watcher: Add a method to query the watcher state

This allows a user to check if the watcher is actually running, and potentially
perform read operations directly instead of relying on watcher.

src/libstrongswan/processing/watcher.c

@@ -52,9 +52,9 @@ struct private_watcher_t {
 	bool pending;
 
 	/**
-	 * Is watcher running?
+	 * Running state of watcher
 	 */
-	bool running;
+	watcher_state_t state;
 
 	/**
 	 * Lock to access FD list
@@ -239,7 +239,7 @@ static void activate_all(private_watcher_t *this)
 		entry->in_callback = 0;
 	}
 	enumerator->destroy(enumerator);
-	this->running = FALSE;
+	this->state = WATCHER_STOPPED;
 	this->condvar->broadcast(this->condvar);
 	this->mutex->unlock(this->mutex);
 }
@@ -263,10 +263,14 @@ static job_requeue_t watch(private_watcher_t *this)
 
 	if (this->fds->get_count(this->fds) == 0)
 	{
-		this->running = FALSE;
+		this->state = WATCHER_STOPPED;
 		this->mutex->unlock(this->mutex);
 		return JOB_REQUEUE_NONE;
 	}
+	if (this->state == WATCHER_QUEUED)
+	{
+		this->state = WATCHER_RUNNING;
+	}
 
 	if (this->notify[0] != -1)
 	{
@@ -407,9 +411,9 @@ METHOD(watcher_t, add, void,
 
 	this->mutex->lock(this->mutex);
 	this->fds->insert_last(this->fds, entry);
-	if (!this->running)
+	if (this->state == WATCHER_STOPPED)
 	{
-		this->running = TRUE;
+		this->state = WATCHER_QUEUED;
 		lib->processor->queue_job(lib->processor,
 			(job_t*)callback_job_create_with_prio((void*)watch, this,
 				NULL, (callback_job_cancel_t)return_false, JOB_PRIO_CRITICAL));
@@ -437,7 +441,7 @@ METHOD(watcher_t, remove_, void,
 		{
 			if (entry->fd == fd)
 			{
-				if (this->running && entry->in_callback)
+				if (this->state != WATCHER_STOPPED && entry->in_callback)
 				{
 					is_in_callback = TRUE;
 					break;
@@ -458,6 +462,18 @@ METHOD(watcher_t, remove_, void,
 	this->mutex->unlock(this->mutex);
 }
 
+METHOD(watcher_t, get_state, watcher_state_t,
+	private_watcher_t *this)
+{
+	watcher_state_t state;
+
+	this->mutex->lock(this->mutex);
+	state = this->state;
+	this->mutex->unlock(this->mutex);
+
+	return state;
+}
+
 METHOD(watcher_t, destroy, void,
 	private_watcher_t *this)
 {
@@ -535,6 +551,7 @@ watcher_t *watcher_create()
 		.public = {
 			.add = _add,
 			.remove = _remove_,
+			.get_state = _get_state,
 			.destroy = _destroy,
 		},
 		.fds = linked_list_create(),
@@ -542,6 +559,7 @@ watcher_t *watcher_create()
 		.condvar = condvar_create(CONDVAR_TYPE_DEFAULT),
 		.jobs = linked_list_create(),
 		.notify = {-1, -1},
+		.state = WATCHER_STOPPED,
 	);
 
 	if (!create_notify(this))

src/libstrongswan/processing/watcher.h

@@ -23,6 +23,7 @@
 
 typedef struct watcher_t watcher_t;
 typedef enum watcher_event_t watcher_event_t;
+typedef enum watcher_state_t watcher_state_t;
 
 #include <library.h>
 
@@ -56,6 +57,18 @@ enum watcher_event_t {
 	WATCHER_EXCEPT = (1<<2),
 };
 
+/**
+ * State the watcher currently is in
+ */
+enum watcher_state_t {
+	/** no watcher thread running or queued */
+	WATCHER_STOPPED = 0,
+	/** a job has been queued for watching, but not yet started */
+	WATCHER_QUEUED,
+	/** a watcher thread is active, dispatching socket events */
+	WATCHER_RUNNING,
+};
+
 /**
  * Watch multiple file descriptors using select().
  */
@@ -85,6 +98,13 @@ struct watcher_t {
 	 */
 	void (*remove)(watcher_t *this, int fd);
 
+	/**
+	 * Get the current watcher state
+	 *
+	 * @reutrn			currently active watcher state
+	 */
+	watcher_state_t (*get_state)(watcher_t *this);
+
 	/**
 	 * Destroy a watcher_t.
 	 */