Merge pull request #12997 from Snuffleupagus/metadata-worker

Move the Metadata parsing to the worker-thread

src/core/core_utils.js

@@ -316,8 +316,54 @@ function collectActions(xref, dict, eventType) {
   return objectSize(actions) > 0 ? actions : null;
 }
 
+const XMLEntities = {
+  /* < */ 0x3c: "&lt;",
+  /* > */ 0x3e: "&gt;",
+  /* & */ 0x26: "&amp;",
+  /* " */ 0x22: "&quot;",
+  /* ' */ 0x27: "&apos;",
+};
+
+function encodeToXmlString(str) {
+  const buffer = [];
+  let start = 0;
+  for (let i = 0, ii = str.length; i < ii; i++) {
+    const char = str.codePointAt(i);
+    if (0x20 <= char && char <= 0x7e) {
+      // ascii
+      const entity = XMLEntities[char];
+      if (entity) {
+        if (start < i) {
+          buffer.push(str.substring(start, i));
+        }
+        buffer.push(entity);
+        start = i + 1;
+      }
+    } else {
+      if (start < i) {
+        buffer.push(str.substring(start, i));
+      }
+      buffer.push(`&#x${char.toString(16).toUpperCase()};`);
+      if (char > 0xd7ff && (char < 0xe000 || char > 0xfffd)) {
+        // char is represented by two u16
+        i++;
+      }
+      start = i + 1;
+    }
+  }
+
+  if (buffer.length === 0) {
+    return str;
+  }
+  if (start < str.length) {
+    buffer.push(str.substring(start, str.length));
+  }
+  return buffer.join("");
+}
+
 export {
   collectActions,
+  encodeToXmlString,
   escapePDFName,
   getArrayLookupTableFactory,
   getInheritableProperty,

src/core/metadata_parser.js

@@ -0,0 +1,146 @@
+/* Copyright 2012 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.
+ */
+
+import { SimpleXMLParser } from "./xml_parser.js";
+
+class MetadataParser {
+  constructor(data) {
+    // Ghostscript may produce invalid metadata, so try to repair that first.
+    data = this._repair(data);
+
+    // Convert the string to an XML document.
+    const parser = new SimpleXMLParser({ lowerCaseName: true });
+    const xmlDocument = parser.parseFromString(data);
+
+    this._metadataMap = new Map();
+    this._data = data;
+
+    if (xmlDocument) {
+      this._parse(xmlDocument);
+    }
+  }
+
+  _repair(data) {
+    // Start by removing any "junk" before the first tag (see issue 10395).
+    return data
+      .replace(/^[^<]+/, "")
+      .replace(/>\\376\\377([^<]+)/g, function (all, codes) {
+        const bytes = codes
+          .replace(/\\([0-3])([0-7])([0-7])/g, function (code, d1, d2, d3) {
+            return String.fromCharCode(d1 * 64 + d2 * 8 + d3 * 1);
+          })
+          .replace(/&(amp|apos|gt|lt|quot);/g, function (str, name) {
+            switch (name) {
+              case "amp":
+                return "&";
+              case "apos":
+                return "'";
+              case "gt":
+                return ">";
+              case "lt":
+                return "<";
+              case "quot":
+                return '"';
+            }
+            throw new Error(`_repair: ${name} isn't defined.`);
+          });
+
+        const charBuf = [];
+        for (let i = 0, ii = bytes.length; i < ii; i += 2) {
+          const code = bytes.charCodeAt(i) * 256 + bytes.charCodeAt(i + 1);
+          if (
+            code >= /* Space = */ 32 &&
+            code < /* Delete = */ 127 &&
+            code !== /* '<' = */ 60 &&
+            code !== /* '>' = */ 62 &&
+            code !== /* '&' = */ 38
+          ) {
+            charBuf.push(String.fromCharCode(code));
+          } else {
+            charBuf.push(
+              "&#x" + (0x10000 + code).toString(16).substring(1) + ";"
+            );
+          }
+        }
+        return ">" + charBuf.join("");
+      });
+  }
+
+  _getSequence(entry) {
+    const name = entry.nodeName;
+    if (name !== "rdf:bag" && name !== "rdf:seq" && name !== "rdf:alt") {
+      return null;
+    }
+    return entry.childNodes.filter(node => node.nodeName === "rdf:li");
+  }
+
+  _parseArray(entry) {
+    if (!entry.hasChildNodes()) {
+      return;
+    }
+    // Child must be a Bag (unordered array) or a Seq.
+    const [seqNode] = entry.childNodes;
+    const sequence = this._getSequence(seqNode) || [];
+
+    this._metadataMap.set(
+      entry.nodeName,
+      sequence.map(node => node.textContent.trim())
+    );
+  }
+
+  _parse(xmlDocument) {
+    let rdf = xmlDocument.documentElement;
+
+    if (rdf.nodeName !== "rdf:rdf") {
+      // Wrapped in <xmpmeta>
+      rdf = rdf.firstChild;
+      while (rdf && rdf.nodeName !== "rdf:rdf") {
+        rdf = rdf.nextSibling;
+      }
+    }
+
+    if (!rdf || rdf.nodeName !== "rdf:rdf" || !rdf.hasChildNodes()) {
+      return;
+    }
+
+    for (const desc of rdf.childNodes) {
+      if (desc.nodeName !== "rdf:description") {
+        continue;
+      }
+
+      for (const entry of desc.childNodes) {
+        const name = entry.nodeName;
+        switch (name) {
+          case "#text":
+            continue;
+          case "dc:creator":
+          case "dc:subject":
+            this._parseArray(entry);
+            continue;
+        }
+        this._metadataMap.set(name, entry.textContent.trim());
+      }
+    }
+  }
+
+  get serializable() {
+    return {
+      parsedData: this._metadataMap,
+      rawData: this._data,
+    };
+  }
+}
+
+export { MetadataParser };

