Implement author-constructible ReadableStream using V8 extras

third_party/WebKit/LayoutTests/http/tests/streams/readable-streams/tee.js

+'use strict';
+
+if (self.importScripts) {
+  self.importScripts('../resources/rs-utils.js');
+  self.importScripts('/resources/testharness.js');
+}
+
+test(function() {
+    var rs = new ReadableStream();
+
+    var result = rs.tee();
+
+    assert_true(Array.isArray(result), 'return value should be an array');
+    assert_equals(result.length, 2, 'array should have length 2');
+    assert_equals(result[0].constructor, ReadableStream, '0th element should be a ReadableStream');
+    assert_equals(result[1].constructor, ReadableStream, '1st element should be a ReadableStream');
+}, 'ReadableStream teeing: rs.tee() returns an array of two ReadableStreams');
+
+var test1 = async_test('ReadableStream teeing: should be able to read one branch to the end without affecting the other');
+test1.step(function() {
+    var readCalls = 0;
+    var rs = new ReadableStream({
+        start: function(c) {
+            c.enqueue('a');
+            c.enqueue('b');
+            c.close();
+        }
+    });
+
+    var branch = rs.tee();
+    var branch1 = branch[0];
+    var branch2 = branch[1];
+    var reader1 = branch1.getReader();
+    var reader2 = branch2.getReader();
+
+    reader1.closed.then(test1.step_func(function() {
+        assert_equals(readCalls, 4);
+        test1.done();
+    })).catch(test1.step_func(function(e) { assert_unreached(e); }));
+    reader2.closed.then(test1.step_func(function() { assert_unreached('branch2 should not be closed'); }));
+
+    reader1.read().then(test1.step_func(function(r) {
+        assert_object_equals(r, { value: 'a', done: false }, 'first chunk from branch1 should be correct');
+        ++readCalls;
+    }));
+    reader1.read().then(test1.step_func(function(r) {
+        assert_object_equals(r, { value: 'b', done: false }, 'second chunk from branch1 should be correct');
+        ++readCalls;
+    }));
+    reader1.read().then(test1.step_func(function(r) {
+        assert_object_equals(r, { value: undefined, done: true }, 'third read() from branch1 should be done');
+        ++readCalls;
+    }));
+
+    reader2.read().then(test1.step_func(function(r) {
+        assert_object_equals(r, { value: 'a', done: false }, 'first chunk from branch2 should be correct');
+        ++readCalls;
+    }));
+});
+
+var test2 = async_test('ReadableStream teeing: values should be equal across each branch');
+test2.step(function() {
+    var theObject = { the: 'test object' };
+    var rs = new ReadableStream({
+        start: function(c) {
+            c.enqueue(theObject);
+        }
+    });
+
+    var branch = rs.tee();
+    var branch1 = branch[0];
+    var branch2 = branch[1];
+    var reader1 = branch1.getReader();
+    var reader2 = branch2.getReader();
+
+    Promise.all([reader1.read(), reader2.read()]).then(test2.step_func(function(values) {
+        assert_object_equals(values[0], values[1], 'the values should be equal');
+        test2.done();
+    }));
+});
+
+var test3 = async_test('ReadableStream teeing: errors in the source should propagate to both branches');
+test3.step(function() {
+    var closedRejects = 0;
+    var readCalls = 0;
+    var readRejects = 0;
+    var theError = new Error('boo!');
+    var rs = new ReadableStream({
+        start: function(c) {
+            c.enqueue('a');
+            c.enqueue('b');
+        },
+        pull: function() {
+            throw theError;
+        }
+    });
+
+    var branch = rs.tee();
+    var branch1 = branch[0];
+    var branch2 = branch[1];
+    var reader1 = branch1.getReader();
+    var reader2 = branch2.getReader();
+
+    reader1.label = 'reader1';
+    reader2.label = 'reader2';
+
+    reader1.closed.catch(test3.step_func(function(e) {
+        ++closedRejects;
+        assert_equals(e, theError, 'branch1 closed promise should reject with the error');
+    }));
+    reader2.closed.catch(test3.step_func(function(e) {
+        ++closedRejects;
+        assert_equals(e, theError, 'branch2 closed promise should reject with the error');
+    }));
+
+    reader1.read().then(test3.step_func(function(r) {
+        ++readCalls;
+        assert_object_equals(r, { value: 'a', done: false }, 'should be able to read the first chunk in branch1');
+    }));
+
+    reader1.read().then(test3.step_func(function(r) {
+        ++readCalls;
+        assert_object_equals(r, { value: 'b', done: false }, 'should be able to read the second chunk in branch1');
+
+        return reader2.read().then(
+            test3.step_func(function() { assert_unreached('once the root stream has errored, you should not be able to read from branch2'); }),
+            test3.step_func(function(e) {
+                ++readRejects;
+                assert_equals(e, theError, 'branch2 read() promise should reject with the error');
+            }));
+    })).then(test3.step_func(function() {
+        return reader1.read().then(
+            test3.step_func(function() { assert_unreached('once the root stream has errored, you should not be able to read from branch1 either'); }),
+            test3.step_func(function(e) {
+                assert_equals(closedRejects, 2);
+                assert_equals(readCalls, 2);
+                assert_equals(++readRejects, 2);
+                assert_equals(e, theError, 'branch1 read() promise should reject with the error');
+                test3.done();
