Remove use of deprecated FFI features via package:ffi.

lib/src/bindings/bindings.dart

@@ -4,8 +4,9 @@
 
 import 'dart:ffi';
 
+import 'package:ffi/ffi.dart';
+
 import 'dlib.dart';
-import 'utf8.dart';
 
 /// Version information for the TensorFlowLite library.
 Pointer<Utf8> Function() TfLiteVersion = tflitelib

lib/src/bindings/interpreter_options.dart

@@ -4,9 +4,10 @@
 
 import 'dart:ffi';
 
+import 'package:ffi/ffi.dart';
+
 import 'dlib.dart';
 import 'types.dart';
-import 'utf8.dart';
 
 /// Returns a new interpreter options instances.
 Pointer<TfLiteInterpreterOptions> Function() TfLiteInterpreterOptionsCreate =

lib/src/bindings/model.dart

@@ -4,9 +4,10 @@
 
 import 'dart:ffi';
 
+import 'package:ffi/ffi.dart';
+
 import 'dlib.dart';
 import 'types.dart';
-import 'utf8.dart';
 
 /// Returns a model from the provided buffer, or null on failure.
 Pointer<TfLiteModel> Function(Pointer<Void> data, int size) TfLiteNewModel =

lib/src/bindings/tensor.dart

@@ -4,9 +4,10 @@
 
 import 'dart:ffi';
 
+import 'package:ffi/ffi.dart';
+
 import 'dlib.dart';
 import 'types.dart';
-import 'utf8.dart';
 
 /// Returns the type of a tensor element.
 TfLiteType TfLiteTensorType(Pointer<TfLiteTensor> t) =>

lib/src/model.dart

@@ -4,11 +4,11 @@
 
 import 'dart:ffi';
 
+import 'package:ffi/ffi.dart';
 import 'package:quiver/check.dart';
 
 import 'bindings/model.dart';
 import 'bindings/types.dart';
-import 'bindings/utf8.dart';
 import 'ffi/helper.dart';
 
 /// TensorFlowLite model.
@@ -24,7 +24,7 @@ class Model {
   factory Model.fromFile(String path) {
     final cpath = Utf8.toUtf8(path);
     final model = TfLiteModelCreateFromFile(cpath);
-    cpath.free();
+    free(cpath);
     checkArgument(isNotNull(model), message: 'Unable to create model.');
     return Model._(model);
   }

lib/src/tensor.dart

@@ -5,11 +5,11 @@
 import 'dart:ffi';
 import 'dart:typed_data';
 
+import 'package:ffi/ffi.dart';
 import 'package:quiver/check.dart';
 
 import 'bindings/tensor.dart';
 import 'bindings/types.dart';
-import 'bindings/utf8.dart';
 import 'ffi/helper.dart';
 
 export 'bindings/types.dart' show TfLiteType;
@@ -57,25 +57,26 @@ class Tensor {
   // TODO(shanehop): Prevent access if unallocated.
   void copyFrom(Uint8List bytes) {
     var size = bytes.length;
-    final ptr = Pointer<Uint8>.allocate(count: size);
+    final ptr = allocate<Uint8>(count: size);
     final externalTypedData = ptr.asExternalTypedData(count: size) as Uint8List;
     externalTypedData.setRange(0, bytes.length, bytes);
     checkState(TfLiteTensorCopyFromBuffer(_tensor, ptr.cast(), bytes.length) ==
         TfLiteStatus.ok);
-    ptr.free();
+    free(ptr);
   }
 
   /// Returns a copy of the underlying data buffer.
   // TODO(shanehop): Prevent access if unallocated.
   Uint8List copyTo() {
     var size = TfLiteTensorByteSize(_tensor);
-    final ptr = Pointer<Uint8>.allocate(count: size);
+    final ptr = allocate<Uint8>(count: size);
     final externalTypedData = ptr.asExternalTypedData(count: size) as Uint8List;
     checkState(
         TfLiteTensorCopyToBuffer(_tensor, ptr.cast(), 4) == TfLiteStatus.ok);
-    // clone the data, because once `ptr.free()`, `externalTypedData` will be volatile
+    // Clone the data, because once `free(ptr)`, `externalTypedData` will be
+    // volatile
     final bytes = externalTypedData.sublist(0);
-    ptr.free();
+    free(ptr);
     return bytes;
   }
 

lib/tflite.dart

@@ -5,8 +5,9 @@
 /// TensorFlow Lite for Dart
 library tflite;
 
+import 'package:ffi/ffi.dart';
+
 import 'src/bindings/bindings.dart';
-import 'src/bindings/utf8.dart';
 
 export 'src/interpreter.dart';
 export 'src/interpreter_options.dart';

pubspec.yaml

@@ -7,11 +7,12 @@ description: >-
 homepage: https://github.com/dart-lang/tflite_native
 
 environment:
-  sdk: '>=2.5.0 <3.0.0'
+  sdk: '>=2.6.0-dev.6.0 <3.0.0'
 
 dependencies:
   path: ^1.6.2
   quiver: ^2.0.3
+  ffi: ^0.1.3-dev.1
 
 dev_dependencies:
   pedantic: ^1.0.0