New XML parser

src/display/dom_utils.js

@@ -135,132 +135,6 @@ class DOMSVGFactory {
   }
 }
 
-class SimpleDOMNode {
-  constructor(nodeName, nodeValue) {
-    this.nodeName = nodeName;
-    this.nodeValue = nodeValue;
-
-    Object.defineProperty(this, 'parentNode', { value: null, writable: true, });
-  }
-
-  get firstChild() {
-    return this.childNodes[0];
-  }
-
-  get nextSibling() {
-    let index = this.parentNode.childNodes.indexOf(this);
-    return this.parentNode.childNodes[index + 1];
-  }
-
-  get textContent() {
-    if (!this.childNodes) {
-      return this.nodeValue || '';
-    }
-    return this.childNodes.map(function(child) {
-      return child.textContent;
-    }).join('');
-  }
-
-  hasChildNodes() {
-    return this.childNodes && this.childNodes.length > 0;
-  }
-}
-
-class SimpleXMLParser {
-  parseFromString(data) {
-    let nodes = [];
-
-    // Remove all comments and processing instructions.
-    data = data.replace(/<\?[\s\S]*?\?>|<!--[\s\S]*?-->/g, '').trim();
-    data = data.replace(/<!DOCTYPE[^>\[]+(\[[^\]]+)?[^>]+>/g, '').trim();
-
-    // Extract all text nodes and replace them with a numeric index in
-    // the nodes.
-    data = data.replace(/>([^<][\s\S]*?)</g, (all, text) => {
-      let length = nodes.length;
-      let node = new SimpleDOMNode('#text', this._decodeXML(text));
-      nodes.push(node);
-      if (node.textContent.trim().length === 0) {
-        return '><'; // Ignore whitespace.
-      }
-      return '>' + length + ',<';
-    });
-
-    // Extract all CDATA nodes.
-    data = data.replace(/<!\[CDATA\[([\s\S]*?)\]\]>/g,
-        function(all, text) {
-      let length = nodes.length;
-      let node = new SimpleDOMNode('#text', text);
-      nodes.push(node);
-      return length + ',';
-    });
-
-    // Until nodes without '<' and '>' content are present, replace them
-    // with a numeric index in the nodes.
-    let regex =
-      /<([\w\:]+)((?:[\s\w:=]|'[^']*'|"[^"]*")*)(?:\/>|>([\d,]*)<\/[^>]+>)/g;
-    let lastLength;
-    do {
-      lastLength = nodes.length;
-      data = data.replace(regex, function(all, name, attrs, data) {
-        let length = nodes.length;
-        let node = new SimpleDOMNode(name);
-        let children = [];
-        if (data) {
-          data = data.split(',');
-          data.pop();
-          data.forEach(function(child) {
-            let childNode = nodes[+child];
-            childNode.parentNode = node;
-            children.push(childNode);
-          });
-        }
-
-        node.childNodes = children;
-        nodes.push(node);
-        return length + ',';
-      });
-    } while (lastLength < nodes.length);
-
-    // We should only have one root index left, which will be last in the nodes.
-    return {
-      documentElement: nodes.pop(),
-    };
-  }
-
-  _decodeXML(text) {
-    if (text.indexOf('&') < 0) {
-      return text;
-    }
-
-    return text.replace(/&(#(x[0-9a-f]+|\d+)|\w+);/gi,
-        function(all, entityName, number) {
-      if (number) {
-        if (number[0] === 'x') {
-          number = parseInt(number.substring(1), 16);
-        } else {
-          number = +number;
-        }
-        return String.fromCharCode(number);
-      }
-
-      switch (entityName) {
-        case 'amp':
-          return '&';
-        case 'lt':
-          return '<';
-        case 'gt':
-          return '>';
-        case 'quot':
-          return '\"';
-        case 'apos':
-          return '\'';
-      }
-      return '&' + entityName + ';';
-    });
-  }
-}
-
 /**
  * Optimised CSS custom property getter/setter.
  * @class
@@ -483,5 +357,4 @@ export {
   DOMCanvasFactory,
   DOMCMapReaderFactory,
   DOMSVGFactory,
-  SimpleXMLParser,
 };

src/display/metadata.js

@@ -14,7 +14,7 @@
  */
 
 import { assert, deprecated } from '../shared/util';
-import { SimpleXMLParser } from './dom_utils';
+import { SimpleXMLParser } from './xml_parser';
 
 class Metadata {
   constructor(data) {
@@ -23,13 +23,15 @@ class Metadata {
     // Ghostscript may produce invalid metadata, so try to repair that first.
     data = this._repair(data);
 
