Patch from Stephan to improve folding.

Added a few consts.

1 files changed, 51 insertions, 30 deletions

diff --git a/src/LexPython.cxx b/src/LexPython.cxx
index ae5836b0b..221859035 100644
--- a/src/LexPython.cxx
+++ b/src/LexPython.cxx
@@ -270,14 +270,15 @@ static bool IsQuoteLine(int line, Accessor &styler) {
 	return ((style == SCE_P_TRIPLE) || (style== SCE_P_TRIPLEDOUBLE));
 }
 
+
 static void FoldPyDoc(unsigned int startPos, int length, int /*initStyle - unused*/,
 					WordList *[], Accessor &styler) {
-	int maxPos = startPos + length;
-	int maxLines = styler.GetLine(maxPos-1);
-						
-	bool foldComment = styler.GetPropertyInt("fold.comment.python");
-	bool foldQuotes = styler.GetPropertyInt("fold.quotes.python");
-
+	const int maxPos = startPos + length;
+	const int maxLines = styler.GetLine(maxPos-1);             // Requested last line
+	const int docLines = styler.GetLine(styler.Length() - 1);  // Available last line
+	const bool foldComment = styler.GetPropertyInt("fold.comment.python");
+	const bool foldQuotes = styler.GetPropertyInt("fold.quotes.python");
+	
 	// Backtrack to previous non-blank line so we can determine indent level
 	// for any white space lines (needed esp. within triple quoted strings)
 	// and so we can fix any preceding fold level (which is why we go back
@@ -295,8 +296,8 @@ static void FoldPyDoc(unsigned int startPos, int length, int /*initStyle - unuse
 	}
 	int indentCurrentLevel = indentCurrent & SC_FOLDLEVELNUMBERMASK;
 	
+	// Set up initial loop state
 	startPos = styler.LineStart(lineCurrent);
-	// Set up initial state
 	int prev_state = SCE_P_DEFAULT & 31;
 	if (lineCurrent >= 1)
 		prev_state = styler.StyleAt(startPos-1) & 31;
@@ -306,21 +307,27 @@ static void FoldPyDoc(unsigned int startPos, int length, int /*initStyle - unuse
 		prevComment = foldComment && IsCommentLine(lineCurrent - 1, styler);
 
 	// Process all characters to end of requested range or end of any triple quote
-	// or comment that hangs over the end of the range
-	while ((lineCurrent <= maxLines) || prevQuote || prevComment) {
+	// or comment that hangs over the end of the range.  Cap processing in all cases
+	// to end of document (in case of unclosed quote or comment at end).
+	while ((lineCurrent <= docLines) && ((lineCurrent <= maxLines) || prevQuote || prevComment)) {
 
 		// Gather info
 		int lev = indentCurrent;
 		int lineNext = lineCurrent + 1;
-		int style = styler.StyleAt(styler.LineStart(lineNext)) & 31;
-		int indentNext = styler.IndentAmount(lineNext, &spaceFlags, NULL);
-		int quote = foldQuotes && ((style == SCE_P_TRIPLE) || (style== SCE_P_TRIPLEDOUBLE));
-		int quote_start = (quote && !prevQuote);
-		int quote_continue = (quote && prevQuote);
-		int comment = foldComment && IsCommentLine(lineCurrent, styler);
-		int comment_start = (comment && !prevComment && 
+		int indentNext = indentCurrent;
+		int quote = false;
+		if (lineNext <= docLines) {
+			// Information about next line is only available if not at end of document
+			indentNext = styler.IndentAmount(lineNext, &spaceFlags, NULL);
+			int style = styler.StyleAt(styler.LineStart(lineNext)) & 31;
+			quote = foldQuotes && ((style == SCE_P_TRIPLE) || (style== SCE_P_TRIPLEDOUBLE));
+		}
+		const int quote_start = (quote && !prevQuote);
+		const int quote_continue = (quote && prevQuote);
+		const int comment = foldComment && IsCommentLine(lineCurrent, styler);
+		const int comment_start = (comment && !prevComment && (lineNext <= docLines) &&
 			IsCommentLine(lineNext, styler) && (lev > SC_FOLDLEVELBASE));
-		int comment_continue = (comment && prevComment);
+		const int comment_continue = (comment && prevComment);
 		if ((!quote || !prevQuote) && !comment)
 			indentCurrentLevel = indentCurrent & SC_FOLDLEVELNUMBERMASK;
 		if (quote)
@@ -343,22 +350,35 @@ static void FoldPyDoc(unsigned int startPos, int length, int /*initStyle - unuse
 		}
 
