Always call the class methods to save/restore contexts.

If the current context was ever nil, sending a "restore" message would be a no-op and would likely leave an out-of-scope context as current.

BUG=90140
TEST=repeatedly select items in an open file dialog in column mode; no crash

Review URL: http://codereview.chromium.org/7572031

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@95611 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/ui/cocoa/bookmarks/bookmark_bar_toolbar_view.mm

@@ -56,8 +56,7 @@ const CGFloat kBorderRadius = 3.0;
   if (!themeProvider)
     return;
 
-  NSGraphicsContext* context = [NSGraphicsContext currentContext];
-  gfx::ScopedNSGraphicsContextSaveGState scopedGState(context);
+  gfx::ScopedNSGraphicsContextSaveGState scopedGState;
 
   // Draw the background.
   {
@@ -103,8 +102,9 @@ const CGFloat kBorderRadius = 3.0;
 
   // Fade in/out the background.
   {
-    gfx::ScopedNSGraphicsContextSaveGState bgScopedState(context);
+    gfx::ScopedNSGraphicsContextSaveGState bgScopedState;
     [border setClip];
+    NSGraphicsContext* context = [NSGraphicsContext currentContext];
     CGContextRef cgContext = (CGContextRef)[context graphicsPort];
     CGContextBeginTransparencyLayer(cgContext, NULL);
     CGContextSetAlpha(cgContext, 1 - morph);

chrome/browser/ui/cocoa/download/download_item_cell.mm

@@ -406,14 +406,14 @@ const int kInterruptedAnimationDuration = 2.5;
           nil];
   NSPoint secondaryPos =
       NSMakePoint(innerFrame.origin.x + kTextPosLeft, kSecondaryTextPosTop);
+
+  gfx::ScopedNSGraphicsContextSaveGState contextSave;
   NSGraphicsContext* nsContext = [NSGraphicsContext currentContext];
   CGContextRef cgContext = (CGContextRef)[nsContext graphicsPort];
-  [nsContext saveGraphicsState];
   [nsContext setCompositingOperation:NSCompositeSourceOver];
   CGContextSetAlpha(cgContext, statusAlpha_);
   [secondaryText drawAtPoint:secondaryPos
               withAttributes:secondaryTextAttributes];
-  [nsContext restoreGraphicsState];
 }
 
 - (void)drawWithFrame:(NSRect)cellFrame inView:(NSView*)controlView {
@@ -579,8 +579,7 @@ const int kInterruptedAnimationDuration = 2.5;
   [triangle lineToPoint:p3];
   [triangle closePath];
 
-  NSGraphicsContext* context = [NSGraphicsContext currentContext];
-  gfx::ScopedNSGraphicsContextSaveGState scopedGState(context);
+  gfx::ScopedNSGraphicsContextSaveGState scopedGState;
 
   scoped_nsobject<NSShadow> shadow([[NSShadow alloc] init]);
   [shadow.get() setShadowColor:[NSColor whiteColor]];

chrome/browser/ui/cocoa/find_bar/find_bar_view.mm

@@ -64,8 +64,8 @@ CGFloat kCurveSize = 8;
         controlPoint2:NSMakePoint(midRight2.x, topLeft.y)];
 
   {
+    gfx::ScopedNSGraphicsContextSaveGState scopedGState;
     NSGraphicsContext* context = [NSGraphicsContext currentContext];
-    gfx::ScopedNSGraphicsContextSaveGState scopedGState(context);
     [path addClip];
 
     // Set the pattern phase

chrome/browser/ui/cocoa/tabs/tab_view.mm

@@ -251,8 +251,8 @@ const CGFloat kRapidCloseDist = 2.5;
 - (void)drawRect:(NSRect)dirtyRect {
   const CGFloat lineWidth = [self cr_lineWidth];
 
+  gfx::ScopedNSGraphicsContextSaveGState scopedGState;
   NSGraphicsContext* context = [NSGraphicsContext currentContext];
-  gfx::ScopedNSGraphicsContextSaveGState scopedGState(context);
 
   ThemeService* themeProvider =
       static_cast<ThemeService*>([[self window] themeProvider]);
@@ -288,7 +288,8 @@ const CGFloat kRapidCloseDist = 2.5;
       [[[self window] backgroundColor] set];
       [path fill];
 
