1 files changed, 144 insertions, 0 deletions
diff --git a/gfx/config/gfxVars.cpp b/gfx/config/gfxVars.cpp
new file mode 100644
index 0000000000..9582f66268
--- /dev/null
+++ b/gfx/config/gfxVars.cpp
@@ -0,0 +1,144 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 "gfxVars.h"
+#include "gfxVarReceiver.h"
+#include "mozilla/dom/ContentChild.h"
+
+namespace mozilla {
+namespace gfx {
+
+StaticAutoPtr<gfxVars> gfxVars::sInstance;
+StaticAutoPtr<nsTArray<gfxVars::VarBase*>> gfxVars::sVarList;
+
+StaticAutoPtr<nsTArray<GfxVarUpdate>> gGfxVarInitUpdates;
+
+void gfxVars::SetValuesForInitialize(
+    const nsTArray<GfxVarUpdate>& aInitUpdates) {
+  // This should only be called once
+  MOZ_RELEASE_ASSERT(!gGfxVarInitUpdates);
+
+  // We expect aInitUpdates to be provided before any other gfxVars operation,
+  // and for sInstance to be null here, but handle the alternative.
+  if (sInstance) {
+    // Apply the updates, the object has been created already
+    for (const auto& varUpdate : aInitUpdates) {
+      ApplyUpdate(varUpdate);
+    }
+  } else {
+    // Save the values for Initialize call
+    gGfxVarInitUpdates = new nsTArray<GfxVarUpdate>(aInitUpdates.Clone());
+  }
+}
+
+void gfxVars::Initialize() {
+  if (sInstance) {
+    MOZ_RELEASE_ASSERT(
+        !gGfxVarInitUpdates,
+        "Initial updates should not be present after any gfxVars operation");
+    return;
+  }
+
+  // sVarList must be initialized first since it's used in the constructor for
+  // sInstance.
+  sVarList = new nsTArray<gfxVars::VarBase*>();
+  sInstance = new gfxVars;
+
+  // Content processes should have gotten a call to SetValuesForInitialize,
+  // which will have set gGfxVarInitUpdates.
+  MOZ_ASSERT_IF(XRE_IsContentProcess(), gGfxVarInitUpdates);
+
+  if (gGfxVarInitUpdates) {
+    // Apply any updates from gGfxVarInitUpdates.
+    for (const auto& varUpdate : *gGfxVarInitUpdates) {
+      ApplyUpdate(varUpdate);
+    }
+    gGfxVarInitUpdates = nullptr;
+  }
+}
+
+gfxVars::gfxVars() = default;
+
+void gfxVars::Shutdown() {
+  sInstance = nullptr;
+  sVarList = nullptr;
+  gGfxVarInitUpdates = nullptr;
+}
+
+/* static */
+void gfxVars::ApplyUpdate(const GfxVarUpdate& aUpdate) {
+  // Only subprocesses receive updates and apply them locally.
+  MOZ_ASSERT(!XRE_IsParentProcess());
+  MOZ_DIAGNOSTIC_ASSERT(sVarList || gGfxVarInitUpdates);
+  if (sVarList) {
+    sVarList->ElementAt(aUpdate.index())->SetValue(aUpdate.value());
+  } else if (gGfxVarInitUpdates) {
+    // Too early, we haven't been initialized, so just add to
+    // the array waiting for the initialization...
+    gGfxVarInitUpdates->AppendElement(aUpdate);
+  }
+}
+
+/* static */
+void gfxVars::AddReceiver(gfxVarReceiver* aReceiver) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // Don't double-add receivers, in case a broken content process sends two
+  // init messages.
+  if (!sInstance->mReceivers.Contains(aReceiver)) {
+    sInstance->mReceivers.AppendElement(aReceiver);
+  }
+}
+
+/* static */
+void gfxVars::RemoveReceiver(gfxVarReceiver* aReceiver) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (sInstance) {
+    sInstance->mReceivers.RemoveElement(aReceiver);
+  }
+}
+
+/* static */
+nsTArray<GfxVarUpdate> gfxVars::FetchNonDefaultVars() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(sVarList);
+
+  nsTArray<GfxVarUpdate> updates;
+  for (size_t i = 0; i < sVarList->Length(); i++) {
+    VarBase* var = sVarList->ElementAt(i);
+    if (var->HasDefaultValue()) {
+      continue;
+    }
+
+    GfxVarValue value;
+    var->GetValue(&value);
+
+    updates.AppendElement(GfxVarUpdate(i, value));
+  }
+
+  return updates;
+}
+
+gfxVars::VarBase::VarBase() {
+  mIndex = gfxVars::sVarList->Length();
+  gfxVars::sVarList->AppendElement(this);
+}
+
+void gfxVars::NotifyReceivers(VarBase* aVar) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  GfxVarValue value;
+  aVar->GetValue(&value);
+
+  GfxVarUpdate update(aVar->Index(), value);
+  for (auto& receiver : mReceivers) {
+    receiver->OnVarChanged(update);
+  }
+}
+
+}  // namespace gfx
+}  // namespace mozilla