Function TestImmutableBuffer

deps/v8/test/mjsunit/immutable-arraybuffer.js:7–68

(createSourceBuffer, description)

// Flags: --js-immutable-arraybuffer --allow-natives-syntax

function TestImmutableBuffer(createSourceBuffer, description) {
  const ab = createSourceBuffer();
  const immutable = ab.transferToImmutable();

  assertTrue(immutable.immutable);
  assertEquals(10, immutable.byteLength);
  assertFalse(immutable.resizable, "Immutable buffer should not be resizable");
  assertEquals(immutable.byteLength, immutable.maxByteLength, "Immutable buffer maxByteLength should equal byteLength");

  // 1. Test Detach throws
  assertThrows(() => %ArrayBufferDetach(immutable), TypeError);

  // 2. Test transfer throws
  assertThrows(() => immutable.transfer(), TypeError);

  // 3. Test resize throws
  assertThrows(() => immutable.resize(20), TypeError);

  // 4. Test slice works (should return a new mutable buffer by default)
  const sliced = immutable.slice(0, 5);
  assertFalse(sliced.immutable);
  assertEquals(5, sliced.byteLength);

  // 5. Test sliceToImmutable works
  const slicedImmutable = immutable.sliceToImmutable(0, 5);
  assertTrue(slicedImmutable.immutable);
  assertEquals(5, slicedImmutable.byteLength);

  // 6. Test DataView set throws
  const dv = new DataView(immutable);
  assertThrows(() => dv.setUint8(0, 1), TypeError);
  assertThrows(() => dv.setUint8(0, 255), TypeError);
  assertThrows(() => dv.setInt8(0, -1), TypeError);
  assertThrows(() => dv.setUint16(0, 0x1234), TypeError);
  assertThrows(() => dv.setFloat64(0, 3.14), TypeError);
  // 7. Test TypedArray set throws
  const ta = new Uint8Array(immutable);

  // Sloppy mode assignment - silent failure
  ta[0] = 1;
  ta[0] = 1;
  assertEquals(0, ta[0]); // Value should not change

  // Strict mode assignment - throws TypeError
  assertThrows(() => {
    "use strict";
    ta[0] = 1;
  }, TypeError);

  assertThrows(() => ta.set([1]), TypeError);
  assertThrows(() => ta.fill(1), TypeError);

  // 8. Test TypedArray.from/of with immutable buffer not directly applicable unless we construct one manually
  // but we can test constructing a TypedArray from immutable buffer (Read-only) matches values
  assertEquals(0, ta[0]);

  // 9. Test property descriptors of TypedArray backed by immutable buffer
  const desc = Object.getOwnPropertyDescriptor(ta, 0);