fix: Timeout unfulfilled request to decodingInfo and requestMediaKeySystemAccess (#7682)

On some (Android) WebView environments,
decodingInfo and requestMediaKeySystemAccess will
not resolve or reject, at least if RESOURCE_PROTECTED_MEDIA_ID is not
set.
This is a workaround for that issue.

Closes #7680

Author: CHaNGeTe

lib/media/drm_engine.js

@@ -15,6 +15,7 @@ goog.require('shaka.util.DrmUtils');
 goog.require('shaka.util.Error');
 goog.require('shaka.util.EventManager');
 goog.require('shaka.util.FakeEvent');
+goog.require('shaka.util.Functional');
 goog.require('shaka.util.IDestroyable');
 goog.require('shaka.util.Iterables');
 goog.require('shaka.util.ManifestParserUtils');
@@ -1859,9 +1860,16 @@ shaka.media.DrmEngine = class {
         offlineConfig.sessionTypes = ['persistent-license'];
 
         const configs = [offlineConfig, basicConfig];
-
-        const access = await navigator.requestMediaKeySystemAccess(
-            keySystem, configs);
+        // On some (Android) WebView environments,
+        // requestMediaKeySystemAccess will
+        // not resolve or reject, at least if RESOURCE_PROTECTED_MEDIA_ID
+        // is not set.  This is a workaround for that issue.
+        const TIMEOUT_FOR_CHECKACCESS_IN_SECONDS = 1;
+        const access =
+          await shaka.util.Functional.promiseWithTimeout(
+              TIMEOUT_FOR_CHECKACCESS_IN_SECONDS,
+              navigator.requestMediaKeySystemAccess(keySystem, configs),
+          );
         await processMediaKeySystemAccess(keySystem, access);
       } catch (error) {}  // Ignore errors.
     };
@@ -1896,13 +1904,22 @@ shaka.media.DrmEngine = class {
             },
           },
         };
-
+        // On some (Android) WebView environments, decodingInfo will
+        // not resolve or reject, at least if RESOURCE_PROTECTED_MEDIA_ID
+        // is not set.  This is a workaround for that issue.
+        const TIMEOUT_FOR_DECODING_INFO_IN_SECONDS = 1;
         const decodingInfo =
-            await navigator.mediaCapabilities.decodingInfo(decodingConfig);
+          await shaka.util.Functional.promiseWithTimeout(
+              TIMEOUT_FOR_DECODING_INFO_IN_SECONDS,
+              navigator.mediaCapabilities.decodingInfo(decodingConfig),
+          );
 
         const access = decodingInfo.keySystemAccess;
         await processMediaKeySystemAccess(keySystem, access);
-      } catch (error) {}  // Ignore errors.
+      } catch (error) {
+        // Ignore errors.
+        shaka.log.v2('Failed to probe support for', keySystem, error);
+      }
     };
 
     // Initialize the support structure for each key system.

lib/util/functional.js

@@ -6,6 +6,8 @@
 
 goog.provide('shaka.util.Functional');
 
+goog.require('shaka.util.Timer');
+
 /**
  * @summary A set of functional utility functions.
  */
@@ -67,4 +69,29 @@ shaka.util.Functional = class {
   static isNotNull(value) {
     return value != null;
   }
+
+  /**
+   * Returns a Promise which is resolved only if |asyncProcess| is resolved, and
+   * only if it is resolved in less than |seconds| seconds.
+   *
+   * If the returned Promise is resolved, it returns the same value as
+   * |asyncProcess|.
+   *
+   * If |asyncProcess| fails, the returned Promise is rejected.
+   * If |asyncProcess| takes too long, the returned Promise is rejected, but
+   * |asyncProcess| is still allowed to complete.
+   *
+   * @param {number} seconds
+   * @param {!Promise.<T>} asyncProcess
+   * @return {!Promise.<T>}
+   * @template T
+   */
+  static promiseWithTimeout(seconds, asyncProcess) {
+    return Promise.race([
+      asyncProcess,
+      new Promise(((_, reject) => {
+        new shaka.util.Timer(reject).tickAfter(seconds);
+      })),
+    ]);
+  }
 };

lib/util/stream_utils.js

@@ -727,7 +727,14 @@ shaka.util.StreamUtils = class {
               mimeType, audioCodec);
         }
         promises.push(new Promise((resolve, reject) => {
-          navigator.mediaCapabilities.decodingInfo(copy).then((res) => {
+          // On some (Android) WebView environments, decodingInfo will
+          // not resolve or reject, at least if RESOURCE_PROTECTED_MEDIA_ID
+          // is not set.  This is a workaround for that issue.
+          const TIMEOUT_FOR_DECODING_INFO_IN_SECONDS = 1;
+          shaka.util.Functional.promiseWithTimeout(
+              TIMEOUT_FOR_DECODING_INFO_IN_SECONDS,
+              navigator.mediaCapabilities.decodingInfo(copy),
+          ).then((res) => {
             resolve(res);
           }).catch(reject);
         }));

test/util/functional_unit.js

@@ -0,0 +1,34 @@
+/*! @license
+ * Shaka Player
+ * Copyright 2016 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+describe('Functional', () => {
+  const Functional = shaka.util.Functional;
+  describe('promiseWithTimeout', () => {
+    it('resolves if asyncProcess resolves within the timeout', async () => {
+      const asyncProcess = new Promise((resolve) =>
+        setTimeout(() => resolve('success'), 100),
+      );
+      const result = await Functional.promiseWithTimeout(1, asyncProcess);
+      expect(result).toBe('success');
+    });
+
+    it('rejects if asyncProcess rejects', async () => {
+      const asyncProcess = new Promise((_, reject) =>
+        setTimeout(() => reject('error'), 100),
+      );
+      const promise = Functional.promiseWithTimeout(1, asyncProcess);
+      await expectAsync(promise).toBeRejectedWith('error');
+    });
+
+    it('rejects if asyncProcess takes longer than the timeout', async () => {
+      const asyncProcess = new Promise((resolve) =>
+        setTimeout(() => resolve('success'), 2000),
+      );
+      const promise = Functional.promiseWithTimeout(1, asyncProcess);
+      await expectAsync(promise).toBeRejected();
+    });
+  });
+});