fix: accept per-cabinet reserve metadata

src/onenote/onepkg/cabinet-set.test.ts

@@ -48,34 +48,39 @@ function mutateU16(
   return { ...part, bytes };
 }
 
-function withEmptyReserveLayout(part: CabSetPart): CabSetPart {
+function withDistinctFolderReserve(part: CabSetPart): CabSetPart {
   const original = part.bytes;
-  const insertAt = 36;
-  const addedBytes = 4;
+  const originalView = new DataView(
+    original.buffer,
+    original.byteOffset,
+    original.byteLength
+  );
+  const reserveHeaderOffset = 36;
+  const originalFileOffset = originalView.getUint32(16, true);
+  // The pinned fixture part has one zero-reserve CFFOLDER immediately before
+  // its CFFILE table. Add the optional reserve-size header plus one private
+  // folder-reserve byte without changing any compressed data.
+  const originalFolderOffset = originalFileOffset - 8;
+  const addedBytes = 5;
   const bytes = new Uint8Array(original.length + addedBytes);
-  bytes.set(original.subarray(0, insertAt));
-  bytes.set(original.subarray(insertAt), insertAt + addedBytes);
+  bytes.set(original.subarray(0, reserveHeaderOffset));
+  bytes.set(
+    original.subarray(reserveHeaderOffset, originalFileOffset),
+    reserveHeaderOffset + 4
+  );
+  bytes[originalFileOffset + 4] = 0xa5;
+  bytes.set(original.subarray(originalFileOffset), originalFileOffset + 5);
+
   const view = new DataView(bytes.buffer);
   view.setUint32(8, original.length + addedBytes, true);
+  view.setUint32(16, originalFileOffset + addedBytes, true);
+  view.setUint16(30, originalView.getUint16(30, true) | 0x0004, true);
+  view.setUint16(reserveHeaderOffset, 0, true);
+  view.setUint8(reserveHeaderOffset + 2, 1);
+  view.setUint8(reserveHeaderOffset + 3, 0);
   view.setUint32(
-    16,
-    new DataView(original.buffer, original.byteOffset).getUint32(16, true) +
-      addedBytes,
-    true
-  );
-  view.setUint16(
-    30,
-    new DataView(original.buffer, original.byteOffset).getUint16(30, true) |
-      0x0004,
-    true
-  );
-  // cbCFHeader, cbCFFolder, and cbCFData are all zero.
-  bytes.fill(0, insertAt, insertAt + addedBytes);
-  // This fixture's only CFFOLDER begins at 0x8e before insertion.
-  view.setUint32(
-    0x8e + addedBytes,
-    new DataView(original.buffer, original.byteOffset).getUint32(0x8e, true) +
-      addedBytes,
+    originalFolderOffset + 4,
+    originalView.getUint32(originalFolderOffset, true) + addedBytes,
     true
   );
   return { ...part, bytes };
@@ -167,12 +172,6 @@ describe('multi-cabinet sets', () => {
       diagnostic: { code: 'cab-set-file-continuation-mismatch' },
     });
 
-    const reserve = fixtureSet();
-    reserve[2] = withEmptyReserveLayout(reserve[2]!);
-    await expect(extractCabinetSet(reserve)).rejects.toMatchObject({
-      diagnostic: { code: 'cab-set-reserve-layout-mismatch' },
-    });
-
     const incompleteBlock = fixtureSet();
     // Part 5's last CFDATA cbUncomp is at 0xb5.
     incompleteBlock[4] = mutateU16(incompleteBlock[4]!, 0xb5, 0);
@@ -181,6 +180,23 @@ describe('multi-cabinet sets', () => {
     });
   });
 
+  it('accepts independent reserve layouts and folder metadata per part', async () => {
+    const parts = fixtureSet();
+    parts[2] = withDistinctFolderReserve(parts[2]!);
+
+    const result = await extractCabinetSet(parts);
+
+    expect(
+      result.extractedEntries.map((entry) =>
+        new TextDecoder().decode(entry.bytes)
+      )
+    ).toEqual([
+      expectedPart(1) + expectedPart(2),
+      expectedPart(3),
+      expectedPart(4) + expectedPart(5),
+    ]);
+  });
+
   it('opens the complete set through the package API', async () => {
     const parts = fixtureSet();
     const result = await openOneNotePackageSet(parts, {

src/onenote/onepkg/cabinet-set.ts

@@ -15,7 +15,6 @@ import {
   FOLDER_CONTINUED_FROM_PREVIOUS,
   FOLDER_CONTINUED_PREVIOUS_AND_NEXT,
   FOLDER_CONTINUED_TO_NEXT,
-  FLAG_RESERVE_PRESENT,
   parseCabinetInternal,
   verifyDataBlockChecksumInternal,
   type CabDataBlockInternal,
@@ -87,13 +86,6 @@ function checkedAdd(
   return sum;
 }
 
-function bytesEqual(left: Uint8Array, right: Uint8Array): boolean {
-  return (
-    left.length === right.length &&
-    left.every((value, index) => value === right[index])
-  );
-}
-
 function cabinetNameKey(value: string, structure: string): string {
   const normalized = value.normalize('NFC');
   if (
@@ -186,13 +178,6 @@ function validateBoundary(left: NamedCabinet, right: NamedCabinet): boolean {
       { structure: 'CFFOLDER.typeCompress' }
     );
   }
-  if (!bytesEqual(leftFolder.reserve, rightFolder.reserve)) {
-    fail(
-      'cab-set-folder-reserve-mismatch',
-      'Continued folder segments have different reserved metadata.',
-      { structure: 'CFFOLDER.abReserve' }
-    );
-  }
   return true;
 }
 
@@ -258,7 +243,6 @@ function validateNamedCabinets(
       left.parsed.result.cabinetSetIndex - right.parsed.result.cabinetSetIndex
   );
   const setId = cabinets[0]!.parsed.result.cabinetSetId;
-  const reserveTemplate = cabinets[0]!.parsed;
   for (let index = 0; index < cabinets.length; index += 1) {
     const cabinet = cabinets[index]!;
     const parsed = cabinet.parsed;
@@ -276,19 +260,6 @@ function validateNamedCabinets(
         { structure: 'CFHEADER.iCabinet' }
       );
     }
-    if (
-      (parsed.flags & FLAG_RESERVE_PRESENT) !==
-        (reserveTemplate.flags & FLAG_RESERVE_PRESENT) ||
-      parsed.headerReserveSize !== reserveTemplate.headerReserveSize ||
-      parsed.folderReserveSize !== reserveTemplate.folderReserveSize ||
-      parsed.dataReserveSize !== reserveTemplate.dataReserveSize
-    ) {
-      fail(
-        'cab-set-reserve-layout-mismatch',
-        'Cabinet parts use inconsistent reserve-area layouts.',
-        { structure: 'CFHEADER reserve sizes' }
-      );
-    }
   }
 
   for (let index = 0; index < cabinets.length; index += 1) {