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TypeCodec (#349)
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@isoos
isoos authored Aug 25, 2024
1 parent d96766e commit dc2140b
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1 change: 1 addition & 0 deletions CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@
- Updated `TypeRegistry`:
- (internal) `encode` and `decode` methods may be asynchronous
- (internal) using `EncodedValue` instead of `EncodeOutput`
- `TypeCodec` interface (may become public) is used for encoding/decoding value by OIDs.

## 3.3.0

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32 changes: 17 additions & 15 deletions lib/src/types/generic_type.dart
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@@ -1,7 +1,6 @@
import 'dart:convert';
import 'dart:typed_data';

import 'package:buffer/buffer.dart';
import 'package:postgres/src/buffer.dart';

import '../types.dart';
Expand Down Expand Up @@ -54,25 +53,28 @@ class GenericType<T extends Object> extends Type<T> {
const GenericType(super.oid);
}

extension GenericTypeExt<T extends Object> on GenericType<T> {
class GenericTypeCodec extends TypeCodec<Object> {
final int oid;

GenericTypeCodec(
this.oid, {
super.encodesNull,
super.decodesNull,
});

@override
EncodedValue encode(TypeCodecContext context, Object? value) {
if (oid != null && oid! > 0) {
final encoder = PostgresBinaryEncoder(oid!);
final bytes = encoder.convert(value, context.encoding);
return EncodedValue(bytes: bytes, isBinary: true);
} else {
const converter = PostgresTextEncoder();
final text = converter.convert(value, escapeStrings: false);
return EncodedValue(
bytes: castBytes(context.encoding.encode(text)), isBinary: false);
}
final encoder = PostgresBinaryEncoder(oid);
final bytes = encoder.convert(value, context.encoding);
return EncodedValue(bytes: bytes, isBinary: true);
}

T? decode(TypeCodecContext context, EncodedValue input) {
@override
Object? decode(TypeCodecContext context, EncodedValue input) {
if (input.isBinary) {
return PostgresBinaryDecoder.convert(context, oid!, input.bytes!) as T?;
return PostgresBinaryDecoder.convert(context, oid, input.bytes!);
} else {
return PostgresTextDecoder.convert(context, oid!, input.bytes!) as T?;
return PostgresTextDecoder.convert(context, oid, input.bytes!);
}
}
}
8 changes: 8 additions & 0 deletions lib/src/types/text_search.dart
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Expand Up @@ -81,7 +81,10 @@ class TsWordPos {

class TsVectorType extends Type<TsVector> {
const TsVectorType() : super(TypeOid.tsvector);
}

class TsVectorTypeCodec extends TypeCodec {
@override
EncodedValue encode(TypeCodecContext context, Object? value) {
final v = value as TsVector;
final writer = context.newPgByteDataWriter();
Expand All @@ -103,6 +106,7 @@ class TsVectorType extends Type<TsVector> {
return EncodedValue(bytes: bytes, isBinary: true);
}

@override
TsVector? decode(TypeCodecContext context, EncodedValue input) {
if (input.isBinary) {
final reader = context.newPgByteDataReader(input.bytes);
Expand Down Expand Up @@ -178,7 +182,10 @@ sealed class TsQuery {

class TsQueryType extends Type<TsQuery> {
const TsQueryType() : super(TypeOid.tsquery);
}

class TsQueryTypeCodec extends TypeCodec {
@override
EncodedValue encode(TypeCodecContext context, Object? value) {
final v = value as TsQuery;
final writer = context.newPgByteDataWriter();
Expand All @@ -189,6 +196,7 @@ class TsQueryType extends Type<TsQuery> {
return EncodedValue(bytes: bytes, isBinary: true);
}

@override
TsQuery decode(TypeCodecContext context, EncodedValue input) {
if (input.isBinary) {
final reader = context.newPgByteDataReader(input.bytes);
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175 changes: 124 additions & 51 deletions lib/src/types/type_registry.dart
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Expand Up @@ -2,18 +2,12 @@ import 'dart:async';
import 'dart:typed_data';

import 'package:buffer/buffer.dart';
import 'package:postgres/src/types/text_search.dart';

import '../exceptions.dart';
import '../types.dart';
import 'generic_type.dart';
import 'text_codec.dart';
import 'text_search.dart';

typedef TypeEncoderFn = FutureOr<EncodedValue?> Function(
TypeCodecContext context, Object? value);

typedef TypeDecoderFn = FutureOr<Object?> Function(
TypeCodecContext context, EncodedValue input);

