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 * 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,

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 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package javax.swing.text.html;

import sun.swing.SwingUtilities2;

import java.util.*;

import java.awt.*;

import java.io.*;

import java.net.*;

import javax.swing.Icon;

import javax.swing.ImageIcon;

import javax.swing.UIManager;

import javax.swing.border.*;

import javax.swing.event.ChangeListener;

import javax.swing.text.*;

/**

 * Support for defining the visual characteristics of

 * HTML views being rendered.  The StyleSheet is used to

 * translate the HTML model into visual characteristics.

 * This enables views to be customized by a look-and-feel,

 * multiple views over the same model can be rendered

 * differently, etc.  This can be thought of as a CSS

 * rule repository.  The key for CSS attributes is an

 * object of type CSS.Attribute.  The type of the value

 * is up to the StyleSheet implementation, but the

 * <code>toString</code> method is required

 * to return a string representation of CSS value.

 * <p>

 * The primary entry point for HTML View implementations

 * to get their attributes is the

 * {@link #getViewAttributes getViewAttributes}

 * method.  This should be implemented to establish the

 * desired policy used to associate attributes with the view.

 * Each HTMLEditorKit (i.e. and therefore each associated

 * JEditorPane) can have its own StyleSheet, but by default one

 * sheet will be shared by all of the HTMLEditorKit instances.

 * HTMLDocument instance can also have a StyleSheet, which

 * holds the document-specific CSS specifications.

 * <p>

 * In order for Views to store less state and therefore be

 * more lightweight, the StyleSheet can act as a factory for

 * painters that handle some of the rendering tasks.  This allows

 * implementations to determine what they want to cache

 * and have the sharing potentially at the level that a

 * selector is common to multiple views.  Since the StyleSheet

 * may be used by views over multiple documents and typically

 * the HTML attributes don't effect the selector being used,

 * the potential for sharing is significant.

 * <p>

 * The rules are stored as named styles, and other information

 * is stored to translate the context of an element to a

 * rule quickly.  The following code fragment will display

 * the named styles, and therefore the CSS rules contained.

 * <pre><code>

 *  

 *   import java.util.*;

 *   import javax.swing.text.*;

 *   import javax.swing.text.html.*;

 *  

 *   public class ShowStyles {

 *  

 *       public static void main(String[] args) {

 *         HTMLEditorKit kit = new HTMLEditorKit();

 *         HTMLDocument doc = (HTMLDocument) kit.createDefaultDocument();

 *         StyleSheet styles = doc.getStyleSheet();

 *  

 *         Enumeration rules = styles.getStyleNames();

 *         while (rules.hasMoreElements()) {

 *             String name = (String) rules.nextElement();

 *             Style rule = styles.getStyle(name);

 *             System.out.println(rule.toString());

 *         }

 *         System.exit(0);

 *       }

 *   }

 *  

 * </code></pre>

 * <p>

 * The semantics for when a CSS style should overide visual attributes

 * defined by an element are not well defined. For example, the html

 * <code>&lt;body bgcolor=red&gt;</code> makes the body have a red

 * background. But if the html file also contains the CSS rule

 * <code>body { background: blue }</code> it becomes less clear as to

 * what color the background of the body should be. The current

 * implementation gives visual attributes defined in the element the

 * highest precedence, that is they are always checked before any styles.

 * Therefore, in the previous example the background would have a

 * red color as the body element defines the background color to be red.

 * <p>

 * As already mentioned this supports CSS. We don't support the full CSS

 * spec. Refer to the javadoc of the CSS class to see what properties

 * we support. The two major CSS parsing related

 * concepts we do not currently

 * support are pseudo selectors, such as <code>A:link { color: red }</code>,

 * and the <code>important</code> modifier.

 *

 * @implNote This implementation is currently

 * incomplete.  It can be replaced with alternative implementations

 * that are complete.  Future versions of this class will provide

 * better CSS support.

 *

 * @author  Timothy Prinzing

 * @author  Sunita Mani

 * @author  Sara Swanson

 * @author  Jill Nakata

 */

@SuppressWarnings("serial") // Superclass is not serializable across versions

public class StyleSheet extends StyleContext {

    // As the javadoc states, this class maintains a mapping between

    // a CSS selector (such as p.bar) and a Style.

