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 *
 * Copyright 2016, Google Inc.
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 * modification, are permitted provided that the following conditions are
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 *
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 * notice, this list of conditions and the following disclaimer.
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 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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 */

package grpc

import (
	"golang.org/x/net/context"
)

// UnaryInvoker is called by UnaryClientInterceptor to complete RPCs.
type UnaryInvoker func(ctx context.Context, method string, req, reply interface{}, cc *ClientConn, opts ...CallOption) error

// UnaryClientInterceptor intercepts the execution of a unary RPC on the client. invoker is the handler to complete the RPC
// and it is the responsibility of the interceptor to call it.
// This is the EXPERIMENTAL API.
type UnaryClientInterceptor func(ctx context.Context, method string, req, reply interface{}, cc *ClientConn, invoker UnaryInvoker, opts ...CallOption) error

// Streamer is called by StreamClientInterceptor to create a ClientStream.
type Streamer func(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (ClientStream, error)

// StreamClientInterceptor intercepts the creation of ClientStream. It may return a custom ClientStream to intercept all I/O
// operations. streamer is the handlder to create a ClientStream and it is the responsibility of the interceptor to call it.
// This is the EXPERIMENTAL API.
type StreamClientInterceptor func(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, streamer Streamer, opts ...CallOption) (ClientStream, error)

// UnaryServerInfo consists of various information about a unary RPC on
// server side. All per-rpc information may be mutated by the interceptor.
type UnaryServerInfo struct {
	// Server is the service implementation the user provides. This is read-only.
	Server interface{}
	// FullMethod is the full RPC method string, i.e., /package.service/method.
	FullMethod string
}

// UnaryHandler defines the handler invoked by UnaryServerInterceptor to complete the normal
// execution of a unary RPC.
type UnaryHandler func(ctx context.Context, req interface{}) (interface{}, error)

// UnaryServerInterceptor provides a hook to intercept the execution of a unary RPC on the server. info
// contains all the information of this RPC the interceptor can operate on. And handler is the wrapper
// of the service method implementation. It is the responsibility of the interceptor to invoke handler
// to complete the RPC.
type UnaryServerInterceptor func(ctx context.Context, req interface{}, info *UnaryServerInfo, handler UnaryHandler) (resp interface{}, err error)

// StreamServerInfo consists of various information about a streaming RPC on
// server side. All per-rpc information may be mutated by the interceptor.
type StreamServerInfo struct {
	// FullMethod is the full RPC method string, i.e., /package.service/method.
	FullMethod string
	// IsClientStream indicates whether the RPC is a client streaming RPC.
	IsClientStream bool
	// IsServerStream indicates whether the RPC is a server streaming RPC.
	IsServerStream bool
}

// StreamServerInterceptor provides a hook to intercept the execution of a streaming RPC on the server.
// info contains all the information of this RPC the interceptor can operate on. And handler is the
// service method implementation. It is the responsibility of the interceptor to invoke handler to
// complete the RPC.
type StreamServerInterceptor func(srv interface{}, ss ServerStream, info *StreamServerInfo, handler StreamHandler) error
