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Unified Diff: pkg/compiler/lib/src/js_backend/minify_namer.dart

Issue 693183006: Revert "Move dart2js from sdk/lib/_internal/compiler to pkg/compiler" (Closed) Base URL: https://dart.googlecode.com/svn/branches/bleeding_edge/dart
Patch Set: Created 6 years, 1 month ago
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Index: pkg/compiler/lib/src/js_backend/minify_namer.dart
diff --git a/pkg/compiler/lib/src/js_backend/minify_namer.dart b/pkg/compiler/lib/src/js_backend/minify_namer.dart
deleted file mode 100644
index a3182791dc285c6182fea6b83224b135a3336050..0000000000000000000000000000000000000000
--- a/pkg/compiler/lib/src/js_backend/minify_namer.dart
+++ /dev/null
@@ -1,225 +0,0 @@
-// 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.
-
-part of js_backend;
-
-/**
- * Assigns JavaScript identifiers to Dart variables, class-names and members.
- */
-class MinifyNamer extends Namer {
- MinifyNamer(Compiler compiler) : super(compiler) {
- reserveBackendNames();
- }
-
- String get isolateName => 'I';
- String get isolatePropertiesName => 'p';
- bool get shouldMinify => true;
-
- final String getterPrefix = 'g';
- final String setterPrefix = 's';
- final String callPrefix = ''; // this will create function names $<n>
-
- static const ALPHABET_CHARACTERS = 52; // a-zA-Z.
- static const ALPHANUMERIC_CHARACTERS = 62; // a-zA-Z0-9.
-
- // You can pass an invalid identifier to this and unlike its non-minifying
- // counterpart it will never return the proposedName as the new fresh name.
- String getFreshName(String proposedName,
- Set<String> usedNames,
- Map<String, String> suggestedNames,
- {bool ensureSafe: true}) {
- var freshName;
- var suggestion = suggestedNames[proposedName];
- if (suggestion != null && !usedNames.contains(suggestion)) {
- freshName = suggestion;
- } else {
- freshName = _getUnusedName(proposedName, usedNames);
- }
- usedNames.add(freshName);
- return freshName;
- }
-
- String getClosureVariableName(String name, int id) {
- if (id < ALPHABET_CHARACTERS) {
- return new String.fromCharCodes([_letterNumber(id)]);
- }
- return "${getMappedInstanceName('closure')}_$id";
- }
-
- void reserveBackendNames() {
- // From issue 7554. These should not be used on objects (as instance
- // variables) because they clash with names from the DOM.
- const reservedNativeProperties = const <String>[
- 'Q', 'a', 'b', 'c', 'd', 'e', 'f', 'r', 'x', 'y', 'z',
- // 2-letter:
- 'ch', 'cx', 'cy', 'db', 'dx', 'dy', 'fr', 'fx', 'fy', 'go', 'id', 'k1',
- 'k2', 'k3', 'k4', 'r1', 'r2', 'rx', 'ry', 'x1', 'x2', 'y1', 'y2',
- // 3-letter:
- 'add', 'all', 'alt', 'arc', 'CCW', 'cmp', 'dir', 'end', 'get', 'in1',
- 'in2', 'INT', 'key', 'log', 'low', 'm11', 'm12', 'm13', 'm14', 'm21',
- 'm22', 'm23', 'm24', 'm31', 'm32', 'm33', 'm34', 'm41', 'm42', 'm43',
- 'm44', 'max', 'min', 'now', 'ONE', 'put', 'red', 'rel', 'rev', 'RGB',
- 'sdp', 'set', 'src', 'tag', 'top', 'uid', 'uri', 'url', 'URL',
- // 4-letter:
- 'abbr', 'atob', 'Attr', 'axes', 'axis', 'back', 'BACK', 'beta', 'bias',
- 'Blob', 'blue', 'blur', 'BLUR', 'body', 'BOOL', 'BOTH', 'btoa', 'BYTE',
- 'cite', 'clip', 'code', 'cols', 'cues', 'data', 'DECR', 'DONE', 'face',
- 'file', 'File', 'fill', 'find', 'font', 'form', 'gain', 'hash', 'head',
- 'high', 'hint', 'host', 'href', 'HRTF', 'IDLE', 'INCR', 'info', 'INIT',
- 'isId', 'item', 'KEEP', 'kind', 'knee', 'lang', 'left', 'LESS', 'line',
- 'link', 'list', 'load', 'loop', 'mode', 'name', 'Node', 'None', 'NONE',
- 'only', 'open', 'OPEN', 'ping', 'play', 'port', 'rect', 'Rect', 'refX',
- 'refY', 'RGBA', 'root', 'rows', 'save', 'seed', 'seek', 'self', 'send',
- 'show', 'SINE', 'size', 'span', 'stat', 'step', 'stop', 'tags', 'text',
- 'Text', 'time', 'type', 'view', 'warn', 'wrap', 'ZERO'];
-
- for (var name in reservedNativeProperties) {
- if (name.length < 2) {
- instanceNameMap[name] = name;
- }
- usedInstanceNames.add(name);
- // Getter and setter names are autogenerated by prepending 'g' and 's' to
- // field names. Therefore there are some field names we don't want to
- // use. It is implicit in the next line that the banned prefix is
- // only one character.
