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134 lines
4.0 KiB
C++
134 lines
4.0 KiB
C++
// Licensed to the Apache Software Foundation (ASF) under one
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// or more contributor license agreements. See the NOTICE file
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// distributed with this work for additional information
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// regarding copyright ownership. The ASF licenses this file
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// to you under the Apache License, Version 2.0 (the
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// "License"); you may not use this file except in compliance
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// with the License. You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing,
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// software distributed under the License is distributed on an
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// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations
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// under the License.
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// Implement Arrow JSON serialization format
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#pragma once
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#include <memory>
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#include <string>
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#include "arrow/status.h"
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#include "arrow/util/visibility.h"
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namespace arrow {
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class Buffer;
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class MemoryPool;
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class RecordBatch;
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class Schema;
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namespace io {
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class ReadableFile;
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} // namespace io
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namespace ipc {
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namespace internal {
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namespace json {
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/// \class JsonWriter
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/// \brief Write the JSON representation of an Arrow record batch file or stream
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///
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/// This is used for integration testing
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class ARROW_EXPORT JsonWriter {
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public:
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~JsonWriter();
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/// \brief Create a new JSON writer that writes to memory
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///
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/// \param[in] schema the schema of record batches
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/// \param[out] out the returned writer object
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/// \return Status
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static Status Open(const std::shared_ptr<Schema>& schema,
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std::unique_ptr<JsonWriter>* out);
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/// \brief Append a record batch
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Status WriteRecordBatch(const RecordBatch& batch);
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/// \brief Finish the JSON payload and return as a std::string
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///
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/// \param[out] result the JSON as as a std::string
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/// \return Status
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Status Finish(std::string* result);
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private:
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explicit JsonWriter(const std::shared_ptr<Schema>& schema);
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// Hide RapidJSON details from public API
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class JsonWriterImpl;
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std::unique_ptr<JsonWriterImpl> impl_;
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};
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/// \class JsonReader
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/// \brief Read the JSON representation of an Arrow record batch file or stream
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///
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/// This is used for integration testing
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class ARROW_EXPORT JsonReader {
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public:
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~JsonReader();
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/// \brief Create a new JSON reader
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///
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/// \param[in] pool a MemoryPool to use for buffer allocations
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/// \param[in] data a Buffer containing the JSON data
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/// \param[out] reader the returned reader object
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/// \return Status
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static Status Open(MemoryPool* pool, const std::shared_ptr<Buffer>& data,
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std::unique_ptr<JsonReader>* reader);
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/// \brief Create a new JSON reader that uses the default memory pool
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///
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/// \param[in] data a Buffer containing the JSON data
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/// \param[out] reader the returned reader object
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/// \return Status
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static Status Open(const std::shared_ptr<Buffer>& data,
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std::unique_ptr<JsonReader>* reader);
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/// \brief Create a new JSON reader from a file
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///
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/// \param[in] pool a MemoryPool to use for buffer allocations
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/// \param[in] in_file a ReadableFile containing JSON data
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/// \param[out] reader the returned reader object
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/// \return Status
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static Status Open(MemoryPool* pool, const std::shared_ptr<io::ReadableFile>& in_file,
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std::unique_ptr<JsonReader>* reader);
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/// \brief Return the schema read from the JSON
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std::shared_ptr<Schema> schema() const;
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/// \brief Return the number of record batches
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int num_record_batches() const;
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/// \brief Read a particular record batch from the file
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///
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/// \param[in] i the record batch index, does not boundscheck
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/// \param[out] batch the read record batch
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Status ReadRecordBatch(int i, std::shared_ptr<RecordBatch>* batch) const;
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private:
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JsonReader(MemoryPool* pool, const std::shared_ptr<Buffer>& data);
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// Hide RapidJSON details from public API
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class JsonReaderImpl;
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std::unique_ptr<JsonReaderImpl> impl_;
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};
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} // namespace json
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} // namespace internal
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} // namespace ipc
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} // namespace arrow
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