move polymer.dart into dart svn

pkg/polymer/lib/src/css_analyzer.dart

+// 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.
+
+/** Portion of the analyzer dealing with CSS sources. */
+library polymer.src.css_analyzer;
+
+import 'package:csslib/parser.dart' as css;
+import 'package:csslib/visitor.dart';
+import 'package:html5lib/dom.dart';
+import 'package:html5lib/dom_parsing.dart';
+
+import 'info.dart';
+import 'files.dart' show SourceFile;
+import 'messages.dart';
+import 'compiler_options.dart';
+
+void analyzeCss(String packageRoot, List<SourceFile> files,
+                Map<String, FileInfo> info, Map<String, String> pseudoElements,
+                Messages messages, {warningsAsErrors: false}) {
+  var analyzer = new _AnalyzerCss(packageRoot, info, pseudoElements, messages,
+      warningsAsErrors);
+  for (var file in files) analyzer.process(file);
+  analyzer.normalize();
+}
+
+class _AnalyzerCss {
+  final String packageRoot;
+  final Map<String, FileInfo> info;
+  final Map<String, String> _pseudoElements;
+  final Messages _messages;
+  final bool _warningsAsErrors;
+
+  Set<StyleSheet> allStyleSheets = new Set<StyleSheet>();
+
+  /**
+   * [_pseudoElements] list of known pseudo attributes found in HTML, any
+   * CSS pseudo-elements 'name::custom-element' is mapped to the manged name
+   * associated with the pseudo-element key.
+   */
+  _AnalyzerCss(this.packageRoot, this.info, this._pseudoElements,
+               this._messages, this._warningsAsErrors);
+
+  /**
+   * Run the analyzer on every file that is a style sheet or any component that
+   * has a style tag.
+   */
+  void process(SourceFile file) {
+    var fileInfo = info[file.path];
+    if (file.isStyleSheet || fileInfo.styleSheets.length > 0) {
+      var styleSheets = processVars(fileInfo);
+
+      // Add to list of all style sheets analyzed.
+      allStyleSheets.addAll(styleSheets);
+    }
+
+    // Process any components.
+    for (var component in fileInfo.declaredComponents) {
+      var all = processVars(component);
+
+      // Add to list of all style sheets analyzed.
+      allStyleSheets.addAll(all);
+    }
+
+    processCustomPseudoElements();
+  }
+
+  void normalize() {
+    // Remove all var definitions for all style sheets analyzed.
+    for (var tree in allStyleSheets) new _RemoveVarDefinitions().visitTree(tree);
+  }
+
+  List<StyleSheet> processVars(var libraryInfo) {
+    // Get list of all stylesheet(s) dependencies referenced from this file.
+    var styleSheets = _dependencies(libraryInfo).toList();
+
+    var errors = [];
+    css.analyze(styleSheets, errors: errors, options:
+      [_warningsAsErrors ? '--warnings_as_errors' : '', 'memory']);
+
+    // Print errors as warnings.
+    for (var e in errors) {
+      _messages.warning(e.message, e.span);
+    }
+
+    // Build list of all var definitions.
+    Map varDefs = new Map();
+    for (var tree in styleSheets) {
+      var allDefs = (new _VarDefinitions()..visitTree(tree)).found;
+      allDefs.forEach((key, value) {
+        varDefs[key] = value;
+      });
+    }
+
+    // Resolve all definitions to a non-VarUsage (terminal expression).
+    varDefs.forEach((key, value) {
+      for (var expr in (value.expression as Expressions).expressions) {
+        var def = _findTerminalVarDefinition(varDefs, value);
+        varDefs[key] = def;
+      }
+    });
+
+    // Resolve all var usages.
+    for (var tree in styleSheets) new _ResolveVarUsages(varDefs).visitTree(tree);
+
+    return styleSheets;
+  }
+
+  processCustomPseudoElements() {
+    var polyFiller = new _PseudoElementExpander(_pseudoElements);
+    for (var tree in allStyleSheets) {
+      polyFiller.visitTree(tree);
+    }
+  }
+
+  /**
+   * Given a component or file check if any stylesheets referenced.  If so then
+   * return a list of all referenced stylesheet dependencies (@imports or <link
+   * rel="stylesheet" ..>).
+   */
+  Set<StyleSheet> _dependencies(var libraryInfo, {Set<StyleSheet> seen}) {
+    if (seen == null) seen = new Set();
+
+    // Used to resolve all pathing information.