 		// Skip past any blank lines for next indent level info; we skip also comments
-		// starting in column 0 which effectively folds them into surrounding code
-		// rather than screwing up folding.  Then set indent level on the lines
-		// we skipped to be same as maximum of current and next indent.  This approach
-		// does a reasonable job of collapsing white space into surrounding code
-		// without getting confused by white space at the start of an indented level.
+		// starting in column 0 which effectively folds them into surrounding code rather
+		// than screwing up folding.
+		const int saveIndentNext = indentNext;
 		while (!quote &&
-		       ((indentNext & SC_FOLDLEVELWHITEFLAG) || styler[styler.LineStart(lineNext)] == '#') &&
-		       (lineNext < maxLines)) {
-			int level = Platform::Maximum(indentCurrent, indentNext);
-			if (indentNext & SC_FOLDLEVELWHITEFLAG)
-				level = SC_FOLDLEVELWHITEFLAG | indentCurrentLevel;
-			styler.SetLevel(lineNext, level);
+		       (lineNext < docLines) &&
+		       ((indentNext & SC_FOLDLEVELWHITEFLAG) || 
+		        (lineNext <= docLines && styler[styler.LineStart(lineNext)] == '#'))) {
+
 			lineNext++;
 			indentNext = styler.IndentAmount(lineNext, &spaceFlags, NULL);
 		}
 
+		// Next compute max indent level of current line and next non-blank line.
+		// This is the level to which we set all the intervening blank or comment lines.
+		const int skip_level = Platform::Maximum(indentCurrentLevel,
+		                                   indentNext & SC_FOLDLEVELNUMBERMASK);
+		
+		// Now set all the indent levels on the lines we skipped
+		int skipLine = lineCurrent + 1;
+		int skipIndentNext = saveIndentNext;
+		while (skipLine < lineNext) {
+			int skipLineLevel = skip_level;
+			if (skipIndentNext & SC_FOLDLEVELWHITEFLAG)
+				skipLineLevel = SC_FOLDLEVELWHITEFLAG | skipLineLevel;
+			styler.SetLevel(skipLine, skipLineLevel);
+			skipLine++;
+			skipIndentNext = styler.IndentAmount(skipLine, &spaceFlags, NULL);
+		}
+		
 		// Set fold header on non-quote/non-comment line
 		if (!quote && !comment && !(indentCurrent & SC_FOLDLEVELWHITEFLAG) ) {
 			if ((indentCurrent & SC_FOLDLEVELNUMBERMASK) < (indentNext & SC_FOLDLEVELNUMBERMASK))
@@ -375,8 +395,9 @@ static void FoldPyDoc(unsigned int startPos, int length, int /*initStyle - unuse
 		lineCurrent = lineNext;
 	}
 
-	// Make sure last line indent level is set too
-	styler.SetLevel(lineCurrent, indentCurrent);
+	// NOTE: Cannot set level of last line here because indentCurrent doesn't have
+	// header flag set; the loop above is crafted to take care of this case!
+	//styler.SetLevel(lineCurrent, indentCurrent);
 }
 
 LexerModule lmPython(SCLEX_PYTHON, ColourisePyDoc, "python", FoldPyDoc);