Compress the data when saving annotions

CompressionStream API has been added in Firefox 113
(see https://bugzilla.mozilla.org/show_bug.cgi?id=1823619)
hence we can use it to compress the streams with added/modified
annotations.

test/pdfs/.gitignore

@@ -590,3 +590,4 @@
 !copy_paste_ligatures.pdf
 !issue16316.pdf
 !issue14565.pdf
+!multiline.pdf

test/test_manifest.json

@@ -7580,5 +7580,19 @@
       "rounds": 1,
       "annotations": true,
       "type": "eq"
+   },
+   {
+      "id": "multiline_compress",
+      "file": "pdfs/multiline.pdf",
+      "md5": "4727c7d1e4e5c7d45fded8ab7a2e05e5",
+      "rounds": 1,
+      "type": "eq",
+      "save": true,
+      "print": true,
+      "annotationStorage": {
+         "24R": {
+            "value": "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\nabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\nabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\nabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\nabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\nabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\nabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\nabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\nabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\nabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\nabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\nabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\nabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\nabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\nabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\nabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\nabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz\nabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz"
+         }
+      }
    }
 ]

test/unit/annotation_spec.js

@@ -2115,6 +2115,58 @@ describe("annotation", function () {
       );
     });
 
+    it("should compress and save text", async function () {
+      const textWidgetRef = Ref.get(123, 0);
+      const xref = new XRefMock([
+        { ref: textWidgetRef, data: textWidgetDict },
+        helvRefObj,
+      ]);
+      partialEvaluator.xref = xref;
+      const task = new WorkerTask("test save");
+
+      const annotation = await AnnotationFactory.create(
+        xref,
+        textWidgetRef,
+        pdfManagerMock,
+        idFactoryMock
+      );
+      const annotationStorage = new Map();
+      const value = "a".repeat(256);
+      annotationStorage.set(annotation.data.id, { value });
+
+      const data = await annotation.save(
+        partialEvaluator,
+        task,
+        annotationStorage
+      );
+      expect(data.length).toEqual(2);
+      const [oldData, newData] = data;
+      expect(oldData.ref).toEqual(Ref.get(123, 0));
+      expect(newData.ref).toEqual(Ref.get(2, 0));
+
+      oldData.data = oldData.data.replace(/\(D:\d+\)/, "(date)");
+      expect(oldData.data).toEqual(
+        "123 0 obj\n" +
+          "<< /Type /Annot /Subtype /Widget /FT /Tx /DA (/Helv 5 Tf) /DR " +
+          "<< /Font << /Helv 314 0 R>>>> /Rect [0 0 32 10] " +
+          `/V (${value}) /AP << /N 2 0 R>> /M (date)>>\nendobj\n`
+      );
+
+      const compressedData = [
+        120, 156, 211, 15, 169, 80, 112, 242, 117, 86, 40, 84, 112, 10, 81, 208,
+        247, 72, 205, 41, 83, 48, 85, 8, 73, 83, 48, 84, 48, 0, 66, 8, 25, 146,
+        171, 96, 164, 96, 172, 103, 96, 174, 16, 146, 162, 160, 145, 56, 194,
+        129, 166, 66, 72, 150, 130, 107, 136, 66, 160, 130, 171, 175, 51, 0,
+        222, 235, 111, 133,
+      ];
+      const compressedStream = String.fromCharCode(...compressedData);
+      expect(newData.data).toEqual(
+        "2 0 obj\n<< /Subtype /Form /Resources " +
+          "<< /Font << /Helv 314 0 R>>>> /BBox [0 0 32 10] /Filter /FlateDecode /Length 68>> stream\n" +
+          `${compressedStream}\nendstream\nendobj\n`
+      );
+    });
+
     it("should get field object for usage in JS sandbox", async function () {
       const textWidgetRef = Ref.get(123, 0);
       const xDictRef = Ref.get(141, 0);

test/unit/writer_spec.js

@@ -20,7 +20,7 @@ import { StringStream } from "../../src/core/stream.js";
 
 describe("Writer", function () {
   describe("Incremental update", function () {
-    it("should update a file with new objects", function () {
+    it("should update a file with new objects", async function () {
       const originalData = new Uint8Array();
       const newRefs = [
         { ref: Ref.get(123, 0x2d), data: "abc\n" },
@@ -37,7 +37,7 @@ describe("Writer", function () {
         info: {},
       };
 
-      let data = incrementalUpdate({ originalData, xrefInfo, newRefs });
+      let data = await incrementalUpdate({ originalData, xrefInfo, newRefs });
       data = bytesToString(data);
 
       const expected =
@@ -60,7 +60,7 @@ describe("Writer", function () {
       expect(data).toEqual(expected);
     });
 
-    it("should update a file, missing the /ID-entry, with new objects", function () {
+    it("should update a file, missing the /ID-entry, with new objects", async function () {
       const originalData = new Uint8Array();
       const newRefs = [{ ref: Ref.get(123, 0x2d), data: "abc\n" }];
       const xrefInfo = {
@@ -74,7 +74,7 @@ describe("Writer", function () {
         info: {},
       };
 
-      let data = incrementalUpdate({ originalData, xrefInfo, newRefs });
+      let data = await incrementalUpdate({ originalData, xrefInfo, newRefs });
       data = bytesToString(data);
 
       const expected =
@@ -96,7 +96,7 @@ describe("Writer", function () {
   });
 
   describe("writeDict", function () {
-    it("should write a Dict", function () {
+    it("should write a Dict", async function () {
       const dict = new Dict(null);
       dict.set("A", Name.get("B"));
       dict.set("B", Ref.get(123, 456));
@@ -121,7 +121,7 @@ describe("Writer", function () {
       dict.set("NullVal", null);
 
       const buffer = [];
-      writeDict(dict, buffer, null);
+      await writeDict(dict, buffer, null);
 
       const expected =
         "<< /A /B /B 123 456 R /C 789 /D (hello world) " +
@@ -134,14 +134,14 @@ describe("Writer", function () {
       expect(buffer.join("")).toEqual(expected);
     });
 
-    it("should write a Dict in escaping PDF names", function () {
+    it("should write a Dict in escaping PDF names", async function () {
       const dict = new Dict(null);
       dict.set("\xfeA#", Name.get("hello"));
       dict.set("B", Name.get("#hello"));
       dict.set("C", Name.get("he\xfello\xff"));
 
       const buffer = [];
-      writeDict(dict, buffer, null);
+      await writeDict(dict, buffer, null);
 
       const expected = "<< /#feA#23 /hello /B /#23hello /C /he#fello#ff>>";
 
@@ -150,7 +150,7 @@ describe("Writer", function () {
   });
 
   describe("XFA", function () {
-    it("should update AcroForm when no datasets in XFA array", function () {
+    it("should update AcroForm when no datasets in XFA array", async function () {
       const originalData = new Uint8Array();
       const newRefs = [];
 
@@ -176,7 +176,7 @@ describe("Writer", function () {
         info: {},
       };
 
-      let data = incrementalUpdate({
+      let data = await incrementalUpdate({
         originalData,
         xrefInfo,
         newRefs,