OpenHarmony源码解析之基于wayland的输入系统 原创 精华
作者：孙仲毅
简介
在之前一篇文章《OpenHarmony 多模输入子系统源码分析之事件派发流程 & 接口说明》中分析的输入系统的逻辑的是基于openharmony L0系统的，而本篇文章是基于openharmony L2系统的，在L2系统中输入系统并不是由InputManagerService, InputEventHub, InputEventDistributer来负责处理的输入事件的，而是由第三方库wayland来负责处理输入事件的，所以本章内容就是分析基于wayland协议的输入系统。
输入系统框架
整个输入流程的派发过程：
kernel ->HDF->uinput -> libinput –> weston -> wayland client -> wm -> ACE -> JS应用
当底层有事件发生的时候会通过驱动给HDF, 然后通过HDI接口给uinput，然后uinput会通过注入事件的方式把事件注入到libinput中，当libinput检测到有事件传上来的时候就会进行处理，处理完会给weston继续处理和派发，weston处理完后会通过wayland协议传给wayland client端，这是一个IPC调用，wayland处理完后会继续派发给windowmanager(简称wm)，之后通过ACE传给JS应用。
输入系统事件派发流程
首先在device_info.hcs和input_config.hcs配置文件中配置相应的信息，多模输入系统的HdfDeviceEventManager会在启动的时候去bind对应的hdf service, 然后通过RegisterReportCallback去注册对应的回调函数。
foundation\multimodalinput\input\uinput\hdf_device_event_manager.cpp
void HdfDeviceEventManager::ConnectHDFInit()
{
uint32_t ret = GetInputInterface(&inputInterface_);
if (ret != 0) {
HiLog::Error(LABEL, "Initialize %{public}s fail! ret is %{public}u", __func__, ret);
return;
}
if (inputInterface_ == nullptr || inputInterface_->iInputManager == nullptr) {
HiLog::Error(LABEL, "%{public}s inputInterface_ or iInputManager is NULL", __func__);
return;
}
thread_ = std::thread(&InjectThread::InjectFunc, injectThread_);
ret = inputInterface_->iInputManager->OpenInputDevice(TOUCH_DEV_ID);
if ((ret == INPUT_SUCCESS) && (inputInterface_->iInputReporter != nullptr)) {
ret = inputInterface_->iInputManager->GetInputDevice(TOUCH_DEV_ID, &iDevInfo_);
if (ret != INPUT_SUCCESS) {
HiLog::Error(LABEL, "%{public}s GetInputDevice error %{public}d", __func__, ret);
return;
}
std::unique_ptr<HdfDeviceEventDispatch> hdf = std::make_unique<HdfDeviceEventDispatch>(\
iDevInfo_->attrSet.axisInfo[ABS_MT_POSITION_X].max, iDevInfo_->attrSet.axisInfo[ABS_MT_POSITION_Y].max);
if (hdf == nullptr) {
HiLog::Error(LABEL, "%{public}s hdf is nullptr", __func__);
return;
}
callback_.EventPkgCallback = hdf->GetEventCallbackDispatch;
ret = inputInterface_->iInputReporter->RegisterReportCallback(TOUCH_DEV_ID, &callback_);
}
}
当有事件上来的时候就会回调GetEventCallbackDispatch
foundation\multimodalinput\input\uinput\hdf_device_event_dispatch.cpp
void HdfDeviceEventDispatch::GetEventCallbackDispatch(
const EventPackage **pkgs, uint32_t count, uint32_t devIndex)
{
if (pkgs == nullptr) {
HiLog::Error(LABEL, " %{public}s fail! pkgs is nullptr", __func__);
return;
}
for (uint32_t i = 0; i < count; i++) {
if (pkgs[i] == nullptr) {
continue;
}
if ((pkgs[i]->type == 0) && (pkgs[i]->code == 0) && (pkgs[i]->value == 0)) {
InjectInputEvent injectInputSync = {injectThread_.TOUCH_SCREEN_DEVICE_ID, 0, SYN_MT_REPORT, 0};
injectThread_.WaitFunc(injectInputSync);
}
InjectInputEvent injectInputEvent = {
injectThread_.TOUCH_SCREEN_DEVICE_ID,
pkgs[i]->type,
pkgs[i]->code,
pkgs[i]->value
};
injectThread_.WaitFunc(injectInputEvent);
}
}
然后通过InjectThread::WaitFunc准备对事件进行注入，在该函数中会通过notify_one来唤醒InjectFunc这个函数
foundation\multimodalinput\input\uinput\inject_thread.cpp
void InjectThread::InjectFunc() const
{
std::unique_lock<std::mutex> uniqueLock(mutex_);
while (true) {
conditionVariable_.wait(uniqueLock);
while (injectQueue_.size() > 0) {
if (injectQueue_[0].deviceId == TOUCH_SCREEN_DEVICE_ID) {
g_pTouchScreen->EmitEvent(injectQueue_[0].type, injectQueue_[0].code, injectQueue_[0].value);
} else if (injectQueue_[0].deviceId == KEYBOARD_DEVICE_ID) {
g_pKeyboard->EmitEvent(injectQueue_[0].type, injectQueue_[0].code, injectQueue_[0].value);
}
injectQueue_.erase(injectQueue_.begin());
}
}
}
void InjectThread::WaitFunc(InjectInputEvent injectInputEvent) const
{
std::lock_guard<std::mutex> lockGuard(mutex_);
injectQueue_.push_back(injectInputEvent);
conditionVariable_.notify_one();
}
最终会调用VirtualDevice::EmitEvent, 在该函数中会将事件写入到uinput的设备文件中。
foundation\multimodalinput\input\uinput\virtual_device.cpp
fd_ = open("/dev/uinput", O_WRONLY | O_NONBLOCK);
bool VirtualDevice::EmitEvent(uint16_t type, uint16_t code, uint32_t value) const
{
struct input_event event {};
event.type = type;
event.code = code;
event.value = value;
