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// Copyright 2013 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 "mojo/common/message_pump_mojo.h"
#include <algorithm>
#include <vector>
#include "base/logging.h"
#include "base/time/time.h"
#include "mojo/common/message_pump_mojo_handler.h"
#include "mojo/common/time_helper.h"
namespace mojo {
namespace common {
// State needed for one iteration of WaitMany. The first handle and flags
// corresponds to that of the control pipe.
struct MessagePumpMojo::WaitState {
std::vector<Handle> handles;
std::vector<MojoWaitFlags> wait_flags;
};
struct MessagePumpMojo::RunState {
RunState() : should_quit(false) {
CreateMessagePipe(&read_handle, &write_handle);
}
base::TimeTicks delayed_work_time;
// Used to wake up WaitForWork().
ScopedMessagePipeHandle read_handle;
ScopedMessagePipeHandle write_handle;
bool should_quit;
};
MessagePumpMojo::MessagePumpMojo() : run_state_(NULL), next_handler_id_(0) {
}
MessagePumpMojo::~MessagePumpMojo() {
}
// static
scoped_ptr<base::MessagePump> MessagePumpMojo::Create() {
return scoped_ptr<MessagePump>(new MessagePumpMojo());
}
void MessagePumpMojo::AddHandler(MessagePumpMojoHandler* handler,
const Handle& handle,
MojoWaitFlags wait_flags,
base::TimeTicks deadline) {
DCHECK(handler);
DCHECK(handle.is_valid());
// Assume it's an error if someone tries to reregister an existing handle.
DCHECK_EQ(0u, handlers_.count(handle));
Handler handler_data;
handler_data.handler = handler;
handler_data.wait_flags = wait_flags;
handler_data.deadline = deadline;
handler_data.id = next_handler_id_++;
handlers_[handle] = handler_data;
}
void MessagePumpMojo::RemoveHandler(const Handle& handle) {
handlers_.erase(handle);
}
void MessagePumpMojo::Run(Delegate* delegate) {
RunState run_state;
// TODO: better deal with error handling.
CHECK(run_state.read_handle.is_valid());
CHECK(run_state.write_handle.is_valid());
RunState* old_state = NULL;
{
base::AutoLock auto_lock(run_state_lock_);
old_state = run_state_;
run_state_ = &run_state;
}
DoRunLoop(&run_state, delegate);
{
base::AutoLock auto_lock(run_state_lock_);
run_state_ = old_state;
}
}
void MessagePumpMojo::Quit() {
base::AutoLock auto_lock(run_state_lock_);
if (run_state_)
run_state_->should_quit = true;
}
void MessagePumpMojo::ScheduleWork() {
base::AutoLock auto_lock(run_state_lock_);
if (run_state_)
SignalControlPipe(*run_state_);
}
void MessagePumpMojo::ScheduleDelayedWork(
const base::TimeTicks& delayed_work_time) {
base::AutoLock auto_lock(run_state_lock_);
if (!run_state_)
return;
run_state_->delayed_work_time = delayed_work_time;
SignalControlPipe(*run_state_);
}
void MessagePumpMojo::DoRunLoop(RunState* run_state, Delegate* delegate) {
bool more_work_is_plausible = true;
for (;;) {
const bool block = !more_work_is_plausible;
DoInternalWork(*run_state, block);
// There isn't a good way to know if there are more handles ready, we assume
// not.
more_work_is_plausible = false;
if (run_state->should_quit)
break;
more_work_is_plausible |= delegate->DoWork();
if (run_state->should_quit)
break;
more_work_is_plausible |= delegate->DoDelayedWork(
&run_state->delayed_work_time);
if (run_state->should_quit)
break;
if (more_work_is_plausible)
continue;
more_work_is_plausible = delegate->DoIdleWork();
if (run_state->should_quit)
break;
}
}
void MessagePumpMojo::DoInternalWork(const RunState& run_state, bool block) {
const MojoDeadline deadline = block ? GetDeadlineForWait(run_state) : 0;
const WaitState wait_state = GetWaitState(run_state);
const MojoResult result =
WaitMany(wait_state.handles, wait_state.wait_flags, deadline);
if (result == 0) {
// Control pipe was written to.
