net: add CThreadInterrupt and InterruptibleSleep

CMakeLists.txt

@@ -416,6 +416,7 @@ set(UTIL_SOURCES
         ./src/random.cpp
         ./src/rpc/protocol.cpp
         ./src/sync.cpp
+        ./src/threadinterrupt.cpp
         ./src/blob_uint256.cpp
         ./src/arith_uint256.cpp
         ./src/uint256.cpp

src/Makefile.am

@@ -244,6 +244,7 @@ BITCOIN_CORE_H = \
   support/cleanse.h \
   sync.h \
   threadsafety.h \
+  threadinterrupt.h \
   timedata.h \
   tinyformat.h \
   torcontrol.h \
@@ -513,6 +514,7 @@ libbitcoin_util_a_SOURCES = \
   rpc/protocol.cpp \
   support/cleanse.cpp \
   sync.cpp \
+  threadinterrupt.cpp \
   uint256.cpp \
   blob_uint256.cpp \
   util.cpp \

src/threadinterrupt.cpp

@@ -0,0 +1,41 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2016 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 "threadinterrupt.h"
+
+CThreadInterrupt::operator bool() const
+{
+    return flag.load(std::memory_order_acquire);
+}
+
+void CThreadInterrupt::reset()
+{
+    flag.store(false, std::memory_order_release);
+}
+
+void CThreadInterrupt::operator()()
+{
+    {
+        std::unique_lock<std::mutex> lock(mut);
+        flag.store(true, std::memory_order_release);
+    }
+    cond.notify_all();
+}
+
+bool CThreadInterrupt::sleep_for(std::chrono::milliseconds rel_time)
+{
+    std::unique_lock<std::mutex> lock(mut);
+    return !cond.wait_for(lock, rel_time, [this]() { return flag.load(std::memory_order_acquire); });
+}
+
+bool CThreadInterrupt::sleep_for(std::chrono::seconds rel_time)
+{
+    return sleep_for(std::chrono::duration_cast<std::chrono::milliseconds>(rel_time));
+}
+
+bool CThreadInterrupt::sleep_for(std::chrono::minutes rel_time)
+{
+    return sleep_for(std::chrono::duration_cast<std::chrono::milliseconds>(rel_time));
+}

src/threadinterrupt.h

@@ -0,0 +1,34 @@
+// Copyright (c) 2016 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_THREADINTERRUPT_H
+#define BITCOIN_THREADINTERRUPT_H
+
+#include <atomic>
+#include <chrono>
+#include <condition_variable>
+#include <mutex>
+
+/*
+    A helper class for interruptible sleeps. Calling operator() will interrupt
+    any current sleep, and after that point operator bool() will return true
+    until reset.
+*/
+class CThreadInterrupt
+{
+public:
+    explicit operator bool() const;
+    void operator()();
+    void reset();
+    bool sleep_for(std::chrono::milliseconds rel_time);
+    bool sleep_for(std::chrono::seconds rel_time);
+    bool sleep_for(std::chrono::minutes rel_time);
+
+private:
+    std::condition_variable cond;
+    std::mutex mut;
+    std::atomic<bool> flag;
+};
+
+#endif //BITCOIN_THREADINTERRUPT_H