Add m-esr52 at 52.6.0

1 files changed, 82 insertions, 0 deletions

diff --git a/layout/style/ServoUtils.h b/layout/style/ServoUtils.h
new file mode 100644
index 0000000000..b116b9c4f4
--- /dev/null
+++ b/layout/style/ServoUtils.h
@@ -0,0 +1,82 @@
+/* -*- 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/. */
+
+/* some utilities for stylo */
+
+#ifndef mozilla_ServoUtils_h
+#define mozilla_ServoUtils_h
+
+#include "mozilla/TypeTraits.h"
+
+#ifdef MOZ_STYLO
+# define MOZ_DECL_STYLO_CHECK_METHODS \
+  bool IsGecko() const { return !IsServo(); } \
+  bool IsServo() const { return mType == StyleBackendType::Servo; }
+#else
+# define MOZ_DECL_STYLO_CHECK_METHODS \
+  bool IsGecko() const { return true; } \
+  bool IsServo() const { return false; }
+#endif
+
+/**
+ * Macro used in a base class of |geckotype_| and |servotype_|.
+ * The class should define |StyleBackendType mType;| itself.
+ */
+#define MOZ_DECL_STYLO_METHODS(geckotype_, servotype_)  \
+  MOZ_DECL_STYLO_CHECK_METHODS                          \
+  inline geckotype_* AsGecko();                         \
+  inline servotype_* AsServo();                         \
+  inline const geckotype_* AsGecko() const;             \
+  inline const servotype_* AsServo() const;
+
+/**
+ * Macro used in inline header of class |type_| with its Gecko and Servo
+ * subclasses named |geckotype_| and |servotype_| correspondingly for
+ * implementing the inline methods defined by MOZ_DECL_STYLO_METHODS.
+ */
+#define MOZ_DEFINE_STYLO_METHODS(type_, geckotype_, servotype_) \
+  geckotype_* type_::AsGecko() {                                \
+    MOZ_ASSERT(IsGecko());                                      \
+    return static_cast<geckotype_*>(this);                      \
+  }                                                             \
+  servotype_* type_::AsServo() {                                \
+    MOZ_ASSERT(IsServo());                                      \
+    return static_cast<servotype_*>(this);                      \
+  }                                                             \
+  const geckotype_* type_::AsGecko() const {                    \
+    MOZ_ASSERT(IsGecko());                                      \
+    return static_cast<const geckotype_*>(this);                \
+  }                                                             \
+  const servotype_* type_::AsServo() const {                    \
+    MOZ_ASSERT(IsServo());                                      \
+    return static_cast<const servotype_*>(this);                \
+  }
+
+#define MOZ_STYLO_THIS_TYPE  mozilla::RemovePointer<decltype(this)>::Type
+#define MOZ_STYLO_GECKO_TYPE mozilla::RemovePointer<decltype(AsGecko())>::Type
+#define MOZ_STYLO_SERVO_TYPE mozilla::RemovePointer<decltype(AsServo())>::Type
+
+/**
+ * Macro used to forward a method call to the concrete method defined by
+ * the Servo or Gecko implementation. The class of the method using it
+ * should use MOZ_DECL_STYLO_METHODS to define basic stylo methods.
+ */
+#define MOZ_STYLO_FORWARD_CONCRETE(method_, geckoargs_, servoargs_)         \
+  static_assert(!mozilla::IsSame<decltype(&MOZ_STYLO_THIS_TYPE::method_),   \
+                                 decltype(&MOZ_STYLO_GECKO_TYPE::method_)>  \
+                ::value, "Gecko subclass should define its own " #method_); \
+  static_assert(!mozilla::IsSame<decltype(&MOZ_STYLO_THIS_TYPE::method_),   \
+                                 decltype(&MOZ_STYLO_SERVO_TYPE::method_)>  \
+                ::value, "Servo subclass should define its own " #method_); \
+  if (IsServo()) {                                                          \
+    return AsServo()->method_ servoargs_;                                   \
+  }                                                                         \
+  return AsGecko()->method_ geckoargs_;
+
+#define MOZ_STYLO_FORWARD(method_, args_) \
+  MOZ_STYLO_FORWARD_CONCRETE(method_, args_, args_)
+
+#endif // mozilla_ServoUtils_h