Merge pull request #12060 from Snuffleupagus/evaluator-class

Convert the code in `src/core/evaluator.js` to use standard classes

src/core/evaluator.js

@@ -85,58 +85,20 @@ import { MurmurHash3_64 } from "./murmurhash3.js";
 import { OperatorList } from "./operator_list.js";
 import { PDFImage } from "./image.js";
 
-var PartialEvaluator = (function PartialEvaluatorClosure() {
+const DefaultPartialEvaluatorOptions = Object.freeze({
-  const DefaultPartialEvaluatorOptions = {
   maxImageSize: -1,
   disableFontFace: false,
   ignoreErrors: false,
   isEvalSupported: true,
   fontExtraProperties: false,
+});
+
+const PatternType = {
+  TILING: 1,
+  SHADING: 2,
 };
 
-  // eslint-disable-next-line no-shadow
+const deferred = Promise.resolve();
-  function PartialEvaluator({
-    xref,
-    handler,
-    pageIndex,
-    idFactory,
-    fontCache,
-    builtInCMapCache,
-    globalImageCache,
-    options = null,
-  }) {
-    this.xref = xref;
-    this.handler = handler;
-    this.pageIndex = pageIndex;
-    this.idFactory = idFactory;
-    this.fontCache = fontCache;
-    this.builtInCMapCache = builtInCMapCache;
-    this.globalImageCache = globalImageCache;
-    this.options = options || DefaultPartialEvaluatorOptions;
-    this.parsingType3Font = false;
-
-    this._fetchBuiltInCMapBound = this.fetchBuiltInCMap.bind(this);
-  }
-
-  // Trying to minimize Date.now() usage and check every 100 time
-  var TIME_SLOT_DURATION_MS = 20;
-  var CHECK_TIME_EVERY = 100;
-  function TimeSlotManager() {
-    this.reset();
-  }
-  TimeSlotManager.prototype = {
-    check: function TimeSlotManager_check() {
-      if (++this.checked < CHECK_TIME_EVERY) {
-        return false;
-      }
-      this.checked = 0;
-      return this.endTime <= Date.now();
-    },
-    reset: function TimeSlotManager_reset() {
-      this.endTime = Date.now() + TIME_SLOT_DURATION_MS;
-      this.checked = 0;
-    },
-  };
 
 // Convert PDF blend mode names to HTML5 blend mode names.
 function normalizeBlendMode(value, parsingArray = false) {
@@ -200,12 +162,58 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
   return "source-over";
 }
 
-  var deferred = Promise.resolve();
+// Trying to minimize Date.now() usage and check every 100 time.
+class TimeSlotManager {
+  static get TIME_SLOT_DURATION_MS() {
+    return shadow(this, "TIME_SLOT_DURATION_MS", 20);
+  }
 
-  var TILING_PATTERN = 1,
+  static get CHECK_TIME_EVERY() {
-    SHADING_PATTERN = 2;
+    return shadow(this, "CHECK_TIME_EVERY", 100);
+  }
+
+  constructor() {
+    this.reset();
+  }
+
+  check() {
+    if (++this.checked < TimeSlotManager.CHECK_TIME_EVERY) {
+      return false;
+    }
+    this.checked = 0;
+    return this.endTime <= Date.now();
+  }
+
+  reset() {
+    this.endTime = Date.now() + TimeSlotManager.TIME_SLOT_DURATION_MS;
+    this.checked = 0;
+  }
+}
+
+class PartialEvaluator {
+  constructor({
+    xref,
+    handler,
+    pageIndex,
+    idFactory,
+    fontCache,
+    builtInCMapCache,
+    globalImageCache,
+    options = null,
+  }) {
+    this.xref = xref;
+    this.handler = handler;
+    this.pageIndex = pageIndex;
+    this.idFactory = idFactory;
+    this.fontCache = fontCache;
+    this.builtInCMapCache = builtInCMapCache;
+    this.globalImageCache = globalImageCache;
+    this.options = options || DefaultPartialEvaluatorOptions;
+    this.parsingType3Font = false;
+
+    this._fetchBuiltInCMapBound = this.fetchBuiltInCMap.bind(this);
+  }
 
