Bug 1587522 - Add MediaKeySystemAccessPermissionRequest. r=alwu

This class will be used to surface permission requests to GeckoView.

Differential Revision: https://phabricator.services.mozilla.com/D56103

--HG--
extra : moz-landing-system : lando

dom/media/eme/MediaKeySystemAccessPermissionRequest.cpp

@@ -0,0 +1,94 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MediaKeySystemAccessPermissionRequest.h"
+
+#include "nsGlobalWindowInner.h"
+
+namespace mozilla {
+namespace dom {
+
+NS_IMPL_CYCLE_COLLECTION_INHERITED(MediaKeySystemAccessPermissionRequest,
+                                   ContentPermissionRequestBase)
+
+NS_IMPL_ISUPPORTS_CYCLE_COLLECTION_INHERITED_0(
+    MediaKeySystemAccessPermissionRequest, ContentPermissionRequestBase)
+
+/* static */
+already_AddRefed<MediaKeySystemAccessPermissionRequest>
+MediaKeySystemAccessPermissionRequest::Create(nsPIDOMWindowInner* aWindow) {
+  // Could conceivably be created off main thread then used on main thread
+  // later. If we really need to do that at some point we could relax this
+  // assert.
+  AssertIsOnMainThread();
+  if (!aWindow) {
+    return nullptr;
+  }
+
+  nsGlobalWindowInner* innerWindow = nsGlobalWindowInner::Cast(aWindow);
+  if (!innerWindow->GetPrincipal()) {
+    return nullptr;
+  }
+
+  RefPtr<MediaKeySystemAccessPermissionRequest> request =
+      new MediaKeySystemAccessPermissionRequest(innerWindow);
+  return request.forget();
+}
+
+MediaKeySystemAccessPermissionRequest::MediaKeySystemAccessPermissionRequest(
+    nsGlobalWindowInner* aWindow)
+    : ContentPermissionRequestBase(
+          aWindow->GetPrincipal(), aWindow,
+          NS_LITERAL_CSTRING("media.eme.require-app-approval"),
+          NS_LITERAL_CSTRING("media-key-system-access")) {}
+
+MediaKeySystemAccessPermissionRequest::
+    ~MediaKeySystemAccessPermissionRequest() {
+  AssertIsOnMainThread();
+  // If a request has not been serviced by the time it is destroyed, treat it
+  // as if the request was denied.
+  Cancel();
+}
+
+already_AddRefed<MediaKeySystemAccessPermissionRequest::RequestPromise>
+MediaKeySystemAccessPermissionRequest::GetPromise() {
+  return mPromiseHolder.Ensure(__func__);
+}
+
+nsresult MediaKeySystemAccessPermissionRequest::Start() {
+  // Check test prefs to see if we should short circuit. We want to do this
+  // before checking the cached value so we can have pref changes take effect
+  // without refreshing the page.
+  MediaKeySystemAccessPermissionRequest::PromptResult promptResult =
+      CheckPromptPrefs();
+  if (promptResult ==
+      MediaKeySystemAccessPermissionRequest::PromptResult::Granted) {
+    return Allow(JS::UndefinedHandleValue);
+  }
+  if (promptResult ==
+      MediaKeySystemAccessPermissionRequest::PromptResult::Denied) {
+    return Cancel();
+  }
+
+  return nsContentPermissionUtils::AskPermission(this, mWindow);
+}
+
+NS_IMETHODIMP
+MediaKeySystemAccessPermissionRequest::Allow(JS::HandleValue aChoices) {
+  AssertIsOnMainThread();
+  mPromiseHolder.ResolveIfExists(true, __func__);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+MediaKeySystemAccessPermissionRequest::Cancel() {
+  AssertIsOnMainThread();
+  mPromiseHolder.RejectIfExists(false, __func__);
+  return NS_OK;
+}
+
+}  // namespace dom
+}  // namespace mozilla

