diff options
Diffstat (limited to 'vendor/go.mongodb.org/mongo-driver/bson/bsoncodec/registry.go')
-rw-r--r-- | vendor/go.mongodb.org/mongo-driver/bson/bsoncodec/registry.go | 469 |
1 files changed, 469 insertions, 0 deletions
diff --git a/vendor/go.mongodb.org/mongo-driver/bson/bsoncodec/registry.go b/vendor/go.mongodb.org/mongo-driver/bson/bsoncodec/registry.go new file mode 100644 index 000000000..80644023c --- /dev/null +++ b/vendor/go.mongodb.org/mongo-driver/bson/bsoncodec/registry.go @@ -0,0 +1,469 @@ +// 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 + +import ( + "errors" + "fmt" + "reflect" + "sync" + + "go.mongodb.org/mongo-driver/bson/bsontype" +) + +// ErrNilType is returned when nil is passed to either LookupEncoder or LookupDecoder. +var ErrNilType = errors.New("cannot perform a decoder lookup on <nil>") + +// ErrNotPointer is returned when a non-pointer type is provided to LookupDecoder. +var ErrNotPointer = errors.New("non-pointer provided to LookupDecoder") + +// ErrNoEncoder is returned when there wasn't an encoder available for a type. +type ErrNoEncoder struct { + Type reflect.Type +} + +func (ene ErrNoEncoder) Error() string { + if ene.Type == nil { + return "no encoder found for <nil>" + } + return "no encoder found for " + ene.Type.String() +} + +// ErrNoDecoder is returned when there wasn't a decoder available for a type. +type ErrNoDecoder struct { + Type reflect.Type +} + +func (end ErrNoDecoder) Error() string { + return "no decoder found for " + end.Type.String() +} + +// ErrNoTypeMapEntry is returned when there wasn't a type available for the provided BSON type. +type ErrNoTypeMapEntry struct { + Type bsontype.Type +} + +func (entme ErrNoTypeMapEntry) Error() string { + return "no type map entry found for " + entme.Type.String() +} + +// ErrNotInterface is returned when the provided type is not an interface. +var ErrNotInterface = errors.New("The provided type is not an interface") + +// A RegistryBuilder is used to build a Registry. This type is not goroutine +// safe. +type RegistryBuilder struct { + typeEncoders map[reflect.Type]ValueEncoder + interfaceEncoders []interfaceValueEncoder + kindEncoders map[reflect.Kind]ValueEncoder + + typeDecoders map[reflect.Type]ValueDecoder + interfaceDecoders []interfaceValueDecoder + kindDecoders map[reflect.Kind]ValueDecoder + + typeMap map[bsontype.Type]reflect.Type +} + +// A Registry is used to store and retrieve codecs for types and interfaces. This type is the main +// typed passed around and Encoders and Decoders are constructed from it. +type Registry struct { + typeEncoders map[reflect.Type]ValueEncoder + typeDecoders map[reflect.Type]ValueDecoder + + interfaceEncoders []interfaceValueEncoder + interfaceDecoders []interfaceValueDecoder + + kindEncoders map[reflect.Kind]ValueEncoder + kindDecoders map[reflect.Kind]ValueDecoder + + typeMap map[bsontype.Type]reflect.Type + + mu sync.RWMutex +} + +// NewRegistryBuilder creates a new empty RegistryBuilder. +func NewRegistryBuilder() *RegistryBuilder { + return &RegistryBuilder{ + typeEncoders: make(map[reflect.Type]ValueEncoder), + typeDecoders: make(map[reflect.Type]ValueDecoder), + + interfaceEncoders: make([]interfaceValueEncoder, 0), + interfaceDecoders: make([]interfaceValueDecoder, 0), + + kindEncoders: make(map[reflect.Kind]ValueEncoder), + kindDecoders: make(map[reflect.Kind]ValueDecoder), + + typeMap: make(map[bsontype.Type]reflect.Type), + } +} + +func buildDefaultRegistry() *Registry { + rb := NewRegistryBuilder() + defaultValueEncoders.RegisterDefaultEncoders(rb) + defaultValueDecoders.RegisterDefaultDecoders(rb) + return rb.Build() +} + +// RegisterCodec will register the provided ValueCodec for the provided type. +func (rb *RegistryBuilder) RegisterCodec(t reflect.Type, codec