1 files changed, 236 insertions, 0 deletions
diff --git a/widget/RemoteLookAndFeel.cpp b/widget/RemoteLookAndFeel.cpp
new file mode 100644
index 0000000000..5eea54496b
--- /dev/null
+++ b/widget/RemoteLookAndFeel.cpp
@@ -0,0 +1,236 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 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/. */
+
+#include "RemoteLookAndFeel.h"
+
+#include "gfxFont.h"
+#include "MainThreadUtils.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/ResultExtensions.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/Try.h"
+#include "nsXULAppAPI.h"
+
+#include <limits>
+#include <type_traits>
+#include <utility>
+
+namespace mozilla::widget {
+
+// A cached copy of the data extracted by ExtractData.
+//
+// Storing this lets us avoid doing most of the work of ExtractData each
+// time we create a new content process.
+//
+// Only used in the parent process.
+static StaticAutoPtr<FullLookAndFeel> sCachedLookAndFeelData;
+
+RemoteLookAndFeel::RemoteLookAndFeel(FullLookAndFeel&& aData)
+    : mTables(std::move(aData.tables())) {
+  MOZ_ASSERT(XRE_IsContentProcess(),
+             "Only content processes should be using a RemoteLookAndFeel");
+}
+
+RemoteLookAndFeel::~RemoteLookAndFeel() = default;
+
+void RemoteLookAndFeel::SetDataImpl(FullLookAndFeel&& aData) {
+  MOZ_ASSERT(XRE_IsContentProcess(),
+             "Only content processes should be using a RemoteLookAndFeel");
+  MOZ_ASSERT(NS_IsMainThread());
+  mTables = std::move(aData.tables());
+}
+
+namespace {
+
+// Some lnf values are somewhat expensive to get, and are not needed in child
+// processes, so we can avoid querying them.
+bool IsNeededInChildProcess(LookAndFeel::IntID aId) {
+  switch (aId) {
+    case LookAndFeel::IntID::AlertNotificationOrigin:
+      return false;  // see bug 1703205
+    default:
+      return true;
+  }
+}
+
+template <typename Item, typename UInt, typename ID>
+Result<const Item*, nsresult> MapLookup(const nsTArray<Item>& aItems,
+                                        const nsTArray<UInt>& aMap, ID aID) {
+  UInt mapped = aMap[static_cast<size_t>(aID)];
+
+  if (mapped == std::numeric_limits<UInt>::max()) {
+    return Err(NS_ERROR_NOT_IMPLEMENTED);
+  }
+
+  return &aItems[static_cast<size_t>(mapped)];
+}
+
+template <typename Item, typename UInt, typename Id>
+void AddToMap(nsTArray<Item>& aItems, nsTArray<UInt>& aMap, Id aId,
+              Maybe<Item>&& aNewItem) {
+  auto mapIndex = size_t(aId);
+  aMap.EnsureLengthAtLeast(mapIndex + 1);
+  if (aNewItem.isNothing()) {
+    aMap[mapIndex] = std::numeric_limits<UInt>::max();
+    return;
+  }
+
+  size_t newIndex = aItems.Length();
+  MOZ_ASSERT(newIndex < std::numeric_limits<UInt>::max());
+
+  // Check if there is an existing value in aItems that we can point to.
+  //
+  // The arrays should be small enough and contain few enough unique
+  // values that sequential search here is reasonable.
+  for (size_t i = 0; i < newIndex; ++i) {
+    if (aItems[i] == aNewItem.ref()) {
+      aMap[mapIndex] = static_cast<UInt>(i);
+      return;
+    }
+  }
+
+  aItems.AppendElement(aNewItem.extract());
+  aMap[mapIndex] = static_cast<UInt>(newIndex);
+}
+
+}  // namespace
+
+nsresult RemoteLookAndFeel::NativeGetColor(ColorID aID, ColorScheme aScheme,
+                                           nscolor& aResult) {
+  const nscolor* result;
+  const bool dark = aScheme == ColorScheme::Dark;
+  MOZ_TRY_VAR(
+      result,
+      MapLookup(dark ? mTables.darkColors() : mTables.lightColors(),
+                dark ? mTables.darkColorMap() : mTables.lightColorMap(), aID));
+  aResult = *result;
+  return NS_OK;
+}
+
+nsresult RemoteLookAndFeel::NativeGetInt(IntID aID, int32_t& aResult) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      IsNeededInChildProcess(aID),
+      "Querying value that we didn't bother getting from the parent process!");
+
+  const int32_t* result;
