schema.h

//
// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.
#ifndef KUDU_CLIENT_SCHEMA_H
#define KUDU_CLIENT_SCHEMA_H

// NOTE: using stdint.h instead of cstdint because this file is supposed
//       to be processed by a compiler lacking C++11 support.
#include <stdint.h>

#include <cstddef>
#include <string>
#include <vector>

#ifdef KUDU_HEADERS_NO_STUBS
#include "kudu/gutil/port.h"
#else
#include "kudu/client/stubs.h"
#endif

#include "kudu/util/kudu_export.h"
#include "kudu/util/status.h"

namespace kudu {

class ColumnSchema;
struct ColumnSchemaDelta;
class KuduPartialRow;
class Schema;
class Slice;

namespace tools {
class RemoteKsckMaster;
class ReplicaDumper;
}

namespace client {

namespace internal {
class GetTableSchemaRpc;
class LookupRpc;
class MetaCacheEntry;
class WriteRpc;
} // namespace internal

class KuduSchema;
class KuduValue;

class KUDU_EXPORT KuduColumnStorageAttributes {
 public:
  enum EncodingType {
    AUTO_ENCODING = 0,
    PLAIN_ENCODING = 1,
    PREFIX_ENCODING = 2,
    RLE = 4,
    DICT_ENCODING = 5,
    BIT_SHUFFLE = 6,

    GROUP_VARINT = 3
  };

  enum CompressionType {
    DEFAULT_COMPRESSION = 0,
    NO_COMPRESSION = 1,
    SNAPPY = 2,
    LZ4 = 3,
    ZLIB = 4,
  };


  explicit KuduColumnStorageAttributes(
      EncodingType encoding = AUTO_ENCODING,
      CompressionType compression = DEFAULT_COMPRESSION,
      int32_t block_size = 0)
      ATTRIBUTE_DEPRECATED("this constructor will be private in a future release")
      : encoding_(encoding),
        compression_(compression),
        block_size_(block_size) {
  }

  const EncodingType encoding() const {
    return encoding_;
  }

  const CompressionType compression() const {
    return compression_;
  }

  std::string ToString() const;

 private:
  EncodingType encoding_;
  CompressionType compression_;
  int32_t block_size_;
};

class KUDU_EXPORT KuduColumnSchema {
 public:
  enum DataType {
    INT8 = 0,
    INT16 = 1,
    INT32 = 2,
    INT64 = 3,
    STRING = 4,
    BOOL = 5,
    FLOAT = 6,
    DOUBLE = 7,
    BINARY = 8,
    UNIXTIME_MICROS = 9,
    TIMESTAMP = UNIXTIME_MICROS 
  };

  static std::string DataTypeToString(DataType type);

  KuduColumnSchema(const std::string &name,
                   DataType type,
                   bool is_nullable = false,
                   const void* default_value = NULL,
                   KuduColumnStorageAttributes attributes = KuduColumnStorageAttributes())
      ATTRIBUTE_DEPRECATED("use KuduSchemaBuilder instead");

  KuduColumnSchema(const KuduColumnSchema& other);
  ~KuduColumnSchema();

  KuduColumnSchema& operator=(const KuduColumnSchema& other);

  void CopyFrom(const KuduColumnSchema& other);

  bool Equals(const KuduColumnSchema& other) const;

  const std::string& name() const;

  DataType type() const;

  bool is_nullable() const;

 private:
  friend class KuduColumnSpec;
  friend class KuduSchema;
  friend class KuduSchemaBuilder;
  // KuduTableAlterer::Data needs to be a friend. Friending the parent class
  // is transitive to nested classes. See http://tiny.cloudera.com/jwtui
  friend class KuduTableAlterer;

  KuduColumnSchema();

  // Owned.
  ColumnSchema* col_;
};

class KUDU_EXPORT KuduColumnSpec {
 public:
  KuduColumnSpec* Default(KuduValue* value);

  KuduColumnSpec* Compression(KuduColumnStorageAttributes::CompressionType compression);

  KuduColumnSpec* Encoding(KuduColumnStorageAttributes::EncodingType encoding);

  KuduColumnSpec* BlockSize(int32_t block_size);

  KuduColumnSpec* PrimaryKey();

  KuduColumnSpec* NotNull();

  KuduColumnSpec* Nullable();

  KuduColumnSpec* Type(KuduColumnSchema::DataType type);

  KuduColumnSpec* RemoveDefault();

  KuduColumnSpec* RenameTo(const std::string& new_name);

 private:
  class KUDU_NO_EXPORT Data;
  friend class KuduSchemaBuilder;
  friend class KuduTableAlterer;

  // This class should always be owned and deleted by one of its friends,
  // not the user.
  ~KuduColumnSpec();

  explicit KuduColumnSpec(const std::string& col_name);

  Status ToColumnSchema(KuduColumnSchema* col) const;

  Status ToColumnSchemaDelta(ColumnSchemaDelta* col_delta) const;

  Slice DefaultValueAsSlice() const;

  // Owned.
  Data* data_;
};

class KUDU_EXPORT KuduSchemaBuilder {
 public:
  KuduSchemaBuilder();
  ~KuduSchemaBuilder();

  KuduColumnSpec* AddColumn(const std::string& name);

  KuduSchemaBuilder* SetPrimaryKey(const std::vector<std::string>& key_col_names);

  Status Build(KuduSchema* schema);

 private:
  class KUDU_NO_EXPORT Data;
  // Owned.
  Data* data_;
};

class KUDU_EXPORT KuduSchema {
 public:
  KuduSchema();

  KuduSchema(const KuduSchema& other);
  ~KuduSchema();

  KuduSchema& operator=(const KuduSchema& other);
  void CopyFrom(const KuduSchema& other);

  Status Reset(const std::vector<KuduColumnSchema>& columns, int key_columns)
      ATTRIBUTE_DEPRECATED("this method will be removed in a future release")
      WARN_UNUSED_RESULT;

  bool Equals(const KuduSchema& other) const;

  KuduColumnSchema Column(size_t idx) const;

  size_t num_columns() const;

  void GetPrimaryKeyColumnIndexes(std::vector<int>* indexes) const;

  KuduPartialRow* NewRow() const;

 private:
  friend class ClientTest;
  friend class KuduClient;
  friend class KuduScanner;
  friend class KuduScanToken;
  friend class KuduScanTokenBuilder;
  friend class KuduSchemaBuilder;
  friend class KuduTable;
  friend class KuduTableCreator;
  friend class KuduWriteOperation;
  friend class ScanConfiguration;
  friend class internal::GetTableSchemaRpc;
  friend class internal::LookupRpc;
  friend class internal::MetaCacheEntry;
  friend class internal::WriteRpc;
  friend class tools::RemoteKsckMaster;
  friend class tools::ReplicaDumper;

  friend KuduSchema KuduSchemaFromSchema(const Schema& schema);


  // For use by kudu tests.
  explicit KuduSchema(const Schema& schema);

  // Private since we don't want users to rely on the first N columns
  // being the keys.
  size_t num_key_columns() const;

  // Owned.
  Schema* schema_;
};

} // namespace client
} // namespace kudu
#endif // KUDU_CLIENT_SCHEMA_H