1 files changed, 525 insertions, 0 deletions
diff --git a/catapult/third_party/polymer/components/shadycss/src/apply-shim.js b/catapult/third_party/polymer/components/shadycss/src/apply-shim.js
new file mode 100644
index 00000000..e4bc9cdf
--- /dev/null
+++ b/catapult/third_party/polymer/components/shadycss/src/apply-shim.js
@@ -0,0 +1,525 @@
+/**
+@license
+Copyright (c) 2017 The Polymer Project Authors. All rights reserved.
+This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
+The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
+The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
+Code distributed by Google as part of the polymer project is also
+subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
+*/
+/*
+ * The apply shim simulates the behavior of `@apply` proposed at
+ * https://tabatkins.github.io/specs/css-apply-rule/.
+ * The approach is to convert a property like this:
+ *
+ *    --foo: {color: red; background: blue;}
+ *
+ * to this:
+ *
+ *    --foo_-_color: red;
+ *    --foo_-_background: blue;
+ *
+ * Then where `@apply --foo` is used, that is converted to:
+ *
+ *    color: var(--foo_-_color);
+ *    background: var(--foo_-_background);
+ *
+ * This approach generally works but there are some issues and limitations.
+ * Consider, for example, that somewhere *between* where `--foo` is set and used,
+ * another element sets it to:
+ *
+ *    --foo: { border: 2px solid red; }
+ *
+ * We must now ensure that the color and background from the previous setting
+ * do not apply. This is accomplished by changing the property set to this:
+ *
+ *    --foo_-_border: 2px solid red;
+ *    --foo_-_color: initial;
+ *    --foo_-_background: initial;
+ *
+ * This works but introduces one new issue.
+ * Consider this setup at the point where the `@apply` is used:
+ *
+ *    background: orange;
+ *    `@apply` --foo;
+ *
+ * In this case the background will be unset (initial) rather than the desired
+ * `orange`. We address this by altering the property set to use a fallback
+ * value like this:
+ *
+ *    color: var(--foo_-_color);
+ *    background: var(--foo_-_background, orange);
+ *    border: var(--foo_-_border);
+ *
+ * Note that the default is retained in the property set and the `background` is
+ * the desired `orange`. This leads us to a limitation.
+ *
+ * Limitation 1:
+
+ * Only properties in the rule where the `@apply`
+ * is used are considered as default values.
+ * If another rule matches the element and sets `background` with
+ * less specificity than the rule in which `@apply` appears,
+ * the `background` will not be set.
+ *
+ * Limitation 2:
+ *
+ * When using Polymer's `updateStyles` api, new properties may not be set for
+ * `@apply` properties.
+
+*/
+
+'use strict';
+
+import {forEachRule, processVariableAndFallback, rulesForStyle, toCssText, gatherStyleText} from './style-util.js';
+import {MIXIN_MATCH, VAR_ASSIGN} from './common-regex.js';
+import {detectMixin} from './common-utils.js';
+import {StyleNode} from './css-parse.js'; // eslint-disable-line no-unused-vars
+
+const APPLY_NAME_CLEAN = /;\s*/m;
+const INITIAL_INHERIT = /^\s*(initial)|(inherit)\s*$/;
+const IMPORTANT = /\s*!important/;
+
+// separator used between mixin-name and mixin-property-name when producing properties
+// NOTE: plain '-' may cause collisions in user styles
+const MIXIN_VAR_SEP = '_-_';
+
+/**
+ * @typedef {!Object<string, string>}
+ */
+let PropertyEntry; // eslint-disable-line no-unused-vars
+
+/**
+ * @typedef {!Object<string, boolean>}
+ */
+let DependantsEntry; // eslint-disable-line no-unused-vars
+
+/** @typedef {{
+ *    properties: PropertyEntry,
+ *    dependants: DependantsEntry
+ * }}
+ */
+let MixinMapEntry; // eslint-disable-line no-unused-vars
+
+// map of mixin to property names
+// --foo: {border: 2px} -> {properties: {(--foo, ['border'])}, dependants: {'element-name': proto}}
+class MixinMap {
+  constructor() {
+    /** @type {!Object<string, !MixinMapEntry>} */
+    this._map = {};
+  }
+  /**
+   * @param {string} name
+   * @param {!PropertyEntry} props
+   */
+  set(name, props) {
+    name = name.trim();
+    this._map[name] = {
+      properties: props,
+      dependants: {}
+    }
+  }
+  /**
+   * @param {string} name
+   * @return {MixinMapEntry}
+   */
+  get(name) {
+    name = name.trim();
+    return this._map[name] || null;
+  }
+}
+
+/**
+ * Callback for when an element is marked invalid
+ * @type {?function(string)}