-    // Convert the string to a DOM `Document`.
+    // Convert the string to an XML document.
     let parser = new SimpleXMLParser();
-    data = parser.parseFromString(data);
+    const xmlDocument = parser.parseFromString(data);
 
     this._metadata = Object.create(null);
 
-    this._parse(data);
+    if (xmlDocument) {
+      this._parse(xmlDocument);
+    }
   }
 
   _repair(data) {
@@ -54,8 +56,8 @@ class Metadata {
     });
   }
 
-  _parse(domDocument) {
+  _parse(xmlDocument) {
-    let rdf = domDocument.documentElement;
+    let rdf = xmlDocument.documentElement;
 
     if (rdf.nodeName.toLowerCase() !== 'rdf:rdf') { // Wrapped in <xmpmeta>
       rdf = rdf.firstChild;

src/display/xml_parser.js

@@ -0,0 +1,374 @@
+/* Copyright 2018 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// The code for XMLParserBase copied from
+// https://github.com/mozilla/shumway/blob/16451d8836fa85f4b16eeda8b4bda2fa9e2b22b0/src/avm2/natives/xml.ts
+
+const XMLParserErrorCode = {
+  NoError: 0,
+  EndOfDocument: -1,
+  UnterminatedCdat: -2,
+  UnterminatedXmlDeclaration: -3,
+  UnterminatedDoctypeDeclaration: -4,
+  UnterminatedComment: -5,
+  MalformedElement: -6,
+  OutOfMemory: -7,
+  UnterminatedAttributeValue: -8,
+  UnterminatedElement: -9,
+  ElementNeverBegun: -10,
+};
+
+function isWhitespace(s, index) {
+  const ch = s[index];
+  return ch === ' ' || ch === '\n' || ch === '\r' || ch === '\t';
+}
+
+function isWhitespaceString(s) {
+  for (let i = 0, ii = s.length; i < ii; i++) {
+    if (!isWhitespace(s, i)) {
+      return false;
+    }
+  }
+  return true;
+}
+
+class XMLParserBase {
+  _resolveEntities(s) {
+    return s.replace(/&([^;]+);/g, function (all, entity) {
+      if (entity.substring(0, 2) === '#x') {
+        return String.fromCharCode(parseInt(entity.substring(2), 16));
+      } else if (entity.substring(0, 1) === '#') {
+        return String.fromCharCode(parseInt(entity.substring(1), 10));
+      }
+      switch (entity) {
+        case 'lt':
+          return '<';
+        case 'gt':
+          return '>';
+        case 'amp':
+          return '&';
+        case 'quot':
+          return '\"';
+      }
+      return this.onResolveEntity(entity);
+    });
+  }
+
+  _parseContent(s, start) {
+    let pos = start, name, attributes = [];
+
+    function skipWs() {
+      while (pos < s.length && isWhitespace(s, pos)) {
+        ++pos;
+      }
+    }
+
+    while (pos < s.length && !isWhitespace(s, pos) &&
+           s[pos] !== '>' && s[pos] !== '/') {
+      ++pos;
+    }
+    name = s.substring(start, pos);
+    skipWs();
+    while (pos < s.length && s[pos] !== '>' &&
+           s[pos] !== '/' && s[pos] !== '?') {
+      skipWs();
+      let attrName = '', attrValue = '';
+      while (pos < s.length && !isWhitespace(s, pos) && s[pos] !== '=') {
+        attrName += s[pos];
+        ++pos;
+      }
+      skipWs();
+      if (s[pos] !== '=') {
+        return null;
+      }
+      ++pos;
+      skipWs();
+      const attrEndChar = s[pos];
+      if (attrEndChar !== '\"' && attrEndChar !== '\'') {
+        return null;
+      }
+      const attrEndIndex = s.indexOf(attrEndChar, ++pos);
+      if (attrEndIndex < 0) {
+        return null;
+      }
+      attrValue = s.substring(pos, attrEndIndex);
+      attributes.push({
+        name: attrName,
+        value: this._resolveEntities(attrValue),
+      });
+      pos = attrEndIndex + 1;
+      skipWs();
+    }
+    return {
+      name,
+      attributes,
