1 files changed, 265 insertions, 0 deletions
diff --git a/widget/RemoteLookAndFeel.cpp b/widget/RemoteLookAndFeel.cpp
new file mode 100644
index 0000000000..8ca87d9631
--- /dev/null
+++ b/widget/RemoteLookAndFeel.cpp
@@ -0,0 +1,265 @@
+/* -*- 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/Result.h"
+#include "mozilla/ResultExtensions.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "nsLookAndFeel.h"
+#include "nsXULAppAPI.h"
+
+#include <limits>
+#include <type_traits>
+#include <utility>
+
+namespace mozilla::widget {
+
+RemoteLookAndFeel::RemoteLookAndFeel(FullLookAndFeel&& aData)
+    : mTables(std::move(aData.tables())) {
+  MOZ_ASSERT(XRE_IsContentProcess(),
+             "Only content processes should be using a RemoteLookAndFeel");
+
+#ifdef MOZ_WIDGET_GTK
+  if (!StaticPrefs::widget_disable_native_theme_for_content()) {
+    // Configure the theme in this content process with the Gtk theme that was
+    // chosen by WithThemeConfiguredForContent in the parent process.
+    nsLookAndFeel::ConfigureTheme(aData.theme());
+  }
+#endif
+}
+
+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());
+
+#ifdef MOZ_WIDGET_GTK
+  if (!StaticPrefs::widget_disable_native_theme_for_content()) {
+    // Configure the theme in this content process with the Gtk theme that was
+    // chosen by WithThemeConfiguredForContent in the parent process.
+    nsLookAndFeel::ConfigureTheme(aData.theme());
+  }
+#endif
+}
+
+namespace {
+
+template <typename Item, typename UInt, typename ID>
+Result<const Item*, nsresult> MapLookup(const nsTArray<Item>& aItems,
+                                        const nsTArray<UInt>& aMap, ID aID,
+                                        ID aMinimum = ID(0)) {
+  UInt mapped = aMap[static_cast<size_t>(aID) - static_cast<size_t>(aMinimum)];
+
+  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>
+void AddToMap(nsTArray<Item>* aItems, nsTArray<UInt>* aMap,
+              Maybe<Item>&& aNewItem) {
+  if (aNewItem.isNothing()) {
+    aMap->AppendElement(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->AppendElement(static_cast<UInt>(i));
+      return;
+    }
+  }
+
+  aItems->AppendElement(aNewItem.extract());
+  aMap->AppendElement(static_cast<UInt>(newIndex));
+}
+
+}  // namespace
+
+nsresult RemoteLookAndFeel::NativeGetColor(ColorID aID, nscolor& aResult) {
+  const nscolor* result;
+  MOZ_TRY_VAR(result, MapLookup(mTables.colors(), mTables.colorMap(), aID));
+  aResult = *result;
+  return NS_OK;
+}
+
+nsresult RemoteLookAndFeel::NativeGetInt(IntID aID, int32_t& aResult) {
+  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, FontID::MINIMUM);
+  if (result.isErr()) {
+    return false;
+  }
+
+  const LookAndFeelFont& font = *result.unwrap();
+  MOZ_ASSERT(font.haveFont());
+  aFontName = font.name();
+  aFontStyle = gfxFontStyle();
+  aFontStyle.size = font.size();
+  aFontStyle.weight = FontWeight(font.weight());
+  aFontStyle.style =
+      font.italic() ? FontSlantStyle::Italic() : FontSlantStyle::Normal();
+
+  return true;
+}
+
+char16_t RemoteLookAndFeel::GetPasswordCharacterImpl() {
+  return static_cast<char16_t>(mTables.passwordChar());
+}
+
+bool RemoteLookAndFeel::GetEchoPasswordImpl() { return mTables.passwordEcho(); }
+
+// 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();
+
+  int32_t darkTheme = 0;
+  int32_t accessibilityTheme = 0;
+  impl->NativeGetInt(IntID::SystemUsesDarkTheme, darkTheme);
+  impl->NativeGetInt(IntID::UseAccessibilityTheme, accessibilityTheme);
+
+  impl->WithThemeConfiguredForContent([&](const LookAndFeelTheme& aTheme) {
+    for (auto id : MakeEnumeratedRange(IntID::End)) {
+      int32_t theInt;
+      nsresult rv;
+      // We want to take SystemUsesDarkTheme and UseAccessibilityTheme from
+      // the parent process theme rather than the content configured theme.
