<?php

/**
 * This class is adapted from code coming from Zend Framework.
 *
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license   http://framework.zend.com/license/new-bsd New BSD License
 */

class Twig_Test_EscapingTest extends PHPUnit_Framework_TestCase
{
    /**
     * All character encodings supported by htmlspecialchars()
     */
    protected $htmlSpecialChars = array(
        '\''    => '&#039;',
        '"'     => '&quot;',
        '<'     => '&lt;',
        '>'     => '&gt;',
        '&'     => '&amp;'
    );

    protected $htmlAttrSpecialChars = array(
        '\''    => '&#x27;',
        /* Characters beyond ASCII value 255 to unicode escape */
        'Ā'     => '&#x0100;',
        /* Immune chars excluded */
        ','     => ',',
        '.'     => '.',
        '-'     => '-',
        '_'     => '_',
        /* Basic alnums excluded */
        'a'     => 'a',
        'A'     => 'A',
        'z'     => 'z',
        'Z'     => 'Z',
        '0'     => '0',
        '9'     => '9',
        /* Basic control characters and null */
        "\r"    => '&#x0D;',
        "\n"    => '&#x0A;',
        "\t"    => '&#x09;',
        "\0"    => '&#xFFFD;', // should use Unicode replacement char
        /* Encode chars as named entities where possible */
        '<'     => '&lt;',
        '>'     => '&gt;',
        '&'     => '&amp;',
        '"'     => '&quot;',
        /* Encode spaces for quoteless attribute protection */
        ' '     => '&#x20;',
    );

    protected $jsSpecialChars = array(
        /* HTML special chars - escape without exception to hex */
        '<'     => '\\x3C',
        '>'     => '\\x3E',
        '\''    => '\\x27',
        '"'     => '\\x22',
        '&'     => '\\x26',
        /* Characters beyond ASCII value 255 to unicode escape */
        'Ā'     => '\\u0100',
        /* Immune chars excluded */
        ','     => ',',
        '.'     => '.',
        '_'     => '_',
        /* Basic alnums excluded */
        'a'     => 'a',
        'A'     => 'A',
        'z'     => 'z',
        'Z'     => 'Z',
        '0'     => '0',
        '9'     => '9',
        /* Basic control characters and null */
        "\r"    => '\\x0D',
        "\n"    => '\\x0A',
        "\t"    => '\\x09',
        "\0"    => '\\x00',
        /* Encode spaces for quoteless attribute protection */
        ' '     => '\\x20',
    );

    protected $urlSpecialChars = array(
        /* HTML special chars - escape without exception to percent encoding */
        '<'     => '%3C',
        '>'     => '%3E',
        '\''    => '%27',
        '"'     => '%22',
        '&'     => '%26',
        /* Characters beyond ASCII value 255 to hex sequence */
        'Ā'     => '%C4%80',
        /* Punctuation and unreserved check */
        ','     => '%2C',
        '.'     => '.',
        '_'     => '_',
        '-'     => '-',
        ':'     => '%3A',
        ';'     => '%3B',
        '!'     => '%21',
        /* Basic alnums excluded */
        'a'     => 'a',
        'A'     => 'A',
        'z'     => 'z',
        'Z'     => 'Z',
        '0'     => '0',
        '9'     => '9',
        /* Basic control characters and null */
        "\r"    => '%0D',
        "\n"    => '%0A',
        "\t"    => '%09',
        "\0"    => '%00',
        /* PHP quirks from the past */
        ' '     => '%20',
        '~'     => '~',
        '+'     => '%2B',
    );

    protected $cssSpecialChars = array(
        /* HTML special chars - escape without exception to hex */
        '<'     => '\\3C ',
        '>'     => '\\3E ',
        '\''    => '\\27 ',
        '"'     => '\\22 ',
        '&'     => '\\26 ',
        /* Characters beyond ASCII value 255 to unicode escape */
        'Ā'     => '\\100 ',
        /* Immune chars excluded */
        ','     => '\\2C ',
        '.'     => '\\2E ',
        '_'     => '\\5F ',
        /* Basic alnums excluded */
        'a'     => 'a',
        'A'     => 'A',
        'z'     => 'z',
        'Z'     => 'Z',
        '0'     => '0',
        '9'     => '9',
        /* Basic control characters and null */
        "\r"    => '\\D ',
        "\n"    => '\\A ',
        "\t"    => '\\9 ',
        "\0"    => '\\0 ',
        /* Encode spaces for quoteless attribute protection */
        ' '     => '\\20 ',
    );

    protected $env;

    public function setUp()
    {
        $this->env = new Twig_Environment();
    }

    public function testHtmlEscapingConvertsSpecialChars()
    {
        foreach ($this->htmlSpecialChars as $key => $value) {
            $this->assertEquals($value, twig_escape_filter($this->env, $key, 'html'), 'Failed to escape: '.$key);
        }
    }

    public function testHtmlAttributeEscapingConvertsSpecialChars()
    {
        foreach ($this->htmlAttrSpecialChars as $key => $value) {
            $this->assertEquals($value, twig_escape_filter($this->env, $key, 'html_attr'), 'Failed to escape: '.$key);
        }
    }

    public function testJavascriptEscapingConvertsSpecialChars()
    {
        foreach ($this->jsSpecialChars as $key => $value) {
            $this->assertEquals($value, twig_escape_filter($this->env, $key, 'js'), 'Failed to escape: '.$key);
        }
    }

