Defines the event system that wraps the Starboard main loop and entry point.
---------- *
| |
| Preload
| |
| V
Start [ PRELOADING ] ------------
| | |
| Start |
| | |
| V |
----> [ STARTED ] <---- |
| | |
Pause Unpause |
| | Suspend
V | |
-----> [ PAUSED ] ----- |
| | |
Resume Suspend |
| | |
| V |
---- [ SUSPENDED ] <------------
|
Stop
|
V
[ STOPPED ]
The first event that a Starboard application receives is either Start (kSbEventTypeStart) or Preload (kSbEventTypePreload). Start puts the application in the STARTED state, whereas Preload puts the application in the PRELOADING state.
PRELOADING can only happen as the first application state. In this state, the application should start and run as normal, but will not receive any input, and should not try to initialize graphics resources (via GL or SbBlitter). In PRELOADING, the application can receive Start or Suspend events. Start will receive the same data that was passed into Preload.
In the STARTED state, the application is in the foreground and can expect to do all of the normal things it might want to do. Once in the STARTED state, it may receive a Pause event, putting the application into the PAUSED state.
In the PAUSED state, the application is still visible, but has lost focus, or it is partially obscured by a modal dialog, or it is on its way to being shut down. The application should pause activity in this state. In this state, it can receive Unpause to be brought back to the foreground state (STARTED), or Suspend to be pushed further in the background to the SUSPENDED state.
In the SUSPENDED state, the application is generally not visible. It should immediately release all graphics and video resources, and shut down all background activity (timers, rendering, etc). Additionally, the application should flush storage to ensure that if the application is killed, the storage will be up-to-date. The application may be killed at this point, but will ideally receive a Stop event for a more graceful shutdown.
Note that the application is always expected to transition through PAUSED to SUSPENDED before receiving Stop or being killed.
An enumeration of all possible event types dispatched directly by the system. Each event is accompanied by a void* data argument, and each event must define the type of the value pointed to by that data argument, if any.
kSbEventTypeStart
The first event that an application receives on startup when starting normally (i.e. not being preloaded). Applications should perform initialization, start running, and prepare to react to subsequent events. Applications that wish to run and then exit must call SbSystemRequestStop() to terminate. This event will only be sent once for a given process launch. SbEventStartData is passed as the data argument. In case of preload, the SbEventStartData will be the same as what was passed to kSbEventTypePreload.
kSbEventTypePause
A dialog will be raised or the application will otherwise be put into a background-but-visible or partially-obscured state (PAUSED). Graphics and video resources will still be available, but the application should pause foreground activity like animations and video playback. Can only be received after a Start event. The only events that should be dispatched after a Pause event are Unpause or Suspend. No data argument.
kSbEventTypeUnpause
The application is returning to the foreground (STARTED) after having been put in the PAUSED (e.g. partially-obscured) state. The application should unpause foreground activity like animations and video playback. Can only be received after a Pause or Resume event. No data argument.
kSbEventTypeSuspend
The operating system will put the application into a Suspended state after this event is handled. The application is expected to stop periodic background work, release ALL graphics and video resources, and flush any pending SbStorage writes. Some platforms will terminate the application if work is done or resources are retained after suspension. Can only be received after a Pause event. The only events that should be dispatched after a Suspend event are Resume or Stop. On some platforms, the process may also be killed after Suspend without a Stop event. No data argument.
kSbEventTypeResume
The operating system has restored the application to the PAUSED state from the SUSPENDED state. This is the first event the application will receive coming out of SUSPENDED, and it will only be received after a Suspend event. The application will now be in the PAUSED state. No data argument.
kSbEventTypeStop
The operating system will shut the application down entirely after this event is handled. Can only be recieved after a Suspend event, in the SUSPENDED state. No data argument.
kSbEventTypeInput
A user input event, including keyboard, mouse, gesture, or something else. SbInputData (from input.h) is passed as the data argument.
