NRuby

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Searcher = function(data) {
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  this.data = data;
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  this.handlers = [];
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}
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Searcher.prototype = new function() {
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  // search is performed in chunks of 1000 for non-blocking user input
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  var CHUNK_SIZE = 1000;
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  // do not try to find more than 100 results
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  var MAX_RESULTS = 100;
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  var huid = 1;
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  var suid = 1;
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  var runs = 0;
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  this.find = function(query) {
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    var queries = splitQuery(query);
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    var regexps = buildRegexps(queries);
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    var highlighters = buildHilighters(queries);
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    var state = { from: 0, pass: 0, limit: MAX_RESULTS, n: suid++};
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    var _this = this;
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    this.currentSuid = state.n;
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    if (!query) return;
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    var run = function() {
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      // stop current search thread if new search started
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      if (state.n != _this.currentSuid) return;
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      var results =
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        performSearch(_this.data, regexps, queries, highlighters, state);
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      var hasMore = (state.limit > 0 && state.pass < 4);
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      triggerResults.call(_this, results, !hasMore);
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      if (hasMore) {
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        setTimeout(run, 2);
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      }
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      runs++;
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    };
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    runs = 0;
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    // start search thread
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    run();
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  }
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  /*  ----- Events ------  */
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  this.ready = function(fn) {
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    fn.huid = huid;
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    this.handlers.push(fn);
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  }
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  /*  ----- Utilities ------  */
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  function splitQuery(query) {
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    return query.split(/(\s+|::?|\(\)?)/).filter(function(string) {
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      return string.match(/\S/);
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    });
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  }
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  function buildRegexps(queries) {
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    return queries.map(function(query) {
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      return new RegExp(query.replace(/(.)/g, '([$1])([^$1]*?)'), 'i');
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    });
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  }
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  function buildHilighters(queries) {
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    return queries.map(function(query) {
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      return query.split('').map(function(l, i) {
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        return '\u0001$' + (i*2+1) + '\u0002$' + (i*2+2);
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      }).join('');
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    });
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  }
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  // function longMatchRegexp(index, longIndex, regexps) {
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  //     for (var i = regexps.length - 1; i >= 0; i--){
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  //         if (!index.match(regexps[i]) && !longIndex.match(regexps[i])) return false;
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  //     };
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  //     return true;
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  // }
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  /*  ----- Mathchers ------  */
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  /*
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   * This record matches if the index starts with queries[0] and the record
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   * matches all of the regexps
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   */
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  function matchPassBeginning(index, longIndex, queries, regexps) {
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    if (index.indexOf(queries[0]) != 0) return false;
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    for (var i=1, l = regexps.length; i < l; i++) {
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      if (!index.match(regexps[i]) && !longIndex.match(regexps[i]))
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        return false;
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    };
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    return true;
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  }
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  /*
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   * This record matches if the longIndex starts with queries[0] and the
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   * longIndex matches all of the regexps
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   */
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  function matchPassLongIndex(index, longIndex, queries, regexps) {
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    if (longIndex.indexOf(queries[0]) != 0) return false;
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    for (var i=1, l = regexps.length; i < l; i++) {
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      if (!longIndex.match(regexps[i]))
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        return false;
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    };
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    return true;
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  }
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  /*
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   * This record matches if the index contains queries[0] and the record
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   * matches all of the regexps
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   */
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  function matchPassContains(index, longIndex, queries, regexps) {
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    if (index.indexOf(queries[0]) == -1) return false;
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    for (var i=1, l = regexps.length; i < l; i++) {
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      if (!index.match(regexps[i]) && !longIndex.match(regexps[i]))
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        return false;
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    };
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    return true;
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  }
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  /*
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   * This record matches if regexps[0] matches the index and the record
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   * matches all of the regexps
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   */
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  function matchPassRegexp(index, longIndex, queries, regexps) {
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    if (!index.match(regexps[0])) return false;
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    for (var i=1, l = regexps.length; i < l; i++) {
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      if (!index.match(regexps[i]) && !longIndex.match(regexps[i]))
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        return false;
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    };
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    return true;
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  }
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  /*  ----- Highlighters ------  */
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  function highlightRegexp(info, queries, regexps, highlighters) {
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    var result = createResult(info);
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    for (var i=0, l = regexps.length; i < l; i++) {
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      result.title = result.title.replace(regexps[i], highlighters[i]);
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      result.namespace = result.namespace.replace(regexps[i], highlighters[i]);
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    };
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    return result;
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  }
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  function hltSubstring(string, pos, length) {
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    return string.substring(0, pos) + '\u0001' + string.substring(pos, pos + length) + '\u0002' + string.substring(pos + length);
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  }
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  function highlightQuery(info, queries, regexps, highlighters) {
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    var result = createResult(info);
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    var pos = 0;
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    var lcTitle = result.title.toLowerCase();
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    pos = lcTitle.indexOf(queries[0]);
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    if (pos != -1) {
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      result.title = hltSubstring(result.title, pos, queries[0].length);
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    }
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    result.namespace = result.namespace.replace(regexps[0], highlighters[0]);
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    for (var i=1, l = regexps.length; i < l; i++) {
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      result.title = result.title.replace(regexps[i], highlighters[i]);
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      result.namespace = result.namespace.replace(regexps[i], highlighters[i]);
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    };
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    return result;
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  }
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  function createResult(info) {
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    var result = {};
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    result.title = info[0];
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    result.namespace = info[1];
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    result.path = info[2];
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    result.params = info[3];
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    result.snippet = info[4];
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    result.badge = info[6];
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    return result;
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  }
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  /*  ----- Searching ------  */
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  function performSearch(data, regexps, queries, highlighters, state) {
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    var searchIndex = data.searchIndex;
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    var longSearchIndex = data.longSearchIndex;
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    var info = data.info;
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    var result = [];
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    var i = state.from;
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    var l = searchIndex.length;
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    var togo = CHUNK_SIZE;
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    var matchFunc, hltFunc;
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    while (state.pass < 4 && state.limit > 0 && togo > 0) {
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      if (state.pass == 0) {
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        matchFunc = matchPassBeginning;
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        hltFunc = highlightQuery;
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      } else if (state.pass == 1) {
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        matchFunc = matchPassLongIndex;
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        hltFunc = highlightQuery;
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      } else if (state.pass == 2) {
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        matchFunc = matchPassContains;
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        hltFunc = highlightQuery;
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      } else if (state.pass == 3) {
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        matchFunc = matchPassRegexp;
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        hltFunc = highlightRegexp;
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      }
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      for (; togo > 0 && i < l && state.limit > 0; i++, togo--) {
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        if (info[i].n == state.n) continue;
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        if (matchFunc(searchIndex[i], longSearchIndex[i], queries, regexps)) {
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          info[i].n = state.n;
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          result.push(hltFunc(info[i], queries, regexps, highlighters));
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          state.limit--;
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        }
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      };
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      if (searchIndex.length <= i) {
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        state.pass++;
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        i = state.from = 0;
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      } else {
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        state.from = i;
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      }
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    }
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    return result;
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  }
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  function triggerResults(results, isLast) {
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    this.handlers.forEach(function(fn) {
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      fn.call(this, results, isLast)
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    });
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  }
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}
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