uint32_t num_bytes = 0;
ReadMessageRaw(run_state.read_handle.get(), NULL, &num_bytes, NULL, NULL,
MOJO_READ_MESSAGE_FLAG_MAY_DISCARD);
} else if (result > 0) {
const size_t index = static_cast<size_t>(result);
DCHECK(handlers_.find(wait_state.handles[index]) != handlers_.end());
handlers_[wait_state.handles[index]].handler->OnHandleReady(
wait_state.handles[index]);
} else {
switch (result) {
case MOJO_RESULT_INVALID_ARGUMENT:
case MOJO_RESULT_FAILED_PRECONDITION:
RemoveFirstInvalidHandle(wait_state);
break;
case MOJO_RESULT_DEADLINE_EXCEEDED:
break;
default:
NOTREACHED();
}
}
// Notify and remove any handlers whose time has expired. Make a copy in case
// someone tries to add/remove new handlers from notification.
const HandleToHandler cloned_handlers(handlers_);
const base::TimeTicks now(internal::NowTicks());
for (HandleToHandler::const_iterator i = cloned_handlers.begin();
i != cloned_handlers.end(); ++i) {
// Since we're iterating over a clone of the handlers, verify the handler is
// still valid before notifying.
if (!i->second.deadline.is_null() && i->second.deadline < now &&
handlers_.find(i->first) != handlers_.end() &&
handlers_[i->first].id == i->second.id) {
i->second.handler->OnHandleError(i->first, MOJO_RESULT_DEADLINE_EXCEEDED);
}
}
}
void MessagePumpMojo::RemoveFirstInvalidHandle(const WaitState& wait_state) {
// TODO(sky): deal with control pipe going bad.
for (size_t i = 1; i < wait_state.handles.size(); ++i) {
const MojoResult result =
Wait(wait_state.handles[i], wait_state.wait_flags[i], 0);
if (result == MOJO_RESULT_INVALID_ARGUMENT ||
result == MOJO_RESULT_FAILED_PRECONDITION) {
// Remove the handle first, this way if OnHandleError() tries to remove
// the handle our iterator isn't invalidated.
DCHECK(handlers_.find(wait_state.handles[i]) != handlers_.end());
MessagePumpMojoHandler* handler =
handlers_[wait_state.handles[i]].handler;
handlers_.erase(wait_state.handles[i]);
handler->OnHandleError(wait_state.handles[i], result);
return;
}
}
}
void MessagePumpMojo::SignalControlPipe(const RunState& run_state) {
// TODO(sky): deal with error?
WriteMessageRaw(run_state.write_handle.get(), NULL, 0, NULL, 0,
MOJO_WRITE_MESSAGE_FLAG_NONE);
}
MessagePumpMojo::WaitState MessagePumpMojo::GetWaitState(
const RunState& run_state) const {
WaitState wait_state;
wait_state.handles.push_back(run_state.read_handle.get());
wait_state.wait_flags.push_back(MOJO_WAIT_FLAG_READABLE);
for (HandleToHandler::const_iterator i = handlers_.begin();
i != handlers_.end(); ++i) {
wait_state.handles.push_back(i->first);
wait_state.wait_flags.push_back(i->second.wait_flags);
}
return wait_state;
}
MojoDeadline MessagePumpMojo::GetDeadlineForWait(
const RunState& run_state) const {
base::TimeTicks min_time = run_state.delayed_work_time;
for (HandleToHandler::const_iterator i = handlers_.begin();
i != handlers_.end(); ++i) {
if (min_time.is_null() && i->second.deadline < min_time)
min_time = i->second.deadline;
}
return min_time.is_null() ? MOJO_DEADLINE_INDEFINITE :
std::max(static_cast<MojoDeadline>(0),
static_cast<MojoDeadline>(
(min_time - internal::NowTicks()).InMicroseconds()));
}
} // namespace common
} // namespace mojo
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