// META: title=FileReader: starting new reads while one is in progress

test(function() {
  var blob_1 = new Blob(['TEST000000001'])
  var blob_2 = new Blob(['TEST000000002'])
  var reader = new FileReader();
  reader.readAsText(blob_1)
  assert_equals(reader.readyState, FileReader.LOADING, "readyState Must be LOADING")
  assert_throws_dom("InvalidStateError", function () {
    reader.readAsText(blob_2)
  })
}, 'test FileReader InvalidStateError exception for readAsText');

test(function() {
  var blob_1 = new Blob(['TEST000000001'])
  var blob_2 = new Blob(['TEST000000002'])
  var reader = new FileReader();
  reader.readAsDataURL(blob_1)
  assert_equals(reader.readyState, FileReader.LOADING, "readyState Must be LOADING")
  assert_throws_dom("InvalidStateError", function () {
    reader.readAsDataURL(blob_2)
  })
}, 'test FileReader InvalidStateError exception for readAsDataURL');

test(function() {
  var blob_1 = new Blob(['TEST000000001'])
  var blob_2 = new Blob(['TEST000000002'])
  var reader = new FileReader();
  reader.readAsArrayBuffer(blob_1)
  assert_equals(reader.readyState, FileReader.LOADING, "readyState Must be LOADING")
  assert_throws_dom("InvalidStateError", function () {
    reader.readAsArrayBuffer(blob_2)
  })
}, 'test FileReader InvalidStateError exception for readAsArrayBuffer');

async_test(function() {
  var blob_1 = new Blob(['TEST000000001'])
  var blob_2 = new Blob(['TEST000000002'])
  var reader = new FileReader();
  var triggered = false;
  reader.onloadstart = this.step_func_done(function() {
    assert_false(triggered, "Only one loadstart event should be dispatched");
    triggered = true;
    assert_equals(reader.readyState, FileReader.LOADING,
                  "readyState must be LOADING")
    assert_throws_dom("InvalidStateError", function () {
      reader.readAsArrayBuffer(blob_2)
    })
  });
  reader.readAsArrayBuffer(blob_1)
  assert_equals(reader.readyState, FileReader.LOADING, "readyState Must be LOADING")
}, 'test FileReader InvalidStateError exception in onloadstart event for readAsArrayBuffer');

async_test(function() {
  var blob_1 = new Blob(['TEST000000001'])
  var blob_2 = new Blob(['TEST000000002'])
  var reader = new FileReader();
  reader.onloadend = this.step_func_done(function() {
    assert_equals(reader.readyState, FileReader.DONE,
                  "readyState must be DONE")
    reader.readAsArrayBuffer(blob_2)
    assert_equals(reader.readyState, FileReader.LOADING, "readyState Must be LOADING")
  });
  reader.readAsArrayBuffer(blob_1)
  assert_equals(reader.readyState, FileReader.LOADING, "readyState Must be LOADING")
}, 'test FileReader no InvalidStateError exception in loadend event handler for readAsArrayBuffer');

async_test(function() {
  var blob_1 = new Blob([new Uint8Array(0x414141)]);
  var blob_2 = new Blob(['TEST000000002']);
  var reader = new FileReader();
  reader.onloadstart = this.step_func(function() {
    reader.abort();
    reader.onloadstart = null;
    reader.onloadend = this.step_func_done(function() {
      assert_equals('TEST000000002', reader.result);
    });
    reader.readAsText(blob_2);
  });
  reader.readAsText(blob_1);
}, 'test abort and restart in onloadstart event for readAsText');

promise_test(async t => {
  const reader = new FileReader();
  const events = [];

  for (const type of ['abort', 'load', 'loadend']) {
    reader.addEventListener(type, () => events.push(type));
  }

  reader.addEventListener('error', t.unreached_func('Unexpected error event'));
  reader.addEventListener('abort', t.step_func(() => {
    reader.readAsText(new Blob(['second']));
  }),
                          {once: true});

  const firstLoadstart = new Promise(resolve => {
    reader.addEventListener('loadstart', resolve, {once: true});
  });
  const secondLoadend = new Promise(resolve => {
    reader.addEventListener('loadend', t.step_func(() => {
      if (reader.result === 'second') {
        resolve();
      }
    }));
  });

  reader.readAsText(new Blob([new Uint8Array(1024 * 1024)]));
  await firstLoadstart;
  reader.abort();
  await secondLoadend;

  assert_array_equals(events, ['abort', 'load', 'loadend']);
}, 'A new read in an abort handler suppresses the old read loadend');

promise_test(async t => {
  const reader = new FileReader();
  const events = [];
  let load_count = 0;

  for (const type of ['load', 'loadend']) {
    reader.addEventListener(type, () => events.push(type));
  }

  reader.addEventListener('error', t.unreached_func('Unexpected error event'));
  reader.addEventListener('load', t.step_func(() => {
    if (++load_count === 1) {
      reader.readAsText(new Blob(['second']));
    }
  }));

  const secondLoadend = new Promise(resolve => {
    reader.addEventListener('loadend', t.step_func(() => {
      if (reader.result === 'second') {
        resolve();
      }
    }));
  });

  reader.readAsText(new Blob(['first']));
  await secondLoadend;

  assert_array_equals(events, ['load', 'load', 'loadend']);
}, 'A new read in a load handler suppresses the old read loadend');