mirror of
https://github.com/geode-sdk/geode.git
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1051 lines
48 KiB
C++
1051 lines
48 KiB
C++
#pragma once
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#include "general.hpp"
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#include "../loader/Event.hpp"
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#include "../loader/Loader.hpp"
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#include <mutex>
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#include <string_view>
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#include <coroutine>
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namespace geode {
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namespace geode_internal {
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template <class T, class P>
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struct TaskPromise;
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template <class T, class P>
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struct TaskAwaiter;
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}
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/**
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* Tasks represent an asynchronous operation that will be finished at some
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* unknown point in the future. Tasks can report their progress, and will
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* end either through finishing into a value, or due to being cancelled.
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* Tasks are designed to provide a thread-safe general purpose abstraction
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* for dealing with any asynchronous operations.
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* The `Task` class satisfies `EventFilter` and as such is listened
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* to using the Geode events system; tasks may have multiple listeners, and
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* even if a listener is attached after the Task has finished it will
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* receive the finished value.
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* Tasks are a very cheap and tiny struct that just have a reference to
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* a task Handle; as such, Tasks may (and should) be copied around without
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* worry. It should be noted that a Task never owns itself - the listener(s)
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* of a Task are expected to hold an instance of the Task for as long as
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* they intend to listen to it. Usually this is done via just setting
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* the Task as the filter to an `EventListener`, as the `EventListener`
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* manages the lifetime of its filter
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* Task itself does not carry a notion of fallibility aside from
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* cancellation; it is customary to use the `Result` type in Tasks that
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* might finish to a failure value.
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* Once a Task has finished or has been cancelled, it can no longer be
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* revived
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* @tparam T The type the Task will eventually finish to. This type must be
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* move-constructible; though as there is no way to move the value out
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* of the Task (because of potentially multiple listeners), one
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* should ensure they can reasonably copy the value out in some form if they
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* wish to gain ownership of it after the Task is finished
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* @tparam P The type of the progress values the Task (may) post
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*/
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template <std::move_constructible T, std::move_constructible P = std::monostate>
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class [[nodiscard]] Task final {
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public:
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/**
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* A struct used for cancelling Tasks; Tasks may return an instance of
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* this struct to cancel themselves, or to mark they have handled
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* outside cancellation
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*/
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struct [[nodiscard]] Cancel final {};
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/**
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* A simple holder for the result of this task; holds either the finished
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* value or a mark that the Task was cancelled. The Task body must return
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* this type (though it is implicitly convertible from T and Cancel
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* so the programmer rarely needs to explicitly name it)
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*/
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class Result final {
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private:
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std::variant<T, Cancel> m_value;
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std::optional<T> getValue() && {
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if (m_value.index() == 0) {
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return std::optional(std::move(std::get<0>(std::move(m_value))));
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}
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return std::nullopt;
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}
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bool isCancelled() const {
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return m_value.index() == 1;
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}
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template <std::move_constructible T2, std::move_constructible P2>
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friend class Task;
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public:
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Result(Result&&) = default;
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Result(Result const&) = delete;
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Result(T&& value) : m_value(std::in_place_index<0>, std::forward<T>(value)) {}
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Result(Cancel const&) : m_value(std::in_place_index<1>, Cancel()) {}
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// Allow constructing Results using anything that can be used to construct T
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template <class V>
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Result(V&& value) requires std::is_constructible_v<T, V&&>
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: m_value(std::in_place_index<0>, std::forward<V>(value))
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{}
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};
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/// The current status of a Task
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enum class Status {
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/// The task is still running or waiting to start
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Pending,
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/// The task has successfully finished
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Finished,
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/// The task has been cancelled
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Cancelled,
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};
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/**
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* A handle to a running Task. This is what actually keeps track of
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* the state of the current task; the `Task` class is simply an owning
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* reference & interface to one of these
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*/
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class Handle final {
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private:
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// Handles may contain extra data, for example for holding ownership
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// of other Tasks for `Task::map` and `Task::all`. This struct
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// provides type erasure for that extra data
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struct ExtraData final {
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// Pointer to the owned extra data
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void* ptr;
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// Pointer to a function that deletes that extra data
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// The function MUST have a static lifetime
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void(*onDestroy)(void*);
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// Pointer to a function that handles cancelling any tasks within
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// that extra data when this task is cancelled. Note that the
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// task may not free up the memory associated with itself here
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// and this function may not be called if the user uses
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// `Task::shallowCancel`. However, this pointer *must* always be
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// valid
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// The function MUST have a static lifetime
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void(*onCancelled)(void*);
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ExtraData(void* ptr, void(*onDestroy)(void*), void(*onCancelled)(void*))
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: ptr(ptr), onDestroy(onDestroy), onCancelled(onCancelled)
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{}
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ExtraData(ExtraData const&) = delete;
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ExtraData(ExtraData&&) = delete;
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~ExtraData() {
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onDestroy(ptr);
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}
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void cancel() {
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onCancelled(ptr);
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}
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};
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std::recursive_mutex m_mutex;
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Status m_status = Status::Pending;
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std::optional<T> m_resultValue;
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bool m_finalEventPosted = false;
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std::string m_name;
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std::unique_ptr<ExtraData> m_extraData = nullptr;
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class PrivateMarker final {};
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static std::shared_ptr<Handle> create(std::string_view name) {
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return std::make_shared<Handle>(PrivateMarker(), name);
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}
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bool is(Status status) {
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std::unique_lock<std::recursive_mutex> lock(m_mutex);
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return m_status == status;
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}
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template <std::move_constructible T2, std::move_constructible P2>
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friend class Task;
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template <class, class>
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friend struct geode_internal::TaskPromise;
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template <class, class>
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friend struct geode_internal::TaskAwaiter;
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public:
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Handle(PrivateMarker, std::string_view name) : m_name(name) {}
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~Handle() {
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// If this Task was still pending when the Handle was destroyed,
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// it can no longer be listened to so just cancel and cleanup
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std::unique_lock<std::recursive_mutex> lock(m_mutex);
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if (m_status == Status::Pending) {
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m_status = Status::Cancelled;
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// If this task carries extra data, call the extra data's
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// handling method
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// Actually: don't do this! This will cancel tasks even if
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// they have other listeners! The extra data's destructor
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// will handle cancellation if it has no other listeners!