dom/media/eme/MediaKeySystemAccessPermissionRequest.h

@@ -0,0 +1,74 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef DOM_MEDIA_EME_MEDIAKEYSYSTEMACCESSPERMISSIONREQUEST_H_
+#define DOM_MEDIA_EME_MEDIAKEYSYSTEMACCESSPERMISSIONREQUEST_H_
+
+#include "mozilla/MozPromise.h"
+#include "nsContentPermissionHelper.h"
+
+namespace mozilla {
+namespace dom {
+
+/**
+ * This class encapsulates a permission request to allow media key system
+ * access. The intention is not for this class to be used in all cases of EME,
+ * but only when we need to seek explicit approval from an application using
+ * Gecko, such as an application embedding via GeckoView.
+ *
+ * media.eme.require-app-approval should be used to gate this functionality in
+ * gecko code, and is also used as the testing pref for
+ * ContentPermissionRequestBase. I.e. CheckPromptPrefs() will respond to having
+ * `media.eme.require-app-approval.prompt.testing` and
+ * `media.eme.require-app-approval.prompt.testing.allow` being set to true or
+ * false and will return an appropriate value to allow for test code to short
+ * circuit showing a prompt. Note that the code using this class needs to call
+ * CheckPromptPrefs and implement test specific logic, it is *not* handled by
+ * this class or ContentPermissionRequestBase.
+ *
+ * Expects to be used on main thread as ContentPermissionRequestBase uses
+ * PContentPermissionRequest which is managed by PContent which is main thread
+ * to main thread communication.
+ */
+class MediaKeySystemAccessPermissionRequest
+    : public ContentPermissionRequestBase {
+ public:
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(
+      MediaKeySystemAccessPermissionRequest, ContentPermissionRequestBase)
+
+  using RequestPromise = MozPromise<bool, bool, true /* IsExclusive*/>;
+
+  // Create a MediaKeySystemAccessPermissionRequest.
+  // @param aWindow The window associated with this request.
+  static already_AddRefed<MediaKeySystemAccessPermissionRequest> Create(
+      nsPIDOMWindowInner* aWindow);
+
+  // Returns a promise that will be resolved if this request is allowed or
+  // rejected in the case the request is denied. If allowed the promise
+  // will resolve with true, otherwise it will resolve with false.
+  already_AddRefed<RequestPromise> GetPromise();
+
+  // Helper function that triggers the request. This function will check
+  // prefs and cancel or allow the request if the appropriate prefs are set,
+  // otherwise it will fire the request to the associated window.
+  nsresult Start();
+
+  // nsIContentPermissionRequest methods
+  NS_IMETHOD Cancel(void) override;
+  NS_IMETHOD Allow(JS::HandleValue choices) override;
+
+ private:
+  explicit MediaKeySystemAccessPermissionRequest(nsGlobalWindowInner* aWindow);
+  ~MediaKeySystemAccessPermissionRequest();
+
+  MozPromiseHolder<RequestPromise> mPromiseHolder;
+};
+
+}  // namespace dom
+}  // namespace mozilla
+
+#endif  // DOM_MEDIA_EME_MEDIAKEYSYSTEMACCESSPERMISSIONREQUEST_H_

dom/media/eme/moz.build

@@ -13,6 +13,7 @@ EXPORTS.mozilla.dom += [
     'MediaKeyStatusMap.h',
     'MediaKeySystemAccess.h',
     'MediaKeySystemAccessManager.h',
+    'MediaKeySystemAccessPermissionRequest.h',
 ]
 
 EXPORTS.mozilla += [
@@ -35,6 +36,7 @@ UNIFIED_SOURCES += [
     'MediaKeyStatusMap.cpp',
     'MediaKeySystemAccess.cpp',
     'MediaKeySystemAccessManager.cpp',
+    'MediaKeySystemAccessPermissionRequest.cpp',
 ]
 
 if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'android':