#ifndef __MUSL__
gettimeofday(&event.time, NULL);
#endif
if (write(fd_, &event, sizeof(event)) < static_cast<ssize_t>(sizeof(event))) {
HiLog::Error(LABEL, "Event write failed %{public}s aborting", __func__);
return false;
}
return true;
}
当uinput有上报输入事件的时候，fd就会发生变化从而就会调用回调函数libinput_source_dispatch，再继续调用udev_input_dispatch，在udev_input_dispatch中再继续调用process_events。
third_party\weston\libweston\libinput-seat.c
static int
udev_input_dispatch(struct udev_input *input)
{
if (libinput_dispatch(input->libinput) != 0)
weston_log("libinput: Failed to dispatch libinput\n");
process_events(input);
return 0;
}
static int
libinput_source_dispatch(int fd, uint32_t mask, void *data)
{
struct udev_input *input = data;
return udev_input_dispatch(input) != 0;
}
在process_events中会遍历每个event，然后调用process_event来处理每个event。
third_party\weston\libweston\libinput-seat.c
static void
process_events(struct udev_input *input)
{
struct libinput_event *event;
while ((event = libinput_get_event(input->libinput))) {
process_event(event);
// for multi model input.
if (g_libinput_event_listener)
{
weston_log("process_events: call libinput_event_listener.\n");
g_libinput_event_listener(event);
}
else
{
weston_log("process_events: libinput_event_listener is not set.\n");
}
libinput_event_destroy(event);
}
}
在process_event中，udev_input_process_event这个函数是处理设备的添加和删除，evdev_device_process_event_l这个函数是处理输入事件的。
third_party\weston\libweston\libinput-seat.c
static void
process_event(struct libinput_event *event)
{
if (udev_input_process_event(event))
return;
if (evdev_device_process_event_l(event))
return;
}
在这个函数中会根据不同的事件类型调用不同事件类型的处理函数
third_party\weston\libweston\libinput-device.c
int
evdev_device_process_event_l(struct libinput_event *event)
{
struct libinput_device *libinput_device =
libinput_event_get_device(event);
struct evdev_device *device =
libinput_device_get_user_data(libinput_device);
int handled = 1;
bool need_frame = false;
switch (libinput_event_get_type(event)) {
case LIBINPUT_EVENT_KEYBOARD_KEY:
handle_keyboard_key(libinput_device,
libinput_event_get_keyboard_event(event));
break;
case LIBINPUT_EVENT_POINTER_MOTION:
need_frame = handle_pointer_motion(libinput_device,
libinput_event_get_pointer_event(event));
break;
case LIBINPUT_EVENT_POINTER_MOTION_ABSOLUTE:
need_frame = handle_pointer_motion_absolute(
libinput_device,
libinput_event_get_pointer_event(event));
break;
case LIBINPUT_EVENT_POINTER_BUTTON:
need_frame = handle_pointer_button(libinput_device,
libinput_event_get_pointer_event(event));
break;
case LIBINPUT_EVENT_POINTER_AXIS:
need_frame = handle_pointer_axis(
libinput_device,
libinput_event_get_pointer_event(event));
break;
case LIBINPUT_EVENT_TOUCH_DOWN:
handle_touch_down(libinput_device,
libinput_event_get_touch_event(event));
break;
case LIBINPUT_EVENT_TOUCH_MOTION:
handle_touch_motion(libinput_device,
libinput_event_get_touch_event(event));
break;
case LIBINPUT_EVENT_TOUCH_UP:
handle_touch_up(libinput_device,
libinput_event_get_touch_event(event));
break;
case LIBINPUT_EVENT_TOUCH_FRAME:
handle_touch_frame(libinput_device,
libinput_event_get_touch_event(event));
break;
default:
handled = 0;
weston_log("unknown libinput event %d\n",
libinput_event_get_type(event));
}
if (need_frame)
notify_pointer_frame(device->seat);
return handled;
}
先以key事件为例，看handle_keyboard_key这个函数，在这个函数中会获取按键的状态（按下和抬起），然后通过notify_key来派发事件。
third_party\weston\libweston\libinput-device.c
static void
handle_keyboard_key(struct libinput_device *libinput_device,
struct libinput_event_keyboard *keyboard_event)
{
struct evdev_device *device =
libinput_device_get_user_data(libinput_device);
int key_state =
libinput_event_keyboard_get_key_state(keyboard_event);
int seat_key_count =
libinput_event_keyboard_get_seat_key_count(keyboard_event);
struct timespec time;
/* Ignore key events that are not seat wide state changes. */
if ((key_state == LIBINPUT_KEY_STATE_PRESSED &&
seat_key_count != 1) ||
(key_state == LIBINPUT_KEY_STATE_RELEASED &&
seat_key_count != 0))
return;
timespec_from_usec(&time,
libinput_event_keyboard_get_time_usec(keyboard_event));
