Method writableStream

Tests/Libraries/AsyncStreams/AsyncStreamsTest.cpp:327–406

}

void SC::AsyncStreamsTest::writableStream()
{
    constexpr size_t numberOfBuffers = 2;
    AsyncBufferView  bufferViews[numberOfBuffers]; // Empty BufferViews (to be filled with ReadOnly ones)
    AsyncBuffersPool pool;
    pool.setBuffers(bufferViews);

    struct TestWritableStream : public AsyncWritableStream
    {
        size_t numAsyncWrites = 0;
        String concatenated;

        AsyncBufferView::ID bufferID;

        virtual Result asyncWrite(AsyncBufferView::ID incomingBufferID, Function<void(AsyncBufferView::ID)> cb) override
        {
            (void)cb;
            numAsyncWrites++;
            Span<const char> data;
            SC_TRY(getBuffersPool().getReadableData(incomingBufferID, data));
            StringView sv(data, false, StringEncoding::Ascii);
            SC_TRY(StringBuilder::createForAppendingTo(concatenated).append(sv));
            bufferID = incomingBufferID;
            return Result(true);
        }
    };
    TestWritableStream           writable;
    AsyncWritableStream::Request writeRequestsQueue[numberOfBuffers + 1]; // Only N-1 slots will be used
    writable.setWriteQueue(writeRequestsQueue);
    SC_TEST_EXPECT(writable.init(pool));
    (void)writable.eventError.addListener([this](Result res) { SC_TEST_EXPECT(res); });

    int numDrain = 0;
    (void)writable.eventDrain.addListener([&numDrain] { numDrain++; });

    // When passing String(...) the writable takes ownership of the String destroying it after the write
    SC_TEST_EXPECT(writable.write(String("1"))); // Executes asyncWrites and queue slot is freed immediately
    SC_TEST_EXPECT(writable.numAsyncWrites == 1);
    SC_TEST_EXPECT(writable.write("2"));         // queued, uses first write slot
    SC_TEST_EXPECT(writable.write(String("3"))); // queued, uses second write slot
    SC_TEST_EXPECT(not writable.write("4"));     // no more write queue slots
    SC_TEST_EXPECT(writable.numAsyncWrites == 1);
    writable.finishedWriting(writable.bufferID, {}, Result(true)); // writes 2
    SC_TEST_EXPECT(writable.concatenated == "12");
    SC_TEST_EXPECT(numDrain == 0);
    SC_TEST_EXPECT(writable.numAsyncWrites == 2);
    SC_TEST_EXPECT(writable.write("4"));
    SC_TEST_EXPECT(writable.numAsyncWrites == 2);
    SC_TEST_EXPECT(not writable.write(String("5")));
    writable.finishedWriting(writable.bufferID, {}, Result(true)); // writes 3
    SC_TEST_EXPECT(writable.concatenated == "123");
    SC_TEST_EXPECT(numDrain == 0);
    writable.finishedWriting(writable.bufferID, {}, Result(true)); // writes 4
    SC_TEST_EXPECT(writable.concatenated == "1234");
    SC_TEST_EXPECT(numDrain == 0);
    writable.finishedWriting(writable.bufferID, {}, Result(true)); // writes nothing
    SC_TEST_EXPECT(writable.concatenated == "1234");
    SC_TEST_EXPECT(numDrain == 1);