Source/WebKit/Platform/IPC/Encoder.cpp

/*
 * Copyright (C) 2010 Apple 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:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS 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 APPLE INC. OR ITS 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.
 */

#include "config.h"
#include "Encoder.h"

#include "DataReference.h"
#include "MessageFlags.h"
#include <algorithm>
#include <stdio.h>

#if OS(DARWIN)
#include <sys/mman.h>
#endif

namespace IPC {

static const uint8_t defaultMessageFlags = 0;

template <typename T>
static inline bool allocBuffer(T*& buffer, size_t size)
{
#if OS(DARWIN)
    buffer = static_cast<T*>(mmap(0, size, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0));
    return buffer != MAP_FAILED;
#else
    buffer = static_cast<T*>(fastMalloc(size));
    return !!buffer;
#endif
}

static inline void freeBuffer(void* addr, size_t size)
{
#if OS(DARWIN)
    munmap(addr, size);
#else
    UNUSED_PARAM(size);
    fastFree(addr);
#endif
}

Encoder::Encoder(StringReference messageReceiverName, StringReference messageName, uint64_t destinationID)
    : m_messageReceiverName(messageReceiverName)
    , m_messageName(messageName)
    , m_destinationID(destinationID)
    , m_buffer(m_inlineBuffer)
    , m_bufferPointer(m_inlineBuffer)
    , m_bufferSize(0)
    , m_bufferCapacity(sizeof(m_inlineBuffer))
{
    encodeHeader();
}

Encoder::~Encoder()
{
    if (m_buffer != m_inlineBuffer)
        freeBuffer(m_buffer, m_bufferCapacity);
    // FIXME: We need to dispose of the attachments in cases of failure.
}

bool Encoder::isSyncMessage() const
{
    return *buffer() & SyncMessage;
}

ShouldDispatchWhenWaitingForSyncReply Encoder::shouldDispatchMessageWhenWaitingForSyncReply() const
{
    if (*buffer() & DispatchMessageWhenWaitingForSyncReply)
        return ShouldDispatchWhenWaitingForSyncReply::Yes;
    if (*buffer() & DispatchMessageWhenWaitingForUnboundedSyncReply)
        return ShouldDispatchWhenWaitingForSyncReply::YesDuringUnboundedIPC;
    return ShouldDispatchWhenWaitingForSyncReply::No;
}

void Encoder::setIsSyncMessage(bool isSyncMessage)
{
    if (isSyncMessage)
        *buffer() |= SyncMessage;
    else
        *buffer() &= ~SyncMessage;
}

void Encoder::setShouldDispatchMessageWhenWaitingForSyncReply(ShouldDispatchWhenWaitingForSyncReply shouldDispatchWhenWaitingForSyncReply)
{
    switch (shouldDispatchWhenWaitingForSyncReply) {
    case ShouldDispatchWhenWaitingForSyncReply::No:
        *buffer() &= ~(DispatchMessageWhenWaitingForSyncReply | DispatchMessageWhenWaitingForUnboundedSyncReply);
        break;
    case ShouldDispatchWhenWaitingForSyncReply::Yes:
        *buffer() |= DispatchMessageWhenWaitingForSyncReply;
        *buffer() &= ~DispatchMessageWhenWaitingForUnboundedSyncReply;
        break;
    case ShouldDispatchWhenWaitingForSyncReply::YesDuringUnboundedIPC:
        *buffer() |= DispatchMessageWhenWaitingForUnboundedSyncReply;
        *buffer() &= ~DispatchMessageWhenWaitingForSyncReply;
        break;
    }
}

void Encoder::setFullySynchronousModeForTesting()
{
    *buffer() |= UseFullySynchronousModeForTesting;
}

void Encoder::wrapForTesting(std::unique_ptr<Encoder> original)
{
    ASSERT(isSyncMessage());
    ASSERT(!original->isSyncMessage());

    original->setShouldDispatchMessageWhenWaitingForSyncReply(ShouldDispatchWhenWaitingForSyncReply::Yes);

    encodeVariableLengthByteArray(DataReference(original->buffer(), original->bufferSize()));

