1 files changed, 149 insertions, 0 deletions
diff --git a/gfx/config/gfxVars.h b/gfx/config/gfxVars.h
new file mode 100644
index 000000000..2fd2689ed
--- /dev/null
+++ b/gfx/config/gfxVars.h
@@ -0,0 +1,149 @@
+/* -*- Mode: C++; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim: set sts=2 ts=8 sw=2 tw=99 et: */
+/* 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/. */
+#ifndef mozilla_gfx_config_gfxVars_h
+#define mozilla_gfx_config_gfxVars_h
+
+#include <stdint.h>
+#include "mozilla/Assertions.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/gfx/GraphicsMessages.h"
+#include "mozilla/gfx/Point.h"
+#include "mozilla/gfx/Types.h"
+#include "nsTArray.h"
+#include "nsXULAppAPI.h"
+
+namespace mozilla {
+namespace gfx {
+
+class gfxVarReceiver;
+
+// Generator for graphics vars.
+#define GFX_VARS_LIST(_)                                                \
+  /* C++ Name,                  Data Type,        Default Value */      \
+  _(BrowserTabsRemoteAutostart, bool,             false)                \
+  _(ContentBackend,             BackendType,      BackendType::NONE)    \
+  _(TileSize,                   IntSize,          IntSize(-1, -1))      \
+  _(UseXRender,                 bool,             false)                \
+  _(OffscreenFormat,            gfxImageFormat,   mozilla::gfx::SurfaceFormat::X8R8G8B8_UINT32) \
+  _(RequiresAcceleratedGLContextForCompositorOGL, bool, false)          \
+  _(CanUseHardwareVideoDecoding, bool,            false)                \
+  _(PDMWMFDisableD3D11Dlls,     nsCString,        nsCString())          \
+  _(PDMWMFDisableD3D9Dlls,      nsCString,        nsCString())          \
+
+  /* Add new entries above this line. */
+
+// Some graphics settings are computed on the UI process and must be
+// communicated to content and GPU processes. gfxVars helps facilitate
+// this. Its function is similar to gfxPrefs, except rather than hold
+// user preferences, it holds dynamically computed values.
+//
+// Each variable in GFX_VARS_LIST exposes the following static methods:
+//
+//    const DataType& CxxName();
+//    void SetCxxName(const DataType& aValue);
+//
+// Note that the setter may only be called in the UI process; a gfxVar must be
+// a variable that is determined in the UI process and pushed to child
+// processes.
+class gfxVars final
+{
+public:
+  static void Initialize();
+  static void Shutdown();
+
+  static void ApplyUpdate(const GfxVarUpdate& aUpdate);
+  static void AddReceiver(gfxVarReceiver* aReceiver);
+  static void RemoveReceiver(gfxVarReceiver* aReceiver);
+
+  // Return a list of updates for all variables with non-default values.
+  static nsTArray<GfxVarUpdate> FetchNonDefaultVars();
+
+public:
+  // Each variable must expose Set and Get methods for IPDL.
+  class VarBase
+  {
+  public:
+    VarBase();
+    virtual void SetValue(const GfxVarValue& aValue) = 0;
+    virtual void GetValue(GfxVarValue* aOutValue) = 0;
+    virtual bool HasDefaultValue() const = 0;
+    size_t Index() const {
+      return mIndex;
+    }
+  private:
+    size_t mIndex;
+  };
+
+private:
+  static StaticAutoPtr<gfxVars> sInstance;
+  static StaticAutoPtr<nsTArray<VarBase*>> sVarList;
+
+  template <typename T, T Default()>
+  class VarImpl final : public VarBase
+  {
+  public:
+    VarImpl()
+     : mValue(Default())
+    {}
+    void SetValue(const GfxVarValue& aValue) override {
+      aValue.get(&mValue);
+    }
+    void GetValue(GfxVarValue* aOutValue) override {
+      *aOutValue = GfxVarValue(mValue);
+    }
+    bool HasDefaultValue() const override {
+      return mValue == Default();
+    }
+    const T& Get() const {
+      return mValue;
+    }
+    // Return true if the value changed, false otherwise.
+    bool Set(const T& aValue) {
+      MOZ_ASSERT(XRE_IsParentProcess());
+      if (mValue == aValue) {
+        return false;
+      }
+      mValue = aValue;
+      return true;
+    }
+  private:
+    T mValue;
+  };
+
+#define GFX_VAR_DECL(CxxName, DataType, DefaultValue)           \
+private:                                                        \
+  static DataType Get##CxxName##Default() {                     \
+    return DefaultValue;                                        \
+  }                                                             \
+  VarImpl<DataType, Get##CxxName##Default> mVar##CxxName;       \
+public:                                                         \
+  static const DataType& CxxName() {                            \
+    return sInstance->mVar##CxxName.Get();                      \
+  }                                                             \
+  static void Set##CxxName(const DataType& aValue) {            \
+    if (sInstance->mVar##CxxName.Set(aValue)) {                 \
+      sInstance->NotifyReceivers(&sInstance->mVar##CxxName);    \
+    }                                                           \
+  }
+
+  GFX_VARS_LIST(GFX_VAR_DECL)
+#undef GFX_VAR_DECL
+
+private:
+  gfxVars();
+
+  void NotifyReceivers(VarBase* aVar);
+
+private:
+  nsTArray<gfxVarReceiver*> mReceivers;
+};
+
+#undef GFX_VARS_LIST
+
+} // namespace gfx
+} // namespace mozilla
+
+#endif // mozilla_gfx_config_gfxVars_h