Declaration.h
/* -*- 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 */
