From 580c75e9e0565957e8c6868bad2ab3cb087740c8 Mon Sep 17 00:00:00 2001
From: Nicolas Silva <nsilva@mozilla.com>
Date: Mon, 28 Jul 2014 14:58:38 +0200
Subject: [PATCH] Bug 1043929 - Ensure that a locked TextureHost can give
 access to a valid TextureSource for some of the texture types. r=Bas

---
 gfx/layers/composite/TextureHost.cpp | 17 +++++++++++------
 gfx/layers/d3d11/TextureD3D11.cpp    |  3 +++
 gfx/layers/d3d9/TextureD3D9.cpp      | 14 +++++++++++---
 3 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/gfx/layers/composite/TextureHost.cpp b/gfx/layers/composite/TextureHost.cpp
index d5006f87a29..ed22f1fa7da 100644
--- a/gfx/layers/composite/TextureHost.cpp
+++ b/gfx/layers/composite/TextureHost.cpp
@@ -397,23 +397,26 @@ BufferTextureHost::DeallocateDeviceData()
 bool
 BufferTextureHost::Lock()
 {
-  mLocked = true;
-  return true;
+  MOZ_ASSERT(!mLocked);
+  if (!MaybeUpload(mPartialUpdate ? &mMaybeUpdatedRegion : nullptr)) {
+      return false;
+  }
+  mLocked = !!mFirstSource;
+  return mLocked;
 }
 
 void
 BufferTextureHost::Unlock()
 {
+  MOZ_ASSERT(mLocked);
   mLocked = false;
 }
 
 NewTextureSource*
 BufferTextureHost::GetTextureSources()
 {
-  MOZ_ASSERT(mLocked, "should never be called while not locked");
-  if (!MaybeUpload(mPartialUpdate ? &mMaybeUpdatedRegion : nullptr)) {
-      return nullptr;
-  }
+  MOZ_ASSERT(mLocked);
+  MOZ_ASSERT(mFirstSource);
   return mFirstSource;
 }
 
@@ -442,6 +445,7 @@ BufferTextureHost::MaybeUpload(nsIntRegion *aRegion)
   if (!Upload(aRegion)) {
     return false;
   }
+  // If upload returns true we know mFirstSource is not null
   mFirstSource->SetUpdateSerial(mUpdateSerial);
   return true;
 }
@@ -546,6 +550,7 @@ BufferTextureHost::Upload(nsIntRegion *aRegion)
       return false;
     }
   }
+  MOZ_ASSERT(mFirstSource);
   return true;
 }
 
diff --git a/gfx/layers/d3d11/TextureD3D11.cpp b/gfx/layers/d3d11/TextureD3D11.cpp
index 8e4f91977ef..db3bddd0f91 100644
--- a/gfx/layers/d3d11/TextureD3D11.cpp
+++ b/gfx/layers/d3d11/TextureD3D11.cpp
@@ -394,6 +394,9 @@ DXGITextureHostD3D11::Unlock()
 NewTextureSource*
 DXGITextureHostD3D11::GetTextureSources()
 {
+  MOZ_ASSERT(mIsLocked);
+  // If Lock was successful we must have a valid TextureSource.
+  MOZ_ASSERT(mTextureSource);
   return mTextureSource.get();
 }
 
diff --git a/gfx/layers/d3d9/TextureD3D9.cpp b/gfx/layers/d3d9/TextureD3D9.cpp
index 185ec87a997..f11e0dc045b 100644
--- a/gfx/layers/d3d9/TextureD3D9.cpp
+++ b/gfx/layers/d3d9/TextureD3D9.cpp
@@ -763,6 +763,7 @@ TextureHostD3D9::TextureHostD3D9(TextureFlags aFlags,
   , mIsLocked(false)
 {
   mTexture = reinterpret_cast<IDirect3DTexture9*>(aDescriptor.texture());
+  MOZ_ASSERT(mTexture);
   mTexture->Release(); // see AddRef in CairoTextureClientD3D9::ToSurfaceDescriptor
   MOZ_ASSERT(mTexture);
   D3DSURFACE_DESC desc;
@@ -848,6 +849,7 @@ DataTextureSourceD3D9::UpdateFromTexture(IDirect3DTexture9* aTexture,
 void
 TextureHostD3D9::Updated(const nsIntRegion* aRegion)
 {
+  MOZ_ASSERT(mTexture);
   if (!mTexture) {
     return;
   }
@@ -879,6 +881,7 @@ NewTextureSource*
 TextureHostD3D9::GetTextureSources()
 {
   MOZ_ASSERT(mIsLocked);
+  MOZ_ASSERT(mTextureSource);
   return mTextureSource;
 }
 
@@ -886,8 +889,11 @@ bool
 TextureHostD3D9::Lock()
 {
   MOZ_ASSERT(!mIsLocked);
-  mIsLocked = true;
-  return true;
+  // XXX - Currently if a TextureHostD3D9 is created but Update is never called,
+  // it will not have a TextureSource although it could since it has a valid
+  // D3D9 texture.
+  mIsLocked = !!mTextureSource;
+  return mIsLocked;
 }
 
 void
@@ -917,12 +923,15 @@ DXGITextureHostD3D9::DXGITextureHostD3D9(TextureFlags aFlags,
 NewTextureSource*
 DXGITextureHostD3D9::GetTextureSources()
 {
+  MOZ_ASSERT(mIsLocked);
+  MOZ_ASSERT(mTextureSource);
   return mTextureSource;
 }
 
 bool
 DXGITextureHostD3D9::Lock()
 {
+  MOZ_ASSERT(!mIsLocked);
   DeviceManagerD3D9* deviceManager = gfxWindowsPlatform::GetPlatform()->GetD3D9DeviceManager();
   if (!deviceManager) {
     NS_WARNING("trying to lock a TextureHost without a D3D device");
@@ -947,7 +956,6 @@ DXGITextureHostD3D9::Lock()
     mTextureSource = new DataTextureSourceD3D9(mFormat, mSize, mCompositor, tex);
   }
 
-  MOZ_ASSERT(!mIsLocked);
   mIsLocked = true;
   return true;
 }