notify_key(device->seat, &time,
libinput_event_keyboard_get_key(keyboard_event),
key_state, STATE_UPDATE_AUTOMATIC);
}
在notiyf_key这个函数中，会执行grab->interface->key，grab是指向weston_keyboard_grab这个结构体的函数指针，grab->interface->key其实就是调用default_grab_keyboard_key。
third_party\weston\libweston\input.c
WL_EXPORT void
notify_key(struct weston_seat *seat, const struct timespec *time, uint32_t key,
enum wl_keyboard_key_state state,
enum weston_key_state_update update_state)
{
struct weston_compositor *compositor = seat->compositor;
struct weston_keyboard *keyboard = weston_seat_get_keyboard(seat);
struct weston_keyboard_grab *grab = keyboard->grab;
uint32_t *k, *end;
if (state == WL_KEYBOARD_KEY_STATE_PRESSED) {
weston_compositor_idle_inhibit(compositor);
} else {
weston_compositor_idle_release(compositor);
}
end = keyboard->keys.data + keyboard->keys.size;
for (k = keyboard->keys.data; k < end; k++) {
if (*k == key) {
/* Ignore server-generated repeats. */
if (state == WL_KEYBOARD_KEY_STATE_PRESSED)
return;
*k = *--end;
}
}
keyboard->keys.size = (void *) end - keyboard->keys.data;
if (state == WL_KEYBOARD_KEY_STATE_PRESSED) {
k = wl_array_add(&keyboard->keys, sizeof *k);
*k = key;
}
if (grab == &keyboard->default_grab ||
grab == &keyboard->input_method_grab) {
weston_compositor_run_key_binding(compositor, keyboard, time,
key, state);
grab = keyboard->grab;
}
grab->interface->key(grab, time, key, state);
if (keyboard->pending_keymap &&
keyboard->keys.size == 0)
update_keymap(seat);
if (update_state == STATE_UPDATE_AUTOMATIC) {
update_modifier_state(seat,
wl_display_get_serial(compositor->wl_display),
key,
state);
}
keyboard->grab_serial = wl_display_get_serial(compositor->wl_display);
if (state == WL_KEYBOARD_KEY_STATE_PRESSED) {
keyboard->grab_time = *time;
keyboard->grab_key = key;
}
}
在default_grab_keyboard_key中会继续调用weston_keyboard_send_key。在wayland协议中，在Server和Client之间，对象是一一对应的，互相知道这个对象的状态。Client是 wl_proxy，与之对应的，在Server就会有一个 wl_resource。之后会遍历所有的wl_resource，然后调用各自的wl_keyboard_send_key。
third_party\weston\libweston\input.c
static void
default_grab_keyboard_key(struct weston_keyboard_grab *grab,
const struct timespec *time, uint32_t key,
uint32_t state)
{
weston_keyboard_send_key(grab->keyboard, time, key, state);
}
WL_EXPORT void
weston_keyboard_send_key(struct weston_keyboard *keyboard,
const struct timespec *time, uint32_t key,
enum wl_keyboard_key_state state)
{
struct wl_resource *resource;
struct wl_display *display = keyboard->seat->compositor->wl_display;
uint32_t serial;
struct wl_list *resource_list;
uint32_t msecs;
if (!weston_keyboard_has_focus_resource(keyboard))
return;
resource_list = &keyboard->focus_resource_list;
serial = wl_display_next_serial(display);
msecs = timespec_to_msec(time);
wl_resource_for_each(resource, resource_list) {
send_timestamps_for_input_resource(resource,
&keyboard->timestamps_list,
time);
wl_keyboard_send_key(resource, serial, msecs, key, state);
}
};
wl_keyboard_send_key其实会进行IPC调用，通过wayland协议，把server端的信息传给client端。Wayland核心协议是通过protocol/wayland.xml这个文件定义的。它通过wayland_scanner这个程序扫描后会生成wayland-protocol.c, wayland-client-protocol.h和wayland-server-protocol.h三个文件。wayland-client-protocol.h是给Client用的；wayland-server-protocol.h是给Server用的; wayland-protocol.c描述了接口，Client和Server都会用。根据wayland协议，这个函数会调用到服务端wayland-server的wl_resouce_post_event。
out\ohos-arm-release\gen\third_party\wayland_standard\protocol\wayland-server-protocol.h
static inline void
wl_keyboard_send_key(struct wl_resource *resource_, uint32_t serial, uint32_t time, uint32_t key, uint32_t state)
{
wl_resource_post_event(resource_, WL_KEYBOARD_KEY, serial, time, key, state);
}
在wl_resource_post_event中会继续调用wl_resource_post_event_array，在调用handle_array的时候会传入函数指针wl_closure_send。
third_party\wayland_standard\src\wayland-server.c
WL_EXPORT void
wl_resource_post_event_array(struct wl_resource *resource, uint32_t opcode,
union wl_argument *args)
{
handle_array(resource, opcode, args, wl_closure_send);
}
WL_EXPORT void
wl_resource_post_event(struct wl_resource *resource, uint32_t opcode, ...)
