Convert the PDFDocument class in src/core/document.js to ES6 syntax

src/core/chunked_stream.js

@@ -12,6 +12,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+/* eslint no-var: error */
 
 import {
   arrayByteLength, arraysToBytes, createPromiseCapability, isEmptyObj,

src/core/document.js

@@ -12,6 +12,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+/* eslint no-var: error */
 
 import {
   assert, FormatError, getInheritableProperty, info, isArrayBuffer, isBool,
@@ -329,20 +330,41 @@ class Page {
   }
 }
 
-/**
+const FINGERPRINT_FIRST_BYTES = 1024;
- * The `PDFDocument` holds all the data of the PDF file. Compared to the
+const EMPTY_FINGERPRINT = '\x00\x00\x00\x00\x00\x00\x00' +
- * `PDFDoc`, this one doesn't have any job management code.
- * Right now there exists one PDFDocument on the main thread + one object
- * for each worker. If there is no worker support enabled, there are two
- * `PDFDocument` objects on the main thread created.
- */
-var PDFDocument = (function PDFDocumentClosure() {
-  var FINGERPRINT_FIRST_BYTES = 1024;
-  var EMPTY_FINGERPRINT = '\x00\x00\x00\x00\x00\x00\x00' +
                           '\x00\x00\x00\x00\x00\x00\x00\x00\x00';
 
-  function PDFDocument(pdfManager, arg) {
+function find(stream, needle, limit, backwards) {
-    var stream;
+  const pos = stream.pos;
+  const end = stream.end;
+  if (pos + limit > end) {
+    limit = end - pos;
+  }
+
+  const strBuf = [];
+  for (let i = 0; i < limit; ++i) {
+    strBuf.push(String.fromCharCode(stream.getByte()));
+  }
+  const str = strBuf.join('');
+
+  stream.pos = pos;
+  const index = backwards ? str.lastIndexOf(needle) : str.indexOf(needle);
+  if (index === -1) {
+    return false;
+  }
+  stream.pos += index;
+  return true;
+}
+
+/**
+ * The `PDFDocument` class holds all the data of the PDF file. There exists
+ * one `PDFDocument` object on the main thread and one object for each worker.
+ * If no worker support is enabled, two `PDFDocument` objects are created on
+ * the main thread.
+ */
+class PDFDocument {
+  constructor(pdfManager, arg) {
+    let stream;
     if (isStream(arg)) {
       stream = arg;
     } else if (isArrayBuffer(arg)) {
@@ -351,41 +373,150 @@ var PDFDocument = (function PDFDocumentClosure() {
       throw new Error('PDFDocument: Unknown argument type');
     }
     if (stream.length <= 0) {
-      throw new Error('PDFDocument: stream must have data');
+      throw new Error('PDFDocument: Stream must have data');
     }
 
     this.pdfManager = pdfManager;
     this.stream = stream;
     this.xref = new XRef(stream, pdfManager);
 
-    let evaluatorOptions = pdfManager.evaluatorOptions;
     this.pdfFunctionFactory = new PDFFunctionFactory({
       xref: this.xref,
-      isEvalSupported: evaluatorOptions.isEvalSupported,
+      isEvalSupported: pdfManager.evaluatorOptions.isEvalSupported,
     });
     this._pagePromises = [];
   }
 
-  function find(stream, needle, limit, backwards) {
+  parse(recoveryMode) {
-    var pos = stream.pos;
+    this.setup(recoveryMode);
-    var end = stream.end;
+
-    var strBuf = [];
+    const version = this.catalog.catDict.get('Version');
-    if (pos + limit > end) {
+    if (isName(version)) {
-      limit = end - pos;
+      this.pdfFormatVersion = version.name;
-    }
-    for (var n = 0; n < limit; ++n) {
-      strBuf.push(String.fromCharCode(stream.getByte()));
-    }
-    var str = strBuf.join('');
-    stream.pos = pos;
-    var index = backwards ? str.lastIndexOf(needle) : str.indexOf(needle);
-    if (index === -1) {
-      return false; /* not found */
-    }
-    stream.pos += index;
-    return true; /* found */
     }
 
