Add IncrementalKernelGenerator.acceptLastDelta()/rejectLastDelta().

pkg/front_end/test/incremental_kernel_generator_test.dart

 // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
 
 import 'package:front_end/compiler_options.dart';
 import 'package:front_end/incremental_kernel_generator.dart';
 import 'package:front_end/memory_file_system.dart';
 import 'package:front_end/src/byte_store/byte_store.dart';
@@ skipping 39 matching lines @@
       ..sdkSummary = sdkOutlineUri;
 
     if (setPackages) {
       compilerOptions.packagesFileUri = Uri.parse('file:///test/.packages');
     }
     incrementalKernelGenerator = await IncrementalKernelGenerator
         .newInstance(compilerOptions, entryPoint, watch: watchFn);
     return (await incrementalKernelGenerator.computeDelta()).newProgram;
   }
 
+  test_acceptLastDelta() async {
+    writeFile('/test/.packages', 'test:lib/');
+    String path = '/test/lib/test.dart';
+    Uri uri = writeFile(path, 'var v = 1;');
+
+    await getInitialState(uri);
+    incrementalKernelGenerator.acceptLastDelta();
+
+    // Attempt to accept the second time.
+    expect(() {
+      incrementalKernelGenerator.acceptLastDelta();
+    }, throwsStateError);
+  }
+
   test_compile_chain() async {
     writeFile('/test/.packages', 'test:lib/');
     String aPath = '/test/lib/a.dart';
     String bPath = '/test/lib/b.dart';
     String cPath = '/test/lib/c.dart';
     Uri aUri = writeFile(aPath, 'var a = 1;');
     Uri bUri = writeFile(bPath, r'''
 import 'a.dart';
 var b = a;
 ''');
     Uri cUri = writeFile(cPath, r'''
 import 'a.dart';
 import 'b.dart';
 var c1 = a;
 var c2 = b;
 void main() {}
 ''');
 
     {
       Program program = await getInitialState(cUri);
+      incrementalKernelGenerator.acceptLastDelta();
       _assertLibraryUris(program,
           includes: [aUri, bUri, cUri, Uri.parse('dart:core')]);
       Library library = _getLibrary(program, cUri);
       expect(_getLibraryText(library), r'''
 library;
 import self as self;
 import "dart:core" as core;
 import "./a.dart" as a;
 import "./b.dart" as b;
 
@@ skipping 57 matching lines @@
 import 'c.dart';
 b() {
   c();
 }
 ''');
     Uri cUri = writeFile(cPath, 'c() { print(0); }');
     Uri dUri = writeFile(dPath, 'd() {}');
 
     {
       Program program = await getInitialState(aUri);
+      incrementalKernelGenerator.acceptLastDelta();
       _assertLibraryUris(program,
           includes: [aUri, bUri, cUri, dUri, Uri.parse('dart:core')]);
     }
 
     // Update c.dart and compute the delta.
     // It should include the changed c.dart, plus b.dart and a.dart because VM
     // requires this (because of possible inlining). But d.dart is not on the
     // path from main() to the changed c.dart, so it is not included.
     writeFile(cPath, 'c() { print(1); }');
     incrementalKernelGenerator.invalidate(cUri);
     {
       DeltaProgram delta = await incrementalKernelGenerator.computeDelta();
+      incrementalKernelGenerator.acceptLastDelta();
       Program program = delta.newProgram;
       _assertLibraryUris(program,
           includes: [aUri, bUri, cUri],
           excludes: [dUri, Uri.parse('dart:core')]);
       // While a.dart and b.dart are is included (VM needs them), they were not
       // recompiled, because the change to c.dart was in the function body.
       _assertCompiledUris([cUri]);
     }
   }
 
@@ skipping 44 matching lines @@
     expect(_getLibraryText(library), r'''
 library;
 import self as self;
 import "dart:core" as core;
 import "package:test/a.dart" as a;
 
 static field core::int b = a::a;
 ''');
   }
 
+  test_rejectLastDelta() async {
+    writeFile('/test/.packages', 'test:lib/');
+    String path = '/test/lib/test.dart';
+    Uri uri = writeFile(path, 'var v = 1;');
+
+    // The first delta includes the the library.
+    {
+      Program program = await getInitialState(uri);
+      _assertLibraryUris(program, includes: [uri]);
+      Library library = _getLibrary(program, uri);
+      expect(_getLibraryText(library), contains('core::int v = 1'));
+    }
+
+    // Reject the last delta, so the test library is included again.
+    incrementalKernelGenerator.rejectLastDelta();
+    {
+      var delta = await incrementalKernelGenerator.computeDelta();
+      Program program = delta.newProgram;
+      _assertLibraryUris(program, includes: [uri]);
+    }
+
+    // Attempt to reject the last delta twice.
+    incrementalKernelGenerator.rejectLastDelta();
+    expect(() {
+      incrementalKernelGenerator.rejectLastDelta();
+    }, throwsStateError);
+  }
+
   test_updateEntryPoint() async {
     writeFile('/test/.packages', 'test:lib/');
     String path = '/test/lib/test.dart';
     Uri uri = writeFile(path, r'''
 main() {
   var v = 1;
 }
 ''');
 
