VM service: List all instances of a class.

runtime/vm/service.cc

 // Copyright (c) 2013, 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 "vm/service.h"
 
 #include "include/dart_api.h"
 #include "platform/globals.h"
 
 #include "vm/compiler.h"
 #include "vm/coverage.h"
 #include "vm/cpu.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
 #include "vm/isolate.h"
 #include "vm/message.h"
 #include "vm/message_handler.h"
 #include "vm/native_entry.h"
 #include "vm/native_arguments.h"
 #include "vm/object.h"
 #include "vm/object_graph.h"
 #include "vm/object_id_ring.h"
 #include "vm/object_store.h"
 #include "vm/port.h"
 #include "vm/profiler.h"
+#include "vm/reusable_handles.h"
 #include "vm/stack_frame.h"
 #include "vm/symbols.h"
 #include "vm/version.h"
 
 
 namespace dart {
 
 DEFINE_FLAG(bool, trace_service, false, "Trace VM service requests.");
 DEFINE_FLAG(bool, trace_service_pause_events, false,
             "Trace VM service isolate pause events.");
@@ skipping 1093 matching lines @@
     return true;
   }
   ObjectGraph graph(isolate);
   intptr_t retained_size = graph.SizeRetainedByClass(cls.id());
   const Object& result = Object::Handle(Integer::New(retained_size));
   result.PrintJSON(js, true);
   return true;
 }
 
 
+class GetInstancesVisitor : public ObjectVisitor {
+ public:
+  GetInstancesVisitor(Isolate* isolate, const Class& cls, const Array& storage)
+      : ObjectVisitor(isolate), cls_(cls), storage_(storage), count_(0) {}
+
+  virtual void VisitObject(RawObject* raw_obj) {
+    if (raw_obj->IsFreeListElement()) {
+      return;
+    }
+    REUSABLE_OBJECT_HANDLESCOPE(isolate());
+    Object& obj = isolate()->ObjectHandle();
+    obj = raw_obj;
+    if (obj.GetClassId() == cls_.id()) {
+      if (!storage_.IsNull() && count_ < storage_.Length()) {
+        storage_.SetAt(count_, obj);
+      }
+      ++count_;
+    }
+  }
+
+  intptr_t count() const { return count_; }
+
+ private:
+  const Class& cls_;
+  const Array& storage_;
+  intptr_t count_;
+};
+
+
+static bool HandleClassesInstances(Isolate* isolate, const Class& cls,
+                                   JSONStream* js) {
+  if (js->num_arguments() != 3) {
+    PrintError(js, "Command too long");
+    return true;
+  }
+  intptr_t limit;
+  if (!GetIntegerId(js->LookupOption("limit"), &limit)) {
+    PrintError(js, "instances expects a 'limit' option\n",
+               js->num_arguments());
+    return true;
+  }
+  Array& storage = Array::Handle(Array::New(limit));
+  GetInstancesVisitor visitor(isolate, cls, storage);
+  isolate->heap()->IterateObjects(&visitor);
+  intptr_t count = visitor.count();
+  if (count < limit) {
+    // Truncate the list using utility method for GrowableObjectArray.
+    GrowableObjectArray& wrapper = GrowableObjectArray::Handle(
+        GrowableObjectArray::New(storage));
+    wrapper.SetLength(count);
+    storage = Array::MakeArray(wrapper);
+  }
+  storage.PrintJSON(js, true);
+  return true;
+}
+
+
 static bool HandleClasses(Isolate* isolate, JSONStream* js) {
   if (js->num_arguments() == 1) {
     ClassTable* table = isolate->class_table();
     JSONObject jsobj(js);
     table->PrintToJSONObject(&jsobj);
     return true;
   }
   ASSERT(js->num_arguments() >= 2);
   intptr_t id;
   if (!GetIntegerId(js->GetArgument(1), &id)) {
@@ skipping 16 matching lines @@
     } else if (strcmp(second, "closures") == 0) {
       return HandleClassesClosures(isolate, cls, js);
     } else if (strcmp(second, "fields") == 0) {
       return HandleClassesFields(isolate, cls, js);
     } else if (strcmp(second, "functions") == 0) {
       return HandleClassesFunctions(isolate, cls, js);
     } else if (strcmp(second, "implicit_closures") == 0) {
       return HandleClassesImplicitClosures(isolate, cls, js);
     } else if (strcmp(second, "dispatchers") == 0) {
       return HandleClassesDispatchers(isolate, cls, js);
-    } else if (!strcmp(second, "types")) {
+    } else if (strcmp(second, "types") == 0) {
       return HandleClassesTypes(isolate, cls, js);
-    } else if (!strcmp(second, "retained")) {
+    } else if (strcmp(second, "retained") == 0) {
       return HandleClassesRetained(isolate, cls, js);
+    } else if (strcmp(second, "instances") == 0) {
+      return HandleClassesInstances(isolate, cls, js);
     } else {
       PrintError(js, "Invalid sub collection %s", second);
       return true;
     }
   }
   UNREACHABLE();
   return true;
 }
 
 
@@ skipping 916 matching lines @@
   while (current != NULL) {
     if (strcmp(name, current->name()) == 0) {
       return current;
     }
     current = current->next();
   }
   return NULL;
 }
 
 }  // namespace dart