tor-browser

large-pipeto.js (2831B)

---

const { AppConstants } = ChromeUtils.importESModule(
 "resource://gre/modules/AppConstants.sys.mjs"
);

// Stamp an array buffer with a pattern; verified by verify_chunk below.
function init(array) {
 for (var i = 0; i < array.length; i++) {
   array[i] = i % 256;
 }
}

// The construction of the file below ends up with 12 instances
// of the array buffer -- we want this to be larger than 2**32 bytes
// to exercise potential truncation of nsIInputStream::Read's count
// parameter.
const ABLENGTH = (2 ** 32 + 8) / 12;

// Get a large file (bigger than 2GB!)
function get_file() {
 const array = new ArrayBuffer(ABLENGTH);
 const buff = new Uint8Array(array);

 // Stamp with pattern.
 init(buff);

 const blob = new Blob([buff, buff], {});
 return new File([blob, blob, blob, blob, blob, blob], {});
}

// Verify that the chunks the stream recieve correspond to the initialization
function verify_chunk(chunk, verification_state) {
 for (var j = 0; j < chunk.length; j++) {
   // If we don't match the fill pattern.
   if (chunk[j] != verification_state.expected) {
     // we ran out of array buffer; so we should be looking at the first byte of the array again.
     if (
       verification_state.total_index % ABLENGTH != 0 ||
       chunk[j] != 0 /* ASSUME THAT THE INITIALIZATION OF THE BUFFER IS ZERO */
     ) {
       throw new Error(
         `Mismatch: chunk[${j}] (${chunk[j]}) != ${verification_state.expected} (total_index ${verification_state.total_index})`
       );
     }
     // Reset the fill expectation to 1 for next round.
     verification_state.expected = 1;
   } else {
     // We are inside regular fill section
     verification_state.expected = (verification_state.expected + 1) % 256;
   }
   verification_state.total_index++;
 }
}

// Pipe To Testing: Win32 can't handle the file size created in this test and OOMs.
add_task(
 {
   skip_if: () => AppConstants.platform == "win" && !Services.appinfo.is64Bit,
 },
 async () => {
   var chunk_verification_state = {
     expected: 0,
     total_index: 0,
   };

   const file = get_file();

   await file.stream().pipeTo(
     new WritableStream({
       write(chunk) {
         verify_chunk(chunk, chunk_verification_state);
       },
     })
   );
 }
);

// Do the same test as above, but this time don't use pipeTo.
add_task(
 {
   skip_if: () => AppConstants.platform == "win" && !Services.appinfo.is64Bit,
 },
 async () => {
   var file = get_file();

   var chunk_verification_state = {
     expected: 0,
     total_index: 0,
   };

   var streamReader = file.stream().getReader();

   while (true) {
     var res = await streamReader.read();
     if (res.done) {
       break;
     }
     var chunk = res.value;
     verify_chunk(chunk, chunk_verification_state);
   }
 }
);