-  PartialEvaluator.prototype = {
   /**
    * Since Functions are only cached (locally) by reference, we can share one
    * `PDFFunctionFactory` instance within this `PartialEvaluator` instance.
@@ -216,15 +224,15 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       isEvalSupported: this.options.isEvalSupported,
     });
     return shadow(this, "_pdfFunctionFactory", pdfFunctionFactory);
-    },
+  }
 
   clone(newOptions = DefaultPartialEvaluatorOptions) {
     var newEvaluator = Object.create(this);
     newEvaluator.options = newOptions;
     return newEvaluator;
-    },
+  }
 
-    hasBlendModes: function PartialEvaluator_hasBlendModes(resources) {
+  hasBlendModes(resources) {
     if (!(resources instanceof Dict)) {
       return false;
     }
@@ -357,7 +365,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       }
     }
     return false;
-    },
+  }
 
   async fetchBuiltInCMap(name) {
     const cachedData = this.builtInCMapCache.get(name);
@@ -387,7 +395,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       this.builtInCMapCache.set(name, data);
     }
     return data;
-    },
+  }
 
   async buildFormXObject(
     resources,
@@ -464,7 +472,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
         operatorList.addOp(OPS.endGroup, [groupOptions]);
       }
     });
-    },
+  }
 
   _sendImgData(objId, imgData, cacheGlobally = false) {
     const transfers = imgData ? [imgData.data.buffer] : null;
@@ -488,7 +496,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       [objId, this.pageIndex, "Image", imgData],
       transfers
     );
-    },
+  }
 
   async buildPaintImageXObject({
     resources,
@@ -642,9 +650,9 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       }
     }
     return undefined;
-    },
+  }
 
-    handleSMask: function PartialEvaluator_handleSmask(
+  handleSMask(
     smask,
     resources,
     operatorList,
@@ -682,7 +690,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       stateManager.state.clone(),
       localColorSpaceCache
     );
-    },
+  }
 
   handleTilingType(
     fn,
@@ -739,16 +747,9 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
           throw reason;
         }
       );
-    },
+  }
 
-    handleSetFont: function PartialEvaluator_handleSetFont(
+  handleSetFont(resources, fontArgs, fontRef, operatorList, task, state) {
-      resources,
-      fontArgs,
-      fontRef,
-      operatorList,
-      task,
-      state
-    ) {
     // TODO(mack): Not needed?
     var fontName;
     if (fontArgs) {
@@ -785,7 +786,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
         translated.send(this.handler);
         return translated.loadedName;
       });
-    },
+  }
 
   handleText(chars, state) {
     const font = state.font;
@@ -805,7 +806,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       }
     }
     return glyphs;
-    },
+  }
 
   ensureStateFont(state) {
     if (state.font) {
@@ -825,9 +826,9 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       return;
     }
     throw reason;
-    },
+  }
 
-    setGState: function PartialEvaluator_setGState(
+  setGState(
     resources,
     gState,
     operatorList,
@@ -925,9 +926,9 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
         operatorList.addOp(OPS.setGState, [gStateObj]);
       }
     });
-    },
+  }
 
-    loadFont: function PartialEvaluator_loadFont(fontName, font, resources) {
+  loadFont(fontName, font, resources) {
     const errorFont = () => {
       return Promise.resolve(
         new TranslatedFont({
@@ -971,7 +972,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
 
