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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
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parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
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+/* vim: set shiftwidth=2 tabstop=8 autoindent cindent expandtab: */
+/* 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/. */
+
+/* object that resolves CSS variables using specified and inherited variable
+ * values
+ */
+
+#ifndef mozilla_CSSVariableResolver_h
+#define mozilla_CSSVariableResolver_h
+
+#include "mozilla/DebugOnly.h"
+#include "nsCSSParser.h"
+#include "nsCSSScanner.h"
+#include "nsDataHashtable.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+
+class CSSVariableDeclarations;
+class CSSVariableValues;
+class EnumerateVariableReferencesData;
+
+class CSSVariableResolver
+{
+ friend class CSSVariableDeclarations;
+ friend class CSSVariableValues;
+ friend class EnumerateVariableReferencesData;
+public:
+ /**
+ * Creates a new CSSVariableResolver that will output a set of resolved,
+ * computed variables into aOutput.
+ */
+ explicit CSSVariableResolver(CSSVariableValues* aOutput)
+ : mOutput(aOutput)
+#ifdef DEBUG
+ , mResolved(false)
+#endif
+ {
+ MOZ_ASSERT(aOutput);
+ }
+
+ /**
+ * Resolves the set of inherited variables from aInherited and the
+ * set of specified variables from aSpecified. The resolved variables
+ * are written into mOutput.
+ */
+ void Resolve(const CSSVariableValues* aInherited,
+ const CSSVariableDeclarations* aSpecified);
+
+private:
+ struct Variable
+ {
+ Variable(const nsAString& aVariableName,
+ nsString aValue,
+ nsCSSTokenSerializationType aFirstToken,
+ nsCSSTokenSerializationType aLastToken,
+ bool aWasInherited)
+ : mVariableName(aVariableName)
+ , mValue(aValue)
+ , mFirstToken(aFirstToken)
+ , mLastToken(aLastToken)
+ , mWasInherited(aWasInherited)
+ , mResolved(false)
+ , mReferencesNonExistentVariable(false)
+ , mInStack(false)
+ , mIndex(0)
+ , mLowLink(0) { }
+
+ nsString mVariableName;
+ nsString mValue;
+ nsCSSTokenSerializationType mFirstToken;
+ nsCSSTokenSerializationType mLastToken;
+
+ // Whether this variable came from the set of inherited variables.
+ bool mWasInherited;
+
+ // Whether this variable has been resolved yet.
+ bool mResolved;
+
+ // Whether this variables includes any references to non-existent variables.
+ bool mReferencesNonExistentVariable;
+
+ // Bookkeeping for the cycle remover algorithm.
+ bool mInStack;
+ size_t mIndex;
+ size_t mLowLink;
+ };
+
+ /**
+ * Adds or modifies an existing entry in the set of variables to be resolved.
+ * This is intended to be called by the AddVariablesToResolver functions on
+ * the CSSVariableDeclarations and CSSVariableValues objects passed in to
+ * Resolve.
+ *
+ * @param aName The variable name (not including any "--" prefix that would
+ * be part of the custom property name) whose value is to be set.
+ * @param aValue The variable value.
+ * @param aFirstToken The type of token at the start of the variable value.
+ * @param aLastToken The type of token at the en of the variable value.
+ * @param aWasInherited Whether this variable came from the set of inherited
+ * variables.
+ */
+ void Put(const nsAString& aVariableName,
+ nsString aValue,
+ nsCSSTokenSerializationType aFirstToken,
+ nsCSSTokenSerializationType aLastToken,
+ bool aWasInherited);
+
+ // Helper functions for Resolve.
+ void RemoveCycles(size_t aID);
+ void ResolveVariable(size_t aID);
+
+ // A mapping of variable names to an ID that indexes into mVariables
+ // and mReferences.
+ nsDataHashtable<nsStringHashKey, size_t> mVariableIDs;
+
+ // The set of variables.
+ nsTArray<Variable> mVariables;
+
+ // The list of variables that each variable references.
+ nsTArray<nsTArray<size_t> > mReferences;
+
+ // The next index to assign to a variable found during the cycle removing
+ // algorithm's traversal of the variable reference graph.
+ size_t mNextIndex;
+
+ // Stack of variable IDs that we push to as we traverse the variable reference
+ // graph while looking for cycles. Variable::mInStack reflects whether a
+ // given variable has its ID in mStack.
+ nsTArray<size_t> mStack;
+
+ // CSS parser to use for parsing property values with variable references.
+ nsCSSParser mParser;
+
+ // The object to output the resolved variables into.
+ CSSVariableValues* mOutput;
+
+#ifdef DEBUG
+ // Whether Resolve has been called.
+ bool mResolved;
+#endif
+};
+
+} // namespace mozilla
+
+#endif