CasperSecurity
'use strict';
const generate = require('regjsgen').generate;
const parse = require('regjsparser').parse;
const regenerate = require('regenerate');
const unicodeMatchProperty = require('unicode-match-property-ecmascript');
const unicodeMatchPropertyValue = require('unicode-match-property-value-ecmascript');
const iuMappings = require('./data/iu-mappings.js');
const ESCAPE_SETS = require('./data/character-class-escape-sets.js');
// Prepare a Regenerate set containing all code points, used for negative
// character classes (if any).
const UNICODE_SET = regenerate().addRange(0x0, 0x10FFFF);
// Without the `u` flag, the range stops at 0xFFFF.
// https://mths.be/es6#sec-pattern-semantics
const BMP_SET = regenerate().addRange(0x0, 0xFFFF);
// Prepare a Regenerate set containing all code points that are supposed to be
// matched by `/./u`. https://mths.be/es6#sec-atom
const DOT_SET_UNICODE = UNICODE_SET.clone() // all Unicode code points
.remove(
// minus `LineTerminator`s (https://mths.be/es6#sec-line-terminators):
0x000A, // Line Feed <LF>
0x000D, // Carriage Return <CR>
0x2028, // Line Separator <LS>
0x2029 // Paragraph Separator <PS>
);
const getCharacterClassEscapeSet = (character, unicode, ignoreCase) => {
if (unicode) {
if (ignoreCase) {
return ESCAPE_SETS.UNICODE_IGNORE_CASE.get(character);
}
return ESCAPE_SETS.UNICODE.get(character);
}
return ESCAPE_SETS.REGULAR.get(character);
};
const getUnicodeDotSet = (dotAll) => {
return dotAll ? UNICODE_SET : DOT_SET_UNICODE;
};
const getUnicodePropertyValueSet = (property, value) => {
const path = value ?
`${ property }/${ value }` :
`Binary_Property/${ property }`;
try {
return require(`regenerate-unicode-properties/${ path }.js`);
} catch (exception) {
throw new Error(
`Failed to recognize value \`${ value }\` for property ` +
`\`${ property }\`.`
);
}
};
const handleLoneUnicodePropertyNameOrValue = (value) => {
// It could be a `General_Category` value or a binary property.
// Note: `unicodeMatchPropertyValue` throws on invalid values.
try {
const property = 'General_Category';
const category = unicodeMatchPropertyValue(property, value);
return getUnicodePropertyValueSet(property, category);
} catch (exception) {}
// It’s not a `General_Category` value, so check if it’s a binary
// property. Note: `unicodeMatchProperty` throws on invalid properties.
const property = unicodeMatchProperty(value);
return getUnicodePropertyValueSet(property);
};
const getUnicodePropertyEscapeSet = (value, isNegative) => {
const parts = value.split('=');
const firstPart = parts[0];
let set;
if (parts.length == 1) {
set = handleLoneUnicodePropertyNameOrValue(firstPart);
} else {
// The pattern consists of two parts, i.e. `Property=Value`.
const property = unicodeMatchProperty(firstPart);
const value = unicodeMatchPropertyValue(property, parts[1]);
set = getUnicodePropertyValueSet(property, value);
}
if (isNegative) {
return UNICODE_SET.clone().remove(set);
}
return set.clone();
};
// Given a range of code points, add any case-folded code points in that range
// to a set.
regenerate.prototype.iuAddRange = function(min, max) {
const $this = this;
do {
const folded = caseFold(min);
if (folded) {
$this.add(folded);
}
} while (++min <= max);
return $this;
};
const update = (item, pattern) => {
let tree = parse(pattern, config.useUnicodeFlag ? 'u' : '');
switch (tree.type) {
case 'characterClass':
case 'group':
case 'value':
// No wrapping needed.
break;
default:
// Wrap the pattern in a non-capturing group.
tree = wrap(tree, pattern);
}
Object.assign(item, tree);
};
const wrap = (tree, pattern) => {
// Wrap the pattern in a non-capturing group.
return {
'type': 'group',
'behavior': 'ignore',
'body': [tree],
'raw': `(?:${ pattern })`
};
};
const caseFold = (codePoint) => {
return iuMappings.get(codePoint) || false;
};
const processCharacterClass = (characterClassItem, regenerateOptions) => {
const set = regenerate();
for (const item of characterClassItem.body) {
switch (item.type) {
case 'value':
set.add(item.codePoint);
if (config.ignoreCase && config.unicode && !config.useUnicodeFlag) {
const folded = caseFold(item.codePoint);
if (folded) {
set.add(folded);
}
}
break;
case 'characterClassRange':
const min = item.min.codePoint;
const max = item.max.codePoint;
set.addRange(min, max);
if (config.ignoreCase && config.unicode && !config.useUnicodeFlag) {
set.iuAddRange(min, max);
}
break;
case 'characterClassEscape':
set.add(getCharacterClassEscapeSet(
item.value,
config.unicode,
config.ignoreCase
));
break;
case 'unicodePropertyEscape':
set.add(getUnicodePropertyEscapeSet(item.value, item.negative));
break;
// The `default` clause is only here as a safeguard; it should never be
// reached. Code coverage tools should ignore it.
