608 lines
19 KiB
Go
608 lines
19 KiB
Go
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// Go support for Protocol Buffers - Google's data interchange format
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//
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// Copyright 2010 The Go Authors. All rights reserved.
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// https://github.com/golang/protobuf
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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package proto
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/*
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* Types and routines for supporting protocol buffer extensions.
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*/
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import (
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"errors"
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"fmt"
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"io"
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"reflect"
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"strconv"
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"sync"
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)
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// ErrMissingExtension is the error returned by GetExtension if the named extension is not in the message.
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var ErrMissingExtension = errors.New("proto: missing extension")
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// ExtensionRange represents a range of message extensions for a protocol buffer.
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// Used in code generated by the protocol compiler.
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type ExtensionRange struct {
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Start, End int32 // both inclusive
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}
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// extendableProto is an interface implemented by any protocol buffer generated by the current
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// proto compiler that may be extended.
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type extendableProto interface {
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Message
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ExtensionRangeArray() []ExtensionRange
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extensionsWrite() map[int32]Extension
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extensionsRead() (map[int32]Extension, sync.Locker)
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}
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// extendableProtoV1 is an interface implemented by a protocol buffer generated by the previous
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// version of the proto compiler that may be extended.
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type extendableProtoV1 interface {
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Message
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ExtensionRangeArray() []ExtensionRange
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ExtensionMap() map[int32]Extension
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}
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// extensionAdapter is a wrapper around extendableProtoV1 that implements extendableProto.
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type extensionAdapter struct {
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extendableProtoV1
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}
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func (e extensionAdapter) extensionsWrite() map[int32]Extension {
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return e.ExtensionMap()
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}
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func (e extensionAdapter) extensionsRead() (map[int32]Extension, sync.Locker) {
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return e.ExtensionMap(), notLocker{}
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}
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// notLocker is a sync.Locker whose Lock and Unlock methods are nops.
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type notLocker struct{}
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func (n notLocker) Lock() {}
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func (n notLocker) Unlock() {}
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// extendable returns the extendableProto interface for the given generated proto message.
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// If the proto message has the old extension format, it returns a wrapper that implements
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// the extendableProto interface.
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func extendable(p interface{}) (extendableProto, error) {
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switch p := p.(type) {
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case extendableProto:
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if isNilPtr(p) {
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return nil, fmt.Errorf("proto: nil %T is not extendable", p)
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}
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return p, nil
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case extendableProtoV1:
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if isNilPtr(p) {
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return nil, fmt.Errorf("proto: nil %T is not extendable", p)
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}
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return extensionAdapter{p}, nil
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}
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// Don't allocate a specific error containing %T:
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// this is the hot path for Clone and MarshalText.
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return nil, errNotExtendable
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}
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var errNotExtendable = errors.New("proto: not an extendable proto.Message")
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func isNilPtr(x interface{}) bool {
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v := reflect.ValueOf(x)
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return v.Kind() == reflect.Ptr && v.IsNil()
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}
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// XXX_InternalExtensions is an internal representation of proto extensions.
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//
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// Each generated message struct type embeds an anonymous XXX_InternalExtensions field,
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// thus gaining the unexported 'extensions' method, which can be called only from the proto package.
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//
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// The methods of XXX_InternalExtensions are not concurrency safe in general,
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// but calls to logically read-only methods such as has and get may be executed concurrently.
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type XXX_InternalExtensions struct {
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// The struct must be indirect so that if a user inadvertently copies a
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// generated message and its embedded XXX_InternalExtensions, they
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// avoid the mayhem of a copied mutex.
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//
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// The mutex serializes all logically read-only operations to p.extensionMap.
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// It is up to the client to ensure that write operations to p.extensionMap are
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// mutually exclusive with other accesses.
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p *struct {
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mu sync.Mutex
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extensionMap map[int32]Extension
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}
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}
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// extensionsWrite returns the extension map, creating it on first use.
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func (e *XXX_InternalExtensions) extensionsWrite() map[int32]Extension {
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if e.p == nil {
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e.p = new(struct {
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mu sync.Mutex
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extensionMap map[int32]Extension
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})
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e.p.extensionMap = make(map[int32]Extension)
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}
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return e.p.extensionMap
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}
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// extensionsRead returns the extensions map for read-only use. It may be nil.
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// The caller must hold the returned mutex's lock when accessing Elements within the map.
