github.com/hxx258456/ccgo@v0.0.5-0.20230213014102-48b35f46f66f/grpc/internal/metadata/metadata.go (about)

     1  /*
     2   *
     3   * Copyright 2020 gRPC authors.
     4   *
     5   * Licensed under the Apache License, Version 2.0 (the "License");
     6   * you may not use this file except in compliance with the License.
     7   * You may obtain a copy of the License at
     8   *
     9   *     http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   *
    17   */
    18  
    19  // Package metadata contains functions to set and get metadata from addresses.
    20  //
    21  // This package is experimental.
    22  package metadata
    23  
    24  import (
    25  	"github.com/hxx258456/ccgo/grpc/metadata"
    26  	"github.com/hxx258456/ccgo/grpc/resolver"
    27  )
    28  
    29  type mdKeyType string
    30  
    31  const mdKey = mdKeyType("grpc.internal.address.metadata")
    32  
    33  type mdValue metadata.MD
    34  
    35  func (m mdValue) Equal(o interface{}) bool {
    36  	om, ok := o.(mdValue)
    37  	if !ok {
    38  		return false
    39  	}
    40  	if len(m) != len(om) {
    41  		return false
    42  	}
    43  	for k, v := range m {
    44  		ov := om[k]
    45  		if len(ov) != len(v) {
    46  			return false
    47  		}
    48  		for i, ve := range v {
    49  			if ov[i] != ve {
    50  				return false
    51  			}
    52  		}
    53  	}
    54  	return true
    55  }
    56  
    57  // Get returns the metadata of addr.
    58  func Get(addr resolver.Address) metadata.MD {
    59  	attrs := addr.Attributes
    60  	if attrs == nil {
    61  		return nil
    62  	}
    63  	md, _ := attrs.Value(mdKey).(mdValue)
    64  	return metadata.MD(md)
    65  }
    66  
    67  // Set sets (overrides) the metadata in addr.
    68  //
    69  // When a SubConn is created with this address, the RPCs sent on it will all
    70  // have this metadata.
    71  func Set(addr resolver.Address, md metadata.MD) resolver.Address {
    72  	addr.Attributes = addr.Attributes.WithValue(mdKey, mdValue(md))
    73  	return addr
    74  }