dom/media/eme/CDMCaps.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "mozilla/CDMCaps.h"
   8 #include "mozilla/EMEUtils.h"
   9 #include "nsThreadUtils.h"
  10 #include "SamplesWaitingForKey.h"
  11
  12 namespace mozilla {
  13
  14 CDMCaps::CDMCaps() = default;
  15
  16 CDMCaps::~CDMCaps() = default;
  17
  18 // Keys with MediaKeyStatus::Usable, MediaKeyStatus::Output_downscaled,
  19 // or MediaKeyStatus::Output_restricted status can be used by the CDM
  20 // to decrypt or decrypt-and-decode samples.
  21 static bool IsUsableStatus(dom::MediaKeyStatus aStatus) {
  22   return aStatus == dom::MediaKeyStatus::Usable ||
  23          aStatus == dom::MediaKeyStatus::Output_restricted ||
  24          aStatus == dom::MediaKeyStatus::Output_downscaled;
  25 }
  26
  27 bool CDMCaps::IsKeyUsable(const CencKeyId& aKeyId) {
  28   for (const KeyStatus& keyStatus : mKeyStatuses) {
  29     if (keyStatus.mId == aKeyId) {
  30       return IsUsableStatus(keyStatus.mStatus);
  31     }
  32   }
  33   return false;
  34 }
  35
  36 bool CDMCaps::SetKeyStatus(const CencKeyId& aKeyId, const nsString& aSessionId,
  37                            const dom::Optional<dom::MediaKeyStatus>& aStatus) {
  38   if (!aStatus.WasPassed()) {
  39     // Called from ForgetKeyStatus.
  40     // Return true if the element is found to notify key changes.
  41     return mKeyStatuses.RemoveElement(
  42         KeyStatus(aKeyId, aSessionId, dom::MediaKeyStatus::Internal_error));
  43   }
  44
  45   KeyStatus key(aKeyId, aSessionId, aStatus.Value());
  46   auto index = mKeyStatuses.IndexOf(key);
  47   if (index != mKeyStatuses.NoIndex) {
  48     if (mKeyStatuses[index].mStatus == aStatus.Value()) {
  49       // No change.
  50       return false;
  51     }
  52     auto oldStatus = mKeyStatuses[index].mStatus;
  53     mKeyStatuses[index].mStatus = aStatus.Value();
  54     // The old key status was one for which we can decrypt media. We don't
  55     // need to do the "notify usable" step below, as it should be impossible
  56     // for us to have anything waiting on this key to become usable, since it
  57     // was already usable.
  58     if (IsUsableStatus(oldStatus)) {
  59       return true;
  60     }
  61   } else {
  62     mKeyStatuses.AppendElement(key);
  63   }
  64
  65   // Only call NotifyUsable() for a key when we are going from non-usable
  66   // to usable state.
  67   if (!IsUsableStatus(aStatus.Value())) {
  68     return true;
  69   }
  70
  71   auto& waiters = mWaitForKeys;
  72   size_t i = 0;
  73   while (i < waiters.Length()) {
  74     auto& w = waiters[i];
  75     if (w.mKeyId == aKeyId) {
  76       w.mListener->NotifyUsable(aKeyId);
  77       waiters.RemoveElementAt(i);
  78     } else {
  79       i++;
  80     }
  81   }
  82   return true;
  83 }
  84
  85 void CDMCaps::NotifyWhenKeyIdUsable(const CencKeyId& aKey,
  86                                     SamplesWaitingForKey* aListener) {
  87   MOZ_ASSERT(!IsKeyUsable(aKey));
  88   MOZ_ASSERT(aListener);
  89   mWaitForKeys.AppendElement(WaitForKeys(aKey, aListener));
  90 }
  91
  92 void CDMCaps::GetKeyStatusesForSession(const nsAString& aSessionId,
  93                                        nsTArray<KeyStatus>& aOutKeyStatuses) {
  94   for (const KeyStatus& keyStatus : mKeyStatuses) {
  95     if (keyStatus.mSessionId.Equals(aSessionId)) {
  96       aOutKeyStatuses.AppendElement(keyStatus);
  97     }
  98   }
  99 }
 100
 101 bool CDMCaps::RemoveKeysForSession(const nsString& aSessionId) {
 102   bool changed = false;
 103   nsTArray<KeyStatus> statuses;
 104   GetKeyStatusesForSession(aSessionId, statuses);
 105   for (const KeyStatus& status : statuses) {
 106     changed |= SetKeyStatus(status.mId, aSessionId,
 107                             dom::Optional<dom::MediaKeyStatus>());
 108   }
 109   return changed;
 110 }
 111
 112 }  // namespace mozilla