closes #571 Removed global lock at dispatch

CHANGELOG.md

@@ -2,10 +2,11 @@
 
 ## [Unreleased]
 ### Fixes
-- Build fix for kFreeBSD as suggested in issue 563
+ - Build fix for kFreeBSD as suggested in issue #563
+ - Fixed issue with deadlock on dispatch (see #571)
 
 ### Updates
-- Added support for AIX (thanks to @apollo13)
+ - Added support for AIX (thanks to @apollo13)
 
 ## [9.95.0] - 02-08-2017
 ### Added

samples/STL/multi-loggers-with-async.cpp

@@ -0,0 +1,51 @@
+//
+// This file is part of Easylogging++ samples
+//
+// Revision 1.0
+//
+
+#include <chrono>
+#include <thread>
+#include <future>
+#include "easylogging++.h"
+
+INITIALIZE_EASYLOGGINGPP
+
+void f() {
+    std::async(std::launch::async, [&]() {
+        std::cout << "[internal] inside async()" << std::endl;
+        std::this_thread::sleep_for(std::chrono::seconds(1));
+        LOG(INFO) << "This is from async";
+    });
+}
+
+class MyHandler : public el::LogDispatchCallback {
+public:
+    void handle(const el::LogDispatchData* d) {
+        std::cout << "Message: " << d->logMessage()->message() << " [logger: " << d->logMessage()->logger()->id() << "]" << std::endl;
+        if (d->logMessage()->logger()->id() != "default") {
+            std::cout << "[internal] calling f()" << std::endl;
+            f();
+        }
+    }
+};
+
+
+
+int main(int,char**){
+    el::Loggers::addFlag(el::LoggingFlag::CreateLoggerAutomatically);
+//    el::Helpers::uninstallLogDispatchCallback<el::base::DefaultLogDispatchCallback>("DefaultLogDispatchCallback");
+    el::Helpers::installLogDispatchCallback<MyHandler>("MyHandler");
+
+    LOG(INFO)<<"The program has started!";
+    CLOG(INFO, "frommain") << "THis is another";
+
+    std::thread t1([](){
+        LOG(INFO) << "This is from thread";
+    });
+
+    t1.join();
+
+    LOG(INFO) << "Shutting down.";
+    return 0;
+}

src/easylogging++.cc

@@ -2368,7 +2368,6 @@ void LogDispatcher::dispatch(void) {
   if (!m_proceed) {
     return;
   }
-  base::threading::ScopedLock scopedLock(ELPP->lock());
   base::TypedConfigurations* tc = m_logMessage.logger()->m_typedConfigurations;
   if (ELPP->hasFlag(LoggingFlag::StrictLogFileSizeCheck)) {
     tc->validateFileRolling(m_logMessage.level(), ELPP->preRollOutCallback());
@@ -2444,12 +2443,13 @@ void Writer::initializeLogger(const std::string& loggerId, bool lookup, bool nee
     m_logger = ELPP->registeredLoggers()->get(loggerId, ELPP->hasFlag(LoggingFlag::CreateLoggerAutomatically));
   }
   if (m_logger == nullptr) {
-    ELPP->acquireLock();
-    if (!ELPP->registeredLoggers()->has(std::string(base::consts::kDefaultLoggerId))) {
-      // Somehow default logger has been unregistered. Not good! Register again
-      ELPP->registeredLoggers()->get(std::string(base::consts::kDefaultLoggerId));
+    {
+        base::threading::ScopedLock scopedLock(ELPP->lock());
+        if (!ELPP->registeredLoggers()->has(std::string(base::consts::kDefaultLoggerId))) {
+            // Somehow default logger has been unregistered. Not good! Register again
+            ELPP->registeredLoggers()->get(std::string(base::consts::kDefaultLoggerId));
+        }
     }
-    ELPP->releaseLock();  // Need to unlock it for next writer
     Writer(Level::Debug, m_file, m_line, m_func).construct(1, base::consts::kDefaultLoggerId)
         << "Logger [" << loggerId << "] is not registered yet!";
     m_proceed = false;