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| 1 // Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file | |
| 2 // for details. All rights reserved. Use of this source code is governed by a | |
| 3 // BSD-style license that can be found in the LICENSE file. | |
| 4 | |
| 5 library template_binding.src.mustache_tokens; | |
| 6 | |
| 7 import 'package:observe/observe.dart'; | |
| 8 | |
| 9 // Dart note: this was added to decouple the parse function below from the rest | |
| 10 // of template_binding. This allows using this code in command-line tools as | |
| 11 // well. | |
| 12 typedef Function DelegateFunctionFactory(String pathString); | |
| 13 | |
| 14 /** | |
| 15 * Represents a set of parsed tokens from a {{ mustache binding expression }}. | |
| 16 * This can be created by calling [parse]. | |
| 17 * | |
| 18 * For performance reasons the data is stored in one linear array in [_tokens]. | |
| 19 * This class wraps that array and provides accessors in an attempt to make the | |
| 20 * pattern easier to understand. See [length] and [getText] for example. | |
| 21 */ | |
| 22 class MustacheTokens { | |
| 23 // Constants for indexing into the exploded structs in [_tokens] . | |
| 24 static const _TOKEN_TEXT = 0; | |
| 25 static const _TOKEN_ONETIME = 1; | |
| 26 static const _TOKEN_PATH = 2; | |
| 27 static const _TOKEN_PREPAREFN = 3; | |
| 28 static const _TOKEN_SIZE = 4; | |
| 29 | |
| 30 // There is 1 extra entry for the end text. | |
| 31 static const _TOKEN_ENDTEXT = 1; | |
| 32 | |
| 33 bool get hasOnePath => _tokens.length == _TOKEN_SIZE + _TOKEN_ENDTEXT; | |
| 34 bool get isSimplePath => hasOnePath && | |
| 35 _tokens[_TOKEN_TEXT] == '' && _tokens[_TOKEN_SIZE + _TOKEN_TEXT] == ''; | |
| 36 | |
| 37 /** | |
| 38 * [TEXT, (ONE_TIME?, PATH, DELEGATE_FN, TEXT)+] if there is at least one | |
| 39 * mustache. | |
| 40 */ | |
| 41 final List _tokens; | |
| 42 | |
| 43 final bool onlyOneTime; | |
| 44 | |
| 45 // Dart note: I think this is cached in JavaScript to avoid an extra | |
| 46 // allocation per template instance. Seems reasonable, so we do the same. | |
| 47 Function _combinator; | |
| 48 Function get combinator => _combinator; | |
| 49 | |
| 50 MustacheTokens._(this._tokens, this.onlyOneTime) { | |
| 51 // Should be: [TEXT, (ONE_TIME?, PATH, DELEGATE_FN, TEXT)+]. | |
| 52 assert((_tokens.length - _TOKEN_ENDTEXT) % _TOKEN_SIZE == 0); | |
| 53 | |
| 54 _combinator = hasOnePath ? _singleCombinator : _listCombinator; | |
| 55 } | |
| 56 | |
| 57 int get length => _tokens.length ~/ _TOKEN_SIZE; | |
| 58 | |
| 59 /** | |
| 60 * Gets the [i]th text entry. Note that [length] can be passed to get the | |
| 61 * final text entry. | |
| 62 */ | |
| 63 String getText(int i) => _tokens[i * _TOKEN_SIZE + _TOKEN_TEXT]; | |
| 64 | |
| 65 /** Gets the oneTime flag for the [i]th token. */ | |
| 66 bool getOneTime(int i) => _tokens[i * _TOKEN_SIZE + _TOKEN_ONETIME]; | |
| 67 | |
| 68 /** Gets the path for the [i]th token. */ | |
| 69 PropertyPath getPath(int i) => _tokens[i * _TOKEN_SIZE + _TOKEN_PATH]; | |
| 70 | |