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// if (m_extraData) {
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// m_extraData->cancel();
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// }
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// No need to actually post an event because this Task is
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// unlisteanable
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m_finalEventPosted = true;
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}
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}
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};
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/**
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* When the Task progresses, finishes, or is cancelled, one of these
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* is posted; the `Task` class itself is used as an event filter to
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* catch the task events for that specific task
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*/
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class Event final : public geode::Event {
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private:
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std::shared_ptr<Handle> m_handle;
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std::variant<T*, P*, Cancel> m_value;
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EventListenerProtocol* m_for = nullptr;
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Event(std::shared_ptr<Handle> handle, std::variant<T*, P*, Cancel>&& value)
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: m_handle(handle), m_value(std::move(value)) {}
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static Event createFinished(std::shared_ptr<Handle> handle, T* value) {
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return Event(handle, std::variant<T*, P*, Cancel>(std::in_place_index<0>, value));
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}
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static Event createProgressed(std::shared_ptr<Handle> handle, P* value) {
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return Event(handle, std::variant<T*, P*, Cancel>(std::in_place_index<1>, value));
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}
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static Event createCancelled(std::shared_ptr<Handle> handle) {
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return Event(handle, std::variant<T*, P*, Cancel>(std::in_place_index<2>, Cancel()));
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}
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template <std::move_constructible T2, std::move_constructible P2>
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friend class Task;
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public:
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/**
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* Get a reference to the contained finish value, or null if this
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* event holds a progress value or represents cancellation instead
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*/
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T* getValue() {
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return m_value.index() == 0 ? std::get<0>(m_value) : nullptr;
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}
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/**
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* Get a reference to the contained finish value, or null if this
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* event holds a progress value or represents cancellation instead
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*/
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T const* getValue() const {
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return m_value.index() == 0 ? std::get<0>(m_value) : nullptr;
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}
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/**
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* Get a reference to the contained progress value, or null if
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* this event holds a finish value or represents cancellation instead
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*/
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P* getProgress() {
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return m_value.index() == 1 ? std::get<1>(m_value) : nullptr;
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}
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/**
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* Get a reference to the contained progress value, or null if
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* this event holds a finish value or represents cancellation instead
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*/
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P const* getProgress() const {
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return m_value.index() == 1 ? std::get<1>(m_value) : nullptr;
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}
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/**
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* Check if the Task was cancelled
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*/
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bool isCancelled() const {
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return m_value.index() == 2;
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}
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/**
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* Cancel the Task that posted this event. If the task has
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* already finished or been cancelled, nothing happens
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*/
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void cancel() {
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Task::cancel(m_handle);
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}
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};
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using Value = T;
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using Progress = P;
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using PostResult = std::function<void(Result&&)>;
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using PostProgress = std::function<void(P)>;
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using HasBeenCancelled = std::function<bool()>;
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using Run = std::function<Result(PostProgress, HasBeenCancelled)>;
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using RunWithCallback = std::function<void(PostResult, PostProgress, HasBeenCancelled)>;
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using Callback = void(Event*);
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private:
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EventListenerProtocol* m_listener = nullptr;
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std::shared_ptr<Handle> m_handle;
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Task(std::shared_ptr<Handle> handle) : m_handle(handle) {}
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static void finish(std::shared_ptr<Handle> handle, T&& value) {
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if (!handle) return;
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std::unique_lock<std::recursive_mutex> lock(handle->m_mutex);
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if (handle->m_status == Status::Pending) {
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handle->m_status = Status::Finished;
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handle->m_resultValue.emplace(std::move(value));
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queueInMainThread([handle, value = &*handle->m_resultValue]() mutable {
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// SAFETY: Task::all() depends on the lifetime of the value pointer
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// being as long as the lifetime of the task itself
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Event::createFinished(handle, value).post();
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std::unique_lock<std::recursive_mutex> lock(handle->m_mutex);
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handle->m_finalEventPosted = true;
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});
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}
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}
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static void progress(std::shared_ptr<Handle> handle, P&& value) {
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if (!handle) return;
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std::unique_lock<std::recursive_mutex> lock(handle->m_mutex);
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if (handle->m_status == Status::Pending) {
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queueInMainThread([handle, value = std::move(value)]() mutable {
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Event::createProgressed(handle, &value).post();
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});
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}
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}
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static void cancel(std::shared_ptr<Handle> handle, bool shallow = false) {
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if (!handle) return;
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std::unique_lock<std::recursive_mutex> lock(handle->m_mutex);
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if (handle->m_status == Status::Pending) {
