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-rw-r--r--src/common/polyfill_thread.h83
1 files changed, 46 insertions, 37 deletions
diff --git a/src/common/polyfill_thread.h b/src/common/polyfill_thread.h
index b2c929d2f..b4c94a5fc 100644
--- a/src/common/polyfill_thread.h
+++ b/src/common/polyfill_thread.h
@@ -41,17 +41,18 @@ bool StoppableTimedWait(std::stop_token token, const std::chrono::duration<Rep,
#include <chrono>
#include <condition_variable>
#include <functional>
-#include <list>
+#include <map>
#include <memory>
#include <mutex>
#include <optional>
#include <thread>
#include <type_traits>
+#include <utility>
namespace std {
namespace polyfill {
-using stop_state_callbacks = list<function<void()>>;
+using stop_state_callback = size_t;
class stop_state {
public:
@@ -59,61 +60,69 @@ public:
~stop_state() = default;
bool request_stop() {
- stop_state_callbacks callbacks;
+ unique_lock lk{m_lock};
- {
- scoped_lock lk{m_lock};
+ if (m_stop_requested) {
+ // Already set, nothing to do.
+ return false;
+ }
- if (m_stop_requested.load()) {
- // Already set, nothing to do
- return false;
- }
+ // Mark stop requested.
+ m_stop_requested = true;
- // Set as requested
- m_stop_requested = true;
+ while (!m_callbacks.empty()) {
+ // Get an iterator to the first element.
+ const auto it = m_callbacks.begin();
- // Copy callback list
- callbacks = m_callbacks;
- }
+ // Move the callback function out of the map.
+ function<void()> f;
+ swap(it->second, f);
+
+ // Erase the now-empty map element.
+ m_callbacks.erase(it);
- for (auto callback : callbacks) {
- callback();
+ // Run the callback.
+ if (f) {
+ f();
+ }
}
return true;
}
bool stop_requested() const {
- return m_stop_requested.load();
+ unique_lock lk{m_lock};
+ return m_stop_requested;
}
- stop_state_callbacks::const_iterator insert_callback(function<void()> f) {
- stop_state_callbacks::const_iterator ret{};
- bool should_run{};
-
- {
- scoped_lock lk{m_lock};
- should_run = m_stop_requested.load();
- m_callbacks.push_front(f);
- ret = m_callbacks.begin();
- }
+ stop_state_callback insert_callback(function<void()> f) {
+ unique_lock lk{m_lock};
- if (should_run) {
- f();
+ if (m_stop_requested) {
+ // Stop already requested. Don't insert anything,
+ // just run the callback synchronously.
+ if (f) {
+ f();
+ }
+ return 0;
}
+ // Insert the callback.
+ stop_state_callback ret = ++m_next_callback;
+ m_callbacks.emplace(ret, move(f));
return ret;
}
- void remove_callback(stop_state_callbacks::const_iterator it) {
- scoped_lock lk{m_lock};
- m_callbacks.erase(it);
+ void remove_callback(stop_state_callback cb) {
+ unique_lock lk{m_lock};
+ m_callbacks.erase(cb);
}
private:
- mutex m_lock;
- atomic<bool> m_stop_requested;
- stop_state_callbacks m_callbacks;
+ mutable recursive_mutex m_lock;
+ map<stop_state_callback, function<void()>> m_callbacks;
+ stop_state_callback m_next_callback{0};
+ bool m_stop_requested{false};
};
} // namespace polyfill
@@ -223,7 +232,7 @@ public:
}
~stop_callback() {
if (m_stop_state && m_callback) {
- m_stop_state->remove_callback(*m_callback);
+ m_stop_state->remove_callback(m_callback);
}
}
@@ -234,7 +243,7 @@ public:
private:
shared_ptr<polyfill::stop_state> m_stop_state;
- optional<polyfill::stop_state_callbacks::const_iterator> m_callback;
+ polyfill::stop_state_callback m_callback;
};
template <typename Callback>