| 71 /** Gets the prepareBinding function for the [i]th token. */ | |
| 72 Function getPrepareBinding(int i) => | |
| 73 _tokens[i * _TOKEN_SIZE + _TOKEN_PREPAREFN]; | |
| 74 | |
| 75 | |
| 76 /** | |
| 77 * Parses {{ mustache }} bindings. | |
| 78 * | |
| 79 * Returns null if there are no matches. Otherwise returns the parsed tokens. | |
| 80 */ | |
| 81 static MustacheTokens parse(String s, [DelegateFunctionFactory fnFactory]) { | |
| 82 if (s == null || s.isEmpty) return null; | |
| 83 | |
| 84 var tokens = null; | |
| 85 var length = s.length; | |
| 86 var lastIndex = 0; | |
| 87 var onlyOneTime = true; | |
| 88 while (lastIndex < length) { | |
| 89 var startIndex = s.indexOf('{{', lastIndex); | |
| 90 var oneTimeStart = s.indexOf('[[', lastIndex); | |
| 91 var oneTime = false; | |
| 92 var terminator = '}}'; | |
| 93 | |
| 94 if (oneTimeStart >= 0 && | |
| 95 (startIndex < 0 || oneTimeStart < startIndex)) { | |
| 96 startIndex = oneTimeStart; | |
| 97 oneTime = true; | |
| 98 terminator = ']]'; | |
| 99 } | |
| 100 | |
| 101 var endIndex = -1; | |
| 102 if (startIndex >= 0) { | |
| 103 endIndex = s.indexOf(terminator, startIndex + 2); | |
| 104 } | |
| 105 | |
| 106 if (endIndex < 0) { | |
| 107 if (tokens == null) return null; | |
| 108 | |
| 109 tokens.add(s.substring(lastIndex)); // TEXT | |
| 110 break; | |
| 111 } | |
| 112 | |
| 113 if (tokens == null) tokens = []; | |
| 114 tokens.add(s.substring(lastIndex, startIndex)); // TEXT | |
| 115 var pathString = s.substring(startIndex + 2, endIndex).trim(); | |
| 116 tokens.add(oneTime); // ONETIME? | |
| 117 onlyOneTime = onlyOneTime && oneTime; | |
| 118 var delegateFn = fnFactory == null ? null : fnFactory(pathString); | |
| 119 // Don't try to parse the expression if there's a prepareBinding function | |
| 120 if (delegateFn == null) { | |
| 121 tokens.add(new PropertyPath(pathString)); // PATH | |
| 122 } else { | |
| 123 tokens.add(null); | |
| 124 } | |
| 125 tokens.add(delegateFn); // DELEGATE_FN | |
| 126 | |
| 127 lastIndex = endIndex + 2; | |
| 128 } | |
| 129 | |
| 130 if (lastIndex == length) tokens.add(''); // TEXT | |
| 131 | |
| 132 return new MustacheTokens._(tokens, onlyOneTime); | |
| 133 } | |
| 134 | |
| 135 | |
| 136 // Dart note: split "combinator" into the single/list variants, so the | |
| 137 // argument can be typed. | |
| 138 String _singleCombinator(Object value) { | |
| 139 if (value == null) value = ''; | |
| 140 return '${getText(0)}$value${getText(length)}'; | |
| 141 } | |
| 142 | |
| 143 String _listCombinator(List<Object> values) { | |
| 144 var newValue = new StringBuffer(getText(0)); | |
| 145 int len = this.length; | |
| 146 for (var i = 0; i < len; i++) { | |
| 147 var value = values[i]; | |
| 148 if (value != null) newValue.write(value); | |
| 149 newValue.write(getText(i + 1)); | |
| 150 } | |
| 151 return newValue.toString(); | |
| 152 } | |
| 153 } | |
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Chromium Code Reviews
Issue 1400473008:
Roll Observatory packages and add a roll script (Closed)
Base URL: git@github.com:dart-lang/observatory_pub_packages.git@master