|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
|
#ifndef FWCore_Concurrency_WaitingTask_h
#define FWCore_Concurrency_WaitingTask_h
// -*- C++ -*-
//
// Package: Concurrency
// Class : WaitingTask
//
/**\class WaitingTask WaitingTask.h FWCore/Concurrency/interface/WaitingTask.h
Description: Task used by WaitingTaskList.
Usage:
Used as a callback to happen after a task has been completed. Includes the ability to hold an exception which has occurred while waiting.
*/
//
// Original Author: Chris Jones
// Created: Thu Feb 21 13:46:31 CST 2013
// $Id$
//
// system include files
#include <atomic>
#include <exception>
#include <memory>
// user include files
#include "FWCore/Concurrency/interface/TaskBase.h"
// forward declarations
namespace edm {
class WaitingTaskList;
class WaitingTaskHolder;
class WaitingTaskWithArenaHolder;
class WaitingTask : public TaskBase {
public:
friend class WaitingTaskList;
friend class WaitingTaskHolder;
friend class WaitingTaskWithArenaHolder;
///Constructor
WaitingTask() noexcept : m_ptr{} {}
~WaitingTask() noexcept override {}
// ---------- const member functions ---------------------------
///Returns exception thrown by dependent task
/** If the value evalutes to true then the dependent task failed.
*/
std::exception_ptr exceptionPtr() const noexcept {
if (m_ptrSet == static_cast<unsigned char>(State::kSet)) {
return m_ptr;
}
return std::exception_ptr{};
}
protected:
std::exception_ptr const& uncheckedExceptionPtr() const noexcept { return m_ptr; }
private:
enum class State : unsigned char { kUnset = 0, kSetting = 1, kSet = 2 };
///Called if waited for task failed
/**Allows transfer of the exception caused by the dependent task to be
* moved to another thread.
* This method should only be called by WaitingTaskList
*/
void dependentTaskFailed(std::exception_ptr iPtr) noexcept {
unsigned char isSet = static_cast<unsigned char>(State::kUnset);
if (iPtr and m_ptrSet.compare_exchange_strong(isSet, static_cast<unsigned char>(State::kSetting))) {
m_ptr = iPtr;
m_ptrSet = static_cast<unsigned char>(State::kSet);
}
}
std::exception_ptr m_ptr;
std::atomic<unsigned char> m_ptrSet = static_cast<unsigned char>(State::kUnset);
};
template <typename F>
class FunctorWaitingTask : public WaitingTask {
public:
explicit FunctorWaitingTask(F f) : func_(std::move(f)) {}
void execute() final { func_(uncheckedExceptionPtr() ? &uncheckedExceptionPtr() : nullptr); };
private:
F func_;
};
template <typename F>
FunctorWaitingTask<F>* make_waiting_task(F f) {
return new FunctorWaitingTask<F>(std::move(f));
}
} // namespace edm
#endif
|