+    var inputUrl = libraryInfo is FileInfo
+        ? libraryInfo.inputUrl
+        : (libraryInfo as ComponentInfo).declaringFile.inputUrl;
+
+    for (var styleSheet in libraryInfo.styleSheets) {
+      if (!seen.contains(styleSheet)) {
+        // TODO(terry): VM uses expandos to implement hashes.  Currently, it's a
+        //              linear (not constant) time cost (see dartbug.com/5746).
+        //              If this bug isn't fixed and performance show's this a
+        //              a problem we'll need to implement our own hashCode or
+        //              use a different key for better perf.
+        // Add the stylesheet.
+        seen.add(styleSheet);
+
+        // Any other imports in this stylesheet?
+        var urlInfos = findImportsInStyleSheet(styleSheet, packageRoot,
+            inputUrl, _messages);
+
+        // Process other imports in this stylesheets.
+        for (var importSS in urlInfos) {
+          var importInfo = info[importSS.resolvedPath];
+          if (importInfo != null) {
+            // Add all known stylesheets processed.
+            seen.addAll(importInfo.styleSheets);
+            // Find dependencies for stylesheet referenced with a
+            // @import
+            for (var ss in importInfo.styleSheets) {
+              var urls = findImportsInStyleSheet(ss, packageRoot, inputUrl,
+                  _messages);
+              for (var url in urls) {
+                _dependencies(info[url.resolvedPath], seen: seen);
+              }
+            }
+          }
+        }
+      }
+    }
+
+    return seen;
+  }
+}
+
+/**
+ * Find var- definitions in a style sheet.
+ * [found] list of known definitions.
+ */
+class _VarDefinitions extends Visitor {
+  final Map<String, VarDefinition> found = new Map();
+
+  void visitTree(StyleSheet tree) {
+    visitStyleSheet(tree);
+  }
+
+  visitVarDefinition(VarDefinition node) {
+    // Replace with latest variable definition.
+    found[node.definedName] = node;
+    super.visitVarDefinition(node);
+  }
+
+  void visitVarDefinitionDirective(VarDefinitionDirective node) {
+    visitVarDefinition(node.def);
+  }
+}
+
+/**
+ * Resolve any CSS expression which contains a var() usage to the ultimate real
+ * CSS expression value e.g.,
+ *
+ *    var-one: var(two);
+ *    var-two: #ff00ff;
+ *
+ *    .test {
+ *      color: var(one);
+ *    }
+ *
+ * then .test's color would be #ff00ff
+ */
+class _ResolveVarUsages extends Visitor {
+  final Map<String, VarDefinition> varDefs;
+  bool inVarDefinition = false;
+  bool inUsage = false;
+  Expressions currentExpressions;
+
+  _ResolveVarUsages(this.varDefs);
+
+  void visitTree(StyleSheet tree) {
+    visitStyleSheet(tree);
+  }
+
+  void visitVarDefinition(VarDefinition varDef) {
+    inVarDefinition = true;
+    super.visitVarDefinition(varDef);
+    inVarDefinition = false;
+  }
+
+  void visitExpressions(Expressions node) {
+    currentExpressions = node;
+    super.visitExpressions(node);
+    currentExpressions = null;
+  }
+
+  void visitVarUsage(VarUsage node) {
+    // Don't process other var() inside of a varUsage.  That implies that the
+    // default is a var() too.  Also, don't process any var() inside of a
+    // varDefinition (they're just place holders until we've resolved all real
+    // usages.
+    if (!inUsage && !inVarDefinition && currentExpressions != null) {
+      var expressions = currentExpressions.expressions;
+      var index = expressions.indexOf(node);
+      assert(index >= 0);
+      var def = varDefs[node.name];
+      if (def != null) {
+        // Found a VarDefinition use it.
+        _resolveVarUsage(currentExpressions.expressions, index, def);
+      } else if (node.defaultValues.any((e) => e is VarUsage)) {
+        // Don't have a VarDefinition need to use default values resolve all
+        // default values.
+        var terminalDefaults = [];
+        for (var defaultValue in node.defaultValues) {
+          terminalDefaults.addAll(resolveUsageTerminal(defaultValue));
+        }
+        expressions.replaceRange(index, index + 1, terminalDefaults);
+      } else {
+        // No VarDefinition but default value is a terminal expression; use it.
+        expressions.replaceRange(index, index + 1, node.defaultValues);
+      }
+    }
+
+    inUsage = true;
+    super.visitVarUsage(node);
+    inUsage = false;
+  }
+
+  List<Expression> resolveUsageTerminal(VarUsage usage) {
+    var result = [];
+
+    var varDef = varDefs[usage.name];
+    var expressions;
+    if (varDef == null) {
+      // VarDefinition not found try the defaultValues.
