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clock.cpp
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// Copyright 2017 Open Source Robotics Foundation, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "rclcpp/clock.hpp"
#include <condition_variable>
#include <memory>
#include <thread>
#include "rclcpp/exceptions.hpp"
#include "rclcpp/utilities.hpp"
#include "rcpputils/scope_exit.hpp"
#include "rcutils/logging_macros.h"
namespace rclcpp
{
class Clock::Impl
{
public:
explicit Impl(rcl_clock_type_t clock_type)
: allocator_{rcl_get_default_allocator()}
{
rcl_ret_t ret = rcl_clock_init(clock_type, &rcl_clock_, &allocator_);
if (ret != RCL_RET_OK) {
exceptions::throw_from_rcl_error(ret, "failed to initialize rcl clock");
}
}
~Impl()
{
rcl_ret_t ret = rcl_clock_fini(&rcl_clock_);
if (ret != RCL_RET_OK) {
RCUTILS_LOG_ERROR("Failed to fini rcl clock.");
}
}
rcl_clock_t rcl_clock_;
rcl_allocator_t allocator_;
bool stop_sleeping_ = false;
bool shutdown_ = false;
std::condition_variable cv_;
std::mutex wait_mutex_;
std::mutex clock_mutex_;
};
JumpHandler::JumpHandler(
pre_callback_t pre_callback,
post_callback_t post_callback,
const rcl_jump_threshold_t & threshold)
: pre_callback(pre_callback),
post_callback(post_callback),
notice_threshold(threshold)
{}
Clock::Clock(rcl_clock_type_t clock_type)
: impl_(new Clock::Impl(clock_type)) {}
Clock::~Clock() {}
Time
Clock::now() const
{
Time now(0, 0, impl_->rcl_clock_.type);
auto ret = rcl_clock_get_now(&impl_->rcl_clock_, &now.rcl_time_.nanoseconds);
if (ret != RCL_RET_OK) {
exceptions::throw_from_rcl_error(ret, "could not get current time stamp");
}
return now;
}
void
Clock::cancel_sleep_or_wait()
{
{
std::unique_lock lock(impl_->wait_mutex_);
impl_->stop_sleeping_ = true;
}
impl_->cv_.notify_one();
}
bool
Clock::sleep_until(
Time until,
Context::SharedPtr context)
{
if (!context || !context->is_valid()) {
throw std::runtime_error("context cannot be slept with because it's invalid");
}
const auto this_clock_type = get_clock_type();
if (until.get_clock_type() != this_clock_type) {
throw std::runtime_error("until's clock type does not match this clock's type");
}
bool time_source_changed = false;
// Wake this thread if the context is shutdown
rclcpp::OnShutdownCallbackHandle shutdown_cb_handle = context->add_on_shutdown_callback(
[this]() {
{
std::unique_lock lock(impl_->wait_mutex_);
impl_->shutdown_ = true;
}
impl_->cv_.notify_one();
});
// No longer need the shutdown callback when this function exits
auto callback_remover = rcpputils::scope_exit(
[context, &shutdown_cb_handle]() {
context->remove_on_shutdown_callback(shutdown_cb_handle);
});
if (this_clock_type == RCL_STEADY_TIME) {
// Synchronize because RCL steady clock epoch might differ from chrono::steady_clock epoch
const Time rcl_entry = now();
const std::chrono::steady_clock::time_point chrono_entry = std::chrono::steady_clock::now();
const Duration delta_t = until - rcl_entry;
const std::chrono::steady_clock::time_point chrono_until =
chrono_entry + std::chrono::nanoseconds(delta_t.nanoseconds());
// loop over spurious wakeups but notice shutdown or stop of sleep
std::unique_lock lock(impl_->wait_mutex_);
while (now() < until && !impl_->stop_sleeping_ && !impl_->shutdown_ && context->is_valid()) {
impl_->cv_.wait_until(lock, chrono_until);
}
impl_->stop_sleeping_ = false;
} else if (this_clock_type == RCL_SYSTEM_TIME) {
auto system_time = std::chrono::system_clock::time_point(
// Cast because system clock resolution is too big for nanoseconds on some systems
std::chrono::duration_cast<std::chrono::system_clock::duration>(
std::chrono::nanoseconds(until.nanoseconds())));
// loop over spurious wakeups but notice shutdown or stop of sleep
std::unique_lock lock(impl_->wait_mutex_);
while (now() < until && !impl_->stop_sleeping_ && !impl_->shutdown_ && context->is_valid()) {
impl_->cv_.wait_until(lock, system_time);
}
impl_->stop_sleeping_ = false;
} else if (this_clock_type == RCL_ROS_TIME) {
// Install jump handler for any amount of time change, for two purposes:
// - if ROS time is active, check if time reached on each new clock sample
// - Trigger via on_clock_change to detect if time source changes, to invalidate sleep
rcl_jump_threshold_t threshold;
threshold.on_clock_change = true;
// 0 is disable, so -1 and 1 are smallest possible time changes
threshold.min_backward.nanoseconds = -1;
threshold.min_forward.nanoseconds = 1;
auto clock_handler = create_jump_callback(
nullptr,
[this, &time_source_changed](const rcl_time_jump_t & jump) {
if (jump.clock_change != RCL_ROS_TIME_NO_CHANGE) {
std::lock_guard<std::mutex> lk(impl_->wait_mutex_);
time_source_changed = true;
}
impl_->cv_.notify_one();
},
threshold);
if (!ros_time_is_active()) {
auto system_time = std::chrono::system_clock::time_point(
// Cast because system clock resolution is too big for nanoseconds on some systems
std::chrono::duration_cast<std::chrono::system_clock::duration>(
std::chrono::nanoseconds(until.nanoseconds())));
// loop over spurious wakeups but notice shutdown, stop of sleep or time source change
std::unique_lock lock(impl_->wait_mutex_);
while (now() < until && !impl_->stop_sleeping_ && !impl_->shutdown_ && context->is_valid() &&
!time_source_changed)
{
impl_->cv_.wait_until(lock, system_time);
}
impl_->stop_sleeping_ = false;
} else {
// RCL_ROS_TIME with ros_time_is_active.
