pass token_ids from inference

crates/ctranslate2-bindings/include/ctranslate2.h

@@ -12,7 +12,7 @@ typedef rust::Fn<bool(InferenceContext&, size_t, uint32_t, rust::String)> Infere
 class TextInferenceEngine {
  public:
   virtual ~TextInferenceEngine();
-  virtual rust::Vec<rust::String> inference(
+  virtual rust::Vec<uint32_t> inference(
       rust::Box<InferenceContext> context,
       InferenceCallback callback,
       rust::Slice<const rust::String> tokens,

crates/ctranslate2-bindings/src/ctranslate2.cc

@@ -15,7 +15,7 @@ class TextInferenceEngineImpl : public TextInferenceEngine {
   };
 
  public:
-  rust::Vec<rust::String> inference(
+  rust::Vec<uint32_t> inference(
       rust::Box<InferenceContext> context,
       InferenceCallback callback,
       rust::Slice<const rust::String> tokens,
@@ -24,18 +24,12 @@ class TextInferenceEngineImpl : public TextInferenceEngine {
   ) const {
     // Inference.
     std::vector<std::string> input_tokens(tokens.begin(), tokens.end());
-    const auto output_tokens = process(
+    return process(
         std::move(context),
         std::move(callback),
         input_tokens,
         Options{max_decoding_length, sampling_temperature}
     );
-
-    // Convert to rust vec.
-    rust::Vec<rust::String> output;
-    output.reserve(output_tokens.size());
-    std::copy(output_tokens.begin(), output_tokens.end(), std::back_inserter(output));
-    return output;
   }
 
   static std::unique_ptr<TextInferenceEngine> create(const ctranslate2::models::ModelLoader& loader) {
@@ -45,7 +39,7 @@ class TextInferenceEngineImpl : public TextInferenceEngine {
   }
 
  protected:
-  virtual std::vector<std::string> process(
+  virtual rust::Vec<uint32_t> process(
       rust::Box<InferenceContext> context,
       InferenceCallback callback,
       const std::vector<std::string>& tokens,
@@ -55,7 +49,7 @@ class TextInferenceEngineImpl : public TextInferenceEngine {
 
 class EncoderDecoderImpl : public TextInferenceEngineImpl<ctranslate2::Translator, EncoderDecoderImpl> {
  protected:
-  virtual std::vector<std::string> process(
+  virtual rust::Vec<uint32_t> process(
       rust::Box<InferenceContext> context,
       InferenceCallback callback,
       const std::vector<std::string>& tokens,
@@ -64,17 +58,24 @@ class EncoderDecoderImpl : public TextInferenceEngineImpl<ctranslate2::Translato
     x.max_decoding_length = options.max_decoding_length;
     x.sampling_temperature = options.sampling_temperature;
     x.beam_size = 1;
+    rust::Vec<uint32_t> output_ids;
     x.callback = [&](ctranslate2::GenerationStepResult result) {
-      return callback(*context, result.step, result.token_id, result.token);
+      bool stop = callback(*context, result.step, result.token_id, result.token);
+      if (!stop) {
+        output_ids.push_back(result.token_id);
+      } else if (result.is_last) {
+        output_ids.push_back(result.token_id);
+      }
+      return stop;
     };
     ctranslate2::TranslationResult result = model_->translate_batch({ tokens }, x)[0];
-    return std::move(result.output());
+    return output_ids;
   }
 };
 
 class DecoderImpl : public TextInferenceEngineImpl<ctranslate2::Generator, DecoderImpl> {
  protected:
-  virtual std::vector<std::string> process(
+  virtual rust::Vec<uint32_t> process(
       rust::Box<InferenceContext> context,
       InferenceCallback callback,
       const std::vector<std::string>& tokens,
@@ -84,11 +85,19 @@ class DecoderImpl : public TextInferenceEngineImpl<ctranslate2::Generator, Decod
     x.max_length = options.max_decoding_length;
     x.sampling_temperature = options.sampling_temperature;
     x.beam_size = 1;
+
+    rust::Vec<uint32_t> output_ids;
     x.callback = [&](ctranslate2::GenerationStepResult result) {
-      return callback(*context, result.step, result.token_id, result.token);
+      bool stop = callback(*context, result.step, result.token_id, result.token);
+      if (!stop) {
+        output_ids.push_back(result.token_id);
+      } else if (result.is_last) {
+        output_ids.push_back(result.token_id);
+      }
+      return stop;
     };
     ctranslate2::GenerationResult result = model_->generate_batch_async({ tokens }, x)[0].get();
-    return std::move(result.sequences[0]);
+    return output_ids;
   }
 };
 

crates/ctranslate2-bindings/src/lib.rs

@@ -39,7 +39,7 @@ mod ffi {
             tokens: &[String],
             max_decoding_length: usize,
             sampling_temperature: f32,
-        ) -> Vec<String>;
+        ) -> Vec<u32>;
     }
 }
 
@@ -122,7 +122,7 @@ impl TextInferenceEngine {
         };
 
         let context = InferenceContext::new(stop_re, cancel_for_inference);
-        let output_tokens = tokio::task::spawn_blocking(move || {
+        let output_ids = tokio::task::spawn_blocking(move || {
             let context = Box::new(context);
             engine.inference(
                 context,
@@ -134,23 +134,7 @@ impl TextInferenceEngine {
         })
         .await
         .expect("Inference failed");
-        let output_ids: Vec<u32> = output_tokens
-            .iter()
-            .filter_map(|x| match self.tokenizer.token_to_id(x) {
-                Some(y) => Some(y),
-                None => {
-                    println!("Warning: token ({}) missed in vocab", x);
-                    None
-                }
-            })
-            .collect();
-        let output_text = self.tokenizer.decode(output_ids, true).unwrap();
-        for stop_word in options.stop_words {
-            if let Some(stripped_text) = output_text.strip_suffix(stop_word) {
-                return stripped_text.to_string();
-            }
-        }
-        output_text
+        self.tokenizer.decode(output_ids, true).unwrap()
     }
 }