Added AIFetchInventoryFolder and more.

Added a new statemachine AIFetchInventoryFolder, which can be used
to fetch the contents of a folder by name or UUID.

Also added AIEvent (and one event,
AIEvent::LLInventoryModel_mIsAgentInvUsable_true, which is needed
for AIFetchInventoryFolder).

Fixed LLInventoryModel::sBackgroundFetchActive to correctly reflect
whether or not LLInventoryModel::backgroundFetch is added to
gIdleCallbacks.

Avoid duplicated entries in sFetchQueue.

Reset sFullFetchStarted in LLInventoryModel::stopBackgroundFetch to
allow for a renewed full fetch when some single-folder fetch stops it.

Added AIStateMachine::mQueued to make calling 'cont()' more robust:
calling cont() / idle() / cont() on a row would otherwise add a
statemachine twice to the active list, which would cause a crash
when it's killed.

indra/newview/statemachine/aievent.h

@@ -0,0 +1,78 @@
+/**
+ * @file aievent.h
+ * @brief Collect viewer events for statemachines.
+ *
+ * Copyright (c) 2011, Aleric Inglewood.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * There are special exceptions to the terms and conditions of the GPL as
+ * it is applied to this Source Code. View the full text of the exception
+ * in the file doc/FLOSS-exception.txt in this software distribution.
+ *
+ * CHANGELOG
+ *   and additional copyright holders.
+ *
+ *   19/05/2011
+ *   Initial version, written by Aleric Inglewood @ SL
+ */
+
+#ifndef AIEVENT_H
+#define AIEVENT_H
+
+class AIStateMachine;
+
+class AIEvent {
+  public:
+	enum AIEvents {
+		LLInventoryModel_mIsAgentInvUsable_true,		// LLInventoryModel::mIsAgentInvUsable was set to true.
+		number_of_events
+	};
+
+	/**
+	 * Register a statemachine for the given event.
+	 *
+	 * If the event happens then statemachine->cont() is called.
+	 * 
+	 * @param event the event that we want to be notified of.
+	 * @param statemachine the statemachine.
+	 * @param one_shot if true then AIEvent::Unregister is called automatically when the event occured once.
+	 */
+	static void Register(AIEvents event, AIStateMachine* statemachine, bool one_shot = true);
+
+	/**
+	 * Unregister a previously registered event.
+	 *
+	 * This may be called for already unregistered events.
+	 * This should be called from the destructor of a statemachine for any event it registers,
+	 * as well as when it doesn't need the event anymore (in the case on non- one shot events).
+	 *
+	 * @param event the event we want to no longer be notified off.
+	 * @param statemachine the statemachine.
+	 */
+	static void Unregister(AIEvents event, AIStateMachine* statemachine);
+
+	/**
+	 * Trigger the event.
+	 *
+	 * This is called by the viewer code when the event happens and
+	 * causes statemachine->cont() to be called for every registered
+	 * statemachine.
+	 *
+	 * @param event the event that just happened.
+	 */
+	static void trigger(AIEvents event);
+};
+
+#endif