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func (e *XXX_InternalExtensions) extensionsRead() (map[int32]Extension, sync.Locker) {
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if e.p == nil {
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return nil, nil
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}
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return e.p.extensionMap, &e.p.mu
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}
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// ExtensionDesc represents an extension specification.
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// Used in generated code from the protocol compiler.
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type ExtensionDesc struct {
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ExtendedType Message // nil pointer to the type that is being extended
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ExtensionType interface{} // nil pointer to the extension type
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Field int32 // field number
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Name string // fully-qualified name of extension, for text formatting
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Tag string // protobuf tag style
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Filename string // name of the file in which the extension is defined
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}
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func (ed *ExtensionDesc) repeated() bool {
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t := reflect.TypeOf(ed.ExtensionType)
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return t.Kind() == reflect.Slice && t.Elem().Kind() != reflect.Uint8
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}
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// Extension represents an extension in a message.
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type Extension struct {
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// When an extension is stored in a message using SetExtension
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// only desc and value are set. When the message is marshaled
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// enc will be set to the encoded form of the message.
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//
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// When a message is unmarshaled and contains extensions, each
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// extension will have only enc set. When such an extension is
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// accessed using GetExtension (or GetExtensions) desc and value
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// will be set.
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desc *ExtensionDesc
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// value is a concrete value for the extension field. Let the type of
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// desc.ExtensionType be the "API type" and the type of Extension.value
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// be the "storage type". The API type and storage type are the same except:
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// * For scalars (except []byte), the API type uses *T,
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// while the storage type uses T.
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// * For repeated fields, the API type uses []T, while the storage type
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// uses *[]T.
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//
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// The reason for the divergence is so that the storage type more naturally
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// matches what is expected of when retrieving the values through the
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// protobuf reflection APIs.
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//
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// The value may only be populated if desc is also populated.
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value interface{}
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// enc is the raw bytes for the extension field.
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enc []byte
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}
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// SetRawExtension is for testing only.
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func SetRawExtension(base Message, id int32, b []byte) {
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epb, err := extendable(base)
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if err != nil {
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return
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}
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extmap := epb.extensionsWrite()
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extmap[id] = Extension{enc: b}
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}
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// isExtensionField returns true iff the given field number is in an extension range.
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func isExtensionField(pb extendableProto, field int32) bool {
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for _, er := range pb.ExtensionRangeArray() {
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if er.Start <= field && field <= er.End {
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return true
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}
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}
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return false
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}
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// checkExtensionTypes checks that the given extension is valid for pb.
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func checkExtensionTypes(pb extendableProto, extension *ExtensionDesc) error {
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var pbi interface{} = pb
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// Check the extended type.
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if ea, ok := pbi.(extensionAdapter); ok {
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pbi = ea.extendableProtoV1
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}
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if a, b := reflect.TypeOf(pbi), reflect.TypeOf(extension.ExtendedType); a != b {
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return fmt.Errorf("proto: bad extended type; %v does not extend %v", b, a)
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}
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// Check the range.
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if !isExtensionField(pb, extension.Field) {
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return errors.New("proto: bad extension number; not in declared ranges")
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}
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return nil
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}
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// extPropKey is sufficient to uniquely identify an extension.
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type extPropKey struct {
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base reflect.Type
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field int32
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}
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var extProp = struct {
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sync.RWMutex
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m map[extPropKey]*Properties
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}{
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m: make(map[extPropKey]*Properties),
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}
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func extensionProperties(ed *ExtensionDesc) *Properties {
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key := extPropKey{base: reflect.TypeOf(ed.ExtendedType), field: ed.Field}
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extProp.RLock()
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if prop, ok := extProp.m[key]; ok {
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extProp.RUnlock()
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return prop
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}
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extProp.RUnlock()
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extProp.Lock()
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defer extProp.Unlock()
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// Check again.
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if prop, ok := extProp.m[key]; ok {
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return prop
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}
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prop := new(Properties)
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prop.Init(reflect.TypeOf(ed.ExtensionType), "unknown_name", ed.Tag, nil)
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extProp.m[key] = prop
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return prop
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}
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// HasExtension returns whether the given extension is present in pb.
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func HasExtension(pb Message, extension *ExtensionDesc) bool {
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// TODO: Check types, field numbers, etc.?