{
union wl_argument args[WL_CLOSURE_MAX_ARGS];
struct wl_object *object = &resource->object;
va_list ap;
va_start(ap, opcode);
wl_argument_from_va_list(object->interface->events[opcode].signature,
args, WL_CLOSURE_MAX_ARGS, ap);
va_end(ap);
wl_resource_post_event_array(resource, opcode, args);
}
在handle_array中，会调用send_func这个函数指针说指向的函数，实际上就是调用wl_closure_send这个函数。
third_party\wayland_standard\src\wayland-server.c
static void
handle_array(struct wl_resource *resource, uint32_t opcode,
union wl_argument *args,
int (*send_func)(struct wl_closure *, struct wl_connection *))
{
struct wl_closure *closure;
struct wl_object *object = &resource->object;
if (resource->client->error)
return;
if (!verify_objects(resource, opcode, args)) {
resource->client->error = 1;
return;
}
closure = wl_closure_marshal(object, opcode, args,
&object->interface->events[opcode]);
if (closure == NULL) {
resource->client->error = 1;
return;
}
log_closure(resource, closure, true);
if (send_func(closure, resource->client->connection))
resource->client->error = 1;
wl_closure_destroy(closure);
}
wl_connection代表Server与Client的连接，其中包含了in buffer和out buffer，分别作为输入和输出的缓冲区。在wl_closure_send这个函数中会调用wl_connection_write向wl_connection写入数据。
third_party\wayland_standard\src\connection.c
int
wl_closure_send(struct wl_closure *closure, struct wl_connection *connection)
{
int size;
uint32_t buffer_size;
uint32_t *buffer;
int result;
if (copy_fds_to_connection(closure, connection))
return -1;
buffer_size = buffer_size_for_closure(closure);
buffer = zalloc(buffer_size * sizeof buffer[0]);
if (buffer == NULL)
return -1;
size = serialize_closure(closure, buffer, buffer_size);
if (size < 0) {
free(buffer);
return -1;
}
result = wl_connection_write(connection, buffer, size);
free(buffer);
return result;
}
在该函数中会通过wl_connection_flush向Client发送数据, 把connection中out buffer的request通过socket发出去
third_party\wayland_standard\src\connection.c
int
wl_connection_write(struct wl_connection *connection,
const void *data, size_t count)
{
if (connection->out.head - connection->out.tail +
count > ARRAY_LENGTH(connection->out.data)) {
connection->want_flush = 1;
if (wl_connection_flush(connection) < 0)
return -1;
}
if (wl_buffer_put(&connection->out, data, count) < 0)
return -1;
connection->want_flush = 1;
return 0;
}
那么，Client是怎么读取和处理这些event呢？ 首先Client端需要监听这个wl_proxy，这是通过调用wl_registry_add_listener()->wl_proxy_add_listener()设置的。然后在Client的主循环中会调用wl_display_dispatch，并在wl_display_dispatch_queue()中处理收到的event和发出out buffer中的request。在wl_display_dispatch_queue中，wl_display_read_events负责 从connection的in buffer中读出数据，转为wl_closure，插入到queue->event_list，等待后续处理。接着会调用wl_display_dispatch_queue_pending。
third_party\wayland_standard\src\wayland-client.c
WL_EXPORT int
wl_display_dispatch(struct wl_display *display)
{
return wl_display_dispatch_queue(display, &display->default_queue);
}
WL_EXPORT int
wl_display_dispatch_queue(struct wl_display *display,
struct wl_event_queue *queue)
{
int ret;
if (wl_display_prepare_read_queue(display, queue) == -1)
return wl_display_dispatch_queue_pending(display, queue);
while (true) {
ret = wl_display_flush(display);
if (ret != -1 || errno != EAGAIN)
break;
if (wl_display_poll(display, POLLOUT) == -1) {
wl_display_cancel_read(display);
return -1;
}
}
/* Don't stop if flushing hits an EPIPE; continue so we can read any
* protocol error that may have triggered it. */
if (ret < 0 && errno != EPIPE) {
wl_display_cancel_read(display);
return -1;
}
if (wl_display_poll(display, POLLIN) == -1) {
wl_display_cancel_read(display);
return -1;
}
