1 files changed, 146 insertions, 0 deletions
diff --git a/layout/style/DeclarationBlock.h b/layout/style/DeclarationBlock.h
new file mode 100644
index 000000000..c3ed663b4
--- /dev/null
+++ b/layout/style/DeclarationBlock.h
@@ -0,0 +1,146 @@
+/* -*- 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/. */
+
+/*
+ * representation of a declaration block in a CSS stylesheet, or of
+ * a style attribute
+ */
+
+#ifndef mozilla_DeclarationBlock_h
+#define mozilla_DeclarationBlock_h
+
+#include "mozilla/ServoUtils.h"
+#include "mozilla/StyleBackendType.h"
+
+#include "nsCSSPropertyID.h"
+
+class nsHTMLCSSStyleSheet;
+
+namespace mozilla {
+
+class ServoDeclarationBlock;
+
+namespace css {
+class Declaration;
+class Rule;
+} // namespace css
+
+class DeclarationBlock
+{
+protected:
+  explicit DeclarationBlock(StyleBackendType aType)
+    : mImmutable(false), mType(aType) { mContainer.mRaw = 0; }
+
+  DeclarationBlock(const DeclarationBlock& aCopy)
+    : DeclarationBlock(aCopy.mType) {}
+
+public:
+  MOZ_DECL_STYLO_METHODS(css::Declaration, ServoDeclarationBlock)
+
+  inline MozExternalRefCountType AddRef();
+  inline MozExternalRefCountType Release();
+
+  inline already_AddRefed<DeclarationBlock> Clone() const;
+
+  /**
+   * Return whether |this| may be modified.
+   */
+  bool IsMutable() const {
+    return !mImmutable;
+  }
+
+  /**
+   * Crash if |this| cannot be modified.
+   */
+  void AssertMutable() const {
+    MOZ_ASSERT(IsMutable(), "someone forgot to call EnsureMutable");
+  }
+
+  /**
+   * Mark this declaration as unmodifiable.  It's 'const' so it can
+   * be called from ToString.
+   */
+  void SetImmutable() const { mImmutable = true; }
+
+  /**
+   * Copy |this|, if necessary to ensure that it can be modified.
+   */
+  inline already_AddRefed<DeclarationBlock> EnsureMutable();
+
+  void SetOwningRule(css::Rule* aRule) {
+    MOZ_ASSERT(!mContainer.mOwningRule || !aRule,
+               "should never overwrite one rule with another");
+    mContainer.mOwningRule = aRule;
+  }
+
+  css::Rule* GetOwningRule() const {
+    if (mContainer.mRaw & 0x1) {
+      return nullptr;
+    }
+    return mContainer.mOwningRule;
+  }
+
+  void SetHTMLCSSStyleSheet(nsHTMLCSSStyleSheet* aHTMLCSSStyleSheet) {
+    MOZ_ASSERT(!mContainer.mHTMLCSSStyleSheet || !aHTMLCSSStyleSheet,
+               "should never overwrite one sheet with another");
+    mContainer.mHTMLCSSStyleSheet = aHTMLCSSStyleSheet;
+    if (aHTMLCSSStyleSheet) {
+      mContainer.mRaw |= uintptr_t(1);
+    }
+  }
+
+  nsHTMLCSSStyleSheet* GetHTMLCSSStyleSheet() const {
+    if (!(mContainer.mRaw & 0x1)) {
+      return nullptr;
+    }
+    auto c = mContainer;
+    c.mRaw &= ~uintptr_t(1);
+    return c.mHTMLCSSStyleSheet;
+  }
+
+  inline void ToString(nsAString& aString) const;
+
+  inline uint32_t Count() const;
+  inline bool GetNthProperty(uint32_t aIndex, nsAString& aReturn) const;
+
+  inline void GetPropertyValue(const nsAString& aProperty,
+                               nsAString& aValue) const;
+  inline void GetPropertyValueByID(nsCSSPropertyID aPropID,
+                                   nsAString& aValue) const;
+  inline void GetAuthoredPropertyValue(const nsAString& aProperty,
+                                       nsAString& aValue) const;
+  inline bool GetPropertyIsImportant(const nsAString& aProperty) const;
+  inline void RemoveProperty(const nsAString& aProperty);
+  inline void RemovePropertyByID(nsCSSPropertyID aProperty);
+
+private:
+  union {
+    // We only ever have one of these since we have an
+    // nsHTMLCSSStyleSheet only for style attributes, and style
+    // attributes never have an owning rule.
+
+    // It's an nsHTMLCSSStyleSheet if the low bit is set.
+
+    uintptr_t mRaw;
+
+    // The style rule that owns this declaration.  May be null.
+    css::Rule* mOwningRule;
+
+    // The nsHTMLCSSStyleSheet that is responsible for this declaration.
+    // Only non-null for style attributes.
+    nsHTMLCSSStyleSheet* mHTMLCSSStyleSheet;
+  } mContainer;
+
+  // set when declaration put in the rule tree;
+  // also by ToString (hence the 'mutable').
+  mutable bool mImmutable;
+
+  const StyleBackendType mType;
+};
+
+} // namespace mozilla
+
+#endif // mozilla_DeclarationBlock_h