forked from mystiq/dex
122 lines
4.7 KiB
Go
122 lines
4.7 KiB
Go
/*
|
|
*
|
|
* Copyright 2017 gRPC authors.
|
|
*
|
|
* 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
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*
|
|
*/
|
|
|
|
// Package encoding defines the interface for the compressor and codec, and
|
|
// functions to register and retrieve compressors and codecs.
|
|
//
|
|
// This package is EXPERIMENTAL.
|
|
package encoding
|
|
|
|
import (
|
|
"io"
|
|
"strings"
|
|
)
|
|
|
|
// Identity specifies the optional encoding for uncompressed streams.
|
|
// It is intended for grpc internal use only.
|
|
const Identity = "identity"
|
|
|
|
// Compressor is used for compressing and decompressing when sending or
|
|
// receiving messages.
|
|
type Compressor interface {
|
|
// Compress writes the data written to wc to w after compressing it. If an
|
|
// error occurs while initializing the compressor, that error is returned
|
|
// instead.
|
|
Compress(w io.Writer) (io.WriteCloser, error)
|
|
// Decompress reads data from r, decompresses it, and provides the
|
|
// uncompressed data via the returned io.Reader. If an error occurs while
|
|
// initializing the decompressor, that error is returned instead.
|
|
Decompress(r io.Reader) (io.Reader, error)
|
|
// Name is the name of the compression codec and is used to set the content
|
|
// coding header. The result must be static; the result cannot change
|
|
// between calls.
|
|
Name() string
|
|
// EXPERIMENTAL: if a Compressor implements
|
|
// DecompressedSize(compressedBytes []byte) int, gRPC will call it
|
|
// to determine the size of the buffer allocated for the result of decompression.
|
|
// Return -1 to indicate unknown size.
|
|
}
|
|
|
|
var registeredCompressor = make(map[string]Compressor)
|
|
|
|
// RegisterCompressor registers the compressor with gRPC by its name. It can
|
|
// be activated when sending an RPC via grpc.UseCompressor(). It will be
|
|
// automatically accessed when receiving a message based on the content coding
|
|
// header. Servers also use it to send a response with the same encoding as
|
|
// the request.
|
|
//
|
|
// NOTE: this function must only be called during initialization time (i.e. in
|
|
// an init() function), and is not thread-safe. If multiple Compressors are
|
|
// registered with the same name, the one registered last will take effect.
|
|
func RegisterCompressor(c Compressor) {
|
|
registeredCompressor[c.Name()] = c
|
|
}
|
|
|
|
// GetCompressor returns Compressor for the given compressor name.
|
|
func GetCompressor(name string) Compressor {
|
|
return registeredCompressor[name]
|
|
}
|
|
|
|
// Codec defines the interface gRPC uses to encode and decode messages. Note
|
|
// that implementations of this interface must be thread safe; a Codec's
|
|
// methods can be called from concurrent goroutines.
|
|
type Codec interface {
|
|
// Marshal returns the wire format of v.
|
|
Marshal(v interface{}) ([]byte, error)
|
|
// Unmarshal parses the wire format into v.
|
|
Unmarshal(data []byte, v interface{}) error
|
|
// Name returns the name of the Codec implementation. The returned string
|
|
// will be used as part of content type in transmission. The result must be
|
|
// static; the result cannot change between calls.
|
|
Name() string
|
|
}
|
|
|
|
var registeredCodecs = make(map[string]Codec)
|
|
|
|
// RegisterCodec registers the provided Codec for use with all gRPC clients and
|
|
// servers.
|
|
//
|
|
// The Codec will be stored and looked up by result of its Name() method, which
|
|
// should match the content-subtype of the encoding handled by the Codec. This
|
|
// is case-insensitive, and is stored and looked up as lowercase. If the
|
|
// result of calling Name() is an empty string, RegisterCodec will panic. See
|
|
// Content-Type on
|
|
// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
|
|
// more details.
|
|
//
|
|
// NOTE: this function must only be called during initialization time (i.e. in
|
|
// an init() function), and is not thread-safe. If multiple Compressors are
|
|
// registered with the same name, the one registered last will take effect.
|
|
func RegisterCodec(codec Codec) {
|
|
if codec == nil {
|
|
panic("cannot register a nil Codec")
|
|
}
|
|
if codec.Name() == "" {
|
|
panic("cannot register Codec with empty string result for Name()")
|
|
}
|
|
contentSubtype := strings.ToLower(codec.Name())
|
|
registeredCodecs[contentSubtype] = codec
|
|
}
|
|
|
|
// GetCodec gets a registered Codec by content-subtype, or nil if no Codec is
|
|
// registered for the content-subtype.
|
|
//
|
|
// The content-subtype is expected to be lowercase.
|
|
func GetCodec(contentSubtype string) Codec {
|
|
return registeredCodecs[contentSubtype]
|
|
}
|