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Reactive Relational Database Connectivity Driver Implementation for Postgresql
/*
* Copyright 2019-2020 the original author or authors.
*
* 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
*
* https://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 io.r2dbc.postgresql.codec;
import io.netty.buffer.ByteBuf;
import io.r2dbc.postgresql.message.Format;
import io.r2dbc.postgresql.type.PostgresqlObjectId;
import io.r2dbc.postgresql.util.Assert;
import io.r2dbc.postgresql.util.ByteBufUtils;
import reactor.util.annotation.Nullable;
import java.math.BigDecimal;
import java.util.EnumSet;
import java.util.Set;
import java.util.function.Function;
import static io.r2dbc.postgresql.message.Format.FORMAT_BINARY;
import static io.r2dbc.postgresql.type.PostgresqlObjectId.FLOAT4;
import static io.r2dbc.postgresql.type.PostgresqlObjectId.FLOAT8;
import static io.r2dbc.postgresql.type.PostgresqlObjectId.INT2;
import static io.r2dbc.postgresql.type.PostgresqlObjectId.INT4;
import static io.r2dbc.postgresql.type.PostgresqlObjectId.INT8;
import static io.r2dbc.postgresql.type.PostgresqlObjectId.NUMERIC;
import static io.r2dbc.postgresql.type.PostgresqlObjectId.OID;
/**
* Codec to decode all known numeric types.
*
* @param the type that is handled by this {@link Codec}.
*/
abstract class AbstractNumericCodec extends AbstractCodec {
private static final Set SUPPORTED_TYPES = EnumSet.of(INT2, INT4, INT8, FLOAT4, FLOAT8, NUMERIC, OID);
/**
* Create a new {@link AbstractCodec}.
*
* @param type the type handled by this codec
*/
AbstractNumericCodec(Class type) {
super(type);
}
@Override
public boolean canDecode(int dataType, Format format, Class type) {
Assert.requireNonNull(format, "format must not be null");
Assert.requireNonNull(type, "type must not be null");
if (type == Object.class) {
if (PostgresqlObjectId.isValid(dataType) && PostgresqlObjectId.valueOf(dataType) != getDefaultType()) {
return false;
}
}
return super.canDecode(dataType, format, type);
}
@Override
boolean doCanDecode(PostgresqlObjectId type, Format format) {
Assert.requireNonNull(type, "type must not be null");
Assert.requireNonNull(format, "format must not be null");
return SUPPORTED_TYPES.contains(type);
}
/**
* Decode {@code buffer} to {@link Number} and potentially convert it to {@link Class expectedType} using {@link Function converter} if the decoded type does not match {@code expectedType}.
*
* @param buffer the data buffer
* @param dataType the well-known {@link PostgresqlObjectId type OID}
* @param format the data type {@link Format}, text or binary
* @param expectedType the expected result type
* @param converter the converter function to convert from {@link Number} to {@code expectedType}
* @return the decoded number
*/
T decodeNumber(ByteBuf buffer, PostgresqlObjectId dataType, @Nullable Format format, Class expectedType, Function converter) {
Number number = decodeNumber(buffer, dataType, format);
return potentiallyConvert(number, expectedType, converter);
}
/**
* Decode {@code buffer} to {@link Number} according to {@link PostgresqlObjectId}.
*
* @param buffer the data buffer
* @param dataType the well-known {@link PostgresqlObjectId type OID}
* @param format the data type {@link Format}, text or binary
* @return the decoded number
*/
private Number decodeNumber(ByteBuf buffer, PostgresqlObjectId dataType, @Nullable Format format) {
Assert.requireNonNull(buffer, "byteBuf must not be null");
switch (dataType) {
case NUMERIC:
if (format == FORMAT_BINARY) {
return decodeBinaryBigDecimal(buffer);
}
return new BigDecimal(ByteBufUtils.decode(buffer));
case INT2:
if (FORMAT_BINARY == format) {
return buffer.readShort();
}
return Short.parseShort(ByteBufUtils.decode(buffer));
case INT4:
case OID:
if (FORMAT_BINARY == format) {
return buffer.readInt();
}
return Integer.parseInt(ByteBufUtils.decode(buffer));
case INT8:
if (FORMAT_BINARY == format) {
return buffer.readLong();
}
return Long.parseLong(ByteBufUtils.decode(buffer));
case FLOAT4:
if (FORMAT_BINARY == format) {
return buffer.readFloat();
}
return Float.parseFloat(ByteBufUtils.decode(buffer));
case FLOAT8:
if (FORMAT_BINARY == format) {
return buffer.readDouble();
}
return Double.parseDouble(ByteBufUtils.decode(buffer));
default:
throw new UnsupportedOperationException(String.format("Cannot decode value for type %s, format %s", dataType, format));
}
}
/**
* Returns the {@link PostgresqlObjectId} for to identify whether this codec is the default codec.
*
* @return the {@link PostgresqlObjectId} for to identify whether this codec is the default codec.
*/
abstract PostgresqlObjectId getDefaultType();
private static T potentiallyConvert(Number number, Class expectedType, Function converter) {
return expectedType.isInstance(number) ? expectedType.cast(number) : converter.apply(number);
}
private static BigDecimal decodeBinaryBigDecimal(ByteBuf byteBuf) {
// extract values
short numOfDigits = byteBuf.readShort();
if (numOfDigits == 0) {
return BigDecimal.ZERO;
}
short weight = byteBuf.readShort();
short sign = byteBuf.readShort();
short scale = byteBuf.readShort();
short[] digits = new short[numOfDigits];
for (short i = 0; i < numOfDigits; i++) {
digits[i] = byteBuf.readShort();
}
StringBuilder builder = new StringBuilder();
// whole part
builder.append(digits[0]);
for (short i = 0; i < weight * 4; i++) {
builder.append(0);
}
// decimal part
if (scale > 0) {
builder.append('.');
for (short i = 0; i < scale; i++) {
builder.append(0);
}
}
int expectedLength = builder.length();
int baseOffset = Short.toString(digits[0]).length();
for (short i = 1; i < numOfDigits; i++) {
weight--;
String temp = Short.toString(digits[i]);
int offset = baseOffset + 4 * i - temp.length();
if (weight < 0) {
offset++; // dot between whole and decimal parts
}
builder.replace(offset, offset + temp.length(), temp);
}
builder.setLength(expectedLength); // remove zeros from the end
if (sign == 0) {
return new BigDecimal(builder.toString());
} else {
return new BigDecimal("-" + builder.toString());
}
}
}