tor-browser

The Tor Browser
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FxROutputHandler.cpp (3515B)

      1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* This Source Code Form is subject to the terms of the Mozilla Public
      3 * License, v. 2.0. If a copy of the MPL was not distributed with this
      4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      5 
      6 #include "FxROutputHandler.h"
      7 #include "mozilla/Assertions.h"
      8 #include "moz_external_vr.h"
      9 #include "VRShMem.h"
     10 
     11 // TryInitialize is responsible for associating this output handler with the
     12 // calling window's swapchain for subsequent updates. This also creates a
     13 // texture that can be shared across processes and updates VRShMem with the
     14 // shared texture handle.
     15 // See nsFxrCommandLineHandler::Handle for more information about the
     16 // bootstrap process.
     17 bool FxROutputHandler::TryInitialize(IDXGISwapChain* aSwapChain,
     18                                     ID3D11Device* aDevice) {
     19  if (mSwapChain == nullptr) {
     20    RefPtr<ID3D11Texture2D> texOrig = nullptr;
     21    HRESULT hr =
     22        aSwapChain->GetBuffer(0, IID_ID3D11Texture2D, getter_AddRefs(texOrig));
     23    if (hr != S_OK) {
     24      return false;
     25    }
     26 
     27    // Create shareable texture, which will be copied to
     28    D3D11_TEXTURE2D_DESC descOrig = {0};
     29    texOrig->GetDesc(&descOrig);
     30    descOrig.MiscFlags |=
     31        D3D11_RESOURCE_MISC_SHARED_NTHANDLE | D3D11_RESOURCE_MISC_SHARED;
     32    hr = aDevice->CreateTexture2D(&descOrig, nullptr,
     33                                  mTexCopy.StartAssignment());
     34    if (hr != S_OK) {
     35      return false;
     36    }
     37 
     38    // Now, share the texture to a handle that can be marshaled to another
     39    // process
     40    HANDLE hCopy = nullptr;
     41    RefPtr<IDXGIResource1> texResource;
     42    hr = mTexCopy->QueryInterface(IID_IDXGIResource1,
     43                                  getter_AddRefs(texResource));
     44    if (hr != S_OK) {
     45      return false;
     46    }
     47 
     48    hr = texResource->CreateSharedHandle(
     49        nullptr, DXGI_SHARED_RESOURCE_READ | DXGI_SHARED_RESOURCE_WRITE,
     50        nullptr, &hCopy);
     51    if (hr != S_OK) {
     52      return false;
     53    }
     54 
     55    // The texture is successfully created and shared, so cache a
     56    // pointer to the swapchain to indicate this success.
     57    mSwapChain = aSwapChain;
     58 
     59    // Finally, marshal the shared texture handle via VRShMem
     60    mozilla::gfx::VRShMem shmem(nullptr, true /*aRequiresMutex*/);
     61    if (shmem.JoinShMem()) {
     62      mozilla::gfx::VRWindowState windowState = {0};
     63      shmem.PullWindowState(windowState);
     64 
     65      // The CLH should have populated hwndFx first
     66      MOZ_ASSERT(windowState.hwndFx != 0);
     67      MOZ_ASSERT(windowState.textureFx == nullptr);
     68 
     69      windowState.textureFx = (HANDLE)hCopy;
     70 
     71      shmem.PushWindowState(windowState);
     72      shmem.LeaveShMem();
     73 
     74      // Notify the waiting host process that the data is now available
     75      HANDLE hSignal = ::OpenEventA(EVENT_ALL_ACCESS,       // dwDesiredAccess
     76                                    FALSE,                  // bInheritHandle
     77                                    windowState.signalName  // lpName
     78      );
     79      ::SetEvent(hSignal);
     80      ::CloseHandle(hSignal);
     81    }
     82  } else {
     83    MOZ_ASSERT(aSwapChain == mSwapChain);
     84  }
     85 
     86  return mSwapChain != nullptr && aSwapChain == mSwapChain;
     87 }
     88 
     89 // Update the contents of the shared texture.
     90 void FxROutputHandler::UpdateOutput(ID3D11DeviceContext* aCtx) {
     91  MOZ_ASSERT(mSwapChain != nullptr);
     92 
     93  ID3D11Texture2D* texOrig = nullptr;
     94  HRESULT hr = mSwapChain->GetBuffer(0, IID_PPV_ARGS(&texOrig));
     95  if (hr == S_OK) {
     96    aCtx->CopyResource(mTexCopy, texOrig);
     97    texOrig->Release();
     98  }
     99 }