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| 1 // Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file |
| 2 // for details. All rights reserved. Use of this source code is governed by a |
| 3 // BSD-style license that can be found in the LICENSE file. |
| 4 |
| 5 #ifndef VM_OBJECT_GRAPH_H_ |
| 6 #define VM_OBJECT_GRAPH_H_ |
| 7 |
| 8 #include "vm/object.h" |
| 9 |
| 10 namespace dart { |
| 11 |
| 12 class Isolate; |
| 13 |
| 14 // Utility to traverse the object graph in an ordered fashion. |
| 15 // Example uses: |
| 16 // - find a retaining path from the isolate roots to a particular object, or |
| 17 // - determine how much memory is retained by some particular object(s). |
| 18 class ObjectGraph { |
| 19 public: |
| 20 class Stack; |
| 21 |
| 22 // Allows climbing the search tree all the way to the root. |
| 23 class StackIterator { |
| 24 public: |
| 25 // The object this iterator currently points to. |
| 26 RawObject* Get() const; |
| 27 // Returns false if there is no parent. |
| 28 bool MoveToParent(); |
| 29 private: |
| 30 StackIterator(const Stack* stack, intptr_t index) |
| 31 : stack_(stack), index_(index) { } |
| 32 const Stack* stack_; |
| 33 intptr_t index_; |
| 34 friend class ObjectGraph::Stack; |
| 35 DISALLOW_IMPLICIT_CONSTRUCTORS(StackIterator); |
| 36 }; |
| 37 |
| 38 class Visitor { |
| 39 public: |
| 40 // Directs how the search should continue after visiting an object. |
| 41 enum Direction { |
| 42 kProceed, // Recurse on this object's pointers. |
| 43 kBacktrack, // Ignore this object's pointers. |
| 44 kAbort, // Terminate the entire search immediately. |
| 45 }; |
| 46 virtual ~Visitor() { } |
| 47 // Visits the object pointed to by *it. The iterator is only valid |
| 48 // during this call. This method must not allocate from the heap. |
| 49 virtual Direction VisitObject(StackIterator* it) = 0; |
| 50 }; |
| 51 |
| 52 // No GC is allowed during the lifetime of an ObjectGraph instance. |
| 53 explicit ObjectGraph(Isolate* isolate); |
| 54 ~ObjectGraph(); |
| 55 |
| 56 // Visits all strongly reachable objects in the isolate's heap, in a |
| 57 // pre-order, depth first traversal. |
| 58 void IterateObjects(Visitor* visitor); |
| 59 |
| 60 // Like 'IterateObjects', but restricted to objects reachable from 'root' |
| 61 // (including 'root' itself). |
| 62 void IterateObjectsFrom(const Object& root, Visitor* visitor); |
| 63 |
| 64 private: |
| 65 Isolate* isolate_; |
| 66 DISALLOW_IMPLICIT_CONSTRUCTORS(ObjectGraph); |
| 67 }; |
| 68 |
| 69 } // namespace dart |
| 70 |
| 71 #endif // VM_OBJECT_GRAPH_H_ |
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