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-rw-r--r--src/scheduler.cpp102
1 files changed, 102 insertions, 0 deletions
diff --git a/src/scheduler.cpp b/src/scheduler.cpp
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+// Copyright (c) 2015 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "scheduler.h"
+
+#include <assert.h>
+#include <boost/bind.hpp>
+#include <utility>
+
+CScheduler::CScheduler() : nThreadsServicingQueue(0)
+{
+}
+
+CScheduler::~CScheduler()
+{
+ assert(nThreadsServicingQueue == 0);
+}
+
+
+#if BOOST_VERSION < 105000
+static boost::system_time toPosixTime(const boost::chrono::system_clock::time_point& t)
+{
+ boost::chrono::system_clock::duration d = t.time_since_epoch();
+ boost::chrono::microseconds usecs = boost::chrono::duration_cast<boost::chrono::microseconds>(d);
+ boost::system_time result = boost::posix_time::from_time_t(0) +
+ boost::posix_time::microseconds(usecs.count());
+ return result;
+}
+#endif
+
+void CScheduler::serviceQueue()
+{
+ boost::unique_lock<boost::mutex> lock(newTaskMutex);
+ ++nThreadsServicingQueue;
+
+ // newTaskMutex is locked throughout this loop EXCEPT
+ // when the thread is waiting or when the user's function
+ // is called.
+ while (1) {
+ try {
+ while (taskQueue.empty()) {
+ // Wait until there is something to do.
+ newTaskScheduled.wait(lock);
+ }
+// Wait until either there is a new task, or until
+// the time of the first item on the queue:
+
+// wait_until needs boost 1.50 or later; older versions have timed_wait:
+#if BOOST_VERSION < 105000
+ while (!taskQueue.empty() && newTaskScheduled.timed_wait(lock, toPosixTime(taskQueue.begin()->first))) {
+ // Keep waiting until timeout
+ }
+#else
+ while (!taskQueue.empty() && newTaskScheduled.wait_until(lock, taskQueue.begin()->first) != boost::cv_status::timeout) {
+ // Keep waiting until timeout
+ }
+#endif
+ // If there are multiple threads, the queue can empty while we're waiting (another
+ // thread may service the task we were waiting on).
+ if (taskQueue.empty())
+ continue;
+
+ Function f = taskQueue.begin()->second;
+ taskQueue.erase(taskQueue.begin());
+
+ // Unlock before calling f, so it can reschedule itself or another task
+ // without deadlocking:
+ lock.unlock();
+ f();
+ lock.lock();
+ } catch (...) {
+ --nThreadsServicingQueue;
+ throw;
+ }
+ }
+}
+
+void CScheduler::schedule(CScheduler::Function f, boost::chrono::system_clock::time_point t)
+{
+ {
+ boost::unique_lock<boost::mutex> lock(newTaskMutex);
+ taskQueue.insert(std::make_pair(t, f));
+ }
+ newTaskScheduled.notify_one();
+}
+
+void CScheduler::scheduleFromNow(CScheduler::Function f, int64_t deltaSeconds)
+{
+ schedule(f, boost::chrono::system_clock::now() + boost::chrono::seconds(deltaSeconds));
+}
+
+static void Repeat(CScheduler* s, CScheduler::Function f, int64_t deltaSeconds)
+{
+ f();
+ s->scheduleFromNow(boost::bind(&Repeat, s, f, deltaSeconds), deltaSeconds);
+}
+
+void CScheduler::scheduleEvery(CScheduler::Function f, int64_t deltaSeconds)
+{
+ scheduleFromNow(boost::bind(&Repeat, this, f, deltaSeconds), deltaSeconds);
+}