Modify CacheMap to avoid race conditions

lib/inc/drogon/CacheMap.h

@@ -110,11 +110,7 @@ public:
     };
     ~CacheMap(){
         _loop->invalidateTimer(_timerId);
-        std::lock_guard<std::mutex> lock(bucketMutex_);
-        for(auto & queue : _wheels)
-        {
-            queue.clear();
-        }
+        LOG_TRACE<<"CacheMap destruct!";
     }
     typedef struct MapValue
     {
@@ -209,7 +205,7 @@ private:
     size_t _bucketsNumPerWheel;
 
 
-    void inertEntry(size_t delay,CallbackEntryPtr entryPtr)
+    void insertEntry(size_t delay,CallbackEntryPtr entryPtr)
     {
         //protected by bucketMutex;
         if(delay<=0)
@@ -256,7 +252,7 @@ private:
         if(entryPtr)
         {
             std::lock_guard<std::mutex> lock(bucketMutex_);
-            inertEntry(delay,entryPtr);
+            insertEntry(delay,entryPtr);
         }
         else
         {
@@ -265,7 +261,10 @@ private:
                 if(_map.find(key)!=_map.end())
                 {
                     auto & value=_map[key];
-                    if(value.timeout>0)
+                    auto entryPtr=value._weakEntryPtr.lock();
+                    //entryPtr is used to avoid race conditions
+                    if(value.timeout>0&&
+                       !entryPtr)
                     {
                         if(value._timeoutCallback)
                         {
@@ -282,7 +281,7 @@ private:
 
             {
                 std::lock_guard<std::mutex> lock(bucketMutex_);
-                inertEntry(delay,entryPtr);
+                insertEntry(delay,entryPtr);
             }
         }
     }

tests/CMakeLists.txt

@@ -3,6 +3,7 @@ if(OpenSSL_FOUND)
 link_libraries(ssl crypto)
 endif()
 add_executable(cache_map_test CacheMapTest.cc)
+add_executable(cache_map_test2 CacheMapTest2.cc)
 add_executable(cookies_test CookiesTest.cc)
 add_executable(class_name_test ClassNameTest.cc)
 add_executable(sha1_test Sha1Test.cc)

tests/CacheMapTest2.cc

@@ -0,0 +1,52 @@
+#include <drogon/CacheMap.h>
+#include <trantor/utils/Logger.h>
+#include <trantor/net/EventLoopThread.h>
+#include <drogon/utils/Utilities.h>
+#include <unistd.h>
+#include <string>
+#include <thread>
+#include <iostream>
+#include <memory>
+
+int main()
+{
+
+        trantor::Logger::setLogLevel(trantor::Logger::TRACE);
+        trantor::EventLoopThread loopThread;
+        loopThread.run();
+
+
+
+        auto loop=loopThread.getLoop();
+        std::shared_ptr<drogon::CacheMap<std::string,std::string>> main_cachePtr;
+        auto now=trantor::Date::date();
+        loop->runAt(now.after(1).roundSecond(),[=,&main_cachePtr]()
+        {
+            std::shared_ptr<drogon::CacheMap<std::string,std::string>> cachePtr
+                    =std::make_shared<drogon::CacheMap<std::string,std::string>>
+                            (loop,1,3,3);
+            main_cachePtr=cachePtr;
+            LOG_DEBUG<<"insert :usecount="<<main_cachePtr.use_count();
+            cachePtr->insert("1","1",3,[=](){
+                LOG_DEBUG<<"timeout!erase 1!";
+            });
+            cachePtr->insert("2","2",10,[](){
+                LOG_DEBUG<<"2 timeout";
+            });
+        });
+        trantor::EventLoop mainLoop;
+        mainLoop.runAt(now.after(3).roundSecond().after(0.0013),[&](){
+            if(main_cachePtr->find("1"))
+            {
+                LOG_DEBUG<<"find item 1";
+            }
+            else
+            {
+                LOG_DEBUG<<"can't find item 1";
+            }
+        });
+        mainLoop.runAfter(8,[&](){
+            mainLoop.quit();
+        });
+        mainLoop.loop();
+}

trantor

@@ -1 +1 @@
-Subproject commit 17ad9d0c8bcb69b357443f42a976c9530acbc283
+Subproject commit 9fe1163f535ec8a229a8a37cc059e1b500bde51c