| /* |
| * Copyright (c) 1998, 2014, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package javax.swing.text.html.parser; |
| |
| /** |
| * A content model state. This is basically a list of pointers to |
| * the BNF expression representing the model (the ContentModel). |
| * Each element in a DTD has a content model which describes the |
| * elements that may occur inside, and the order in which they can |
| * occur. |
| * <p> |
| * Each time a token is reduced a new state is created. |
| * <p> |
| * See Annex H on page 556 of the SGML handbook for more information. |
| * |
| * @see Parser |
| * @see DTD |
| * @see Element |
| * @see ContentModel |
| * @author Arthur van Hoff |
| */ |
| class ContentModelState { |
| ContentModel model; |
| long value; |
| ContentModelState next; |
| |
| /** |
| * Create a content model state for a content model. |
| */ |
| public ContentModelState(ContentModel model) { |
| this(model, null, 0); |
| } |
| |
| /** |
| * Create a content model state for a content model given the |
| * remaining state that needs to be reduce. |
| */ |
| ContentModelState(Object content, ContentModelState next) { |
| this(content, next, 0); |
| } |
| |
| /** |
| * Create a content model state for a content model given the |
| * remaining state that needs to be reduce. |
| */ |
| ContentModelState(Object content, ContentModelState next, long value) { |
| this.model = (ContentModel)content; |
| this.next = next; |
| this.value = value; |
| } |
| |
| /** |
| * Return the content model that is relevant to the current state. |
| */ |
| public ContentModel getModel() { |
| ContentModel m = model; |
| for (int i = 0; i < value; i++) { |
| if (m.next != null) { |
| m = m.next; |
| } else { |
| return null; |
| } |
| } |
| return m; |
| } |
| |
| /** |
| * Check if the state can be terminated. That is there are no more |
| * tokens required in the input stream. |
| * @return true if the model can terminate without further input |
| */ |
| @SuppressWarnings("fallthrough") |
| public boolean terminate() { |
| switch (model.type) { |
| case '+': |
| if ((value == 0) && !(model).empty()) { |
| return false; |
| } |
| // Fall through |
| case '*': |
| case '?': |
| return (next == null) || next.terminate(); |
| |
| case '|': |
| for (ContentModel m = (ContentModel)model.content ; m != null ; m = m.next) { |
| if (m.empty()) { |
| return (next == null) || next.terminate(); |
| } |
| } |
| return false; |
| |
| case '&': { |
| ContentModel m = (ContentModel)model.content; |
| |
| for (int i = 0 ; m != null ; i++, m = m.next) { |
| if ((value & (1L << i)) == 0) { |
| if (!m.empty()) { |
| return false; |
| } |
| } |
| } |
| return (next == null) || next.terminate(); |
| } |
| |
| case ',': { |
| ContentModel m = (ContentModel)model.content; |
| for (int i = 0 ; i < value ; i++, m = m.next); |
| |
| for (; (m != null) && m.empty() ; m = m.next); |
| if (m != null) { |
| return false; |
| } |
| return (next == null) || next.terminate(); |
| } |
| |
| default: |
| return false; |
| } |
| } |
| |
| /** |
| * Check if the state can be terminated. That is there are no more |
| * tokens required in the input stream. |
| * @return the only possible element that can occur next |
| */ |
| public Element first() { |
| switch (model.type) { |
| case '*': |
| case '?': |
| case '|': |
| case '&': |
| return null; |
| |
| case '+': |
| return model.first(); |
| |
| case ',': { |
| ContentModel m = (ContentModel)model.content; |
| for (int i = 0 ; i < value ; i++, m = m.next); |
| return m.first(); |
| } |
| |
| default: |
| return model.first(); |
| } |
| } |
| |
| /** |
| * Advance this state to a new state. An exception is thrown if the |
| * token is illegal at this point in the content model. |
| * @return next state after reducing a token |
| */ |
| public ContentModelState advance(Object token) { |
| switch (model.type) { |
| case '+': |
| if (model.first(token)) { |
| return new ContentModelState(model.content, |
| new ContentModelState(model, next, value + 1)).advance(token); |
| } |
| if (value != 0) { |
| if (next != null) { |
| return next.advance(token); |
| } else { |
| return null; |
| } |
| } |
| break; |
| |
| case '*': |
| if (model.first(token)) { |
| return new ContentModelState(model.content, this).advance(token); |
| } |
| if (next != null) { |
| return next.advance(token); |
| } else { |
| return null; |
| } |
| |
| case '?': |
| if (model.first(token)) { |
| return new ContentModelState(model.content, next).advance(token); |
| } |
| if (next != null) { |
| return next.advance(token); |
| } else { |
| return null; |
| } |
| |
| case '|': |
| for (ContentModel m = (ContentModel)model.content ; m != null ; m = m.next) { |
| if (m.first(token)) { |
| return new ContentModelState(m, next).advance(token); |
| } |
| } |
| break; |
| |
| case ',': { |
| ContentModel m = (ContentModel)model.content; |
| for (int i = 0 ; i < value ; i++, m = m.next); |
| |
| if (m.first(token) || m.empty()) { |
| if (m.next == null) { |
| return new ContentModelState(m, next).advance(token); |
| } else { |
| return new ContentModelState(m, |
| new ContentModelState(model, next, value + 1)).advance(token); |
| } |
| } |
| break; |
| } |
| |
| case '&': { |
| ContentModel m = (ContentModel)model.content; |
| boolean complete = true; |
| |
| for (int i = 0 ; m != null ; i++, m = m.next) { |
| if ((value & (1L << i)) == 0) { |
| if (m.first(token)) { |
| return new ContentModelState(m, |
| new ContentModelState(model, next, value | (1L << i))).advance(token); |
| } |
| if (!m.empty()) { |
| complete = false; |
| } |
| } |
| } |
| if (complete) { |
| if (next != null) { |
| return next.advance(token); |
| } else { |
| return null; |
| } |
| } |
| break; |
| } |
| |
| default: |
| if (model.content == token) { |
| if (next == null && (token instanceof Element) && |
| ((Element)token).content != null) { |
| return new ContentModelState(((Element)token).content); |
| } |
| return next; |
| } |
| // PENDING: Currently we don't correctly deal with optional start |
| // tags. This can most notably be seen with the 4.01 spec where |
| // TBODY's start and end tags are optional. |
| // Uncommenting this and the PENDING in ContentModel will |
| // correctly skip the omit tags, but the delegate is not notified. |
| // Some additional API needs to be added to track skipped tags, |
| // and this can then be added back. |
| /* |
| if ((model.content instanceof Element)) { |
| Element e = (Element)model.content; |
| |
| if (e.omitStart() && e.content != null) { |
| return new ContentModelState(e.content, next).advance( |
| token); |
| } |
| } |
| */ |
| } |
| |
| // We used to throw this exception at this point. However, it |
| // was determined that throwing this exception was more expensive |
| // than returning null, and we could not justify to ourselves why |
| // it was necessary to throw an exception, rather than simply |
| // returning null. I'm leaving it in a commented out state so |
| // that it can be easily restored if the situation ever arises. |
| // |
| // throw new IllegalArgumentException("invalid token: " + token); |
| return null; |
| } |
| } |