       // Falling back to a default font to avoid completely broken rendering,
       // but note that there're no guarantees that things will look "correct".
-        fontRef = PartialEvaluator.getFallbackFontDict();
+      fontRef = PartialEvaluator.fallbackFontDict;
     }
 
     if (this.fontCache.has(fontRef)) {
@@ -1008,11 +1009,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
 
       if (fontAliases[hash]) {
         var aliasFontRef = fontAliases[hash].aliasRef;
-          if (
+        if (fontRefIsRef && aliasFontRef && this.fontCache.has(aliasFontRef)) {
-            fontRefIsRef &&
-            aliasFontRef &&
-            this.fontCache.has(aliasFontRef)
-          ) {
           this.fontCache.putAlias(fontRef, aliasFontRef);
           return this.fontCache.get(fontRef);
         }
@@ -1116,7 +1113,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
         );
       });
     return fontCapability.promise;
-    },
+  }
 
   buildPath(operatorList, fn, args, parsingText = false) {
     var lastIndex = operatorList.length - 1;
@@ -1149,7 +1146,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       opArgs[0].push(fn);
       Array.prototype.push.apply(opArgs[1], args);
     }
-    },
+  }
 
   parseColorSpace({ cs, resources, localColorSpaceCache }) {
     return ColorSpace.parseAsync({
@@ -1173,7 +1170,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       }
       throw reason;
     });
-    },
+  }
 
   async handleColorN(
     operatorList,
@@ -1193,7 +1190,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       var dict = isStream(pattern) ? pattern.dict : pattern;
       var typeNum = dict.get("PatternType");
 
-        if (typeNum === TILING_PATTERN) {
+      if (typeNum === PatternType.TILING) {
         var color = cs.base ? cs.base.getRgb(args, 0) : null;
         return this.handleTilingType(
           fn,
@@ -1204,7 +1201,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
           operatorList,
           task
         );
-        } else if (typeNum === SHADING_PATTERN) {
+      } else if (typeNum === PatternType.SHADING) {
         var shading = dict.get("Shading");
         var matrix = dict.getArray("Matrix");
         pattern = Pattern.parseShading(
@@ -1222,7 +1219,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       throw new FormatError(`Unknown PatternType: ${typeNum}`);
     }
     throw new FormatError(`Unknown PatternName: ${patternName}`);
-    },
+  }
 
   getOperatorList({
     stream,
@@ -1303,9 +1300,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
             next(
               new Promise(function (resolveXObject, rejectXObject) {
                 if (!name) {
-                    throw new FormatError(
+                  throw new FormatError("XObject must be referred to by name.");
-                      "XObject must be referred to by name."
-                    );
                 }
 
                 let xobj = xobjs.getRaw(name);
@@ -1748,7 +1743,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       }
       throw reason;
     });
-    },
+  }
 
   getTextContent({
     stream,
@@ -1870,8 +1865,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
         textContentItem.spaceWidth = spaceWidth;
         textContentItem.fakeSpaceMin = spaceWidth * SPACE_FACTOR;
         textContentItem.fakeMultiSpaceMin = spaceWidth * MULTI_SPACE_FACTOR;
-          textContentItem.fakeMultiSpaceMax =
+        textContentItem.fakeMultiSpaceMax = spaceWidth * MULTI_SPACE_FACTOR_MAX;
-            spaceWidth * MULTI_SPACE_FACTOR_MAX;
         // It's okay for monospace fonts to fake as much space as needed.
         textContentItem.textRunBreakAllowed = !font.isMonospace;
       } else {
@@ -2141,10 +2135,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
               advance.value > 0 &&
               advance.value <= textContentItem.fakeMultiSpaceMax
             ) {
-                textState.translateTextLineMatrix(
+              textState.translateTextLineMatrix(advance.width, advance.height);
-                  advance.width,
-                  advance.height
-                );
               textContentItem.width +=
                 advance.width - textContentItem.lastAdvanceWidth;
               textContentItem.height +=
@@ -2280,9 +2271,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
             next(
               new Promise(function (resolveXObject, rejectXObject) {
                 if (!name) {
-                    throw new FormatError(
+                  throw new FormatError("XObject must be referred to by name.");
-                      "XObject must be referred to by name."
-                    );
                 }
 
                 let xobj = xobjs.getRaw(name);
@@ -2430,13 +2419,9 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       }
       throw reason;
     });
-    },
+  }
 
