Improve (local) caching of parsed ColorSpaces (PR 12001 follow-up)

This patch contains the following *notable* improvements:
 - Changes the `ColorSpace.parse` call-sites to, where possible, pass in a reference rather than actual ColorSpace data (necessary for the next point).
 - Adds (local) caching of `ColorSpace`s by `Ref`, when applicable, in addition the caching by name. This (generally) improves `ColorSpace` caching for e.g. the SMask code-paths.
 - Extends the (local) `ColorSpace` caching to also apply when handling Images and Patterns, thus further reducing unneeded re-parsing.
 - Adds a new `ColorSpace.parseAsync` method, almost identical to the existing `ColorSpace.parse` one, but returning a Promise instead (this simplifies some code in the `PartialEvaluator`).

test/unit/colorspace_spec.js

@@ -16,18 +16,21 @@
 import { Dict, Name, Ref } from "../../src/core/primitives.js";
 import { Stream, StringStream } from "../../src/core/stream.js";
 import { ColorSpace } from "../../src/core/colorspace.js";
+import { LocalColorSpaceCache } from "../../src/core/image_utils.js";
 import { PDFFunctionFactory } from "../../src/core/function.js";
 import { XRefMock } from "./test_utils.js";
 
 describe("colorspace", function () {
-  describe("ColorSpace", function () {
+  describe("ColorSpace.isDefaultDecode", function () {
     it("should be true if decode is not an array", function () {
       expect(ColorSpace.isDefaultDecode("string", 0)).toBeTruthy();
     });
+
     it("should be true if length of decode array is not correct", function () {
       expect(ColorSpace.isDefaultDecode([0], 1)).toBeTruthy();
       expect(ColorSpace.isDefaultDecode([0, 1, 0], 1)).toBeTruthy();
     });
+
     it("should be true if decode map matches the default decode map", function () {
       expect(ColorSpace.isDefaultDecode([], 0)).toBeTruthy();
 
@@ -46,6 +49,138 @@ describe("colorspace", function () {
     });
   });
 
+  describe("ColorSpace caching", function () {
+    let localColorSpaceCache = null;
+
+    beforeAll(function (done) {
+      localColorSpaceCache = new LocalColorSpaceCache();
+      done();
+    });
+
+    afterAll(function (done) {
+      localColorSpaceCache = null;
+      done();
+    });
+
+    it("caching by Name", function () {
+      const xref = new XRefMock();
+      const pdfFunctionFactory = new PDFFunctionFactory({
+        xref,
+      });
+
+      const colorSpace1 = ColorSpace.parse({
+        cs: Name.get("Pattern"),
+        xref,
+        resources: null,
+        pdfFunctionFactory,
+        localColorSpaceCache,
+      });
+      expect(colorSpace1.name).toEqual("Pattern");
+
+      const colorSpace2 = ColorSpace.parse({
+        cs: Name.get("Pattern"),
+        xref,
+        resources: null,
+        pdfFunctionFactory,
+        localColorSpaceCache,
+      });
+      expect(colorSpace2.name).toEqual("Pattern");
+
+      const colorSpaceNonCached = ColorSpace.parse({
+        cs: Name.get("Pattern"),
+        xref,
+        resources: null,
+        pdfFunctionFactory,
+        localColorSpaceCache: new LocalColorSpaceCache(),
+      });
+      expect(colorSpaceNonCached.name).toEqual("Pattern");
+
+      const colorSpaceOther = ColorSpace.parse({
+        cs: Name.get("RGB"),
+        xref,
+        resources: null,
+        pdfFunctionFactory,
+        localColorSpaceCache,
+      });
+      expect(colorSpaceOther.name).toEqual("DeviceRGB");
+
+      // These two must be *identical* if caching worked as intended.
+      expect(colorSpace1).toBe(colorSpace2);
+
+      expect(colorSpace1).not.toBe(colorSpaceNonCached);
+      expect(colorSpace1).not.toBe(colorSpaceOther);
+    });
+
+    it("caching by Ref", function () {
+      const paramsCalGray = new Dict();
+      paramsCalGray.set("WhitePoint", [1, 1, 1]);
+      paramsCalGray.set("BlackPoint", [0, 0, 0]);
+      paramsCalGray.set("Gamma", 2.0);
+
+      const paramsCalRGB = new Dict();
+      paramsCalRGB.set("WhitePoint", [1, 1, 1]);
+      paramsCalRGB.set("BlackPoint", [0, 0, 0]);
+      paramsCalRGB.set("Gamma", [1, 1, 1]);
+      paramsCalRGB.set("Matrix", [1, 0, 0, 0, 1, 0, 0, 0, 1]);
+
+      const xref = new XRefMock([
+        {
+          ref: Ref.get(50, 0),
+          data: [Name.get("CalGray"), paramsCalGray],
+        },
+        {
+          ref: Ref.get(100, 0),
+          data: [Name.get("CalRGB"), paramsCalRGB],
+        },
+      ]);
+      const pdfFunctionFactory = new PDFFunctionFactory({
+        xref,
+      });
+
+      const colorSpace1 = ColorSpace.parse({
+        cs: Ref.get(50, 0),
+        xref,
+        resources: null,
+        pdfFunctionFactory,
+        localColorSpaceCache,
+      });
+      expect(colorSpace1.name).toEqual("CalGray");
+
+      const colorSpace2 = ColorSpace.parse({
+        cs: Ref.get(50, 0),
+        xref,
+        resources: null,
+        pdfFunctionFactory,
+        localColorSpaceCache,
+      });
+      expect(colorSpace2.name).toEqual("CalGray");
+
+      const colorSpaceNonCached = ColorSpace.parse({
+        cs: Ref.get(50, 0),
+        xref,
+        resources: null,
+        pdfFunctionFactory,
+        localColorSpaceCache: new LocalColorSpaceCache(),
+      });
+      expect(colorSpaceNonCached.name).toEqual("CalGray");
+
+      const colorSpaceOther = ColorSpace.parse({
+        cs: Ref.get(100, 0),
+        xref,
+        resources: null,
+        pdfFunctionFactory,
+        localColorSpaceCache,
+      });
+      expect(colorSpaceOther.name).toEqual("CalRGB");
+
+      // These two must be *identical* if caching worked as intended.
+      expect(colorSpace1).toBe(colorSpace2);
+
+      expect(colorSpace1).not.toBe(colorSpaceNonCached);
+      expect(colorSpace1).not.toBe(colorSpaceOther);
+    });
+  });
+
   describe("DeviceGrayCS", function () {
     it("should handle the case when cs is a Name object", function () {
       const cs = Name.get("DeviceGray");
@@ -65,6 +200,7 @@ describe("colorspace", function () {
         xref,
         resources,
         pdfFunctionFactory,
+        localColorSpaceCache: new LocalColorSpaceCache(),
       });
 
