From 5cb7a511dbdfc78a6fa5a7361df11420b08afb2b Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Fri, 10 May 2019 11:00:16 +0200
Subject: ui: somewhat aggressively cache icons

---
 ui/iconprovider.go | 92 +++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 71 insertions(+), 21 deletions(-)

(limited to 'ui/iconprovider.go')

diff --git a/ui/iconprovider.go b/ui/iconprovider.go
index e2647939..9f6cc433 100644
--- a/ui/iconprovider.go
+++ b/ui/iconprovider.go
@@ -12,29 +12,47 @@ import (
 	"golang.org/x/sys/windows"
 	"golang.zx2c4.com/wireguard/windows/service"
 	"path"
+	"syscall"
 )
 
-func iconWithOverlayForState(state service.TunnelState, size int) (*walk.Icon, error) {
-	wireguardIcon, err := walk.NewIconFromResourceWithSize("$wireguard.ico", walk.Size{size, size})
+type widthAndState struct {
+	width int
+	state service.TunnelState
+}
+
+type widthAndDllIdx struct {
+	width int
+	idx   int32
+	dll   string
+}
+
+var cachedOverlayIconsForWidthAndState = make(map[widthAndState]*walk.Icon)
+
+func iconWithOverlayForState(state service.TunnelState, size int) (icon *walk.Icon, err error) {
+	icon = cachedOverlayIconsForWidthAndState[widthAndState{size, state}]
+	if icon != nil {
+		return
+	}
+	wireguardIcon, err := loadLogoIcon(size)
 	if err != nil {
-		return nil, err
+		return
 	}
-	defer wireguardIcon.Dispose()
 	iconSize := wireguardIcon.Size()
 	bmp, err := walk.NewBitmapWithTransparentPixels(iconSize)
 	if err != nil {
-		return nil, err
+		return
 	}
 	defer bmp.Dispose()
 
 	canvas, err := walk.NewCanvasFromImage(bmp)
 	if err != nil {
-		return nil, err
+		return
 	}
 	defer canvas.Dispose()
 
-	if err := canvas.DrawImage(wireguardIcon, walk.Point{}); err != nil {
-		return nil, err
+	err = canvas.DrawImage(wireguardIcon, walk.Point{})
+	if err != nil {
+		return
 	}
 
 	w := int(float64(iconSize.Width) * 0.65)
@@ -42,44 +60,76 @@ func iconWithOverlayForState(state service.TunnelState, size int) (*walk.Icon, e
 	bounds := walk.Rectangle{iconSize.Width - w, iconSize.Height - h, w, h}
 	overlayIcon, err := iconForState(state, bounds.Width)
 	if err != nil {
-		return nil, err
+		return
 	}
 	defer overlayIcon.Dispose()
-	if err := canvas.DrawImageStretched(overlayIcon, bounds); err != nil {
-		return nil, err
+	err = canvas.DrawImageStretched(overlayIcon, bounds)
+	if err != nil {
+		return
 	}
 	canvas.Dispose()
 
-	icon, err := walk.NewIconFromBitmap(bmp)
-	if err != nil {
-		return nil, err
+	icon, err = walk.NewIconFromBitmap(bmp)
+	if err == nil {
+		cachedOverlayIconsForWidthAndState[widthAndState{size, state}] = icon
 	}
-	return icon, nil
+	return
 }
 
+var cachedIconsForWidthAndState = make(map[widthAndState]*walk.Icon)
+
 func iconForState(state service.TunnelState, size int) (icon *walk.Icon, err error) {
+	icon = cachedIconsForWidthAndState[widthAndState{size, state}]
+	if icon != nil {
+		return
+	}
 	switch state {
 	case service.TunnelStarted:
 		icon, err = loadSystemIcon("imageres", 101, size)
-
 	case service.TunnelStopped:
 		icon, err = walk.NewIconFromResourceWithSize("dot-gray.ico", walk.Size{size, size}) //TODO: replace with real icon
-
 	default:
 		icon, err = loadSystemIcon("shell32", 238, size) //TODO: this doesn't look that great overlayed on the app icon
 	}
+	if err == nil {
+		cachedIconsForWidthAndState[widthAndState{size, state}] = icon
+	}
 	return
 }
 
-func loadSystemIcon(dll string, index int32, size int) (*walk.Icon, error) {
+var cachedSystemIconsForWidthAndDllIdx = make(map[widthAndDllIdx]*walk.Icon)
+
+func loadSystemIcon(dll string, index int32, size int) (icon *walk.Icon, err error) {
+	icon = cachedSystemIconsForWidthAndDllIdx[widthAndDllIdx{size, index, dll}]
+	if icon != nil {
+		return
+	}
 	system32, err := windows.GetSystemDirectory()
 	if err != nil {
-		return nil, err
+		return
 	}
 	var hicon win.HICON
 	ret := win.SHDefExtractIcon(windows.StringToUTF16Ptr(path.Join(system32, dll+".dll")), index, 0, &hicon, nil, uint32(size))
 	if ret != 0 {
-		return nil, fmt.Errorf("Unable to find icon %d of %s due to error %d", index, dll, ret)
+		return nil, fmt.Errorf("Unable to find icon %d of %s: %v", index, dll, syscall.Errno(ret))
+	}
+	icon, err = walk.NewIconFromHICON(hicon)
+	if err == nil {
+		cachedSystemIconsForWidthAndDllIdx[widthAndDllIdx{size, index, dll}] = icon
+	}
+	return
+}
+
+var cachedLogoIconsForWidth = make(map[int]*walk.Icon)
+
+func loadLogoIcon(size int) (icon *walk.Icon, err error) {
+	icon = cachedLogoIconsForWidth[size]
+	if icon != nil {
+		return
+	}
+	icon, err = walk.NewIconFromResourceWithSize("$wireguard.ico", walk.Size{size, size})
+	if err == nil {
+		cachedLogoIconsForWidth[size] = icon
 	}
-	return walk.NewIconFromHICON(hicon)
+	return
 }
-- 
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