Revert "Minifying renamer for classes, methods and instance variables."

lib/compiler/implementation/js_backend/minify_namer.dart

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-/**
- * Assigns JavaScript identifiers to Dart variables, class-names and members.
- */
-class MinifyNamer extends Namer {
-  MinifyNamer(Compiler compiler) : super(compiler);
-
-  String get ISOLATE => 'I';
-  String get ISOLATE_PROPERTIES => 'p';
-  bool get shouldMinify => true;
-
-  const ALPHABET_CHARACTERS = 52;  // a-zA-Z.
-  const ALPHANUMERIC_CHARACTERS = 62;  // a-zA-Z0-9.
-
-  String getFreshName(String proposedName, Set<String> usedNames) {
-    var freshName = _getUnusedName(proposedName, usedNames);
-    usedNames.add(freshName);
-    return freshName;
-  }
-
-  // This gets a minified name based on a hash of the proposed name.  This
-  // is slightly less efficient than just getting the next name in a series,
-  // but it means that small changes in the input program will give smallish
-  // changes in the output, which can be useful for diffing etc.
-  String _getUnusedName(String proposedName, Set<String> usedNames) {
-    // Try single-character names with characters that occur in the
-    // input.
-    for (int i = 0; i < proposedName.length; i++) {
-      String candidate = proposedName[i];
-      int code = candidate.charCodeAt(0);
-      if (code < $A) continue;
-      if (code > $z) continue;
-      if (code > $Z && code < $a) continue;
-      if (!usedNames.contains(candidate)) return candidate;
-    }
-
-    int hash = _calculateHash(proposedName);
-    // Avoid very small hashes that won't try many names.
-    hash = hash < 1000 ? hash * 314159 : hash;  // Yes, it's prime.
-
-    // Try other n-character names based on the hash.  We try one to three
-    // character identifiers.  For each length we try around 10 different names
-    // in a predictable order determined by the proposed name.  This is in order
-    // to make the renamer stable: small changes in the input should nornally
-    // result in relatively small changes in the output.
-    for (var n = 1; n <= 3; n++) {
-      int h = hash;
-      while (h > 10) {
-        var codes = <int>[_letterNumber(h)];
-        int h2 = h ~/ ALPHABET_CHARACTERS;
-        for (var i = 1; i < n; i++) {
-          codes.add(_alphaNumericNumber(h2));
-          h2 ~/= ALPHANUMERIC_CHARACTERS;
-        }
-        final candidate = new String.fromCharCodes(codes);
-        if (!usedNames.contains(candidate) && !jsReserved.contains(candidate)) {
-          return candidate;
-        }
-        // Try again with a slightly different hash.  After around 10 turns
-        // around this loop h is zero and we try a longer name.
-        h ~/= 7;
-      }
-    }
-
-    // If we can't find a hash based name in the three-letter space, then base
-    // the name on a letter and a counter.
-    proposedName = new String.fromCharCodes([_letterNumber(hash)]);
-    var i = 0;
-    while (usedNames.contains("$proposedName$i")) {
-      i++;
-    }
-    return "$proposedName$i";
-  }
-
-  int _calculateHash(String name) {
-    int h = 0;
-    for (int i = 0; i < name.length; i++) {
-      h += name.charCodeAt(i);
-      h &= 0xffffffff;
-      h += h << 10;
-      h &= 0xffffffff;
-      h ^= h >> 6;
-      h &= 0xffffffff;
-    }
-    return h;
-  }
-
-  int _letterNumber(int x) {
-    if (x >= ALPHABET_CHARACTERS) x %= ALPHABET_CHARACTERS;
-    if (x < 26) return $a + x;
-    return $A + x - 26;
-  }
-
-  int _alphaNumericNumber(int x) {
-    if (x >= ALPHANUMERIC_CHARACTERS) x %= ALPHANUMERIC_CHARACTERS;
-    if (x < 26) return $a + x;
-    if (x < 52) return $A + x - 26;
-    return $0 + x - 52;
-  }
-
-}