Provide ability to patch external functions in a class that has already been finalized. The follow…

runtime/vm/dart_api_impl_test.cc

Index: runtime/vm/dart_api_impl_test.cc
diff --git a/runtime/vm/dart_api_impl_test.cc b/runtime/vm/dart_api_impl_test.cc
index 2bda3205765245de180e0814cb5f0ba69d1a73b3..6cbf9f304bcb0e9fffca1b619ae1ee4a76c99630 100644
--- a/runtime/vm/dart_api_impl_test.cc
+++ b/runtime/vm/dart_api_impl_test.cc
@@ -3,6 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 #include "bin/builtin.h"
+#include "vm/compiler.h"
 #include "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
@@ -9853,6 +9854,164 @@ TEST_CASE(Timeline_Dart_EmbedderTimelineStartStopRecording) {
   EXPECT(stop_called);
 }
 
+
+TEST_CASE(Dart_LoadLibraryPatch_1) {
+  const char* kScriptChars1 =
+      "class A {\n"
+      "  int foo() { return 10; }\n"
+      "  external int zoo();\n"
+      "  external static int moo();\n"
+      "}\n"
+      "main() { new A().foo(); }\n"
+      "foozoo() { new A().zoo(); }\n"
+      "foomoo() { A.moo(); }\n";
+
+  const char* kScriptChars2 =
+      "patch class A {\n"
+      "  /* patch */ int zoo() { return 1; }\n"
+      "  /* patch */ static int moo() { return 1; }\n"
+      "}\n";
+
+  Dart_Handle lib = TestCase::LoadTestScript(kScriptChars1, NULL);
+  Dart_Handle result = Dart_Invoke(lib,
+                                   NewString("main"),
+                                   0,
+                                   NULL);
+  EXPECT_VALID(result);
+  Dart_Handle url = NewString("test-lib-patch");
+  Dart_Handle source = NewString(kScriptChars2);
+  result = Dart_LibraryLoadPatch(lib, url, source);
+  EXPECT_VALID(result);
+  result = Dart_FinalizeLoading(false);
+  EXPECT_VALID(result);
+  result = Dart_Invoke(lib,
+                       NewString("foozoo"),
+                       0,
+                       NULL);
+  EXPECT_VALID(result);
+  result = Dart_Invoke(lib,
+                       NewString("foomoo"),
+                       0,
+                       NULL);
+  EXPECT_VALID(result);
+}
+
+
+TEST_CASE(Dart_LoadLibraryPatch_Error1) {
+  const char* kScriptChars1 =
+      "class A {\n"
+      "  int foo() { return 10; }\n"
+      "  external int zoo();\n"
+      "}\n"
+      "main() { new A().foo(); }\n"
+      "foozoo() { new A().zoo(); }\n";
+
+  const char* kScriptChars2 =
+      "patch class A {\n"
+      "  /* patch */ int zoo() { return 1; }\n"
+      "  /* patch */ int fld1;\n"
+      "}\n";
+
+  Dart_Handle lib = TestCase::LoadTestScript(kScriptChars1, NULL);
+  Dart_Handle result = Dart_Invoke(lib,
+                                   NewString("main"),
+                                   0,
+                                   NULL);
+  EXPECT_VALID(result);
+  Dart_Handle url = NewString("test-lib-patch");
+  Dart_Handle source = NewString(kScriptChars2);
+  // We don't expect to be able to patch in this case as new fields
+  // are being added.
+  result = Dart_LibraryLoadPatch(lib, url, source);
+  EXPECT_VALID(result);
+  result = Dart_FinalizeLoading(false);
+  EXPECT_VALID(result);
+  result = Dart_Invoke(lib,
+                       NewString("foozoo"),
+                       0,
+                       NULL);
+  EXPECT(Dart_IsError(result));
+}
+
+
+TEST_CASE(Dart_LoadLibraryPatch_Error2) {
+  const char* kScriptChars1 =
+      "class A {\n"
+      "  int foo() { return 10; }\n"
+      "  int zoo() { return 20; }\n"
+      "}\n"
+      "main() { new A().foo(); }\n"
+      "foozoo() { new A().zoo(); }\n";
+
+  const char* kScriptChars2 =
+      "patch class A {\n"
+      "  /* patch */ int zoo() { return 1; }\n"
+      "}\n";
+
+  Dart_Handle lib = TestCase::LoadTestScript(kScriptChars1, NULL);
+  Dart_Handle result = Dart_Invoke(lib,
+                                   NewString("main"),
+                                   0,
+                                   NULL);
+  EXPECT_VALID(result);
+  Dart_Handle url = NewString("test-lib-patch");
+  Dart_Handle source = NewString(kScriptChars2);
+  // We don't expect to be able to patch in this case as a non external
+  // method is being patched.
+  result = Dart_LibraryLoadPatch(lib, url, source);
+  EXPECT_VALID(result);
+  result = Dart_FinalizeLoading(false);
+  EXPECT_VALID(result);
+  result = Dart_Invoke(lib,
+                       NewString("foozoo"),
+                       0,
+                       NULL);
+  EXPECT(Dart_IsError(result));
+  OS::Print("Patched class executed\n");
+}
+
+
+TEST_CASE(Dart_LoadLibraryPatch_Error3) {
+  const char* kScriptChars1 =
+      "class A {\n"
+      "  int foo() { return 10; }\n"
+      "  external int zoo();\n"
+      "}\n"
+      "main() { new A().foo(); }\n"
+      "foozoo() { new A().zoo(); }\n";
+
+  const char* kScriptChars2 =
+      "patch class A {\n"
+      "  /* patch */ int zoo() { return 1; }\n"
+      "}\n";
+
+  Dart_Handle lib = TestCase::LoadTestScript(kScriptChars1, NULL);
+  Dart_Handle result = Dart_Invoke(lib,
+                                   NewString("main"),
+                                   0,
+                                   NULL);
+  // We invoke the foozoo method to ensure that code for 'zoo' is generated
+  // which throws NoSuchMethod.
+  result = Dart_Invoke(lib,
+                       NewString("foozoo"),
+                       0,
+                       NULL);
+  EXPECT(Dart_IsError(result));
+  Dart_Handle url = NewString("test-lib-patch");
+  Dart_Handle source = NewString(kScriptChars2);
+  // We don't expect to be able to patch in this case as the function being
+  // patched has already executed.
+  result = Dart_LibraryLoadPatch(lib, url, source);
+  EXPECT_VALID(result);
+  result = Dart_FinalizeLoading(false);
+  EXPECT_VALID(result);
+  result = Dart_Invoke(lib,
+                       NewString("foozoo"),
+                       0,
+                       NULL);
+  EXPECT(Dart_IsError(result));
+}
+
 #endif  // !PRODUCT
 
 }  // namespace dart