Merge pull request #238 from genaris/fix/js-string-free

fix(js): free native strings

Author: andrewwhitehead

wrappers/javascript/anoncreds-nodejs/src/NodeJSAnoncreds.ts

@@ -32,12 +32,15 @@ import {
 } from './ffi'
 import { getNativeAnoncreds } from './library'
 
-function handleReturnPointer<Return>(returnValue: Buffer): Return {
+function handleReturnPointer<Return>(returnValue: Buffer, cleanupCallback?: (buffer: Buffer) => void): Return {
   if (returnValue.address() === 0) {
     throw AnoncredsError.customError({ message: 'Unexpected null pointer' })
   }
 
-  return returnValue.deref() as Return
+  const ret = returnValue.deref() as Return
+  if (cleanupCallback) cleanupCallback(returnValue)
+
+  return ret
 }
 
 export class NodeJSAnoncreds implements Anoncreds {
@@ -60,7 +63,7 @@ export class NodeJSAnoncreds implements Anoncreds {
     this.nativeAnoncreds.anoncreds_generate_nonce(ret)
     this.handleError()
 
-    return handleReturnPointer<string>(ret)
+    return handleReturnPointer<string>(ret, this.nativeAnoncreds.anoncreds_string_free)
   }
 
   public createSchema(options: {
@@ -86,7 +89,7 @@ export class NodeJSAnoncreds implements Anoncreds {
     this.nativeAnoncreds.anoncreds_revocation_registry_definition_get_attribute(objectHandle, name, ret)
     this.handleError()
 
-    return handleReturnPointer<string>(ret)
+    return handleReturnPointer<string>(ret, this.nativeAnoncreds.anoncreds_string_free)
   }
 
   public credentialGetAttribute(options: { objectHandle: ObjectHandle; name: string }) {
@@ -96,7 +99,7 @@ export class NodeJSAnoncreds implements Anoncreds {
     this.nativeAnoncreds.anoncreds_credential_get_attribute(objectHandle, name, ret)
     this.handleError()
 
-    return handleReturnPointer<string>(ret)
+    return handleReturnPointer<string>(ret, this.nativeAnoncreds.anoncreds_string_free)
   }
 
   public createCredentialDefinition(options: {
@@ -215,7 +218,7 @@ export class NodeJSAnoncreds implements Anoncreds {
     this.nativeAnoncreds.anoncreds_encode_credential_attributes(attributeRawValues, ret)
     this.handleError()
 
-    const result = handleReturnPointer<string>(ret)
+    const result = handleReturnPointer<string>(ret, this.nativeAnoncreds.anoncreds_string_free)
 
     return result.split(',')
   }
@@ -296,7 +299,7 @@ export class NodeJSAnoncreds implements Anoncreds {
     this.nativeAnoncreds.anoncreds_create_link_secret(ret)
     this.handleError()
 
-    return handleReturnPointer<string>(ret)
+    return handleReturnPointer<string>(ret, this.nativeAnoncreds.anoncreds_string_free)
   }
 
   public createPresentation(options: {
@@ -639,7 +642,7 @@ export class NodeJSAnoncreds implements Anoncreds {
     this.nativeAnoncreds.anoncreds_get_current_error(ret)
     this.handleError()
 
-    return handleReturnPointer<string>(ret)
+    return handleReturnPointer<string>(ret, this.nativeAnoncreds.anoncreds_string_free)
   }
 
   private objectFromJson(method: (byteBuffer: Buffer, ret: Buffer) => unknown, options: { json: string }) {
@@ -721,9 +724,13 @@ export class NodeJSAnoncreds implements Anoncreds {
     this.handleError()
 
     const returnValue = handleReturnPointer<{ data: Buffer; len: number }>(ret)
-    const output = new Uint8Array(byteBufferToBuffer(returnValue))
+    const jsonAsArray = new Uint8Array(byteBufferToBuffer(returnValue))
+
+    const output = new TextDecoder().decode(jsonAsArray)
+
+    this.nativeAnoncreds.anoncreds_buffer_free(returnValue.data)
 
-    return new TextDecoder().decode(output)
+    return output
   }
 
   public getTypeName(options: { objectHandle: ObjectHandle }) {
@@ -734,7 +741,7 @@ export class NodeJSAnoncreds implements Anoncreds {
     this.nativeAnoncreds.anoncreds_object_get_type_name(objectHandle, ret)
     this.handleError()
 
-    return handleReturnPointer<string>(ret)
+    return handleReturnPointer<string>(ret, this.nativeAnoncreds.anoncreds_string_free)
   }
 
   public objectFree(options: { objectHandle: ObjectHandle }) {

wrappers/javascript/anoncreds-nodejs/src/library/bindings.ts

@@ -120,6 +120,7 @@ export const nativeBindings = {
   anoncreds_generate_nonce: [FFI_ERRORCODE, [FFI_STRING_PTR]],
   anoncreds_get_current_error: [FFI_ERRORCODE, [FFI_STRING_PTR]],
   anoncreds_object_free: [FFI_VOID, [FFI_OBJECT_HANDLE]],
+  anoncreds_string_free: [FFI_VOID, [FFI_STRING_PTR]],
   anoncreds_object_get_json: [FFI_ERRORCODE, [FFI_OBJECT_HANDLE, ByteBufferStructPtr]],
   anoncreds_object_get_type_name: [FFI_ERRORCODE, [FFI_OBJECT_HANDLE, FFI_STRING_PTR]],
   anoncreds_presentation_request_from_json: [FFI_ERRORCODE, [ByteBufferStruct, FFI_STRING_PTR]],

wrappers/javascript/anoncreds-react-native/cpp/turboModuleUtility.cpp

@@ -49,6 +49,8 @@ jsi::Value createReturnValue(jsi::Runtime &rt, ErrorCode code,
                                    ? jsi::Value::null()
                                    : jsi::String::createFromAscii(rt, *value);
     object.setProperty(rt, "value", valueWithoutNullptr);
+
+    if (!isNullptr) anoncreds_string_free((char *)*value);
   }
 
   object.setProperty(rt, "errorCode", int(code));
@@ -98,6 +100,8 @@ jsi::Value createReturnValue(jsi::Runtime &rt, ErrorCode code,
             ? jsi::Value::null()
             : jsi::String::createFromUtf8(rt, value->data, value->len);
     object.setProperty(rt, "value", valueWithoutNullptr);
+
+    if (value != nullptr) anoncreds_buffer_free(*value);
   }
 
   object.setProperty(rt, "errorCode", int(code));