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epb, err := extendable(pb)
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if err != nil {
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return false
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}
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extmap, mu := epb.extensionsRead()
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if extmap == nil {
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return false
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}
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mu.Lock()
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_, ok := extmap[extension.Field]
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mu.Unlock()
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return ok
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}
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// ClearExtension removes the given extension from pb.
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func ClearExtension(pb Message, extension *ExtensionDesc) {
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epb, err := extendable(pb)
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if err != nil {
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return
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}
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// TODO: Check types, field numbers, etc.?
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extmap := epb.extensionsWrite()
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delete(extmap, extension.Field)
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}
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// GetExtension retrieves a proto2 extended field from pb.
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//
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// If the descriptor is type complete (i.e., ExtensionDesc.ExtensionType is non-nil),
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// then GetExtension parses the encoded field and returns a Go value of the specified type.
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// If the field is not present, then the default value is returned (if one is specified),
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// otherwise ErrMissingExtension is reported.
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//
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// If the descriptor is not type complete (i.e., ExtensionDesc.ExtensionType is nil),
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// then GetExtension returns the raw encoded bytes of the field extension.
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func GetExtension(pb Message, extension *ExtensionDesc) (interface{}, error) {
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epb, err := extendable(pb)
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if err != nil {
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return nil, err
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}
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if extension.ExtendedType != nil {
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// can only check type if this is a complete descriptor
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if err := checkExtensionTypes(epb, extension); err != nil {
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return nil, err
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}
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}
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emap, mu := epb.extensionsRead()
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if emap == nil {
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return defaultExtensionValue(extension)
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}
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mu.Lock()
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defer mu.Unlock()
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e, ok := emap[extension.Field]
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if !ok {
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// defaultExtensionValue returns the default value or
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// ErrMissingExtension if there is no default.
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return defaultExtensionValue(extension)
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}
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if e.value != nil {
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// Already decoded. Check the descriptor, though.
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if e.desc != extension {
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// This shouldn't happen. If it does, it means that
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// GetExtension was called twice with two different
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// descriptors with the same field number.
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return nil, errors.New("proto: descriptor conflict")
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}
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return extensionAsLegacyType(e.value), nil
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}
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if extension.ExtensionType == nil {
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// incomplete descriptor
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return e.enc, nil
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}
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v, err := decodeExtension(e.enc, extension)
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if err != nil {
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return nil, err
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}
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// Remember the decoded version and drop the encoded version.
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// That way it is safe to mutate what we return.
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e.value = extensionAsStorageType(v)
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e.desc = extension
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e.enc = nil
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emap[extension.Field] = e
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return extensionAsLegacyType(e.value), nil
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}
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// defaultExtensionValue returns the default value for extension.
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// If no default for an extension is defined ErrMissingExtension is returned.
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func defaultExtensionValue(extension *ExtensionDesc) (interface{}, error) {
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if extension.ExtensionType == nil {
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// incomplete descriptor, so no default
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return nil, ErrMissingExtension
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}
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t := reflect.TypeOf(extension.ExtensionType)
|
||
|
|
props := extensionProperties(extension)
|
||
|
|
|
||
|
|
sf, _, err := fieldDefault(t, props)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
|
||
|
|
if sf == nil || sf.value == nil {
|
||
|
|
// There is no default value.
|
||
|
|
return nil, ErrMissingExtension
|
||
|
|
}
|
||
|
|
|
||
|
|
if t.Kind() != reflect.Ptr {
|
||
|
|
// We do not need to return a Ptr, we can directly return sf.value.
|
||
|
|
return sf.value, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// We need to return an interface{} that is a pointer to sf.value.
|
||
|
|
value := reflect.New(t).Elem()
|
||
|
|
value.Set(reflect.New(value.Type().Elem()))
|
||
|
|
if sf.kind == reflect.Int32 {
|
||
|
|
// We may have an int32 or an enum, but the underlying data is int32.
|
||
|
|
// Since we can't set an int32 into a non int32 reflect.value directly
|
||
|
|
// set it as a int32.
|
||
|
|
value.Elem().SetInt(int64(sf.value.(int32)))
|
||
|
|
} else {
|
||
|
|
value.Elem().Set(reflect.ValueOf(sf.value))
|
||
|
|
}
|
||
|
|
return value.Interface(), nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// decodeExtension decodes an extension encoded in b.
