1 files changed, 264 insertions, 0 deletions
diff --git a/testing/web-platform/tests/streams/readable-streams/reentrant-strategies.any.js b/testing/web-platform/tests/streams/readable-streams/reentrant-strategies.any.js
new file mode 100644
index 0000000000..b4988bc243
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+++ b/testing/web-platform/tests/streams/readable-streams/reentrant-strategies.any.js
@@ -0,0 +1,264 @@
+// META: global=window,worker
+// META: script=../resources/recording-streams.js
+// META: script=../resources/rs-utils.js
+// META: script=../resources/test-utils.js
+'use strict';
+
+// The size() function of the readable strategy can re-entrantly call back into the ReadableStream implementation. This
+// makes it risky to cache state across the call to ReadableStreamDefaultControllerEnqueue. These tests attempt to catch
+// such errors. They are separated from the other strategy tests because no real user code should ever do anything like
+// this.
+
+const error1 = new Error('error1');
+error1.name = 'error1';
+
+promise_test(() => {
+  let controller;
+  let calls = 0;
+  const rs = new ReadableStream({
+    start(c) {
+      controller = c;
+    }
+  }, {
+    size() {
+      ++calls;
+      if (calls < 2) {
+        controller.enqueue('b');
+      }
+      return 1;
+    }
+  });
+  controller.enqueue('a');
+  controller.close();
+  return readableStreamToArray(rs)
+      .then(array => assert_array_equals(array, ['b', 'a'], 'array should contain two chunks'));
+}, 'enqueue() inside size() should work');
+
+promise_test(() => {
+  let controller;
+  const rs = new ReadableStream({
+    start(c) {
+      controller = c;
+    }
+  }, {
+    size() {
+      // The queue is empty.
+      controller.close();
+      // The state has gone from "readable" to "closed".
+      return 1;
+      // This chunk will be enqueued, but will be impossible to read because the state is already "closed".
+    }
+  });
+  controller.enqueue('a');
+  return readableStreamToArray(rs)
+      .then(array => assert_array_equals(array, [], 'array should contain no chunks'));
+  // The chunk 'a' is still in rs's queue. It is closed so 'a' cannot be read.
+}, 'close() inside size() should not crash');
+
+promise_test(() => {
+  let controller;
+  let calls = 0;
+  const rs = new ReadableStream({
+    start(c) {
+      controller = c;
+    }
+  }, {
+    size() {
+      ++calls;
+      if (calls === 2) {
+        // The queue contains one chunk.
+        controller.close();
+        // The state is still "readable", but closeRequest is now true.
+      }
+      return 1;
+    }
+  });
+  controller.enqueue('a');
+  controller.enqueue('b');
+  return readableStreamToArray(rs)
+      .then(array => assert_array_equals(array, ['a', 'b'], 'array should contain two chunks'));
+}, 'close request inside size() should work');
+
+promise_test(t => {
+  let controller;
+  const rs = new ReadableStream({
+    start(c) {
+      controller = c;
+    }
+  }, {
+    size() {
+      controller.error(error1);
+      return 1;
+    }
+  });
+  controller.enqueue('a');
+  return promise_rejects_exactly(t, error1, rs.getReader().read(), 'read() should reject');
+}, 'error() inside size() should work');
+
+promise_test(() => {
+  let controller;
+  const rs = new ReadableStream({
+    start(c) {
+      controller = c;
+    }
+  }, {
+    size() {
+      assert_equals(controller.desiredSize, 1, 'desiredSize should be 1');
+      return 1;
+    },
+    highWaterMark: 1
+  });
+  controller.enqueue('a');
+  controller.close();
+  return readableStreamToArray(rs)
+      .then(array => assert_array_equals(array, ['a'], 'array should contain one chunk'));
+}, 'desiredSize inside size() should work');
+
+promise_test(t => {
+  let cancelPromise;
+  let controller;
+  const rs = new ReadableStream({
+    start(c) {
+      controller = c;
+    },
+    cancel: t.step_func(reason => {
+      assert_equals(reason, error1, 'reason should be error1');
+      assert_throws_js(TypeError, () => controller.enqueue(), 'enqueue() should throw');
+    })
+  }, {
+    size() {
+      cancelPromise = rs.cancel(error1);
+      return 1;
+    },
+    highWaterMark: Infinity
+  });
+  controller.enqueue('a');
+  const reader = rs.getReader();
+  return Promise.all([
+    reader.closed,
+    cancelPromise
+  ]);
+}, 'cancel() inside size() should work');
+
+promise_test(() => {
+  let controller;
+  let pipeToPromise;
+  const ws = recordingWritableStream();
+  const rs = new ReadableStream({
+    start(c) {
+      controller = c;
+    }
+  }, {
+    size() {
+      if (!pipeToPromise) {
+        pipeToPromise = rs.pipeTo(ws);
+      }
+      return 1;
+    },
+    highWaterMark: 1
+  });
+  controller.enqueue('a');
+  assert_not_equals(pipeToPromise, undefined);
+
+  // Some pipeTo() implementations need an additional chunk enqueued in order for the first one to be processed. See
+  // https://github.com/whatwg/streams/issues/794 for background.
