Start writing simple migrate script

moor/lib/extensions/moor_ffi.dart

@@ -2,4 +2,4 @@
 /// `moor_ffi`.
 library moor_ffi_functions;
 
-export 'package:drift/extensions/ffi.dart';
+export 'package:drift/extensions/native.dart';

moor/lib/ffi.dart

@@ -7,9 +7,9 @@
 /// For more information other platforms, see [other engines](https://moor.simonbinder.eu/docs/other-engines/vm/).
 library moor.ffi;
 
-import 'package:drift/ffi.dart';
+import 'package:drift/native.dart';
 
-export 'package:drift/ffi.dart' hide NativeDatabase;
+export 'package:drift/native.dart' hide NativeDatabase;
 
 /// A moor database implementation based on `dart:ffi`, running directly in a
 /// Dart VM or an AOT compiled Dart/Flutter application.

moor_generator/lib/src/cli/commands/migrate.dart

@@ -4,8 +4,11 @@ import 'dart:io';
 import 'package:analyzer/dart/analysis/analysis_context.dart';
 import 'package:analyzer/dart/analysis/analysis_context_collection.dart';
 import 'package:analyzer/dart/analysis/results.dart';
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/visitor.dart';
+import 'package:moor_generator/src/utils/string_escaper.dart';
 import 'package:path/path.dart' as p;
-import 'package:sqlparser/sqlparser.dart' hide AnalysisContext;
+import 'package:sqlparser/sqlparser.dart' hide AnalysisContext, StringLiteral;
 import 'package:yaml_edit/yaml_edit.dart';
 
 import '../cli.dart';
@@ -64,6 +67,10 @@ class MigrateCommand extends MoorCommand {
     }
 
     final typedResult = unitResult as ResolvedUnitResult;
+    final writer = _Moor2DriftDartRewriter(await file.readAsString());
+    typedResult.unit.accept(writer);
+
+    await file.writeAsString(writer.content);
   }
 
   Future<String> _transformMoorFile(File file) async {
@@ -95,3 +102,55 @@ class MigrateCommand extends MoorCommand {
 
   Future<void> _transformPubspec(File file) async {}
 }
+
+class _Moor2DriftDartRewriter extends GeneralizingAstVisitor<void> {
+  String content;
+  var _skew = 0;
+
+  _Moor2DriftDartRewriter(this.content);
+
+  void _replace(int start, int originalLength, String newContent) {
+    content = content.replaceRange(
+        _skew + start, _skew + start + originalLength, newContent);
+    _skew += newContent.length - originalLength;
+  }
+
+  void _rewriteImportString(StringLiteral l) {
+    // Don't do anything if this is not a 'package:moor/` uri
+    final value = l.stringValue;
+    if (value == null) return;
+
+    final uri = Uri.tryParse(value);
+    if (uri == null || uri.scheme != 'package') return;
+
+    final segments = uri.pathSegments;
+    if (segments.length <= 1 || segments[0] != 'moor') return;
+
+    // Oh, it is a moor package import! Replace with the right drift import.
+    var path = p.url.joinAll(segments.skip(1));
+
+    // Some libraries have a changed path
+    switch (path.toLowerCase()) {
+      case 'moor.dart':
+        path = 'drift.dart'; // moor/moor.dart -> drift/drift.dart
+        break;
+      case 'ffi.dart':
+        path = 'native.dart'; // moor/ffi.dart -> drift/native.dart
+        break;
+      case 'extensions/moor_ffi.dart':
+        path = 'extensions/native.dart'; // similar rename here
+        break;
+      case 'moor_web.dart':
+        path = 'web.dart'; // moor/moor_web.dart -> drift/web.dart
+        break;
+    }
+
+    final driftImport = 'package:drift/$path';
+    _replace(l.offset, l.length, asDartLiteral(driftImport));
+  }
+
+  @override
+  void visitUriBasedDirective(UriBasedDirective node) {
+    _rewriteImportString(node.uri);
+  }
+}

moor_generator/test/cli/migrate_test.dart

@@ -1,9 +1,12 @@
 // @dart=2.9
 import 'dart:async';
 import 'dart:io';
+import 'dart:isolate';
 
 import 'package:meta/meta.dart';
 import 'package:moor_generator/src/cli/cli.dart';
+import 'package:package_config/package_config_types.dart';
+import 'package:path/path.dart' as p;
 import 'package:test/scaffolding.dart';
 import 'package:test_descriptor/test_descriptor.dart' as d;
 
@@ -22,7 +25,23 @@ Future<void> _apply() {
 }
 
 Future<void> _setup(Iterable<d.Descriptor> lib,
-    {String pubspec, Iterable<d.Descriptor> additional}) {
+    {String pubspec, Iterable<d.Descriptor> additional}) async {
+  // Copy and patch moor_generator's package config instead of running `pub get`
+  // in each test.
+
+  final uri = await Isolate.packageConfig;
+  final config =
+      PackageConfig.parseBytes(await File.fromUri(uri).readAsBytes(), uri);
+
+  final appUri = '${File(p.join(d.sandbox, 'app')).absolute.uri}/';
+  final newConfig = PackageConfig([
+    ...config.packages,
+    Package('app', Uri.parse(appUri),
+        packageUriRoot: Uri.parse('${appUri}lib/')),
+  ]);
+  final configBuffer = StringBuffer();
+  PackageConfig.writeString(newConfig, configBuffer);
+
   pubspec ??= '''
 name: app
 
@@ -35,10 +54,13 @@ dev_dependencies:
   moor_generator: ^4.4.0
 ''';
 
-  return d.dir('app', [
+  await d.dir('app', [
     d.dir('lib', lib),
     d.file('pubspec.yaml', pubspec),
-    ...?additional
+    d.dir('.dart_tool', [
+      d.file('package_config.json', configBuffer.toString()),
+    ]),
+    ...?additional,
   ]).create();
 }
 
@@ -54,6 +76,32 @@ void main() {
     await d.dir('app/lib', [
       d.file('a.drift', "import 'b.drift';"),
       d.file('b.drift', 'CREATE TABLE foo (x TEXT);'),
-    ]).create();
+    ]).validate();
+  });
+
+  _test('patches moor imports', () async {
+    await _setup([
+      d.file('a.dart', '''
+import 'package:moor/moor.dart' as moor;
+import 'package:moor/extensions/moor_ffi.dart';
+import 'package:moor/src/some/internal/file.dart';
+
+export 'package:moor/moor_web.dart';
+export 'package:moor/fFI.dart';
+'''),
+    ]);
+
+    await _apply();
+
+    await d.dir('app/lib', [
+      d.file('a.dart', '''
+import 'package:drift/drift.dart' as moor;
+import 'package:drift/extensions/native.dart';
+import 'package:drift/src/some/internal/file.dart';
+
+export 'package:drift/web.dart';
+export 'package:drift/native.dart';
+'''),
+    ]).validate();
   });
 }