    public function testJavascriptEscapingReturnsStringIfZeroLength()
    {
        $this->assertEquals('', twig_escape_filter($this->env, '', 'js'));
    }

    public function testJavascriptEscapingReturnsStringIfContainsOnlyDigits()
    {
        $this->assertEquals('123', twig_escape_filter($this->env, '123', 'js'));
    }

    public function testCssEscapingConvertsSpecialChars()
    {
        foreach ($this->cssSpecialChars as $key => $value) {
            $this->assertEquals($value, twig_escape_filter($this->env, $key, 'css'), 'Failed to escape: '.$key);
        }
    }

    public function testCssEscapingReturnsStringIfZeroLength()
    {
        $this->assertEquals('', twig_escape_filter($this->env, '', 'css'));
    }

    public function testCssEscapingReturnsStringIfContainsOnlyDigits()
    {
        $this->assertEquals('123', twig_escape_filter($this->env, '123', 'css'));
    }

    public function testUrlEscapingConvertsSpecialChars()
    {
        foreach ($this->urlSpecialChars as $key => $value) {
            $this->assertEquals($value, twig_escape_filter($this->env, $key, 'url'), 'Failed to escape: '.$key);
        }
    }

    /**
     * Range tests to confirm escaped range of characters is within OWASP recommendation
     */

    /**
     * Only testing the first few 2 ranges on this prot. function as that's all these
     * other range tests require
     */
    public function testUnicodeCodepointConversionToUtf8()
    {
        $expected = " ~ޙ";
        $codepoints = array(0x20, 0x7e, 0x799);
        $result = '';
        foreach ($codepoints as $value) {
            $result .= $this->codepointToUtf8($value);
        }
        $this->assertEquals($expected, $result);
    }

    /**
     * Convert a Unicode Codepoint to a literal UTF-8 character.
     *
     * @param int Unicode codepoint in hex notation
     * @return string UTF-8 literal string
     */
    protected function codepointToUtf8($codepoint)
    {
        if ($codepoint < 0x80) {
            return chr($codepoint);
        }
        if ($codepoint < 0x800) {
            return chr($codepoint >> 6 & 0x3f | 0xc0)
                . chr($codepoint & 0x3f | 0x80);
        }
        if ($codepoint < 0x10000) {
            return chr($codepoint >> 12 & 0x0f | 0xe0)
                . chr($codepoint >> 6 & 0x3f | 0x80)
                . chr($codepoint & 0x3f | 0x80);
        }
        if ($codepoint < 0x110000) {
            return chr($codepoint >> 18 & 0x07 | 0xf0)
                . chr($codepoint >> 12 & 0x3f | 0x80)
                . chr($codepoint >> 6 & 0x3f | 0x80)
                . chr($codepoint & 0x3f | 0x80);
        }
        throw new Exception('Codepoint requested outside of Unicode range');
    }

    public function testJavascriptEscapingEscapesOwaspRecommendedRanges()
    {
        $immune = array(',', '.', '_'); // Exceptions to escaping ranges
        for ($chr=0; $chr < 0xFF; $chr++) {
            if ($chr >= 0x30 && $chr <= 0x39
            || $chr >= 0x41 && $chr <= 0x5A
            || $chr >= 0x61 && $chr <= 0x7A) {
                $literal = $this->codepointToUtf8($chr);
                $this->assertEquals($literal, twig_escape_filter($this->env, $literal, 'js'));
            } else {
                $literal = $this->codepointToUtf8($chr);
                if (in_array($literal, $immune)) {
                    $this->assertEquals($literal, twig_escape_filter($this->env, $literal, 'js'));
                } else {
                    $this->assertNotEquals(
                        $literal,
                        twig_escape_filter($this->env, $literal, 'js'),
                        "$literal should be escaped!");
                }
            }
        }
    }

    public function testHtmlAttributeEscapingEscapesOwaspRecommendedRanges()
    {
        $immune = array(',', '.', '-', '_'); // Exceptions to escaping ranges
        for ($chr=0; $chr < 0xFF; $chr++) {
            if ($chr >= 0x30 && $chr <= 0x39
            || $chr >= 0x41 && $chr <= 0x5A
            || $chr >= 0x61 && $chr <= 0x7A) {
                $literal = $this->codepointToUtf8($chr);
                $this->assertEquals($literal, twig_escape_filter($this->env, $literal, 'html_attr'));
            } else {
                $literal = $this->codepointToUtf8($chr);
                if (in_array($literal, $immune)) {
                    $this->assertEquals($literal, twig_escape_filter($this->env, $literal, 'html_attr'));
                } else {
                    $this->assertNotEquals(
                        $literal,
                        twig_escape_filter($this->env, $literal, 'html_attr'),
                        "$literal should be escaped!");
                }
            }
        }
    }

    public function testCssEscapingEscapesOwaspRecommendedRanges()
    {
        $immune = array(); // CSS has no exceptions to escaping ranges
        for ($chr=0; $chr < 0xFF; $chr++) {
            if ($chr >= 0x30 && $chr <= 0x39
            || $chr >= 0x41 && $chr <= 0x5A
            || $chr >= 0x61 && $chr <= 0x7A) {
                $literal = $this->codepointToUtf8($chr);
                $this->assertEquals($literal, twig_escape_filter($this->env, $literal, 'css'));
            } else {
                $literal = $this->codepointToUtf8($chr);
                $this->assertNotEquals(
                    $literal,
                    twig_escape_filter($this->env, $literal, 'css'),
                    "$literal should be escaped!");
            }
        }
    }
}
