Extract HID events struct

An event contained several fields:
 - the accessory id
 - the HID event data
 - a field ack_to_wait specific to the AOA implementation.

Extract the HID event part to prepare the factorization of HID event
creation.

PR #4473 <https://github.com/Genymobile/scrcpy/pull/4473>

app/src/hid/hid_event.h

@@ -0,0 +1,15 @@
+#ifndef SC_HID_EVENT_H
+#define SC_HID_EVENT_H
+
+#include "common.h"
+
+#include <stdint.h>
+
+#define SC_HID_MAX_SIZE 8
+
+struct sc_hid_event {
+    uint8_t data[SC_HID_MAX_SIZE];
+    uint8_t size;
+};
+
+#endif

app/src/usb/aoa_hid.c

@@ -14,10 +14,10 @@
 
 #define DEFAULT_TIMEOUT 1000
 
-#define SC_HID_EVENT_QUEUE_MAX 64
+#define SC_AOA_EVENT_QUEUE_MAX 64
 
 static void
-sc_hid_event_log(const struct sc_hid_event *event) {
+sc_hid_event_log(uint16_t accessory_id, const struct sc_hid_event *event) {
     // HID Event: [00] FF FF FF FF...
     assert(event->size);
     unsigned buffer_size = event->size * 3 + 1;
@@ -29,7 +29,7 @@ sc_hid_event_log(const struct sc_hid_event *event) {
     for (unsigned i = 0; i < event->size; ++i) {
         snprintf(buffer + i * 3, 4, " %02x", event->data[i]);
     }
-    LOGV("HID Event: [%d]%s", event->accessory_id, buffer);
+    LOGV("HID Event: [%d]%s", accessory_id, buffer);
     free(buffer);
 }
 
@@ -38,7 +38,7 @@ sc_aoa_init(struct sc_aoa *aoa, struct sc_usb *usb,
             struct sc_acksync *acksync) {
     sc_vecdeque_init(&aoa->queue);
 
-    if (!sc_vecdeque_reserve(&aoa->queue, SC_HID_EVENT_QUEUE_MAX)) {
+    if (!sc_vecdeque_reserve(&aoa->queue, SC_AOA_EVENT_QUEUE_MAX)) {
         return false;
     }
 
@@ -150,13 +150,14 @@ sc_aoa_setup_hid(struct sc_aoa *aoa, uint16_t accessory_id,
 }
 
 static bool
-sc_aoa_send_hid_event(struct sc_aoa *aoa, const struct sc_hid_event *event) {
+sc_aoa_send_hid_event(struct sc_aoa *aoa, uint16_t accessory_id,
+                      const struct sc_hid_event *event) {
     uint8_t request_type = LIBUSB_ENDPOINT_OUT | LIBUSB_REQUEST_TYPE_VENDOR;
     uint8_t request = ACCESSORY_SEND_HID_EVENT;
     // <https://source.android.com/devices/accessories/aoa2.html#hid-support>
     // value (arg0): accessory assigned ID for the HID device
     // index (arg1): 0 (unused)
-    uint16_t value = event->accessory_id;
+    uint16_t value = accessory_id;
     uint16_t index = 0;
     unsigned char *data = (uint8_t *) event->data; // discard const
     uint16_t length = event->size;
@@ -173,7 +174,7 @@ sc_aoa_send_hid_event(struct sc_aoa *aoa, const struct sc_hid_event *event) {
 }
 
 bool
-sc_aoa_unregister_hid(struct sc_aoa *aoa, const uint16_t accessory_id) {
+sc_aoa_unregister_hid(struct sc_aoa *aoa, uint16_t accessory_id) {
     uint8_t request_type = LIBUSB_ENDPOINT_OUT | LIBUSB_REQUEST_TYPE_VENDOR;
     uint8_t request = ACCESSORY_UNREGISTER_HID;
     // <https://source.android.com/devices/accessories/aoa2.html#hid-support>
@@ -196,16 +197,25 @@ sc_aoa_unregister_hid(struct sc_aoa *aoa, const uint16_t accessory_id) {
 }
 
