Box Backup 0.09 with a few tweeks

1 files changed, 144 insertions, 0 deletions

diff --git a/lib/common/NamedLock.cpp b/lib/common/NamedLock.cpp
new file mode 100755
index 00000000..1f6e038a
--- /dev/null
+++ b/lib/common/NamedLock.cpp
@@ -0,0 +1,144 @@
+// --------------------------------------------------------------------------
+//
+// File
+//		Name:    NamedLock.cpp
+//		Purpose: A global named lock, implemented as a lock file in file system
+//		Created: 2003/08/28
+//
+// --------------------------------------------------------------------------
+
+#include "Box.h"
+
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+#ifdef PLATFORM_LINUX
+	#include <sys/file.h>
+#endif // PLATFORM_LINUX
+#ifdef PLATFORM_CYGWIN
+	#include <sys/file.h>
+#endif // PLATFORM_CYGWIN
+
+#include "NamedLock.h"
+#include "CommonException.h"
+
+#include "MemLeakFindOn.h"
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    NamedLock::NamedLock()
+//		Purpose: Constructor
+//		Created: 2003/08/28
+//
+// --------------------------------------------------------------------------
+NamedLock::NamedLock()
+	: mFileDescriptor(-1)
+{
+}
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    NamedLock::~NamedLock()
+//		Purpose: Destructor (automatically unlocks if locked)
+//		Created: 2003/08/28
+//
+// --------------------------------------------------------------------------
+NamedLock::~NamedLock()
+{
+	if(mFileDescriptor != -1)
+	{
+		ReleaseLock();
+	}
+}
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    NamedLock::TryAndGetLock(const char *, int)
+//		Purpose: Trys to get a lock on the name in the file system.
+//				 IMPORTANT NOTE: If a file exists with this name, it will be deleted.
+//		Created: 2003/08/28
+//
+// --------------------------------------------------------------------------
+bool NamedLock::TryAndGetLock(const char *Filename, int mode)
+{
+	// Check
+	if(mFileDescriptor != -1)
+	{
+		THROW_EXCEPTION(CommonException, NamedLockAlreadyLockingSomething)
+	}
+
+	// See if the lock can be got
+#ifdef PLATFORM_open_NO_O_EXLOCK
+	int fd = ::open(Filename, O_WRONLY | O_CREAT | O_TRUNC, mode);
+	if(fd == -1)
+	{
+		THROW_EXCEPTION(CommonException, OSFileError)
+	}
+	if(::flock(fd, LOCK_EX | LOCK_NB) != 0)
+	{
+		::close(fd);
+		if(errno == EWOULDBLOCK)
+		{
+			return false;
+		}
+		else
+		{
+			THROW_EXCEPTION(CommonException, OSFileError)
+		}
+	}
+
+	// Success
+	mFileDescriptor = fd;
+
+	return true;
+#else
+	int fd = ::open(Filename, O_WRONLY | O_NONBLOCK | O_CREAT | O_TRUNC | O_EXLOCK, mode);
+	if(fd != -1)
+	{
+		// Got a lock, lovely
+		mFileDescriptor = fd;
+		return true;
+	}
+	
+	// Failed. Why?
+	if(errno != EWOULDBLOCK)
+	{
+		// Not the expected error
+		THROW_EXCEPTION(CommonException, OSFileError)
+	}
+
+	return false;
+#endif
+}
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    NamedLock::ReleaseLock()
+//		Purpose: Release the lock. Exceptions if the lock is not held
+//		Created: 2003/08/28
+//
+// --------------------------------------------------------------------------
+void NamedLock::ReleaseLock()
+{
+	// Got a lock?
+	if(mFileDescriptor == -1)
+	{
+		THROW_EXCEPTION(CommonException, NamedLockNotHeld)
+	}
+	
+	// Close the file
+	if(::close(mFileDescriptor) != 0)
+	{
+		THROW_EXCEPTION(CommonException, OSFileError)
+	}
+	// Mark as unlocked
+	mFileDescriptor = -1;
+}
+
+
+
+