     String initialText = r'''
 library;
 import self as self;
 import "dart:core" as core;
 
 static method main() → dynamic {
   core::int v = 1;
 }
 ''';
 
     // Compute the initial state.
     {
       Program program = await getInitialState(uri);
+      incrementalKernelGenerator.acceptLastDelta();
       Library library = _getLibrary(program, uri);
       expect(_getLibraryText(library), initialText);
     }
 
     // Update the entry point library.
     writeFile(path, r'''
 main() {
   var v = 2.3;
 }
 ''');
 
     // We have not invalidated the file, so the delta is empty.
     {
       DeltaProgram delta = await incrementalKernelGenerator.computeDelta();
+      incrementalKernelGenerator.acceptLastDelta();
       expect(delta.newProgram.libraries, isEmpty);
     }
 
     // Invalidate the file, so get the new text.
     incrementalKernelGenerator.invalidate(uri);
     {
       DeltaProgram delta = await incrementalKernelGenerator.computeDelta();
+      incrementalKernelGenerator.acceptLastDelta();
       Program program = delta.newProgram;
       _assertLibraryUris(program, includes: [uri]);
       Library library = _getLibrary(program, uri);
       expect(_getLibraryText(library), r'''
 library;
 import self as self;
 import "dart:core" as core;
 
 static method main() → dynamic {
   core::double v = 2.3;
@@ skipping 19 matching lines @@
       if (used) {
         usedFiles.add(uri);
       } else {
         unusedFiles.add(uri);
       }
       return new Future.value();
     };
 
     {
       await getInitialState(cUri);
+      incrementalKernelGenerator.acceptLastDelta();
       // We use at least c.dart and a.dart now.
       expect(usedFiles, contains(cUri));
       expect(usedFiles, contains(aUri));
       usedFiles.clear();
       expect(unusedFiles, isEmpty);
     }
 
     // Update c.dart to reference also b.dart file.
     writeFile(cPath, r'''
 import 'a.dart';
 import 'b.dart';
 ''');
     incrementalKernelGenerator.invalidate(cUri);
     {
       await incrementalKernelGenerator.computeDelta();
+      incrementalKernelGenerator.acceptLastDelta();
       // The only new file is b.dart now.
       expect(usedFiles, [bUri]);
       usedFiles.clear();
       expect(unusedFiles, isEmpty);
     }
 
     // Update c.dart to stop referencing b.dart file.
     writeFile(cPath, r'''
 import 'a.dart';
 ''');
     incrementalKernelGenerator.invalidate(cUri);
     {
       await incrementalKernelGenerator.computeDelta();
+      incrementalKernelGenerator.acceptLastDelta();
       // No new used files.
       expect(usedFiles, isEmpty);
       // The file b.dart is not used anymore.
       expect(unusedFiles, [bUri]);
       unusedFiles.clear();
     }
   }
 
   test_watch_null() async {
     writeFile('/test/.packages', 'test:lib/');
     String aPath = '/test/lib/a.dart';
     String bPath = '/test/lib/b.dart';
     writeFile(aPath, "");
     Uri bUri = writeFile(bPath, "");
 
     // Set null, as if the watch function is not provided.
     watchFn = null;
 
     await getInitialState(bUri);
+    incrementalKernelGenerator.acceptLastDelta();
 
     // Update b.dart to import a.dart file.
     writeFile(bPath, "import 'a.dart';");
     incrementalKernelGenerator.invalidate(bUri);
     await incrementalKernelGenerator.computeDelta();
 
     // No exception even though the watcher function is null.
   }
 
   /// Write the given [text] of the file with the given [path] into the
@@ skipping 49 matching lines @@
     throw fail('No library found with URI "$uri"');
   }
 
   String _getLibraryText(Library library) {
     StringBuffer buffer = new StringBuffer();
     new Printer(buffer, syntheticNames: new NameSystem())
         .writeLibraryFile(library);
     return buffer.toString();
   }
 }