-    extractDataStructures: function PartialEvaluator_extractDataStructures(
+  extractDataStructures(dict, baseDict, properties) {
-      dict,
-      baseDict,
-      properties
-    ) {
     const xref = this.xref;
     let cidToGidBytes;
     // 9.10.2
@@ -2557,7 +2542,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
         }
         return properties;
       });
-    },
+  }
 
   /**
    * @returns {ToUnicodeMap}
@@ -2658,7 +2643,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       toUnicode[charcode] = String.fromCharCode(glyphsUnicodeMap[glyphName]);
     }
     return new ToUnicodeMap(toUnicode);
-    },
+  }
 
   /**
    * Builds a char code to unicode map based on section 9.10 of the spec.
@@ -2749,9 +2734,9 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
     return Promise.resolve(
       new IdentityToUnicodeMap(properties.firstChar, properties.lastChar)
     );
-    },
+  }
 
-    readToUnicode: function PartialEvaluator_readToUnicode(toUnicode) {
+  readToUnicode(toUnicode) {
     var cmapObj = toUnicode;
     if (isName(cmapObj)) {
       return CMapFactory.create({
@@ -2813,7 +2798,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       );
     }
     return Promise.resolve(null);
-    },
+  }
 
   readCidToGidMap(glyphsData, toUnicode) {
     // Extract the encoding from the CIDToGIDMap
@@ -2829,13 +2814,9 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       result[code] = glyphID;
     }
     return result;
-    },
+  }
 
-    extractWidths: function PartialEvaluator_extractWidths(
+  extractWidths(dict, descriptor, properties) {
-      dict,
-      descriptor,
-      properties
-    ) {
     var xref = this.xref;
     var glyphsWidths = [];
     var defaultWidth = 0;
@@ -2907,10 +2888,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
         if (isName(baseFontName)) {
           var metrics = this.getBaseFontMetrics(baseFontName.name);
 
-            glyphsWidths = this.buildCharCodeToWidth(
+          glyphsWidths = this.buildCharCodeToWidth(metrics.widths, properties);
-              metrics.widths,
-              properties
-            );
           defaultWidth = metrics.defaultWidth;
         }
       }
@@ -2941,18 +2919,18 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
     properties.widths = glyphsWidths;
     properties.defaultVMetrics = defaultVMetrics;
     properties.vmetrics = glyphsVMetrics;
-    },
+  }
 
-    isSerifFont: function PartialEvaluator_isSerifFont(baseFontName) {
+  isSerifFont(baseFontName) {
     // Simulating descriptor flags attribute
     var fontNameWoStyle = baseFontName.split("-")[0];
     return (
       fontNameWoStyle in getSerifFonts() ||
       fontNameWoStyle.search(/serif/gi) !== -1
     );
-    },
+  }
 
-    getBaseFontMetrics: function PartialEvaluator_getBaseFontMetrics(name) {
+  getBaseFontMetrics(name) {
     var defaultWidth = 0;
     var widths = [];
     var monospace = false;
@@ -2983,20 +2961,14 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       monospace,
       widths,
     };
-    },
+  }
 
-    buildCharCodeToWidth: function PartialEvaluator_bulildCharCodeToWidth(
+  buildCharCodeToWidth(widthsByGlyphName, properties) {
-      widthsByGlyphName,
-      properties
-    ) {
     var widths = Object.create(null);
     var differences = properties.differences;
     var encoding = properties.defaultEncoding;
     for (var charCode = 0; charCode < 256; charCode++) {
-        if (
+      if (charCode in differences && widthsByGlyphName[differences[charCode]]) {
-          charCode in differences &&
-          widthsByGlyphName[differences[charCode]]
-        ) {
         widths[charCode] = widthsByGlyphName[differences[charCode]];
         continue;
       }
@@ -3006,9 +2978,9 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       }
     }
     return widths;
-    },
+  }
 