+      expressions = usage.defaultValues;
+    } else {
+      // Use the VarDefinition found.
+      expressions = (varDef.expression as Expressions).expressions;
+    }
+
+    for (var expr in expressions) {
+      if (expr is VarUsage) {
+        // Get terminal value.
+        result.addAll(resolveUsageTerminal(expr));
+      }
+    }
+
+    // We're at a terminal just return the VarDefinition expression.
+    if (result.isEmpty && varDef != null) {
+      result = (varDef.expression as Expressions).expressions;
+    }
+
+    return result;
+  }
+
+  _resolveVarUsage(List<Expressions> expressions, int index,
+                   VarDefinition def) {
+    var defExpressions = (def.expression as Expressions).expressions;
+    expressions.replaceRange(index, index + 1, defExpressions);
+  }
+}
+
+/** Remove all var definitions. */
+class _RemoveVarDefinitions extends Visitor {
+  void visitTree(StyleSheet tree) {
+    visitStyleSheet(tree);
+  }
+
+  void visitStyleSheet(StyleSheet ss) {
+    ss.topLevels.removeWhere((e) => e is VarDefinitionDirective);
+    super.visitStyleSheet(ss);
+  }
+
+  void visitDeclarationGroup(DeclarationGroup node) {
+    node.declarations.removeWhere((e) => e is VarDefinition);
+    super.visitDeclarationGroup(node);
+  }
+}
+
+/**
+ * Process all selectors looking for a pseudo-element in a selector.  If the
+ * name is found in our list of known pseudo-elements.  Known pseudo-elements
+ * are built when parsing a component looking for an attribute named "pseudo".
+ * The value of the pseudo attribute is the name of the custom pseudo-element.
+ * The name is mangled so Dart/JS can't directly access the pseudo-element only
+ * CSS can access a custom pseudo-element (and see issue #510, querying needs
+ * access to custom pseudo-elements).
+ *
+ * Change the custom pseudo-element to be a child of the pseudo attribute's
+ * mangled custom pseudo element name. e.g,
+ *
+ *    .test::x-box
+ *
+ * would become:
+ *
+ *    .test > *[pseudo="x-box_2"]
+ */
+class _PseudoElementExpander extends Visitor {
+  final Map<String, String> _pseudoElements;
+
+  _PseudoElementExpander(this._pseudoElements);
+
+  void visitTree(StyleSheet tree) => visitStyleSheet(tree);
+
+  visitSelector(Selector node) {
+    var selectors = node.simpleSelectorSequences;
+    for (var index = 0; index < selectors.length; index++) {
+      var selector = selectors[index].simpleSelector;
+      if (selector is PseudoElementSelector) {
+        if (_pseudoElements.containsKey(selector.name)) {
+          // Pseudo Element is a custom element.
+          var mangledName = _pseudoElements[selector.name];
+
+          var span = selectors[index].span;
+
+          var attrSelector = new AttributeSelector(
+              new Identifier('pseudo', span), css.TokenKind.EQUALS,
+              mangledName, span);
+          // The wildcard * namespace selector.
+          var wildCard = new ElementSelector(new Wildcard(span), span);
+          selectors[index] = new SimpleSelectorSequence(wildCard, span,
+                  css.TokenKind.COMBINATOR_GREATER);
+          selectors.insert(++index,
+              new SimpleSelectorSequence(attrSelector, span));
+        }
+      }
+    }
+  }
+}
+
+List<UrlInfo> findImportsInStyleSheet(StyleSheet styleSheet,
+    String packageRoot, UrlInfo inputUrl, Messages messages) {
+  var visitor = new _CssImports(packageRoot, inputUrl, messages);
+  visitor.visitTree(styleSheet);
+  return visitor.urlInfos;
+}
+
+/**
+ * Find any imports in the style sheet; normalize the style sheet href and
+ * return a list of all fully qualified CSS files.
