From 0e796b1dcd0b311685fb81936ab5a5bb14d45ab1 Mon Sep 17 00:00:00 2001
From: trav90 <travawine@palemoon.org>
Date: Wed, 20 Sep 2023 13:49:59 -0500
Subject: [PATCH] Issue #2311 - Part 3 - Add accessor for ffvpx real DFT
 functions

---
 dom/media/platforms/ffmpeg/FFmpegRDFTTypes.h    |  7 +++++++
 .../ffmpeg/ffvpx/FFVPXRuntimeLinker.cpp         | 17 +++++++++++++++++
 .../platforms/ffmpeg/ffvpx/FFVPXRuntimeLinker.h |  8 ++++++++
 dom/media/platforms/moz.build                   |  3 +++
 4 files changed, 35 insertions(+)

diff --git a/dom/media/platforms/ffmpeg/FFmpegRDFTTypes.h b/dom/media/platforms/ffmpeg/FFmpegRDFTTypes.h
index 679d12ceba..b34aa08221 100644
--- a/dom/media/platforms/ffmpeg/FFmpegRDFTTypes.h
+++ b/dom/media/platforms/ffmpeg/FFmpegRDFTTypes.h
@@ -24,4 +24,11 @@ extern "C" {
 
 }
 
+struct FFmpegRDFTFuncs
+{
+    AvRdftInitFn init;
+    AvRdftCalcFn calc;
+    AvRdftEndFn end;
+};
+
 #endif // FFmpegRDFTTypes_h
diff --git a/dom/media/platforms/ffmpeg/ffvpx/FFVPXRuntimeLinker.cpp b/dom/media/platforms/ffmpeg/ffvpx/FFVPXRuntimeLinker.cpp
index ba39c178e7..514d9505eb 100644
--- a/dom/media/platforms/ffmpeg/ffvpx/FFVPXRuntimeLinker.cpp
+++ b/dom/media/platforms/ffmpeg/ffvpx/FFVPXRuntimeLinker.cpp
@@ -48,6 +48,7 @@ FFVPXRuntimeLinker::Init()
     return sLinkStatus == LinkStatus_SUCCEEDED;
   }
 
+  MOZ_ASSERT(NS_IsMainThread());
   sLinkStatus = LinkStatus_FAILED;
 
   // We retrieve the path of the lgpllibs library as this is where mozavcodec
@@ -109,4 +110,20 @@ FFVPXRuntimeLinker::CreateDecoderModule()
   return FFmpegDecoderModule<FFVPX_VERSION>::Create(&sFFVPXLib);
 }
 
+/* static */ void
+FFVPXRuntimeLinker::GetRDFTFuncs(FFmpegRDFTFuncs* aOutFuncs)
+{
+  MOZ_ASSERT(sLinkStatus != LinkStatus_INIT);
+  if (sFFVPXLib.av_rdft_init &&
+      sFFVPXLib.av_rdft_calc &&
+      sFFVPXLib.av_rdft_end) {
+    aOutFuncs->init = sFFVPXLib.av_rdft_init;
+    aOutFuncs->calc = sFFVPXLib.av_rdft_calc;
+    aOutFuncs->end = sFFVPXLib.av_rdft_end;
+  } else {
+    NS_WARNING("RDFT functions expected but not found");
+    *aOutFuncs = FFmpegRDFTFuncs(); // zero
+  }
+}
+
 } // namespace mozilla
diff --git a/dom/media/platforms/ffmpeg/ffvpx/FFVPXRuntimeLinker.h b/dom/media/platforms/ffmpeg/ffvpx/FFVPXRuntimeLinker.h
index e0633441fb..8d4d8f96cb 100644
--- a/dom/media/platforms/ffmpeg/ffvpx/FFVPXRuntimeLinker.h
+++ b/dom/media/platforms/ffmpeg/ffvpx/FFVPXRuntimeLinker.h
@@ -8,16 +8,24 @@
 
 #include "PlatformDecoderModule.h"
 
+struct FFmpegRDFTFuncs;
+
 namespace mozilla
 {
 
 class FFVPXRuntimeLinker
 {
 public:
+  // Main thread only.
   static bool Init();
+  // Main thread or after Init().
   static already_AddRefed<PlatformDecoderModule> CreateDecoderModule();
 
+  // Call (on any thread) after Init().
+  static void GetRDFTFuncs(FFmpegRDFTFuncs* aOutFuncs);
+
 private:
+  // Set once on the main thread and then read from other threads.
   static enum LinkStatus {
     LinkStatus_INIT = 0,
     LinkStatus_FAILED,
diff --git a/dom/media/platforms/moz.build b/dom/media/platforms/moz.build
index 8e89f88554..09d9afa4d2 100644
--- a/dom/media/platforms/moz.build
+++ b/dom/media/platforms/moz.build
@@ -43,6 +43,9 @@ if CONFIG['MOZ_WMF']:
 
 if CONFIG['MOZ_FFVPX'] or CONFIG['MOZ_FFMPEG']:
     # common code to either FFmpeg or FFVPX
+    EXPORTS += [
+        'ffmpeg/FFmpegRDFTTypes.h',
+    ]
     UNIFIED_SOURCES += [
         'ffmpeg/FFmpegLibWrapper.cpp',
     ]