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context.go
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context.go
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// Copyright 2015 The Cockroach 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. See the AUTHORS file
// for names of contributors.
//
// Author: Tobias Schottdorf
package log
import "golang.org/x/net/context"
// Add takes a context and an additional even number of arguments,
// interpreted as key-value pairs. These are added on top of the
// supplied context and the resulting context returned.
func Add(ctx context.Context, kvs ...interface{}) context.Context {
l := len(kvs)
if l%2 != 0 {
panic("Add called with odd number of arguments")
}
for i := 1; i < l; i += 2 {
ctx = context.WithValue(ctx, kvs[i-1], kvs[i])
}
return ctx
}
type kvSlice []interface{}
func contextKV(ctx context.Context) kvSlice {
// TODO(tschottdorf): Could put an LRU cache here if parsing the contexts
// turns out to be a lot of work - there will be a few static ones, and
// then one per client.
if ctx == nil {
return nil
}
var r []interface{}
for i := Field(0); i < maxField; i++ {
if v := ctx.Value(i); v != nil {
r = append(r, i, v)
}
}
return r
}