78 lines
2.0 KiB
JavaScript
78 lines
2.0 KiB
JavaScript
'use strict';
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const { createLRU } = require('lru.min');
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const parserCache = createLRU({
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max: 15000,
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});
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// the fixed-size options head keeps JSON.stringify (cheap for a flat array,
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// and it normalizes exotic values the same way as before); the per-field part
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// is built by hand with length-prefixed strings, so no delimiter collision is
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// possible and no throwaway nested arrays are allocated per query
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function appendString(key, value) {
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if (value === undefined || value === null) {
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return `${key}u/`;
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}
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return `${key}${value.length}#${value}/`;
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}
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function keyFromFields(type, fields, options, config) {
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let key = JSON.stringify([
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type,
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typeof options.nestTables,
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options.nestTables,
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Boolean(options.rowsAsArray),
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Boolean(options.supportBigNumbers || config.supportBigNumbers),
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Boolean(options.bigNumberStrings || config.bigNumberStrings),
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typeof options.typeCast === 'boolean'
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? options.typeCast
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: typeof options.typeCast,
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options.timezone || config.timezone,
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Boolean(options.decimalNumbers),
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options.dateStrings,
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Boolean(config.jsonStrings),
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]);
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for (let i = 0; i < fields.length; ++i) {
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const field = fields[i];
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key = appendString(key, field.name);
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key += `${field.columnType}/${field.length}/`;
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key = appendString(key, field.schema);
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key = appendString(key, field.table);
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key += `${field.flags}/${field.characterSet}/`;
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key = appendString(key, field.extendedTypeName);
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key = appendString(key, field.extendedFormat);
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}
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return key;
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}
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function getParser(type, fields, options, config, compiler) {
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const key = keyFromFields(type, fields, options, config);
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let parser = parserCache.get(key);
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if (parser) {
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return parser;
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}
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parser = compiler(fields, options, config);
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parserCache.set(key, parser);
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return parser;
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}
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function setMaxCache(max) {
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parserCache.resize(max);
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}
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function clearCache() {
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parserCache.clear();
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}
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module.exports = {
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getParser: getParser,
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setMaxCache: setMaxCache,
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clearCache: clearCache,
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_keyFromFields: keyFromFields,
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};
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