+ */
+let invalidCallback = null;
+
+/** @unrestricted */
+class ApplyShim {
+  constructor() {
+    /** @type {?string} */
+    this._currentElement = null;
+    /** @type {HTMLMetaElement} */
+    this._measureElement = null;
+    this._map = new MixinMap();
+  }
+  /**
+   * return true if `cssText` contains a mixin definition or consumption
+   * @param {string} cssText
+   * @return {boolean}
+   */
+  detectMixin(cssText) {
+    return detectMixin(cssText);
+  }
+
+  /**
+   * Gather styles into one style for easier processing
+   * @param {!HTMLTemplateElement} template
+   * @return {HTMLStyleElement}
+   */
+  gatherStyles(template) {
+    const styleText = gatherStyleText(template.content);
+    if (styleText) {
+      const style = /** @type {!HTMLStyleElement} */(document.createElement('style'));
+      style.textContent = styleText;
+      template.content.insertBefore(style, template.content.firstChild);
+      return style;
+    }
+    return null;
+  }
+  /**
+   * @param {!HTMLTemplateElement} template
+   * @param {string} elementName
+   * @return {StyleNode}
+   */
+  transformTemplate(template, elementName) {
+    if (template._gatheredStyle === undefined) {
+      template._gatheredStyle = this.gatherStyles(template);
+    }
+    /** @type {HTMLStyleElement} */
+    const style = template._gatheredStyle;
+    return style ? this.transformStyle(style, elementName) : null;
+  }
+  /**
+   * @param {!HTMLStyleElement} style
+   * @param {string} elementName
+   * @return {StyleNode}
+   */
+  transformStyle(style, elementName = '') {
+    let ast = rulesForStyle(style);
+    this.transformRules(ast, elementName);
+    style.textContent = toCssText(ast);
+    return ast;
+  }
+  /**
+   * @param {!HTMLStyleElement} style
+   * @return {StyleNode}
+   */
+  transformCustomStyle(style) {
+    let ast = rulesForStyle(style);
+    forEachRule(ast, (rule) => {
+      if (rule['selector'] === ':root') {
+        rule['selector'] = 'html';
+      }
+      this.transformRule(rule);
+    })
+    style.textContent = toCssText(ast);
+    return ast;
+  }
+  /**
+   * @param {StyleNode} rules
+   * @param {string} elementName
+   */
+  transformRules(rules, elementName) {
+    this._currentElement = elementName;
+    forEachRule(rules, (r) => {
+      this.transformRule(r);
+    });
+    this._currentElement = null;
+  }
+  /**
+   * @param {!StyleNode} rule
+   */
+  transformRule(rule) {
+    rule['cssText'] = this.transformCssText(rule['parsedCssText'], rule);
+    // :root was only used for variable assignment in property shim,
+    // but generates invalid selectors with real properties.
+    // replace with `:host > *`, which serves the same effect
+    if (rule['selector'] === ':root') {
+      rule['selector'] = ':host > *';
+    }
+  }
+  /**
+   * @param {string} cssText
+   * @param {!StyleNode} rule
+   * @return {string}
+   */
+  transformCssText(cssText, rule) {
+    // produce variables
+    cssText = cssText.replace(VAR_ASSIGN, (matchText, propertyName, valueProperty, valueMixin) =>
+      this._produceCssProperties(matchText, propertyName, valueProperty, valueMixin, rule));
+    // consume mixins
+    return this._consumeCssProperties(cssText, rule);
+  }
+  /**
+   * @param {string} property
+   * @return {string}
+   */
+  _getInitialValueForProperty(property) {
+    if (!this._measureElement) {
+      this._measureElement = /** @type {HTMLMetaElement} */(document.createElement('meta'));
+      this._measureElement.setAttribute('apply-shim-measure', '');
+      this._measureElement.style.all = 'initial';
+      document.head.appendChild(this._measureElement);
+    }
+    return window.getComputedStyle(this._measureElement).getPropertyValue(property);
+  }
+  /**
+   * Walk over all rules before this rule to find fallbacks for mixins
+   *
+   * @param {!StyleNode} startRule
+   * @return {!Object}
+   */
+  _fallbacksFromPreviousRules(startRule) {
+    // find the "top" rule
+    let topRule = startRule;
+    while (topRule['parent']) {
+      topRule = topRule['parent'];
+    }
+    const fallbacks = {};
+    let seenStartRule = false;
+    forEachRule(topRule, (r) => {
+      // stop when we hit the input rule
+      seenStartRule = seenStartRule || r === startRule;
+      if (seenStartRule) {
+        return;
+      }
+      // NOTE: Only matching selectors are "safe" for this fallback processing