if (wl_display_read_events(display) == -1)
return -1;
return wl_display_dispatch_queue_pending(display, queue);
}
在该函数中继续调用dispatch_queue。
third_party\wayland_standard\src\wayland-client.c
WL_EXPORT int
wl_display_dispatch_queue_pending(struct wl_display *display,
struct wl_event_queue *queue)
{
int ret;
pthread_mutex_lock(&display->mutex);
ret = dispatch_queue(display, queue);
pthread_mutex_unlock(&display->mutex);
return ret;
}
在该函数中会将前面插入到queue当中的event（wl_closure）依次拿出来处理调用dispatch_event。
third_party\wayland_standard\src\wayland-client.c
static int
dispatch_queue(struct wl_display *display, struct wl_event_queue *queue)
{
int count;
if (display->last_error)
goto err;
count = 0;
while (!wl_list_empty(&display->display_queue.event_list)) {
dispatch_event(display, &display->display_queue);
if (display->last_error)
goto err;
count++;
}
while (!wl_list_empty(&queue->event_list)) {
dispatch_event(display, queue);
if (display->last_error)
goto err;
count++;
}
return count;
err:
errno = display->last_error;
return -1;
}
在该函数中最后通过wl_closure_invoke()进行调用。
third_party\wayland_standard\src\wayland-client.c
static void
dispatch_event(struct wl_display *display, struct wl_event_queue *queue)
{
struct wl_closure *closure;
struct wl_proxy *proxy;
int opcode;
bool proxy_destroyed;
closure = wl_container_of(queue->event_list.next, closure, link);
wl_list_remove(&closure->link);
opcode = closure->opcode;
/* Verify that the receiving object is still valid by checking if has
* been destroyed by the application. */
validate_closure_objects(closure);
proxy = closure->proxy;
proxy_destroyed = !!(proxy->flags & WL_PROXY_FLAG_DESTROYED);
if (proxy_destroyed) {
destroy_queued_closure(closure);
return;
}
pthread_mutex_unlock(&display->mutex);
if (proxy->dispatcher) {
if (debug_client)
wl_closure_print(closure, &proxy->object, false);
wl_closure_dispatch(closure, proxy->dispatcher,
&proxy->object, opcode);
} else if (proxy->object.implementation) {
if (debug_client)
wl_closure_print(closure, &proxy->object, false);
wl_closure_invoke(closure, WL_CLOSURE_INVOKE_CLIENT,
&proxy->object, opcode, proxy->user_data);
}
pthread_mutex_lock(&display->mutex);
destroy_queued_closure(closure);
}
wl_closure_invoke其实是回调implementation指向的回调函数
third_party\wayland_standard\src\connection.c
void
wl_closure_invoke(struct wl_closure *closure, uint32_t flags,
struct wl_object *target, uint32_t opcode, void *data)
{
int count;
ffi_cif cif;
ffi_type *ffi_types[WL_CLOSURE_MAX_ARGS + 2];
void * ffi_args[WL_CLOSURE_MAX_ARGS + 2];
void (* const *implementation)(void);
count = arg_count_for_signature(closure->message->signature);
ffi_types[0] = &ffi_type_pointer;
ffi_args[0] = &data;
ffi_types[1] = &ffi_type_pointer;
ffi_args[1] = ⌖
convert_arguments_to_ffi(closure->message->signature, flags, closure->args,
count, ffi_types + 2, ffi_args + 2);
ffi_prep_cif(&cif, FFI_DEFAULT_ABI,
count + 2, &ffi_type_void, ffi_types);
implementation = target->implementation;
// OHOS fix: if listener function is not NULL, it will be call
if (implementation[opcode]) {
ffi_call(&cif, implementation[opcode], NULL, ffi_args);
}
wl_closure_clear_fds(closure);
}
在RegisterKeyboardListener中注册了各种回调函数OnKeyboardKeymap，OnKeyboardEnter，OnKeyboardLeave，OnKeyboardKey，OnKeyboardModifiers，OnKeyboardRepeatInfo。
foundation\graphic\standard\frameworks\wm\src\input_listener_manager.cpp
void InputListenerManager::RegisterKeyboardListener(uint32_t caps)
{
bool haveKeyboardCapability = !!(caps & WL_SEAT_CAPABILITY_KEYBOARD);
if (haveKeyboardCapability == true && keyboard == nullptr) {
