Use system wide file locks to synchronize log files.

The global semaphore has been observed to not be released on unix like
platforms when the process exits. So, we convert to file locks, which
will be released on process exit on unix like platforms. Unfortunately,
Win32 file locks and POSIX file locks have slightly different semantics
in that Win32 locks are mandatory and POSIX locks are advisory, which
can result in slightly different behavior. OTOH, this should fix the
client deadlocking until the system is restarted, so this should be an
overall win.

Sources/Plasma/CoreLib/CMakeLists.txt

@@ -6,6 +6,7 @@ set(CoreLib_SOURCES
     hsExceptions.cpp
     hsExceptionStack.cpp
     hsFastMath.cpp
+    hsFILELock.cpp
     hsGeometry3.cpp
     hsMatrix33.cpp
     hsMatrix44.cpp
@@ -43,6 +44,7 @@ set(CoreLib_HEADERS
     hsExceptions.h
     hsExceptionStack.h
     hsFastMath.h
+    hsFILELock.h
     hsGeometry3.h
     hsLockGuard.h
     hsMatrix44.h

Sources/Plasma/PubUtilLib/plStatusLog/plStatusLog.cpp

@@ -58,6 +58,7 @@ You can contact Cyan Worlds, Inc. by email legal@cyan.com
 #include "plStatusLog.h"
 #include "plEncryptLogLine.h"
 
+#include "hsFILELock.h"
 #include "plProduct.h"
 #include "hsThread.h"
 #include "hsTimer.h"
@@ -259,20 +260,17 @@ bool plStatusLogMgr::DumpLogs( const plFileName &newFolderName )
 uint32_t plStatusLog::fLoggingOff = false;
 
 plStatusLog::plStatusLog( uint8_t numDisplayLines, const plFileName &filename, uint32_t flags )
-    : fFileHandle(), fSema(), fSize(), fForceLog(), fMaxNumLines(numDisplayLines),
+    : fFileHandle(), fSize(), fForceLog(), fMaxNumLines(numDisplayLines),
       fDisplayPointer()
 {
     if (filename.IsValid())
     {
         fFilename = filename;
-        fSema = new hsGlobalSemaphore(1, fFilename.AsString().c_str());
     }
     else
     {
         fFilename = "";
         flags |= kDontWriteFile;
-
-        fSema = new hsGlobalSemaphore(1);
     }
 
     fOrigFlags = fFlags = flags;
@@ -366,9 +364,6 @@ void    plStatusLog::IFini()
     if (fBack != nullptr || fNext != nullptr)
         IUnlink();
 
-    if (fSema)
-        delete fSema;
-
     delete [] fLines;
     delete [] fColors;
 }
@@ -431,7 +426,8 @@ bool plStatusLog::IAddLine(const ST::string& line, uint32_t color)
         return true;
 
     /// Scroll pointers up
-    fSema->Wait();
+    hsFILELock fileLock(fFileHandle);
+    hsLockGuard(fileLock);
 
     if (fMaxNumLines > 0)
     {
@@ -448,8 +444,6 @@ bool plStatusLog::IAddLine(const ST::string& line, uint32_t color)
 
     bool ret = IPrintLineToFile(line);
 
-    fSema->Signal();
-
     return ret;
 }
 

Sources/Plasma/PubUtilLib/plStatusLog/plStatusLog.h

@@ -57,7 +57,6 @@ You can contact Cyan Worlds, Inc. by email legal@cyan.com
 #define _plStatusLog_h
 
 #include "HeadSpin.h"
-#include "hsThread.h"
 #include "plFileSystem.h"
 #include "plLoggable.h"
 
@@ -88,7 +87,6 @@ class plStatusLog : public plLog
         plFileName   fFilename;
         ST::string*  fLines;
         uint32_t*    fColors;
-        hsGlobalSemaphore* fSema;
         FILE*        fFileHandle;
         uint32_t     fSize;
         bool         fForceLog;