-    preEvaluateFont: function PartialEvaluator_preEvaluateFont(dict) {
+  preEvaluateFont(dict) {
     var baseDict = dict;
     var type = dict.get("Subtype");
     if (!isName(type)) {
@@ -3103,9 +3075,9 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       type: type.name,
       hash: hash ? hash.hexdigest() : "",
     };
-    },
+  }
 
-    translateFont: function PartialEvaluator_translateFont(preEvaluatedFont) {
+  translateFont(preEvaluatedFont) {
     var baseDict = preEvaluatedFont.baseDict;
     var dict = preEvaluatedFont.dict;
     var composite = preEvaluatedFont.composite;
@@ -3202,11 +3174,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
         );
         // Workaround for cases where e.g. fontNameStr = 'Arial' and
         // baseFontStr = 'Arial,Bold' (needed when no font file is embedded).
-          if (
+        if (fontNameStr && baseFontStr && baseFontStr.startsWith(fontNameStr)) {
-            fontNameStr &&
-            baseFontStr &&
-            baseFontStr.startsWith(fontNameStr)
-          ) {
           fontName = baseFont;
         }
       }
@@ -3284,10 +3252,9 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
         }
         return new Font(fontName.name, fontFile, newProperties);
       });
-    },
+  }
-  };
 
-  PartialEvaluator.buildFontPaths = function (font, glyphs, handler) {
+  static buildFontPaths(font, glyphs, handler) {
     function buildPath(fontChar) {
       if (font.renderer.hasBuiltPath(fontChar)) {
         return;
@@ -3309,25 +3276,18 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
         buildPath(accent.fontChar);
       }
     }
-  };
-
-  // TODO: Change this to a `static` getter, using shadowing, once
-  //       `PartialEvaluator` is converted to a proper class.
-  PartialEvaluator.getFallbackFontDict = function () {
-    if (this._fallbackFontDict) {
-      return this._fallbackFontDict;
   }
+
+  static get fallbackFontDict() {
     const dict = new Dict();
     dict.set("BaseFont", Name.get("PDFJS-FallbackFont"));
     dict.set("Type", Name.get("FallbackType"));
     dict.set("Subtype", Name.get("FallbackType"));
     dict.set("Encoding", Name.get("WinAnsiEncoding"));
 
-    return (this._fallbackFontDict = dict);
+    return shadow(this, "fallbackFontDict", dict);
-  };
+  }
-
+}
-  return PartialEvaluator;
-})();
 
 class TranslatedFont {
   constructor({ loadedName, font, dict, extraProperties = false }) {
@@ -3428,34 +3388,32 @@ class TranslatedFont {
   }
 }
 
-var StateManager = (function StateManagerClosure() {
+class StateManager {
-  // eslint-disable-next-line no-shadow
+  constructor(initialState) {
-  function StateManager(initialState) {
     this.state = initialState;
     this.stateStack = [];
   }
-  StateManager.prototype = {
+
   save() {
     var old = this.state;
     this.stateStack.push(this.state);
     this.state = old.clone();
-    },
+  }
+
   restore() {
     var prev = this.stateStack.pop();
     if (prev) {
       this.state = prev;
     }
-    },
+  }
+
   transform(args) {
     this.state.ctm = Util.transform(this.state.ctm, args);
-    },
+  }
-  };
+}
-  return StateManager;
-})();
 
-var TextState = (function TextStateClosure() {
+class TextState {
-  // eslint-disable-next-line no-shadow
+  constructor() {
-  function TextState() {
     this.ctm = new Float32Array(IDENTITY_MATRIX);
     this.fontName = null;
     this.fontSize = 0;
@@ -3470,8 +3428,7 @@ var TextState = (function TextStateClosure() {
     this.textRise = 0;
   }
 