+    // Check if AcroForms are present in the document.
+    try {
+      this.acroForm = this.catalog.catDict.get('AcroForm');
+      if (this.acroForm) {
+        this.xfa = this.acroForm.get('XFA');
+        const fields = this.acroForm.get('Fields');
+        if ((!fields || !Array.isArray(fields) || fields.length === 0) &&
+            !this.xfa) {
+          this.acroForm = null; // No fields and no XFA, so it's not a form.
+        }
+      }
+    } catch (ex) {
+      if (ex instanceof MissingDataException) {
+        throw ex;
+      }
+      info('Cannot fetch AcroForm entry; assuming no AcroForms are present');
+      this.acroForm = null;
+    }
+  }
+
+  get linearization() {
+    let linearization = null;
+    try {
+      linearization = Linearization.create(this.stream);
+    } catch (err) {
+      if (err instanceof MissingDataException) {
+        throw err;
+      }
+      info(err);
+    }
+    return shadow(this, 'linearization', linearization);
+  }
+
+  get startXRef() {
+    const stream = this.stream;
+    let startXRef = 0;
+
+    if (this.linearization) {
+      // Find the end of the first object.
+      stream.reset();
+      if (find(stream, 'endobj', 1024)) {
+        startXRef = stream.pos + 6;
+      }
+    } else {
+      // Find `startxref` by checking backwards from the end of the file.
+      const step = 1024;
+      const startXRefLength = 'startxref'.length;
+      let found = false, pos = stream.end;
+
+      while (!found && pos > 0) {
+        pos -= step - startXRefLength;
+        if (pos < 0) {
+          pos = 0;
+        }
+        stream.pos = pos;
+        found = find(stream, 'startxref', step, true);
+      }
+
+      if (found) {
+        stream.skip(9);
+        let ch;
+        do {
+          ch = stream.getByte();
+        } while (isSpace(ch));
+        let str = '';
+        while (ch >= 0x20 && ch <= 0x39) { // < '9'
+          str += String.fromCharCode(ch);
+          ch = stream.getByte();
+        }
+        startXRef = parseInt(str, 10);
+        if (isNaN(startXRef)) {
+          startXRef = 0;
+        }
+      }
+    }
+    return shadow(this, 'startXRef', startXRef);
+  }
+
+  // Find the header, get the PDF format version and setup the
+  // stream to start from the header.
+  checkHeader() {
+    const stream = this.stream;
+    stream.reset();
+
+    if (!find(stream, '%PDF-', 1024)) {
+      // May not be a PDF file, but don't throw an error and let
+      // parsing continue.
+      return;
+    }
+    stream.moveStart();
+
+    // Read the PDF format version.
+    const MAX_PDF_VERSION_LENGTH = 12;
+    let version = '', ch;
+    while ((ch = stream.getByte()) > 0x20) { // Space
+      if (version.length >= MAX_PDF_VERSION_LENGTH) {
+        break;
+      }
+      version += String.fromCharCode(ch);
+    }
+    if (!this.pdfFormatVersion) {
+      // Remove the "%PDF-" prefix.
+      this.pdfFormatVersion = version.substring(5);
+    }
+  }
+
+  parseStartXRef() {
+    this.xref.setStartXRef(this.startXRef);
+  }
+
+  setup(recoveryMode) {
+    this.xref.parse(recoveryMode);
+    this.catalog = new Catalog(this.pdfManager, this.xref);
+  }
+
+  get numPages() {
+    const linearization = this.linearization;
+    const num = linearization ? linearization.numPages : this.catalog.numPages;
+    return shadow(this, 'numPages', num);
+  }
+
+  get documentInfo() {
     const DocumentInfoValidators = {
       Title: isString,
       Author: isString,
@@ -398,136 +529,13 @@ var PDFDocument = (function PDFDocumentClosure() {
       Trapped: isName,
     };
 
