Makes decode and decode_batch work on borrowed content. (#1251)

* Makes `decode` and `decode_batch` work on borrowed content.

* Make `decode_batch` work with borrowed content.

* Fix lint.

* Attempt to map it into Node.

* Second attempt.

* Step by step.

* One more step.

* Fix lint.

* Please ...

* Removing collect.

* Revert "Removing collect."

This reverts commit 2f7ec04.

---------

Co-authored-by: Nicolas Patry <patry.nicolas@protonmail.com>

bindings/node/native/src/tasks/tokenizer.rs

@@ -106,14 +106,17 @@ impl Task for DecodeTask {
                 .tokenizer
                 .read()
                 .unwrap()
-                .decode(ids.to_vec(), *skip_special_tokens)
+                .decode(ids.as_slice(), *skip_special_tokens)
                 .map_err(|e| format!("{}", e))
                 .map(DecodeOutput::Single),
             DecodeTask::Batch(worker, ids, skip_special_tokens) => worker
                 .tokenizer
                 .read()
                 .unwrap()
-                .decode_batch(ids.to_vec(), *skip_special_tokens)
+                .decode_batch(
+                    &ids.iter().map(|v| v.as_slice()).collect::<Vec<&[u32]>>(),
+                    *skip_special_tokens,
+                )
                 .map_err(|e| format!("{}", e))
                 .map(DecodeOutput::Batch),
         }

bindings/python/src/tokenizer.rs

@@ -1009,7 +1009,7 @@ impl PyTokenizer {
     #[pyo3(signature = (ids, skip_special_tokens = true))]
     #[pyo3(text_signature = "(self, ids, skip_special_tokens=True)")]
     fn decode(&self, ids: Vec<u32>, skip_special_tokens: bool) -> PyResult<String> {
-        ToPyResult(self.tokenizer.decode(ids, skip_special_tokens)).into()
+        ToPyResult(self.tokenizer.decode(&ids, skip_special_tokens)).into()
     }
 
     /// Decode a batch of ids back to their corresponding string
@@ -1032,7 +1032,8 @@ impl PyTokenizer {
         skip_special_tokens: bool,
     ) -> PyResult<Vec<String>> {
         py.allow_threads(|| {
-            ToPyResult(self.tokenizer.decode_batch(sequences, skip_special_tokens)).into()
+            let slices = sequences.iter().map(|v| &v[..]).collect::<Vec<&[u32]>>();
+            ToPyResult(self.tokenizer.decode_batch(&slices, skip_special_tokens)).into()
         })
     }
 

tokenizers/src/cli.rs

@@ -59,7 +59,7 @@ fn shell(vocab: &str, merges: &str) -> Result<()> {
         println!("Offsets:\t{:?}", encoded.get_offsets());
         println!(
             "Decoded:\t{}",
-            tokenizer.decode(encoded.get_ids().to_vec(), true).unwrap()
+            tokenizer.decode(encoded.get_ids(), true).unwrap()
         );
         println!("Tokenized in {:?}", elapsed);
     }

tokenizers/src/tokenizer/mod.rs

@@ -795,12 +795,12 @@ where
     }
 
     /// Decode the given ids, back to a String
-    pub fn decode(&self, ids: Vec<u32>, skip_special_tokens: bool) -> Result<String> {
+    pub fn decode(&self, ids: &[u32], skip_special_tokens: bool) -> Result<String> {
         let tokens = ids
-            .into_iter()
+            .iter()
             .filter_map(|id| {
                 self.added_vocabulary
-                    .id_to_token(id, &self.model)
+                    .id_to_token(*id, &self.model)
                     .filter(|token| {
                         !skip_special_tokens || !self.added_vocabulary.is_special_token(token)
                     })
@@ -1008,7 +1008,7 @@ where
     /// Decode all sentences in parallel
     pub fn decode_batch(
         &self,
-        sentences: Vec<Vec<u32>>,
+        sentences: &[&[u32]],
         skip_special_tokens: bool,
     ) -> Result<Vec<String>>
     where

tokenizers/tests/documentation.rs

@@ -54,7 +54,7 @@ fn load_tokenizer() {
     assert_eq!(encodings.get_ids(), ids);
     assert_eq!(encodings.get_tokens(), tokens);
 
-    let decoded = tokenizer.decode(ids, false).unwrap();
+    let decoded = tokenizer.decode(&ids, false).unwrap();
     assert_eq!(decoded, example);
 }
 
@@ -347,7 +347,7 @@ fn pipeline() -> tokenizers::Result<()> {
     // [1, 27253, 16, 93, 11, 5097, 5, 7961, 5112, 6218, 0, 35, 2]
 
     let decoded = tokenizer.decode(
-        vec![1, 27253, 16, 93, 11, 5097, 5, 7961, 5112, 6218, 0, 35, 2],
+        &[1, 27253, 16, 93, 11, 5097, 5, 7961, 5112, 6218, 0, 35, 2],
         true,
     )?;
     println!("{}", decoded);
@@ -435,7 +435,7 @@ fn pipeline_bert() -> tokenizers::Result<()> {
     println!("{:?}", output.get_tokens());
     // ["[CLS]", "welcome", "to", "the", "[UNK]", "tok", "##eni", "##zer", "##s", "library", ".", "[SEP]"]
 
-    let decoded = bert_tokenizer.decode(output.get_ids().to_vec(), true)?;
+    let decoded = bert_tokenizer.decode(output.get_ids(), true)?;
     println!("{}", decoded);
     // "welcome to the tok ##eni ##zer ##s library ."
     // END bert_test_decoding
@@ -451,7 +451,7 @@ fn pipeline_bert() -> tokenizers::Result<()> {
     use tokenizers::decoders::wordpiece::WordPiece as WordPieceDecoder;
 
     bert_tokenizer.with_decoder(WordPieceDecoder::default());
-    let decoded = bert_tokenizer.decode(output.get_ids().to_vec(), true)?;
+    let decoded = bert_tokenizer.decode(output.get_ids(), true)?;
     // "welcome to the tokenizers library."
     // END bert_proper_decoding
     assert_eq!(decoded, "welcome to the tokenizers library.");