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// Copyright 2010 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/message_loop/message_pump.h"
#include "base/check.h"
#include "base/message_loop/io_watcher.h"
#include "base/message_loop/message_pump_default.h"
#include "base/message_loop/message_pump_for_io.h"
#include "base/message_loop/message_pump_for_ui.h"
#include "base/notreached.h"
#include "base/task/current_thread.h"
#include "base/task/task_features.h"
#include "base/threading/platform_thread.h"
#include "base/time/time.h"
#include "build/build_config.h"
#if BUILDFLAG(IS_APPLE)
#include "base/message_loop/message_pump_apple.h"
#endif
namespace base {
namespace {
constexpr uint64_t kAlignWakeUpsMask = 1;
constexpr uint64_t kLeewayOffset = 1;
constexpr uint64_t PackAlignWakeUpsAndLeeway(bool align_wake_ups,
TimeDelta leeway) {
return (static_cast<uint64_t>(leeway.InMilliseconds()) << kLeewayOffset) |
(align_wake_ups ? kAlignWakeUpsMask : 0);
}
// This stores the current state of |kAlignWakeUps| and leeway. The last bit
// represents if |kAlignWakeUps| is enabled, and the other bits represent the
// leeway value applied to delayed tasks in milliseconds. An atomic is used here
// because the value is queried from multiple threads.
std::atomic<uint64_t> g_align_wake_ups_and_leeway =
PackAlignWakeUpsAndLeeway(false, kDefaultLeeway);
MessagePump::MessagePumpFactory* message_pump_for_ui_factory_ = nullptr;
#if !BUILDFLAG(IS_NACL) && BUILDFLAG(IS_POSIX)
class MessagePumpForIOFdWatchImpl : public IOWatcher::FdWatch,
public MessagePumpForIO::FdWatcher {
public:
MessagePumpForIOFdWatchImpl(IOWatcher::FdWatcher* fd_watcher,
const Location& location)
: fd_watcher_(fd_watcher), controller_(location) {}
~MessagePumpForIOFdWatchImpl() override {
controller_.StopWatchingFileDescriptor();
}
MessagePumpForIO::FdWatchController& controller() { return controller_; }
private:
// MessagePumpForIO::FdWatcher:
void OnFileCanReadWithoutBlocking(int fd) override {
fd_watcher_->OnFdReadable(fd);
}
void OnFileCanWriteWithoutBlocking(int fd) override {
fd_watcher_->OnFdWritable(fd);
}
const raw_ptr<IOWatcher::FdWatcher> fd_watcher_;
MessagePumpForIO::FdWatchController controller_;
};
#endif
class IOWatcherForCurrentIOThread : public IOWatcher {
public:
IOWatcherForCurrentIOThread() : thread_(CurrentIOThread::Get()) {}
// IOWatcher:
#if !BUILDFLAG(IS_NACL)
#if BUILDFLAG(IS_WIN)
bool RegisterIOHandlerImpl(HANDLE file,
MessagePumpForIO::IOHandler* handler) override {
return thread_.RegisterIOHandler(file, handler);
}
bool RegisterJobObjectImpl(HANDLE job,
MessagePumpForIO::IOHandler* handler) override {
return thread_.RegisterJobObject(job, handler);
}
#elif BUILDFLAG(IS_POSIX)
std::unique_ptr<FdWatch> WatchFileDescriptorImpl(
int fd,
FdWatchDuration duration,
FdWatchMode mode,
FdWatcher& fd_watcher,
const Location& location) override {
MessagePumpForIO::Mode io_mode;
switch (mode) {
case FdWatchMode::kRead:
io_mode = MessagePumpForIO::WATCH_READ;
break;
case FdWatchMode::kWrite:
io_mode = MessagePumpForIO::WATCH_WRITE;
break;
case FdWatchMode::kReadWrite:
io_mode = MessagePumpForIO::WATCH_READ_WRITE;
break;
}
const bool is_persistent = duration == FdWatchDuration::kPersistent;
auto watch =
std::make_unique<MessagePumpForIOFdWatchImpl>(&fd_watcher, location);
if (!thread_.WatchFileDescriptor(fd, is_persistent, io_mode,
&watch->controller(), watch.get())) {
return nullptr;
}
return watch;
}
#endif
#if BUILDFLAG(IS_MAC) || \
(BUILDFLAG(IS_IOS) && !BUILDFLAG(CRONET_BUILD) && !BUILDFLAG(IS_IOS_TVOS))
bool WatchMachReceivePortImpl(
mach_port_t port,
MessagePumpForIO::MachPortWatchController* controller,
MessagePumpForIO::MachPortWatcher* delegate) override {
return thread_.WatchMachReceivePort(port, controller, delegate);
}
#elif BUILDFLAG(IS_FUCHSIA)
bool WatchZxHandleImpl(zx_handle_t handle,
bool persistent,
zx_signals_t signals,
MessagePumpForIO::ZxHandleWatchController* controller,
MessagePumpForIO::ZxHandleWatcher* delegate) override {
return thread_.WatchZxHandle(handle, persistent, signals, controller,
delegate);
}
#endif // BUILDFLAG(IS_FUCHSIA)
#endif // !BUILDFLAG(IS_NACL)
private:
CurrentIOThread thread_;
};
} // namespace
MessagePump::MessagePump() = default;
MessagePump::~MessagePump() = default;
bool MessagePump::HandleNestedNativeLoopWithApplicationTasks(
bool application_tasks_desired) {
return false;
}
// static
void MessagePump::OverrideMessagePumpForUIFactory(MessagePumpFactory* factory) {
DCHECK(!message_pump_for_ui_factory_);
message_pump_for_ui_factory_ = factory;
}
// static
bool MessagePump::IsMessagePumpForUIFactoryOveridden() {
return message_pump_for_ui_factory_ != nullptr;
}
// static
std::unique_ptr<MessagePump> MessagePump::Create(MessagePumpType type) {
switch (type) {
case MessagePumpType::UI:
if (message_pump_for_ui_factory_) {
return message_pump_for_ui_factory_();
}
#if BUILDFLAG(IS_APPLE)
return message_pump_apple::Create();
#elif BUILDFLAG(IS_NACL) || BUILDFLAG(IS_AIX)
// Currently NaCl and AIX don't have a UI MessagePump.