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handle->m_status = Status::Cancelled;
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// If this task carries extra data, call the extra data's handling method
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// (unless shallow cancelling was specifically requested)
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if (!shallow && handle->m_extraData) {
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handle->m_extraData->cancel();
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}
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queueInMainThread([handle]() mutable {
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Event::createCancelled(handle).post();
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std::unique_lock<std::recursive_mutex> lock(handle->m_mutex);
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handle->m_finalEventPosted = true;
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});
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}
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}
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template <std::move_constructible T2, std::move_constructible P2>
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friend class Task;
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template <class, class>
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friend struct geode_internal::TaskPromise;
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template <class, class>
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friend struct geode_internal::TaskAwaiter;
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public:
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// Allow default-construction
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Task() : m_handle(nullptr) {}
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Task(Task const& other) : m_handle(other.m_handle) {}
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Task(Task&& other) : m_handle(std::move(other.m_handle)) {}
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Task& operator=(Task const& other) {
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m_handle = other.m_handle;
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return *this;
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}
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Task& operator=(Task&& other) {
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m_handle = std::move(other.m_handle);
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return *this;
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}
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bool operator==(Task const& other) const {
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return m_handle == other.m_handle;
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}
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bool operator!=(Task const& other) const {
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return m_handle != other.m_handle;
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}
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bool operator<(Task const& other) const {
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return m_handle < other.m_handle;
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}
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bool operator<=(Task const& other) const {
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return m_handle <= other.m_handle;
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}
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bool operator>(Task const& other) const {
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return m_handle > other.m_handle;
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}
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bool operator>=(Task const& other) const {
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return m_handle >= other.m_handle;
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}
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/**
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* Get the value this Task finished to, if the Task had finished,
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* or null otherwise. Note that this is simply a mutable reference to
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* the value - *you may not move out of it!*
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*/
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T* getFinishedValue() {
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if (m_handle && m_handle->m_resultValue) {
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return &*m_handle->m_resultValue;
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}
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return nullptr;
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}
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/**
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* Cancel this Task. If this is a Task that owns other Task(s) (for example
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* one created through `Task::map`) then that Task is cancelled
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* as well. If this is undesirable, use `shallowCancel()`
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* instead
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*/
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void cancel() {
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Task::cancel(m_handle);
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}
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/**
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* If this is a Task that owns other Task(s) (for example created
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* through `Task::map` or `Task::all`), then this method cancels *only*
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* this Task and *not* any of the Task(s) it is built on top of.
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* Ownership of the other Task(s) will be released, so if this is the
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* only Task listening to them, they will still be destroyed due to a
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* lack of listeners
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*/
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void shallowCancel() {
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Task::cancel(m_handle, true);
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}
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bool isPending() const {
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return m_handle && m_handle->is(Status::Pending);
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}
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bool isFinished() const {
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return m_handle && m_handle->is(Status::Finished);
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}
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bool isCancelled() const {
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return m_handle && m_handle->is(Status::Cancelled);
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}
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/**
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* Check if this Task doesn't actually do anything (for instance it
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* was default-constructed)
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*/
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bool isNull() const {
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return m_handle == nullptr;
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}
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/**
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* Create a new Task that is immediately cancelled
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* @param name The name of the Task; used for debugging
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*/
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static Task cancelled(std::string_view name = "<Cancelled Task>") {
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auto task = Task(Handle::create(name));
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Task::cancel(task.m_handle);
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return task;
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}
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/**
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* Create a new Task that immediately finishes with the given
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* value
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* @param value The value the Task shall be finished with
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* @param name The name of the Task; used for debugging
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*/
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static Task immediate(T value, std::string_view name = "<Immediate Task>") {
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auto task = Task(Handle::create(name));
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Task::finish(task.m_handle, std::move(value));
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return task;
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}
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/**
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* Create a new Task with a function that returns the finished value.
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* See the class description for details about Tasks
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* @param body The body aka actual code of the Task. Note that this
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* function MUST be synchronous - Task creates the thread for you!