+      parsed: pos - start,
+    };
+  }
+
+  _parseProcessingInstruction(s, start) {
+    let pos = start, name, value;
+
+    function skipWs() {
+      while (pos < s.length && isWhitespace(s, pos)) {
+        ++pos;
+      }
+    }
+
+    while (pos < s.length && !isWhitespace(s, pos) &&
+           s[pos] !== '>' && s[pos] !== '/') {
+      ++pos;
+    }
+    name = s.substring(start, pos);
+    skipWs();
+    const attrStart = pos;
+    while (pos < s.length && (s[pos] !== '?' || s[pos + 1] !== '>')) {
+      ++pos;
+    }
+    value = s.substring(attrStart, pos);
+    return {
+      name,
+      value,
+      parsed: pos - start,
+    };
+  }
+
+  parseXml(s) {
+    let i = 0;
+    while (i < s.length) {
+      const ch = s[i];
+      let j = i;
+      if (ch === '<') {
+        ++j;
+        const ch2 = s[j];
+        let q;
+        switch (ch2) {
+          case '/':
+            ++j;
+            q = s.indexOf('>', j);
+            if (q < 0) {
+              this.onError(XMLParserErrorCode.UnterminatedElement);
+              return;
+            }
+            this.onEndElement(s.substring(j, q));
+            j = q + 1;
+            break;
+          case '?':
+            ++j;
+            const pi = this._parseProcessingInstruction(s, j);
+            if (s.substring(j + pi.parsed, j + pi.parsed + 2) !== '?>') {
+              this.onError(XMLParserErrorCode.UnterminatedXmlDeclaration);
+              return;
+            }
+            this.onPi(pi.name, pi.value);
+            j += pi.parsed + 2;
+            break;
+          case '!':
+            if (s.substring(j + 1, j + 3) === '--') {
+              q = s.indexOf('-->', j + 3);
+              if (q < 0) {
+                this.onError(XMLParserErrorCode.UnterminatedComment);
+                return;
+              }
+              this.onComment(s.substring(j + 3, q));
+              j = q + 3;
+            } else if (s.substring(j + 1, j + 8) === '[CDATA[') {
+              q = s.indexOf(']]>', j + 8);
+              if (q < 0) {
+                this.onError(XMLParserErrorCode.UnterminatedCdat);
+                return;
+              }
+              this.onCdata(s.substring(j + 8, q));
+              j = q + 3;
+            } else if (s.substring(j + 1, j + 8) === 'DOCTYPE') {
+              const q2 = s.indexOf('[', j + 8);
+              let complexDoctype = false;
+              q = s.indexOf('>', j + 8);
+              if (q < 0) {
+                this.onError(XMLParserErrorCode.UnterminatedDoctypeDeclaration);
+                return;
+              }
+              if (q2 > 0 && q > q2) {
+                q = s.indexOf(']>', j + 8);
+                if (q < 0) {
+                  this.onError(
+                    XMLParserErrorCode.UnterminatedDoctypeDeclaration);
+                  return;
+                }
+                complexDoctype = true;
+              }
+              const doctypeContent =
+                s.substring(j + 8, q + (complexDoctype ? 1 : 0));
+              this.onDoctype(doctypeContent);
+              j = q + (complexDoctype ? 2 : 1);
+            } else {
+              this.onError(XMLParserErrorCode.MalformedElement);
+              return;
+            }
+            break;
+          default:
+            const content = this._parseContent(s, j);
+            if (content === null) {
+              this.onError(XMLParserErrorCode.MalformedElement);
+              return;
+            }
+            let isClosed = false;
