--- /dev/null
+#ifndef SIMGRID_S4U_TASK_H_
+#define SIMGRID_S4U_TASK_H_
+
+#include <simgrid/s4u/Activity.hpp>
+#include <simgrid/s4u/Io.hpp>
+#include <xbt/Extendable.hpp>
+
+#include <atomic>
+#include <deque>
+#include <map>
+#include <memory>
+#include <set>
+
+namespace simgrid::s4u {
+
+class Task;
+using TaskPtr = boost::intrusive_ptr<Task>;
+XBT_PUBLIC void intrusive_ptr_release(Task* o);
+XBT_PUBLIC void intrusive_ptr_add_ref(Task* o);
+class ExecTask;
+using ExecTaskPtr = boost::intrusive_ptr<ExecTask>;
+class CommTask;
+using CommTaskPtr = boost::intrusive_ptr<CommTask>;
+class IoTask;
+using IoTaskPtr = boost::intrusive_ptr<IoTask>;
+
+class XBT_PUBLIC Token : public xbt::Extendable<Token> {};
+
+class Task {
+ std::string name_;
+ double amount_;
+ int queued_firings_ = 0;
+ int count_ = 0;
+ bool working_ = false;
+
+ std::set<Task*> successors_ = {};
+ std::map<Task*, unsigned int> predecessors_ = {};
+ std::atomic_int_fast32_t refcount_{0};
+
+ bool ready_to_run() const;
+ void receive(Task* source);
+
+ std::shared_ptr<Token> token_ = nullptr;
+ std::deque<std::map<TaskPtr, std::shared_ptr<Token>>> tokens_received_;
+ ActivityPtr previous_activity_;
+ ActivityPtr current_activity_;
+
+protected:
+ explicit Task(const std::string& name);
+ virtual ~Task() = default;
+
+ virtual void fire();
+ void complete();
+
+ void set_current_activity(ActivityPtr a) { current_activity_ = a; }
+
+ inline static xbt::signal<void(Task*)> on_start;
+ xbt::signal<void(Task*)> on_this_start;
+ inline static xbt::signal<void(Task*)> on_completion;
+ xbt::signal<void(Task*)> on_this_completion;
+
+public:
+ const std::string& get_name() const { return name_; }
+ const char* get_cname() const { return name_.c_str(); }
+ void set_amount(double amount);
+ double get_amount() const { return amount_; }
+ int get_count() const { return count_; }
+
+ void set_token(std::shared_ptr<Token> token);
+ std::shared_ptr<Token> get_next_token_from(TaskPtr t);
+
+ void add_successor(TaskPtr t);
+ void remove_successor(TaskPtr t);
+ void remove_all_successors();
+ const std::set<Task*>& get_successors() const { return successors_; }
+
+ void enqueue_firings(int n);
+
+ /** Add a callback fired before this task activity starts */
+ void on_this_start_cb(const std::function<void(Task*)>& func) { on_this_start.connect(func); }
+ /** Add a callback fired before a task activity starts.
+ * Triggered after the on_this_start function**/
+ static void on_start_cb(const std::function<void(Task*)>& cb) { on_start.connect(cb); }
+ /** Add a callback fired before this task activity ends */
+ void on_this_completion_cb(const std::function<void(Task*)>& func) { on_this_completion.connect(func); };
+ /** Add a callback fired after a task activity ends.
+ * Triggered after the on_this_end function, but before sending tokens to successors.**/
+ static void on_completion_cb(const std::function<void(Task*)>& cb) { on_completion.connect(cb); }
+
+#ifndef DOXYGEN
+ friend void intrusive_ptr_release(Task* o)
+ {
+ if (o->refcount_.fetch_sub(1, std::memory_order_release) == 1) {
+ std::atomic_thread_fence(std::memory_order_acquire);
+ delete o;
+ }
+ }
+ friend void intrusive_ptr_add_ref(Task* o) { o->refcount_.fetch_add(1, std::memory_order_relaxed); }
+#endif
+};
+
+class CommTask : public Task {
+ Host* source_;
+ Host* destination_;
+
+ explicit CommTask(const std::string& name);
+ void fire() override;
+
+public:
+ static CommTaskPtr init(const std::string& name);
+ static CommTaskPtr init(const std::string& name, double bytes, Host* source, Host* destination);
+
+ CommTaskPtr set_source(Host* source);
+ Host* get_source() const { return source_; }
+ CommTaskPtr set_destination(Host* destination);
+ Host* get_destination() const { return destination_; }
+ CommTaskPtr set_bytes(double bytes);
+ double get_bytes() const { return get_amount(); }
+};
+
+class ExecTask : public Task {
+ Host* host_;
+
+ explicit ExecTask(const std::string& name);
+ void fire() override;
+
+public:
+ static ExecTaskPtr init(const std::string& name);
+ static ExecTaskPtr init(const std::string& name, double flops, Host* host);
+
+ ExecTaskPtr set_host(Host* host);
+ Host* get_host() const { return host_; }
+ ExecTaskPtr set_flops(double flops);
+ double get_flops() const { return get_amount(); }
+};
+
+class IoTask : public Task {
+ Disk* disk_;
+ Io::OpType type_;
+ explicit IoTask(const std::string& name);
+ void fire() override;
+
+public:
+ static IoTaskPtr init(const std::string& name);
+ static IoTaskPtr init(const std::string& name, double bytes, Disk* disk, Io::OpType type);
+
+ IoTaskPtr set_disk(Disk* disk);
+ Disk* get_disk() const { return disk_; }
+ IoTaskPtr set_bytes(double bytes);
+ double get_bytes() const { return get_amount(); }
+ IoTaskPtr set_op_type(Io::OpType type);
+ Io::OpType get_op_type() const { return type_; }
+};
+} // namespace simgrid::s4u
+#endif
