Handle opening and closing devices

packages/snaps-controllers/src/devices/DeviceController.ts

@@ -25,8 +25,10 @@ import type {
   WriteDeviceParams,
 } from '@metamask/snaps-sdk';
 import { DeviceType } from '@metamask/snaps-sdk';
+import { logError } from '@metamask/snaps-utils';
 import { assert, createDeferredPromise, hasProperty } from '@metamask/utils';
 
+import { CLOSE_DEVICE_TIMEOUT } from './constants';
 import { HIDManager } from './implementations';
 import type { SnapDevice } from './implementations/device';
 import type { DeviceManager } from './implementations/device-manager';
@@ -98,11 +100,6 @@ export type DeviceControllerMessenger = RestrictedControllerMessenger<
   DeviceControllerAllowedEvents['type']
 >;
 
-export type ConnectedDevice = {
-  reference: any; // TODO: Type this
-  metadata: Device;
-};
-
 export type DeviceControllerState = {
   devices: Record<string, Device>;
   pairing: {
@@ -136,6 +133,8 @@ export class DeviceController extends BaseController<
 
   #devices: Record<DeviceId, SnapDevice> = {};
 
+  #timeouts: Record<DeviceId, NodeJS.Timeout> = {};
+
   constructor({ messenger, state }: DeviceControllerArgs) {
     super({
       messenger,
@@ -240,6 +239,7 @@ export class DeviceController extends BaseController<
     const device = this.#devices[id];
     assert(device, 'Device not found.');
 
+    await this.#openDevice(id);
     await device.write(params);
 
     return null;
@@ -255,6 +255,7 @@ export class DeviceController extends BaseController<
     const device = this.#devices[id];
     assert(device, 'Device not found.');
 
+    await this.#openDevice(id);
     return await device.read(params);
   }
 
@@ -346,4 +347,45 @@ export class DeviceController extends BaseController<
       draftState.pairing = null;
     });
   }
+
+  /**
+   * Open a device, and set a timeout to close it if it is not used.
+   *
+   * @param id - The ID of the device to open.
+   * @returns A promise that resolves when the device is opened.
+   */
+  async #openDevice(id: DeviceId) {
+    const device = this.#devices[id];
+    assert(device, 'Device not found.');
+
+    await device.open();
+
+    if (this.#timeouts[id]) {
+      clearTimeout(this.#timeouts[id]);
+    }
+
+    this.#timeouts[id] = setTimeout(() => {
+      this.#closeDevice(id).catch((error) => {
+        logError('Failed to close device.', error);
+      });
+    }, CLOSE_DEVICE_TIMEOUT);
+  }
+
+  /**
+   * Close a device.
+   *
+   * @param id - The ID of the device to close.
+   * @returns A promise that resolves when the device is closed.
+   */
+  async #closeDevice(id: DeviceId) {
+    const device = this.#devices[id];
+    assert(device, 'Device not found.');
+
+    if (this.#timeouts[id]) {
+      clearTimeout(this.#timeouts[id]);
+      delete this.#timeouts[id];
+    }
+
+    await device.close();
+  }
 }

packages/snaps-controllers/src/devices/constants.ts

@@ -0,0 +1,3 @@
+import { Duration, inMilliseconds } from '@metamask/utils';
+
+export const CLOSE_DEVICE_TIMEOUT = inMilliseconds(5, Duration.Second);

packages/snaps-controllers/src/devices/implementations/device.ts

@@ -50,6 +50,11 @@ export abstract class SnapDevice extends TypedEventEmitter<SnapDeviceEvents> {
    */
   abstract write(params: WriteDeviceParams): Promise<void>;
 
+  /**
+   * Open the connection to the device.
+   */
+  abstract open(): Promise<void>;
+
   /**
    * Close the connection to the device.
    */

packages/snaps-controllers/src/devices/implementations/hid.ts

@@ -66,6 +66,7 @@ export class HIDSnapDevice extends SnapDevice {
    */
   async read({ type, reportType = 'output', reportId = 0 }: ReadDeviceParams) {
     assert(type === this.type);
+    assert(this.#device.opened, 'Device is not open.');
 
     if (reportType === 'feature') {
       const view = await this.#device.receiveFeatureReport(reportId);
@@ -102,6 +103,7 @@ export class HIDSnapDevice extends SnapDevice {
     data,
   }: WriteDeviceParams) {
     assert(type === this.type);
+    assert(this.#device.opened, 'Device is not open.');
 
     const buffer = hexToBytes(data);
     if (reportType === 'feature') {
@@ -111,10 +113,21 @@ export class HIDSnapDevice extends SnapDevice {
     return await this.#device.sendReport(reportId, buffer);
   }
 
+  /**
+   * Open the connection to the device.
+   */
+  async open() {
+    if (!this.#device.opened) {
+      await this.#device.open();
+    }
+  }
+
   /**
    * Close the connection to the device.
    */
   async close() {
-    await this.#device.close();
+    if (this.#device.opened) {
+      await this.#device.close();
+    }
   }
 }