/bundles/plugins-trunk/XML/xml/SideKickTagHighlight.java

/*
 * SideKickTagHighlight.java
 * :tabSize=8:indentSize=8:noTabs=false:
 * :folding=explicit:collapseFolds=1:
 *
 * Copyright (c) 2011 Eric Le Lay
 *
 * The XML plugin is licensed under the GNU General Public License, with
 * the following exception:
 *
 * "Permission is granted to link this code with software released under
 * the Apache license version 1.1, for example used by the Xerces XML
 * parser package."
 */
package xml;

//{{{ Imports
import java.io.Reader;
import org.gjt.sp.jedit.GUIUtilities;
import org.gjt.sp.jedit.textarea.StructureMatcher;
import org.gjt.sp.jedit.textarea.TextArea;
import org.gjt.sp.jedit.textarea.JEditTextArea;
import org.gjt.sp.jedit.Buffer;
import org.gjt.sp.jedit.buffer.JEditBuffer;
import org.gjt.sp.util.Log;
import sidekick.SideKickActions;
import sidekick.SideKickParsedData;
import sidekick.IAsset;
import sidekick.util.ElementUtil;
import xml.parser.javacc.*;
import xml.parser.XmlTag;
//}}}
/**
 * StructureMatcher finding the matching tag (open/close).
 * It uses 
 *  - first the current SideKick tree to go to the open tag very fase
 *  - then xml.parser.javacc.TagParser, which will really parse this part of the buffer to get tag boundaries
 * */
public class SideKickTagHighlight implements StructureMatcher
{
	//{{{ getMatch() method
	public StructureMatcher.Match getMatch(TextArea textArea)
	{
		long startTime = System.currentTimeMillis();
		
		if(XmlPlugin.isDelegated(textArea)) {
			return null;
		}

		int caret = textArea.getCaretPosition();
		SideKickParsedData parsedData = XmlParsedData.getParsedData(((JEditTextArea)textArea).getView(), false);

		if(parsedData == null)
		{
			return null;
		}
		else
		{
			TagParser.Tag tag = null;
			IAsset asset = parsedData.getAssetAtOffset(caret);
			if(asset != null)
			{
				/* use the XML javacc parser to parse the start tag.
				 * If the caret is inside the start tag,
				 * then look for the '<' from the end of the region,
				 * to get easily the end tag (there is nothing to check for in the
				 * end tag : no quoted attributes and so on).
				 * On the contrary, when looking for '>' from the start of the region,
				 * one has to take care of '>' in attribute values, so it's better to simply
				 * use the javacc parser.
				 * */
				JEditBuffer b =  textArea.getBuffer();
				int max = b.getLength();
				if(Debug.DEBUG_TAG_HIGHLIGHT)System.err.println("asset is at "+asset.getStart().getOffset()+" - "+asset.getEnd().getOffset());
				int sA = asset.getStart().getOffset();
				int lA = asset.getEnd().getOffset()-sA;
				if(sA < 0 || sA > max){
					return null;
				}
				if(lA < 0 || sA+lA > max){
					return null;
				}
				CharSequence toParse = b.getSegment(sA,lA);
				int line = b.getLineOfOffset(sA);
				int col = b.getVirtualWidth(line, sA-b.getLineStartOffset(line))+1;
				if(Debug.DEBUG_TAG_HIGHLIGHT)System.err.println("line="+line+",col="+col);
				Reader r = new CharSequenceReader(toParse);
				XmlParser parser = new XmlParser(r,line+1,
					col);
				// set tab size so that ElementUtil.createStartPosition()
				// will compute a correct position, taking virtual columns
				// into account
				parser.setTabSize( b.getTabSize() );
				try{
					XmlDocument.XmlElement startTag = parser.Tag();
					// don't highlight self-closing tags : it flickers annoyingly when typing
					if(startTag instanceof XmlDocument.Tag && ((XmlDocument.Tag)startTag).emptyTag)return null;
					
					if(Debug.DEBUG_TAG_HIGHLIGHT)System.err.println("startL="+startTag.getStartLocation()+",endL="+startTag.getEndLocation());
					// FIXME: switch back to ElementUtil when fixed
					// int start = ElementUtil.createStartPosition((Buffer)textArea.getBuffer(),startTag).getOffset();
					// int end= ElementUtil.createEndPosition((Buffer)textArea.getBuffer(),startTag).getOffset();
					int start = xml.ElementUtil.createOffset((Buffer)textArea.getBuffer(),startTag.getStartLocation());
					int end=  xml.ElementUtil.createOffset((Buffer)textArea.getBuffer(),startTag.getEndLocation());
					tag = new TagParser.Tag(
						start,
						end);
					if(Debug.DEBUG_TAG_HIGHLIGHT)System.err.println("start="+start+",end="+end);

					int startEndTag = start;
					for(int i=toParse.length()-2;i>0;i--){
						if(toParse.charAt(i) == '<'){
							startEndTag = start + i;
							break;
						}else if(toParse.charAt(i) == '>'){
							return null;
						}
					}
					if(caret > end && caret < startEndTag)
					{
						if(Debug.DEBUG_TAG_HIGHLIGHT)System.err.println("not in end ("+startEndTag+","+(start + toParse.length())+") nor start tag");
						return null;
					}
					else if(caret <= end)
					{
						if(Debug.DEBUG_TAG_HIGHLIGHT)System.err.println("inside start tag");
						/* if the caret is inside start tag */
						tag.start = startEndTag;
						tag.end = start + toParse.length();
					}
					tag.startLine = textArea.getLineOfOffset(tag.start);
					tag.endLine = textArea.getLineOfOffset(tag.end);
					tag.matcher = this;
					
				}catch(ParseException pe){
					Log.log(Log.DEBUG, SideKickTagHighlight.class, "error parsing during matching tag highlight");
				}
			}
			Log.log(Log.DEBUG, SideKickTagHighlight.class, "highlighting matching tag has taken "+(System.currentTimeMillis()-startTime)+"ms");
			return tag;
		}
	} //}}}

	//{{{ selectMatch() method
	/**
	 * Selects from the caret to the matching structure element (if there is
	 * one, otherwise the behavior of this method is undefined).
	 * @since jEdit 4.2pre3
	 */
	public void selectMatch(TextArea textArea)
	{
		SideKickActions.selectAsset(GUIUtilities.getView(textArea));
	} //}}}
}