The Tor Browser: layout/style/Declaration.h@925c144e1f1f (annotated)

layout/style/Declaration.h@925c144e1f1f (annotated)

layout/style/Declaration.h

Fri, 16 Jan 2015 18:13:44 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Fri, 16 Jan 2015 18:13:44 +0100
branch: TOR_BUG_9701
changeset 14: 925c144e1f1f
permissions: -rw-r--r--

Integrate suggestion from review to improve consistency with existing code.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* 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 (or style attribute) in a CSS
  * stylesheet
  */
 #ifndef mozilla_css_Declaration_h
 #define mozilla_css_Declaration_h
 // This header is in EXPORTS because it's used in several places in content/,
 // but it's not really a public interface.
 #ifndef MOZILLA_INTERNAL_API
 #error "This file should only be included within libxul"
 #endif
 #include "mozilla/Attributes.h"
 #include "mozilla/MemoryReporting.h"
 #include "CSSVariableDeclarations.h"
 #include "nsCSSDataBlock.h"
 #include "nsCSSProperty.h"
 #include "nsCSSProps.h"
 #include "nsStringFwd.h"
 #include "nsTArray.h"
 #include <stdio.h>
 namespace mozilla {
 namespace css {
 // Declaration objects have unusual lifetime rules.  Every declaration
 // begins life in an invalid state which ends when InitializeEmpty or
 // CompressFrom is called upon it.  After that, it can be attached to
 // exactly one style rule, and will be destroyed when that style rule
 // is destroyed.  A declaration becomes immutable when its style rule's
 // |RuleMatched| method is called; after that, it must be copied before
 // it can be modified, which is taken care of by |EnsureMutable|.
 class Declaration {
 public:
   /**
    * Construct an |Declaration| that is in an invalid state (null
    * |mData|) and cannot be used until its |CompressFrom| method or
    * |InitializeEmpty| method is called.
    */
   Declaration();
   Declaration(const Declaration& aCopy);
   ~Declaration();
   /**
    * |ValueAppended| must be called to maintain this declaration's
    * |mOrder| whenever a property is parsed into an expanded data block
    * for this declaration.  aProperty must not be a shorthand.
    */
   void ValueAppended(nsCSSProperty aProperty);
   void RemoveProperty(nsCSSProperty aProperty);
   bool HasProperty(nsCSSProperty aProperty) const;
   void GetValue(nsCSSProperty aProperty, nsAString& aValue) const;
   void GetAuthoredValue(nsCSSProperty aProperty, nsAString& aValue) const;
   bool HasImportantData() const {
     return mImportantData || mImportantVariables;
   }
   bool GetValueIsImportant(nsCSSProperty aProperty) const;
   bool GetValueIsImportant(const nsAString& aProperty) const;
   /**
    * Adds a custom property declaration to this object.
    *
    * @param aName The variable name (i.e., without the "--" prefix).
    * @param aType The type of value the variable has.
    * @param aValue The value of the variable, if aType is
    *   CSSVariableDeclarations::eTokenStream.
    * @param aIsImportant Whether the declaration is !important.
    * @param aOverrideImportant When aIsImportant is false, whether an
    *   existing !important declaration will be overridden.
    */
   void AddVariableDeclaration(const nsAString& aName,
                               CSSVariableDeclarations::Type aType,
                               const nsString& aValue,
                               bool aIsImportant,
                               bool aOverrideImportant);
   /**
    * Removes a custom property declaration from this object.
    *
    * @param aName The variable name (i.e., without the "--" prefix).
    */
   void RemoveVariableDeclaration(const nsAString& aName);
   /**
    * Returns whether a custom property declaration for a variable with
    * a given name exists on this object.
    *
    * @param aName The variable name (i.e., without the "--" prefix).
    */
   bool HasVariableDeclaration(const nsAString& aName) const;
   /**
    * Gets the string value for a custom property declaration of a variable
    * with a given name.
    *
    * @param aName The variable name (i.e., without the "--" prefix).
    * @param aValue Out parameter into which the variable's value will be
    *   stored.  If the value is 'initial' or 'inherit', that exact string