+            })
+        );
+    })).catch(test3.step_func(function(e) { assert_unreached(e); }));
+});
+
+var test4 = async_test('ReadableStream teeing: canceling branch1 should not impact branch2');
+test4.step(function() {
+    var branch1Read = false;
+    var rs = new ReadableStream({
+        start: function(c) {
+            c.enqueue('a');
+            c.enqueue('b');
+            c.close();
+        }
+    });
+
+    var branch = rs.tee();
+    var branch1 = branch[0];
+    var branch2 = branch[1];
+    branch1.cancel();
+
+    readableStreamToArray(branch1).then(test4.step_func(function(chunks) {
+        assert_array_equals(chunks, [], 'branch1 should have no chunks');
+        branch1Read = true;
+    }));
+
+    readableStreamToArray(branch2).then(test4.step_func(function(chunks) {
+        assert_array_equals(chunks, ['a', 'b'], 'branch2 should have two chunks');
+        assert_true(branch1Read);
+        test4.done();
+    }));
+});
+
+var test5 = async_test('ReadableStream teeing: canceling branch2 should not impact branch1');
+test5.step(function() {
+    var branch2Read = false;
+    var rs = new ReadableStream({
+        start: function(c) {
+            c.enqueue('a');
+            c.enqueue('b');
+            c.close();
+        }
+    });
+
+    var branch = rs.tee();
+    var branch1 = branch[0];
+    var branch2 = branch[1];
+    branch2.cancel();
+
+    readableStreamToArray(branch1).then(test5.step_func(function(chunks) {
+        assert_array_equals(chunks, ['a', 'b'], 'branch1 should have two chunks');
+        assert_true(branch2Read);
+        test5.done();
+    }));
+    readableStreamToArray(branch2).then(test5.step_func(function(chunks) {
+        assert_array_equals(chunks, [], 'branch2 should have no chunks');
+        branch2Read = true;
+    }));
+});
+
+var test6 = async_test('ReadableStream teeing: canceling both branches should aggregate the cancel reasons into an array');
+test6.step(function() {
+    var reason1 = new Error('We\'re wanted men.');
+    var reason2 = new Error('I have the death sentence on twelve systems.');
+
+    var rs = new ReadableStream({
+        cancel: function(reason) {
+            assert_array_equals(reason, [reason1, reason2], 'the cancel reason should be an array containing those from the branches');
+            test6.done();
+        }
+    });
+
+    var branch = rs.tee();
+    var branch1 = branch[0];
+    var branch2 = branch[1];
+    branch1.cancel(reason1);
+    branch2.cancel(reason2);
+});
+
+var test7 = async_test('ReadableStream teeing: failing to cancel the original stream should cause cancel() to reject on branches');
+test7.step(function() {
+    var cancelRejected = false;
+    var theError = new Error('I\'ll be careful.');
+    var rs = new ReadableStream({
+        cancel: function() {
+            throw theError;
+        }
+    });
+
+    var branch = rs.tee();
+    var branch1 = branch[0];
+    var branch2 = branch[1];
+    branch1.cancel().catch(test7.step_func(function(e) {
+        assert_equals(e, theError, 'branch1.cancel() should reject with the error');
+        cancelRejected = true;
+    }));
+    branch2.cancel().catch(test7.step_func(function(e) {
+        assert_equals(e, theError, 'branch2.cancel() should reject with the error');
+        assert_true(cancelRejected);
+        test7.done();
+    }));
+});
+
+var test8 = async_test('ReadableStream teeing: closing the original should immediately close the branches');
+test8.step(function() {
+    var reader1Closed = false;
+    var controller;
+    var rs = new ReadableStream({
+        start: function(c) {
+            controller = c;
+        }
+    });
+
+    var branch = rs.tee();
+    var branch1 = branch[0];
+    var branch2 = branch[1];
+    var reader1 = branch1.getReader();
+    var reader2 = branch2.getReader();
+
+    reader1.closed.then(test8.step_func(function() {
+        reader1Closed = true; //branch1 should be closed
+    })).catch(test8.step_func(function(e) { assert_unreached(e); }));
+    reader2.closed.then(test8.step_func(function() {
+        assert_true(reader1Closed);
+        test8.done('branch2 should be closed');
+    })).catch(test8.step_func(function(e) { assert_unreached(e); }));
+
+    controller.close();
+});
+
+var test9 = async_test('ReadableStream teeing: erroring the original should immediately error the branches');
+test9.step(function() {
+    var reader1Rejected = false;
+    var controller;
+    var rs = new ReadableStream({
+        start(c) {
+            controller = c;
+        }
+    });
+
+    var branch = rs.tee();
+    var branch1 = branch[0];
+    var branch2 = branch[1];
+    var reader1 = branch1.getReader();
+    var reader2 = branch2.getReader();
+
+    var theError = new Error('boo!');
+
+    reader1.closed.then(
+        test9.step_func(function() { assert_unreached('branch1 should not be closed'); }),
+        test9.step_func(function(e) {
+            assert_equals(e, theError, 'branch1 should be errored with the error');
+            reader1Rejected = true;
+        })
+    );
+    reader2.closed.then(
+        test9.step_func(function() { assert_unreached('branch2 should not be closed'); }),
+        test9.step_func(function(e) {
+            assert_equals(e, theError, 'branch2 should be errored with the error');
+            assert_true(reader1Rejected);
+            test9.done();
+        })
+    );
+
+    controller.error(theError);
+});
+
+done();