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// Copyright 2015 The Cobalt Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Module Overview: Starboard Event module
//
// Defines the event system that wraps the Starboard main loop and entry point.
//
// # The Starboard Application Lifecycle
//
// * ----------
// | |
// Start |
// | |
// V |
// [===========] |
// ---> [ STARTED ] |
// | [===========] |
// | | |
// Focus Blur Preload
// | | |
// | V |
// ---- [===========] |
// ---> [ BLURRED ] |
// | [===========] |
// | | |
// Reveal Conceal |
// | | |
// | V |
// | [===========] |
// ---- [ CONCEALED ] <---
// ---> [===========]
// | |
// Unfreeze Freeze
// | |
// | V
// | [===========]
// ---- [ FROZEN ]
// [===========]
// |
// 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 |CONCEALED| state.
//
// 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 |Blur| event, putting the application into the
// |BLURRED| state.
//
// In the |BLURRED| 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 blur activity in this state.
// In this state, it can receive |Focus| to be brought back to the foreground
// state (|STARTED|), or |Conceal| to be pushed to the |CONCEALED| state.
//
// In the |CONCEALED| state, the application should behave as it should for
// an invisible program that can still run, and that can optionally access
// the network and playback audio, albeit potentially will have less
// CPU and memory available. The application may get switched from |CONCEALED|
// to |FROZEN| at any time, when the platform decides to do so.
//
// In the |FROZEN| state, the application is 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 |BLURRED|,
// |CONCEALED| to |FROZEN| before receiving |Stop| or being killed.
#ifndef STARBOARD_EVENT_H_
#define STARBOARD_EVENT_H_
#include "starboard/configuration.h"
#include "starboard/export.h"
#include "starboard/time.h"
#include "starboard/types.h"
#include "starboard/window.h"
#ifdef __cplusplus
extern "C" {
#endif
// 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.
typedef enum SbEventType {
// Applications should perform initialization and prepare to react to
// subsequent events, but must not initialize any graphics resources through
// GL. The intent of this event is to allow the application to
// do as much work as possible ahead of time, so that when the application is
// first brought to the foreground, it's as fast as a resume.
// The system may send |kSbEventTypePreload| in |UNSTARTED| if it wants to
// push the app into a lower resource consumption state. Applications will
// also call SbSystemRequestConceal() when they request this. The only
// events that should be dispatched after a Preload event are Reveal or
// Freeze. No data argument.
kSbEventTypePreload,
// The first event that an application receives on startup when starting
// normally. 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.
kSbEventTypeStart,
// A dialog will be raised or the application will otherwise be put into a
// background-but-visible or partially-obscured state (BLURRED). Graphics and
// video resources will still be available, but the application could 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 Blur event are Focus or Conceal. No data argument.
kSbEventTypeBlur,
// The application is returning to the foreground (STARTED) after having been
// put in the BLURRED (e.g. partially-obscured) state. The application should
// resume foreground activity like animations and video playback. Can only be
// received after a Blur or Reveal event. No data argument.
kSbEventTypeFocus,
// The operating system will put the application into the Concealed state
// after this event is handled. The application is expected to be made
// invisible, but background tasks can still be running, such as audio
// playback, or updating of recommendations. Can only be received after a
// Blur or Reveal event. The only events that should be dispatched after
// a Conceal event are Freeze or Reveal. On some platforms, the process may
// also be killed after Conceal without a Freeze event.
kSbEventTypeConceal,
// The operating system will restore the application to the BLURRED state
// from the CONCEALED state. This is the first event the application will
// receive coming out of CONCEALED, and it can be received after a
// Conceal or Unfreeze event. The application will now be in the BLURRED
// state. No data argument.
kSbEventTypeReveal,
// The operating system will put the application into the Frozen 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 freezing. Can be received
// after a Conceal or Unfreeze event. The only events that should be
// dispatched after a Freeze event are Unfreeze or Stop. On some platforms,
// the process may also be killed after Freeze without a Stop event.
// No data argument.
kSbEventTypeFreeze,
// The operating system has restored the application to the CONCEALED state
// from the FROZEN state. This is the first event the application will receive
// coming out of FROZEN, and it will only be received after a Freeze event.
// The application will now be in the CONCEALED state. NO data argument.
kSbEventTypeUnfreeze,
// The operating system will shut the application down entirely after this
// event is handled. Can only be received after a Freeze event, in the
// FROZEN state. No data argument.
kSbEventTypeStop,
// A user input event, including keyboard, mouse, gesture, or something else.
// SbInputData (from input.h) is passed as the data argument.
kSbEventTypeInput,
// A user change event, which means a new user signed-in or signed-out, or the
// current user changed. No data argument.
kSbEventTypeUser,
// 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.
kSbEventTypeLink,
// 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.
kSbEventTypeVerticalSync,
// 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.
kSbEventTypeScheduled,
// The platform's accessibility settings have changed. The application should
// query the accessibility settings using the appropriate APIs to get the
// new settings. Note this excludes captions settings changes, which
// causes kSbEventTypeAccessibilityCaptionSettingsChanged to fire. If the
// starboard version has
// kSbEventTypeAccessib(i)lityTextToSpeechSettingsChanged, then that event
// should be used to signal text-to-speech settings changes instead; platforms
// using older starboard versions should use
// kSbEventTypeAccessib(i)litySettingsChanged for text-to-speech settings
// changes.
kSbEventTypeAccessibilitySettingsChanged,
// An optional event that platforms may send to indicate that the application
// may soon be terminated (or crash) due to low memory availability. The
// application may respond by reducing memory consumption by running a Garbage
// Collection, flushing caches, or something similar. There is no requirement
// to respond to or handle this event, it is only advisory.
kSbEventTypeLowMemory,
// The size or position of a SbWindow has changed. The data is
// SbEventWindowSizeChangedData.
kSbEventTypeWindowSizeChanged,
// The platform has shown the on screen keyboard. This event is triggered by
// the system or by the application's OnScreenKeyboard show method. The event
// has int data representing a ticket. The ticket is used by the application
// to mark individual calls to the show method as successfully completed.