|
||
|
|
func decodeExtension(b []byte, extension *ExtensionDesc) (interface{}, error) {
|
||
|
|
t := reflect.TypeOf(extension.ExtensionType)
|
||
|
|
unmarshal := typeUnmarshaler(t, extension.Tag)
|
||
|
|
|
||
|
|
// t is a pointer to a struct, pointer to basic type or a slice.
|
||
|
|
// Allocate space to store the pointer/slice.
|
||
|
|
value := reflect.New(t).Elem()
|
||
|
|
|
||
|
|
var err error
|
||
|
|
for {
|
||
|
|
x, n := decodeVarint(b)
|
||
|
|
if n == 0 {
|
||
|
|
return nil, io.ErrUnexpectedEOF
|
||
|
|
}
|
||
|
|
b = b[n:]
|
||
|
|
wire := int(x) & 7
|
||
|
|
|
||
|
|
b, err = unmarshal(b, valToPointer(value.Addr()), wire)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
|
||
|
|
if len(b) == 0 {
|
||
|
|
break
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return value.Interface(), nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// GetExtensions returns a slice of the extensions present in pb that are also listed in es.
|
||
|
|
// The returned slice has the same length as es; missing extensions will appear as nil elements.
|
||
|
|
func GetExtensions(pb Message, es []*ExtensionDesc) (extensions []interface{}, err error) {
|
||
|
|
epb, err := extendable(pb)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
extensions = make([]interface{}, len(es))
|
||
|
|
for i, e := range es {
|
||
|
|
extensions[i], err = GetExtension(epb, e)
|
||
|
|
if err == ErrMissingExtension {
|
||
|
|
err = nil
|
||
|
|
}
|
||
|
|
if err != nil {
|
||
|
|
return
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
// ExtensionDescs returns a new slice containing pb's extension descriptors, in undefined order.
|
||
|
|
// For non-registered extensions, ExtensionDescs returns an incomplete descriptor containing
|
||
|
|
// just the Field field, which defines the extension's field number.
|
||
|
|
func ExtensionDescs(pb Message) ([]*ExtensionDesc, error) {
|
||
|
|
epb, err := extendable(pb)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
registeredExtensions := RegisteredExtensions(pb)
|
||
|
|
|
||
|
|
emap, mu := epb.extensionsRead()
|
||
|
|
if emap == nil {
|
||
|
|
return nil, nil
|
||
|
|
}
|
||
|
|
mu.Lock()
|
||
|
|
defer mu.Unlock()
|
||
|
|
extensions := make([]*ExtensionDesc, 0, len(emap))
|
||
|
|
for extid, e := range emap {
|
||
|
|
desc := e.desc
|
||
|
|
if desc == nil {
|
||
|
|
desc = registeredExtensions[extid]
|
||
|
|
if desc == nil {
|
||
|
|
desc = &ExtensionDesc{Field: extid}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
extensions = append(extensions, desc)
|
||
|
|
}
|
||
|
|
return extensions, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// SetExtension sets the specified extension of pb to the specified value.
|
||
|
|
func SetExtension(pb Message, extension *ExtensionDesc, value interface{}) error {
|
||
|
|
epb, err := extendable(pb)
|
||
|
|
if err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
if err := checkExtensionTypes(epb, extension); err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
typ := reflect.TypeOf(extension.ExtensionType)
|
||
|
|
if typ != reflect.TypeOf(value) {
|
||
|
|
return fmt.Errorf("proto: bad extension value type. got: %T, want: %T", value, extension.ExtensionType)
|
||
|
|
}
|
||
|
|
// nil extension values need to be caught early, because the
|
||
|
|
// encoder can't distinguish an ErrNil due to a nil extension
|
||
|
|
// from an ErrNil due to a missing field. Extensions are
|
||
|
|
// always optional, so the encoder would just swallow the error
|
||
|
|
// and drop all the extensions from the encoded message.
|
||
|
|
if reflect.ValueOf(value).IsNil() {
|
||
|
|
return fmt.Errorf("proto: SetExtension called with nil value of type %T", value)
|
||
|
|
}
|
||
|
|
|
||
|
|
extmap := epb.extensionsWrite()
|
||
|
|
extmap[extension.Field] = Extension{desc: extension, value: extensionAsStorageType(value)}
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// ClearAllExtensions clears all extensions from pb.