-      gfx::ScopedNSGraphicsContextSaveGState drawBackgroundState(context);
+      gfx::ScopedNSGraphicsContextSaveGState drawBackgroundState;
+      NSGraphicsContext* context = [NSGraphicsContext currentContext];
       CGContextRef cgContext =
           static_cast<CGContextRef>([context graphicsPort]);
       CGContextBeginTransparencyLayer(cgContext, 0);
@@ -299,55 +300,6 @@ const CGFloat kRapidCloseDist = 2.5;
     }
   }
 
-  [context saveGraphicsState];
-  [path addClip];
-
-  // Use the same overlay for the selected state and for hover and alert glows;
-  // for the selected state, it's fully opaque.
-  CGFloat hoverAlpha = [self hoverAlpha];
-  CGFloat alertAlpha = [self alertAlpha];
-  if (selected || hoverAlpha > 0 || alertAlpha > 0) {
-    // Draw the selected background / glow overlay.
-    gfx::ScopedNSGraphicsContextSaveGState drawHoverState(context);
-    CGContextRef cgContext = static_cast<CGContextRef>([context graphicsPort]);
-    CGContextBeginTransparencyLayer(cgContext, 0);
-    if (!selected) {
-      // The alert glow overlay is like the selected state but at most at most
-      // 80% opaque. The hover glow brings up the overlay's opacity at most 50%.
-      CGFloat backgroundAlpha = 0.8 * alertAlpha;
-      backgroundAlpha += (1 - backgroundAlpha) * 0.5 * hoverAlpha;
-      CGContextSetAlpha(cgContext, backgroundAlpha);
-    }
-    [path addClip];
-    {
-      gfx::ScopedNSGraphicsContextSaveGState drawBackgroundState(context);
-      [super drawBackgroundWithOpaque:NO];
-    }
-
-    // Draw a mouse hover gradient for the default themes.
-    if (!selected && hoverAlpha > 0) {
-      if (themeProvider && !hasBackgroundImage) {
-        scoped_nsobject<NSGradient> glow([NSGradient alloc]);
-        [glow initWithStartingColor:[NSColor colorWithCalibratedWhite:1.0
-                                        alpha:1.0 * hoverAlpha]
-                        endingColor:[NSColor colorWithCalibratedWhite:1.0
-                                                                alpha:0.0]];
-
-        NSPoint point = hoverPoint_;
-        point.y = NSHeight(rect);
-        [glow drawFromCenter:point
-                      radius:0.0
-                    toCenter:point
-                      radius:NSWidth(rect) / 3.0
-                     options:NSGradientDrawsBeforeStartingLocation];
-
-        [glow drawInBezierPath:path relativeCenterPosition:hoverPoint_];
-      }
-    }
-
-    CGContextEndTransparencyLayer(cgContext);
-  }
-
   BOOL active = [[self window] isKeyWindow] || [[self window] isMainWindow];
   CGFloat borderAlpha = selected ? (active ? 0.3 : 0.2) : 0.2;
   NSColor* borderColor = [NSColor colorWithDeviceWhite:0.0 alpha:borderAlpha];
@@ -356,35 +308,87 @@ const CGFloat kRapidCloseDist = 2.5;
           ThemeService::COLOR_TOOLBAR_BEZEL :
           ThemeService::COLOR_TOOLBAR, true) : nil;
 
