82 lines
3.1 KiB
Go
82 lines
3.1 KiB
Go
/*
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*
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* Copyright 2024 gRPC authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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package encoding
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import (
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"strings"
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"google.golang.org/grpc/mem"
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)
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// CodecV2 defines the interface gRPC uses to encode and decode messages. Note
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// that implementations of this interface must be thread safe; a CodecV2's
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// methods can be called from concurrent goroutines.
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type CodecV2 interface {
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// Marshal returns the wire format of v. The buffers in the returned
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// [mem.BufferSlice] must have at least one reference each, which will be freed
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// by gRPC when they are no longer needed.
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Marshal(v any) (out mem.BufferSlice, err error)
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// Unmarshal parses the wire format into v. Note that data will be freed as soon
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// as this function returns. If the codec wishes to guarantee access to the data
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// after this function, it must take its own reference that it frees when it is
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// no longer needed.
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Unmarshal(data mem.BufferSlice, v any) error
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// Name returns the name of the Codec implementation. The returned string
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// will be used as part of content type in transmission. The result must be
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// static; the result cannot change between calls.
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Name() string
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}
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// RegisterCodecV2 registers the provided CodecV2 for use with all gRPC clients and
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// servers.
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//
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// The CodecV2 will be stored and looked up by result of its Name() method, which
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// should match the content-subtype of the encoding handled by the CodecV2. This
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// is case-insensitive, and is stored and looked up as lowercase. If the
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// result of calling Name() is an empty string, RegisterCodecV2 will panic. See
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// Content-Type on
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// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
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// more details.
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//
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// If both a Codec and CodecV2 are registered with the same name, the CodecV2
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// will be used.
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//
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// NOTE: this function must only be called during initialization time (i.e. in
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// an init() function), and is not thread-safe. If multiple Codecs are
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// registered with the same name, the one registered last will take effect.
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func RegisterCodecV2(codec CodecV2) {
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if codec == nil {
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panic("cannot register a nil CodecV2")
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}
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if codec.Name() == "" {
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panic("cannot register CodecV2 with empty string result for Name()")
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}
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contentSubtype := strings.ToLower(codec.Name())
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registeredCodecs[contentSubtype] = codec
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}
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// GetCodecV2 gets a registered CodecV2 by content-subtype, or nil if no CodecV2 is
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// registered for the content-subtype.
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//
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// The content-subtype is expected to be lowercase.
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func GetCodecV2(contentSubtype string) CodecV2 {
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c, _ := registeredCodecs[contentSubtype].(CodecV2)
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return c
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}
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