Implement a garbage collection prologue and epilogue callback mechanism.

runtime/vm/dart_api_impl_test.cc

 // Copyright (c) 2012, 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.
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_api_state.h"
@@ skipping 1628 matching lines @@
 
     Isolate::Current()->heap()->CollectGarbage(Heap::kOld);
   }
 
   // All weak references except weak3 should be preserved.
   EXPECT(!Dart_IsNull(weak1));
   EXPECT(!Dart_IsNull(weak2));
   EXPECT(Dart_IsNull(weak3));
 }
 
+
+static int global_prologue_callback_status = 0;
+
+
+static void PrologueCallbackTimes2() {
+  global_prologue_callback_status *= 2;
+}
+
+
+static void PrologueCallbackTimes3() {
+  global_prologue_callback_status *= 3;
+}
+
+
+static int global_epilogue_callback_status = 0;
+
+
+static void EpilogueCallbackTimes4() {
+  global_epilogue_callback_status *= 4;

[turnidge, 2012/03/07 00:25:16]

How about relatively prime numbers?  4 -> 5, 5 -> 7.  :-)

Makes sure that 2 callback hasn't been called twice...

[cshapiro, 2012/03/07 03:06:10]

I think I avoid this case by separating the value the time 2 and times 4
operations operate on.  Let me know if I am missing something.

+}
+
+
+static void EpilogueCallbackTimes5() {
+  global_epilogue_callback_status *= 5;
+}
+
+
+TEST_CASE(GarbageCollectionCallbacks) {

[turnidge, 2012/03/07 00:25:16]

Consider splitting into a few smaller tests.

I like the level of coverage.

[cshapiro, 2012/03/07 03:06:10]

Done.