-  // Draw the top inner highlight within the tab if using the default theme.
-  if (themeProvider && themeProvider->UsingDefaultTheme()) {
-    NSAffineTransform* highlightTransform = [NSAffineTransform transform];
-    [highlightTransform translateXBy:lineWidth yBy:-lineWidth];
-    if (selected) {
-      scoped_nsobject<NSBezierPath> highlightPath([path copy]);
-      [highlightPath transformUsingAffineTransform:highlightTransform];
-      [highlightColor setStroke];
-      [highlightPath setLineWidth:lineWidth];
-      [highlightPath stroke];
-      highlightTransform = [NSAffineTransform transform];
-      [highlightTransform translateXBy:-2 * lineWidth yBy:0.0];
-      [highlightPath transformUsingAffineTransform:highlightTransform];
-      [highlightPath stroke];
-    } else {
-      NSBezierPath* topHighlightPath =
-          [self topHighlightBezierPathForRect:[self bounds]];
-      [topHighlightPath transformUsingAffineTransform:highlightTransform];
-      [highlightColor setStroke];
-      [topHighlightPath setLineWidth:lineWidth];
-      [topHighlightPath stroke];
+  {
+    gfx::ScopedNSGraphicsContextSaveGState contextSave;
+    [path addClip];
+
+    // Use the same overlay for the selected state and for hover and alert
+    // glows; for the selected state, it's fully opaque.
+    CGFloat hoverAlpha = [self hoverAlpha];
+    CGFloat alertAlpha = [self alertAlpha];
+    if (selected || hoverAlpha > 0 || alertAlpha > 0) {
+      // Draw the selected background / glow overlay.
+      gfx::ScopedNSGraphicsContextSaveGState drawHoverState;
+      NSGraphicsContext* context = [NSGraphicsContext currentContext];
+      CGContextRef cgContext =
+          static_cast<CGContextRef>([context graphicsPort]);
+      CGContextBeginTransparencyLayer(cgContext, 0);
+      if (!selected) {
+        // The alert glow overlay is like the selected state but at most at most
+        // 80% opaque. The hover glow brings up the overlay's opacity at most
+        // 50%.
+        CGFloat backgroundAlpha = 0.8 * alertAlpha;
+        backgroundAlpha += (1 - backgroundAlpha) * 0.5 * hoverAlpha;
+        CGContextSetAlpha(cgContext, backgroundAlpha);
+      }
+      [path addClip];
+      {
+        gfx::ScopedNSGraphicsContextSaveGState drawBackgroundState;
+        [super drawBackgroundWithOpaque:NO];
+      }
+
+      // Draw a mouse hover gradient for the default themes.
+      if (!selected && hoverAlpha > 0) {
+        if (themeProvider && !hasBackgroundImage) {
+          scoped_nsobject<NSGradient> glow([NSGradient alloc]);
+          [glow initWithStartingColor:[NSColor colorWithCalibratedWhite:1.0
+                                          alpha:1.0 * hoverAlpha]
+                          endingColor:[NSColor colorWithCalibratedWhite:1.0
+                                                                  alpha:0.0]];
+
+          NSPoint point = hoverPoint_;
+          point.y = NSHeight(rect);
+          [glow drawFromCenter:point
+                        radius:0.0
+                      toCenter:point
+                        radius:NSWidth(rect) / 3.0
+                       options:NSGradientDrawsBeforeStartingLocation];
+
+          [glow drawInBezierPath:path relativeCenterPosition:hoverPoint_];
+        }
+      }
+
+      CGContextEndTransparencyLayer(cgContext);
     }
-  }
 
-  [context restoreGraphicsState];
+    // Draw the top inner highlight within the tab if using the default theme.
+    if (themeProvider && themeProvider->UsingDefaultTheme()) {
+      NSAffineTransform* highlightTransform = [NSAffineTransform transform];
+      [highlightTransform translateXBy:lineWidth yBy:-lineWidth];
+      if (selected) {
+        scoped_nsobject<NSBezierPath> highlightPath([path copy]);
+        [highlightPath transformUsingAffineTransform:highlightTransform];
+        [highlightColor setStroke];
+        [highlightPath setLineWidth:lineWidth];
+        [highlightPath stroke];
+        highlightTransform = [NSAffineTransform transform];
+        [highlightTransform translateXBy:-2 * lineWidth yBy:0.0];
+        [highlightPath transformUsingAffineTransform:highlightTransform];
+        [highlightPath stroke];
+      } else {
+        NSBezierPath* topHighlightPath =
+            [self topHighlightBezierPathForRect:[self bounds]];
+        [topHighlightPath transformUsingAffineTransform:highlightTransform];
+        [highlightColor setStroke];
+        [topHighlightPath setLineWidth:lineWidth];
+        [topHighlightPath stroke];
+      }
+    }
+  }
 
   // Draw the top stroke.
   {
-    gfx::ScopedNSGraphicsContextSaveGState drawBorderState(context);
+    gfx::ScopedNSGraphicsContextSaveGState drawBorderState;
     [borderColor set];
     [path setLineWidth:lineWidth];
     [path stroke];

chrome/default_plugin/plugin_impl_mac.mm

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -17,6 +17,7 @@
 #include "ui/base/l10n/l10n_util_mac.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/image/image.h"
+#include "ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h"
 #include "unicode/locid.h"
 #include "webkit/glue/webkit_glue.h"
 #include "webkit/plugins/npapi/default_plugin_shared.h"
@@ -139,7 +140,7 @@ void PluginInstallerImpl::DownloadCancelled() {
 }
 