+            if (s.substring(j + content.parsed,
+                            j + content.parsed + 2) === '/>') {
+              isClosed = true;
+            } else if (s.substring(j + content.parsed,
+                       j + content.parsed + 1) !== '>') {
+              this.onError(XMLParserErrorCode.UnterminatedElement);
+              return;
+            }
+            this.onBeginElement(content.name, content.attributes, isClosed);
+            j += content.parsed + (isClosed ? 2 : 1);
+            break;
+        }
+      } else {
+        while (j < s.length && s[j] !== '<') {
+          j++;
+        }
+        const text = s.substring(i, j);
+        this.onText(this._resolveEntities(text));
+      }
+      i = j;
+    }
+  }
+
+  onResolveEntity(name) {
+    return `&${name};`;
+  }
+
+  onPi(name, value) { }
+
+  onComment(text) { }
+
+  onCdata(text) { }
+
+  onDoctype(doctypeContent) { }
+
+  onText(text) { }
+
+  onBeginElement(name, attributes, isEmpty) { }
+
+  onEndElement(name) { }
+
+  onError(code) { }
+}
+
+class SimpleDOMNode {
+  constructor(nodeName, nodeValue) {
+    this.nodeName = nodeName;
+    this.nodeValue = nodeValue;
+
+    Object.defineProperty(this, 'parentNode', { value: null, writable: true, });
+  }
+
+  get firstChild() {
+    return this.childNodes[0];
+  }
+
+  get nextSibling() {
+    let index = this.parentNode.childNodes.indexOf(this);
+    return this.parentNode.childNodes[index + 1];
+  }
+
+  get textContent() {
+    if (!this.childNodes) {
+      return this.nodeValue || '';
+    }
+    return this.childNodes.map(function(child) {
+      return child.textContent;
+    }).join('');
+  }
+
+  hasChildNodes() {
+    return this.childNodes && this.childNodes.length > 0;
+  }
+}
+
+class SimpleXMLParser extends XMLParserBase {
+  constructor() {
+    super();
+    this._currentFragment = null;
+    this._stack = null;
+    this._errorCode = XMLParserErrorCode.NoError;
+  }
+
+  parseFromString(data) {
+    this._currentFragment = [];
+    this._stack = [];
+    this._errorCode = XMLParserErrorCode.NoError;
+
+    this.parseXml(data);
+
+    if (this._errorCode !== XMLParserErrorCode.NoError) {
+      return undefined; // return undefined on error
+    }
+
+    // We should only have one root.
+    const [documentElement] = this._currentFragment;
+    return { documentElement, };
+  }
+
+  onResolveEntity(name) {
+    switch (name) {
+      case 'apos':
+        return '\'';
+    }
+    return super.onResolveEntity(name);
+  }
+
+  onText(text) {
+    if (isWhitespaceString(text)) {
+      return;
+    }
+    const node = new SimpleDOMNode('#text', text);
+    this._currentFragment.push(node);
+  }
+
+  onCdata(text) {
+    const node = new SimpleDOMNode('#text', text);
+    this._currentFragment.push(node);
+  }
+
+  onBeginElement(name, attributes, isEmpty) {
+    const node = new SimpleDOMNode(name);
+    node.childNodes = [];
+    this._currentFragment.push(node);
+    if (isEmpty) {
+      return;
+    }
+    this._stack.push(this._currentFragment);
+    this._currentFragment = node.childNodes;
+  }
+
+  onEndElement(name) {
+    this._currentFragment = this._stack.pop();
+    const lastElement = this._currentFragment[this._currentFragment.length - 1];
+    for (let i = 0, ii = lastElement.childNodes.length; i < ii; i++) {
+      lastElement.childNodes[i].parentNode = lastElement;
+    }
+  }
+
+  onError(code) {
+    this._errorCode = code;
+  }
+}
+
+export {
+  SimpleXMLParser,
+};