+  controller.enqueue('a');
+
+  // Give pipeTo() a chance to process the queued chunks.
+  return delay(0).then(() => {
+    assert_array_equals(ws.events, ['write', 'a', 'write', 'a'], 'ws should contain two chunks');
+    controller.close();
+    return pipeToPromise;
+  }).then(() => {
+    assert_array_equals(ws.events, ['write', 'a', 'write', 'a', 'close'], 'target should have been closed');
+  });
+}, 'pipeTo() inside size() should behave as expected');
+
+promise_test(() => {
+  let controller;
+  let readPromise;
+  let calls = 0;
+  let readResolved = false;
+  let reader;
+  const rs = new ReadableStream({
+    start(c) {
+      controller = c;
+    }
+  }, {
+    size() {
+      // This is triggered by controller.enqueue(). The queue is empty and there are no pending reads. This read is
+      // added to the list of pending reads.
+      readPromise = reader.read();
+      ++calls;
+      return 1;
+    },
+    highWaterMark: 0
+  });
+  reader = rs.getReader();
+  controller.enqueue('a');
+  readPromise.then(() => {
+    readResolved = true;
+  });
+  return flushAsyncEvents().then(() => {
+    assert_false(readResolved);
+    controller.enqueue('b');
+    assert_equals(calls, 1, 'size() should have been called once');
+    return delay(0);
+  }).then(() => {
+    assert_true(readResolved);
+    assert_equals(calls, 1, 'size() should only be called once');
+    return readPromise;
+  }).then(({ value, done }) => {
+    assert_false(done, 'done should be false');
+    // See https://github.com/whatwg/streams/issues/794 for why this chunk is not 'a'.
+    assert_equals(value, 'b', 'chunk should have been read');
+    assert_equals(calls, 1, 'calls should still be 1');
+    return reader.read();
+  }).then(({ value, done }) => {
+    assert_false(done, 'done should be false again');
+    assert_equals(value, 'a', 'chunk a should come after b');
+  });
+}, 'read() inside of size() should behave as expected');
+
+promise_test(() => {
+  let controller;
+  let reader;
+  const rs = new ReadableStream({
+    start(c) {
+      controller = c;
+    }
+  }, {
+    size() {
+      reader = rs.getReader();
+      return 1;
+    }
+  });
+  controller.enqueue('a');
+  return reader.read().then(({ value, done }) => {
+    assert_false(done, 'done should be false');
+    assert_equals(value, 'a', 'value should be a');
+  });
+}, 'getReader() inside size() should work');
+
+promise_test(() => {
+  let controller;
+  let branch1;
+  let branch2;
+  const rs = new ReadableStream({
+    start(c) {
+      controller = c;
+    }
+  }, {
+    size() {
+      [branch1, branch2] = rs.tee();
+      return 1;
+    }
+  });
+  controller.enqueue('a');
+  assert_true(rs.locked, 'rs should be locked');
+  controller.close();
+  return Promise.all([
+    readableStreamToArray(branch1).then(array => assert_array_equals(array, ['a'], 'branch1 should have one chunk')),
+    readableStreamToArray(branch2).then(array => assert_array_equals(array, ['a'], 'branch2 should have one chunk'))
+  ]);
+}, 'tee() inside size() should work');