-  PDFDocument.prototype = {
-    parse: function PDFDocument_parse(recoveryMode) {
-      this.setup(recoveryMode);
-      var version = this.catalog.catDict.get('Version');
-      if (isName(version)) {
-        this.pdfFormatVersion = version.name;
-      }
-      try {
-        // checking if AcroForm is present
-        this.acroForm = this.catalog.catDict.get('AcroForm');
-        if (this.acroForm) {
-          this.xfa = this.acroForm.get('XFA');
-          var fields = this.acroForm.get('Fields');
-          if ((!fields || !Array.isArray(fields) || fields.length === 0) &&
-              !this.xfa) {
-            // no fields and no XFA -- not a form (?)
-            this.acroForm = null;
-          }
-        }
-      } catch (ex) {
-        if (ex instanceof MissingDataException) {
-          throw ex;
-        }
-        info('Something wrong with AcroForm entry');
-        this.acroForm = null;
-      }
-    },
-
-    get linearization() {
-      let linearization = null;
-      try {
-        linearization = Linearization.create(this.stream);
-      } catch (err) {
-        if (err instanceof MissingDataException) {
-          throw err;
-        }
-        info(err);
-      }
-      // shadow the prototype getter with a data property
-      return shadow(this, 'linearization', linearization);
-    },
-    get startXRef() {
-      var stream = this.stream;
-      var startXRef = 0;
-      var linearization = this.linearization;
-      if (linearization) {
-        // Find end of first obj.
-        stream.reset();
-        if (find(stream, 'endobj', 1024)) {
-          startXRef = stream.pos + 6;
-        }
-      } else {
-        // Find startxref by jumping backward from the end of the file.
-        var step = 1024;
-        var found = false, pos = stream.end;
-        while (!found && pos > 0) {
-          pos -= step - 'startxref'.length;
-          if (pos < 0) {
-            pos = 0;
-          }
-          stream.pos = pos;
-          found = find(stream, 'startxref', step, true);
-        }
-        if (found) {
-          stream.skip(9);
-          var ch;
-          do {
-            ch = stream.getByte();
-          } while (isSpace(ch));
-          var str = '';
-          while (ch >= 0x20 && ch <= 0x39) { // < '9'
-            str += String.fromCharCode(ch);
-            ch = stream.getByte();
-          }
-          startXRef = parseInt(str, 10);
-          if (isNaN(startXRef)) {
-            startXRef = 0;
-          }
-        }
-      }
-      // shadow the prototype getter with a data property
-      return shadow(this, 'startXRef', startXRef);
-    },
-
-    // Find the header, remove leading garbage and setup the stream
-    // starting from the header.
-    checkHeader: function PDFDocument_checkHeader() {
-      var stream = this.stream;
-      stream.reset();
-      if (find(stream, '%PDF-', 1024)) {
-        // Found the header, trim off any garbage before it.
-        stream.moveStart();
-        // Reading file format version
-        var MAX_VERSION_LENGTH = 12;
-        var version = '', ch;
-        while ((ch = stream.getByte()) > 0x20) { // SPACE
-          if (version.length >= MAX_VERSION_LENGTH) {
-            break;
-          }
-          version += String.fromCharCode(ch);
-        }
-        if (!this.pdfFormatVersion) {
-          // removing "%PDF-"-prefix
-          this.pdfFormatVersion = version.substring(5);
-        }
-        return;
-      }
-      // May not be a PDF file, continue anyway.
-    },
-    parseStartXRef: function PDFDocument_parseStartXRef() {
-      var startXRef = this.startXRef;
-      this.xref.setStartXRef(startXRef);
-    },
-    setup: function PDFDocument_setup(recoveryMode) {
-      this.xref.parse(recoveryMode);
-      this.catalog = new Catalog(this.pdfManager, this.xref);
-    },
-    get numPages() {
-      var linearization = this.linearization;
-      var num = linearization ? linearization.numPages : this.catalog.numPages;
-      // shadow the prototype getter
-      return shadow(this, 'numPages', num);
-    },
-    get documentInfo() {
     const docInfo = {
       PDFFormatVersion: this.pdfFormatVersion,
       IsLinearized: !!this.linearization,
       IsAcroFormPresent: !!this.acroForm,
       IsXFAPresent: !!this.xfa,
     };
+
     let infoDict;
     try {
       infoDict = this.xref.trailer.get('Info');
@@ -537,10 +545,11 @@ var PDFDocument = (function PDFDocumentClosure() {
       }
       info('The document information dictionary is invalid.');
     }
+
     if (isDict(infoDict)) {
       // Fill the document info with valid entries from the specification,
       // as well as any existing well-formed custom entries.
-        for (let key of infoDict.getKeys()) {
+      for (const key of infoDict.getKeys()) {
         const value = infoDict.get(key);
 
         if (DocumentInfoValidators[key]) {
@@ -573,11 +582,11 @@ var PDFDocument = (function PDFDocumentClosure() {
       }
     }
     return shadow(this, 'documentInfo', docInfo);
-    },
+  }
-    get fingerprint() {
-      var xref = this.xref, hash, fileID = '';
-      var idArray = xref.trailer.get('ID');
 
+  get fingerprint() {
+    let hash;
+    const idArray = this.xref.trailer.get('ID');
     if (Array.isArray(idArray) && idArray[0] && isString(idArray[0]) &&
         idArray[0] !== EMPTY_FINGERPRINT) {
       hash = stringToBytes(idArray[0]);
@@ -590,13 +599,13 @@ var PDFDocument = (function PDFDocumentClosure() {
         FINGERPRINT_FIRST_BYTES), 0, FINGERPRINT_FIRST_BYTES);
     }
 
-      for (var i = 0, n = hash.length; i < n; i++) {
+    let fingerprint = '';
-        var hex = hash[i].toString(16);
+    for (const hashPart of hash) {
-        fileID += hex.length === 1 ? '0' + hex : hex;
+      const hex = hashPart.toString(16);
+      fingerprint += (hex.length === 1 ? '0' + hex : hex);
+    }
+    return shadow(this, 'fingerprint', fingerprint);
   }
-
-      return shadow(this, 'fingerprint', fileID);
-    },
 
   _getLinearizationPage(pageIndex) {
     const { catalog, linearization, } = this;
@@ -618,7 +627,7 @@ var PDFDocument = (function PDFDocumentClosure() {
       info(reason);
       return catalog.getPageDict(pageIndex);
     });
-    },
+  }
 
   getPage(pageIndex) {
     if (this._pagePromises[pageIndex] !== undefined) {
@@ -641,7 +650,7 @@ var PDFDocument = (function PDFDocumentClosure() {
         pdfFunctionFactory: this.pdfFunctionFactory,
       });
     });
-    },
+  }
 
   checkFirstPage() {
     return this.getPage(0).catch((reason) => {
@@ -655,15 +664,12 @@ var PDFDocument = (function PDFDocumentClosure() {
         throw new XRefParseException();
       }
     });
-    },
+  }
 
-    cleanup: function PDFDocument_cleanup() {
+  cleanup() {
     return this.catalog.cleanup();
-    },
+  }
-  };
+}
-
-  return PDFDocument;
-})();
 
 export {
   Page,