) {
60        $this->scsscontent[] = $scss;
61    }
62
63    /**
64     * Prepend raw SCSS to what's to compile.
65     *
66     * @param string $scss SCSS code.
67     * @return void
68     */
69    public function prepend_raw_scss($scss) {
70        $this->scssprepend[] = $scss;
71    }
72
73    /**
74     * Set the file to compile from.
75     *
76     * The purpose of this method is to provide a way to import the
77     * content of a file without messing with the import directories.
78     *
79     * @param string $filepath The path to the file.
80     * @return void
81     */
82    public function set_file($filepath) {
83        $this->scssfile = $filepath;
84        $this->setImportPaths([dirname($filepath)]);
85    }
86
87    /**
88     * Compiles to CSS.
89     *
90     * @return string
91     */
92    public function to_css() {
93        $content = implode(';', $this->scssprepend);
94        if (!empty($this->scssfile)) {
95            $content .= file_get_contents($this->scssfile);
96        }
97        $content .= implode(';', $this->scsscontent);
98        return $this->compile($content);
99    }
100
101    /**
102     * Compile scss.
103     *
104     * Overrides ScssPHP's implementation, using the SassC compiler if it is available.
105     *
106     * @param string $code SCSS to compile.
107     * @param string $path Path to SCSS to compile.
108     *
109     * @return string The compiled CSS.
110     */
111    public function compile($code, $path = null) {
112        global $CFG;
113
114        $pathtosassc = trim($CFG->pathtosassc ?? '');
115
116        if (!empty($pathtosassc) && is_executable($pathtosassc) && !is_dir($pathtosassc)) {
117            $process = proc_open(
118                $pathtosassc . ' -I' . implode(':', $this->importPaths) . ' -s',
119                [
120                    ['pipe', 'r'], // Set the process stdin pipe to read mode.
121                    ['pipe', 'w'], // Set the process stdout pipe to write mode.
122                    ['pipe', 'w'] // Set the process stderr pipe to write mode.
123                ],
124                $pipes // Pipes become available in $pipes (pass by reference).
125            );
126            if (is_resource($process)) {
127                fwrite($pipes[0], $code); // Write the raw scss to the sassc process stdin.
128                fclose($pipes[0]);
129
130                $stdout = stream_get_contents($pipes[1]);
131                $stderr = stream_get_contents($pipes[2]);
132
133                fclose($pipes[1]);
134                fclose($pipes[2]);
135
136                // The proc_close function returns the process exit status. Anything other than 0 is bad.
137                if (proc_close($process) !== 0) {
138                    throw new coding_exception($stderr);
139                }
140
141                // Compiled CSS code will be available from stdout.
142                return $stdout;
143            }
144        }
145
146        return parent::compile($code, $path);
147    }
148
149    /**
150     * Compile child; returns a value to halt execution
151     *
152     * @param array $child
153     * @param \ScssPhp\ScssPhp\Formatter\OutputBlock $out
154     *
155     * @return array|null
156     */
157    protected function compileChild($child, \ScssPhp\ScssPhp\Formatter\OutputBlock $out) {
158        switch($child[0]) {
159            case \ScssPhp\ScssPhp\Type::T_SCSSPHP_IMPORT_ONCE:
160            case \ScssPhp\ScssPhp\Type::T_IMPORT:
161                list(, $rawpath) = $child;
162                $rawpath = $this->reduce($rawpath);
163                $path = $this->compileStringContent($rawpath);
164                if ($path = $this->findImport($path)) {
165                    if ($this->is_valid_file($path)) {
166                        return parent::compileChild($child, $out);
167                    } else {
168                        // Sneaky stuff, don't let non scss file in.
169                        debugging("Can't import scss file - " . $path, DEBUG_DEVELOPER);
170                    }
171                }
172                break;
173            default:
174                return parent::compileChild($child, $out);
175        }
176    }
177
178    /**
179     * Is the given file valid for import ?
180     *
181     * @param $path
182     * @return bool
183     */
184    protected function is_valid_file($path) {
185        global $CFG;
186
187        $realpath = realpath($path);
188
189        // Additional theme directory.
190        $addthemedirectory = core_component::get_plugin_types()['theme'];
191        $addrealroot = realpath($addthemedirectory);
192
193        // Original theme directory.
194        $themedirectory = $CFG->dirroot . "/theme";
195        $realroot = realpath($themedirectory);
196
197        // File should end in .scss and must be in sites theme directory, else ignore it.
198        $pathvalid = $realpath !== false;
199        $pathvalid = $pathvalid && (substr($path, -5) === '.scss');
200        $pathvalid = $pathvalid && (strpos($realpath, $realroot) === 0 || strpos($realpath, $addrealroot) === 0);
201        return $pathvalid;
202    }
203}
204