/// See: https://github.com/postgres/postgres/blob/master/src/include/catalog/pg_type.dat
class TypeOid {
Expand Down Expand Up @@ -129,6 +123,61 @@ final _builtInTypes = <Type>{
Type.tsquery,
};

final _builtInCodecs = <int, TypeCodec>{
TypeOid.character: GenericTypeCodec(TypeOid.character),
TypeOid.name: GenericTypeCodec(TypeOid.name),
TypeOid.text: GenericTypeCodec(TypeOid.text),
TypeOid.varChar: GenericTypeCodec(TypeOid.varChar),
TypeOid.integer: GenericTypeCodec(TypeOid.integer),
TypeOid.smallInteger: GenericTypeCodec(TypeOid.smallInteger),
TypeOid.bigInteger: GenericTypeCodec(TypeOid.bigInteger),
TypeOid.real: GenericTypeCodec(TypeOid.real),
TypeOid.double: GenericTypeCodec(TypeOid.double),
TypeOid.boolean: GenericTypeCodec(TypeOid.boolean),
TypeOid.voidType: GenericTypeCodec(TypeOid.voidType),
TypeOid.time: GenericTypeCodec(TypeOid.time),
TypeOid.timestampWithTimezone:
GenericTypeCodec(TypeOid.timestampWithTimezone),
TypeOid.timestampWithoutTimezone:
GenericTypeCodec(TypeOid.timestampWithoutTimezone),
TypeOid.interval: GenericTypeCodec(TypeOid.interval),
TypeOid.numeric: GenericTypeCodec(TypeOid.numeric),
TypeOid.byteArray: GenericTypeCodec(TypeOid.byteArray),
TypeOid.date: GenericTypeCodec(TypeOid.date),
TypeOid.json: GenericTypeCodec(TypeOid.json, encodesNull: true),
TypeOid.jsonb: GenericTypeCodec(TypeOid.jsonb, encodesNull: true),
TypeOid.uuid: GenericTypeCodec(TypeOid.uuid),
TypeOid.point: GenericTypeCodec(TypeOid.point),
TypeOid.line: GenericTypeCodec(TypeOid.line),
TypeOid.lineSegment: GenericTypeCodec(TypeOid.lineSegment),
TypeOid.box: GenericTypeCodec(TypeOid.box),
TypeOid.polygon: GenericTypeCodec(TypeOid.polygon),
TypeOid.path: GenericTypeCodec(TypeOid.path),
TypeOid.circle: GenericTypeCodec(TypeOid.circle),
TypeOid.booleanArray: GenericTypeCodec(TypeOid.booleanArray),
TypeOid.smallIntegerArray: GenericTypeCodec(TypeOid.smallIntegerArray),
TypeOid.integerArray: GenericTypeCodec(TypeOid.integerArray),
TypeOid.bigIntegerArray: GenericTypeCodec(TypeOid.bigIntegerArray),
TypeOid.textArray: GenericTypeCodec(TypeOid.textArray),
TypeOid.doubleArray: GenericTypeCodec(TypeOid.doubleArray),
TypeOid.dateArray: GenericTypeCodec(TypeOid.dateArray),
TypeOid.timeArray: GenericTypeCodec(TypeOid.timeArray),
TypeOid.timestampArray: GenericTypeCodec(TypeOid.timestampArray),
TypeOid.timestampTzArray: GenericTypeCodec(TypeOid.timestampTzArray),
TypeOid.uuidArray: GenericTypeCodec(TypeOid.uuidArray),
TypeOid.varCharArray: GenericTypeCodec(TypeOid.varCharArray),
TypeOid.jsonbArray: GenericTypeCodec(TypeOid.jsonbArray),
TypeOid.regtype: GenericTypeCodec(TypeOid.regtype),
TypeOid.integerRange: GenericTypeCodec(TypeOid.integerRange),
TypeOid.bigIntegerRange: GenericTypeCodec(TypeOid.bigIntegerRange),
TypeOid.dateRange: GenericTypeCodec(TypeOid.dateRange),
// TypeOid.numrange: GenericTypeCodec(TypeOid.numrange),
TypeOid.timestampRange: GenericTypeCodec(TypeOid.timestampRange),
TypeOid.timestampTzRange: GenericTypeCodec(TypeOid.timestampTzRange),
TypeOid.tsvector: TsVectorTypeCodec(),
TypeOid.tsquery: TsQueryTypeCodec(),
};

