Text framework: Add TextListener in TextDocumentLayout...

... and invalidate based on TextChangedEvents. I am not yet sure whether
TextChangeEvent needs separate counts for removed and changed paragraphs.
It is most likely not yet correct and may either update too many paragraph
layouts or miss updating some at the end.

src/apps/haikudepot/textview/TextDocumentLayout.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2014, Stephan Aßmus <superstippi@gmx.de>.
+ * Copyright 2013-2015, Stephan Aßmus <superstippi@gmx.de>.
  * All rights reserved. Distributed under the terms of the MIT License.
  */
 
@@ -11,12 +11,40 @@
 #include <View.h>
 
 
+class LayoutTextListener : public TextListener {
+public:
+	LayoutTextListener(TextDocumentLayout* layout)
+		:
+		fLayout(layout)
+	{
+	}
+
+	virtual	void TextChanging(TextChangingEvent& event)
+	{
+	}
+
+	virtual	void TextChanged(const TextChangedEvent& event)
+	{
+		printf("TextChanged(%" B_PRIi32 ", %" B_PRIi32 ")\n",
+			event.FirstChangedParagraph(),
+			event.ChangedParagraphCount());
+		fLayout->InvalidateParagraphs(event.FirstChangedParagraph(),
+			event.ChangedParagraphCount());
+	}
+
+private:
+	TextDocumentLayout*	fLayout;
+};
+
+
+
 TextDocumentLayout::TextDocumentLayout()
 	:
 	fWidth(0.0f),
 	fLayoutValid(false),
 
 	fDocument(),
+	fTextListener(new(std::nothrow) LayoutTextListener(this), true),
 	fParagraphLayouts()
 {
 }
@@ -27,10 +55,11 @@ TextDocumentLayout::TextDocumentLayout(const TextDocumentRef& document)
 	fWidth(0.0f),
 	fLayoutValid(false),
 
-	fDocument(document),
+	fDocument(),
+	fTextListener(new(std::nothrow) LayoutTextListener(this), true),
 	fParagraphLayouts()
 {
-	_Init();
+	SetTextDocument(document);
 }
 
 
@@ -40,24 +69,35 @@ TextDocumentLayout::TextDocumentLayout(const TextDocumentLayout& other)
 	fLayoutValid(other.fLayoutValid),
 
 	fDocument(other.fDocument),
+	fTextListener(new(std::nothrow) LayoutTextListener(this), true),
 	fParagraphLayouts(other.fParagraphLayouts)
 {
+	if (fDocument.Get() != NULL)
+		fDocument->AddListener(fTextListener);
 }
 
 
 TextDocumentLayout::~TextDocumentLayout()
 {
+	SetTextDocument(NULL);
 }
 
 
 void
 TextDocumentLayout::SetTextDocument(const TextDocumentRef& document)
 {
-	if (fDocument != document) {
-		fDocument = document;
-		_Init();
-		fLayoutValid = false;
-	}
+	if (fDocument == document)
+		return;
+
+	if (fDocument.Get() != NULL)
+		fDocument->RemoveListener(fTextListener);
+
+	fDocument = document;
+	_Init();
+	fLayoutValid = false;
+
+	if (fDocument.Get() != NULL)
+		fDocument->AddListener(fTextListener);
 }
 
 
@@ -297,6 +337,9 @@ TextDocumentLayout::_Init()
 {
 	fParagraphLayouts.Clear();
 
+	if (fDocument.Get() == NULL)
+		return;
+
 	const ParagraphList& paragraphs = fDocument->Paragraphs();
 
 	int paragraphCount = paragraphs.CountItems();

src/apps/haikudepot/textview/TextDocumentLayout.h

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2014, Stephan Aßmus <superstippi@gmx.de>.
+ * Copyright 2013-2015, Stephan Aßmus <superstippi@gmx.de>.
  * All rights reserved. Distributed under the terms of the MIT License.
  */
 #ifndef TEXT_DOCUMENT_LAYOUT_H
@@ -124,6 +124,7 @@ class TextDocumentLayout : public BReferenceable {
 			bool				fLayoutValid;
 
 			TextDocumentRef		fDocument;
+			TextListenerRef		fTextListener;
 			ParagraphLayoutList	fParagraphLayouts;
 };