Fix a race-condition when two games have been started simultaneously and attempt to create the same replay directory, refs #3255.

Instead of triggering a debug-breakpoint, print a warning to stdout and
succeed in the N'th retry when having started N processes
simultaneously.
Previously the problem had been addressed by using the processID in the
directory name.

This was SVN commit r17776.

source/lib/file/file_system.cpp

@@ -130,7 +130,7 @@ Status GetDirectoryEntries(const OsPath& path, CFileInfos* files, DirectoryNames
 }
 
 
-Status CreateDirectories(const OsPath& path, mode_t mode)
+Status CreateDirectories(const OsPath& path, mode_t mode, bool breakpoint)
 {
 	if(path.empty())
 		return INFO::OK;
@@ -146,7 +146,7 @@ Status CreateDirectories(const OsPath& path, mode_t mode)
 	// If we were passed a path ending with '/', strip the '/' now so that
 	// we can consistently use Parent to find parent directory names
 	if(path.IsDirectory())
-		return CreateDirectories(path.Parent(), mode);
+		return CreateDirectories(path.Parent(), mode, breakpoint);
 
 	RETURN_STATUS_IF_ERR(CreateDirectories(path.Parent(), mode));
 
@@ -154,7 +154,10 @@ Status CreateDirectories(const OsPath& path, mode_t mode)
 	if(wmkdir(path, mode) != 0)
 	{
 		debug_printf("CreateDirectories: failed to mkdir %s (mode %d)\n", path.string8().c_str(), mode);
-		WARN_RETURN(StatusFromErrno());
+		if (breakpoint)
+			WARN_RETURN(StatusFromErrno());
+		else
+			return StatusFromErrno();
 	}
 
 	return INFO::OK;

source/lib/file/file_system.h

@@ -80,7 +80,7 @@ LIB_API Status GetDirectoryEntries(const OsPath& path, CFileInfos* files, Direct
 
 // same as boost::filesystem::create_directories, except that mkdir is invoked with
 // <mode> instead of 0755.
-LIB_API Status CreateDirectories(const OsPath& path, mode_t mode);
+LIB_API Status CreateDirectories(const OsPath& path, mode_t mode, bool breakpoint = true);
 
 LIB_API Status DeleteDirectory(const OsPath& dirPath);
 

source/ps/Replay.cpp

@@ -72,7 +72,6 @@ void CReplayLogger::StartGame(JS::MutableHandleValue attribs)
 
 	m_Directory = getDateIndexSubdirectory(VisualReplay::GetDirectoryName());
 	debug_printf("Writing replay to %s\n", m_Directory.string8().c_str());
-	CreateDirectories(m_Directory, 0700);
 
 	m_Stream = new std::ofstream(OsString(m_Directory / L"commands.txt").c_str(), std::ofstream::out | std::ofstream::trunc);
 	*m_Stream << "start " << m_ScriptInterface.StringifyJSON(attribs, false) << "\n";

source/ps/Util.cpp

@@ -201,6 +201,10 @@ OsPath getDateIndexSubdirectory(const OsPath& parentDir)
     const std::time_t timestamp = std::time(nullptr);
     const struct std::tm* now = std::localtime(&timestamp);
 
+	// Two processes executing this simultaneously might attempt to create the same directory.
+	int tries = 0;
+	const int maxTries = 10;
+
 	int i = 0;
 	OsPath path;
 	char directory[256];
@@ -209,7 +213,14 @@ OsPath getDateIndexSubdirectory(const OsPath& parentDir)
 	{
 		sprintf(directory, "%04d-%02d-%02d_%04d", now->tm_year+1900, now->tm_mon+1, now->tm_mday, ++i);
 		path = parentDir / CStr(directory);
-	} while (DirectoryExists(path) || FileExists(path));
+
+		if (DirectoryExists(path) || FileExists(path))
+			continue;
+
+		if (CreateDirectories(path, 0700, ++tries > maxTries) == INFO::OK)
+			break;
+
+	} while(tries <= maxTries);
 
 	return path;
 }

source/simulation2/Simulation2.cpp

@@ -298,7 +298,6 @@ void CSimulation2Impl::ReportSerializationFailure(
 {
 	const OsPath path = getDateIndexSubdirectory(psLogDir() / "serializationtest");
 	debug_printf("Writing serializationtest-data to %s\n", path.string8().c_str());
-	CreateDirectories(path, 0700);
 
 	// Clean up obsolete files from previous runs
 	wunlink(path / "hash.before.a");
@@ -554,7 +553,6 @@ void CSimulation2Impl::DumpState()
 	std::stringstream name;\
 	name << std::setw(5) << std::setfill('0') << m_TurnNumber << ".txt";
 	const OsPath path = m_OOSLogPath / name.str();
-	CreateDirectories(path.Parent(), 0700);
 	std::ofstream file (OsString(path).c_str(), std::ofstream::out | std::ofstream::trunc);
 
 	file << "State hash: " << std::hex;