Copied mongo repo (to patch it)

2023-06-18 15:50:55 +02:00
parent 21d241f9b1
commit d471d7c396
544 changed files with 142039 additions and 1 deletions
--- a/mongo/bson/bsoncodec/registry_examples_test.go
+++ b/mongo/bson/bsoncodec/registry_examples_test.go
@@ -0,0 +1,125 @@
+// Copyright (C) MongoDB, Inc. 2017-present.
+//
+// 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
+
+package bsoncodec_test
+
+import (
+	"fmt"
+	"math"
+	"reflect"
+
+	"go.mongodb.org/mongo-driver/bson/bsoncodec"
+	"go.mongodb.org/mongo-driver/bson/bsonrw"
+	"go.mongodb.org/mongo-driver/bson/bsontype"
+)
+
+func ExampleRegistry_customEncoder() {
+	// Write a custom encoder for an integer type that is multiplied by -1 when
+	// encoding.
+
+	// To register the default encoders and decoders in addition to this custom
+	// one, use bson.NewRegistryBuilder instead.
+	rb := bsoncodec.NewRegistryBuilder()
+	type negatedInt int
+
+	niType := reflect.TypeOf(negatedInt(0))
+	encoder := func(
+		ec bsoncodec.EncodeContext,
+		vw bsonrw.ValueWriter,
+		val reflect.Value,
+	) error {
+		// All encoder implementations should check that val is valid and is of
+		// the correct type before proceeding.
+		if !val.IsValid() || val.Type() != niType {
+			return bsoncodec.ValueEncoderError{
+				Name:     "negatedIntEncodeValue",
+				Types:    []reflect.Type{niType},
+				Received: val,
+			}
+		}
+
+		// Negate val and encode as a BSON int32 if it can fit in 32 bits and a
+		// BSON int64 otherwise.
+		negatedVal := val.Int() * -1
+		if math.MinInt32 <= negatedVal && negatedVal <= math.MaxInt32 {
+			return vw.WriteInt32(int32(negatedVal))
+		}
+		return vw.WriteInt64(negatedVal)
+	}
+
+	rb.RegisterTypeEncoder(niType, bsoncodec.ValueEncoderFunc(encoder))
+}
+
+func ExampleRegistry_customDecoder() {
+	// Write a custom decoder for a boolean type that can be stored in the
+	// database as a BSON boolean, int32, int64, double, or null. BSON int32,
+	// int64, and double values are considered "true" in this decoder if they
+	// are non-zero. BSON null values are always considered false.
+
+	// To register the default encoders and decoders in addition to this custom
+	// one, use bson.NewRegistryBuilder instead.
+	rb := bsoncodec.NewRegistryBuilder()
+	type lenientBool bool
+
+	decoder := func(
+		dc bsoncodec.DecodeContext,
+		vr bsonrw.ValueReader,
+		val reflect.Value,
+	) error {
+		// All decoder implementations should check that val is valid, settable,
+		// and is of the correct kind before proceeding.
+		if !val.IsValid() || !val.CanSet() || val.Kind() != reflect.Bool {
+			return bsoncodec.ValueDecoderError{
+				Name:     "lenientBoolDecodeValue",
+				Kinds:    []reflect.Kind{reflect.Bool},
+				Received: val,
+			}
+		}
+
+		var result bool
+		switch vr.Type() {
+		case bsontype.Boolean:
+			b, err := vr.ReadBoolean()
+			if err != nil {
+				return err
+			}
+			result = b
+		case bsontype.Int32:
+			i32, err := vr.ReadInt32()
+			if err != nil {
+				return err
+			}
+			result = i32 != 0
+		case bsontype.Int64:
+			i64, err := vr.ReadInt64()
+			if err != nil {
+				return err
+			}
+			result = i64 != 0
+		case bsontype.Double:
+			f64, err := vr.ReadDouble()
+			if err != nil {
+				return err
+			}
+			result = f64 != 0
+		case bsontype.Null:
+			if err := vr.ReadNull(); err != nil {
+				return err
+			}
+			result = false
+		default:
+			return fmt.Errorf(
+				"received invalid BSON type to decode into lenientBool: %s",
+				vr.Type())
+		}
+
+		val.SetBool(result)
+		return nil
+	}
+
+	lbType := reflect.TypeOf(lenientBool(true))
+	rb.RegisterTypeDecoder(lbType, bsoncodec.ValueDecoderFunc(decoder))
+}