    // This consists of a number of parts:

    // . Each selector is broken down into its constituent simple selectors,

    //   and stored in an inverted graph, for example:

    //     p { color: red } ol p { font-size: 10pt } ul p { font-size: 12pt }

    //   results in the graph:

    //          root

    //           |

    //           p

    //          / \

    //         ol ul

    //   each node (an instance of SelectorMapping) has an associated

    //   specificity and potentially a Style.

    // . Every rule that is asked for (either by way of getRule(String) or

    //   getRule(HTML.Tag, Element)) results in a unique instance of

    //   ResolvedStyle. ResolvedStyles contain the AttributeSets from the

    //   SelectorMapping.

    // . When a new rule is created it is inserted into the graph, and

    //   the AttributeSets of each ResolvedStyles are updated appropriately.

    // . This class creates special AttributeSets, LargeConversionSet and

    //   SmallConversionSet, that maintain a mapping between StyleConstants

    //   and CSS so that developers that wish to use the StyleConstants

    //   methods can do so.

    // . When one of the AttributeSets is mutated by way of a

    //   StyleConstants key, all the associated CSS keys are removed. This is

    //   done so that the two representations don't get out of sync. For

    //   example, if the developer adds StyleConstants.BOLD, FALSE to an

    //   AttributeSet that contains HTML.Tag.B, the HTML.Tag.B entry will

    //   be removed.

    /**

     * Construct a StyleSheet

     */

    public StyleSheet() {

        super();

        selectorMapping = new SelectorMapping(0);

        resolvedStyles = new Hashtable<String, ResolvedStyle>();

        if (css == null) {

            css = new CSS();

        }

    }

    /**

     * Fetches the style to use to render the given type

     * of HTML tag.  The element given is representing

     * the tag and can be used to determine the nesting

     * for situations where the attributes will differ

     * if nesting inside of elements.

     *

     * @param t the type to translate to visual attributes

     * @param e the element representing the tag; the element

     *  can be used to determine the nesting for situations where

     *  the attributes will differ if nested inside of other

     *  elements

     * @return the set of CSS attributes to use to render

     *  the tag

     */

    public Style getRule(HTML.Tag t, Element e) {

        SearchBuffer sb = SearchBuffer.obtainSearchBuffer();

        try {

            // Build an array of all the parent elements.

            @SuppressWarnings("unchecked")

            Vector<Element> searchContext = sb.getVector();

            for (Element p = e; p != null; p = p.getParentElement()) {

                searchContext.addElement(p);

            }

            // Build a fully qualified selector.

            int              n = searchContext.size();

            StringBuffer     cacheLookup = sb.getStringBuffer();

            AttributeSet     attr;

            String           eName;

            Object           name;

            // >= 1 as the HTML.Tag for the 0th element is passed in.

            for (int counter = n - 1; counter >= 1; counter--) {

                e = searchContext.elementAt(counter);

                attr = e.getAttributes();

                name = attr.getAttribute(StyleConstants.NameAttribute);

                eName = name.toString();

                cacheLookup.append(eName);

                if (attr != null) {

                    if (attr.isDefined(HTML.Attribute.ID)) {

                        cacheLookup.append('#');

                        cacheLookup.append(attr.getAttribute

                                           (HTML.Attribute.ID));

                    }

                    else if (attr.isDefined(HTML.Attribute.CLASS)) {

                        cacheLookup.append('.');

                        cacheLookup.append(attr.getAttribute

                                           (HTML.Attribute.CLASS));

                    }

                }

                cacheLookup.append(' ');

            }

            cacheLookup.append(t.toString());

            e = searchContext.elementAt(0);

            attr = e.getAttributes();

            if (e.isLeaf()) {

                // For leafs, we use the second tier attributes.