static struct wl_keyboard_listener listener = {
OnKeyboardKeymap,
OnKeyboardEnter,
OnKeyboardLeave,
OnKeyboardKey,
OnKeyboardModifiers,
OnKeyboardRepeatInfo,
};
keyboard = wl_seat_get_keyboard(seat);
if (keyboard) {
if (g_PowerKeyHandler == nullptr) {
std::shared_ptr<AppExecFwk::EventRunner> powerKeyRunner =
AppExecFwk::EventRunner::Create(GLOBAL_ACTION_THREAD_NAME);
g_PowerKeyHandler = std::make_shared<AppExecFwk::EventHandler>(powerKeyRunner);
powerKeyRunner->Run();
}
wl_keyboard_add_listener(keyboard, &listener, nullptr);
}
}
if (haveKeyboardCapability == false && keyboard != nullptr) {
wl_keyboard_destroy(keyboard);
keyboard = nullptr;
}
}
这些回调函数要被调用，首先Client端需要监听这个wl_proxy，这时InputListenerManager通过RegisterKeyboardListener将回调函数注册到listener中，然后再调用wl_keyboard_add_listener。
out\ohos-arm-release\gen\third_party\wayland_standard\protocol\wayland-client-protocol.h
static inline int
wl_keyboard_add_listener(struct wl_keyboard *wl_keyboard,
const struct wl_keyboard_listener *listener, void *data)
{
return wl_proxy_add_listener((struct wl_proxy *) wl_keyboard,
(void (**)(void)) listener, data);
}
这是会通过wl_proxy_add_listener将回调函数放入到proxy->object.implementation中。也就是说wanland client接收到事件后最终会回调InputListenerManager注册的回调函数。
third_party\wayland_standard\src\wayland-client.c
WL_EXPORT int
wl_proxy_add_listener(struct wl_proxy *proxy,
void (**implementation)(void), void *data)
{
if (proxy->flags & WL_PROXY_FLAG_WRAPPER)
wl_abort("Proxy %p is a wrapper\n", proxy);
if (proxy->object.implementation || proxy->dispatcher) {
wl_log("proxy %p already has listener\n", proxy);
return -1;
}
proxy->object.implementation = implementation;
proxy->user_data = data;
return 0;
}
现在再看回调函数OnKeyboardKey，接着调用listener->keyboardKey。
foundation\graphic\standard\frameworks\wm\src\input_listener_manager.cpp
void OnKeyboardKey(void *, struct wl_keyboard *,
uint32_t serial, uint32_t time, uint32_t key, uint32_t s)
{
auto state = static_cast<KeyboardKeyState>(s);
// Handle Power key
WMLOGFD("key: %{public}d, state: %{public}d", key, state);
if (key == KEY_POWER && g_PowerKeyHandler != nullptr) {
HandlePowerKey(time, key, state);
return;
}
const auto &inputListeners = g_getFocus();
for (const auto &listener : inputListeners) {
if (listener->keyboardKey) {
listener->keyboardKey(listener->GetWindow(), serial, time, key, state);
}
}
}
从这个添加监听的函数可以看出，当调用keyboardKey的时候会调用KeyboardHandleKey。
foundation\graphic\standard\frameworks\wm\src\multimodal_listener_manager.cpp
sptr<MultimodalListener> MultimodalListenerManager::AddListener(void *window)
{
auto l = delegator.Dep<InputListenerManager>()->AddListener(window);
sptr<MultimodalListener> ml = new MultimodalListener(window);
ml->input = l;
l->pointerMotion = std::bind(&MultimodalListenerManager::PointerHandleMotion, this, POINTER_ENTER_ARG);
l->pointerButton = std::bind(&MultimodalListenerManager::PointerHandleButton, this, POINTER_BUTTON_ARG);
l->pointerFrame = std::bind(&MultimodalListenerManager::PointerHandleFrame, this, POINTER_FRAME_ARG);
l->pointerAxis = std::bind(&MultimodalListenerManager::PointerHandleAxis, this, POINTER_AXIS_ARG);
l->keyboardKey = std::bind(&MultimodalListenerManager::KeyboardHandleKey, this, KEYBOARD_KEY_ARG);
l->touchDown = std::bind(&MultimodalListenerManager::TouchHandleDown, this, TOUCH_DOWN_ARG);
l->touchUp = std::bind(&MultimodalListenerManager::TouchHandleUp, this, TOUCH_UP_ARG);
l->touchMotion = std::bind(&MultimodalListenerManager::TouchHandleMotion, this, TOUCH_MOTION_ARG);
l->touchFrame = std::bind(&MultimodalListenerManager::TouchHandleFrame, this, TOUCH_FRAME_ARG);
