video_core: Rewrite the texture cache

The current texture cache has several points that hurt maintainability
and performance. It's easy to break unrelated parts of the cache
when doing minor changes. The cache can easily forget valuable
information about the cached textures by CPU writes or simply by its
normal usage.The current texture cache has several points that hurt
maintainability and performance. It's easy to break unrelated parts
of the cache when doing minor changes. The cache can easily forget
valuable information about the cached textures by CPU writes or simply
by its normal usage.

This commit aims to address those issues.

src/video_core/buffer_cache/buffer_cache.h

@@ -118,20 +118,17 @@ public:
     /// Prepares the buffer cache for data uploading
     /// @param max_size Maximum number of bytes that will be uploaded
     /// @return True when a stream buffer invalidation was required, false otherwise
-    bool Map(std::size_t max_size) {
+    void Map(std::size_t max_size) {
         std::lock_guard lock{mutex};
 
-        bool invalidated;
-        std::tie(buffer_ptr, buffer_offset_base, invalidated) = stream_buffer->Map(max_size, 4);
+        std::tie(buffer_ptr, buffer_offset_base) = stream_buffer.Map(max_size, 4);
         buffer_offset = buffer_offset_base;
-
-        return invalidated;
     }
 
     /// Finishes the upload stream
     void Unmap() {
         std::lock_guard lock{mutex};
-        stream_buffer->Unmap(buffer_offset - buffer_offset_base);
+        stream_buffer.Unmap(buffer_offset - buffer_offset_base);
     }
 
     /// Function called at the end of each frame, inteded for deferred operations
@@ -261,9 +258,9 @@ public:
 protected:
     explicit BufferCache(VideoCore::RasterizerInterface& rasterizer_,
                          Tegra::MemoryManager& gpu_memory_, Core::Memory::Memory& cpu_memory_,
-                         std::unique_ptr<StreamBuffer> stream_buffer_)
+                         StreamBuffer& stream_buffer_)
         : rasterizer{rasterizer_}, gpu_memory{gpu_memory_}, cpu_memory{cpu_memory_},
-          stream_buffer{std::move(stream_buffer_)}, stream_buffer_handle{stream_buffer->Handle()} {}
+          stream_buffer{stream_buffer_} {}
 
     ~BufferCache() = default;
 
@@ -441,7 +438,7 @@ private:
 
         buffer_ptr += size;
         buffer_offset += size;
-        return BufferInfo{stream_buffer->Handle(), uploaded_offset, stream_buffer->Address()};
+        return BufferInfo{stream_buffer.Handle(), uploaded_offset, stream_buffer.Address()};
     }
 
     void AlignBuffer(std::size_t alignment) {
@@ -567,9 +564,7 @@ private:
     VideoCore::RasterizerInterface& rasterizer;
     Tegra::MemoryManager& gpu_memory;
     Core::Memory::Memory& cpu_memory;
-
-    std::unique_ptr<StreamBuffer> stream_buffer;
-    BufferType stream_buffer_handle;
+    StreamBuffer& stream_buffer;
 
     u8* buffer_ptr = nullptr;
     u64 buffer_offset = 0;