    *   will be stored in aValue.
    */
   void GetVariableDeclaration(const nsAString& aName, nsAString& aValue) const;
   /**
    * Returns whether the custom property declaration for a variable with
    * the given name was !important.
    */
   bool GetVariableValueIsImportant(const nsAString& aName) const;
   uint32_t Count() const {
     return mOrder.Length();
   }
   // Returns whether we actually had a property at aIndex
   bool GetNthProperty(uint32_t aIndex, nsAString& aReturn) const;
   void ToString(nsAString& aString) const;
   nsCSSCompressedDataBlock* GetNormalBlock() const { return mData; }
   nsCSSCompressedDataBlock* GetImportantBlock() const { return mImportantData; }
   /**
    * Initialize this declaration as holding no data.  Cannot fail.
    */
   void InitializeEmpty();
   /**
    * Transfer all of the state from |aExpandedData| into this declaration.
    * After calling, |aExpandedData| should be in its initial state.
    * Callers must make sure mOrder is updated as necessary.
    */
   void CompressFrom(nsCSSExpandedDataBlock *aExpandedData) {
     NS_ABORT_IF_FALSE(!mData, "oops");
     NS_ABORT_IF_FALSE(!mImportantData, "oops");
     aExpandedData->Compress(getter_Transfers(mData),
                             getter_Transfers(mImportantData));
     aExpandedData->AssertInitialState();
   }
   /**
    * Transfer all of the state from this declaration into
    * |aExpandedData| and put this declaration temporarily into an
    * invalid state (ended by |CompressFrom| or |InitializeEmpty|) that
    * should last only during parsing.  During this time only
    * |ValueAppended| should be called.
    */
   void ExpandTo(nsCSSExpandedDataBlock *aExpandedData) {
     AssertMutable();
     aExpandedData->AssertInitialState();
     NS_ABORT_IF_FALSE(mData, "oops");
     aExpandedData->Expand(mData.forget(), mImportantData.forget());
   }
   /**
    * Do what |nsIStyleRule::MapRuleInfoInto| needs to do for a style
    * rule using this declaration for storage.
    */
   void MapNormalRuleInfoInto(nsRuleData *aRuleData) const {
     NS_ABORT_IF_FALSE(mData, "called while expanded");
     mData->MapRuleInfoInto(aRuleData);
     if (mVariables) {
       mVariables->MapRuleInfoInto(aRuleData);
     }
   }
   void MapImportantRuleInfoInto(nsRuleData *aRuleData) const {
     NS_ABORT_IF_FALSE(mData, "called while expanded");
     NS_ABORT_IF_FALSE(mImportantData || mImportantVariables,
                       "must have important data or variables");
     if (mImportantData) {
       mImportantData->MapRuleInfoInto(aRuleData);
     }
     if (mImportantVariables) {
       mImportantVariables->MapRuleInfoInto(aRuleData);
     }
   }
   /**
    * Attempt to replace the value for |aProperty| stored in this
    * declaration with the matching value from |aFromBlock|.
    * This method may only be called on a mutable declaration.
    * It will fail (returning false) if |aProperty| is shorthand,
    * is not already in this declaration, or does not have the indicated
    * importance level.  If it returns true, it erases the value in
    * |aFromBlock|.  |aChanged| is set to true if the declaration
    * changed as a result of the call, and to false otherwise.
    */
   bool TryReplaceValue(nsCSSProperty aProperty, bool aIsImportant,
                          nsCSSExpandedDataBlock& aFromBlock,
                          bool* aChanged)
   {
     AssertMutable();
     NS_ABORT_IF_FALSE(mData, "called while expanded");
     if (nsCSSProps::IsShorthand(aProperty)) {
       *aChanged = false;
       return false;
     }
     nsCSSCompressedDataBlock *block = aIsImportant ? mImportantData : mData;
     // mImportantData might be null
     if (!block) {
       *aChanged = false;
       return false;
     }
 #ifdef DEBUG
     {
       nsCSSCompressedDataBlock *other = aIsImportant ? mData : mImportantData;
       NS_ABORT_IF_FALSE(!other || !other->ValueFor(aProperty) ||
                         !block->ValueFor(aProperty),
                         "Property both important and not?");
     }
 #endif
     return block->TryReplaceValue(aProperty, aFromBlock, aChanged);
   }
   bool HasNonImportantValueFor(nsCSSProperty aProperty) const {
     NS_ABORT_IF_FALSE(!nsCSSProps::IsShorthand(aProperty), "must be longhand");
