104 lines
2.9 KiB
JavaScript
104 lines
2.9 KiB
JavaScript
var hasOwnProperty = Object.prototype.hasOwnProperty;
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var keywords = Object.create(null);
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var properties = Object.create(null);
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var HYPHENMINUS = 45; // '-'.charCodeAt()
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function isCustomProperty(str, offset) {
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offset = offset || 0;
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return str.length - offset >= 2 &&
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str.charCodeAt(offset) === HYPHENMINUS &&
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str.charCodeAt(offset + 1) === HYPHENMINUS;
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}
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function getVendorPrefix(str, offset) {
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offset = offset || 0;
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// verdor prefix should be at least 3 chars length
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if (str.length - offset >= 3) {
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// vendor prefix starts with hyper minus following non-hyper minus
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if (str.charCodeAt(offset) === HYPHENMINUS &&
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str.charCodeAt(offset + 1) !== HYPHENMINUS) {
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// vendor prefix should contain a hyper minus at the ending
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var secondDashIndex = str.indexOf('-', offset + 2);
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if (secondDashIndex !== -1) {
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return str.substring(offset, secondDashIndex + 1);
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}
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}
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}
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return '';
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}
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function getKeywordDescriptor(keyword) {
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if (hasOwnProperty.call(keywords, keyword)) {
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return keywords[keyword];
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}
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var name = keyword.toLowerCase();
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if (hasOwnProperty.call(keywords, name)) {
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return keywords[keyword] = keywords[name];
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}
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var custom = isCustomProperty(name, 0);
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var vendor = !custom ? getVendorPrefix(name, 0) : '';
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return keywords[keyword] = Object.freeze({
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basename: name.substr(vendor.length),
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name: name,
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vendor: vendor,
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prefix: vendor,
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custom: custom
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});
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}
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function getPropertyDescriptor(property) {
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if (hasOwnProperty.call(properties, property)) {
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return properties[property];
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}
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var name = property;
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var hack = property[0];
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if (hack === '/') {
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hack = property[1] === '/' ? '//' : '/';
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} else if (hack !== '_' &&
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hack !== '*' &&
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hack !== '$' &&
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hack !== '#' &&
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hack !== '+' &&
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hack !== '&') {
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hack = '';
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}
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var custom = isCustomProperty(name, hack.length);
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// re-use result when possible (the same as for lower case)
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if (!custom) {
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name = name.toLowerCase();
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if (hasOwnProperty.call(properties, name)) {
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return properties[property] = properties[name];
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}
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}
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var vendor = !custom ? getVendorPrefix(name, hack.length) : '';
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var prefix = name.substr(0, hack.length + vendor.length);
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return properties[property] = Object.freeze({
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basename: name.substr(prefix.length),
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name: name.substr(hack.length),
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hack: hack,
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vendor: vendor,
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prefix: prefix,
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custom: custom
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});
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}
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module.exports = {
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keyword: getKeywordDescriptor,
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property: getPropertyDescriptor,
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isCustomProperty: isCustomProperty,
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vendorPrefix: getVendorPrefix
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};
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