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* @param name The name of the Task; used for debugging
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*/
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static Task run(Run&& body, std::string_view name = "<Task>") {
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auto task = Task(Handle::create(name));
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std::thread([handle = std::weak_ptr(task.m_handle), name = std::string(name), body = std::move(body)] {
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utils::thread::setName(fmt::format("Task '{}'", name));
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auto result = body(
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[handle](P progress) {
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Task::progress(handle.lock(), std::move(progress));
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},
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[handle]() -> bool {
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// The task has been cancelled if the user has explicitly cancelled it,
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// or if there is no one listening anymore
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auto lock = handle.lock();
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return !(lock && lock->is(Status::Pending));
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}
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);
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if (result.isCancelled()) {
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Task::cancel(handle.lock());
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}
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else {
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Task::finish(handle.lock(), std::move(*std::move(result).getValue()));
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}
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}).detach();
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return task;
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}
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/**
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* Create a Task using a body that may need to create additional
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* threads within itself; for example due to using an external
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* library that creates its own thread
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* @param body The body aka actual code of the Task. The body may
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* call its provided finish callback *exactly once* - subsequent
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* calls will always be ignored
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* @param name The name of the Task; used for debugging
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*/
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static Task runWithCallback(RunWithCallback&& body, std::string_view name = "<Callback Task>") {
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auto task = Task(Handle::create(name));
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std::thread([handle = std::weak_ptr(task.m_handle), name = std::string(name), body = std::move(body)] {
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utils::thread::setName(fmt::format("Task '{}'", name));
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body(
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[handle](Result result) {
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if (result.isCancelled()) {
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Task::cancel(handle.lock());
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}
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else {
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Task::finish(handle.lock(), std::move(*std::move(result).getValue()));
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}
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},
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[handle](P progress) {
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Task::progress(handle.lock(), std::move(progress));
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},
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[handle]() -> bool {
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// The task has been cancelled if the user has explicitly cancelled it,
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// or if there is no one listening anymore
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auto lock = handle.lock();
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return !lock || lock->is(Status::Cancelled);
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}
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);
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|
}).detach();
|
|
return task;
|
|
}
|
|
/**
|
|
* Create a Task that waits for a list of other Tasks to finish, and then
|
|
* finishes with a list of their finish values
|
|
* @param tasks The tasks to wait for
|
|
* @param name The name of the Task; used for debugging
|
|
* @warning The result vector may contain nulls if any of the tasks
|
|
* were cancelled!
|
|
*/
|
|
template <std::move_constructible NP>
|
|
static Task<std::vector<T*>, std::monostate> all(std::vector<Task<T, NP>>&& tasks, std::string_view name = "<Multiple Tasks>") {
|
|
using AllTask = Task<std::vector<T*>, std::monostate>;
|
|
|
|
// If there are no tasks, return an immediate task that does nothing
|
|
if (tasks.empty()) {
|
|
return AllTask::immediate({}, name);
|
|
}
|
|
|
|
// Create a new supervising task for all of the provided tasks
|
|
auto task = AllTask(AllTask::Handle::create(name));
|
|
|
|
// Storage for storing the results received so far & keeping
|
|
// ownership of the running tasks
|
|
struct Waiting final {
|
|
std::vector<T*> taskResults;
|
|
std::vector<Task<std::monostate>> taskListeners;
|
|
size_t taskCount;
|
|
};
|
|
task.m_handle->m_extraData = std::make_unique<typename AllTask::Handle::ExtraData>(
|
|
// Create the data
|
|
static_cast<void*>(new Waiting()),
|
|
// When the task is destroyed
|
|
+[](void* ptr) {
|
|
delete static_cast<Waiting*>(ptr);
|
|
},
|
|
// If the task is cancelled
|
|
+[](void* ptr) {
|
|
// The move clears the `taskListeners` vector (important!)
|
|
for (auto task : std::move(static_cast<Waiting*>(ptr)->taskListeners)) {
|
|
task.cancel();
|
|
}
|
|
}
|
|
);
|
|
|
|
// Make sure the taskResults vector is large enough to fit all the
|
|
// results. By default, any cancelled Task becomes nullptr.
|
|
// Order of results must be preserved so when a Task finishes, it
|
|
// replaces the nullptr in the results vector at its place
|
|
static_cast<Waiting*>(task.m_handle->m_extraData->ptr)->taskResults.resize(tasks.size());
|
|
|
|
// Store the task count in case some tasks finish immediately during the loop
|
|
static_cast<Waiting*>(task.m_handle->m_extraData->ptr)->taskCount = tasks.size();
|
|
|
|
// Make sure to only give a weak pointer to avoid circular references!
|
|
// (Tasks should NEVER own themselves!!)
