1 // Copyright 2017 PDFium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef CORE_FPDFAPI_PARSER_CPDF_OBJECT_WALKER_H_ 6 #define CORE_FPDFAPI_PARSER_CPDF_OBJECT_WALKER_H_ 7 8 #include <memory> 9 #include <stack> 10 11 #include "core/fpdfapi/parser/cpdf_dictionary.h" 12 13 // Walk on all non-null sub-objects in an object in depth, include itself, 14 // like in flat list. 15 class CPDF_ObjectWalker { 16 public: 17 class SubobjectIterator { 18 public: 19 virtual ~SubobjectIterator(); IsStarted()20 bool IsStarted() const { return is_started_; } 21 bool virtual IsFinished() const = 0; 22 const CPDF_Object* Increment(); object()23 const CPDF_Object* object() const { return object_; } 24 25 protected: 26 explicit SubobjectIterator(const CPDF_Object* object); 27 28 virtual const CPDF_Object* IncrementImpl() = 0; 29 virtual void Start() = 0; 30 31 private: 32 const CPDF_Object* object_; 33 bool is_started_ = false; 34 }; 35 36 explicit CPDF_ObjectWalker(const CPDF_Object* root); 37 ~CPDF_ObjectWalker(); 38 39 const CPDF_Object* GetNext(); 40 void SkipWalkIntoCurrentObject(); 41 current_depth()42 size_t current_depth() const { return current_depth_; } GetParent()43 const CPDF_Object* GetParent() const { return parent_object_; } dictionary_key()44 const ByteString& dictionary_key() const { return dict_key_; } 45 46 private: 47 static std::unique_ptr<SubobjectIterator> MakeIterator( 48 const CPDF_Object* object); 49 50 const CPDF_Object* next_object_; 51 const CPDF_Object* parent_object_; 52 53 ByteString dict_key_; 54 size_t current_depth_; 55 56 std::stack<std::unique_ptr<SubobjectIterator>> stack_; 57 }; 58 59 class CPDF_NonConstObjectWalker : public CPDF_ObjectWalker { 60 public: CPDF_NonConstObjectWalker(CPDF_Object * root)61 explicit CPDF_NonConstObjectWalker(CPDF_Object* root) 62 : CPDF_ObjectWalker(root) {} 63 GetNext()64 CPDF_Object* GetNext() { 65 return const_cast<CPDF_Object*>(CPDF_ObjectWalker::GetNext()); 66 } 67 }; 68 69 #endif // CORE_FPDFAPI_PARSER_CPDF_OBJECT_WALKER_H_ 70