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| 1 | /* | ||
| 2 | * Copyright (c) 1998, 2000, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package javax.swing.text.html.parser; | ||
| 27 | |||
| 28 | /** | ||
| 29 | * A content model state. This is basically a list of pointers to | ||
| 30 | * the BNF expression representing the model (the ContentModel). | ||
| 31 | * Each element in a DTD has a content model which describes the | ||
| 32 | * elements that may occur inside, and the order in which they can | ||
| 33 | * occur. | ||
| 34 | * <p> | ||
| 35 | * Each time a token is reduced a new state is created. | ||
| 36 | * <p> | ||
| 37 | * See Annex H on page 556 of the SGML handbook for more information. | ||
| 38 | * | ||
| 39 | * @see Parser | ||
| 40 | * @see DTD | ||
| 41 | * @see Element | ||
| 42 | * @see ContentModel | ||
| 43 | * @author Arthur van Hoff | ||
| 44 | */ | ||
| 45 | class ContentModelState { | ||
| 46 | ContentModel model; | ||
| 47 | long value; | ||
| 48 | ContentModelState next; | ||
| 49 | |||
| 50 | /** | ||
| 51 | * Create a content model state for a content model. | ||
| 52 | */ | ||
| 53 | public ContentModelState(ContentModel model) { | ||
| 54 | this(model, null, 0); | ||
| 55 | } | ||
| 56 | |||
| 57 | /** | ||
| 58 | * Create a content model state for a content model given the | ||
| 59 | * remaining state that needs to be reduce. | ||
| 60 | */ | ||
| 61 | ContentModelState(Object content, ContentModelState next) { | ||
| 62 | this(content, next, 0); | ||
| 63 | } | ||
| 64 | |||
| 65 | /** | ||
| 66 | * Create a content model state for a content model given the | ||
| 67 | * remaining state that needs to be reduce. | ||
| 68 | */ | ||
| 69 | ContentModelState(Object content, ContentModelState next, long value) { | ||
| 70 | this.model = (ContentModel)content; | ||
| 71 | this.next = next; | ||
| 72 | this.value = value; | ||
| 73 | } | ||
| 74 | |||
| 75 | /** | ||
| 76 | * Return the content model that is relevant to the current state. | ||
| 77 | */ | ||
| 78 | public ContentModel getModel() { | ||
| 79 | ContentModel m = model; | ||
| 80 | for (int i = 0; i < value; i++) { | ||
| 81 | if (m.next != null) { | ||
| 82 | m = m.next; | ||
| 83 | } else { | ||
| 84 | return null; | ||
| 85 | } | ||
| 86 | } | ||
| 87 | return m; | ||
| 88 | } | ||
| 89 | |||
| 90 | /** | ||
| 91 | * Check if the state can be terminated. That is there are no more | ||
| 92 | * tokens required in the input stream. | ||
| 93 | * @return true if the model can terminate without further input | ||
| 94 | */ | ||
| 95 | public boolean terminate() { | ||
| 96 | switch (model.type) { | ||
| 97 | case '+': | ||
| 98 | if ((value == 0) && !(model).empty()) { | ||
| 99 | return false; | ||
| 100 | } | ||
| 101 | case '*': | ||
| 102 | case '?': | ||
| 103 | return (next == null) || next.terminate(); | ||
| 104 | |||
| 105 | case '|': | ||
| 106 | for (ContentModel m = (ContentModel)model.content ; m != null ; m = m.next) { | ||
| 107 | if (m.empty()) { | ||
| 108 | return (next == null) || next.terminate(); | ||
| 109 | } | ||
| 110 | } | ||
| 111 | return false; | ||
| 112 | |||
| 113 | case '&': { | ||
| 114 | ContentModel m = (ContentModel)model.content; | ||
| 115 | |||
| 116 | for (int i = 0 ; m != null ; i++, m = m.next) { | ||
| 117 | if ((value & (1L << i)) == 0) { | ||
| 118 | if (!m.empty()) { | ||
| 119 | return false; | ||
| 120 | } | ||
| 121 | } | ||
| 122 | } | ||
| 123 | return (next == null) || next.terminate(); | ||
| 124 | } | ||
| 125 | |||
| 126 | case ',': { | ||
| 127 | ContentModel m = (ContentModel)model.content; | ||
| 128 | for (int i = 0 ; i < value ; i++, m = m.next); | ||
| 129 | |||
| 130 | for (; (m != null) && m.empty() ; m = m.next); | ||
| 131 | if (m != null) { | ||
| 132 | return false; | ||
| 133 | } | ||
| 134 | return (next == null) || next.terminate(); | ||
| 135 | } | ||
| 136 | |||
| 137 | default: | ||
| 138 | return false; | ||
| 139 | } | ||
| 140 | } | ||
| 141 | |||
| 142 | /** | ||
| 143 | * Check if the state can be terminated. That is there are no more | ||
| 144 | * tokens required in the input stream. | ||
| 145 | * @return the only possible element that can occur next | ||
| 146 | */ | ||
| 147 | public Element first() { | ||
| 148 | switch (model.type) { | ||
| 149 | case '*': | ||
| 150 | case '?': | ||
| 151 | case '|': | ||
| 152 | case '&': | ||
| 153 | return null; | ||
| 154 | |||
| 155 | case '+': | ||
| 156 | return model.first(); | ||
| 157 | |||
| 158 | case ',': { | ||
| 159 | ContentModel m = (ContentModel)model.content; | ||
| 160 | for (int i = 0 ; i < value ; i++, m = m.next); | ||
| 161 | return m.first(); | ||
| 162 | } | ||
| 163 | |||
| 164 | default: | ||