|
|
auto markAsDone = [handle = std::weak_ptr(task.m_handle)](size_t index, T* result) {
|
|
auto lock = handle.lock();
|
|
|
|
// If this task handle has expired, consider the task cancelled
|
|
// (We don't have to do anything because the lack of a handle
|
|
// means all the memory has been freed or is managed by
|
|
// something else)
|
|
if (!lock) return;
|
|
|
|
// Get the waiting handle from the task handle
|
|
auto waiting = static_cast<Waiting*>(lock->m_extraData->ptr);
|
|
|
|
// Mark the task as done by decrementing amount of tasks left
|
|
// (making sure not to underflow, even though that should 100%
|
|
// be impossible and if that happened something has gone
|
|
// extremely catastrophically wrong)
|
|
if (waiting->taskCount > 0) {
|
|
waiting->taskCount -= 1;
|
|
}
|
|
|
|
// SAFETY: The lifetime of result pointer is the same as the task that
|
|
// produced that pointer, so as long as we have an owning reference to
|
|
// the tasks through `taskListeners` we can be sure `result` is valid
|
|
waiting->taskResults[index] = result;
|
|
|
|
// If all tasks are done, finish
|
|
if (waiting->taskCount == 0) {
|
|
// SAFETY: The task results' lifetimes are tied to the tasks
|
|
// which could have their only owner be `waiting->taskListeners`,
|
|
// but since Waiting is owned by the returned AllTask it should
|
|
// be safe to access as long as it's accessible
|
|
AllTask::finish(lock, std::move(waiting->taskResults));
|
|
}
|
|
};
|
|
|
|
// Iterate the tasks & start listening to them using
|
|
size_t index = 0;
|
|
for (auto& taskToWait : tasks) {
|
|
static_cast<Waiting*>(task.m_handle->m_extraData->ptr)->taskListeners.emplace_back(taskToWait.map(
|
|
[index, markAsDone](auto* result) {
|
|
markAsDone(index, result);
|
|
return std::monostate();
|
|
},
|
|
[](auto*) { return std::monostate(); },
|
|
[index, markAsDone]() { markAsDone(index, nullptr); }
|
|
));
|
|
index += 1;
|
|
}
|
|
return task;
|
|
}
|
|
|
|
/**
|
|
* Create a new Task that listens to this Task and maps the values using
|
|
* the provided functions.
|
|
* The new Task takes (shared) ownership of this Task, so the new Task
|
|
* may very well be its only listener
|
|
* @param resultMapper Function that converts the finished values of
|
|
* the mapped Task to a desired type. Note that the function is only
|
|
* given a pointer to the finish value, as `T` is not guaranteed to be
|
|
* copyable - the mapper may NOT move out of the value!
|
|
* @param progressMapper Function that converts the progress values of
|
|
* the mapped Task to a desired type
|
|
* @param onCancelled Function that is called if the mapped Task is
|
|
* cancelled
|
|
* @param name The name of the Task; used for debugging. The name of
|
|
* the mapped task is appended to the end
|
|
*/
|
|
template <class ResultMapper, class ProgressMapper, class OnCancelled>
|
|
auto map(ResultMapper&& resultMapper, ProgressMapper&& progressMapper, OnCancelled&& onCancelled, std::string_view name = "<Mapping Task>") const {
|
|
using T2 = decltype(resultMapper(std::declval<T*>()));
|
|
using P2 = decltype(progressMapper(std::declval<P*>()));
|
|
|
|
static_assert(std::is_move_constructible_v<T2>, "The type being mapped to must be move-constructible!");
|
|
static_assert(std::is_move_constructible_v<P2>, "The type being mapped to must be move-constructible!");
|
|
|
|
Task<T2, P2> task = Task<T2, P2>::Handle::create(fmt::format("{} <= {}", name, m_handle->m_name));
|
|
|
|
// Lock the current task until we have managed to create our new one
|
|
std::unique_lock<std::recursive_mutex> lock(m_handle->m_mutex);
|
|
|
|
// If the current task is cancelled, cancel the new one immediately
|
|
if (m_handle->m_status == Status::Cancelled) {
|
|
onCancelled();
|
|
Task<T2, P2>::cancel(task.m_handle);
|
|
}
|
|
// If the current task is finished, immediately map the value and post that
|
|
else if (m_handle->m_status == Status::Finished) {
|
|
Task<T2, P2>::finish(task.m_handle, std::move(resultMapper(&*m_handle->m_resultValue)));
|
|
}
|
|
// Otherwise start listening and waiting for the current task to finish
|
|
else {
|
|
task.m_handle->m_extraData = std::make_unique<typename Task<T2, P2>::Handle::ExtraData>(
|
|
static_cast<void*>(new EventListener<Task>(
|
|
[
|
|
handle = std::weak_ptr(task.m_handle),
|
|
resultMapper = std::move(resultMapper),
|
|
progressMapper = std::move(progressMapper),
|
|
onCancelled = std::move(onCancelled)
|
|
](Event* event) mutable {
|
|
if (auto v = event->getValue()) {
|
|
Task<T2, P2>::finish(handle.lock(), std::move(resultMapper(v)));
|
|
}
|
|
else if (auto p = event->getProgress()) {
|
|
Task<T2, P2>::progress(handle.lock(), std::move(progressMapper(p)));
|
|
}
|
|
else if (event->isCancelled()) {
|
|
onCancelled();
|
|
Task<T2, P2>::cancel(handle.lock());
|
|
}
|
|
},
|
|
*this
|
|
)),
|
|
+[](void* ptr) {
|
|
delete static_cast<EventListener<Task>*>(ptr);
|
|
},
|
|
+[](void* ptr) {
|
|
// Cancel the mapped task too
|
|
static_cast<EventListener<Task>*>(ptr)->getFilter().cancel();
|
|
}
|
|
);
|
|
}
|
|
return task;
|
|
}
|
|
|
|
/**
|
|
* Create a new Task that listens to this Task and maps the values using
|
|
* the provided functions.
|
|
* The new Task takes (shared) ownership of this Task, so the new Task
|
|
* may very well be its only listener
|
|
* @param resultMapper Function that converts the finished values of
|
|
* the mapped Task to a desired type. Note that the function is only
|
|
* given a pointer to the finish value, as `T` is not guaranteed to be
|
|
* copyable - the mapper may NOT move out of the value!
