HaikuDepot : Performance for Package List Updates

Performance improvements for the application updating
lists of packages when the user is operating with the
locale set to Russian.

fixes #14513

Change-Id: I1e2514a2afbd43503ac0edfe280a856411738026
Reviewed-on: https://review.haiku-os.org/612
Reviewed-by: waddlesplash <[email protected]>

src/apps/haikudepot/ui/MainWindow.cpp

@@ -936,6 +936,9 @@ MainWindow::_RefreshPackageList(bool force)
 	if (fSinglePackageMode)
 		return;
 
+	if (Logger::IsDebugEnabled())
+		printf("will refresh the package list\n");
+
 	BPackageRoster roster;
 	BStringList repositoryNames;
 
@@ -1221,6 +1224,9 @@ MainWindow::_RefreshPackageList(bool force)
 		printf("Unknown exception occurred while resolving system "
 			"dependencies.\n");
 	}
+
+	if (Logger::IsDebugEnabled())
+		printf("did refresh the package list\n");
 }
 
 

src/apps/haikudepot/ui/PackageListView.cpp

@@ -1,4 +1,5 @@
 /*
+ * Copyright 2018, Andrew Lindesay, <[email protected]>.
  * Copyright 2017, Julian Harnath, <[email protected]>.
  * Copyright 2015, Axel Dörfler, <[email protected]>.
  * Copyright 2013-2014, Stephan Aßmus <[email protected]>.
@@ -663,12 +664,16 @@ public:
 		SetViewUIColor(B_PANEL_BACKGROUND_COLOR);
 		SetLowUIColor(ViewUIColor());
 		SetHighUIColor(LowUIColor(), B_DARKEN_4_TINT);
+
+		// constantly calculating the size is expensive so here a sensible
+		// upper limit on the number of packages is arbitrarily chosen.
+		fMinSize = BSize(StringWidth(_DeriveLabel(999999)) + 10,
+			B_H_SCROLL_BAR_HEIGHT);
 	}
 
 	virtual BSize MinSize()
 	{
-		BString label(_GetLabel());
+		return fMinSize;
-		return BSize(StringWidth(label) + 10, B_H_SCROLL_BAR_HEIGHT);
 	}
 
 	virtual BSize PreferredSize()
@@ -685,13 +690,11 @@ public:
 	{
 		FillRect(updateRect, B_SOLID_LOW);
 
-		BString label(_GetLabel());
-
 		font_height fontHeight;
 		GetFontHeight(&fontHeight);
 
 		BRect bounds(Bounds());
-		float width = StringWidth(label);
+		float width = StringWidth(fLabel);
 
 		BPoint offset;
 		offset.x = bounds.left + (bounds.Width() - width) / 2.0f;
@@ -699,32 +702,38 @@ public:
 			- (fontHeight.ascent + fontHeight.descent)) / 2.0f
 			+ fontHeight.ascent;
 
-		DrawString(label, offset);
+		DrawString(fLabel, offset);
 	}
 
 	void SetItemCount(int32 count)
 	{
 		if (count == fItemCount)
 			return;
-		BSize minSize = MinSize();
 		fItemCount = count;
-		if (minSize != MinSize())
+		fLabel = _DeriveLabel(fItemCount);
-			InvalidateLayout();
 		Invalidate();
 	}
 
 private:
-	BString _GetLabel() const
+
+/*! This method is hit quite often when the list of packages in the
+    table-view are updated.  Derivation of the plural for some
+    languages such as Russian can be slow so this method should be
+    called sparingly.
+*/
+
+	BString _DeriveLabel(int32 count) const
 	{
 		static BStringFormat format(B_TRANSLATE("{0, plural, "
 			"one{# item} other{# items}}"));
-
 		BString label;
-		format.Format(label, fItemCount);
+		format.Format(label, count);
 		return label;
 	}
 
 	int32		fItemCount;
+	BString		fLabel;
+	BSize		fMinSize;
 };