Local salient image storage for enhanced bookmark experiment.

chrome/browser/bookmarks/enhanced/image_store_ios.mm

+// Copyright 2014 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.
+#include "chrome/browser/bookmarks/enhanced/image_store_ios.h"
+
+#import <UIKit/UIKit.h>
+
+#include "base/mac/scoped_cftyperef.h"
+#include "base/mac/scoped_nsobject.h"
+
+namespace {
+// An implementation of RefCountedMemory, where the bytes are stored in a
+// NSData. This class assumes the NSData is non mutable to avoid a copy.
+class RefCountedNSDataMemory : public base::RefCountedMemory {
+ public:
+  explicit RefCountedNSDataMemory(NSData* memory) : data_([memory retain]) {}
+
+  virtual const unsigned char* front() const OVERRIDE {
+    return reinterpret_cast<const unsigned char*>([data_ bytes]);
+  }
+
+  virtual size_t size() const OVERRIDE {
+    return [data_ length];
+  }
+
+private:
+  virtual ~RefCountedNSDataMemory() {}
+
+  base::scoped_nsobject<NSData> data_;
+  DISALLOW_COPY_AND_ASSIGN(RefCountedNSDataMemory);
+};
+}  // namespace
+
+namespace image_store_ios {
+
+// Encodes the UIImage representation of a gfx::Image.
+const scoped_refptr<base::RefCountedMemory> bytesForImage(gfx::Image image) {
+  DCHECK(image.HasRepresentation(gfx::Image::kImageRepCocoaTouch));
+  return scoped_refptr<RefCountedNSDataMemory>(new RefCountedNSDataMemory(
+      [NSKeyedArchiver archivedDataWithRootObject:image.ToUIImage()]));
+}
+
+// Decodes the UIImage in the bytes and returns a gfx::Image.
+gfx::Image imageForBytes(const scoped_refptr<base::RefCountedMemory>& data) {
+  return gfx::Image([[NSKeyedUnarchiver unarchiveObjectWithData:
+      [NSData dataWithBytes:data->front() length:data->size()]] retain]);
+}
+
+// Generates a gfx::Image with a random UIImage representation. Used for tests.
+gfx::Image generateRandomUIImage(gfx::Size& size, float scale) {
+  UIGraphicsBeginImageContextWithOptions(CGSizeMake(size.width(),
+                                                    size.height()),
+                                         YES,  // opaque.
+                                         scale);
+
+  // Create the gradient's colors.
+  CGFloat locations[] = { 0.0, 1.0 };
+  CGFloat components[] = { rand()/CGFloat(RAND_MAX),  // Start color r
+                           rand()/CGFloat(RAND_MAX),  // g
+                           rand()/CGFloat(RAND_MAX),  // b
+                           1.0,                       // Alpha
+                           rand()/CGFloat(RAND_MAX),  // End color r
+                           rand()/CGFloat(RAND_MAX),  // g
+                           rand()/CGFloat(RAND_MAX),  // b
+                           1.0 };                     // Alpha
+  CGPoint center = CGPointMake(size.width() / 2, size.height() / 2);
+  CGFloat radius = MIN(size.width(), size.height());
+
+  base::ScopedCFTypeRef<CGColorSpaceRef>
+      colorspace(CGColorSpaceCreateDeviceRGB());
+  base::ScopedCFTypeRef<CGGradientRef>
+      gradient(CGGradientCreateWithColorComponents(colorspace,
+                                                   components,
+                                                   locations,
+                                                   arraysize(locations)));
+  CGContextDrawRadialGradient(UIGraphicsGetCurrentContext(),
+                              gradient,
+                              center,
+                              0,
+                              center,
+                              radius,
+                              kCGGradientDrawsAfterEndLocation);
+  UIImage* image = UIGraphicsGetImageFromCurrentImageContext();
+  UIGraphicsEndImageContext();
+  return gfx::Image([image retain]);
+}
+}  // namespace image_store_ios