    Vector<Attachment> attachments = original->releaseAttachments();
    reserve(attachments.size());
    for (Attachment& attachment : attachments)
        addAttachment(WTFMove(attachment));
}

static inline size_t roundUpToAlignment(size_t value, unsigned alignment)
{
    return ((value + alignment - 1) / alignment) * alignment;
}

void Encoder::reserve(size_t size)
{
    if (size <= m_bufferCapacity)
        return;

    size_t newCapacity = roundUpToAlignment(m_bufferCapacity * 2, 4096);
    while (newCapacity < size)
        newCapacity *= 2;

    uint8_t* newBuffer;
    if (!allocBuffer(newBuffer, newCapacity))
        CRASH();

    memcpy(newBuffer, m_buffer, m_bufferSize);

    if (m_buffer != m_inlineBuffer)
        freeBuffer(m_buffer, m_bufferCapacity);

    m_buffer = newBuffer;
    m_bufferCapacity = newCapacity;
}

void Encoder::encodeHeader()
{
    ASSERT(!m_messageReceiverName.isEmpty());

    *this << defaultMessageFlags;
    *this << m_messageReceiverName;
    *this << m_messageName;
    *this << m_destinationID;
}

uint8_t* Encoder::grow(unsigned alignment, size_t size)
{
    size_t alignedSize = roundUpToAlignment(m_bufferSize, alignment);
    reserve(alignedSize + size);

    std::memset(m_buffer + m_bufferSize, 0, alignedSize - m_bufferSize);

    m_bufferSize = alignedSize + size;
    m_bufferPointer = m_buffer + alignedSize + size;
    
    return m_buffer + alignedSize;
}

void Encoder::encodeFixedLengthData(const uint8_t* data, size_t size, unsigned alignment)
{
    ASSERT(!(reinterpret_cast<uintptr_t>(data) % alignment));

    uint8_t* buffer = grow(alignment, size);
    memcpy(buffer, data, size);
}

void Encoder::encodeVariableLengthByteArray(const DataReference& dataReference)
{
    encode(static_cast<uint64_t>(dataReference.size()));
    encodeFixedLengthData(dataReference.data(), dataReference.size(), 1);
}

template<typename Type>
static void copyValueToBuffer(Type value, uint8_t* bufferPosition)
{
    memcpy(bufferPosition, &value, sizeof(Type));
}

void Encoder::encode(bool n)
{
    uint8_t* buffer = grow(sizeof(n), sizeof(n));
    copyValueToBuffer(n, buffer);
}

void Encoder::encode(uint8_t n)
{
    uint8_t* buffer = grow(sizeof(n), sizeof(n));
    copyValueToBuffer(n, buffer);
}

void Encoder::encode(uint16_t n)
{
    uint8_t* buffer = grow(sizeof(n), sizeof(n));
    copyValueToBuffer(n, buffer);
}

void Encoder::encode(uint32_t n)
{
    uint8_t* buffer = grow(sizeof(n), sizeof(n));
    copyValueToBuffer(n, buffer);
}

void Encoder::encode(uint64_t n)
{
    uint8_t* buffer = grow(sizeof(n), sizeof(n));
    copyValueToBuffer(n, buffer);
}

void Encoder::encode(int16_t n)
{
    uint8_t* buffer = grow(sizeof(n), sizeof(n));
    copyValueToBuffer(n, buffer);
}

void Encoder::encode(int32_t n)
{
    uint8_t* buffer = grow(sizeof(n), sizeof(n));
    copyValueToBuffer(n, buffer);
}

void Encoder::encode(int64_t n)
{
    uint8_t* buffer = grow(sizeof(n), sizeof(n));
    copyValueToBuffer(n, buffer);
}

void Encoder::encode(float n)
{
    uint8_t* buffer = grow(sizeof(n), sizeof(n));
    copyValueToBuffer(n, buffer);
}

void Encoder::encode(double n)
{
    uint8_t* buffer = grow(sizeof(n), sizeof(n));
    copyValueToBuffer(n, buffer);
}

void Encoder::addAttachment(Attachment&& attachment)
{
    m_attachments.append(WTFMove(attachment));
}

Vector<Attachment> Encoder::releaseAttachments()
{
    return WTFMove(m_attachments);
}

} // namespace IPC