|
|
* @param progressMapper Function that converts the progress values of
|
|
* the mapped Task to a desired type
|
|
* @param name The name of the Task; used for debugging. The name of
|
|
* the mapped task is appended to the end
|
|
*/ template <class ResultMapper, class ProgressMapper>
|
|
auto map(ResultMapper&& resultMapper, ProgressMapper&& progressMapper, std::string_view name = "<Mapping Task>") const {
|
|
return this->map(std::move(resultMapper), std::move(progressMapper), +[]() {}, name);
|
|
}
|
|
|
|
/**
|
|
* Create a new Task that listens to this Task and maps the finish value
|
|
* using the provided function. Progress is mapped by copy-constructing
|
|
* the value as-is.
|
|
* The new Task takes (shared) ownership of this Task, so the new Task
|
|
* may very well be its only listener
|
|
* @param resultMapper Function that converts the finished values of
|
|
* the mapped Task to a desired type. Note that the function is only
|
|
* given a pointer to the finish value, as `T` is not guaranteed to be
|
|
* copyable - the mapper may NOT move out of the value!
|
|
* @param name The name of the Task; used for debugging. The name of
|
|
* the mapped task is appended to the end
|
|
*/ template <class ResultMapper>
|
|
requires std::copy_constructible<P>
|
|
auto map(ResultMapper&& resultMapper, std::string_view name = "<Mapping Task>") const {
|
|
return this->map(std::move(resultMapper), +[](P* p) -> P { return *p; }, name);
|
|
}
|
|
|
|
/**
|
|
* Creates an implicit event listener for this Task that will call the
|
|
* provided functions when the Task finishes, progresses, or is cancelled.
|
|
* The listener will automatically be destroyed after the Task has finished.
|
|
* @param onResult Function to call when the Task finishes. The function
|
|
* is given a pointer to the finished value, `T*`.
|
|
* @param onProgress Function to call when the Task progresses. The function
|
|
* is given a pointer to the progress value, `P*`.
|
|
* @param onCancelled Function to call when the Task is cancelled
|
|
*
|
|
* @warning This method should only be used in a global context. If you rely
|
|
* on some node still existing when the task completes, use an event listener instead.
|
|
*/
|
|
template <class OnResult, class OnProgress, class OnCancelled>
|
|
void listen(OnResult&& onResult, OnProgress&& onProgress, OnCancelled&& onCancelled) const {
|
|
// use a raw pointer to avoid cyclic references,
|
|
// we destroy it manually later on
|
|
auto* listener = new EventListener<Task>(*this);
|
|
listener->bind([
|
|
onResult = std::move(onResult),
|
|
onProgress = std::move(onProgress),
|
|
onCancelled = std::move(onCancelled),
|
|
listener
|
|
](Event* event) mutable {
|
|
bool finished = false;
|
|
if (auto v = event->getValue()) {
|
|
finished = true;
|
|
onResult(v);
|
|
}
|
|
else if (auto p = event->getProgress()) {
|
|
onProgress(p);
|
|
}
|
|
else if (event->isCancelled()) {
|
|
finished = true;
|
|
onCancelled();
|
|
}
|
|
if (finished) {
|
|
// delay destroying the listener for a frame
|
|
// to prevent any potential use-after-free
|
|
queueInMainThread([listener] {
|
|
delete listener;
|
|
});
|
|
}
|
|
});
|
|
}
|
|
|
|
/**
|
|
* Creates an implicit event listener for this Task that will call the
|
|
* provided functions when the Task finishes or progresses.
|
|
* The listener will automatically be destroyed after the Task has finished.
|
|
* @param onResult Function to call when the Task finishes. The function
|
|
* is given a pointer to the finished value, `T*`.
|
|
* @param onProgress Function to call when the Task progresses. The function
|
|
* is given a pointer to the progress value, `P*`.
|
|
*
|
|
* @warning This method should only be used in a global context. If you rely
|
|
* on some node still existing when the task completes, use an event listener instead.
|
|
*/
|
|
template <class OnResult, class OnProgress>
|
|
void listen(OnResult&& onResult, OnProgress&& onProgress) const {
|
|
this->listen(std::move(onResult), std::move(onProgress), [] {});
|
|
}
|
|
|
|
/**
|
|
* Creates an implicit event listener for this Task that will call the
|
|
* provided function when the Task finishes.
|
|
* The listener will automatically be destroyed after the Task has finished.
|
|
* @param onResult Function to call when the Task finishes. The function
|
|
* is given a pointer to the finished value, `T*`.
|
|
*
|
|
* @warning This method should only be used in a global context. If you rely
|
|
* on some node still existing when the task completes, use an event listener instead.
|
|
*/
|
|
template <class OnResult>
|
|
void listen(OnResult&& onResult) const {
|
|
this->listen(std::move(onResult), [](auto const&) {}, [] {});
|
|
}
|
|
|
|
/**
|
|
* Create a new Task that listens to this Task and maps the values using
|
|
* the provided function. The new Task will only start when this Task finishes.
