Expose deallocation functions in NodeJS binding

Author: reuben

native_client/README.md

@@ -100,7 +100,7 @@ After following the above build and installation instructions, the Node.JS bindi
 
 ```
 cd native_client/javascript
-make package
+make build
 make npm-pack
 ```
 

native_client/javascript/client.js

@@ -1,5 +1,4 @@
 #!/usr/bin/env node
-
 'use strict';
 
 const Fs = require('fs');
@@ -69,6 +68,7 @@ function metadataToString(metadata) {
   for (var i = 0; i < metadata.num_items; ++i) {
     retval += metadata.items[i].character;
   }
+  Ds.FreeMetadata(metadata);
   return retval;
 }
 
@@ -135,5 +135,6 @@ audioStream.on('finish', () => {
   }
   const inference_stop = process.hrtime(inference_start);
   console.error('Inference took %ds for %ds audio file.', totalTime(inference_stop), audioLength.toPrecision(4));
+  Ds.DestroyModel(model);
   process.exit(0);
 });

native_client/javascript/deepspeech.i

@@ -28,7 +28,6 @@ using namespace node;
 
 // make sure the string returned by SpeechToText is freed
 %typemap(newfree) char* "DS_FreeString($1);";
-%typemap(newfree) Metadata* "DS_FreeMetadata($1);";
 
 %newobject DS_SpeechToText;
 %newobject DS_IntermediateDecode;
@@ -61,19 +60,8 @@ using namespace node;
   %append_output(SWIG_NewPointerObj(%as_voidptr(*$1), $*1_descriptor, 0));
 }
 
-// extend ModelState with a destructor so that DestroyModel will be called
-// when the JavaScript object gets finalized.
 %nodefaultctor ModelState;
 %nodefaultdtor ModelState;
-
-struct ModelState {};
-
-%extend ModelState {
-  ~ModelState() {
-    DS_DestroyModel($self);
-  }
-}
-
 %nodefaultdtor Metadata;
 %nodefaultctor Metadata;
 %nodefaultctor MetadataItem;
@@ -94,9 +82,6 @@ struct ModelState {};
     v8::Handle<v8::Value> result = SWIGV8_ARRAY_NEW();
     return result;
   }
-  ~Metadata() {
-    DS_FreeMetadata($self);
-  }
 }
 
 %rename ("%(strip:[DS_])s") "";

native_client/javascript/index.js

@@ -75,7 +75,13 @@ Model.prototype.finishStreamWithMetadata = function() {
     return binding.FinishStreamWithMetadata.apply(null, arguments);
 }
 
+function DestroyModel(model) {
+    return binding.DestroyModel(model._impl);
+}
+
 module.exports = {
     Model: Model,
-    printVersions: binding.PrintVersions
+    printVersions: binding.PrintVersions,
+    DestroyModel: DestroyModel,
+    FreeMetadata: binding.FreeMetadata
 };