Backport mozilla#308 onto 0.6.1

Author: benthemonkey

dist/source-map.debug.js

@@ -786,6 +786,43 @@ return /******/ (function(modules) { // webpackBootstrap
 	}
 	exports.urlGenerate = urlGenerate;
 
+	var MAX_CACHED_INPUTS = 32;
+
+	/**
+	 * Takes some function `f(input) -> result` and returns a memoized version of
+	 * `f`.
+	 *
+	 * We keep at most `MAX_CACHED_INPUTS` memoized results of `f` alive. The
+	 * memoization is a dumb-simple, linear least-recently-used cache.
+	 */
+	function lruMemoize(f) {
+	  var cache = [];
+
+	  return function(input) {
+	    for (var i = 0; i < cache.length; i++) {
+	      if (cache[i].input === input) {
+	        var temp = cache[0];
+	        cache[0] = cache[i];
+	        cache[i] = temp;
+	        return cache[0].result;
+	      }
+	    }
+
+	    var result = f(input);
+
+	    cache.unshift({
+	      input,
+	      result,
+	    });
+
+	    if (cache.length > MAX_CACHED_INPUTS) {
+	      cache.pop();
+	    }
+
+	    return result;
+	  };
+	}
+
 	/**
 	 * Normalizes a path, or the path portion of a URL:
 	 *
@@ -797,7 +834,7 @@ return /******/ (function(modules) { // webpackBootstrap
 	 *
 	 * @param aPath The path or url to normalize.
 	 */
-	function normalize(aPath) {
+	var normalize = lruMemoize(function normalize(aPath) {
 	  var path = aPath;
 	  var url = urlParse(aPath);
 	  if (url) {
@@ -807,8 +844,25 @@ return /******/ (function(modules) { // webpackBootstrap
 	    path = url.path;
 	  }
 	  var isAbsolute = exports.isAbsolute(path);
+	  // Split the path into parts between `/` characters. This is much faster than
+	  // using `.split(/\/+/g)`.
+	  var parts = [];
+	  var start = 0;
+	  var i = 0;
+	  while (true) {
+	    start = i;
+	    i = path.indexOf("/", start);
+	    if (i === -1) {
+	      parts.push(path.slice(start));
+	      break;
+	    } else {
+	      parts.push(path.slice(start, i));
+	      while (i < path.length && path[i] === "/") {
+	        i++;
+	      }
+	    }
+	  }
 
-	  var parts = path.split(/\/+/);
 	  for (var part, up = 0, i = parts.length - 1; i >= 0; i--) {
 	    part = parts[i];
 	    if (part === '.') {
@@ -839,7 +893,7 @@ return /******/ (function(modules) { // webpackBootstrap
 	    return urlGenerate(url);
 	  }
 	  return path;
-	}
+	});
 	exports.normalize = normalize;
 
 	/**