       const testSrc = new Uint8Array([27, 125, 250, 131]);
@@ -115,6 +251,7 @@ describe("colorspace", function () {
         xref,
         resources,
         pdfFunctionFactory,
+        localColorSpaceCache: new LocalColorSpaceCache(),
       });
 
       const testSrc = new Uint8Array([27, 125, 250, 131]);
@@ -161,6 +298,7 @@ describe("colorspace", function () {
         xref,
         resources,
         pdfFunctionFactory,
+        localColorSpaceCache: new LocalColorSpaceCache(),
       });
 
       // prettier-ignore
@@ -217,6 +355,7 @@ describe("colorspace", function () {
         xref,
         resources,
         pdfFunctionFactory,
+        localColorSpaceCache: new LocalColorSpaceCache(),
       });
 
       // prettier-ignore
@@ -269,6 +408,7 @@ describe("colorspace", function () {
         xref,
         resources,
         pdfFunctionFactory,
+        localColorSpaceCache: new LocalColorSpaceCache(),
       });
 
       // prettier-ignore
@@ -325,6 +465,7 @@ describe("colorspace", function () {
         xref,
         resources,
         pdfFunctionFactory,
+        localColorSpaceCache: new LocalColorSpaceCache(),
       });
 
       // prettier-ignore
@@ -382,6 +523,7 @@ describe("colorspace", function () {
         xref,
         resources,
         pdfFunctionFactory,
+        localColorSpaceCache: new LocalColorSpaceCache(),
       });
 
       const testSrc = new Uint8Array([27, 125, 250, 131]);
@@ -441,6 +583,7 @@ describe("colorspace", function () {
         xref,
         resources,
         pdfFunctionFactory,
+        localColorSpaceCache: new LocalColorSpaceCache(),
       });
 
       // prettier-ignore
@@ -498,6 +641,7 @@ describe("colorspace", function () {
         xref,
         resources,
         pdfFunctionFactory,
+        localColorSpaceCache: new LocalColorSpaceCache(),
       });
 
       // prettier-ignore
@@ -557,6 +701,7 @@ describe("colorspace", function () {
         xref,
         resources,
         pdfFunctionFactory,
+        localColorSpaceCache: new LocalColorSpaceCache(),
       });
 
       const testSrc = new Uint8Array([2, 2, 0, 1]);
@@ -624,6 +769,7 @@ describe("colorspace", function () {
         xref,
         resources,
         pdfFunctionFactory,
+        localColorSpaceCache: new LocalColorSpaceCache(),
       });
 
       const testSrc = new Uint8Array([27, 25, 50, 31]);