 int16 PluginInstallerImpl::OnDrawRect(CGContextRef context, CGRect dirty_rect) {
-  [NSGraphicsContext saveGraphicsState];
+  gfx::ScopedNSGraphicsContextSaveGState scoped_state;
   NSGraphicsContext* ns_context = [NSGraphicsContext
       graphicsContextWithGraphicsPort:context flipped:YES];
   [NSGraphicsContext setCurrentContext:ns_context];
@@ -183,7 +184,6 @@ int16 PluginInstallerImpl::OnDrawRect(CGContextRef context, CGRect dirty_rect) {
   label_point = NSMakePoint(roundf(label_point.x), roundf(label_point.y));
   [command_ drawAtPoint:label_point withAttributes:attributes];
 
-  [NSGraphicsContext restoreGraphicsState];
   return 1;
 }
 

ui/base/clipboard/clipboard_mac.mm

@@ -16,6 +16,7 @@
 #import "third_party/mozilla/NSPasteboard+Utils.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/gfx/canvas_skia.h"
+#include "ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h"
 #include "ui/gfx/size.h"
 
 namespace ui {
@@ -248,6 +249,7 @@ SkBitmap Clipboard::ReadImage(Buffer buffer) const {
   scoped_nsobject<NSImage> image(
       [[NSImage alloc] initWithPasteboard:GetPasteboard()]);
   if (image.get()) {
+    gfx::ScopedNSGraphicsContextSaveGState scoped_state;
     [image setFlipped:YES];
     int width = [image size].width;
     int height = [image size].height;
@@ -262,7 +264,6 @@ SkBitmap Clipboard::ReadImage(Buffer buffer) const {
              fromRect:NSZeroRect
             operation:NSCompositeCopy
              fraction:1.0];
-    [NSGraphicsContext restoreGraphicsState];
     return canvas.ExtractBitmap();
   }
   return SkBitmap();

ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h

@@ -4,23 +4,27 @@
 
 #ifndef UI_GFX_SCOPED_NS_GRAPHICS_CONTEXT_SAVE_GSTATE_MAC_H_
 #define UI_GFX_SCOPED_NS_GRAPHICS_CONTEXT_SAVE_GSTATE_MAC_H_
+#pragma once
 
-#include "ui/ui_api.h"
 #include "base/basictypes.h"
-#include "base/memory/scoped_nsobject.h"
+#include "ui/ui_api.h"
 
+#if defined(__OBJC__)
 @class NSGraphicsContext;
+#else
+class NSGraphicsContext;
+#endif
 
 namespace gfx {
 
+// A class to save/restore the state of the current context.
 class UI_API ScopedNSGraphicsContextSaveGState {
  public:
-  // If |context| is nil, it will use the |+currentContext|.
-  explicit ScopedNSGraphicsContextSaveGState(NSGraphicsContext* context = nil);
+  ScopedNSGraphicsContextSaveGState();
   ~ScopedNSGraphicsContextSaveGState();
 
  private:
-  scoped_nsobject<NSGraphicsContext> context_;
+  NSGraphicsContext* context_;  // weak
 
   DISALLOW_COPY_AND_ASSIGN(ScopedNSGraphicsContextSaveGState);
 };

ui/gfx/scoped_ns_graphics_context_save_gstate_mac.mm

@@ -4,19 +4,20 @@
 
 #include "ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h"
 
-#include <AppKit/AppKit.h>
+#import <AppKit/AppKit.h>
+
+#include "base/logging.h"
 
 namespace gfx {
 
-ScopedNSGraphicsContextSaveGState::ScopedNSGraphicsContextSaveGState(
-    NSGraphicsContext* context) : context_([context retain]) {
-  if (!context_)
-    context_.reset([[NSGraphicsContext currentContext] retain]);
-  [context_ saveGraphicsState];
+ScopedNSGraphicsContextSaveGState::ScopedNSGraphicsContextSaveGState()
+    : context_([NSGraphicsContext currentContext]) {
+  [NSGraphicsContext saveGraphicsState];
 }
 
 ScopedNSGraphicsContextSaveGState::~ScopedNSGraphicsContextSaveGState() {
-  [context_ restoreGraphicsState];
+  [NSGraphicsContext restoreGraphicsState];
+  DCHECK_EQ(context_, [NSGraphicsContext currentContext]);
 }
 
 }  // namespace gfx