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
|
#include "Executor.h"
#include "utils/finally.h"
namespace executor {
namespace {
thread_local Executor* currentExecutorRef = nullptr;
}
Executor* currentExecutor() { return currentExecutorRef; }
void Executor::post(Executor::Callback cb)
{
// To avoid deadlocks or recusive mutexes we have a temporary list which contains work items not added to the queue
// yet. Those items will be transferred to the main queue in the next process call.
std::unique_lock<std::mutex> lock(m_pendingWorkItemsMutex);
m_pendingWorkItems.push_back(std::move(cb));
}
void Executor::process()
{
// Ensure that no deadlocks happen when this is called from multiple threads
std::lock(m_mainMutex, m_pendingWorkItemsMutex);
Assertion(currentExecutorRef == nullptr, "Executor is already processing! Only one is allowed at a time.");
currentExecutorRef = this;
// Clean up ref after this function
auto _ = util::finally([]() { currentExecutorRef = nullptr; });
std::lock_guard<std::mutex> lk1(m_mainMutex, std::adopt_lock);
{
// Only need this for a limited time so we do this in a separate scope
std::lock_guard<std::mutex> lk2(m_pendingWorkItemsMutex, std::adopt_lock);
// Now move the pending items over to the actual work list
std::move(m_pendingWorkItems.begin(), m_pendingWorkItems.end(), std::back_inserter(m_workItems));
m_pendingWorkItems.clear();
}
for (auto iter = m_workItems.begin(); iter != m_workItems.end();) {
auto& cb = *iter;
if (cb() == CallbackResult::Done) {
// This callback does not want to be called again
// if we're sitting on the very last work item, popping-back will invalidate the iterator!
if (iter + 1 == m_workItems.end()) {
m_workItems.pop_back();
break;
}
// Remove entry without copying it since the current iterator value is not needed anymore
std::iter_swap(iter, std::prev(m_workItems.end()));
m_workItems.pop_back();
continue;
}
// next particle
++iter;
}
}
} // namespace executor
|