|
|
* @param mapper Function that makes a new task given the finished value of this task.
|
|
* The function signature should be `Task<NewType, NewProgress>(T*)`, and it will be executed
|
|
* on the main thread.
|
|
* @param name The name of the Task; used for debugging.
|
|
* @return The new Task that will run when this Task finishes.
|
|
* @note Progress from this task is not sent through, only progress from the new task is.
|
|
*/
|
|
template <std::invocable<T*> Mapper>
|
|
auto chain(Mapper mapper, std::string_view name = "<Chained Task>") const -> decltype(mapper(std::declval<T*>())) {
|
|
using NewTask = decltype(mapper(std::declval<T*>()));
|
|
using NewType = typename NewTask::Value;
|
|
using NewProgress = typename NewTask::Progress;
|
|
|
|
std::unique_lock<std::recursive_mutex> lock(m_handle->m_mutex);
|
|
|
|
if (m_handle->m_status == Status::Cancelled) {
|
|
// if the current task has been cancelled already, make an immediate cancelled task
|
|
return NewTask::cancelled();
|
|
}
|
|
else if (m_handle->m_status == Status::Finished) {
|
|
// if the current task is already done, we can just call the mapper directly
|
|
return mapper(&*m_handle->m_resultValue);
|
|
}
|
|
|
|
// otherwise, make a wrapper task that waits for the current task to finish,
|
|
// and then runs the mapper on the result. this new task will also wait for the task
|
|
// created by the mapper to finish, and will just forward the values through.
|
|
// do this because we cant really change the handle of the task we already returned
|
|
|
|
NewTask task = NewTask::Handle::create(fmt::format("{} <- {}", name, m_handle->m_name));
|
|
|
|
task.m_handle->m_extraData = std::make_unique<typename NewTask::Handle::ExtraData>(
|
|
// make the first event listener that waits for the current task
|
|
static_cast<void*>(new EventListener<Task>(
|
|
[handle = std::weak_ptr(task.m_handle), mapper = std::move(mapper)](Event* event) mutable {
|
|
if (auto v = event->getValue()) {
|
|
auto newInnerTask = mapper(v);
|
|
// this is scary.. but it doesn't seem to crash lol
|
|
handle.lock()->m_extraData = std::make_unique<typename NewTask::Handle::ExtraData>(
|
|
// make the second event listener that waits for the mapper's task
|
|
// and just forwards everything through
|
|
static_cast<void*>(new EventListener<NewTask>(
|
|
[handle](typename NewTask::Event* event) mutable {
|
|
if (auto v = event->getValue()) {
|
|
NewTask::finish(handle.lock(), std::move(*v));
|
|
}
|
|
else if (auto p = event->getProgress()) {
|
|
NewTask::progress(handle.lock(), std::move(*p));
|
|
}
|
|
else if (event->isCancelled()) {
|
|
NewTask::cancel(handle.lock());
|
|
}
|
|
},
|
|
std::move(newInnerTask)
|
|
)),
|
|
+[](void* ptr) {
|
|
delete static_cast<EventListener<NewTask>*>(ptr);
|
|
},
|
|
+[](void* ptr) {
|
|
static_cast<EventListener<NewTask>*>(ptr)->getFilter().cancel();
|
|
}
|
|
);
|
|
}
|
|
else if (auto p = event->getProgress()) {
|
|
// no guarantee P and NewProgress are compatible
|
|
// nor does it seem like the intended behavior?
|
|
// TODO: maybe add a mapper for progress?
|
|
}
|
|
else if (event->isCancelled()) {
|
|
NewTask::cancel(handle.lock());
|
|
}
|
|
},
|
|
*this
|
|
)),
|
|
+[](void* ptr) {
|
|
delete static_cast<EventListener<Task>*>(ptr);
|
|
},
|
|
+[](void* ptr) {
|
|
static_cast<EventListener<Task>*>(ptr)->getFilter().cancel();
|
|
}
|
|
);
|
|
return task;
|
|
}
|
|
|
|
ListenerResult handle(std::function<Callback> fn, Event* e) {
|
|
if (e->m_handle == m_handle && (!e->m_for || e->m_for == m_listener)) {
|
|
fn(e);
|
|
}
|
|
return ListenerResult::Propagate;
|
|
}
|
|
|
|
// todo: i believe alk wanted tasks to be in their own pool
|
|
EventListenerPool* getPool() const {
|
|
return DefaultEventListenerPool::get();
|
|
}
|
|
|
|
void setListener(EventListenerProtocol* listener) {
|
|
m_listener = listener;
|
|
|
|
if (!m_handle) return;
|
|
|
|
// If this task has already been finished and the finish event
|
|
// isn't pending in the event queue, immediately queue up a
|
|
// finish event for this listener
|
|
std::unique_lock<std::recursive_mutex> lock(m_handle->m_mutex);
|
|
if (m_handle->m_finalEventPosted) {
|
|
if (m_handle->m_status == Status::Finished) {
|
|
queueInMainThread([handle = m_handle, listener = m_listener, value = &*m_handle->m_resultValue]() {
|
|
auto ev = Event::createFinished(handle, value);
|
|
ev.m_for = listener;
|
|
ev.post();
|
|
});
|
|
}
|
|
else {
|
|
queueInMainThread([handle = m_handle, listener = m_listener]() {
|
|
auto ev = Event::createCancelled(handle);
|
|
ev.m_for = listener;
|
|
ev.post();
|
|
});
|
|
}
|
|
}
|
|
}
|
|
EventListenerProtocol* getListener() const {
|
|
return m_listener;
|
|
}
|
|
};
|
|
|
|
static_assert(is_filter<Task<int>>, "The Task class must be a valid event filter!");
|
|
}
|
|
|
|
// - C++20 coroutine support for Task - //
|
|
|
|
// Example usage (function must return a Task):
|
|
// ```
|
|
// Task<int> someTask() {
|
|
// auto response = co_await web::WebRequest().get("https://example.com");
|
|
// co_return response.code();
|
|
// }
|
|
// ```
|
|
// This will create a Task that will finish with the response code of the
|
|
// web request.
