Fixed potential race condition where the ExecutiveProcess might send a notification message through cout while the OutputProcessor was busy using cout also. The result would be (at best) corrupted output. Now the ExecutiveProcess and the OutputProcessor both use OutputProcessor::sendString() which protects cout with a mutex.

git-svn-id: https://svn.microneil.com/svn/SNF4CGP/trunk@34 59e8e3e7-56fa-483b-b4b4-fa6ab0af3dfc

SNF4CGP/ExecutiveProcess.cpp

@@ -7,6 +7,8 @@
 #include "../CodeDweller/faults.hpp"
 
 #include <iostream>
+#include <string>
+#include <sstream>
 
 using namespace std;
 
@@ -62,6 +64,18 @@ void ExecutiveProcess::dispatchWakeupCommand() {
     dispatchCommand(C);                                                         // and dispatch a job with it.
 }
 
+void ExecutiveProcess::notifyQUIT() {
+    ostringstream O;
+    O << "* SNF4CGP[" << QuitJobNumber << "] Received QUIT, shutting down..." << endl;
+    Output.sendString(O.str());
+}
+
+void ExecutiveProcess::notifyNOTGOOD() {
+    ostringstream O;
+    O << "* SNF4CGP Input stream has gone bad, shutting down..." << endl;
+    Output.sendString(O.str());
+}
+
 void ExecutiveProcess::doProcessing() {                                         // Command processing happens here.
     dispatchWakeupCommand();                                                    // First job is to announce ourselves.
     for(;;) {                                                                   // Then process all jobs but QUIT.
@@ -70,19 +84,18 @@ void ExecutiveProcess::doProcessing() {
 
             case Command::QUIT: {
                 QuitJobNumber = C.Number;
-                cout << "* SNF4CGP[" << C.Number << "] Received QUIT, shutting down..." << endl;
-                cout.flush();
+                notifyQUIT();
                 return;
             }
 
             case Command::NOTGOOD: {
-                cout << "* SNF4CGP Input stream has gone bad, shutting down..." << endl;
-                cout.flush();
+                notifyNOTGOOD();
                 return;
             }
 
             default: {
                 dispatchCommand(C);
+                continue;
             }
         }
     }

SNF4CGP/ExecutiveProcess.hpp

@@ -41,6 +41,9 @@ class ExecutiveProcess {
     void dispatchCommand(Command& C);                                           // Job + Worker + Command; go!
     void dispatchWakeupCommand();
 
+    void notifyQUIT();
+    void notifyNOTGOOD();
+
   public:
 
     ExecutiveProcess(const string& Version, const string& Config);              // Simple construction. The d'tor needs

SNF4CGP/OutputProcessor.cpp

@@ -39,6 +39,12 @@ void OutputProcessor::outputJob(Job& J) {
     CompletedJobs.give(&J);
 }
 
+void OutputProcessor::sendString(const string& S) {                             // Safely send a string to cout.
+    ScopeMutex OneFlushAtATime(ProtectCout);
+    cout << S;
+    cout.flush();
+}
+
 void OutputProcessor::stop() {                                                  // Finish off the queue and quit.
     if(false == isTimeToStop) {                                                 // Do this only once.
         isTimeToStop = true;                                                    // Set the stop flag.
@@ -48,8 +54,7 @@ void OutputProcessor::stop() {
 
 void OutputProcessor::handleJob(Job& J) {                                       // Process a job.
     CurrentThreadState(PostingResponses);
-    cout << J.Responses();
-    cout.flush();
+    sendString(J.Responses());
     J.clear();
     RecycledJobs().drop(J);
 }

SNF4CGP/OutputProcessor.hpp

@@ -19,6 +19,8 @@ class Job;
 class OutputProcessor : private Thread {                                        // Process job outputs.
   private:
 
+    Mutex ProtectCout;
+
     JobPool* RecycledJobs_;                                                     // Where we put our recycled jobs.
     JobPool& RecycledJobs();                                                    // Safe access to jobs pool.
     ProductionQueue<Job*> CompletedJobs;                                        // Input queue for jobs to process.
@@ -35,6 +37,7 @@ class OutputProcessor : private Thread {
 
     void init(JobPool& J);                                                      // Start processing.
     void outputJob(Job& J);                                                     // Take this job and ... you know.
+    void sendString(const string& S);                                           // Safely send a string to cout.
     void stop();                                                                // Finish off the queue and quit.
 
     const static ThreadType Type;

SNF4CGP/main.cpp

@@ -13,7 +13,7 @@
 
 using namespace std;                                                            // Introduce standard namespace.
 
-const string SNF4CGP_VERSION_INFO = "SNF4CGP Version 0.0.2 Build: " __DATE__ " " __TIME__;
+const string SNF4CGP_VERSION_INFO = "SNF4CGP Version 0.0.3 Build: " __DATE__ " " __TIME__;
 
 const int ConfigPathArgNumber = 1;
 const int CorrectArgcNumber = 2;