l->touchShape = std::bind(&MultimodalListenerManager::TouchHandleShape, this, TOUCH_SHAPE_ARG);
l->touchOrientation = std::bind(
&MultimodalListenerManager::TouchHandleOrientation, this, TOUCH_ORIENTATION_ARG);
if (windowCallback.find(window) == windowCallback.end()) {
windowCallback[window] = std::vector<sptr<MultimodalListener>>();
}
windowCallback[window].push_back(ml);
return ml;
}
在KeyboardHandleKey中会对按键信息进行处理，并且会把按键状态，键值，按键按下的时长这些值放入到KeyProperty结构体中，然后把KeyProperty封装成KeyEvent的数据结构中用于派发。
foundation\graphic\standard\frameworks\wm\src\multimodal_listener_manager.cpp
void MultimodalListenerManager::KeyboardHandleKey(void *data,
uint32_t serial, uint32_t time, uint32_t key, KeyboardKeyState state)
{
KeyEvent event;
struct MultimodalProperty multiProperty = {
.highLevelEvent = 0,
.uuid = "",
.sourceType = MultimodalEvent::KEYBOARD,
.occurredTime = time,
.deviceId = "",
.inputDeviceId = 0,
.isHighLevelEvent = false,
};
struct KeyProperty keyProperty = {
.isPressed = (state == KEYBOARD_KEY_STATE_PRESSED),
.keyCode = key,
.keyDownDuration = 0,
};
static uint32_t keyDownTime = 0;
if (state == KEYBOARD_KEY_STATE_PRESSED) {
keyDownTime = time;
} else {
keyProperty.keyDownDuration = time - keyDownTime;
}
constexpr uint32_t linuxKeyBack = 158;
if (key == linuxKeyBack) {
keyProperty.keyCode = KeyEvent::CODE_BACK;
}
event.Initialize(multiProperty, keyProperty);
const auto &mls = GetInputCallback(data);
for (const auto &ml : mls) {
if (ml->keyboardKeyCb) {
ml->keyboardKeyCb(event);
}
}
}
由于目前openharmony代码在ACE部分没有完全支持对按键事件的处理，所以下面分析对touch事件的处理。现在也可以看TouchHandleUp这个回调，这个函数会调用ml->onTouchCb，
foundation\graphic\standard\frameworks\wm\src\multimodal_listener_manager.cpp
void MultimodalListenerManager::TouchHandleUp(void *data, uint32_t serial, uint32_t time, int32_t id)
{
if (id < MAX_TOUCH_NUM) {
actionEventInfo.touchCount--;
actionEventInfo.isUp = true;
actionEventInfo.touchEventInfos[id].isRefreshed = true;
actionEventInfo.touchEventInfos[id].serial = serial;
actionEventInfo.touchEventInfos[id].currentTime = time;
}
void *window = nullptr;
if (id < MAX_TOUCH_NUM) {
window = touchWindows[id];
touchWindows[id] = nullptr;
}
WMLOGFD("window: %{public}p", window);
while (actionEventInfo.isUp || actionEventInfo.isDown || actionEventInfo.isMotion) {
TouchEvent touchEvent;
TouchEventEncap(actionEventInfo, touchEvent, MAX_TOUCH_NUM);
const auto &mls = GetInputCallback(data);
for (const auto &ml : mls) {
if (ml->onTouchCb) {
ml->onTouchCb(touchEvent);
}
}
}
}
通过RegistOnTouchCb注册的方式，最终会调用aceView->DispatchTouchEvent。
foundation\graphic\standard\frameworks\wm\src\client\window_manager_controller_client.cpp
void LayerControllerClient::RegistOnTouchCb(int id, funcOnTouch cb)
{
LOCK(mutex);
WMLOG_I("LayerControllerClient::%{public}s", __func__);
if (cb) {
WMLOG_I("LayerControllerClient::RegistOnTouchCb OK");
GET_WINDOWINFO_VOID(windowInfo, id);
windowInfo->mmiListener->onTouchCb = cb;
}
}
foundation\graphic\standard\frameworks\wm\src\client\window_manager.cpp
void Window::RegistOnTouchCb(funcOnTouch cb)
{
WMLOG_I("Window::RegistOnTouchCb start, windowid %{public}d", this->m_windowid);
LayerControllerClient::GetInstance()->RegistOnTouchCb(m_windowid, cb);
WMLOG_I("Window::RegistOnTouchCb end windowid %{public}d", this->m_windowid);
}
foundation\ace\ace_engine\adapter\ohos\cpp\ace_ability.cpp
auto&& touchEventCallback = [aceView = flutterAceView](OHOS::TouchEvent event) -> bool {
LOGD("RegistOnTouchCb touchEventCallback called");
return aceView->DispatchTouchEvent(aceView, event);
};