|
|
//
|
|
// Note: If the Task the coroutine is waiting on is cancelled, the coroutine
|
|
// will be destroyed and the Task will be cancelled as well. If the Task returned
|
|
// by the coroutine is cancelled, the coroutine will be destroyed as well and execution
|
|
// stops as soon as possible.
|
|
//
|
|
// The body of the coroutine is ran in whatever thread it got called in.
|
|
// TODO: maybe guarantee main thread?
|
|
//
|
|
// The coroutine can also yield progress values using `co_yield`:
|
|
// ```
|
|
// Task<std::string, int> someTask() {
|
|
// for (int i = 0; i < 10; i++) {
|
|
// co_yield i;
|
|
// }
|
|
// co_return "done!";
|
|
// }
|
|
// ```
|
|
|
|
namespace geode {
|
|
namespace geode_internal {
|
|
template <class T, class P>
|
|
struct TaskPromise {
|
|
using MyTask = Task<T, P>;
|
|
std::weak_ptr<typename MyTask::Handle> m_handle;
|
|
|
|
~TaskPromise() {
|
|
// does nothing if its not pending
|
|
MyTask::cancel(m_handle.lock());
|
|
}
|
|
|
|
std::suspend_never initial_suspend() noexcept { return {}; }
|
|
std::suspend_never final_suspend() noexcept { return {}; }
|
|
// TODO: do something here?
|
|
void unhandled_exception() {}
|
|
|
|
MyTask get_return_object() {
|
|
auto handle = MyTask::Handle::create("<Coroutine Task>");
|
|
m_handle = handle;
|
|
return handle;
|
|
}
|
|
|
|
void return_value(T x) {
|
|
MyTask::finish(m_handle.lock(), std::move(x));
|
|
}
|
|
|
|
std::suspend_never yield_value(P value) {
|
|
MyTask::progress(m_handle.lock(), std::move(value));
|
|
return {};
|
|
}
|
|
|
|
bool isCancelled() {
|
|
if (auto p = m_handle.lock()) {
|
|
return p->is(MyTask::Status::Cancelled);
|
|
}
|
|
return true;
|
|
}
|
|
};
|
|
|
|
template <class T, class P>
|
|
struct TaskAwaiter {
|
|
Task<T, P> task;
|
|
|
|
bool await_ready() {
|
|
return task.isFinished();
|
|
}
|
|
|
|
template <class U, class V>
|
|
void await_suspend(std::coroutine_handle<TaskPromise<U, V>> handle) {
|
|
if (handle.promise().isCancelled()) {
|
|
handle.destroy();
|
|
return;
|
|
}
|
|
// this should be fine because the parent task can only have
|
|
// one pending task at a time
|
|
auto parentHandle = handle.promise().m_handle.lock();
|
|
if (!parentHandle) {
|
|
handle.destroy();
|
|
return;
|
|
}
|
|
parentHandle->m_extraData = std::make_unique<typename Task<U, V>::Handle::ExtraData>(
|
|
static_cast<void*>(new EventListener<Task<T, P>>(
|
|
[handle](auto* event) {
|
|
if (event->getValue()) {
|
|
handle.resume();
|
|
}
|
|
if (event->isCancelled()) {
|
|
handle.destroy();
|
|
}
|
|
},
|
|
task
|
|
)),
|
|
+[](void* ptr) {
|
|
delete static_cast<EventListener<Task<T, P>>*>(ptr);
|
|
},
|
|
+[](void* ptr) {
|
|
static_cast<EventListener<Task<T, P>>*>(ptr)->getFilter().cancel();
|
|
}
|
|
);
|
|
}
|
|
|
|
T await_resume() {
|
|
return std::move(*task.getFinishedValue());
|
|
}
|
|
};
|
|
}
|
|
}
|
|
|
|
template <class T, class P>
|
|
auto operator co_await(geode::Task<T, P> task) {
|
|
return geode::geode_internal::TaskAwaiter<T, P>{task};
|
|
}
|
|
|
|
template <class T, class P, class... Args>
|
|
struct std::coroutine_traits<geode::Task<T, P>, Args...> {
|
|
using promise_type = geode::geode_internal::TaskPromise<T, P>;
|
|
};
|