Modify AsyncResourceHandler to use a single shared memory buffer (in ring

content/browser/renderer_host/resource_buffer_unittest.cc

+// Copyright (c) 2012 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 "content/browser/renderer_host/resource_buffer.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace content {
+
+TEST(ResourceBufferTest, BasicAllocations) {
+  scoped_refptr<ResourceBuffer> buf = new ResourceBuffer();
+  EXPECT_TRUE(buf->Initialize(100, 5, 10));
+  EXPECT_TRUE(buf->CanAllocate());
+
+  // First allocation
+  {
+    int size;
+    char* ptr = buf->Allocate(&size);
+    EXPECT_TRUE(ptr);
+    EXPECT_EQ(10, size);
+    EXPECT_TRUE(buf->CanAllocate());
+
+    EXPECT_EQ(0, buf->GetLastAllocationOffset());
+
+    buf->ShrinkLastAllocation(2);  // Less than our min allocation size.
+    EXPECT_EQ(0, buf->GetLastAllocationOffset());
+    EXPECT_TRUE(buf->CanAllocate());
+  }
+
+  // Second allocation
+  {
+    int size;
+    char* ptr = buf->Allocate(&size);
+    EXPECT_TRUE(ptr);
+    EXPECT_EQ(10, size);
+    EXPECT_TRUE(buf->CanAllocate());
+
+    EXPECT_EQ(5, buf->GetLastAllocationOffset());
+
+    buf->ShrinkLastAllocation(4);
+    EXPECT_EQ(5, buf->GetLastAllocationOffset());
+
+    EXPECT_TRUE(buf->CanAllocate());
+  }
+}
+
+TEST(ResourceBufferTest, AllocateAndRecycle) {
+  scoped_refptr<ResourceBuffer> buf = new ResourceBuffer();
+  EXPECT_TRUE(buf->Initialize(100, 5, 10));
+
+  int size;
+
+  buf->Allocate(&size);
+  EXPECT_EQ(0, buf->GetLastAllocationOffset());
+
+  buf->RecycleLeastRecentlyAllocated();
+
+  // Offset should again be 0.
+  buf->Allocate(&size);
+  EXPECT_EQ(0, buf->GetLastAllocationOffset());
+}
+
+TEST(ResourceBufferTest, WrapAround) {
+  scoped_refptr<ResourceBuffer> buf = new ResourceBuffer();
+  EXPECT_TRUE(buf->Initialize(20, 10, 10));
+
+  int size;
+
+  buf->Allocate(&size);
+  EXPECT_EQ(10, size);
+
+  buf->Allocate(&size);
+  EXPECT_EQ(10, size);
+
+  // Create hole at the beginnning.  Next allocation should go there.
+  buf->RecycleLeastRecentlyAllocated();
+
+  buf->Allocate(&size);
+  EXPECT_EQ(10, size);
+
+  EXPECT_EQ(0, buf->GetLastAllocationOffset());
+}
+
+TEST(ResourceBufferTest, WrapAround2) {
+  scoped_refptr<ResourceBuffer> buf = new ResourceBuffer();
+  EXPECT_TRUE(buf->Initialize(30, 10, 10));
+
+  int size;
+
+  buf->Allocate(&size);
+  EXPECT_EQ(10, size);
+
+  buf->Allocate(&size);
+  EXPECT_EQ(10, size);
+
+  buf->Allocate(&size);
+  EXPECT_EQ(10, size);
+
+  EXPECT_FALSE(buf->CanAllocate());
+
+  // Create holes at first and second slots.
+  buf->RecycleLeastRecentlyAllocated();
+  buf->RecycleLeastRecentlyAllocated();
+
+  EXPECT_TRUE(buf->CanAllocate());
+
+  buf->Allocate(&size);
+  EXPECT_EQ(10, size);
+  EXPECT_EQ(0, buf->GetLastAllocationOffset());
+
+  buf->Allocate(&size);
+  EXPECT_EQ(10, size);
+  EXPECT_EQ(10, buf->GetLastAllocationOffset());
+
+  EXPECT_FALSE(buf->CanAllocate());
+}
+
+TEST(ResourceBufferTest, Full) {
+  scoped_refptr<ResourceBuffer> buf = new ResourceBuffer();
+  EXPECT_TRUE(buf->Initialize(20, 10, 10));
+
+  int size;
+  buf->Allocate(&size);
+  EXPECT_EQ(10, size);
+
+  buf->Allocate(&size);
+  EXPECT_EQ(10, size);
+
+  // Full.
+  EXPECT_FALSE(buf->CanAllocate());
+
+  // Still full, even if there is a small hole at the end.
+  buf->ShrinkLastAllocation(5);
+  EXPECT_FALSE(buf->CanAllocate());
+}
+
+}  // namespace content