Make SharedBuffer in Resource non-discardable and remove PurgeableVector

third_party/WebKit/Source/platform/PurgeableVector.h

-/*
- * Copyright (C) 2014 Google Inc. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#ifndef PurgeableVector_h
-#define PurgeableVector_h
-
-#include "platform/PlatformExport.h"
-#include "wtf/Forward.h"
-#include "wtf/Noncopyable.h"
-#include "wtf/Vector.h"
-
-#include <memory>
-
-namespace base {
-class DiscardableMemory;
-}
-
-namespace blink {
-
-class WebProcessMemoryDump;
-
-// A simple vector implementation that supports purgeable memory.
-// TODO(hiroshige): PurgeableVector is about to be removed and some
-// functionality has already been removed https://crbug.com/603791.
-class PLATFORM_EXPORT PurgeableVector {
-    DISALLOW_NEW();
-    WTF_MAKE_NONCOPYABLE(PurgeableVector);
-public:
-    enum PurgeableOption {
-        NotPurgeable,
-        Purgeable,
-    };
-
-    PurgeableVector(PurgeableOption = Purgeable);
-
-    ~PurgeableVector();
-
-    void adopt(Vector<char>& other);
-
-    void append(const char* data, size_t length);
-
-    void grow(size_t);
-
-    void clear();
-
-    char* data();
-
-    size_t size() const;
-
-    // Note that this method should be used carefully since it may not use
-    // exponential growth internally. This means that repeated/invalid uses of
-    // it can result in O(N^2) append(). If you don't exactly know what you are
-    // doing then you should probably not call this method.
-    void reserveCapacity(size_t capacity);
-
-    void onMemoryDump(const String& dumpPrefix, WebProcessMemoryDump*) const;
-
-private:
-    enum PurgeableAllocationStrategy {
-        UseExactCapacity,
-        UseExponentialGrowth,
-    };
-
-    // Copies data from the discardable buffer to the vector and clears the
-    // discardable buffer.
-    void moveDataFromDiscardableToVector();
-
-    void clearDiscardable();
-
-    bool reservePurgeableCapacity(size_t capacity, PurgeableAllocationStrategy);
-
-    size_t adjustPurgeableCapacity(size_t capacity) const;
-
-    // Vector used when the instance is constructed without the purgeability
-    // hint or when discardable memory allocation fails.
-    // Note that there can't be data both in |m_vector| and
-    // |m_discardable|, i.e. only one of them is used at a given time.
-    Vector<char> m_vector;
-    std::unique_ptr<base::DiscardableMemory> m_discardable;
-    size_t m_discardableCapacity;
-    size_t m_discardableSize;
-    bool m_isPurgeable;
-};
-
-} // namespace blink
-
-#endif // PurgeableVector_h