148 lines
4.4 KiB
C++
148 lines
4.4 KiB
C++
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* object that resolves CSS variables using specified and inherited variable
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* values
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*/
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#ifndef mozilla_CSSVariableResolver_h
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#define mozilla_CSSVariableResolver_h
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#include "mozilla/DebugOnly.h"
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#include "nsCSSParser.h"
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#include "nsCSSScanner.h"
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#include "nsDataHashtable.h"
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#include "nsTArray.h"
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namespace mozilla {
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class CSSVariableDeclarations;
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class CSSVariableValues;
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class EnumerateVariableReferencesData;
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class CSSVariableResolver
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{
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friend class CSSVariableDeclarations;
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friend class CSSVariableValues;
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friend class EnumerateVariableReferencesData;
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public:
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/**
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* Creates a new CSSVariableResolver that will output a set of resolved,
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* computed variables into aOutput.
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*/
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explicit CSSVariableResolver(CSSVariableValues* aOutput)
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: mOutput(aOutput)
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#ifdef DEBUG
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, mResolved(false)
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#endif
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{
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MOZ_ASSERT(aOutput);
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}
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/**
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* Resolves the set of inherited variables from aInherited and the
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* set of specified variables from aSpecified. The resolved variables
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* are written into mOutput.
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*/
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void Resolve(const CSSVariableValues* aInherited,
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const CSSVariableDeclarations* aSpecified);
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private:
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struct Variable
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{
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Variable(const nsAString& aVariableName,
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nsString aValue,
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nsCSSTokenSerializationType aFirstToken,
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nsCSSTokenSerializationType aLastToken,
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bool aWasInherited)
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: mVariableName(aVariableName)
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, mValue(aValue)
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, mFirstToken(aFirstToken)
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, mLastToken(aLastToken)
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, mWasInherited(aWasInherited)
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, mResolved(false)
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, mReferencesNonExistentVariable(false)
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, mInStack(false)
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, mIndex(0)
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, mLowLink(0) { }
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nsString mVariableName;
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nsString mValue;
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nsCSSTokenSerializationType mFirstToken;
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nsCSSTokenSerializationType mLastToken;
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// Whether this variable came from the set of inherited variables.
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bool mWasInherited;
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// Whether this variable has been resolved yet.
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bool mResolved;
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// Whether this variables includes any references to non-existent variables.
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bool mReferencesNonExistentVariable;
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// Bookkeeping for the cycle remover algorithm.
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bool mInStack;
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size_t mIndex;
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size_t mLowLink;
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};
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/**
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* Adds or modifies an existing entry in the set of variables to be resolved.
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* This is intended to be called by the AddVariablesToResolver functions on
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* the CSSVariableDeclarations and CSSVariableValues objects passed in to
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* Resolve.
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*
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* @param aName The variable name (not including any "--" prefix that would
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* be part of the custom property name) whose value is to be set.
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* @param aValue The variable value.
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* @param aFirstToken The type of token at the start of the variable value.
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* @param aLastToken The type of token at the en of the variable value.
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* @param aWasInherited Whether this variable came from the set of inherited
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* variables.
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*/
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void Put(const nsAString& aVariableName,
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nsString aValue,
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nsCSSTokenSerializationType aFirstToken,
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nsCSSTokenSerializationType aLastToken,
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bool aWasInherited);
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// Helper functions for Resolve.
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void RemoveCycles(size_t aID);
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void ResolveVariable(size_t aID);
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// A mapping of variable names to an ID that indexes into mVariables
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// and mReferences.
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nsDataHashtable<nsStringHashKey, size_t> mVariableIDs;
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// The set of variables.
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nsTArray<Variable> mVariables;
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// The list of variables that each variable references.
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nsTArray<nsTArray<size_t> > mReferences;
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// The next index to assign to a variable found during the cycle removing
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// algorithm's traversal of the variable reference graph.
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size_t mNextIndex;
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// Stack of variable IDs that we push to as we traverse the variable reference
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// graph while looking for cycles. Variable::mInStack reflects whether a
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// given variable has its ID in mStack.
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nsTArray<size_t> mStack;
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// CSS parser to use for parsing property values with variable references.
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nsCSSParser mParser;
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// The object to output the resolved variables into.
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CSSVariableValues* mOutput;
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#ifdef DEBUG
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// Whether Resolve has been called.
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bool mResolved;
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#endif
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};
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} // namespace mozilla
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#endif
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