From 0451648c60831f8cfc1bf5f2eb232e86e6373d68 Mon Sep 17 00:00:00 2001
From: Moonchild <moonchild@palemoon.org>
Date: Tue, 17 Oct 2023 13:31:40 +0200
Subject: Issue #2346 - Remove MDSM "Wait for CDM" state

Without EME we don't need the machinery to wait for an external
CDM module to be ready in our mediadecoder.
---
 dom/media/MediaDecoderStateMachine.cpp | 82 +---------------------------------
 dom/media/MediaDecoderStateMachine.h   |  2 -
 2 files changed, 2 insertions(+), 82 deletions(-)

diff --git a/dom/media/MediaDecoderStateMachine.cpp b/dom/media/MediaDecoderStateMachine.cpp
index 218bddc4ac..dc82e89e34 100644
--- a/dom/media/MediaDecoderStateMachine.cpp
+++ b/dom/media/MediaDecoderStateMachine.cpp
@@ -271,7 +271,6 @@ protected:
  *
  * Transition to other states when decoding metadata is done:
  *   SHUTDOWN if failing to decode metadata.
- *   WAIT_FOR_CDM if the media is encrypted and CDM is not available.
  *   DECODING_FIRSTFRAME otherwise.
  */
 class MediaDecoderStateMachine::DecodeMetadataState
@@ -341,60 +340,6 @@ private:
   MozPromiseRequestHolder<MediaDecoderReader::MetadataPromise> mMetadataRequest;
 };
 
-/**
- * Purpose: wait for the CDM to start decoding.
- *
- * Transition to other states when CDM is ready:
- *   DECODING_FIRSTFRAME otherwise.
- */
-class MediaDecoderStateMachine::WaitForCDMState
-  : public MediaDecoderStateMachine::StateObject
-{
-public:
-  explicit WaitForCDMState(Master* aPtr) : StateObject(aPtr) {}
-
-  void Enter()
-  {
-    MOZ_ASSERT(!mMaster->mVideoDecodeSuspended);
-  }
-
-  void Exit() override
-  {
-    // mPendingSeek is either moved in HandleCDMProxyReady() or should be
-    // rejected here before transition to SHUTDOWN.
-    mPendingSeek.RejectIfExists(__func__);
-  }
-
-  State GetState() const override
-  {
-    return DECODER_STATE_WAIT_FOR_CDM;
-  }
-
-  void HandleCDMProxyReady() override;
-
-  RefPtr<MediaDecoder::SeekPromise> HandleSeek(SeekTarget aTarget) override
-  {
-    SLOG("Not Enough Data to seek at this stage, queuing seek");
-    mPendingSeek.RejectIfExists(__func__);
-    mPendingSeek.mTarget = aTarget;
-    return mPendingSeek.mPromise.Ensure(__func__);
-  }
-
-  void HandleVideoSuspendTimeout() override
-  {
-    // Do nothing since no decoders are created yet.
-  }
-
-  void HandleResumeVideoDecoding() override
-  {
-    // We never suspend video decoding in this state.
-    MOZ_ASSERT(false, "Shouldn't have suspended video decoding.");
-  }
-
-private:
-  SeekJob mPendingSeek;
-};
-
 /**
  * Purpose: release decoder resources to save memory and hardware resources.
  *
@@ -1231,29 +1176,14 @@ DecodeMetadataState::OnMetadataRead(MetadataHolder* aMetadata)
          mMaster->GetAmpleVideoFrames());
   }
 
-  // In general, we wait until we know the duration before notifying the decoder.
-  // However, we notify  unconditionally in this case without waiting for the start
-  // time, since the caller might be waiting on metadataloaded to be fired before
-  // feeding in the CDM, which we need to decode the first frame (and
-  // thus get the metadata). We could fix this if we could compute the start
-  // time by demuxing without necessaring decoding.
-  bool waitingForCDM = 
-    false;
-
   mMaster->mNotifyMetadataBeforeFirstFrame =
-    mMaster->mDuration.Ref().isSome() || waitingForCDM;
+    mMaster->mDuration.Ref().isSome();
 
   if (mMaster->mNotifyMetadataBeforeFirstFrame) {
     mMaster->EnqueueLoadedMetadataEvent();
   }
 
-  if (waitingForCDM) {
-    // Metadata parsing was successful but we're still waiting for CDM caps
-    // to become available so that we can build the correct decryptor/decoder.
-    SetState<WaitForCDMState>();
-  } else {
-    SetState<DecodingFirstFrameState>(SeekJob{});
-  }
+  SetState<DecodingFirstFrameState>(SeekJob{});
 }
 
 void
@@ -1267,13 +1197,6 @@ DormantState::HandlePlayStateChanged(MediaDecoder::PlayState aPlayState)
   }
 }
 
-void
-MediaDecoderStateMachine::
-WaitForCDMState::HandleCDMProxyReady()
-{
-  SetState<DecodingFirstFrameState>(Move(mPendingSeek));
-}
-
 void
 MediaDecoderStateMachine::
 DecodingFirstFrameState::Enter(SeekJob aPendingSeek)
@@ -2249,7 +2172,6 @@ MediaDecoderStateMachine::ToStateStr(State aState)
 {
   switch (aState) {
     case DECODER_STATE_DECODING_METADATA:   return "DECODING_METADATA";
-    case DECODER_STATE_WAIT_FOR_CDM:        return "WAIT_FOR_CDM";
     case DECODER_STATE_DORMANT:             return "DORMANT";
     case DECODER_STATE_DECODING_FIRSTFRAME: return "DECODING_FIRSTFRAME";
     case DECODER_STATE_DECODING:            return "DECODING";
diff --git a/dom/media/MediaDecoderStateMachine.h b/dom/media/MediaDecoderStateMachine.h
index 6391c85740..ba9034e4fa 100644
--- a/dom/media/MediaDecoderStateMachine.h
+++ b/dom/media/MediaDecoderStateMachine.h
@@ -155,7 +155,6 @@ public:
   // Enumeration for the valid decoding states
   enum State {
     DECODER_STATE_DECODING_METADATA,
-    DECODER_STATE_WAIT_FOR_CDM,
     DECODER_STATE_DORMANT,
     DECODER_STATE_DECODING_FIRSTFRAME,
     DECODER_STATE_DECODING,
@@ -263,7 +262,6 @@ public:
 private:
   class StateObject;
   class DecodeMetadataState;
-  class WaitForCDMState;
   class DormantState;
   class DecodingFirstFrameState;
   class DecodingState;
-- 
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