From 2b4b6c5613d1d597c717990d3b0bb6b114e13caf Mon Sep 17 00:00:00 2001
From: Zaggy1024 <zaggy1024@gmail.com>
Date: Sat, 29 Oct 2022 19:53:24 -0500
Subject: [PATCH] LibVideo: Make VP9::Decoder a subclass of a new abstract
 VideoDecoder

This will allow other decoders to be used in place of VP9::Decoder when
new video decoders are implemented, such as AV1.
---
 Userland/Applications/VideoPlayer/main.cpp  |  6 ++---
 Userland/Libraries/LibVideo/VP9/Decoder.cpp |  5 ----
 Userland/Libraries/LibVideo/VP9/Decoder.h   |  9 +++----
 Userland/Libraries/LibVideo/VideoDecoder.h  | 26 +++++++++++++++++++++
 4 files changed, 34 insertions(+), 12 deletions(-)
 create mode 100644 Userland/Libraries/LibVideo/VideoDecoder.h

diff --git a/Userland/Applications/VideoPlayer/main.cpp b/Userland/Applications/VideoPlayer/main.cpp
index 03fecaa3d9..1c591a97d6 100644
--- a/Userland/Applications/VideoPlayer/main.cpp
+++ b/Userland/Applications/VideoPlayer/main.cpp
@@ -49,7 +49,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     main_widget->set_layout<GUI::VerticalBoxLayout>();
     auto image_widget = TRY(main_widget->try_add<GUI::ImageWidget>());
 
-    Video::VP9::Decoder vp9_decoder;
+    OwnPtr<Video::VideoDecoder> decoder = make<Video::VP9::Decoder>();
     size_t cluster_index = 0;
     size_t block_index = 0;
     size_t frame_index = 0;
@@ -76,14 +76,14 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
         if (!optional_sample.has_value())
             return;
 
-        auto result = vp9_decoder.receive_sample(optional_sample.release_value());
+        auto result = decoder->receive_sample(optional_sample.release_value());
 
         if (result.is_error()) {
             outln("Error decoding frame {}: {}", frame_number, result.error().string_literal());
             return;
         }
 
-        auto frame_result = vp9_decoder.get_decoded_frame();
+        auto frame_result = decoder->get_decoded_frame();
         if (frame_result.is_error()) {
             outln("Error retrieving frame {}: {}", frame_number, frame_result.error().string_literal());
             return;
diff --git a/Userland/Libraries/LibVideo/VP9/Decoder.cpp b/Userland/Libraries/LibVideo/VP9/Decoder.cpp
index b899d3e050..d03f9df5fd 100644
--- a/Userland/Libraries/LibVideo/VP9/Decoder.cpp
+++ b/Userland/Libraries/LibVideo/VP9/Decoder.cpp
@@ -42,11 +42,6 @@ DecoderErrorOr<void> Decoder::receive_sample(Span<u8 const> chunk_data)
     return {};
 }
 
-DecoderErrorOr<void> Decoder::receive_sample(ByteBuffer const& chunk_data)
-{
-    return receive_sample(chunk_data.span());
-}
-
 void Decoder::dump_frame_info()
 {
     m_parser->dump_info();
diff --git a/Userland/Libraries/LibVideo/VP9/Decoder.h b/Userland/Libraries/LibVideo/VP9/Decoder.h
index bde1dd671f..11e2671c36 100644
--- a/Userland/Libraries/LibVideo/VP9/Decoder.h
+++ b/Userland/Libraries/LibVideo/VP9/Decoder.h
@@ -13,23 +13,24 @@
 #include <AK/Span.h>
 #include <LibVideo/Color/CodingIndependentCodePoints.h>
 #include <LibVideo/DecoderError.h>
+#include <LibVideo/VideoDecoder.h>
 #include <LibVideo/VideoFrame.h>
 
 #include "Parser.h"
 
 namespace Video::VP9 {
 
-class Decoder {
+class Decoder : public VideoDecoder {
     friend class Parser;
 
 public:
     Decoder();
+    ~Decoder() override { }
     /* (8.1) General */
-    DecoderErrorOr<void> receive_sample(Span<u8 const>);
-    DecoderErrorOr<void> receive_sample(ByteBuffer const&);
+    DecoderErrorOr<void> receive_sample(Span<u8 const>) override;
     void dump_frame_info();
 
-    DecoderErrorOr<NonnullOwnPtr<VideoFrame>> get_decoded_frame();
+    DecoderErrorOr<NonnullOwnPtr<VideoFrame>> get_decoded_frame() override;
 
 private:
     typedef i32 Intermediate;
diff --git a/Userland/Libraries/LibVideo/VideoDecoder.h b/Userland/Libraries/LibVideo/VideoDecoder.h
new file mode 100644
index 0000000000..bcafc73fd5
--- /dev/null
+++ b/Userland/Libraries/LibVideo/VideoDecoder.h
@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2022, Gregory Bertilson <zaggy1024@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/ByteBuffer.h>
+#include <AK/NonnullOwnPtr.h>
+
+#include "DecoderError.h"
+#include "VideoFrame.h"
+
+namespace Video {
+
+class VideoDecoder {
+public:
+    virtual ~VideoDecoder() {};
+
+    virtual DecoderErrorOr<void> receive_sample(Span<u8 const> sample) = 0;
+    DecoderErrorOr<void> receive_sample(ByteBuffer const& sample) { return receive_sample(sample.span()); }
+    virtual DecoderErrorOr<NonnullOwnPtr<VideoFrame>> get_decoded_frame() = 0;
+};
+
+}