// Events triggered by the application have tickets passed in via
// SbWindowShowOnScreenKeyboard. System-triggered events have ticket value
// kSbEventOnScreenKeyboardInvalidTicket.
kSbEventTypeOnScreenKeyboardShown,
// The platform has hidden the on screen keyboard. This event is triggered by
// the system or by the application's OnScreenKeyboard hide method. The event
// has int data representing a ticket. The ticket is used by the application
// to mark individual calls to the hide method as successfully completed.
// Events triggered by the application have tickets passed in via
// SbWindowHideOnScreenKeyboard. System-triggered events have ticket value
// kSbEventOnScreenKeyboardInvalidTicket.
kSbEventTypeOnScreenKeyboardHidden,
// The platform has focused the on screen keyboard. This event is triggered by
// the system or by the application's OnScreenKeyboard focus method. The event
// has int data representing a ticket. The ticket is used by the application
// to mark individual calls to the focus method as successfully completed.
// Events triggered by the application have tickets passed in via
// SbWindowFocusOnScreenKeyboard. System-triggered events have ticket value
// kSbEventOnScreenKeyboardInvalidTicket.
kSbEventTypeOnScreenKeyboardFocused,
// The platform has blurred the on screen keyboard. This event is triggered by
// the system or by the application's OnScreenKeyboard blur method. The event
// has int data representing a ticket. The ticket is used by the application
// to mark individual calls to the blur method as successfully completed.
// Events triggered by the application have tickets passed in via
// SbWindowBlurOnScreenKeyboard. System-triggered events have ticket value
// kSbEventOnScreenKeyboardInvalidTicket.
kSbEventTypeOnScreenKeyboardBlurred,
// The platform has updated the on screen keyboard suggestions. This event is
// triggered by the system or by the application's OnScreenKeyboard update
// suggestions method. The event has int data representing a ticket. The
// ticket is used by the application to mark individual calls to the update
// suggestions method as successfully completed. Events triggered by the
// application have tickets passed in via
// SbWindowUpdateOnScreenKeyboardSuggestions. System-triggered events have
// ticket value kSbEventOnScreenKeyboardInvalidTicket.
kSbEventTypeOnScreenKeyboardSuggestionsUpdated,
// One or more of the fields returned by SbAccessibilityGetCaptionSettings
// has changed.
kSbEventTypeAccessibilityCaptionSettingsChanged,
// The platform's text-to-speech settings have changed.
kSbEventTypeAccessibilityTextToSpeechSettingsChanged,
// The platform has detected a network disconnection. There are likely to
// be cases where the platform cannot detect the disconnection but the
// platform should make a best effort to send an event of this type when
// the network disconnects. This event is used to implement
// window.onoffline DOM event.
kSbEventTypeOsNetworkDisconnected,
// The platform has detected a network connection. There are likely to
// be cases where the platform cannot detect the connection but the
// platform should make a best effort to send an event of this type when
// the device is just connected to the internet. This event is used
// to implement window.ononline DOM event.
kSbEventTypeOsNetworkConnected,
// The platform has detected a date and/or time configuration change (such
// as a change in the timezone setting). This should trigger the application
// to re-query the relevant APIs to update the date and time.
kSbEventDateTimeConfigurationChanged,
} SbEventType;
// Structure representing a Starboard event and its data.
typedef struct SbEvent {
SbEventType type;
SbTimeMonotonic timestamp;
void* data;
} SbEvent;
// 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;
// Event data for kSbEventTypeStart events.
typedef struct SbEventStartData {
// The command-line argument values (argv).
char** argument_values;
// The command-line argument count (argc).
int argument_count;
// The startup link, if any.
const char* link;
} SbEventStartData;
// Event data for kSbEventTypeWindowSizeChanged events.
typedef struct SbEventWindowSizeChangedData {
SbWindow window;
SbWindowSize size;
} SbEventWindowSizeChangedData;
#define kSbEventIdInvalid (SbEventId)0
// Returns whether the given event handle is valid.
static SB_C_FORCE_INLINE bool SbEventIsIdValid(SbEventId handle) {
return handle != kSbEventIdInvalid;
}
#if SB_API_VERSION >= 15
typedef void (*SbEventHandleCallback)(const SbEvent* event);
// Serves as the entry point in the Starboard library for running the Starboard
// event loop with the application event handler.
SB_EXPORT int SbRunStarboardMain(int argc,
char** argv,
SbEventHandleCallback callback);
#endif // SB_API_VERSION >= 15
// 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.
#if SB_API_VERSION >= 15
SB_EXPORT_PLATFORM void SbEventHandle(const SbEvent* event);
#else
SB_IMPORT void SbEventHandle(const SbEvent* event);
#endif // SB_API_VERSION >= 15
// 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. Must not be NULL.
// |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.
SB_EXPORT SbEventId SbEventSchedule(SbEventCallback callback,
void* context,
SbTime delay);
// 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.
SB_EXPORT void SbEventCancel(SbEventId event_id);
#ifdef __cplusplus
} // extern "C"
#endif
#endif // STARBOARD_EVENT_H_