1 files changed, 147 insertions, 0 deletions
diff --git a/gfx/gl/GLScreenBuffer.cpp b/gfx/gl/GLScreenBuffer.cpp
new file mode 100644
index 0000000000..9dda11b41a
--- /dev/null
+++ b/gfx/gl/GLScreenBuffer.cpp
@@ -0,0 +1,147 @@
+/* -*- Mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 4; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "GLScreenBuffer.h"
+
+#include "CompositorTypes.h"
+#include "GLContext.h"
+#include "gfx2DGlue.h"
+#include "MozFramebuffer.h"
+#include "SharedSurface.h"
+
+namespace mozilla::gl {
+
+// -
+// SwapChainPresenter
+
+// We need to apply pooling on Android because of the AndroidSurface slow
+// destructor bugs. They cause a noticeable performance hit. See bug
+// #1646073.
+static constexpr size_t kPoolSize =
+#if defined(MOZ_WIDGET_ANDROID)
+    4;
+#else
+    0;
+#endif
+
+UniquePtr<SwapChainPresenter> SwapChain::Acquire(
+    const gfx::IntSize& size, const gfx::ColorSpace2 colorSpace) {
+  MOZ_ASSERT(mFactory);
+
+  std::shared_ptr<SharedSurface> surf;
+  if (!mPool.empty()) {
+    // Try reuse
+    const auto& existingDesc = mPool.front()->mDesc;
+    auto newDesc = existingDesc;
+    newDesc.size = size;
+    newDesc.colorSpace = colorSpace;
+    if (newDesc != existingDesc || !mPool.front()->IsValid()) {
+      mPool = {};
+    }
+  }
+
+  // When mDestroyedCallback exists, recycling of SharedSurfaces is managed by
+  // the owner of the SwapChain by calling StoreRecycledSurface().
+  const auto poolSize = mDestroyedCallback ? 0 : kPoolSize;
+
+  if (!mPool.empty() && (!poolSize || mPool.size() == poolSize)) {
+    surf = mPool.front();
+    mPool.pop();
+  }
+  if (!surf) {
+    auto uniquePtrSurf = mFactory->CreateShared(size, colorSpace);
+    if (!uniquePtrSurf) return nullptr;
+    surf.reset(uniquePtrSurf.release());
+  }
+  mPool.push(surf);
+  while (mPool.size() > poolSize) {
+    mPool.pop();
+  }
+
+  auto ret = MakeUnique<SwapChainPresenter>(*this);
+  const auto old = ret->SwapBackBuffer(surf);
+  MOZ_ALWAYS_TRUE(!old);
+  return ret;
+}
+
+void SwapChain::ClearPool() {
+  mPool = {};
+  mPrevFrontBuffer = nullptr;
+}
+
+bool SwapChain::StoreRecycledSurface(
+    const std::shared_ptr<SharedSurface>& surf) {
+  MOZ_ASSERT(mFactory);
+  if (!mFactory || NS_WARN_IF(surf->mDesc.gl != mFactory->mDesc.gl)) {
+    // Ensure we don't accidentally store an expired shared surface or from a
+    // different context.
+    return false;
+  }
+  mPool.push(surf);
+  return true;
+}
+
+// -
+
+SwapChainPresenter::SwapChainPresenter(SwapChain& swapChain)
+    : mSwapChain(&swapChain) {
+  MOZ_RELEASE_ASSERT(mSwapChain->mPresenter == nullptr);
+  mSwapChain->mPresenter = this;
+}
+
+SwapChainPresenter::~SwapChainPresenter() {
+  if (!mSwapChain) return;
+  MOZ_RELEASE_ASSERT(mSwapChain->mPresenter == this);
+  mSwapChain->mPresenter = nullptr;
+
+  auto newFront = SwapBackBuffer(nullptr);
+  if (newFront) {
+    mSwapChain->mPrevFrontBuffer = mSwapChain->mFrontBuffer;
+    mSwapChain->mFrontBuffer = newFront;
+  }
+}
+
+std::shared_ptr<SharedSurface> SwapChainPresenter::SwapBackBuffer(
+    std::shared_ptr<SharedSurface> back) {
+  if (mBackBuffer) {
+    mBackBuffer->UnlockProd();
+    mBackBuffer->ProducerRelease();
+    mBackBuffer->Commit();
+  }
+  auto old = mBackBuffer;
+  mBackBuffer = back;
+  if (mBackBuffer) {
+    mBackBuffer->WaitForBufferOwnership();
+    mBackBuffer->ProducerAcquire();
+    mBackBuffer->LockProd();
+  }
+  return old;
+}
+
+GLuint SwapChainPresenter::Fb() const {
+  if (!mBackBuffer) return 0;
+  const auto& fb = mBackBuffer->mFb;
+  if (!fb) return 0;
+  return fb->mFB;
+}
+
+// -
+// SwapChain
+
+SwapChain::SwapChain() = default;
+
+SwapChain::~SwapChain() {
+  if (mPresenter) {
+    // Out of order destruction, but ok.
+    (void)mPresenter->SwapBackBuffer(nullptr);
+    mPresenter->mSwapChain = nullptr;
+    mPresenter = nullptr;
+  }
+  if (mDestroyedCallback) {
+    mDestroyedCallback();
+  }
+}
+
+}  // namespace mozilla::gl