| // Protocol Buffers - Google's data interchange format |
| // Copyright 2008 Google Inc. All rights reserved. |
| // https://developers.google.com/protocol-buffers/ |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following disclaimer |
| // in the documentation and/or other materials provided with the |
| // distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #ifndef GOOGLE_PROTOBUF_UTIL_CONVERTER_STRUCTURED_OBJECTWRITER_H__ |
| #define GOOGLE_PROTOBUF_UTIL_CONVERTER_STRUCTURED_OBJECTWRITER_H__ |
| |
| #include <memory> |
| #ifndef _SHARED_PTR_H |
| #include <google/protobuf/stubs/shared_ptr.h> |
| #endif |
| |
| #include <google/protobuf/stubs/casts.h> |
| #include <google/protobuf/stubs/common.h> |
| #include <google/protobuf/util/internal/object_writer.h> |
| |
| namespace google { |
| namespace protobuf { |
| namespace util { |
| namespace converter { |
| |
| // An StructuredObjectWriter is an ObjectWriter for writing |
| // tree-structured data in a stream of events representing objects |
| // and collections. Implementation of this interface can be used to |
| // write an object stream to an in-memory structure, protobufs, |
| // JSON, XML, or any other output format desired. The ObjectSource |
| // interface is typically used as the source of an object stream. |
| // |
| // See JsonObjectWriter for a sample implementation of |
| // StructuredObjectWriter and its use. |
| // |
| // Derived classes could be thread-unsafe. |
| class LIBPROTOBUF_EXPORT StructuredObjectWriter : public ObjectWriter { |
| public: |
| virtual ~StructuredObjectWriter() {} |
| |
| protected: |
| // A base element class for subclasses to extend, makes tracking state easier. |
| // |
| // StructuredObjectWriter behaves as a visitor. BaseElement represents a node |
| // in the input tree. Implementation of StructuredObjectWriter should also |
| // extend BaseElement to keep track of the location in the input tree. |
| class LIBPROTOBUF_EXPORT BaseElement { |
| public: |
| // Takes ownership of the parent Element. |
| explicit BaseElement(BaseElement* parent) |
| : parent_(parent), level_(parent == NULL ? 0 : parent->level() + 1) {} |
| virtual ~BaseElement() {} |
| |
| // Releases ownership of the parent and returns a pointer to it. |
| template <typename ElementType> |
| ElementType* pop() { |
| return down_cast<ElementType*>(parent_.release()); |
| } |
| |
| // Returns true if this element is the root. |
| bool is_root() const { return parent_ == NULL; } |
| |
| // Returns the number of hops from this element to the root element. |
| int level() const { return level_; } |
| |
| protected: |
| // Returns pointer to parent element without releasing ownership. |
| virtual BaseElement* parent() const { return parent_.get(); } |
| |
| private: |
| // Pointer to the parent Element. |
| google::protobuf::scoped_ptr<BaseElement> parent_; |
| |
| // Number of hops to the root Element. |
| // The root Element has NULL parent_ and a level_ of 0. |
| const int level_; |
| |
| GOOGLE_DISALLOW_IMPLICIT_CONSTRUCTORS(BaseElement); |
| }; |
| |
| StructuredObjectWriter() {} |
| |
| // Returns the current element. Used for indentation and name overrides. |
| virtual BaseElement* element() = 0; |
| |
| private: |
| // Do not add any data members to this class. |
| GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(StructuredObjectWriter); |
| }; |
| |
| } // namespace converter |
| } // namespace util |
| } // namespace protobuf |
| |
| } // namespace google |
| #endif // GOOGLE_PROTOBUF_UTIL_CONVERTER_STRUCTURED_OBJECTWRITER_H__ |