|
||
|
|
func ClearAllExtensions(pb Message) {
|
||
|
|
epb, err := extendable(pb)
|
||
|
|
if err != nil {
|
||
|
|
return
|
||
|
|
}
|
||
|
|
m := epb.extensionsWrite()
|
||
|
|
for k := range m {
|
||
|
|
delete(m, k)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// A global registry of extensions.
|
||
|
|
// The generated code will register the generated descriptors by calling RegisterExtension.
|
||
|
|
|
||
|
|
var extensionMaps = make(map[reflect.Type]map[int32]*ExtensionDesc)
|
||
|
|
|
||
|
|
// RegisterExtension is called from the generated code.
|
||
|
|
func RegisterExtension(desc *ExtensionDesc) {
|
||
|
|
st := reflect.TypeOf(desc.ExtendedType).Elem()
|
||
|
|
m := extensionMaps[st]
|
||
|
|
if m == nil {
|
||
|
|
m = make(map[int32]*ExtensionDesc)
|
||
|
|
extensionMaps[st] = m
|
||
|
|
}
|
||
|
|
if _, ok := m[desc.Field]; ok {
|
||
|
|
panic("proto: duplicate extension registered: " + st.String() + " " + strconv.Itoa(int(desc.Field)))
|
||
|
|
}
|
||
|
|
m[desc.Field] = desc
|
||
|
|
}
|
||
|
|
|
||
|
|
// RegisteredExtensions returns a map of the registered extensions of a
|
||
|
|
// protocol buffer struct, indexed by the extension number.
|
||
|
|
// The argument pb should be a nil pointer to the struct type.
|
||
|
|
func RegisteredExtensions(pb Message) map[int32]*ExtensionDesc {
|
||
|
|
return extensionMaps[reflect.TypeOf(pb).Elem()]
|
||
|
|
}
|
||
|
|
|
||
|
|
// extensionAsLegacyType converts an value in the storage type as the API type.
|
||
|
|
// See Extension.value.
|
||
|
|
func extensionAsLegacyType(v interface{}) interface{} {
|
||
|
|
switch rv := reflect.ValueOf(v); rv.Kind() {
|
||
|
|
case reflect.Bool, reflect.Int32, reflect.Int64, reflect.Uint32, reflect.Uint64, reflect.Float32, reflect.Float64, reflect.String:
|
||
|
|
// Represent primitive types as a pointer to the value.
|
||
|
|
rv2 := reflect.New(rv.Type())
|
||
|
|
rv2.Elem().Set(rv)
|
||
|
|
v = rv2.Interface()
|
||
|
|
case reflect.Ptr:
|
||
|
|
// Represent slice types as the value itself.
|
||
|
|
switch rv.Type().Elem().Kind() {
|
||
|
|
case reflect.Slice:
|
||
|
|
if rv.IsNil() {
|
||
|
|
v = reflect.Zero(rv.Type().Elem()).Interface()
|
||
|
|
} else {
|
||
|
|
v = rv.Elem().Interface()
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return v
|
||
|
|
}
|
||
|
|
|
||
|
|
// extensionAsStorageType converts an value in the API type as the storage type.
|
||
|
|
// See Extension.value.
|
||
|
|
func extensionAsStorageType(v interface{}) interface{} {
|
||
|
|
switch rv := reflect.ValueOf(v); rv.Kind() {
|
||
|
|
case reflect.Ptr:
|
||
|
|
// Represent slice types as the value itself.
|
||
|
|
switch rv.Type().Elem().Kind() {
|
||
|
|
case reflect.Bool, reflect.Int32, reflect.Int64, reflect.Uint32, reflect.Uint64, reflect.Float32, reflect.Float64, reflect.String:
|
||
|
|
if rv.IsNil() {
|
||
|
|
v = reflect.Zero(rv.Type().Elem()).Interface()
|
||
|
|
} else {
|
||
|
|
v = rv.Elem().Interface()
|
||
|
|
}
|
||
|
|
}
|
||
|
|
case reflect.Slice:
|
||
|
|
// Represent slice types as a pointer to the value.
|
||
|
|
if rv.Type().Elem().Kind() != reflect.Uint8 {
|
||
|
|
rv2 := reflect.New(rv.Type())
|
||
|
|
rv2.Elem().Set(rv)
|
||
|
|
v = rv2.Interface()
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return v
|
||
|
|
}
|