time-to-botec

Benchmark sampling in different programming languages
Log | Files | Refs | README

_mergeData.js (3135B)

      1 var composeArgs = require('./_composeArgs'),
      2     composeArgsRight = require('./_composeArgsRight'),
      3     replaceHolders = require('./_replaceHolders');
      4 
      5 /** Used as the internal argument placeholder. */
      6 var PLACEHOLDER = '__lodash_placeholder__';
      7 
      8 /** Used to compose bitmasks for function metadata. */
      9 var WRAP_BIND_FLAG = 1,
     10     WRAP_BIND_KEY_FLAG = 2,
     11     WRAP_CURRY_BOUND_FLAG = 4,
     12     WRAP_CURRY_FLAG = 8,
     13     WRAP_ARY_FLAG = 128,
     14     WRAP_REARG_FLAG = 256;
     15 
     16 /* Built-in method references for those with the same name as other `lodash` methods. */
     17 var nativeMin = Math.min;
     18 
     19 /**
     20  * Merges the function metadata of `source` into `data`.
     21  *
     22  * Merging metadata reduces the number of wrappers used to invoke a function.
     23  * This is possible because methods like `_.bind`, `_.curry`, and `_.partial`
     24  * may be applied regardless of execution order. Methods like `_.ary` and
     25  * `_.rearg` modify function arguments, making the order in which they are
     26  * executed important, preventing the merging of metadata. However, we make
     27  * an exception for a safe combined case where curried functions have `_.ary`
     28  * and or `_.rearg` applied.
     29  *
     30  * @private
     31  * @param {Array} data The destination metadata.
     32  * @param {Array} source The source metadata.
     33  * @returns {Array} Returns `data`.
     34  */
     35 function mergeData(data, source) {
     36   var bitmask = data[1],
     37       srcBitmask = source[1],
     38       newBitmask = bitmask | srcBitmask,
     39       isCommon = newBitmask < (WRAP_BIND_FLAG | WRAP_BIND_KEY_FLAG | WRAP_ARY_FLAG);
     40 
     41   var isCombo =
     42     ((srcBitmask == WRAP_ARY_FLAG) && (bitmask == WRAP_CURRY_FLAG)) ||
     43     ((srcBitmask == WRAP_ARY_FLAG) && (bitmask == WRAP_REARG_FLAG) && (data[7].length <= source[8])) ||
     44     ((srcBitmask == (WRAP_ARY_FLAG | WRAP_REARG_FLAG)) && (source[7].length <= source[8]) && (bitmask == WRAP_CURRY_FLAG));
     45 
     46   // Exit early if metadata can't be merged.
     47   if (!(isCommon || isCombo)) {
     48     return data;
     49   }
     50   // Use source `thisArg` if available.
     51   if (srcBitmask & WRAP_BIND_FLAG) {
     52     data[2] = source[2];
     53     // Set when currying a bound function.
     54     newBitmask |= bitmask & WRAP_BIND_FLAG ? 0 : WRAP_CURRY_BOUND_FLAG;
     55   }
     56   // Compose partial arguments.
     57   var value = source[3];
     58   if (value) {
     59     var partials = data[3];
     60     data[3] = partials ? composeArgs(partials, value, source[4]) : value;
     61     data[4] = partials ? replaceHolders(data[3], PLACEHOLDER) : source[4];
     62   }
     63   // Compose partial right arguments.
     64   value = source[5];
     65   if (value) {
     66     partials = data[5];
     67     data[5] = partials ? composeArgsRight(partials, value, source[6]) : value;
     68     data[6] = partials ? replaceHolders(data[5], PLACEHOLDER) : source[6];
     69   }
     70   // Use source `argPos` if available.
     71   value = source[7];
     72   if (value) {
     73     data[7] = value;
     74   }
     75   // Use source `ary` if it's smaller.
     76   if (srcBitmask & WRAP_ARY_FLAG) {
     77     data[8] = data[8] == null ? source[8] : nativeMin(data[8], source[8]);
     78   }
     79   // Use source `arity` if one is not provided.
     80   if (data[9] == null) {
     81     data[9] = source[9];
     82   }
     83   // Use source `func` and merge bitmasks.
     84   data[0] = source[0];
     85   data[1] = newBitmask;
     86 
     87   return data;
     88 }
     89 
     90 module.exports = mergeData;