src/core/obj.js

@@ -59,6 +59,7 @@ import { Lexer, Parser } from "./parser.js";
 import { CipherTransformFactory } from "./crypto.js";
 import { ColorSpace } from "./colorspace.js";
 import { GlobalImageCache } from "./image_utils.js";
+import { MetadataParser } from "./metadata_parser.js";
 
 function fetchDestination(dest) {
   return isDict(dest) ? dest.get("D") : dest;
@@ -131,20 +132,22 @@ class Catalog {
       this.xref.encrypt && this.xref.encrypt.encryptMetadata
     );
     const stream = this.xref.fetch(streamRef, suppressEncryption);
-    let metadata;
+    let metadata = null;
 
-    if (stream && isDict(stream.dict)) {
+    if (isStream(stream) && isDict(stream.dict)) {
       const type = stream.dict.get("Type");
       const subtype = stream.dict.get("Subtype");
 
       if (isName(type, "Metadata") && isName(subtype, "XML")) {
         // XXX: This should examine the charset the XML document defines,
-        // however since there are currently no real means to decode
-        // arbitrary charsets, let's just hope that the author of the PDF
-        // was reasonable enough to stick with the XML default charset,
-        // which is UTF-8.
+        // however since there are currently no real means to decode arbitrary
+        // charsets, let's just hope that the author of the PDF was reasonable
+        // enough to stick with the XML default charset, which is UTF-8.
         try {
-          metadata = stringToUTF8String(bytesToString(stream.getBytes()));
+          const data = stringToUTF8String(bytesToString(stream.getBytes()));
+          if (data) {
+            metadata = new MetadataParser(data).serializable;
+          }
         } catch (e) {
           if (e instanceof MissingDataException) {
             throw e;

src/core/writer.js

@@ -16,7 +16,7 @@
 import { bytesToString, escapeString, warn } from "../shared/util.js";
 import { Dict, isDict, isName, isRef, isStream, Name } from "./primitives.js";
 import { escapePDFName, parseXFAPath } from "./core_utils.js";
-import { SimpleDOMNode, SimpleXMLParser } from "../shared/xml_parser.js";
+import { SimpleDOMNode, SimpleXMLParser } from "./xml_parser.js";
 import { calculateMD5 } from "./crypto.js";
 
 function writeDict(dict, buffer, transform) {

src/core/xfa/parser.js

@@ -14,7 +14,7 @@
  */
 
 import { $clean, $finalize, $onChild, $onText } from "./xfa_object.js";
-import { XMLParserBase, XMLParserErrorCode } from "../../shared/xml_parser.js";
+import { XMLParserBase, XMLParserErrorCode } from "../xml_parser.js";
 import { Builder } from "./builder.js";
 import { warn } from "../../shared/util.js";
 