kSbEventTypeUser
A user change event, which means a new user signed-in or signed-out, or the current user changed. No data argument, call SbUserGetSignedIn() and SbUserGetCurrent() to get the latest changes.
kSbEventTypeLink
A navigational link has come from the system, and the application should consider handling it by navigating to the corresponding application location. The data argument is an application-specific, null-terminated string.
kSbEventTypeVerticalSync
The beginning of a vertical sync has been detected. This event is very timing-sensitive, so as little work as possible should be done on the main thread if the application wants to receive this event in a timely manner. No data argument.
kSbEventTypeNetworkDisconnect
The platform has detected a network disconnection. The platform should make a best effort to send an event of this type when the network disconnects, but there are likely to be cases where the platform cannot detect the disconnection (e.g. if the connection is via a powered hub which becomes disconnected), so the current network state cannot always be inferred from the sequence of Connect/Disconnect events.
kSbEventTypeNetworkConnect
The platform has detected a network connection. This event may be sent at application start-up, and should always be sent if the network reconnects since a disconnection event was sent.
kSbEventTypeScheduled
An event type reserved for scheduled callbacks. It will only be sent in response to an application call to SbEventSchedule(), and it will call the callback directly, so SbEventHandle should never receive this event directly. The data type is an internally-defined structure.
kSbEventTypeAccessiblitySettingsChanged
The platform's accessibility settings have changed. The application should query the accessibility settings using the appropriate APIs to get the new settings.
kSbEventTypeOnScreenKeyboardShown
The platform has shown the on screen keyboard. This event is triggered by the system or by the OnScreenKeyboard's show method in javascript. The event has int data representing the ticket for looking up a promise reference stored by the on screen keyboard. Javascript-triggered events have tickets passed in via SbWindowShowOnScreenKeyboard. System-triggered events have ticket value kSbEventOnScreenKeyboardInvalidTicket.
kSbEventTypeOnScreenKeyboardHidden
The platform has hidden the on screen keyboard. This event is triggered by the system or by the OnScreenKeyboard's hide method in javascript. The event has int data representing the ticket for looking up a promise reference stored by the on screen keyboard. Javascript-triggered events have tickets passed in via SbWindowHideOnScreenKeyboard. System-triggered events have ticket value kSbEventOnScreenKeyboardInvalidTicket.
A function that can be called back from the main Starboard event pump.
typedef void(* SbEventCallback)(void *context)
A function that will cleanly destroy an event data instance of a specific type.
typedef void(* SbEventDataDestructor)(void *data)
An ID that can be used to refer to a scheduled event.
typedef uint32_t SbEventId
Structure representing a Starboard event and its data.
SbEventType typevoid * dataEvent data for kSbEventTypeStart events.
char ** argument_values
The command-line argument values (argv).
int argument_count
The command-line argument count (argc).
const char * link
The startup link, if any.
Cancels the specified event_id. Note that this function is a no-op if the event already fired. This function can be safely called from any thread, but the only way to guarantee that the event does not run anyway is to call it from the main Starboard event loop thread.
void SbEventCancel(SbEventId event_id)
The entry point that Starboard applications MUST implement. Any memory pointed at by event or the data field inside event is owned by the system, and that memory is reclaimed after this function returns, so the implementation must copy this data to extend its life. This behavior should also be assumed of all fields within the data object, unless otherwise explicitly specified.
This function is only called from the main Starboard thread. There is no specification about what other work might happen on this thread, so the application should generally do as little work as possible on this thread, and just dispatch it over to another thread.
SB_IMPORT void SbEventHandle(const SbEvent *event)
Returns whether the given event handle is valid.
static bool SbEventIsIdValid(SbEventId handle)
Schedules an event callback into the main Starboard event loop. This function may be called from any thread, but callback is always called from the main Starboard thread, queued with other pending events.
callback: The callback function to be called. context: The context that is passed to the callback function. delay: The minimum number of microseconds to wait before calling the callback function. Set delay to 0 to call the callback as soon as possible.
SbEventId SbEventSchedule(SbEventCallback callback, void *context, SbTime delay)