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author | Feng Xiao <xfxyjwf@gmail.com> | 2015-06-17 13:12:11 -0700 |
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committer | Feng Xiao <xfxyjwf@gmail.com> | 2015-06-17 13:12:11 -0700 |
commit | e9a122eb19ec54dbca15da80355ed0c17cada9b1 (patch) | |
tree | fac37489873ccf47777b2e652db580f9315d7bc7 /src/google/protobuf/util/internal/structured_objectwriter.h | |
parent | b36395b2bac88f70070544c325bc09234cb1f1a6 (diff) | |
parent | 818c5eee08840355d70d2f3bdf1a2f17986a5e70 (diff) | |
download | protobuf-e9a122eb19ec54dbca15da80355ed0c17cada9b1.tar.gz protobuf-e9a122eb19ec54dbca15da80355ed0c17cada9b1.tar.bz2 protobuf-e9a122eb19ec54dbca15da80355ed0c17cada9b1.zip |
Merge pull request #501 from xfxyjwf/down
Down-integrate from internal code base.
Diffstat (limited to 'src/google/protobuf/util/internal/structured_objectwriter.h')
-rw-r--r-- | src/google/protobuf/util/internal/structured_objectwriter.h | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/src/google/protobuf/util/internal/structured_objectwriter.h b/src/google/protobuf/util/internal/structured_objectwriter.h new file mode 100644 index 00000000..3f065d6b --- /dev/null +++ b/src/google/protobuf/util/internal/structured_objectwriter.h @@ -0,0 +1,118 @@ +// 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 +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (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__ |