ValueCodec) *RegistryBuilder { + rb.RegisterTypeEncoder(t, codec) + rb.RegisterTypeDecoder(t, codec) + return rb +} + +// RegisterTypeEncoder will register the provided ValueEncoder for the provided type. +// +// The type will be used directly, so an encoder can be registered for a type and a different encoder can be registered +// for a pointer to that type. +// +// If the given type is an interface, the encoder will be called when marshalling a type that is that interface. It +// will not be called when marshalling a non-interface type that implements the interface. +func (rb *RegistryBuilder) RegisterTypeEncoder(t reflect.Type, enc ValueEncoder) *RegistryBuilder { + rb.typeEncoders[t] = enc + return rb +} + +// RegisterHookEncoder will register an encoder for the provided interface type t. This encoder will be called when +// marshalling a type if the type implements t or a pointer to the type implements t. If the provided type is not +// an interface (i.e. t.Kind() != reflect.Interface), this method will panic. +func (rb *RegistryBuilder) RegisterHookEncoder(t reflect.Type, enc ValueEncoder) *RegistryBuilder { + if t.Kind() != reflect.Interface { + panicStr := fmt.Sprintf("RegisterHookEncoder expects a type with kind reflect.Interface, "+ + "got type %s with kind %s", t, t.Kind()) + panic(panicStr) + } + + for idx, encoder := range rb.interfaceEncoders { + if encoder.i == t { + rb.interfaceEncoders[idx].ve = enc + return rb + } + } + + rb.interfaceEncoders = append(rb.interfaceEncoders, interfaceValueEncoder{i: t, ve: enc}) + return rb +} + +// RegisterTypeDecoder will register the provided ValueDecoder for the provided type. +// +// The type will be used directly, so a decoder can be registered for a type and a different decoder can be registered +// for a pointer to that type. +// +// If the given type is an interface, the decoder will be called when unmarshalling into a type that is that interface. +// It will not be called when unmarshalling into a non-interface type that implements the interface. +func (rb *RegistryBuilder) RegisterTypeDecoder(t reflect.Type, dec ValueDecoder) *RegistryBuilder { + rb.typeDecoders[t] = dec + return rb +} + +// RegisterHookDecoder will register an decoder for the provided interface type t. This decoder will be called when +// unmarshalling into a type if the type implements t or a pointer to the type implements t. If the provided type is not +// an interface (i.e. t.Kind() != reflect.Interface), this method will panic. +func (rb *RegistryBuilder) RegisterHookDecoder(t reflect.Type, dec ValueDecoder) *RegistryBuilder { + if t.Kind() != reflect.Interface { + panicStr := fmt.Sprintf("RegisterHookDecoder expects a type with kind reflect.Interface, "+ + "got type %s with kind %s", t, t.Kind()) + panic(panicStr) + } + + for idx, decoder := range rb.interfaceDecoders { + if decoder.i == t { + rb.interfaceDecoders[idx].vd = dec + return rb + } + } + + rb.interfaceDecoders = append(rb.interfaceDecoders, interfaceValueDecoder{i: t, vd: dec}) + return rb +} + +// RegisterEncoder registers the provided type and encoder pair. +// +// Deprecated: Use RegisterTypeEncoder or RegisterHookEncoder instead. +func (rb *RegistryBuilder) RegisterEncoder(t reflect.Type, enc ValueEncoder) *RegistryBuilder { + if t == tEmpty { + rb.typeEncoders[t] = enc + return rb + } + switch t.Kind() { + case reflect.Interface: + for idx, ir := range rb.interfaceEncoders { + if ir.i == t { + rb.interfaceEncoders[idx].ve = enc + return rb + } + } + + rb.interfaceEncoders = append(rb.interfaceEncoders, interfaceValueEncoder{i: t, ve: enc}) + default: + rb.typeEncoders[t] = enc + } + return rb +} + +// RegisterDecoder registers the provided type and decoder pair. +// +// Deprecated: Use RegisterTypeDecoder or RegisterHookDecoder