final _builtInTypeNames = <String, Type>{
'bigint': Type.bigInteger,
'boolean': Type.boolean,
Expand Down Expand Up @@ -191,12 +240,45 @@ final _builtInTypeNames = <String, Type>{
'_varchar': Type.varCharArray,
};

abstract class TypeCodec<T> {
/// Whether the `null` value is handled as a special case by this codec.
///
/// By default Dart `null` values are encoded as SQL `NULL` values, and
/// [TypeCodec] will not recieve the `null` value on its [encode] method.
///
/// When the flag is set (`true`) the [TypeCodec.encode] will recieve `null`
/// as `input` value.
final bool encodesNull;

/// Whether the SQL `NULL` value is handled as a special case by this codec.
///
/// By default SQL `NULL` values are decoded as Dart `null` values, and
/// [TypeCodec] will not recieve the `null` value on its [decode] method.
///
/// When the flag is set (`true`) the [TypeCodec.decode] will recieve `null`
/// as `input` value ([EncodedValue.bytes] will be `null`).
final bool decodesNull;

TypeCodec({
this.encodesNull = false,
this.decodesNull = false,
});

/// Encodes the [input] value and returns an [EncodedValue] object.
FutureOr<EncodedValue?> encode(TypeCodecContext context, T? input);

/// Decodes the [input] value and returns a Dart value object.
FutureOr<T?> decode(TypeCodecContext context, EncodedValue input);
}

class TypeRegistry {
final _byTypeOid = <int, Type>{};
final _bySubstitutionName = <String, Type>{};
final _codecs = <int, TypeCodec>{};

TypeRegistry() {
_bySubstitutionName.addAll(_builtInTypeNames);
_codecs.addAll(_builtInCodecs);
for (final type in _builtInTypes) {
if (type.oid != null && type.oid! > 0) {
_byTypeOid[type.oid!] = type;
Expand All @@ -214,28 +296,27 @@ extension TypeRegistryExt on TypeRegistry {

Type? resolveSubstitution(String name) => _bySubstitutionName[name];

FutureOr<EncodedValue> encodeValue({
FutureOr<EncodedValue?> encodeValue({
required TypeCodecContext context,
required TypedValue typedValue,
}) {
}) async {
final type = typedValue.type;
final value = typedValue.value;
switch (type) {
case GenericType():
return type.encode(context, value);
case TsVectorType():
return type.encode(context, value);
case TsQueryType():
return type.encode(context, value);
case UnspecifiedType():
final encoded = _textEncoder.tryConvert(value);
if (encoded != null) {
return EncodedValue(
bytes: castBytes(context.encoding.encode(encoded)),
isBinary: false,
);
}
break;
final oid = type.oid;
final codec = oid == null ? null : _codecs[oid];
if (codec != null) {
if (!codec.encodesNull && value == null) {
return null;
}
return await codec.encode(context, value);
} else {
final encoded = _textEncoder.tryConvert(value);
if (encoded != null) {
return EncodedValue(
bytes: castBytes(context.encoding.encode(encoded)),
isBinary: false,
);
}
}
throw PgException("Could not infer type of value '$value'.");
}
Expand All @@ -245,32 +326,24 @@ extension TypeRegistryExt on TypeRegistry {
required TypeCodecContext context,
required int typeOid,
required bool isBinary,
}) {
if (bytes == null) {
return null;
}
final type = resolveOid(typeOid);
final value = EncodedValue(bytes: bytes, isBinary: isBinary);
switch (type) {
case GenericType():
return type.decode(context, value);
case TsVectorType():
return type.decode(context, value);
case TsQueryType():
return type.decode(context, value);
case UnknownType():
return UndecodedBytes(
typeOid: typeOid,
bytes: bytes,
isBinary: isBinary,
encoding: context.encoding,
);
}) async {
final codec = _codecs[typeOid];
if (codec != null) {
if (!codec.decodesNull && bytes == null) {
return null;
}
final value = EncodedValue(bytes: bytes, isBinary: isBinary);
return await codec.decode(context, value);
} else {
if (bytes == null) {
return null;
}
return UndecodedBytes(
typeOid: typeOid,
bytes: bytes,
isBinary: isBinary,
encoding: context.encoding,
);
}
return UndecodedBytes(
typeOid: typeOid,
bytes: bytes,
isBinary: isBinary,
encoding: context.encoding,
);
}
}

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