gecko-dev/dom/xhr/XMLHttpRequestString.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_dom_XMLHttpRequestString_h
#define mozilla_dom_XMLHttpRequestString_h
#include "mozilla/Mutex.h"
#include "nsString.h"
namespace mozilla {
namespace dom {
class DOMString;
class XMLHttpRequestStringBuffer;
class XMLHttpRequestStringSnapshot;
class XMLHttpRequestStringWriterHelper;
class XMLHttpRequestStringSnapshotReaderHelper;
// We want to avoid the dup of strings when XHR in workers has access to
// responseText for events dispatched during the loading state. For this reason
// we use this class, able to create snapshots of the current size of itself
// without making extra copies.
class XMLHttpRequestString final
{
friend class XMLHttpRequestStringWriterHelper;
public:
XMLHttpRequestString();
~XMLHttpRequestString();
void Truncate();
uint32_t Length() const;
void Append(const nsAString& aString);
// This method should be called only when the string is really needed because
// it can cause the duplication of the strings in case the loading of the XHR
// is not completed yet.
MOZ_MUST_USE bool GetAsString(nsAString& aString) const;
size_t SizeOfThis(MallocSizeOf aMallocSizeOf) const;
const char16_t* Data() const;
bool IsEmpty() const;
void CreateSnapshot(XMLHttpRequestStringSnapshot& aSnapshot);
private:
XMLHttpRequestString(const XMLHttpRequestString&) = delete;
XMLHttpRequestString& operator=(const XMLHttpRequestString&) = delete;
XMLHttpRequestString& operator=(const XMLHttpRequestString&&) = delete;
RefPtr<XMLHttpRequestStringBuffer> mBuffer;
};
// This class locks the buffer and allows the callee to write data into it.
class MOZ_STACK_CLASS XMLHttpRequestStringWriterHelper final
{
public:
explicit XMLHttpRequestStringWriterHelper(XMLHttpRequestString& aString);
bool
AddCapacity(int32_t aCapacity);
char16_t*
EndOfExistingData();
void
AddLength(int32_t aLength);
private:
XMLHttpRequestStringWriterHelper(const XMLHttpRequestStringWriterHelper&) = delete;
XMLHttpRequestStringWriterHelper& operator=(const XMLHttpRequestStringWriterHelper&) = delete;
XMLHttpRequestStringWriterHelper& operator=(const XMLHttpRequestStringWriterHelper&&) = delete;
RefPtr<XMLHttpRequestStringBuffer> mBuffer;
MutexAutoLock mLock;
};
// This class is the internal XMLHttpRequestStringBuffer of the
// XMLHttpRequestString plus the current length. GetAsString will return the
// string with that particular length also if the XMLHttpRequestStringBuffer is
// grown in the meantime.
class XMLHttpRequestStringSnapshot final
{
friend class XMLHttpRequestStringBuffer;
friend class XMLHttpRequestStringSnapshotReaderHelper;
public:
XMLHttpRequestStringSnapshot();
~XMLHttpRequestStringSnapshot();
XMLHttpRequestStringSnapshot& operator=(const XMLHttpRequestStringSnapshot&);
void Reset()
{
ResetInternal(false /* isVoid */);
}
void SetVoid()
{
ResetInternal(true /* isVoid */);
}
bool IsVoid() const
{
return mVoid;
}
bool IsEmpty() const
{
return !mLength;
}
MOZ_MUST_USE bool GetAsString(DOMString& aString) const;
private:
XMLHttpRequestStringSnapshot(const XMLHttpRequestStringSnapshot&) = delete;
XMLHttpRequestStringSnapshot& operator=(const XMLHttpRequestStringSnapshot&&) = delete;
void Set(XMLHttpRequestStringBuffer* aBuffer, uint32_t aLength);
void ResetInternal(bool aIsVoid);
RefPtr<XMLHttpRequestStringBuffer> mBuffer;
uint32_t mLength;
bool mVoid;
};
// This class locks the buffer and allows the callee to read data from it.
class MOZ_STACK_CLASS XMLHttpRequestStringSnapshotReaderHelper final
{
public:
explicit XMLHttpRequestStringSnapshotReaderHelper(XMLHttpRequestStringSnapshot& aSnapshot);
const char16_t*
Buffer() const;
uint32_t
Length() const;
private:
XMLHttpRequestStringSnapshotReaderHelper(const XMLHttpRequestStringSnapshotReaderHelper&) = delete;
XMLHttpRequestStringSnapshotReaderHelper& operator=(const XMLHttpRequestStringSnapshotReaderHelper&) = delete;
XMLHttpRequestStringSnapshotReaderHelper& operator=(const XMLHttpRequestStringSnapshotReaderHelper&&) = delete;
RefPtr<XMLHttpRequestStringBuffer> mBuffer;
MutexAutoLock mLock;
};
} // dom namespace
} // mozilla namespace
#endif // mozilla_dom_XMLHttpRequestString_h