+      // It would be prohibitive to run `matchesSelector()` on each selector,
+      // so we cheat and only check if the same selector string is used, which
+      // guarantees things like specificity matching
+      if (r['selector'] === startRule['selector']) {
+        Object.assign(fallbacks, this._cssTextToMap(r['parsedCssText']));
+      }
+    });
+    return fallbacks;
+  }
+  /**
+   * replace mixin consumption with variable consumption
+   * @param {string} text
+   * @param {!StyleNode=} rule
+   * @return {string}
+   */
+  _consumeCssProperties(text, rule) {
+    /** @type {Array} */
+    let m = null;
+    // loop over text until all mixins with defintions have been applied
+    while((m = MIXIN_MATCH.exec(text))) {
+      let matchText = m[0];
+      let mixinName = m[1];
+      let idx = m.index;
+      // collect properties before apply to be "defaults" if mixin might override them
+      // match includes a "prefix", so find the start and end positions of @apply
+      let applyPos = idx + matchText.indexOf('@apply');
+      let afterApplyPos = idx + matchText.length;
+      // find props defined before this @apply
+      let textBeforeApply = text.slice(0, applyPos);
+      let textAfterApply = text.slice(afterApplyPos);
+      let defaults = rule ? this._fallbacksFromPreviousRules(rule) : {};
+      Object.assign(defaults, this._cssTextToMap(textBeforeApply));
+      let replacement = this._atApplyToCssProperties(mixinName, defaults);
+      // use regex match position to replace mixin, keep linear processing time
+      text = `${textBeforeApply}${replacement}${textAfterApply}`;
+      // move regex search to _after_ replacement
+      MIXIN_MATCH.lastIndex = idx + replacement.length;
+    }
+    return text;
+  }
+  /**
+   * produce variable consumption at the site of mixin consumption
+   * `@apply` --foo; -> for all props (${propname}: var(--foo_-_${propname}, ${fallback[propname]}}))
+   * Example:
+   *  border: var(--foo_-_border); padding: var(--foo_-_padding, 2px)
+   *
+   * @param {string} mixinName
+   * @param {Object} fallbacks
+   * @return {string}
+   */
+  _atApplyToCssProperties(mixinName, fallbacks) {
+    mixinName = mixinName.replace(APPLY_NAME_CLEAN, '');
+    let vars = [];
+    let mixinEntry = this._map.get(mixinName);
+    // if we depend on a mixin before it is created
+    // make a sentinel entry in the map to add this element as a dependency for when it is defined.
+    if (!mixinEntry) {
+      this._map.set(mixinName, {});
+      mixinEntry = this._map.get(mixinName);
+    }
+    if (mixinEntry) {
+      if (this._currentElement) {
+        mixinEntry.dependants[this._currentElement] = true;
+      }
+      let p, parts, f;
+      const properties = mixinEntry.properties;
+      for (p in properties) {
+        f = fallbacks && fallbacks[p];
+        parts = [p, ': var(', mixinName, MIXIN_VAR_SEP, p];
+        if (f) {
+          parts.push(',', f.replace(IMPORTANT, ''));
+        }
+        parts.push(')');
+        if (IMPORTANT.test(properties[p])) {
+          parts.push(' !important');
+        }
+        vars.push(parts.join(''));
+      }
+    }
+    return vars.join('; ');
+  }
+
+  /**
+   * @param {string} property
+   * @param {string} value
+   * @return {string}
+   */
+  _replaceInitialOrInherit(property, value) {
+    let match = INITIAL_INHERIT.exec(value);
+    if (match) {
+      if (match[1]) {
+        // initial
+        // replace `initial` with the concrete initial value for this property
+        value = this._getInitialValueForProperty(property);
+      } else {
+        // inherit
+        // with this purposfully illegal value, the variable will be invalid at
+        // compute time (https://www.w3.org/TR/css-variables/#invalid-at-computed-value-time)
+        // and for inheriting values, will behave similarly
+        // we cannot support the same behavior for non inheriting values like 'border'
+        value = 'apply-shim-inherit';
+      }
+    }
+    return value;
+  }
+
+  /**
+   * "parse" a mixin definition into a map of properties and values
+   * cssTextToMap('border: 2px solid black') -> ('border', '2px solid black')
+   * @param {string} text
+   * @param {boolean=} replaceInitialOrInherit
+   * @return {!Object<string, string>}
+   */
+  _cssTextToMap(text, replaceInitialOrInherit = false) {
+    let props = text.split(';');
+    let property, value;
+    let out = {};
+    for (let i = 0, p, sp; i < props.length; i++) {
