Clean up handling of optional args in C++ with c10:optional (#1043)

torchaudio/csrc/sox_effects.cpp

@@ -91,8 +91,8 @@ c10::intrusive_ptr<TensorSignal> apply_effects_tensor(
 c10::intrusive_ptr<TensorSignal> apply_effects_file(
     const std::string path,
     std::vector<std::vector<std::string>> effects,
-    const bool normalize,
-    const bool channels_first) {
+    c10::optional<bool>& normalize,
+    c10::optional<bool>& channels_first) {
   // Open input file
   SoxFormat sf(sox_open_read(
       path.c_str(),
@@ -121,16 +121,17 @@ c10::intrusive_ptr<TensorSignal> apply_effects_file(
   chain.run();
 
   // Create tensor from buffer
+  bool channels_first_ = channels_first.value_or(true);
   auto tensor = convert_to_tensor(
       /*buffer=*/out_buffer.data(),
       /*num_samples=*/out_buffer.size(),
       /*num_channels=*/chain.getOutputNumChannels(),
       dtype,
-      normalize,
-      channels_first);
+      normalize.value_or(true),
+      channels_first_);
 
   return c10::make_intrusive<TensorSignal>(
-      tensor, chain.getOutputSampleRate(), channels_first);
+      tensor, chain.getOutputSampleRate(), channels_first_);
 }
 
 } // namespace sox_effects

torchaudio/csrc/sox_effects.h

@@ -18,8 +18,8 @@ c10::intrusive_ptr<torchaudio::sox_utils::TensorSignal> apply_effects_tensor(
 c10::intrusive_ptr<torchaudio::sox_utils::TensorSignal> apply_effects_file(
     const std::string path,
     std::vector<std::vector<std::string>> effects,
-    const bool normalize = true,
-    const bool channels_first = true);
+    c10::optional<bool>& normalize,
+    c10::optional<bool>& channels_first);
 
 } // namespace sox_effects
 } // namespace torchaudio

torchaudio/csrc/sox_io.cpp

@@ -49,30 +49,32 @@ c10::intrusive_ptr<SignalInfo> get_info(const std::string& path) {
 
 c10::intrusive_ptr<TensorSignal> load_audio_file(
     const std::string& path,
-    const int64_t frame_offset,
-    const int64_t num_frames,
-    const bool normalize,
-    const bool channels_first) {
-  if (frame_offset < 0) {
+    c10::optional<int64_t>& frame_offset,
+    c10::optional<int64_t>& num_frames,
+    c10::optional<bool>& normalize,
+    c10::optional<bool>& channels_first) {
+  const auto offset = frame_offset.value_or(0);
+  if (offset < 0) {
     throw std::runtime_error(
         "Invalid argument: frame_offset must be non-negative.");
   }
-  if (num_frames == 0 || num_frames < -1) {
+  const auto frames = num_frames.value_or(-1);
+  if (frames == 0 || frames < -1) {
     throw std::runtime_error(
         "Invalid argument: num_frames must be -1 or greater than 0.");
   }
 
   std::vector<std::vector<std::string>> effects;
-  if (num_frames != -1) {
-    std::ostringstream offset, frames;
-    offset << frame_offset << "s";
-    frames << "+" << num_frames << "s";
+  if (frames != -1) {
+    std::ostringstream os_offset, os_frames;
+    os_offset << offset << "s";
+    os_frames << "+" << frames << "s";
     effects.emplace_back(
-        std::vector<std::string>{"trim", offset.str(), frames.str()});
-  } else if (frame_offset != 0) {
-    std::ostringstream offset;
-    offset << frame_offset << "s";
-    effects.emplace_back(std::vector<std::string>{"trim", offset.str()});
+        std::vector<std::string>{"trim", os_offset.str(), os_frames.str()});
+  } else if (offset != 0) {
+    std::ostringstream os_offset;
+    os_offset << offset << "s";
+    effects.emplace_back(std::vector<std::string>{"trim", os_offset.str()});
   }
 
   return torchaudio::sox_effects::apply_effects_file(

torchaudio/csrc/sox_io.h

@@ -25,10 +25,10 @@ c10::intrusive_ptr<SignalInfo> get_info(const std::string& path);
 
 c10::intrusive_ptr<torchaudio::sox_utils::TensorSignal> load_audio_file(
     const std::string& path,
-    const int64_t frame_offset = 0,
-    const int64_t num_frames = -1,
-    const bool normalize = true,
-    const bool channels_first = true);
+    c10::optional<int64_t>& frame_offset,
+    c10::optional<int64_t>& num_frames,
+    c10::optional<bool>& normalize,
+    c10::optional<bool>& channels_first);
 
 void save_audio_file(
     const std::string& file_name,