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• 0.42.3
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• RowDescriptionResponse.java

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com.google.cloud.spanner.pgadapter.wireoutput.RowDescriptionResponse Maven / Gradle / Ivy

// Copyright 2020 Google LLC
//
// Licensed 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.

package com.google.cloud.spanner.pgadapter.wireoutput;

import com.google.api.core.InternalApi;
import com.google.cloud.spanner.Type;
import com.google.cloud.spanner.pgadapter.ConnectionHandler.QueryMode;
import com.google.cloud.spanner.pgadapter.ProxyServer.DataFormat;
import com.google.cloud.spanner.pgadapter.metadata.OptionsMetadata;
import com.google.cloud.spanner.pgadapter.parsers.Parser;
import com.google.cloud.spanner.pgadapter.statements.IntermediateStatement;
import java.io.DataOutputStream;
import java.text.MessageFormat;
import org.postgresql.core.Oid;

/** Sends back qualifier for a row. */
@InternalApi
public class RowDescriptionResponse extends WireOutput {

  private static final int HEADER_LENGTH = 4;
  private static final int FIELD_NUMBER_LENGTH = 2;
  private static final int TABLE_OID_LENGTH = 4;
  private static final int COLUMN_INDEX_LENGTH = 2;
  private static final int DATA_TYPE_OID_LENGTH = 4;
  private static final int DATA_TYPE_SIZE_LENGTH = 2;
  private static final int TYPE_MODIFIER_LENGTH = 4;
  private static final int FORMAT_CODE_LENGTH = 2;
  private static final int NULL_TERMINATOR_LENGTH = 1;

  private static final byte DEFAULT_FLAG = 0;

  private final IntermediateStatement statement;
  private final Type columns;
  private final QueryMode mode;
  private final OptionsMetadata options;
  private final int columnCount;

  public RowDescriptionResponse(
      DataOutputStream output,
      IntermediateStatement statement,
      Type columns,
      OptionsMetadata options,
      QueryMode mode)
      throws Exception {
    super(output, calculateLength(columns));
    this.statement = statement;
    this.columns = columns;
    this.options = options;
    this.mode = mode;
    this.columnCount = columns.getStructFields().size();
  }

  private static int calculateLength(Type columns) {
    int length = HEADER_LENGTH + FIELD_NUMBER_LENGTH;
    for (int column_index = 0; /* columns start at 0 */
        column_index < columns.getStructFields().size();
        column_index++) {
      length +=
          columns.getStructFields().get(column_index).getName().length()
              + NULL_TERMINATOR_LENGTH
              + TABLE_OID_LENGTH
              + COLUMN_INDEX_LENGTH
              + DATA_TYPE_OID_LENGTH
              + DATA_TYPE_SIZE_LENGTH
              + TYPE_MODIFIER_LENGTH
              + FORMAT_CODE_LENGTH;
    }
    return length;
  }

  @Override
  protected void sendPayload() throws Exception {
    this.outputStream.writeShort(this.columnCount);
    DataFormat defaultFormat = DataFormat.getDataFormat(0, this.statement, this.mode, this.options);
    for (int columnIndex = 0; /* columns start at 0 */
        columnIndex < this.columnCount;
        columnIndex++) {
      this.outputStream.write(
          this.columns.getStructFields().get(columnIndex).getName().getBytes(UTF8));
      // If it can be identified as a column of a table, the object ID of the table.
      this.outputStream.writeByte(DEFAULT_FLAG);
      // If it can be identified as a column of a table, the attribute number of the column
      this.outputStream.writeInt(DEFAULT_FLAG);
      // The object ID of the field's data type.
      this.outputStream.writeShort(DEFAULT_FLAG);
      int oidType = getOidType(columnIndex);
      this.outputStream.writeInt(oidType);
      this.outputStream.writeShort(getOidTypeSize(oidType));
      // The type modifier. The meaning of the modifier is type-specific.
      // No modifier is indicated by -1.
      this.outputStream.writeInt(-1);
      short format =
          this.statement == null
              ? defaultFormat.getCode()
              : this.statement.getResultFormatCode(columnIndex);
      this.outputStream.writeShort(format);
    }
  }

  @Override
  public byte getIdentifier() {
    return 'T';
  }

  @Override
  protected String getMessageName() {
    return "Row Description";
  }

  @Override
  protected String getPayloadString() {
    return new MessageFormat("Length: {0}, " + "Columns Returned: {1}")
        .format(
            new Object[] {
              this.length, this.columnCount,
            });
  }

  int getOidType(int columnIndex) {
    try {
      Type type = this.columns.getStructFields().get(columnIndex).getType();
      return Parser.toOid(type);
    } catch (Exception ignored) {
      return Oid.UNSPECIFIED;
    }
  }

  int getOidTypeSize(int oid_type) {
    switch (oid_type) {
      case Oid.INT2:
        return 2;
      case Oid.INT4:
        return 4;
      case Oid.INT8:
        return 8;
      case Oid.FLOAT4:
        return 4;
      case Oid.FLOAT8:
        return 8;
      case Oid.CHAR:
        return 1;
      case Oid.BOOL:
        return 1;
      case Oid.DATE:
        return 8;
      case Oid.TIME:
        return 8;
      case Oid.TIMESTAMPTZ:
        return 12;
      case Oid.NUMERIC:
      case Oid.TEXT:
      case Oid.VARCHAR:
      case Oid.BYTEA:
      case Oid.JSONB:
      default:
        return -1;
    }
  }
}