Extract USB handling from AOA

The AOA code handled both USB initialization and AOA commands/events.
Extract USB-related code to a separate file and structure.

PR #2974 <https://github.com/Genymobile/scrcpy/pull/2974>

app/src/usb/aoa_hid.c

@@ -50,74 +50,6 @@ log_libusb_error(enum libusb_error errcode) {
     LOGW("libusb error: %s", libusb_strerror(errcode));
 }
 
-static bool
-accept_device(libusb_device *device, const char *serial) {
-    // do not log any USB error in this function, it is expected that many USB
-    // devices available on the computer have permission restrictions
-
-    struct libusb_device_descriptor desc;
-    int result = libusb_get_device_descriptor(device, &desc);
-    if (result < 0 || !desc.iSerialNumber) {
-        return false;
-    }
-
-    libusb_device_handle *handle;
-    result = libusb_open(device, &handle);
-    if (result < 0) {
-        return false;
-    }
-
-    char buffer[128];
-    result = libusb_get_string_descriptor_ascii(handle, desc.iSerialNumber,
-                                                (unsigned char *) buffer,
-                                                sizeof(buffer));
-    libusb_close(handle);
-    if (result < 0) {
-        return false;
-    }
-
-    buffer[sizeof(buffer) - 1] = '\0'; // just in case
-
-    // accept the device if its serial matches
-    return !strcmp(buffer, serial);
-}
-
-static libusb_device *
-sc_aoa_find_usb_device(const char *serial) {
-    if (!serial) {
-        return NULL;
-    }
-
-    libusb_device **list;
-    libusb_device *result = NULL;
-    ssize_t count = libusb_get_device_list(NULL, &list);
-    if (count < 0) {
-        log_libusb_error((enum libusb_error) count);
-        return NULL;
-    }
-
-    for (size_t i = 0; i < (size_t) count; ++i) {
-        libusb_device *device = list[i];
-
-        if (accept_device(device, serial)) {
-            result = libusb_ref_device(device);
-            break;
-        }
-    }
-    libusb_free_device_list(list, 1);
-    return result;
-}
-
-static int
-sc_aoa_open_usb_handle(libusb_device *device, libusb_device_handle **handle) {
-    int result = libusb_open(device, handle);
-    if (result < 0) {
-        log_libusb_error((enum libusb_error) result);
-        return result;
-    }
-    return 0;
-}
-
 bool
 sc_aoa_init(struct sc_aoa *aoa, const char *serial,
             struct sc_acksync *acksync) {
@@ -133,31 +65,16 @@ sc_aoa_init(struct sc_aoa *aoa, const char *serial,
         goto error_destroy_mutex;
     }
 
-    if (libusb_init(&aoa->usb_context) != LIBUSB_SUCCESS) {
+    bool ok = sc_usb_init(&aoa->usb, serial);
+    if (!ok) {
         goto error_destroy_cond;
     }
 
-    aoa->usb_device = sc_aoa_find_usb_device(serial);
-    if (!aoa->usb_device) {
-        LOGW("USB device of serial %s not found", serial);
-        goto error_exit_libusb;
-    }
-
-    if (sc_aoa_open_usb_handle(aoa->usb_device, &aoa->usb_handle) < 0) {
-        LOGW("Open USB handle failed");
-        goto error_unref_device;
-        return false;
-    }
-
     aoa->stopped = false;
     aoa->acksync = acksync;
 
     return true;
 
-error_unref_device:
-    libusb_unref_device(aoa->usb_device);
-error_exit_libusb:
-    libusb_exit(aoa->usb_context);
 error_destroy_cond:
     sc_cond_destroy(&aoa->event_cond);
 error_destroy_mutex:
@@ -173,9 +90,7 @@ sc_aoa_destroy(struct sc_aoa *aoa) {
         sc_hid_event_destroy(&event);
     }
 
-    libusb_close(aoa->usb_handle);
-    libusb_unref_device(aoa->usb_device);
-    libusb_exit(aoa->usb_context);
+    sc_usb_destroy(&aoa->usb);
     sc_cond_destroy(&aoa->event_cond);
     sc_mutex_destroy(&aoa->mutex);
 }
@@ -192,7 +107,7 @@ sc_aoa_register_hid(struct sc_aoa *aoa, uint16_t accessory_id,
     uint16_t index = report_desc_size;
     unsigned char *buffer = NULL;
     uint16_t length = 0;
-    int result = libusb_control_transfer(aoa->usb_handle, request_type, request,
+    int result = libusb_control_transfer(aoa->usb.handle, request_type, request,
                                          value, index, buffer, length,
                                          DEFAULT_TIMEOUT);
     if (result < 0) {
@@ -228,7 +143,7 @@ sc_aoa_set_hid_report_desc(struct sc_aoa *aoa, uint16_t accessory_id,
     // libusb_control_transfer expects a pointer to non-const
     unsigned char *buffer = (unsigned char *) report_desc;
     uint16_t length = report_desc_size;
-    int result = libusb_control_transfer(aoa->usb_handle, request_type, request,
+    int result = libusb_control_transfer(aoa->usb.handle, request_type, request,
                                          value, index, buffer, length,
                                          DEFAULT_TIMEOUT);
     if (result < 0) {
@@ -270,7 +185,7 @@ sc_aoa_send_hid_event(struct sc_aoa *aoa, const struct sc_hid_event *event) {
     uint16_t index = 0;
     unsigned char *buffer = event->buffer;
     uint16_t length = event->size;
-    int result = libusb_control_transfer(aoa->usb_handle, request_type, request,
+    int result = libusb_control_transfer(aoa->usb.handle, request_type, request,
                                          value, index, buffer, length,
                                          DEFAULT_TIMEOUT);
     if (result < 0) {
@@ -292,7 +207,7 @@ sc_aoa_unregister_hid(struct sc_aoa *aoa, const uint16_t accessory_id) {
     uint16_t index = 0;
     unsigned char *buffer = NULL;
     uint16_t length = 0;
-    int result = libusb_control_transfer(aoa->usb_handle, request_type, request,
+    int result = libusb_control_transfer(aoa->usb.handle, request_type, request,
                                          value, index, buffer, length,
                                          DEFAULT_TIMEOUT);
     if (result < 0) {