*
* For performance reasons, the linked list of tokens is reused after each
* line is tokenized. Therefore, the return value of markTokens
* should only be used for immediate painting. Notably, it cannot be
* cached.
*
* @author Slava Pestov
* @version $Id: TokenMarker.java,v 1.1 2005/04/09 02:30:37 benfry Exp $
*
* @see org.gjt.sp.jedit.syntax.Token
*/
public abstract class TokenMarker
{
/**
* A wrapper for the lower-level markTokensImpl method
* that is called to split a line up into tokens.
* @param line The line
* @param lineIndex The line number
*/
public Token markTokens(Segment line, int lineIndex)
{
if(lineIndex >= length)
{
throw new IllegalArgumentException("Tokenizing invalid line: "
+ lineIndex);
}
lastToken = null;
LineInfo info = lineInfo[lineIndex];
LineInfo prev;
if(lineIndex == 0)
prev = null;
else
prev = lineInfo[lineIndex - 1];
byte oldToken = info.token;
byte token = markTokensImpl(prev == null ?
Token.NULL : prev.token,line,lineIndex);
info.token = token;
/*
* This is a foul hack. It stops nextLineRequested
* from being cleared if the same line is marked twice.
*
* Why is this necessary? It's all JEditTextArea's fault.
* When something is inserted into the text, firing a
* document event, the insertUpdate() method shifts the
* caret (if necessary) by the amount inserted.
*
* All caret movement is handled by the select() method,
* which eventually pipes the new position to scrollTo()
* and calls repaint().
*
* Note that at this point in time, the new line hasn't
* yet been painted; the caret is moved first.
*
* scrollTo() calls offsetToX(), which tokenizes the line
* unless it is being called on the last line painted
* (in which case it uses the text area's painter cached
* token list). What scrollTo() does next is irrelevant.
*
* After scrollTo() has done it's job, repaint() is
* called, and eventually we end up in paintLine(), whose
* job is to paint the changed line. It, too, calls
* markTokens().
*
* The problem was that if the line started a multiline
* token, the first markTokens() (done in offsetToX())
* would set nextLineRequested (because the line end
* token had changed) but the second would clear it
* (because the line was the same that time) and therefore
* paintLine() would never know that it needed to repaint
* subsequent lines.
*
* This bug took me ages to track down, that's why I wrote
* all the relevant info down so that others wouldn't
* duplicate it.
*/
if(!(lastLine == lineIndex && nextLineRequested))
nextLineRequested = (oldToken != token);
lastLine = lineIndex;
addToken(0,Token.END);
return firstToken;
}
/**
* An abstract method that splits a line up into tokens. It
* should parse the line, and call addToken() to
* add syntax tokens to the token list. Then, it should return
* the initial token type for the next line.
*
* For example if the current line contains the start of a
* multiline comment that doesn't end on that line, this method
* should return the comment token type so that it continues on
* the next line.
*
* @param token The initial token type for this line
* @param line The line to be tokenized
* @param lineIndex The index of the line in the document,
* starting at 0
* @return The initial token type for the next line
*/
protected abstract byte markTokensImpl(byte token, Segment line,
int lineIndex);
/**
* Returns if the token marker supports tokens that span multiple
* lines. If this is true, the object using this token marker is
* required to pass all lines in the document to the
* markTokens() method (in turn).
*
* The default implementation returns true; it should be overridden
* to return false on simpler token markers for increased speed.
*/
public boolean supportsMultilineTokens()
{
return true;
}
/**
* Informs the token marker that lines have been inserted into
* the document. This inserts a gap in the lineInfo
* array.
* @param index The first line number
* @param lines The number of lines
*/
public void insertLines(int index, int lines)
{
if(lines <= 0)
return;
length += lines;
ensureCapacity(length);
int len = index + lines;
System.arraycopy(lineInfo,index,lineInfo,len,
lineInfo.length - len);
for(int i = index + lines - 1; i >= index; i--)
{
lineInfo[i] = new LineInfo();
}
}
/**
* Informs the token marker that line have been deleted from
* the document. This removes the lines in question from the
* lineInfo array.
* @param index The first line number
* @param lines The number of lines
*/
public void deleteLines(int index, int lines)
{
if (lines <= 0)
return;
int len = index + lines;
length -= lines;
System.arraycopy(lineInfo,len,lineInfo,
index,lineInfo.length - len);
}
/**
* Returns the number of lines in this token marker.
*/
public int getLineCount()
{
return length;
}
/**
* Returns true if the next line should be repainted. This
* will return true after a line has been tokenized that starts
* a multiline token that continues onto the next line.
*/
public boolean isNextLineRequested()
{
return nextLineRequested;
}
// protected members
/**
* The first token in the list. This should be used as the return
* value from markTokens().
*/
protected Token firstToken;
/**
* The last token in the list. New tokens are added here.
* This should be set to null before a new line is to be tokenized.
*/
protected Token lastToken;
/**
* An array for storing information about lines. It is enlarged and
* shrunk automatically by the insertLines() and
* deleteLines() methods.
*/
protected LineInfo[] lineInfo;
/**
* The number of lines in the model being tokenized. This can be
* less than the length of the lineInfo array.
*/
protected int length;
/**
* The last tokenized line.
*/
protected int lastLine;
/**
* True if the next line should be painted.
*/
protected boolean nextLineRequested;
/**
* Creates a new TokenMarker. This DOES NOT create
* a lineInfo array; an initial call to insertLines()
* does that.
*/
protected TokenMarker()
{
lastLine = -1;
}
/**
* Ensures that the lineInfo array can contain the
* specified index. This enlarges it if necessary. No action is
* taken if the array is large enough already.
*
* It should be unnecessary to call this under normal
* circumstances; insertLine() should take care of
* enlarging the line info array automatically.
*
* @param index The array index
*/
protected void ensureCapacity(int index)
{
if(lineInfo == null)
lineInfo = new LineInfo[index + 1];
else if(lineInfo.length <= index)
{
LineInfo[] lineInfoN = new LineInfo[(index + 1) * 2];
System.arraycopy(lineInfo,0,lineInfoN,0,
lineInfo.length);
lineInfo = lineInfoN;
}
}
/**
* Adds a token to the token list.
* @param length The length of the token
* @param id The id of the token
*/
protected void addToken(int length, byte id)
{
if(id >= Token.INTERNAL_FIRST && id <= Token.INTERNAL_LAST)
throw new InternalError("Invalid id: " + id);
if(length == 0 && id != Token.END)
return;
if(firstToken == null)
{
firstToken = new Token(length,id);
lastToken = firstToken;
}
else if(lastToken == null)
{
lastToken = firstToken;
firstToken.length = length;
firstToken.id = id;
}
else if(lastToken.next == null)
{
lastToken.next = new Token(length,id);
lastToken = lastToken.next;
}
else
{
lastToken = lastToken.next;
lastToken.length = length;
lastToken.id = id;
}
}
/**
* Inner class for storing information about tokenized lines.
*/
public class LineInfo
{
/**
* Creates a new LineInfo object with token = Token.NULL
* and obj = null.
*/
public LineInfo()
{
}
/**
* Creates a new LineInfo object with the specified
* parameters.
*/
public LineInfo(byte token, Object obj)
{
this.token = token;
this.obj = obj;
}
/**
* The id of the last token of the line.
*/
public byte token;
/**
* This is for use by the token marker implementations
* themselves. It can be used to store anything that
* is an object and that needs to exist on a per-line
* basis.
*/
public Object obj;
}
}