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-rw-r--r--include/threadengine.h71
1 files changed, 63 insertions, 8 deletions
diff --git a/include/threadengine.h b/include/threadengine.h
index 9c87f83b2..d41ad98d3 100644
--- a/include/threadengine.h
+++ b/include/threadengine.h
@@ -29,7 +29,9 @@ class Thread;
* This allows Thread classes to be derived without needing to know how
* the OS implements threads. You should ensure that any sections of code
* that use threads are threadsafe and do not interact with any other
- * parts of the code which are NOT known threadsafe!
+ * parts of the code which are NOT known threadsafe! If you really MUST
+ * access non-threadsafe code from a Thread, use the Mutex class to wrap
+ * access to the code carefully.
*/
class CoreExport ThreadEngine : public Extensible
{
@@ -44,7 +46,8 @@ class CoreExport ThreadEngine : public Extensible
public:
- /** Constructor
+ /** Constructor.
+ * @param Instance Creator object
*/
ThreadEngine(InspIRCd* Instance);
@@ -53,53 +56,98 @@ class CoreExport ThreadEngine : public Extensible
virtual ~ThreadEngine();
/** Enable or disable system-wide mutex for threading.
- * This MUST be called when you deal with ANYTHING that
- * isnt known thread-safe, this INCLUDES STL!
* Remember that if you toggle the mutex you MUST UNSET
* IT LATER otherwise the program will DEADLOCK!
+ * It is recommended that you AVOID USE OF THIS METHOD
+ * and use your own Mutex class, this function is mainly
+ * reserved for use by the core and by the Thread engine
+ * itself.
+ * @param enable True to lock the mutex.
*/
virtual bool Mutex(bool enable) = 0;
- /** Run the newly created thread
+ /** Run the newly created thread.
*/
virtual void Run() = 0;
/** Create a new thread. This takes an already allocated
* Thread* pointer and initializes it to use this threading
* engine. On failure, this function may throw a CoreException.
+ * @param thread_to_init Pointer to a newly allocated Thread
+ * derived object.
*/
virtual void Create(Thread* thread_to_init) = 0;
/** This is called by the default destructor of the Thread
* class to ensure that the thread engine which created the thread
* is responsible for destroying it.
+ * @param thread Existing and active thread to delete.
*/
virtual void FreeThread(Thread* thread) = 0;
+ /** Returns the thread engine's name for display purposes
+ * @return The thread engine name
+ */
virtual const std::string GetName()
{
return "<pure-virtual>";
}
};
+/** The Mutex class represents a mutex, which can be used to keep threads
+ * properly synchronised. Use mutexes sparingly, as they are a good source
+ * of thread deadlocks etc, and should be avoided except where absolutely
+ * neccessary. Note that the internal behaviour of the mutex varies from OS
+ * to OS depending on the thread engine, for example in windows a Mutex
+ * in InspIRCd uses critical sections, as they are faster and simpler to
+ * manage.
+ */
class CoreExport Mutex : public Extensible
{
protected:
+
+ /** Creator object
+ */
InspIRCd* ServerInstance;
+
+ /** Enable or disable the Mutex. This method has somewhat confusing
+ * wording (e.g. the function name and parameters) so it is protected
+ * in preference of the Lock() and Unlock() methods which are user-
+ * accessible.
+ *
+ * @param enable True to enable the mutex (enter it) and false to
+ * disable the mutex (leave it).
+ */
+ virtual void Enable(bool enable) = 0;
public:
+
+ /** Constructor.
+ * @param Instance Creator object
+ */
Mutex(InspIRCd* Instance);
- virtual void Enable(bool enable) = 0;
+
+ /** Enter/enable the mutex lock.
+ */
void Lock() { Enable(true); }
+
+ /** Leave/disable the mutex lock.
+ */
void Unlock() { Enable(false); }
+
+ /** Destructor
+ */
~Mutex() { }
};
/** Derive from this class to implement your own threaded sections of
- * code.
+ * code. Be sure to keep your code thread-safe and not prone to deadlocks
+ * and race conditions if you MUST use threading!
*/
class CoreExport Thread : public Extensible
{
private:
+ /** Set to true when the thread is to exit
+ */
bool ExitFlag;
public:
@@ -123,20 +171,27 @@ class CoreExport Thread : public Extensible
}
/** Override this method to put your actual
- * threaded code here
+ * threaded code here.
*/
virtual void Run() = 0;
+ /** Signal the thread to exit gracefully.
+ */
void SetExitFlag()
{
ExitFlag = true;
}
+ /** Cancel an exit state.
+ */
void ClearExitFlag()
{
ExitFlag = false;
}
+ /** Get thread's current exit status.
+ * (are we being asked to exit?)
+ */
bool GetExitFlag()
{
return ExitFlag;