| Index: mojo/public/dart/third_party/csslib/lib/src/polyfill.dart
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| diff --git a/mojo/public/dart/third_party/csslib/lib/src/polyfill.dart b/mojo/public/dart/third_party/csslib/lib/src/polyfill.dart
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| new file mode 100644
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| index 0000000000000000000000000000000000000000..9b682ce4cb127126f0589830647683cd481c3f65
|
| --- /dev/null
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| +++ b/mojo/public/dart/third_party/csslib/lib/src/polyfill.dart
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| @@ -0,0 +1,256 @@
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| +// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
|
| +// for details. All rights reserved. Use of this source code is governed by a
|
| +// BSD-style license that can be found in the LICENSE file.
|
| +
|
| +part of csslib.parser;
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| +
|
| +/**
|
| + * CSS polyfill emits CSS to be understood by older parsers that which do not
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| + * understand (var, calc, etc.).
|
| + */
|
| +class PolyFill {
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| + final Messages _messages;
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| + final bool _warningsAsErrors;
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| + Map<String, VarDefinition> _allVarDefinitions =
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| + new Map<String, VarDefinition>();
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| +
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| + Set<StyleSheet> allStyleSheets = new Set<StyleSheet>();
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| +
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| + /**
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| + * [_pseudoElements] list of known pseudo attributes found in HTML, any
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| + * CSS pseudo-elements 'name::custom-element' is mapped to the manged name
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| + * associated with the pseudo-element key.
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| + */
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| + PolyFill(this._messages, this._warningsAsErrors);
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| +
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| + /**
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| + * Run the analyzer on every file that is a style sheet or any component that
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| + * has a style tag.
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| + */
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| + void process(StyleSheet styleSheet, {List<StyleSheet> includes: null}) {
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| + if (includes != null) {
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| + processVarDefinitions(includes);
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| + }
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| + processVars(styleSheet);
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| +
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| + // Remove all var definitions for this style sheet.
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| + new _RemoveVarDefinitions().visitTree(styleSheet);
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| + }
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| +
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| + /** Process all includes looking for var definitions. */
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| + void processVarDefinitions(List<StyleSheet> includes) {
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| + for (var include in includes) {
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| + _allVarDefinitions = (new _VarDefinitionsIncludes(_allVarDefinitions)
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| + ..visitTree(include)).varDefs;
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| + }
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| + }
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| +
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| + void processVars(StyleSheet styleSheet) {
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| + // Build list of all var definitions.
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| + var mainStyleSheetVarDefs = (new _VarDefAndUsage(
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| + this._messages, _allVarDefinitions)..visitTree(styleSheet)).varDefs;
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| +
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| + // Resolve all definitions to a non-VarUsage (terminal expression).
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| + mainStyleSheetVarDefs.forEach((key, value) {
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| + for (var _ in (value.expression as Expressions).expressions) {
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| + mainStyleSheetVarDefs[key] =
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| + _findTerminalVarDefinition(_allVarDefinitions, value);
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| + }
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| + });
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| + }
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| +}
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| +
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| +/** Build list of all var definitions in all includes. */
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| +class _VarDefinitionsIncludes extends Visitor {
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| + final Map<String, VarDefinition> varDefs;
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| +
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| + _VarDefinitionsIncludes(this.varDefs);
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| +
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| + void visitTree(StyleSheet tree) {
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| + visitStyleSheet(tree);
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| + }
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| +
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| + visitVarDefinition(VarDefinition node) {
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| + // Replace with latest variable definition.
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| + varDefs[node.definedName] = node;
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| + super.visitVarDefinition(node);
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| + }
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| +
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| + void visitVarDefinitionDirective(VarDefinitionDirective node) {
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| + visitVarDefinition(node.def);
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| + }
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| +}
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| +
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| +/**
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| + * Find var- definitions in a style sheet.
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| + * [found] list of known definitions.
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| + */
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| +class _VarDefAndUsage extends Visitor {
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| + final Messages _messages;
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| + final Map<String, VarDefinition> _knownVarDefs;
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| + final Map<String, VarDefinition> varDefs = new Map<String, VarDefinition>();
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| +
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| + VarDefinition currVarDefinition;
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| + List<Expression> currentExpressions;
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| +
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| + _VarDefAndUsage(this._messages, this._knownVarDefs);
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| +
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| + void visitTree(StyleSheet tree) {
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| + visitStyleSheet(tree);
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| + }
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| +
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| + visitVarDefinition(VarDefinition node) {
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| + // Replace with latest variable definition.
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| + currVarDefinition = node;
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| +
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| + _knownVarDefs[node.definedName] = node;
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| + varDefs[node.definedName] = node;
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| +
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| + super.visitVarDefinition(node);
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| +
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| + currVarDefinition = null;
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| + }
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| +
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| + void visitVarDefinitionDirective(VarDefinitionDirective node) {
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| + visitVarDefinition(node.def);
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| + }
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| +
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| + void visitExpressions(Expressions node) {
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| + currentExpressions = node.expressions;
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| + super.visitExpressions(node);
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| + currentExpressions = null;
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| + }
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| +
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| + void visitVarUsage(VarUsage node) {
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| + if (currVarDefinition != null && currVarDefinition.badUsage) return;
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| +
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| + // Don't process other var() inside of a varUsage. That implies that the
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| + // default is a var() too. Also, don't process any var() inside of a
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| + // varDefinition (they're just place holders until we've resolved all real
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| + // usages.
