Check write buffer on stream closed check (#1578)

Helps to avoid "empty JSON" errors when stream is being reset

Relates-To: DATASDK-57

Signed-off-by: Andrey Kashcheev <ext-andrey.kashcheev@here.com>

olp-cpp-sdk-dataservice-read/src/repositories/AsyncJsonStream.cpp

@@ -50,7 +50,10 @@ size_t RapidJsonByteStream::PutEnd(char*) { return 0; }
 bool RapidJsonByteStream::ReadEmpty() const {
   return count_ == read_buffer_.size();
 }
-bool RapidJsonByteStream::WriteEmpty() const { return write_buffer_.empty(); }
+bool RapidJsonByteStream::WriteEmpty() const {
+  std::unique_lock<std::mutex> lock(mutex_);
+  return write_buffer_.empty();
+}
 
 void RapidJsonByteStream::AppendContent(const char* content, size_t length) {
   std::unique_lock<std::mutex> lock(mutex_);
@@ -64,7 +67,7 @@ void RapidJsonByteStream::AppendContent(const char* content, size_t length) {
 
 void RapidJsonByteStream::SwapBuffers() {
   std::unique_lock<std::mutex> lock(mutex_);
-  cv_.wait(lock, [&]() { return !WriteEmpty(); });
+  cv_.wait(lock, [&]() { return !write_buffer_.empty(); });
   std::swap(read_buffer_, write_buffer_);
   write_buffer_.clear();
   count_ = 0;
@@ -114,7 +117,7 @@ boost::optional<client::ApiError> AsyncJsonStream::GetError() const {
 
 bool AsyncJsonStream::IsClosed() const {
   std::unique_lock<std::mutex> lock(mutex_);
-  return closed_;
+  return closed_ && (error_ || current_stream_->WriteEmpty());
 }
 
 }  // namespace repository

olp-cpp-sdk-dataservice-read/tests/PartitionsRepositoryTest.cpp

@@ -2076,10 +2076,13 @@ TEST_F(PartitionsRepositoryTest, StreamPartitions) {
 
     repository.StreamPartitions(async_stream, kVersion, additional_fields,
                                 billing_tag, context);
-    EXPECT_TRUE(async_stream->IsClosed());
+    // Not closed since the stream is not empty
+    EXPECT_FALSE(async_stream->IsClosed());
     EXPECT_FALSE(async_stream->GetError());
     EXPECT_STREQ(ref_stream_data.c_str(),
                  get_stream_content(*async_stream).c_str());
+    // Now it's closed as we read all its content
+    EXPECT_TRUE(async_stream->IsClosed());
 
     {
       SCOPED_TRACE("Data with offset is in the stream");
@@ -2091,10 +2094,13 @@ TEST_F(PartitionsRepositoryTest, StreamPartitions) {
       repository.StreamPartitions(second_stream, kVersion, additional_fields,
                                   billing_tag, context);
 
-      EXPECT_TRUE(second_stream->IsClosed());
+      // Not closed since the stream is not empty
+      EXPECT_FALSE(second_stream->IsClosed());
       EXPECT_FALSE(second_stream->GetError());
       EXPECT_STREQ((initial_value + ref_stream_data).c_str(),
                    get_stream_content(*second_stream).c_str());
+      // Now it's closed as we read all its content
+      EXPECT_TRUE(second_stream->IsClosed());
     }
   }
 }