+      // This ensures that media queries like (prefers-color-scheme: dark) will
+      // match correctly in content processes.
+      //
+      // (When the RemoteLookAndFeel is not in use, the LookAndFeelCache
+      // ensures we get these values from the parent process theme.)
+      switch (id) {
+        case IntID::SystemUsesDarkTheme:
+          theInt = darkTheme;
+          rv = NS_OK;
+          break;
+        case IntID::UseAccessibilityTheme:
+          theInt = accessibilityTheme;
+          rv = NS_OK;
+          break;
+        default:
+          rv = impl->NativeGetInt(id, theInt);
+          break;
+      }
+      AddToMap(&lf->tables().ints(), &lf->tables().intMap(),
+               NS_SUCCEEDED(rv) ? Some(theInt) : Nothing{});
+    }
+
+    for (auto id : MakeEnumeratedRange(FloatID::End)) {
+      float theFloat;
+      nsresult rv = impl->NativeGetFloat(id, theFloat);
+      AddToMap(&lf->tables().floats(), &lf->tables().floatMap(),
+               NS_SUCCEEDED(rv) ? Some(theFloat) : Nothing{});
+    }
+
+    for (auto id : MakeEnumeratedRange(ColorID::End)) {
+      nscolor theColor;
+      nsresult rv = impl->NativeGetColor(id, theColor);
+      AddToMap(&lf->tables().colors(), &lf->tables().colorMap(),
+               NS_SUCCEEDED(rv) ? Some(theColor) : Nothing{});
+    }
+
+    for (auto id :
+         MakeInclusiveEnumeratedRange(FontID::MINIMUM, FontID::MAXIMUM)) {
+      LookAndFeelFont font{};
+      gfxFontStyle fontStyle{};
+
+      bool rv = impl->NativeGetFont(id, font.name(), fontStyle);
+      Maybe<LookAndFeelFont> maybeFont;
+      if (rv) {
+        font.haveFont() = true;
+        font.size() = fontStyle.size;
+        font.weight() = fontStyle.weight.ToFloat();
+        font.italic() = fontStyle.style.IsItalic();
+        MOZ_ASSERT(fontStyle.style.IsNormal() || fontStyle.style.IsItalic(),
+                   "Cannot handle oblique font style");
+#ifdef DEBUG
+        {
+          // Assert that all the remaining font style properties have their
+          // default values.
+          gfxFontStyle candidate = fontStyle;
+          gfxFontStyle defaults{};
+          candidate.size = defaults.size;
+          candidate.weight = defaults.weight;
+          candidate.style = defaults.style;
+          MOZ_ASSERT(candidate.Equals(defaults),
+                     "Some font style properties not supported");
+        }
+#endif
+        maybeFont = Some(std::move(font));
+      }
+      AddToMap(&lf->tables().fonts(), &lf->tables().fontMap(),
+               std::move(maybeFont));
+    }
+
+    lf->tables().passwordChar() = impl->GetPasswordCharacterImpl();
+    lf->tables().passwordEcho() = impl->GetEchoPasswordImpl();
+#ifdef MOZ_WIDGET_GTK
+    lf->theme() = aTheme;
+#endif
+  });
+
+  // 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;
+}
+
+StaticAutoPtr<FullLookAndFeel> RemoteLookAndFeel::sCachedLookAndFeelData;
+
+}  // namespace mozilla::widget