// TODO(abarth): Figure out if we need this.
NOTREACHED();
#elif BUILDFLAG(IS_ANDROID)
{
auto message_pump = std::make_unique<MessagePumpAndroid>();
message_pump->set_is_type_ui(true);
return message_pump;
}
#else
return std::make_unique<MessagePumpForUI>();
#endif
case MessagePumpType::IO:
return std::make_unique<MessagePumpForIO>();
#if BUILDFLAG(IS_ANDROID)
case MessagePumpType::JAVA:
return std::make_unique<MessagePumpAndroid>();
#endif
#if BUILDFLAG(IS_APPLE)
case MessagePumpType::NS_RUNLOOP:
return std::make_unique<MessagePumpNSRunLoop>();
#endif
case MessagePumpType::CUSTOM:
NOTREACHED();
case MessagePumpType::DEFAULT:
#if BUILDFLAG(IS_IOS)
// On iOS, a native runloop is always required to pump system work.
return std::make_unique<MessagePumpCFRunLoop>();
#else
return std::make_unique<MessagePumpDefault>();
#endif
}
}
// static
void MessagePump::InitializeFeatures() {
ResetAlignWakeUpsState();
#if BUILDFLAG(IS_WIN)
MessagePumpWin::InitializeFeatures();
#elif BUILDFLAG(IS_ANDROID)
MessagePumpAndroid::InitializeFeatures();
#endif
}
// static
void MessagePump::OverrideAlignWakeUpsState(bool enabled, TimeDelta leeway) {
g_align_wake_ups_and_leeway.store(PackAlignWakeUpsAndLeeway(enabled, leeway),
std::memory_order_relaxed);
}
// static
void MessagePump::ResetAlignWakeUpsState() {
OverrideAlignWakeUpsState(FeatureList::IsEnabled(kAlignWakeUps),
kTaskLeewayParam.Get());
}
// static
bool MessagePump::GetAlignWakeUpsEnabled() {
return g_align_wake_ups_and_leeway.load(std::memory_order_relaxed) &
kAlignWakeUpsMask;
}
// static
TimeDelta MessagePump::GetLeewayIgnoringThreadOverride() {
return Milliseconds(
g_align_wake_ups_and_leeway.load(std::memory_order_relaxed) >>
kLeewayOffset);
}
// static
TimeDelta MessagePump::GetLeewayForCurrentThread() {
// For some threads, there might be an override of the leeway, so check it
// first.
auto leeway_override = PlatformThread::GetThreadLeewayOverride();
if (leeway_override.has_value()) {
return leeway_override.value();
}
return GetLeewayIgnoringThreadOverride();
}
TimeTicks MessagePump::AdjustDelayedRunTime(TimeTicks earliest_time,
TimeTicks run_time,
TimeTicks latest_time) {
const TimeDelta leeway = GetLeewayForCurrentThread();
#if BUILDFLAG(IS_WIN)
// On Windows, we can rely on the low-res clock if we want the wakeup within
// kMinLowResolutionThresholdMs (16ms).
if (GetAlignWakeUpsEnabled() &&
leeway > Milliseconds(Time::kMinLowResolutionThresholdMs)) {
TimeTicks aligned_run_time =
earliest_time.SnappedToNextTick(TimeTicks(), leeway);
return std::min(aligned_run_time, latest_time);
}
// We need to return `earliest_time` to honor the above dependency on the
// low-res clock. Note: If this wakeup has a DelayPolicy::kPrecise, then
// `earliest_time == run_time` and we're thus fine returning `earliest_time`
// even though `run_time` is semantically what we want...
return earliest_time;
#else
if (GetAlignWakeUpsEnabled()) {
TimeTicks aligned_run_time =
earliest_time.SnappedToNextTick(TimeTicks(), leeway);
return std::min(aligned_run_time, latest_time);
}
return run_time;
#endif // BUILDFLAG(IS_WIN)
}
IOWatcher* MessagePump::GetIOWatcher() {
// By default only "IO thread" message pumps support async IO.
//
// TODO(crbug.com/379190028): This is done for convenience given the
// preexistence of CurrentIOThread, but we should eventually remove this in
// favor of each IO MessagePump implementation defining their own override.
if (!io_watcher_ && CurrentIOThread::IsSet()) {
io_watcher_ = std::make_unique<IOWatcherForCurrentIOThread>();
}
return io_watcher_.get();
}
} // namespace base
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