 bool
-sc_aoa_push_hid_event(struct sc_aoa *aoa, const struct sc_hid_event *event) {
+sc_aoa_push_hid_event_with_ack_to_wait(struct sc_aoa *aoa,
+                                       uint16_t accessory_id,
+                                       const struct sc_hid_event *event,
+                                       uint64_t ack_to_wait) {
     if (sc_get_log_level() <= SC_LOG_LEVEL_VERBOSE) {
-        sc_hid_event_log(event);
+        sc_hid_event_log(accessory_id, event);
     }
 
     sc_mutex_lock(&aoa->mutex);
     bool full = sc_vecdeque_is_full(&aoa->queue);
     if (!full) {
         bool was_empty = sc_vecdeque_is_empty(&aoa->queue);
-        sc_vecdeque_push_noresize(&aoa->queue, *event);
+
+        struct sc_aoa_event *aoa_event =
+            sc_vecdeque_push_hole_noresize(&aoa->queue);
+        aoa_event->hid = *event;
+        aoa_event->accessory_id = accessory_id;
+        aoa_event->ack_to_wait = ack_to_wait;
+
         if (was_empty) {
             sc_cond_signal(&aoa->event_cond);
         }
@@ -233,7 +243,7 @@ run_aoa_thread(void *data) {
         }
 
         assert(!sc_vecdeque_is_empty(&aoa->queue));
-        struct sc_hid_event event = sc_vecdeque_pop(&aoa->queue);
+        struct sc_aoa_event event = sc_vecdeque_pop(&aoa->queue);
         uint64_t ack_to_wait = event.ack_to_wait;
         sc_mutex_unlock(&aoa->mutex);
 
@@ -259,7 +269,7 @@ run_aoa_thread(void *data) {
             }
         }
 
-        bool ok = sc_aoa_send_hid_event(aoa, &event);
+        bool ok = sc_aoa_send_hid_event(aoa, event.accessory_id, &event.hid);
         if (!ok) {
             LOGW("Could not send HID event to USB device");
         }

app/src/usb/aoa_hid.h

@@ -6,6 +6,7 @@
 
 #include <libusb-1.0/libusb.h>
 
+#include "hid/hid_event.h"
 #include "usb.h"
 #include "util/acksync.h"
 #include "util/thread.h"
@@ -14,14 +15,13 @@
 
 #define SC_HID_MAX_SIZE 8
 
-struct sc_hid_event {
+struct sc_aoa_event {
+    struct sc_hid_event hid;
     uint16_t accessory_id;
-    uint8_t data[SC_HID_MAX_SIZE];
-    uint8_t size;
     uint64_t ack_to_wait;
 };
 
-struct sc_hid_event_queue SC_VECDEQUE(struct sc_hid_event);
+struct sc_aoa_event_queue SC_VECDEQUE(struct sc_aoa_event);
 
 struct sc_aoa {
     struct sc_usb *usb;
@@ -29,7 +29,7 @@ struct sc_aoa {
     sc_mutex mutex;
     sc_cond event_cond;
     bool stopped;
-    struct sc_hid_event_queue queue;
+    struct sc_aoa_event_queue queue;
 
     struct sc_acksync *acksync;
 };
@@ -57,6 +57,16 @@ bool
 sc_aoa_unregister_hid(struct sc_aoa *aoa, uint16_t accessory_id);
 
 bool
-sc_aoa_push_hid_event(struct sc_aoa *aoa, const struct sc_hid_event *event);
+sc_aoa_push_hid_event_with_ack_to_wait(struct sc_aoa *aoa,
+                                       uint16_t accessory_id,
+                                       const struct sc_hid_event *event,
+                                       uint64_t ack_to_wait);
+
+static inline bool
+sc_aoa_push_hid_event(struct sc_aoa *aoa, uint16_t accessory_id,
+                      const struct sc_hid_event *event) {
+    return sc_aoa_push_hid_event_with_ack_to_wait(aoa, accessory_id, event,
+                                                  SC_SEQUENCE_INVALID);
+}
 
