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// Copyright 2017 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/common/message_port.h"
#include "base/logging.h"
namespace content {
MessagePort::~MessagePort() {
}
MessagePort::MessagePort() : state_(new State()) {
}
MessagePort::MessagePort(const MessagePort& other) : state_(other.state_) {
}
MessagePort& MessagePort::operator=(const MessagePort& other) {
state_ = other.state_;
return *this;
}
MessagePort::MessagePort(mojo::ScopedMessagePipeHandle handle)
: state_(new State(std::move(handle))) {
}
const mojo::ScopedMessagePipeHandle& MessagePort::GetHandle() const {
return state_->handle_;
}
mojo::ScopedMessagePipeHandle MessagePort::ReleaseHandle() const {
state_->CancelWatch();
return std::move(state_->handle_);
}
// static
std::vector<mojo::ScopedMessagePipeHandle> MessagePort::ReleaseHandles(
const std::vector<MessagePort>& ports) {
std::vector<mojo::ScopedMessagePipeHandle> handles(ports.size());
for (size_t i = 0; i < ports.size(); ++i)
handles[i] = ports[i].ReleaseHandle();
return handles;
}
void MessagePort::PostMessage(const base::string16& encoded_message,
std::vector<MessagePort> ports) {
DCHECK(state_->handle_.is_valid());
uint32_t num_bytes = encoded_message.size() * sizeof(base::char16);
// NOTE: It is OK to ignore the return value of MojoWriteMessage here. HTML
// MessagePorts have no way of reporting when the peer is gone.
if (ports.empty()) {
MojoWriteMessage(state_->handle_.get().value(),
encoded_message.data(),
num_bytes,
nullptr,
0,
MOJO_WRITE_MESSAGE_FLAG_NONE);
} else {
uint32_t num_handles = static_cast<uint32_t>(ports.size());
std::unique_ptr<MojoHandle[]> handles(new MojoHandle[num_handles]);
for (uint32_t i = 0; i < num_handles; ++i)
handles[i] = ports[i].ReleaseHandle().release().value();
MojoWriteMessage(state_->handle_.get().value(),
encoded_message.data(),
num_bytes,
handles.get(),
num_handles,
MOJO_WRITE_MESSAGE_FLAG_NONE);
}
}
bool MessagePort::GetMessage(base::string16* encoded_message,
std::vector<MessagePort>* ports) {
DCHECK(state_->handle_.is_valid());
uint32_t num_bytes = 0;
uint32_t num_handles = 0;
MojoResult rv = MojoReadMessage(state_->handle_.get().value(),
nullptr,
&num_bytes,
nullptr,
&num_handles,
MOJO_READ_MESSAGE_FLAG_NONE);
if (rv == MOJO_RESULT_OK) {
encoded_message->clear();
ports->clear();
return true;
}
if (rv != MOJO_RESULT_RESOURCE_EXHAUSTED)
return false;
CHECK(num_bytes % 2 == 0);
base::string16 buffer;
buffer.resize(num_bytes / sizeof(base::char16));
std::unique_ptr<MojoHandle[]> handles;
if (num_handles)
handles.reset(new MojoHandle[num_handles]);
rv = MojoReadMessage(state_->handle_.get().value(),
num_bytes ? &buffer[0] : nullptr,
&num_bytes,
handles.get(),
&num_handles,
MOJO_READ_MESSAGE_FLAG_NONE);
if (rv != MOJO_RESULT_OK)
return false;
buffer.swap(*encoded_message);
if (num_handles) {
ports->resize(static_cast<size_t>(num_handles));
for (uint32_t i = 0; i < num_handles; ++i) {
ports->at(i) = MessagePort(
mojo::ScopedMessagePipeHandle(mojo::MessagePipeHandle(handles[i])));
}
}
return true;
}
void MessagePort::SetCallback(const base::Closure& callback) {
state_->CancelWatch();
state_->callback_ = callback;
state_->AddWatch();
}
void MessagePort::ClearCallback() {
state_->CancelWatch();
state_->callback_.Reset();
}
MessagePort::State::State() {
}
MessagePort::State::State(mojo::ScopedMessagePipeHandle handle)
: handle_(std::move(handle)) {
}
void MessagePort::State::AddWatch() {
if (!callback_)
return;
// NOTE: An HTML MessagePort does not receive an event to tell it when the
// peer has gone away, so we only watch for readability here.
MojoResult rv = MojoWatch(handle_.get().value(),
MOJO_HANDLE_SIGNAL_READABLE,
&MessagePort::State::OnHandleReady,
reinterpret_cast<uintptr_t>(this));
if (rv != MOJO_RESULT_OK)
DVLOG(1) << this << " MojoWatch failed: " << rv;
}
void MessagePort::State::CancelWatch() {
if (!callback_)
return;
// NOTE: This synchronizes with the thread where OnHandleReady runs so we are
// sure to not be racing with it.
MojoCancelWatch(handle_.get().value(), reinterpret_cast<uintptr_t>(this));
}
// static
void MessagePort::State::OnHandleReady(
uintptr_t context,
MojoResult result,
MojoHandleSignalsState signals_state,
MojoWatchNotificationFlags flags) {
if (result == MOJO_RESULT_OK) {
reinterpret_cast<MessagePort::State*>(context)->callback_.Run();
} else {
// And now his watch is ended.
}
}
MessagePort::State::~State() {
CancelWatch();
}
} // namespace content
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