     return !!mData->ValueFor(aProperty);
   }
   /**
    * Return whether |this| may be modified.
    */
   bool IsMutable() const {
     return !mImmutable;
   }
   /**
    * Copy |this|, if necessary to ensure that it can be modified.
    */
   Declaration* EnsureMutable();
   /**
    * Crash if |this| cannot be modified.
    */
   void AssertMutable() const {
     NS_ABORT_IF_FALSE(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; }
   /**
    * Clear the data, in preparation for its replacement with entirely
    * new data by a call to |CompressFrom|.
    */
   void ClearData() {
     AssertMutable();
     mData = nullptr;
     mImportantData = nullptr;
     mVariables = nullptr;
     mImportantVariables = nullptr;
     mOrder.Clear();
     mVariableOrder.Clear();
   }
 #ifdef DEBUG
   void List(FILE* out = stdout, int32_t aIndent = 0) const;
 #endif
 private:
   Declaration& operator=(const Declaration& aCopy) MOZ_DELETE;
   bool operator==(const Declaration& aCopy) const MOZ_DELETE;
   void GetValue(nsCSSProperty aProperty, nsAString& aValue,
                 nsCSSValue::Serialization aValueSerialization) const;
   static void AppendImportanceToString(bool aIsImportant, nsAString& aString);
   // return whether there was a value in |aValue| (i.e., it had a non-null unit)
   bool AppendValueToString(nsCSSProperty aProperty, nsAString& aResult) const;
   bool AppendValueToString(nsCSSProperty aProperty, nsAString& aResult,
                            nsCSSValue::Serialization aValueSerialization) const;
   // Helper for ToString with strange semantics regarding aValue.
   void AppendPropertyAndValueToString(nsCSSProperty aProperty,
                                       nsAutoString& aValue,
                                       nsAString& aResult) const;
   // helper for ToString that serializes a custom property declaration for
   // a variable with the specified name
   void AppendVariableAndValueToString(const nsAString& aName,
                                       nsAString& aResult) const;
 public:
   /**
    * Returns the property at the given index in the ordered list of
    * declarations.  For custom properties, eCSSPropertyExtra_variable
    * is returned.
    */
   nsCSSProperty GetPropertyAt(uint32_t aIndex) const {
     uint32_t value = mOrder[aIndex];
     if (value >= eCSSProperty_COUNT) {
       return eCSSPropertyExtra_variable;
     }
     return nsCSSProperty(value);
   }
   /**
    * Gets the name of the custom property at the given index in the ordered
    * list of declarations.
    */
   void GetCustomPropertyNameAt(uint32_t aIndex, nsAString& aResult) const {
     MOZ_ASSERT(mOrder[aIndex] >= eCSSProperty_COUNT);
     uint32_t variableIndex = mOrder[aIndex] - eCSSProperty_COUNT;
     aResult.Truncate();
     aResult.AppendLiteral("--");
     aResult.Append(mVariableOrder[variableIndex]);
   }
   size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
 private:
   // The order of properties in this declaration.  Longhand properties are
   // represented by their nsCSSProperty value, and each custom property (--*)
   // is represented by a value that begins at eCSSProperty_COUNT.
   //
   // Subtracting eCSSProperty_COUNT from those values that represent custom
   // properties results in an index into mVariableOrder, which identifies the
   // specific variable the custom property declaration is for.
   nsAutoTArray<uint32_t, 8> mOrder;
   // variable names of custom properties found in mOrder
   nsTArray<nsString> mVariableOrder;
   // never null, except while expanded, or before the first call to
   // InitializeEmpty or CompressFrom.
   nsAutoPtr<nsCSSCompressedDataBlock> mData;
   // may be null
   nsAutoPtr<nsCSSCompressedDataBlock> mImportantData;
   // may be null
   nsAutoPtr<CSSVariableDeclarations> mVariables;
   // may be null
   nsAutoPtr<CSSVariableDeclarations> mImportantVariables;
   // set by style rules when |RuleMatched| is called;
   // also by ToString (hence the 'mutable').
   mutable bool mImmutable;
 };
 } // namespace css
 } // namespace mozilla
 #endif /* mozilla_css_Declaration_h */

The Tor Browser / annotate

layout/style/Declaration.h@925c144e1f1f (annotated)

layout/style/Declaration.h