-  TextState.prototype = {
+  setTextMatrix(a, b, c, d, e, f) {
-    setTextMatrix: function TextState_setTextMatrix(a, b, c, d, e, f) {
     var m = this.textMatrix;
     m[0] = a;
     m[1] = b;
@@ -3479,8 +3436,9 @@ var TextState = (function TextStateClosure() {
     m[3] = d;
     m[4] = e;
     m[5] = f;
-    },
+  }
-    setTextLineMatrix: function TextState_setTextMatrix(a, b, c, d, e, f) {
+
+  setTextLineMatrix(a, b, c, d, e, f) {
     var m = this.textLineMatrix;
     m[0] = a;
     m[1] = b;
@@ -3488,25 +3446,21 @@ var TextState = (function TextStateClosure() {
     m[3] = d;
     m[4] = e;
     m[5] = f;
-    },
+  }
-    translateTextMatrix: function TextState_translateTextMatrix(x, y) {
+
+  translateTextMatrix(x, y) {
     var m = this.textMatrix;
     m[4] = m[0] * x + m[2] * y + m[4];
     m[5] = m[1] * x + m[3] * y + m[5];
-    },
+  }
-    translateTextLineMatrix: function TextState_translateTextMatrix(x, y) {
+
+  translateTextLineMatrix(x, y) {
     var m = this.textLineMatrix;
     m[4] = m[0] * x + m[2] * y + m[4];
     m[5] = m[1] * x + m[3] * y + m[5];
-    },
+  }
-    calcTextLineMatrixAdvance: function TextState_calcTextLineMatrixAdvance(
+
-      a,
+  calcTextLineMatrixAdvance(a, b, c, d, e, f) {
-      b,
-      c,
-      d,
-      e,
-      f
-    ) {
     var font = this.font;
     if (!font) {
       return null;
@@ -3531,8 +3485,9 @@ var TextState = (function TextStateClosure() {
       ty = (-txDiff * b) / denominator;
     }
     return { width: tx, height: ty, value: font.vertical ? ty : tx };
-    },
+  }
-    calcRenderMatrix: function TextState_calcRendeMatrix(ctm) {
+
+  calcRenderMatrix(ctm) {
     // 9.4.4 Text Space Details
     var tsm = [
       this.fontSize * this.textHScale,
@@ -3543,45 +3498,43 @@ var TextState = (function TextStateClosure() {
       this.textRise,
     ];
     return Util.transform(ctm, Util.transform(this.textMatrix, tsm));
-    },
+  }
-    carriageReturn: function TextState_carriageReturn() {
+
+  carriageReturn() {
     this.translateTextLineMatrix(0, -this.leading);
     this.textMatrix = this.textLineMatrix.slice();
-    },
+  }
-    clone: function TextState_clone() {
+
+  clone() {
     var clone = Object.create(this);
     clone.textMatrix = this.textMatrix.slice();
     clone.textLineMatrix = this.textLineMatrix.slice();
     clone.fontMatrix = this.fontMatrix.slice();
     return clone;
-    },
+  }
-  };
+}
-  return TextState;
-})();
 
-var EvalState = (function EvalStateClosure() {
+class EvalState {
-  // eslint-disable-next-line no-shadow
+  constructor() {
-  function EvalState() {
     this.ctm = new Float32Array(IDENTITY_MATRIX);
     this.font = null;
     this.textRenderingMode = TextRenderingMode.FILL;
     this.fillColorSpace = ColorSpace.singletons.gray;
     this.strokeColorSpace = ColorSpace.singletons.gray;
   }
-  EvalState.prototype = {
-    clone: function CanvasExtraState_clone() {
-      return Object.create(this);
-    },
-  };
-  return EvalState;
-})();
 