+  // Add a prologue callback.
+  EXPECT_VALID(Dart_NewGcPrologueCallback(&PrologueCallbackTimes2));
+
+  // Add the same prologue callback again.  This is an error.
+  EXPECT(Dart_IsError(Dart_NewGcPrologueCallback(&PrologueCallbackTimes2)));
+
+  // Garbage collect new space.  This should not invoke the prologue
+  // callback.  No status values should change.
+  global_prologue_callback_status = 3;
+  global_epilogue_callback_status = 7;
+  Isolate::Current()->heap()->CollectGarbage(Heap::kNew);
+  EXPECT_EQ(3, global_prologue_callback_status);
+  EXPECT_EQ(7, global_epilogue_callback_status);
+
+  // Garbage collect old space.  This should invoke the prologue
+  // callback.  The prologue status value should change.
+  Isolate::Current()->heap()->CollectGarbage(Heap::kOld);
+  EXPECT_EQ(6, global_prologue_callback_status);
+  EXPECT_EQ(7, global_epilogue_callback_status);
+
+  // Garbage collect old space again.  Callbacks are persistent so the
+  // prolog status value should change again.
+  Isolate::Current()->heap()->CollectGarbage(Heap::kOld);
+  EXPECT_EQ(12, global_prologue_callback_status);
+  EXPECT_EQ(7, global_epilogue_callback_status);
+
+  // Add an GC epilogue callback.
+  EXPECT_VALID(Dart_NewGcEpilogueCallback(&EpilogueCallbackTimes4));
+
+  // Add the same epilogue callback again.  This is an error.
+  EXPECT(Dart_IsError(Dart_NewGcEpilogueCallback(&EpilogueCallbackTimes4)));
+
+  // Garbage collect new space.  This should not invoke the prologue
+  // or the epilogue callback.  No status values should change.
+  global_prologue_callback_status = 3;
+  global_epilogue_callback_status = 7;
+  Isolate::Current()->heap()->CollectGarbage(Heap::kNew);
+  EXPECT_EQ(3, global_prologue_callback_status);
+  EXPECT_EQ(7, global_epilogue_callback_status);
+
+  // Garbage collect old space.  This should invoke the prologue and
+  // the epilogue callbacks.  The prologue and epilogue status values
+  // should change.
+  Isolate::Current()->heap()->CollectGarbage(Heap::kOld);
+  EXPECT_EQ(6, global_prologue_callback_status);
+  EXPECT_EQ(28, global_epilogue_callback_status);
+
+  // Garbage collect old space again.  Callbacks are persistent so the
+  // prologue and epilogue status values should change again.
+  Isolate::Current()->heap()->CollectGarbage(Heap::kOld);
+  EXPECT_EQ(12, global_prologue_callback_status);
+  EXPECT_EQ(112, global_epilogue_callback_status);
+
+  // Add another GC prologue callback.
+  EXPECT_VALID(Dart_NewGcPrologueCallback(&PrologueCallbackTimes3));
+
+  // Garbage collect old space.  This should invoke both prologue
+  // callbacks and the epilogue callback.  The prologue and epilogue
+  // status values should change.
+  global_prologue_callback_status = 3;
+  global_epilogue_callback_status = 7;
+  Isolate::Current()->heap()->CollectGarbage(Heap::kOld);
+  EXPECT_EQ(18, global_prologue_callback_status);
+  EXPECT_EQ(28, global_epilogue_callback_status);
+
+  // Add another GC epilogue callback.
+  EXPECT_VALID(Dart_NewGcEpilogueCallback(&EpilogueCallbackTimes5));
+
+  // Garbage collect old space.  This should invoke both prologue
+  // callbacks and both epilogue callbacks.  The prologue and epilogue
+  // status values should change.
+  global_prologue_callback_status = 3;
+  global_epilogue_callback_status = 7;
+  Isolate::Current()->heap()->CollectGarbage(Heap::kOld);
+  EXPECT_EQ(18, global_prologue_callback_status);
+  EXPECT_EQ(140, global_epilogue_callback_status);
+
+  // Remove an epilogue callback.
+  EXPECT_VALID(Dart_DeleteGcEpilogueCallback(&EpilogueCallbackTimes4));
+
+  // Garbage collect old space.  This should invoke both prologue
+  // callbacks and the remaining epilogue callback.  The prologue and
+  // epilogue status values should change.
+  global_prologue_callback_status = 3;
+  global_epilogue_callback_status = 7;
+  Isolate::Current()->heap()->CollectGarbage(Heap::kOld);
+  EXPECT_EQ(18, global_prologue_callback_status);
+  EXPECT_EQ(35, global_epilogue_callback_status);
+
+  // Try removing the epilogue callback again.  This is an error.
+  EXPECT(Dart_IsError(Dart_DeleteGcEpilogueCallback(&EpilogueCallbackTimes4)));
+
+  // Remove the remaining epilogue callback.
+  EXPECT_VALID(Dart_DeleteGcEpilogueCallback(&EpilogueCallbackTimes5));
+
+  // Try removing the remaining epilogue callback again.  This is an
+  // error.
+  EXPECT(Dart_IsError(Dart_DeleteGcEpilogueCallback(&EpilogueCallbackTimes5)));
+
+  // Garbage collect old space.  This should invoke both prologue
+  // callbacks.  The prologue status value should change.
+  global_prologue_callback_status = 3;
+  global_epilogue_callback_status = 7;
+  Isolate::Current()->heap()->CollectGarbage(Heap::kOld);
+  EXPECT_EQ(18, global_prologue_callback_status);
+  EXPECT_EQ(7, global_epilogue_callback_status);
+
+  // Remove a prologue callback.
+  EXPECT_VALID(Dart_DeleteGcPrologueCallback(&PrologueCallbackTimes3));
+
+  // Try removing the prologue callback again.  This is an error.
+  EXPECT(Dart_IsError(Dart_DeleteGcPrologueCallback(&PrologueCallbackTimes3)));
+
+  // Garbage collect old space.  This should invoke the remaining
+  // prologue callback.  The prologue status value should change.
+  global_prologue_callback_status = 3;
+  global_epilogue_callback_status = 7;
+  Isolate::Current()->heap()->CollectGarbage(Heap::kOld);
+  EXPECT_EQ(6, global_prologue_callback_status);
+  EXPECT_EQ(7, global_epilogue_callback_status);
+
+  // Remove the remaining prologue callback.
+  EXPECT_VALID(Dart_DeleteGcPrologueCallback(&PrologueCallbackTimes2));
+
+  // Try removing the remaining prologue callback again.  This is an
+  // error.
+  EXPECT(Dart_IsError(Dart_DeleteGcPrologueCallback(&PrologueCallbackTimes2)));
+
+  // Garbage collect old space.  No callbacks should be invoked.  No
+  // status values should change.
+  global_prologue_callback_status = 3;
+  global_epilogue_callback_status = 7;
+  Isolate::Current()->heap()->CollectGarbage(Heap::kOld);
+  EXPECT_EQ(3, global_prologue_callback_status);
+  EXPECT_EQ(7, global_epilogue_callback_status);
+}
+
 #endif
 
 
 // Unit test for creating multiple scopes and local handles within them.
 // Ensure that the local handles get all cleaned out when exiting the
 // scope.
 UNIT_TEST_CASE(LocalHandles) {
   TestCase::CreateTestIsolate();
   Isolate* isolate = Isolate::Current();
   EXPECT(isolate != NULL);
@@ skipping 2343 matching lines @@
   // We should have received the expected number of interrupts.
   EXPECT_EQ(kInterruptCount, interrupt_count);
 
   // Give the spawned thread enough time to properly exit.
   Isolate::SetInterruptCallback(saved);
 }
 
 #endif  // defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64).
 
 }  // namespace dart