Backport: Remove CGContextRef field in QuartzTextLayout as it is only used in draw method

where it can easily be provided. Retaining a CGContextRef in QuartzTextLayout
could lead to it being used after being invalidated.

Backport of changeset 6963:a8774d6100a6.

2 files changed, 8 insertions, 20 deletions

diff --git a/cocoa/PlatCocoa.mm b/cocoa/PlatCocoa.mm
index fe1873ffa..b517a7e6a 100644
--- a/cocoa/PlatCocoa.mm
+++ b/cocoa/PlatCocoa.mm
@@ -134,7 +134,7 @@ SurfaceImpl::SurfaceImpl()
   y = 0;
   gc = NULL;
 
-  textLayout.reset(new QuartzTextLayout(nullptr));
+  textLayout.reset(new QuartzTextLayout());
   codePage = 0;
   verticalDeviceResolution = 0;
 
@@ -156,7 +156,6 @@ SurfaceImpl::~SurfaceImpl()
 
 void SurfaceImpl::Clear()
 {
-  textLayout->setContext(nullptr);
   if (bitmapData)
   {
     bitmapData.reset();
@@ -206,7 +205,6 @@ void SurfaceImpl::Init(SurfaceID sid, WindowID)
   Release();
   gc = static_cast<CGContextRef>(sid);
   CGContextSetLineWidth(gc, 1.0);
-  textLayout->setContext(gc);
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -244,7 +242,6 @@ void SurfaceImpl::InitPixMap(int width, int height, Surface* surface_, WindowID
     // and we have no use for the bitmap without the context
     bitmapData.reset();
   }
-  textLayout->setContext (gc);
 
   // the context retains the color space, so we can release it
   CGColorSpaceRelease(colorSpace);
@@ -920,7 +917,7 @@ void SurfaceImpl::DrawTextTransparent(PRectangle rc, Font &font_, XYPOSITION yba
 	CGColorRelease(color);
 
 	textLayout->setText(s, len, encoding, *style);
-	textLayout->draw(rc.left, ybase);
+	textLayout->draw(gc, rc.left, ybase);
 }
 
 //--------------------------------------------------------------------------------------------------
diff --git a/cocoa/QuartzTextLayout.h b/cocoa/QuartzTextLayout.h
index 0f813f301..f2387dd9b 100644
--- a/cocoa/QuartzTextLayout.h
+++ b/cocoa/QuartzTextLayout.h
@@ -19,13 +19,9 @@
 class QuartzTextLayout
 {
 public:
-    /** Create a text layout for drawing on the specified context. */
-    explicit QuartzTextLayout( CGContextRef context )
+    /** Create a text layout for drawing. */
+    QuartzTextLayout() : mString(NULL), mLine(NULL), stringLength(0)
     {
-		mString = NULL;
-		mLine = NULL;
-		stringLength = 0;
-        setContext(context);
     }
 
     ~QuartzTextLayout()
@@ -63,12 +59,13 @@ public:
 		CFRelease( str );
     }
 
-    /** Draw the text layout into the current CGContext at the specified position.
+    /** Draw the text layout into a CGContext at the specified position.
+	* @param gc The CGContext in which to draw the text.
     * @param x The x axis position to draw the baseline in the current CGContext.
     * @param y The y axis position to draw the baseline in the current CGContext. */
-    void draw( float x, float y )
+    void draw( CGContextRef gc, float x, float y )
     {
-		if (mLine == NULL)
+		if (!mLine)
 			return;
 
 		::CGContextSetTextMatrix(gc, CGAffineTransformMakeScale(1.0, -1.0));
@@ -96,13 +93,7 @@ public:
 	    return stringLength;
     }
 
-    inline void setContext (CGContextRef context)
-    {
-        gc = context;
-    }
-
 private:
-    CGContextRef gc;
 	CFAttributedStringRef mString;
 	CTLineRef mLine;
 	CFIndex stringLength;