src/core/xml_parser.js

@@ -0,0 +1,506 @@
+/* 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
+
+import { encodeToXmlString } from "./core_utils.js";
+
+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, (all, entity) => {
+      if (entity.substring(0, 2) === "#x") {
+        return String.fromCodePoint(parseInt(entity.substring(2), 16));
+      } else if (entity.substring(0, 1) === "#") {
+        return String.fromCodePoint(parseInt(entity.substring(1), 10));
+      }
+      switch (entity) {
+        case "lt":
+          return "<";
+        case "gt":
+          return ">";
+        case "amp":
+          return "&";
+        case "quot":
+          return '"';
+        case "apos":
+          return "'";
+      }
+      return this.onResolveEntity(entity);
+    });
+  }
+
+  _parseContent(s, start) {
+    const attributes = [];
+    let pos = start;
+
+    function skipWs() {
+      while (pos < s.length && isWhitespace(s, pos)) {
+        ++pos;
+      }
+    }
+
+    while (
+      pos < s.length &&
+      !isWhitespace(s, pos) &&
+      s[pos] !== ">" &&
+      s[pos] !== "/"
+    ) {
+      ++pos;
+    }
+    const 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;
+
+    function skipWs() {
+      while (pos < s.length && isWhitespace(s, pos)) {
+        ++pos;
+      }
+    }
+
+    while (
+      pos < s.length &&
+      !isWhitespace(s, pos) &&
+      s[pos] !== ">" &&
+      s[pos] !== "/"
+    ) {
+      ++pos;
+    }
+    const name = s.substring(start, pos);
+    skipWs();
+    const attrStart = pos;
+    while (pos < s.length && (s[pos] !== "?" || s[pos + 1] !== ">")) {
+      ++pos;
+    }
+    const 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 && this.childNodes[0];
+  }
+
+  get nextSibling() {
+    const childNodes = this.parentNode.childNodes;
+    if (!childNodes) {
+      return undefined;
+    }
+    const index = childNodes.indexOf(this);
+    if (index === -1) {
+      return undefined;
+    }
+    return 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;
+  }
+
+  /**
+   * Search a node in the tree with the given path
+   * foo.bar[nnn], i.e. find the nnn-th node named
+   * bar under a node named foo.
+   *
+   * @param {Array} paths - an array of objects as
+   * returned by {parseXFAPath}.
+   * @param {number} pos - the current position in
+   * the paths array.
+   * @returns {SimpleDOMNode} The node corresponding
+   * to the path or null if not found.
+   */
+  searchNode(paths, pos) {
+    if (pos >= paths.length) {
+      return this;
+    }
+
+    const component = paths[pos];
+    const stack = [];
+    let node = this;
+
+    while (true) {
+      if (component.name === node.nodeName) {
+        if (component.pos === 0) {
+          const res = node.searchNode(paths, pos + 1);
+          if (res !== null) {
+            return res;
+          }
+        } else if (stack.length === 0) {
+          return null;
+        } else {
+          const [parent] = stack.pop();
+          let siblingPos = 0;
+          for (const child of parent.childNodes) {
+            if (component.name === child.nodeName) {
+              if (siblingPos === component.pos) {
+                return child.searchNode(paths, pos + 1);
+              }
+              siblingPos++;
+            }
+          }
+          // We didn't find the correct sibling
+          // so just return the first found node
+          return node.searchNode(paths, pos + 1);
+        }
+      }
+
+      if (node.childNodes && node.childNodes.length !== 0) {
+        stack.push([node, 0]);
+        node = node.childNodes[0];
+      } else if (stack.length === 0) {
+        return null;
+      } else {
+        while (stack.length !== 0) {
+          const [parent, currentPos] = stack.pop();
+          const newPos = currentPos + 1;
+          if (newPos < parent.childNodes.length) {
+            stack.push([parent, newPos]);
+            node = parent.childNodes[newPos];
+            break;
+          }
+        }
+        if (stack.length === 0) {
+          return null;
+        }
+      }
+    }
+  }
+
+  dump(buffer) {
+    if (this.nodeName === "#text") {
+      buffer.push(encodeToXmlString(this.nodeValue));
+      return;
+    }
+
+    buffer.push(`<${this.nodeName}`);
+    if (this.attributes) {
+      for (const attribute of this.attributes) {
+        buffer.push(
+          ` ${attribute.name}="${encodeToXmlString(attribute.value)}"`
+        );
+      }
+    }
+    if (this.hasChildNodes()) {
+      buffer.push(">");
+      for (const child of this.childNodes) {
+        child.dump(buffer);
+      }
+      buffer.push(`</${this.nodeName}>`);
+    } else if (this.nodeValue) {
+      buffer.push(`>${encodeToXmlString(this.nodeValue)}</${this.nodeName}>`);
+    } else {
+      buffer.push("/>");
+    }
+  }
+}
+
+class SimpleXMLParser extends XMLParserBase {
+  constructor({ hasAttributes = false, lowerCaseName = false }) {
+    super();
+    this._currentFragment = null;
+    this._stack = null;
+    this._errorCode = XMLParserErrorCode.NoError;
+    this._hasAttributes = hasAttributes;
+    this._lowerCaseName = lowerCaseName;
+  }
+
+  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;
+    if (!documentElement) {
+      return undefined; // Return undefined if no root was found.
+    }
+    return { documentElement };
+  }
+
+  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) {
+    if (this._lowerCaseName) {
+      name = name.toLowerCase();
+    }
+    const node = new SimpleDOMNode(name);
+    node.childNodes = [];
+    if (this._hasAttributes) {
+      node.attributes = attributes;
+    }
+    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];
+    if (!lastElement) {
+      return;
+    }
+    for (let i = 0, ii = lastElement.childNodes.length; i < ii; i++) {
+      lastElement.childNodes[i].parentNode = lastElement;
+    }
+  }
+
+  onError(code) {
+    this._errorCode = code;
+  }
+}
+
+export { SimpleDOMNode, SimpleXMLParser, XMLParserBase, XMLParserErrorCode };