// Just wait without "until" because installed
// jump callbacks wake the cv on every new sample.
std::unique_lock lock(impl_->wait_mutex_);
while (now() < until && !impl_->stop_sleeping_ && !impl_->shutdown_ && context->is_valid() &&
!time_source_changed)
{
impl_->cv_.wait(lock);
}
impl_->stop_sleeping_ = false;
}
}
if (!context->is_valid() || time_source_changed) {
return false;
}
return now() >= until;
}
bool
Clock::sleep_for(Duration rel_time, Context::SharedPtr context)
{
return sleep_until(now() + rel_time, context);
}
bool
Clock::started()
{
if (!rcl_clock_valid(get_clock_handle())) {
throw std::runtime_error("clock is not rcl_clock_valid");
}
return rcl_clock_time_started(get_clock_handle());
}
bool
Clock::wait_until_started(Context::SharedPtr context)
{
if (!context || !context->is_valid()) {
throw std::runtime_error("context cannot be slept with because it's invalid");
}
if (!rcl_clock_valid(get_clock_handle())) {
throw std::runtime_error("clock cannot be waited on as it is not rcl_clock_valid");
}
if (started()) {
return true;
} else {
// Wait until the first non-zero time
return sleep_until(rclcpp::Time(0, 1, get_clock_type()), context);
}
}
bool
Clock::wait_until_started(
const Duration & timeout,
Context::SharedPtr context,
const Duration & wait_tick_ns)
{
if (!context || !context->is_valid()) {
throw std::runtime_error("context cannot be slept with because it's invalid");
}
if (!rcl_clock_valid(get_clock_handle())) {
throw std::runtime_error("clock cannot be waited on as it is not rcl_clock_valid");
}
Clock timeout_clock = Clock(RCL_STEADY_TIME);
Time start = timeout_clock.now();
// Check if the clock has started every wait_tick_ns nanoseconds
// Context check checks for rclcpp::shutdown()
while (!started() && context->is_valid()) {
if (timeout < wait_tick_ns) {
timeout_clock.sleep_for(timeout);
} else {
Duration time_left = start + timeout - timeout_clock.now();
if (time_left > wait_tick_ns) {
timeout_clock.sleep_for(Duration(wait_tick_ns));
} else {
timeout_clock.sleep_for(time_left);
}
}
if (timeout_clock.now() - start > timeout) {
return started();
}
}
return started();
}
bool
Clock::ros_time_is_active()
{
if (!rcl_clock_valid(&impl_->rcl_clock_)) {
RCUTILS_LOG_ERROR("ROS time not valid!");
return false;
}
bool is_enabled = false;
auto ret = rcl_is_enabled_ros_time_override(&impl_->rcl_clock_, &is_enabled);
if (ret != RCL_RET_OK) {
exceptions::throw_from_rcl_error(
ret, "Failed to check ros_time_override_status");
}
return is_enabled;
}
rcl_clock_t *
Clock::get_clock_handle() noexcept
{
return &impl_->rcl_clock_;
}
rcl_clock_type_t
Clock::get_clock_type() const noexcept
{
return impl_->rcl_clock_.type;
}
std::mutex &
Clock::get_clock_mutex() noexcept
{
return impl_->clock_mutex_;
}
void
Clock::on_time_jump(
const rcl_time_jump_t * time_jump,
bool before_jump,
void * user_data)
{
const auto * handler = static_cast<JumpHandler *>(user_data);
if (nullptr == handler) {
return;
}
if (before_jump && handler->pre_callback) {
handler->pre_callback();
} else if (!before_jump && handler->post_callback) {
handler->post_callback(*time_jump);
}
}
JumpHandler::SharedPtr
Clock::create_jump_callback(
JumpHandler::pre_callback_t pre_callback,
JumpHandler::post_callback_t post_callback,
const rcl_jump_threshold_t & threshold)
{
// Allocate a new jump handler
JumpHandler::UniquePtr handler(new JumpHandler(pre_callback, post_callback, threshold));
if (nullptr == handler) {
throw std::bad_alloc{};
}
{
std::lock_guard<std::mutex> clock_guard(impl_->clock_mutex_);
// Try to add the jump callback to the clock
rcl_ret_t ret = rcl_clock_add_jump_callback(
&impl_->rcl_clock_, threshold, Clock::on_time_jump,
handler.get());
if (RCL_RET_OK != ret) {
exceptions::throw_from_rcl_error(ret, "Failed to add time jump callback");
}
}
std::weak_ptr<Clock::Impl> weak_impl = impl_;
// *INDENT-OFF*
// create shared_ptr that removes the callback automatically when all copies are destructed
return JumpHandler::SharedPtr(handler.release(), [weak_impl](JumpHandler * handler) noexcept {
auto shared_impl = weak_impl.lock();
if (shared_impl) {
std::lock_guard<std::mutex> clock_guard(shared_impl->clock_mutex_);
rcl_ret_t ret = rcl_clock_remove_jump_callback(&shared_impl->rcl_clock_,
Clock::on_time_jump, handler);
if (RCL_RET_OK != ret) {
RCUTILS_LOG_ERROR("Failed to remove time jump callback");
}
}
delete handler;
});
// *INDENT-ON*
}
} // namespace rclcpp