                Object testAttr = attr.getAttribute(t);

                if (testAttr instanceof AttributeSet) {

                    attr = (AttributeSet)testAttr;

                }

                else {

                    attr = null;

                }

            }

            if (attr != null) {

                if (attr.isDefined(HTML.Attribute.ID)) {

                    cacheLookup.append('#');

                    cacheLookup.append(attr.getAttribute(HTML.Attribute.ID));

                }

                else if (attr.isDefined(HTML.Attribute.CLASS)) {

                    cacheLookup.append('.');

                    cacheLookup.append(attr.getAttribute

                                       (HTML.Attribute.CLASS));

                }

            }

            Style style = getResolvedStyle(cacheLookup.toString(),

                                           searchContext, t);

            return style;

        }

        finally {

            SearchBuffer.releaseSearchBuffer(sb);

        }

    }

    /**

     * Fetches the rule that best matches the selector given

     * in string form. Where <code>selector</code> is a space separated

     * String of the element names. For example, <code>selector</code>

     * might be 'html body tr td''<p>

     * The attributes of the returned Style will change

     * as rules are added and removed. That is if you to ask for a rule

     * with a selector "table p" and a new rule was added with a selector

     * of "p" the returned Style would include the new attributes from

     * the rule "p".

     *

     * @param selector a space separated String of the element names.

     * @return the rule that best matches the selector.

     */

    public Style getRule(String selector) {

        selector = cleanSelectorString(selector);

        if (selector != null) {

            Style style = getResolvedStyle(selector);

            return style;

        }

        return null;

    }

    /**

     * Adds a set of rules to the sheet.  The rules are expected to

     * be in valid CSS format.  Typically this would be called as

     * a result of parsing a <style> tag.

     *

     * @param rule a set of rules

     */

    public void addRule(String rule) {

        if (rule != null) {

            //tweaks to control display properties

            //see BasicEditorPaneUI

            final String baseUnitsDisable = "BASE_SIZE_DISABLE";

            final String baseUnits = "BASE_SIZE ";

            final String w3cLengthUnitsEnable = "W3C_LENGTH_UNITS_ENABLE";

            final String w3cLengthUnitsDisable = "W3C_LENGTH_UNITS_DISABLE";

            if (rule == baseUnitsDisable) {

                sizeMap = sizeMapDefault;

            } else if (rule.startsWith(baseUnits)) {

                rebaseSizeMap(Integer.

                              parseInt(rule.substring(baseUnits.length())));

            } else if (rule == w3cLengthUnitsEnable) {

                w3cLengthUnits = true;

            } else if (rule == w3cLengthUnitsDisable) {

                w3cLengthUnits = false;

            } else {

                CssParser parser = new CssParser();

                try {

                    parser.parse(getBase(), new StringReader(rule), false, false);

                } catch (IOException ioe) { }

            }

        }

    }

    /**

     * Translates a CSS declaration to an AttributeSet that represents

     * the CSS declaration.  Typically this would be called as a

     * result of encountering an HTML style attribute.

     *

     * @param decl a CSS declaration

     * @return a set of attributes that represents the CSS declaration.

     */

    public AttributeSet getDeclaration(String decl) {

        if (decl == null) {

            return SimpleAttributeSet.EMPTY;

        }

        CssParser parser = new CssParser();

        return parser.parseDeclaration(decl);

    }

    /**

     * Loads a set of rules that have been specified in terms of

     * CSS1 grammar.  If there are collisions with existing rules,

     * the newly specified rule will win.

     *

     * @param in the stream to read the CSS grammar from

     * @param ref the reference URL.  This value represents the

     *  location of the stream and may be null.  All relative

     *  URLs specified in the stream will be based upon this

     *  parameter.

     * @throws java.io.IOException if I/O error occured.

     */

    public void loadRules(Reader in, URL ref) throws IOException {

        CssParser parser = new CssParser();

        parser.parse(ref, in, false, false);

    }

    /**

     * Fetches a set of attributes to use in the view for

     * displaying.  This is basically a set of attributes that

     * can be used for View.getAttributes.

     *

     * @param v a view

     * @return the of attributes

     */

    public AttributeSet getViewAttributes(View v) {

        return new ViewAttributeSet(v);

    }

    /**

     * Removes a named style previously added to the document.