 #endif

app/src/usb/hid_keyboard.c

@@ -233,9 +233,7 @@ sdl_keymod_to_hid_modifiers(uint16_t mod) {
 
 static void
 sc_hid_keyboard_event_init(struct sc_hid_event *hid_event) {
-    hid_event->accessory_id = HID_KEYBOARD_ACCESSORY_ID;
     hid_event->size = HID_KEYBOARD_EVENT_SIZE;
-    hid_event->ack_to_wait = SC_SEQUENCE_INVALID;
 
     uint8_t *data = hid_event->data;
 
@@ -329,7 +327,8 @@ push_mod_lock_state(struct sc_hid_keyboard *kb, uint16_t mods_state) {
         ++i;
     }
 
-    if (!sc_aoa_push_hid_event(kb->aoa, &hid_event)) {
+    if (!sc_aoa_push_hid_event(kb->aoa, HID_KEYBOARD_ACCESSORY_ID,
+                               &hid_event)) {
         LOGW("Could not request HID event (mod lock state)");
         return false;
     }
@@ -362,15 +361,15 @@ sc_key_processor_process_key(struct sc_key_processor *kp,
             }
         }
 
-        if (ack_to_wait) {
-            // Ctrl+v is pressed, so clipboard synchronization has been
-            // requested. Wait until clipboard synchronization is acknowledged
-            // by the server, otherwise it could paste the old clipboard
-            // content.
-            hid_event.ack_to_wait = ack_to_wait;
-        }
+        // If ack_to_wait is != SC_SEQUENCE_INVALID, then Ctrl+v is pressed, so
+        // clipboard synchronization has been requested. Wait until clipboard
+        // synchronization is acknowledged by the server, otherwise it could
+        // paste the old clipboard content.
 
-        if (!sc_aoa_push_hid_event(kb->aoa, &hid_event)) {
+        if (!sc_aoa_push_hid_event_with_ack_to_wait(kb->aoa,
+                                                    HID_KEYBOARD_ACCESSORY_ID,
+                                                    &hid_event,
+                                                    ack_to_wait)) {
             LOGW("Could not request HID event (key)");
         }
     }

app/src/usb/hid_mouse.c

@@ -133,9 +133,7 @@ static const unsigned char mouse_report_desc[]  = {
 
 static void
 sc_hid_mouse_event_init(struct sc_hid_event *hid_event) {
-    hid_event->accessory_id = HID_MOUSE_ACCESSORY_ID;
     hid_event->size = HID_MOUSE_EVENT_SIZE;
-    hid_event->ack_to_wait = SC_SEQUENCE_INVALID;
     // Leave hid_event->data uninitialized, it will be fully initialized by
     // callers
 }
@@ -175,7 +173,8 @@ sc_mouse_processor_process_mouse_motion(struct sc_mouse_processor *mp,
     data[2] = CLAMP(event->yrel, -127, 127);
     data[3] = 0; // wheel coordinates only used for scrolling
 
-    if (!sc_aoa_push_hid_event(mouse->aoa, &hid_event)) {
+    if (!sc_aoa_push_hid_event(mouse->aoa, HID_MOUSE_ACCESSORY_ID,
+                               &hid_event)) {
         LOGW("Could not request HID event (mouse motion)");
     }
 }
@@ -194,7 +193,8 @@ sc_mouse_processor_process_mouse_click(struct sc_mouse_processor *mp,
     data[2] = 0; // no y motion
     data[3] = 0; // wheel coordinates only used for scrolling
 
-    if (!sc_aoa_push_hid_event(mouse->aoa, &hid_event)) {
+    if (!sc_aoa_push_hid_event(mouse->aoa, HID_MOUSE_ACCESSORY_ID,
+                               &hid_event)) {
         LOGW("Could not request HID event (mouse click)");
     }
 }
@@ -216,7 +216,8 @@ sc_mouse_processor_process_mouse_scroll(struct sc_mouse_processor *mp,
     data[3] = CLAMP(event->vscroll, -127, 127);
     // Horizontal scrolling ignored
 
-    if (!sc_aoa_push_hid_event(mouse->aoa, &hid_event)) {
+    if (!sc_aoa_push_hid_event(mouse->aoa, HID_MOUSE_ACCESSORY_ID,
+                               &hid_event)) {
         LOGW("Could not request HID event (mouse scroll)");
     }
 }