+      p = props[i];
+      if (p) {
+        sp = p.split(':');
+        // ignore lines that aren't definitions like @media
+        if (sp.length > 1) {
+          property = sp[0].trim();
+          // some properties may have ':' in the value, like data urls
+          value = sp.slice(1).join(':');
+          if (replaceInitialOrInherit) {
+            value = this._replaceInitialOrInherit(property, value);
+          }
+          out[property] = value;
+        }
+      }
+    }
+    return out;
+  }
+
+  /**
+   * @param {MixinMapEntry} mixinEntry
+   */
+  _invalidateMixinEntry(mixinEntry) {
+    if (!invalidCallback) {
+      return;
+    }
+    for (let elementName in mixinEntry.dependants) {
+      if (elementName !== this._currentElement) {
+        invalidCallback(elementName);
+      }
+    }
+  }
+
+  /**
+   * @param {string} matchText
+   * @param {string} propertyName
+   * @param {?string} valueProperty
+   * @param {?string} valueMixin
+   * @param {!StyleNode} rule
+   * @return {string}
+   */
+  _produceCssProperties(matchText, propertyName, valueProperty, valueMixin, rule) {
+    // handle case where property value is a mixin
+    if (valueProperty) {
+      // form: --mixin2: var(--mixin1), where --mixin1 is in the map
+      processVariableAndFallback(valueProperty, (prefix, value) => {
+        if (value && this._map.get(value)) {
+          valueMixin = `@apply ${value};`
+        }
+      });
+    }
+    if (!valueMixin) {
+      return matchText;
+    }
+    let mixinAsProperties = this._consumeCssProperties('' + valueMixin, rule);
+    let prefix = matchText.slice(0, matchText.indexOf('--'));
+    // `initial` and `inherit` as properties in a map should be replaced because
+    // these keywords are eagerly evaluated when the mixin becomes CSS Custom Properties,
+    // and would set the variable value, rather than carry the keyword to the `var()` usage.
+    let mixinValues = this._cssTextToMap(mixinAsProperties, true);
+    let combinedProps = mixinValues;
+    let mixinEntry = this._map.get(propertyName);
+    let oldProps = mixinEntry && mixinEntry.properties;
+    if (oldProps) {
+      // NOTE: since we use mixin, the map of properties is updated here
+      // and this is what we want.
+      combinedProps = Object.assign(Object.create(oldProps), mixinValues);
+    } else {
+      this._map.set(propertyName, combinedProps);
+    }
+    let out = [];
+    let p, v;
+    // set variables defined by current mixin
+    let needToInvalidate = false;
+    for (p in combinedProps) {
+      v = mixinValues[p];
+      // if property not defined by current mixin, set initial
+      if (v === undefined) {
+        v = 'initial';
+      }
+      if (oldProps && !(p in oldProps)) {
+        needToInvalidate = true;
+      }
+      out.push(`${propertyName}${MIXIN_VAR_SEP}${p}: ${v}`);
+    }
+    if (needToInvalidate) {
+      this._invalidateMixinEntry(mixinEntry);
+    }
+    if (mixinEntry) {
+      mixinEntry.properties = combinedProps;
+    }
+    // because the mixinMap is global, the mixin might conflict with
+    // a different scope's simple variable definition:
+    // Example:
+    // some style somewhere:
+    // --mixin1:{ ... }
+    // --mixin2: var(--mixin1);
+    // some other element:
+    // --mixin1: 10px solid red;
+    // --foo: var(--mixin1);
+    // In this case, we leave the original variable definition in place.
+    if (valueProperty) {
+      prefix = `${matchText};${prefix}`;
+    }
+    return `${prefix}${out.join('; ')};`;
+  }
+}
+
+/* exports */
+/* eslint-disable no-self-assign */
+ApplyShim.prototype['detectMixin'] = ApplyShim.prototype.detectMixin;
+ApplyShim.prototype['transformStyle'] = ApplyShim.prototype.transformStyle;
+ApplyShim.prototype['transformCustomStyle'] = ApplyShim.prototype.transformCustomStyle;
+ApplyShim.prototype['transformRules'] = ApplyShim.prototype.transformRules;
+ApplyShim.prototype['transformRule'] = ApplyShim.prototype.transformRule;
+ApplyShim.prototype['transformTemplate'] = ApplyShim.prototype.transformTemplate;
+ApplyShim.prototype['_separator'] = MIXIN_VAR_SEP;
+/* eslint-enable no-self-assign */
+Object.defineProperty(ApplyShim.prototype, 'invalidCallback', {
+  /** @return {?function(string)} */
+  get() {
+    return invalidCallback;
+  },
+  /** @param {?function(string)} cb */
+  set(cb) {
+    invalidCallback = cb;
+  }
+});
+
+export default ApplyShim;