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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libjava/classpath/gnu/javax/swing/text/html/css/CSSParser.java | |
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Diffstat (limited to 'libjava/classpath/gnu/javax/swing/text/html/css/CSSParser.java')
-rw-r--r-- | libjava/classpath/gnu/javax/swing/text/html/css/CSSParser.java | 503 |
1 files changed, 503 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/javax/swing/text/html/css/CSSParser.java b/libjava/classpath/gnu/javax/swing/text/html/css/CSSParser.java new file mode 100644 index 000000000..4be315e37 --- /dev/null +++ b/libjava/classpath/gnu/javax/swing/text/html/css/CSSParser.java @@ -0,0 +1,503 @@ +/* CSSParser.java -- A parser for CSS stylesheets + Copyright (C) 2006 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + + +package gnu.javax.swing.text.html.css; + +import java.io.BufferedInputStream; +import java.io.File; +import java.io.FileInputStream; +import java.io.IOException; +import java.io.InputStream; +import java.io.InputStreamReader; +import java.io.Reader; +import java.util.StringTokenizer; + +/** + * A parser for CSS stylesheets. + * + * This parser is based on the simple CSS grammar describe in + * + * http://www.w3.org/TR/CSS21/syndata.html . + * + * @author Roman Kennke (kennke@aicas.com) + */ +// TODO: Maybe use more restrictive grammar: +// http://www.w3.org/TR/CSS21/grammar.html#q1 +public class CSSParser +{ + + /** + * The scanner used to read the input streams into more usable tokens. + */ + private CSSScanner scanner; + + /** + * The parser callback. + */ + private CSSParserCallback callback; + + /** + * One lookahead token. + */ + private int lookahead; + + /** + * The parse error. + */ + private String error; + + /** + * Creates a new CSSParser that parses the specified input. + * + * @param in the source to parse + */ + public CSSParser(Reader in, CSSParserCallback cb) + { + scanner = new CSSScanner(in); + callback = cb; + lookahead = -1; + } + + /** + * Parses the input source specified in the constructor. + * + * @throws IOException if an IO or parse error occurs + */ + public void parse() + throws IOException + { + boolean success = parseStylesheet(); + if (! success) + { + throw new CSSParserException(error); + } + } + + /** + * Parses a stylesheet. + * + * @return <code>true</code> if the stylesheet could be parsed successfully, + * <code>false</code> otherwise + * + * @throws IOException if an IO or parse error occurs + */ + private boolean parseStylesheet() + throws IOException + { + int token = peekToken(); + while (token != CSSScanner.EOF && (token == CSSScanner.CDC + || token == CSSScanner.CDO || token == CSSScanner.S + || parseStatement())) + { + if (token == CSSScanner.CDC || token == CSSScanner.CDO + || token == CSSScanner.S) + readToken(); + token = peekToken(); + } + // Last token must be EOF for valid stylesheets, I'd think. + return token == CSSScanner.EOF; + } + + /** + * Parses a CSS statement. + * @return <code>true</code> if the stylesheet could be parsed successfully, + * <code>false</code> otherwise + * + * @throws IOException if an IO or parse error occurs + */ + private boolean parseStatement() + throws IOException + { + return parseRuleset() || parseAtRule(); + } + + /** + * Parses a CSS rule set. + * + * @return <code>true</code> if the ruleset could be parsed successfully, + * <code>false</code> otherwise + * + * @throws IOException if an IO or parse error occurs + */ + private boolean parseRuleset() + throws IOException + { + StringBuilder selector = new StringBuilder(); + parseSelector(selector); + StringTokenizer selSplitter = + new StringTokenizer(selector.toString(), ","); + Selector[] sels = new Selector[selSplitter.countTokens()]; + for (int i = 0; selSplitter.hasMoreTokens(); i++) + { + String sel = selSplitter.nextToken().trim(); + sels[i] = new Selector(sel); + } + callback.startStatement(sels); + // Read any number of whitespace. + int token; + do + { + token = readToken(); + } while (token == CSSScanner.S); + boolean ret = true; + + if (token == CSSScanner.CURLY_LEFT) + { + // Read any number of whitespace. + do + { + token = readToken(); + } while (token == CSSScanner.S); + lookahead = token; + + // Maybe read declaration. + boolean decl = parseDeclaration(); + token = peekToken(); + while (token == CSSScanner.SEMICOLON) + { + readToken(); // Read the semicolon. + // Read any number of whitespace. + do + { + token = readToken(); + } while (token == CSSScanner.S); + lookahead = token; + + // Maybe read declaration. + parseDeclaration(); + token = peekToken(); + } + if (token != CSSScanner.CURLY_RIGHT) + { + error = "Expected right curly brace"; + ret = false; + } + else + { + readToken(); + // Read any number of whitespace. + do + { + token = readToken(); + } while (token == CSSScanner.S); + lookahead = token; + callback.endStatement(); + } + } + else + { + ret = false; + error = "Expected left curly brace"; + } + return ret; + } + + /** + * Parses a CSS declaration. + * + * @return <code>true</code> if the ruleset could be parsed successfully, + * <code>false</code> otherwise + * + * @throws IOException if an IO or parse error occurs + */ + private boolean parseDeclaration() + throws IOException + { + // Maybe fetch one DELIM. + int token = readToken(); + if (token == CSSScanner.DELIM) + token = readToken(); + + boolean ret = true; + + // Parse property + String property = null; + if (token == CSSScanner.IDENT) + { + property = new String(scanner.parseBuffer, 0, scanner.tokenEnd); + // Read any number of whitespace. + do + { + token = readToken(); + } while (token == CSSScanner.S); + + // Read ':'. + if (token == CSSScanner.DELIM && scanner.parseBuffer[0] == ':') + { + // Read any number of whitespace. + do + { + token = readToken(); + } while (token == CSSScanner.S); + lookahead = token; + + StringBuilder value = new StringBuilder(); + if (parseValue(value)) + { + callback.declaration(property, value.toString().trim()); + } + else + { + ret = false; + error = "Error while reading the property value"; + } + } + else + { + ret = false; + error = "Expected colon to separate property and value"; + } + + } + else + { + lookahead = token; + ret = false; + error = "Expected IDENT token for property"; + } + return ret; + } + + /** + * Parses a property value. + * + * @param s the string builder to read the value into + * + * @return <code>true</code> if the ruleset could be parsed successfully, + * <code>false</code> otherwise + * + * @throws IOException if an IO or parse error occurs + */ + private boolean parseValue(StringBuilder s) + throws IOException + { + // FIXME: Handle block and ATKEYWORD. + boolean success = parseAny(s); + while (parseAny(s)) + ; + + return success; + } + + /** + * Parses a selector. + * + * @param sel the string buffer to put the selector into + * + * @return <code>true</code> if the ruleset could be parsed successfully, + * <code>false</code> otherwise + * + * @throws IOException if an IO or parse error occurs + */ + private boolean parseSelector(StringBuilder sel) + throws IOException + { + // At least one any needs to be parsed. + boolean ret = parseAny(sel); + if (ret) + { + while (parseAny(sel)) + ; + } + return ret; + } + + /** + * Parses the any rule. If s is not null, then the contents of the + * tokens is appended verbatim. + * + * @param s the string builder to append to + * + * @return <code>true</code> if the ruleset could be parsed successfully, + * <code>false</code> otherwise + * + * @throws IOException if an IO or parse error occurs + */ + private boolean parseAny(StringBuilder s) + throws IOException + { + int token = peekToken(); + boolean ret = false; + if (token == CSSScanner.IDENT || token == CSSScanner.NUMBER + || token == CSSScanner.PERCENTAGE || token == CSSScanner.DIMENSION + || token == CSSScanner.STRING || token == CSSScanner.DELIM + || token == CSSScanner.URI || token == CSSScanner.HASH + || token == CSSScanner.UNICODE_RANGE || token == CSSScanner.INCLUDES + || token == CSSScanner.DASHMATCH) + { + if (s != null) + s.append(scanner.parseBuffer, 0, scanner.tokenEnd); + readToken(); + ret = true; + } + else if (token == CSSScanner.FUNCTION) + System.err.println("Implement parseAny for FUNCTION"); + else if (token == CSSScanner.PAREN_LEFT) + System.err.println("Implement parseAny for ("); + else if (token == CSSScanner.BRACE_LEFT) + System.err.println("Implement parseAny for ["); + + // Parse any following whitespace too. + token = peekToken(); + while (token == CSSScanner.S) + { + if (s != null) + s.append(scanner.parseBuffer, 0, scanner.tokenEnd); + readToken(); + token = peekToken(); + } + return ret; + } + + /** + * Parses a CSS at-rule. + * + * @return <code>true</code> if the at-rule could be parsed successfully, + * <code>false</code> otherwise + * + * @throws IOException if an IO or parse error occurs + */ + private boolean parseAtRule() + throws IOException + { + // FIXME: Implement. + return false; + } + + /** + * Reads the next token, and skips the comments. + * + * @return the next non-comment token + */ + private int readToken() + throws IOException + { + int token; + if (lookahead == -1) + { + do + { + token = scanner.nextToken(); + } while (token == CSSScanner.COMMENT); + } + else + { + token = lookahead; + lookahead = -1; + } + return token; + } + + /** + * Returns the next token to be read, without really reading it. The next + * call to readToken() will return the same token again. + * + * @return the next token to be read, without really reading it + */ + private int peekToken() + throws IOException + { + int token; + if (lookahead == -1) + { + do + { + token = scanner.nextToken(); + } while (token == CSSScanner.COMMENT); + lookahead = token; + } + else + token = lookahead; + return token; + } + + /** + * For testing, we read in the default.css in javax/swing/text/html + * + * @param args + */ + public static void main(String[] args) + { + try + { + InputStream in; + if (args.length > 0) + { + File file = new File(args[0]); + in = new FileInputStream(file); + } + else + { + String name = "/javax/swing/text/html/default.css"; + in = CSSScanner.class.getResourceAsStream(name); + } + BufferedInputStream bin = new BufferedInputStream(in); + InputStreamReader r = new InputStreamReader(bin); + CSSParserCallback cb = new CSSParserCallback() + { + public void startStatement(Selector[] selector) + { + System.out.print("startStatement: "); + for (int i = 0; i < selector.length; i++) + { + System.out.print(selector[i]); + if (i < selector.length - 1) + System.out.print(','); + else + System.out.println(); + } + } + public void endStatement() + { + System.out.println("endStatement"); + } + public void declaration(String property, String value) + { + System.out.println("declaration: " + property + ", " + value); + } + }; + CSSParser p = new CSSParser(r, cb); + p.parse(); + } + catch (IOException ex) + { + ex.printStackTrace(); + } + } + +} |