+ */
+class _CssImports extends Visitor {
+  final String packageRoot;
+
+  /** Input url of the css file, used to normalize relative import urls. */
+  final UrlInfo inputUrl;
+
+  /** List of all imported style sheets. */
+  final List<UrlInfo> urlInfos = [];
+
+  final Messages _messages;
+
+  _CssImports(this.packageRoot, this.inputUrl, this._messages);
+
+  void visitTree(StyleSheet tree) {
+    visitStyleSheet(tree);
+  }
+
+  void visitImportDirective(ImportDirective node) {
+    var urlInfo = UrlInfo.resolve(node.import, inputUrl,
+        node.span, packageRoot, _messages, ignoreAbsolute: true);
+    if (urlInfo == null) return;
+    urlInfos.add(urlInfo);
+  }
+}
+
+StyleSheet parseCss(String content, Messages messages,
+    CompilerOptions options) {
+  if (content.trim().isEmpty) return null;
+
+  var errors = [];
+
+  // TODO(terry): Add --checked when fully implemented and error handling.
+  var stylesheet = css.parse(content, errors: errors, options:
+      [options.warningsAsErrors ? '--warnings_as_errors' : '', 'memory']);
+
+  // Note: errors aren't fatal in HTML (unless strict mode is on).
+  // So just print them as warnings.
+  for (var e in errors) {
+    messages.warning(e.message, e.span);
+  }
+
+  return stylesheet;
+}
+
+/** Find terminal definition (non VarUsage implies real CSS value). */
+VarDefinition _findTerminalVarDefinition(Map<String, VarDefinition> varDefs,
+                                        VarDefinition varDef) {
+  var expressions = varDef.expression as Expressions;
+  for (var expr in expressions.expressions) {
+    if (expr is VarUsage) {
+      var usageName = (expr as VarUsage).name;
+      var foundDef = varDefs[usageName];
+
+      // If foundDef is unknown check if defaultValues; if it exist then resolve
+      // to terminal value.
+      if (foundDef == null) {
+        // We're either a VarUsage or terminal definition if in varDefs;
+        // either way replace VarUsage with it's default value because the
+        // VarDefinition isn't found.
+        var defaultValues = (expr as VarUsage).defaultValues;
+        var replaceExprs = expressions.expressions;
+        assert(replaceExprs.length == 1);
+        replaceExprs.replaceRange(0, 1, defaultValues);
+        return varDef;
+      }
+      if (foundDef is VarDefinition) {
+        return _findTerminalVarDefinition(varDefs, foundDef);
+      }
+    } else {
+      // Return real CSS property.
+      return varDef;
+    }
+  }
+
+  // Didn't point to a var definition that existed.
+  return varDef;
+}
+
+/**
+ * Find urls imported inside style tags under [info].  If [info] is a FileInfo
+ * then process only style tags in the body (don't process any style tags in a
+ * component).  If [info] is a ComponentInfo only process style tags inside of
+ * the element are processed.  For an [info] of type FileInfo [node] is the
+ * file's document and for an [info] of type ComponentInfo then [node] is the
+ * component's element tag.
+ */
+List<UrlInfo> findUrlsImported(LibraryInfo info, UrlInfo inputUrl,
+    String packageRoot, Node node, Messages messages, CompilerOptions options) {
+  // Process any @imports inside of the <style> tag.
+  var styleProcessor =
+      new _CssStyleTag(packageRoot, info, inputUrl, messages, options);
+  styleProcessor.visit(node);
+  return styleProcessor.imports;
+}
+
+/* Process CSS inside of a style tag. */
+class _CssStyleTag extends TreeVisitor {
+  final String _packageRoot;
+
+  /** Either a FileInfo or ComponentInfo. */
+  final LibraryInfo _info;
+  final Messages _messages;
+  final CompilerOptions _options;
+
+  /**
+   * Path of the declaring file, for a [_info] of type FileInfo it's the file's
+   * path for a type ComponentInfo it's the declaring file path.
+   */
+  final UrlInfo _inputUrl;
+
+  /** List of @imports found. */
+  List<UrlInfo> imports = [];
+
+  _CssStyleTag(this._packageRoot, this._info, this._inputUrl, this._messages,
+      this._options);
+
+  void visitElement(Element node) {
+    // Don't process any style tags inside of element if we're processing a
+    // FileInfo.  The style tags inside of a component defintion will be
+    // processed when _info is a ComponentInfo.
+    if (node.tagName == 'polymer-element' && _info is FileInfo) return;
+    if (node.tagName == 'style') {
+      // Parse the contents of the scoped style tag.
+      var styleSheet = parseCss(node.nodes.single.value, _messages, _options);
+      if (styleSheet != null) {
+        _info.styleSheets.add(styleSheet);
+
+        // Find all imports return list of @imports in this style tag.
+        var urlInfos = findImportsInStyleSheet(styleSheet, _packageRoot,
+            _inputUrl, _messages);
+        imports.addAll(urlInfos);
+      }
+    }
+    super.visitElement(node);
+  }
+}