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| + var expressions = currentExpressions;
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| + var index = expressions.indexOf(node);
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| + assert(index >= 0);
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| + var def = _knownVarDefs[node.name];
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| + if (def != null) {
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| + if (def.badUsage) {
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| + // Remove any expressions pointing to a bad var definition.
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| + expressions.removeAt(index);
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| + return;
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| + }
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| + _resolveVarUsage(currentExpressions, index,
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| + _findTerminalVarDefinition(_knownVarDefs, def));
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| + } else if (node.defaultValues.any((e) => e is VarUsage)) {
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| + // Don't have a VarDefinition need to use default values resolve all
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| + // default values.
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| + var terminalDefaults = <Expression>[];
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| + for (var defaultValue in node.defaultValues) {
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| + terminalDefaults.addAll(resolveUsageTerminal(defaultValue));
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| + }
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| + expressions.replaceRange(index, index + 1, terminalDefaults);
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| + } else if (node.defaultValues.isNotEmpty) {
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| + // No VarDefinition but default value is a terminal expression; use it.
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| + expressions.replaceRange(index, index + 1, node.defaultValues);
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| + } else {
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| + if (currVarDefinition != null) {
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| + currVarDefinition.badUsage = true;
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| + var mainStyleSheetDef = varDefs[node.name];
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| + if (mainStyleSheetDef != null) {
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| + varDefs.remove(currVarDefinition.property);
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| + }
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| + }
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| + // Remove var usage that points at an undefined definition.
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| + expressions.removeAt(index);
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| + _messages.warning("Variable is not defined.", node.span);
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| + }
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| +
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| + var oldExpressions = currentExpressions;
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| + currentExpressions = node.defaultValues;
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| + super.visitVarUsage(node);
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| + currentExpressions = oldExpressions;
|
| + }
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| +
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| + List<Expression> resolveUsageTerminal(VarUsage usage) {
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| + var result = [];
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| +
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| + var varDef = _knownVarDefs[usage.name];
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| + var expressions;
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| + if (varDef == null) {
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| + // VarDefinition not found try the defaultValues.
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| + expressions = usage.defaultValues;
|
| + } else {
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| + // Use the VarDefinition found.
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| + expressions = (varDef.expression as Expressions).expressions;
|
| + }
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| +
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| + for (var expr in expressions) {
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| + if (expr is VarUsage) {
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| + // Get terminal value.
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| + result.addAll(resolveUsageTerminal(expr));
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| + }
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| + }
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| +
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| + // We're at a terminal just return the VarDefinition expression.
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| + if (result.isEmpty && varDef != null) {
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| + result = (varDef.expression as Expressions).expressions;
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| + }
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| +
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| + return result;
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| + }
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| +
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| + _resolveVarUsage(List<Expression> expressions, int index, VarDefinition def) {
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| + var defExpressions = (def.expression as Expressions).expressions;
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| + expressions.replaceRange(index, index + 1, defExpressions);
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| + }
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| +}
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| +
|
| +/** Remove all var definitions. */
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| +class _RemoveVarDefinitions extends Visitor {
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| + void visitTree(StyleSheet tree) {
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| + visitStyleSheet(tree);
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| + }
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| +
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| + void visitStyleSheet(StyleSheet ss) {
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| + ss.topLevels.removeWhere((e) => e is VarDefinitionDirective);
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| + super.visitStyleSheet(ss);
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| + }
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| +
|
| + void visitDeclarationGroup(DeclarationGroup node) {
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| + node.declarations.removeWhere((e) => e is VarDefinition);
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| + super.visitDeclarationGroup(node);
|
| + }
|
| +}
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| +
|
| +/** Find terminal definition (non VarUsage implies real CSS value). */
|
| +VarDefinition _findTerminalVarDefinition(
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| + Map<String, VarDefinition> varDefs, VarDefinition varDef) {
|
| + var expressions = varDef.expression as Expressions;
|
| + for (var expr in expressions.expressions) {
|
| + if (expr is VarUsage) {
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| + var usageName = (expr as VarUsage).name;
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| + var foundDef = varDefs[usageName];
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| +
|
| + // If foundDef is unknown check if defaultValues; if it exist then resolve
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| + // to terminal value.
|
| + if (foundDef == null) {
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| + // We're either a VarUsage or terminal definition if in varDefs;
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| + // either way replace VarUsage with it's default value because the
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| + // VarDefinition isn't found.
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| + var defaultValues = (expr as VarUsage).defaultValues;
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| + var replaceExprs = expressions.expressions;
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| + assert(replaceExprs.length == 1);
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| + replaceExprs.replaceRange(0, 1, defaultValues);
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| + return varDef;
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| + }
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| + if (foundDef is VarDefinition) {
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| + return _findTerminalVarDefinition(varDefs, foundDef);
|
| + }
|
| + } else {
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| + // Return real CSS property.
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| + return varDef;
|
| + }
|
| + }
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| +
|
| + // Didn't point to a var definition that existed.
|
| + return varDef;
|
| +}
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|
|