     *

     * @param nm  the name of the style to remove

     */

    public void removeStyle(String nm) {

        Style       aStyle = getStyle(nm);

        if (aStyle != null) {

            String selector = cleanSelectorString(nm);

            String[] selectors = getSimpleSelectors(selector);

            synchronized(this) {

                SelectorMapping mapping = getRootSelectorMapping();

                for (int i = selectors.length - 1; i >= 0; i--) {

                    mapping = mapping.getChildSelectorMapping(selectors[i],

                                                              true);

                }

                Style rule = mapping.getStyle();

                if (rule != null) {

                    mapping.setStyle(null);

                    if (resolvedStyles.size() > 0) {

                        Enumeration<ResolvedStyle> values = resolvedStyles.elements();

                        while (values.hasMoreElements()) {

                            ResolvedStyle style = values.nextElement();

                            style.removeStyle(rule);

                        }

                    }

                }

            }

        }

        super.removeStyle(nm);

    }

    /**

     * Adds the rules from the StyleSheet <code>ss</code> to those of

     * the receiver. <code>ss's</code> rules will override the rules of

     * any previously added style sheets. An added StyleSheet will never

     * override the rules of the receiving style sheet.

     *

     * @param ss a StyleSheet

     * @since 1.3

     */

    public void addStyleSheet(StyleSheet ss) {

        synchronized(this) {

            if (linkedStyleSheets == null) {

                linkedStyleSheets = new Vector<StyleSheet>();

            }

            if (!linkedStyleSheets.contains(ss)) {

                int index = 0;

                if (ss instanceof javax.swing.plaf.UIResource

                    && linkedStyleSheets.size() > 1) {

                    index = linkedStyleSheets.size() - 1;

                }

                linkedStyleSheets.insertElementAt(ss, index);

                linkStyleSheetAt(ss, index);

            }

        }

    }

    /**

     * Removes the StyleSheet <code>ss</code> from those of the receiver.

     *

     * @param ss a StyleSheet

     * @since 1.3

     */

    public void removeStyleSheet(StyleSheet ss) {

        synchronized(this) {

            if (linkedStyleSheets != null) {

                int index = linkedStyleSheets.indexOf(ss);

                if (index != -1) {

                    linkedStyleSheets.removeElementAt(index);

                    unlinkStyleSheet(ss, index);

                    if (index == 0 && linkedStyleSheets.size() == 0) {

                        linkedStyleSheets = null;

                    }

                }

            }

        }

    }

    //

    // The following is used to import style sheets.

    //

    /**

     * Returns an array of the linked StyleSheets. Will return null

     * if there are no linked StyleSheets.

     *

     * @return an array of StyleSheets.

     * @since 1.3

     */

    public StyleSheet[] getStyleSheets() {

        StyleSheet[] retValue;

        synchronized(this) {

            if (linkedStyleSheets != null) {

                retValue = new StyleSheet[linkedStyleSheets.size()];

                linkedStyleSheets.copyInto(retValue);

            }

            else {

                retValue = null;

            }

        }

        return retValue;

    }

    /**

     * Imports a style sheet from <code>url</code>. The resulting rules

     * are directly added to the receiver. If you do not want the rules

     * to become part of the receiver, create a new StyleSheet and use

     * addStyleSheet to link it in.

     *

     * @param url an url

     * @since 1.3

     */

    public void importStyleSheet(URL url) {

        try {

            InputStream is;

            is = url.openStream();

            Reader r = new BufferedReader(new InputStreamReader(is));

            CssParser parser = new CssParser();

            parser.parse(url, r, false, true);

            r.close();

            is.close();

        } catch (Throwable e) {

            // on error we simply have no styles... the html

            // will look mighty wrong but still function.

        }

    }

    /**

     * Sets the base. All import statements that are relative, will be

     * relative to <code>base</code>.

     *

     * @param base a base.

     * @since 1.3

     */

    public void setBase(URL base) {

        this.base = base;

    }

    /**

     * Returns the base.

     *

     * @return the base.

     * @since 1.3

     */

    public URL getBase() {

        return base;

    }

    /**

     * Adds a CSS attribute to the given set.

     *

     * @param attr a set of attributes

     * @param key a CSS property