+  MOZ_TRY_VAR(result, MapLookup(mTables.ints(), mTables.intMap(), aID));
+  aResult = *result;
+  return NS_OK;
+}
+
+nsresult RemoteLookAndFeel::NativeGetFloat(FloatID aID, float& aResult) {
+  const float* result;
+  MOZ_TRY_VAR(result, MapLookup(mTables.floats(), mTables.floatMap(), aID));
+  aResult = *result;
+  return NS_OK;
+}
+
+bool RemoteLookAndFeel::NativeGetFont(FontID aID, nsString& aFontName,
+                                      gfxFontStyle& aFontStyle) {
+  auto result = MapLookup(mTables.fonts(), mTables.fontMap(), aID);
+  if (result.isErr()) {
+    return false;
+  }
+  const LookAndFeelFont& font = *result.unwrap();
+  return LookAndFeelFontToStyle(font, aFontName, aFontStyle);
+}
+
+char16_t RemoteLookAndFeel::GetPasswordCharacterImpl() {
+  return static_cast<char16_t>(mTables.passwordChar());
+}
+
+bool RemoteLookAndFeel::GetEchoPasswordImpl() { return mTables.passwordEcho(); }
+
+static bool AddIDsToMap(nsXPLookAndFeel* aImpl, FullLookAndFeel* aLf) {
+  using IntID = LookAndFeel::IntID;
+  using FontID = LookAndFeel::FontID;
+  using FloatID = LookAndFeel::FloatID;
+  using ColorID = LookAndFeel::ColorID;
+  using ColorScheme = LookAndFeel::ColorScheme;
+
+  bool anyFromOtherTheme = false;
+  for (auto id : MakeEnumeratedRange(IntID::End)) {
+    if (!IsNeededInChildProcess(id)) {
+      continue;
+    }
+    int32_t theInt;
+    nsresult rv = aImpl->NativeGetInt(id, theInt);
+    AddToMap(aLf->tables().ints(), aLf->tables().intMap(), id,
+             NS_SUCCEEDED(rv) ? Some(theInt) : Nothing{});
+  }
+
+  for (auto id : MakeEnumeratedRange(ColorID::End)) {
+    nscolor theColor;
+    nsresult rv = aImpl->NativeGetColor(id, ColorScheme::Light, theColor);
+    AddToMap(aLf->tables().lightColors(), aLf->tables().lightColorMap(), id,
+             NS_SUCCEEDED(rv) ? Some(theColor) : Nothing{});
+    rv = aImpl->NativeGetColor(id, ColorScheme::Dark, theColor);
+    AddToMap(aLf->tables().darkColors(), aLf->tables().darkColorMap(), id,
+             NS_SUCCEEDED(rv) ? Some(theColor) : Nothing{});
+  }
+
+  for (auto id : MakeEnumeratedRange(FloatID::End)) {
+    float theFloat;
+    nsresult rv = aImpl->NativeGetFloat(id, theFloat);
+    AddToMap(aLf->tables().floats(), aLf->tables().floatMap(), id,
+             NS_SUCCEEDED(rv) ? Some(theFloat) : Nothing{});
+  }
+
+  for (auto id : MakeEnumeratedRange(FontID::End)) {
+    gfxFontStyle fontStyle{};
+
+    nsString name;
+    bool rv = aImpl->NativeGetFont(id, name, fontStyle);
+    Maybe<LookAndFeelFont> maybeFont;
+    if (rv) {
+      maybeFont.emplace(
+          nsXPLookAndFeel::StyleToLookAndFeelFont(name, fontStyle));
+    }
+    AddToMap(aLf->tables().fonts(), aLf->tables().fontMap(), id,
+             std::move(maybeFont));
+  }
+
+  return anyFromOtherTheme;
+}
+
+// static
+const FullLookAndFeel* RemoteLookAndFeel::ExtractData() {
+  MOZ_ASSERT(XRE_IsParentProcess(),
+             "Only parent processes should be extracting LookAndFeel data");
+
+  if (sCachedLookAndFeelData) {
+    return sCachedLookAndFeelData;
+  }
+
+  static bool sInitialized = false;
+  if (!sInitialized) {
+    sInitialized = true;
+    ClearOnShutdown(&sCachedLookAndFeelData);
+  }
+
+  FullLookAndFeel* lf = new FullLookAndFeel{};
+  nsXPLookAndFeel* impl = nsXPLookAndFeel::GetInstance();
+
+  lf->tables().passwordChar() = impl->GetPasswordCharacterImpl();
+  lf->tables().passwordEcho() = impl->GetEchoPasswordImpl();
+
+  AddIDsToMap(impl, lf);
+
+  // This assignment to sCachedLookAndFeelData must be done after the
+  // WithThemeConfiguredForContent call, since it can end up calling RefreshImpl
+  // on the LookAndFeel, which will clear out sCachedTables.
+  sCachedLookAndFeelData = lf;
+  return sCachedLookAndFeelData;
+}
+
+void RemoteLookAndFeel::ClearCachedData() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  sCachedLookAndFeelData = nullptr;
+}
+
+}  // namespace mozilla::widget