-var EvaluatorPreprocessor = (function EvaluatorPreprocessorClosure() {
+  clone() {
+    return Object.create(this);
+  }
+}
+
+class EvaluatorPreprocessor {
+  static get opMap() {
     // Specifies properties for each command
     //
     // If variableArgs === true: [0, `numArgs`] expected
     // If variableArgs === false: exactly `numArgs` expected
-  var getOPMap = getLookupTableFactory(function (t) {
+    const getOPMap = getLookupTableFactory(function (t) {
       // Graphic state
       t.w = { id: OPS.setLineWidth, numArgs: 1, variableArgs: false };
       t.J = { id: OPS.setLineCap, numArgs: 1, variableArgs: false };
@@ -3700,15 +3653,18 @@ var EvaluatorPreprocessor = (function EvaluatorPreprocessorClosure() {
       t.null = null;
     });
 
-  const MAX_INVALID_PATH_OPS = 20;
+    return shadow(this, "opMap", getOPMap());
+  }
 
-  // eslint-disable-next-line no-shadow
+  static get MAX_INVALID_PATH_OPS() {
-  function EvaluatorPreprocessor(stream, xref, stateManager) {
+    return shadow(this, "MAX_INVALID_PATH_OPS", 20);
-    this.opMap = getOPMap();
+  }
+
+  constructor(stream, xref, stateManager) {
     // TODO(mduan): pass array of knownCommands rather than this.opMap
     // dictionary
     this.parser = new Parser({
-      lexer: new Lexer(stream, this.opMap),
+      lexer: new Lexer(stream, EvaluatorPreprocessor.opMap),
       xref,
     });
     this.stateManager = stateManager;
@@ -3716,10 +3672,9 @@ var EvaluatorPreprocessor = (function EvaluatorPreprocessorClosure() {
     this._numInvalidPathOPS = 0;
   }
 
-  EvaluatorPreprocessor.prototype = {
   get savedStatesDepth() {
     return this.stateManager.stateStack.length;
-    },
+  }
 
   // |operation| is an object with two fields:
   //
@@ -3742,14 +3697,14 @@ var EvaluatorPreprocessor = (function EvaluatorPreprocessorClosure() {
   // These two modes are present because this function is very hot and so
   // avoiding allocations where possible is worthwhile.
   //
-    read: function EvaluatorPreprocessor_read(operation) {
+  read(operation) {
     var args = operation.args;
     while (true) {
       var obj = this.parser.getObj();
       if (obj instanceof Cmd) {
         var cmd = obj.cmd;
         // Check that the command is valid
-          var opSpec = this.opMap[cmd];
+        var opSpec = EvaluatorPreprocessor.opMap[cmd];
         if (!opSpec) {
           warn(`Unknown command "${cmd}".`);
           continue;
@@ -3788,7 +3743,8 @@ var EvaluatorPreprocessor = (function EvaluatorPreprocessorClosure() {
             if (
               fn >= OPS.moveTo &&
               fn <= OPS.endPath && // Path operator
-                ++this._numInvalidPathOPS > MAX_INVALID_PATH_OPS
+              ++this._numInvalidPathOPS >
+                EvaluatorPreprocessor.MAX_INVALID_PATH_OPS
             ) {
               throw new FormatError(`Invalid ${partialMsg}`);
             }
@@ -3828,12 +3784,9 @@ var EvaluatorPreprocessor = (function EvaluatorPreprocessorClosure() {
         }
       }
     }
-    },
+  }
 
-    preprocessCommand: function EvaluatorPreprocessor_preprocessCommand(
+  preprocessCommand(fn, args) {
-      fn,
-      args
-    ) {
     switch (fn | 0) {
       case OPS.save:
         this.stateManager.save();
@@ -3845,9 +3798,7 @@ var EvaluatorPreprocessor = (function EvaluatorPreprocessorClosure() {
         this.stateManager.transform(args);
         break;
     }
-    },
+  }
-  };
+}
-  return EvaluatorPreprocessor;
-})();
 
 export { PartialEvaluator };