/* istanbul ignore next */
default:
throw new Error(`Unknown term type: ${ item.type }`);
}
}
if (characterClassItem.negative) {
update(characterClassItem, `(?!${set.toString(regenerateOptions)})[\\s\\S]`)
} else {
update(characterClassItem, set.toString(regenerateOptions));
}
return characterClassItem;
};
const updateNamedReference = (item, index) => {
delete item.name;
item.matchIndex = index;
};
const assertNoUnmatchedReferences = (groups) => {
const unmatchedReferencesNames = Object.keys(groups.unmatchedReferences);
if (unmatchedReferencesNames.length > 0) {
throw new Error(`Unknown group names: ${unmatchedReferencesNames}`);
}
};
const processTerm = (item, regenerateOptions, groups) => {
switch (item.type) {
case 'dot':
if (config.useDotAllFlag) {
break;
} else if (config.unicode) {
update(
item,
getUnicodeDotSet(config.dotAll).toString(regenerateOptions)
);
} else if (config.dotAll) {
// TODO: consider changing this at the regenerate level.
update(item, '[\\s\\S]');
}
break;
case 'characterClass':
item = processCharacterClass(item, regenerateOptions);
break;
case 'unicodePropertyEscape':
if (config.unicodePropertyEscape) {
update(
item,
getUnicodePropertyEscapeSet(item.value, item.negative)
.toString(regenerateOptions)
);
}
break;
case 'characterClassEscape':
update(
item,
getCharacterClassEscapeSet(
item.value,
config.unicode,
config.ignoreCase
).toString(regenerateOptions)
);
break;
case 'group':
if (item.behavior == 'normal') {
groups.lastIndex++;
}
if (item.name && config.namedGroup) {
const name = item.name.value;
if (groups.names[name]) {
throw new Error(
`Multiple groups with the same name (${ name }) are not allowed.`
);
}
const index = groups.lastIndex;
delete item.name;
groups.names[name] = index;
if (groups.onNamedGroup) {
groups.onNamedGroup.call(null, name, index);
}
if (groups.unmatchedReferences[name]) {
groups.unmatchedReferences[name].forEach(reference => {
updateNamedReference(reference, index);
});
delete groups.unmatchedReferences[name];
}
}
/* falls through */
case 'alternative':
case 'disjunction':
case 'quantifier':
item.body = item.body.map(term => {
return processTerm(term, regenerateOptions, groups);
});
break;
case 'value':
const codePoint = item.codePoint;
const set = regenerate(codePoint);
if (config.ignoreCase && config.unicode && !config.useUnicodeFlag) {
const folded = caseFold(codePoint);
if (folded) {
set.add(folded);
}
}
update(item, set.toString(regenerateOptions));
break;
case 'reference':
if (item.name) {
const name = item.name.value;
const index = groups.names[name];
if (index) {
updateNamedReference(item, index);
break;
}
if (!groups.unmatchedReferences[name]) {
groups.unmatchedReferences[name] = [];
}
// Keep track of references used before the corresponding group.
groups.unmatchedReferences[name].push(item);
}
break;
case 'anchor':
case 'empty':
case 'group':
// Nothing to do here.
break;
// The `default` clause is only here as a safeguard; it should never be
// reached. Code coverage tools should ignore it.
/* istanbul ignore next */
default:
throw new Error(`Unknown term type: ${ item.type }`);
}
return item;
};
const config = {
'ignoreCase': false,
'unicode': false,
'dotAll': false,
'useDotAllFlag': false,
'useUnicodeFlag': false,
'unicodePropertyEscape': false,
'namedGroup': false
};
const rewritePattern = (pattern, flags, options) => {
config.unicode = flags && flags.includes('u');
const regjsparserFeatures = {
'unicodePropertyEscape': config.unicode,
'namedGroups': true,
'lookbehind': options && options.lookbehind
};
config.ignoreCase = flags && flags.includes('i');
const supportDotAllFlag = options && options.dotAllFlag;
config.dotAll = supportDotAllFlag && flags && flags.includes('s');
config.namedGroup = options && options.namedGroup;
config.useDotAllFlag = options && options.useDotAllFlag;
config.useUnicodeFlag = options && options.useUnicodeFlag;
config.unicodePropertyEscape = options && options.unicodePropertyEscape;
if (supportDotAllFlag && config.useDotAllFlag) {
throw new Error('`useDotAllFlag` and `dotAllFlag` cannot both be true!');
}
const regenerateOptions = {
'hasUnicodeFlag': config.useUnicodeFlag,
'bmpOnly': !config.unicode
};
const groups = {
'onNamedGroup': options && options.onNamedGroup,
'lastIndex': 0,
'names': Object.create(null), // { [name]: index }
'unmatchedReferences': Object.create(null) // { [name]: Array<reference> }
};
const tree = parse(pattern, flags, regjsparserFeatures);
// Note: `processTerm` mutates `tree` and `groups`.
processTerm(tree, regenerateOptions, groups);
assertNoUnmatchedReferences(groups);
return generate(tree);
};
module.exports = rewritePattern;