window->OnTouch(touchEventCallback);
在DispatchTouchEvent中，会根据事件类型分为mouse event和touch event，这里先分析touch event，所以最后会调用ProcessTouchEvent。
foundation\ace\ace_engine\adapter\ohos\cpp\flutter_ace_view.cpp
bool FlutterAceView::DispatchTouchEvent(FlutterAceView* view, OHOS::TouchEvent& touchEvent)
{
if (touchEvent.GetAction() == OHOS::TouchEvent::OTHER && touchEvent.GetSourceDevice() == OHOS::TouchEvent::MOUSE) {
// mouse event
std::shared_ptr<MultimodalEvent> multimodalEvent = touchEvent.GetMultimodalEvent();
OHOS::MouseEvent* mouseEvent = (OHOS::MouseEvent*)multimodalEvent.get();
if (mouseEvent == nullptr) {
LOGE("mouseEvent is nullptr");
return false;
}
LOGI("DispatchTouchEvent MouseEvent");
view->ProcessMouseEvent(*mouseEvent);
} else {
// touch event
LOGI("DispatchTouchEvent TouchEvent");
return view->ProcessTouchEvent(touchEvent);
}
return true;
}
执行touchEventCallback_ 函数指针指向的函数，继续看touchEventCallback_ 指向了哪个函数。
foundation\ace\ace_engine\adapter\ohos\cpp\flutter_ace_view.cpp
bool FlutterAceView::ProcessTouchEvent(OHOS::TouchEvent& touchEvent)
{
TouchPoint touchPoint = ConvertTouchEvent(touchEvent);
bool forbiddenToPlatform = false;
if (touchPoint.type != TouchType::UNKNOWN) {
if (touchEventCallback_) {
touchEventCallback_(touchPoint);
}
} else {
LOGW("Unknown event.");
}
#ifdef WEARABLE_PRODUCT
forbiddenToPlatform = forbiddenToPlatform || IsNeedForbidToPlatform(point);
#endif
// if last page, let os know so that to quit app.
return forbiddenToPlatform || (!IsLastPage());
}
看来touchEventCallback_是指向了RegisterTouchEventCallback通过参数穿过来的callback, 那继续看调用RegisterTouchEventCallback的callback是什么。
foundation\ace\ace_engine\adapter\ohos\cpp\flutter_ace_view.cpp
void FlutterAceView::RegisterTouchEventCallback(TouchEventCallback&& callback)
{
ACE_DCHECK(callback);
touchEventCallback_ = std::move(callback);
}
在AceContainer::InitializeCallback中可以看出，最终这个callback就是执行pipeline_context的OnTouchEvent。
foundation\ace\ace_engine\adapter\ohos\cpp\ace_container.cpp
void AceContainer::InitializeCallback()
{
ACE_FUNCTION_TRACE();
ACE_DCHECK(aceView_ && taskExecutor_ && pipelineContext_);
auto&& touchEventCallback = [context = pipelineContext_](const TouchPoint& event) {
context->GetTaskExecutor()->PostTask(
[context, event]() { context->OnTouchEvent(event); }, TaskExecutor::TaskType::UI);
};
aceView_->RegisterTouchEventCallback(touchEventCallback);
在这个函数中最终会调用eventManager_.DispatchTouchEvent。之后就会通过ACE的接口把事件传给应用端。
foundation\ace\ace_engine\frameworks\core\pipeline\pipeline_context.cpp
void PipelineContext::OnTouchEvent(const TouchPoint& point)
{
CHECK_RUN_ON(UI);
ACE_FUNCTION_TRACE();
if (!rootElement_) {
LOGE("root element is nullptr");
return;
}
auto scalePoint = point.CreateScalePoint(viewScale_);
if (scalePoint.type == TouchType::DOWN) {
LOGD("receive touch down event, first use touch test to collect touch event target");
TouchRestrict touchRestrict { TouchRestrict::NONE };
auto frontEnd = GetFrontend();
if (frontEnd && (frontEnd->GetType() == FrontendType::JS_CARD)) {
touchRestrict.UpdateForbiddenType(TouchRestrict::LONG_PRESS);
}
eventManager_.TouchTest(scalePoint, rootElement_->GetRenderNode(), touchRestrict);
}
if (scalePoint.type == TouchType::MOVE) {
isMoving_ = true;
}
if (isKeyEvent_) {
SetIsKeyEvent(false);
}
eventManager_.DispatchTouchEvent(scalePoint);
}
总结
通过本篇文章的学习可以了解OpenHarmony L2系统基于wayland三方库的事件处理派发流程。
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感谢孙老师分享，非常详细的讲解。
太牛了，讲的太透彻了
框架讲解很清晰，收获颇多，感谢作者的分享，期待新的文章
孙老师真的是大佬, Input 这块能分析得这么透彻... 收藏下来对着源码慢慢学~
请教孙老师，这篇文章是基于哪个分支的哪个版本分析的啊？文中提到的源码有些找不到。
就贼详细