| 165 | return model.first(); | ||
| 166 | } | ||
| 167 | } | ||
| 168 | |||
| 169 | /** | ||
| 170 | * Advance this state to a new state. An exception is thrown if the | ||
| 171 | * token is illegal at this point in the content model. | ||
| 172 | * @return next state after reducing a token | ||
| 173 | */ | ||
| 174 | public ContentModelState advance(Object token) { | ||
| 175 | switch (model.type) { | ||
| 176 | case '+': | ||
| 177 | if (model.first(token)) { | ||
| 178 | return new ContentModelState(model.content, | ||
| 179 | new ContentModelState(model, next, value + 1)).advance(token); | ||
| 180 | } | ||
| 181 | if (value != 0) { | ||
| 182 | if (next != null) { | ||
| 183 | return next.advance(token); | ||
| 184 | } else { | ||
| 185 | return null; | ||
| 186 | } | ||
| 187 | } | ||
| 188 | break; | ||
| 189 | |||
| 190 | case '*': | ||
| 191 | if (model.first(token)) { | ||
| 192 | return new ContentModelState(model.content, this).advance(token); | ||
| 193 | } | ||
| 194 | if (next != null) { | ||
| 195 | return next.advance(token); | ||
| 196 | } else { | ||
| 197 | return null; | ||
| 198 | } | ||
| 199 | |||
| 200 | case '?': | ||
| 201 | if (model.first(token)) { | ||
| 202 | return new ContentModelState(model.content, next).advance(token); | ||
| 203 | } | ||
| 204 | if (next != null) { | ||
| 205 | return next.advance(token); | ||
| 206 | } else { | ||
| 207 | return null; | ||
| 208 | } | ||
| 209 | |||
| 210 | case '|': | ||
| 211 | for (ContentModel m = (ContentModel)model.content ; m != null ; m = m.next) { | ||
| 212 | if (m.first(token)) { | ||
| 213 | return new ContentModelState(m, next).advance(token); | ||
| 214 | } | ||
| 215 | } | ||
| 216 | break; | ||
| 217 | |||
| 218 | case ',': { | ||
| 219 | ContentModel m = (ContentModel)model.content; | ||
| 220 | for (int i = 0 ; i < value ; i++, m = m.next); | ||
| 221 | |||
| 222 | if (m.first(token) || m.empty()) { | ||
| 223 | if (m.next == null) { | ||
| 224 | return new ContentModelState(m, next).advance(token); | ||
| 225 | } else { | ||
| 226 | return new ContentModelState(m, | ||
| 227 | new ContentModelState(model, next, value + 1)).advance(token); | ||
| 228 | } | ||
| 229 | } | ||
| 230 | break; | ||
| 231 | } | ||
| 232 | |||
| 233 | case '&': { | ||
| 234 | ContentModel m = (ContentModel)model.content; | ||
| 235 | boolean complete = true; | ||
| 236 | |||
| 237 | for (int i = 0 ; m != null ; i++, m = m.next) { | ||
| 238 | if ((value & (1L << i)) == 0) { | ||
| 239 | if (m.first(token)) { | ||
| 240 | return new ContentModelState(m, | ||
| 241 | new ContentModelState(model, next, value | (1L << i))).advance(token); | ||
| 242 | } | ||
| 243 | if (!m.empty()) { | ||
| 244 | complete = false; | ||
| 245 | } | ||
| 246 | } | ||
| 247 | } | ||
| 248 | if (complete) { | ||
| 249 | if (next != null) { | ||
| 250 | return next.advance(token); | ||
| 251 | } else { | ||
| 252 | return null; | ||
| 253 | } | ||
| 254 | } | ||
| 255 | break; | ||
| 256 | } | ||
| 257 | |||
| 258 | default: | ||
| 259 | if (model.content == token) { | ||
| 260 | if (next == null && (token instanceof Element) && | ||
| 261 | ((Element)token).content != null) { | ||
| 262 | return new ContentModelState(((Element)token).content); | ||
| 263 | } | ||
| 264 | return next; | ||
| 265 | } | ||
| 266 | // PENDING: Currently we don't correctly deal with optional start | ||
| 267 | // tags. This can most notably be seen with the 4.01 spec where | ||
| 268 | // TBODY's start and end tags are optional. | ||
| 269 | // Uncommenting this and the PENDING in ContentModel will | ||
| 270 | // correctly skip the omit tags, but the delegate is not notified. | ||
| 271 | // Some additional API needs to be added to track skipped tags, | ||
| 272 | // and this can then be added back. | ||
| 273 | /* | ||
| 274 | if ((model.content instanceof Element)) { | ||
| 275 | Element e = (Element)model.content; | ||
| 276 | |||
| 277 | if (e.omitStart() && e.content != null) { | ||
| 278 | return new ContentModelState(e.content, next).advance( | ||
| 279 | token); | ||
| 280 | } | ||
| 281 | } | ||
| 282 | */ | ||
| 283 | } | ||
| 284 | |||
| 285 | // We used to throw this exception at this point. However, it | ||
| 286 | // was determined that throwing this exception was more expensive | ||
| 287 | // than returning null, and we could not justify to ourselves why | ||
| 288 | // it was necessary to throw an exception, rather than simply | ||
| 289 | // returning null. I'm leaving it in a commented out state so | ||
| 290 | // that it can be easily restored if the situation ever arises. | ||
| 291 | // | ||
| 292 | // throw new IllegalArgumentException("invalid token: " + token); | ||
| 293 | return null; | ||
| 294 | } | ||
| 295 | } | ||