instead. +func (rb *RegistryBuilder) RegisterDecoder(t reflect.Type, dec ValueDecoder) *RegistryBuilder { + if t == nil { + rb.typeDecoders[nil] = dec + return rb + } + if t == tEmpty { + rb.typeDecoders[t] = dec + return rb + } + switch t.Kind() { + case reflect.Interface: + for idx, ir := range rb.interfaceDecoders { + if ir.i == t { + rb.interfaceDecoders[idx].vd = dec + return rb + } + } + + rb.interfaceDecoders = append(rb.interfaceDecoders, interfaceValueDecoder{i: t, vd: dec}) + default: + rb.typeDecoders[t] = dec + } + return rb +} + +// RegisterDefaultEncoder will registr the provided ValueEncoder to the provided +// kind. +func (rb *RegistryBuilder) RegisterDefaultEncoder(kind reflect.Kind, enc ValueEncoder) *RegistryBuilder { + rb.kindEncoders[kind] = enc + return rb +} + +// RegisterDefaultDecoder will register the provided ValueDecoder to the +// provided kind. +func (rb *RegistryBuilder) RegisterDefaultDecoder(kind reflect.Kind, dec ValueDecoder) *RegistryBuilder { + rb.kindDecoders[kind] = dec + return rb +} + +// RegisterTypeMapEntry will register the provided type to the BSON type. The primary usage for this +// mapping is decoding situations where an empty interface is used and a default type needs to be +// created and decoded into. +// +// By default, BSON documents will decode into interface{} values as bson.D. To change the default type for BSON +// documents, a type map entry for bsontype.EmbeddedDocument should be registered. For example, to force BSON documents +// to decode to bson.Raw, use the following code: +// +// rb.RegisterTypeMapEntry(bsontype.EmbeddedDocument, reflect.TypeOf(bson.Raw{})) +func (rb *RegistryBuilder) RegisterTypeMapEntry(bt bsontype.Type, rt reflect.Type) *RegistryBuilder { + rb.typeMap[bt] = rt + return rb +} + +// Build creates a Registry from the current state of this RegistryBuilder. +func (rb *RegistryBuilder) Build() *Registry { + registry := new(Registry) + + registry.typeEncoders = make(map[reflect.Type]ValueEncoder) + for t, enc := range rb.typeEncoders { + registry.typeEncoders[t] = enc + } + + registry.typeDecoders = make(map[reflect.Type]ValueDecoder) + for t, dec := range rb.typeDecoders { + registry.typeDecoders[t] = dec + } + + registry.interfaceEncoders = make([]interfaceValueEncoder, len(rb.interfaceEncoders)) + copy(registry.interfaceEncoders, rb.interfaceEncoders) + + registry.interfaceDecoders = make([]interfaceValueDecoder, len(rb.interfaceDecoders)) + copy(registry.interfaceDecoders, rb.interfaceDecoders) + + registry.kindEncoders = make(map[reflect.Kind]ValueEncoder) + for kind, enc := range rb.kindEncoders { + registry.kindEncoders[kind] = enc + } + + registry.kindDecoders = make(map[reflect.Kind]ValueDecoder) + for kind, dec := range rb.kindDecoders { + registry.kindDecoders[kind] = dec + } + + registry.typeMap = make(map[bsontype.Type]reflect.Type) + for bt, rt := range rb.typeMap { + registry.typeMap[bt] = rt + } + + return registry +} + +// LookupEncoder inspects the registry for an encoder for the given type. The lookup precedence works as follows: +// +// 1. An encoder registered for the exact type. If the given type represents an interface, an encoder registered using +// RegisterTypeEncoder for the interface will be selected. +// +// 2. An encoder registered using RegisterHookEncoder for an interface implemented by the type or by a pointer to the +// type. +// +// 3. An encoder registered for the reflect.Kind of the value. +// +// If no encoder is found, an error of type ErrNoEncoder is returned. +func (r *Registry) LookupEncoder(t reflect.Type) (ValueEncoder, error) { + encodererr := ErrNoEncoder{Type: t} + r.mu.RLock() + enc, found := r.lookupTypeEncoder(t) + r.mu.RUnlock() + if found { + if enc == nil { + return nil, ErrNoEncoder{Type: t} + } + return enc, nil + } + + enc, found = r.lookupInterfaceEncoder(t, true) + if found { + r.mu.Lock() + r.typeEncoders[t] = enc + r.mu.Unlock() + return enc, nil + } + + if t == nil { + r.mu.Lock() + r.typeEncoders[t] = nil + r.mu.Unlock() + return nil, encodererr + } + + enc, found = r.kindEncoders[t.Kind()] + if !found { + r.mu.Lock() + r.typeEncoders[t] = nil + r.mu.Unlock() + return nil, encodererr + } + + r.mu.Lock() + r.typeEncoders[t] = enc + r.mu.Unlock() + return enc, nil +} + +func (r *Registry) lookupTypeEncoder(t reflect.Type) (ValueEncoder, bool) { + enc, found := r.typeEncoders[t] + return enc, found +} + +func (r *Registry) lookupInterfaceEncoder(t reflect.Type, allowAddr bool) (ValueEncoder, bool) { + if t == nil { + return nil, false + } + for _, ienc := range r.interfaceEncoders { + if t.Implements(ienc.i) { + return ienc.ve, true + } + if allowAddr && t.Kind() != reflect.Ptr && reflect.PtrTo(t).Implements(ienc.i) { + // if *t implements an interface, this will catch if t implements an interface further ahead + // in interfaceEncoders + defaultEnc, found := r.lookupInterfaceEncoder(t, false) + if !found { + defaultEnc = r.kindEncoders[t.Kind()] + } + return newCondAddrEncoder(ienc.ve, defaultEnc), true + } + } + return nil, false +} + +// LookupDecoder inspects the registry for an decoder for the given type. The lookup precedence works as follows: +// +// 1. A decoder registered for the exact type. If the given type represents an interface, a decoder registered using +// RegisterTypeDecoder for the interface will be selected. +// +// 2. A decoder registered using RegisterHookDecoder for an interface implemented by the type or by a pointer to the +// type. +// +// 3. A decoder registered for the reflect.Kind of the value. +// +// If no decoder is found, an error of type ErrNoDecoder is returned. +func (r *Registry) LookupDecoder(t reflect.Type) (ValueDecoder, error) { + if t == nil { + return nil, ErrNilType + } + decodererr := ErrNoDecoder{Type: t} + r.mu.RLock() + dec, found := r.lookupTypeDecoder(t) + r.mu.RUnlock() + if found { + if dec == nil { + return nil, ErrNoDecoder{Type: t} + } + return dec, nil + } + + dec, found = r.lookupInterfaceDecoder(t, true) + if found { + r.mu.Lock() + r.typeDecoders[t] = dec + r.mu.Unlock() + return dec, nil + } + + dec, found = r.kindDecoders[t.Kind()] + if !found { + r.mu.Lock() + r.typeDecoders[t] = nil + r.mu.Unlock() + return nil, decodererr + } + + r.mu.Lock() + r.typeDecoders[t] = dec + r.mu.Unlock() + return dec, nil +} + +func (r *Registry) lookupTypeDecoder(t reflect.Type) (ValueDecoder, bool) { + dec, found := r.typeDecoders[t] + return dec, found +} + +func (r *Registry) lookupInterfaceDecoder(t reflect.Type, allowAddr bool) (ValueDecoder, bool) { + for _, idec := range r.interfaceDecoders { + if t.Implements(idec.i) { + return idec.vd, true + } + if allowAddr && t.Kind() != reflect.Ptr && reflect.PtrTo(t).Implements(idec.i) { + // if *t implements an interface, this will catch if t implements an interface further ahead + // in interfaceDecoders + defaultDec, found := r.lookupInterfaceDecoder(t, false) + if !found { + defaultDec = r.kindDecoders[t.Kind()] + } + return newCondAddrDecoder(idec.vd, defaultDec), true + } + } + return nil, false +} + +// LookupTypeMapEntry inspects the registry's type map for a Go type for the corresponding BSON +// type. If no type is found, ErrNoTypeMapEntry is returned. +func (r *Registry) LookupTypeMapEntry(bt bsontype.Type) (reflect.Type, error) { + t, ok := r.typeMap[bt] + if !ok || t == nil { + return nil, ErrNoTypeMapEntry{Type: bt} + } + return t, nil +} + +type interfaceValueEncoder struct { + i reflect.Type + ve ValueEncoder +} + +type interfaceValueDecoder struct { + i reflect.Type + vd ValueDecoder +} |