- if (_hasBannedPrefix(name)) usedInstanceNames.add(name.substring(1));
- }
-
- // These popular names are present in most programs and deserve
- // single character minified names. We could determine the popular names
- // individually per program, but that would mean that the output of the
- // minifier was less stable from version to version of the program being
- // minified.
- _populateSuggestedNames(
- suggestedInstanceNames,
- usedInstanceNames,
- const <String>[
- r'$add', r'add$1', r'$and', r'codeUnitAt$1', r'$or',
- r'current', r'$shr', r'$eq', r'$ne',
- r'getPrototypeOf', r'hasOwnProperty', r'$index', r'$indexSet',
- r'$isJavaScriptIndexingBehavior', r'$xor',
- r'iterator', r'length', r'$lt', r'$gt', r'$le', r'$ge',
- r'moveNext$0', r'node', r'on', r'$negate', r'push', r'self',
- r'start', r'target', r'$shl', r'value', r'width', r'style',
- r'noSuchMethod$1', r'$mul', r'$div', r'$sub', r'$not', r'$mod',
- r'$tdiv']);
-
- _populateSuggestedNames(
- suggestedGlobalNames,
- usedGlobalNames,
- const <String>[
- r'Object', 'wrapException', r'$eq', r'S', r'ioore',
- r'UnsupportedError$', r'length', r'$sub',
- r'getInterceptor$JSArrayJSString', r'$add',
- r'$gt', r'$ge', r'$lt', r'$le', r'add', r'getInterceptor$JSNumber',
- r'iterator', r'$index', r'iae', r'getInterceptor$JSArray',
- r'ArgumentError$', r'BoundClosure', r'StateError$',
- r'getInterceptor', r'max', r'$mul', r'List_List', r'Map_Map',
- r'getInterceptor$JSString', r'$div', r'$indexSet',
- r'List_List$from', r'Set_Set$from', r'toString', r'toInt', r'min',
- r'StringBuffer_StringBuffer', r'contains1', r'WhereIterable$',
- r'RangeError$value', r'JSString', r'JSNumber',
- r'JSArray', r'createInvocationMirror'
- ]);
- }
-
- void _populateSuggestedNames(Map<String, String> suggestionMap,
- Set<String> used,
- List<String> suggestions) {
- int c = $a - 1;
- String letter;
- for (String name in suggestions) {
- do {
- assert(c != $Z);
- c = (c == $z) ? $A : c + 1;
- letter = new String.fromCharCodes([c]);
- } while (used.contains(letter));
- assert(suggestionMap[name] == null);
- suggestionMap[name] = letter;
- }
- }
-
-
- // This gets a minified name based on a hash of the proposed name. This
- // is slightly less efficient than just getting the next name in a series,
- // but it means that small changes in the input program will give smallish
- // changes in the output, which can be useful for diffing etc.
- String _getUnusedName(String proposedName, Set<String> usedNames) {
- int hash = _calculateHash(proposedName);
- // Avoid very small hashes that won't try many names.
- hash = hash < 1000 ? hash * 314159 : hash; // Yes, it's prime.
-
- // Try other n-character names based on the hash. We try one to three
- // character identifiers. For each length we try around 10 different names
- // in a predictable order determined by the proposed name. This is in order
- // to make the renamer stable: small changes in the input should nornally
- // result in relatively small changes in the output.
- for (var n = 2; n <= 3; n++) {
- int h = hash;
- while (h > 10) {
- var codes = <int>[_letterNumber(h)];
- int h2 = h ~/ ALPHABET_CHARACTERS;
- for (var i = 1; i < n; i++) {
- codes.add(_alphaNumericNumber(h2));
- h2 ~/= ALPHANUMERIC_CHARACTERS;
- }
- final candidate = new String.fromCharCodes(codes);
- if (!usedNames.contains(candidate) &&
- !jsReserved.contains(candidate) &&
- !_hasBannedPrefix(candidate)) {
- return candidate;
- }
- // Try again with a slightly different hash. After around 10 turns
- // around this loop h is zero and we try a longer name.
- h ~/= 7;
- }
- }
-
- // If we can't find a hash based name in the three-letter space, then base
- // the name on a letter and a counter.
- var startLetter = new String.fromCharCodes([_letterNumber(hash)]);
- var i = 0;
- while (usedNames.contains("$startLetter$i")) {
- i++;
- }
- // We don't need to check for banned prefix because the name is in the form
- // xnnn, where nnn is a number. There can be no getter or setter called
- // gnnn since that would imply a numeric field name.
- return "$startLetter$i";
- }
-
- /// Instance members starting with g and s are reserved for getters and
- /// setters.
- bool _hasBannedPrefix(String name) {
- int code = name.codeUnitAt(0);
- return code == $g || code == $s;
- }
-
- int _calculateHash(String name) {
- int h = 0;
- for (int i = 0; i < name.length; i++) {
- h += name.codeUnitAt(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;
- }
-
-}
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