robocar-steering-tflite-edg.../vendor/go.opentelemetry.io/otel/trace/context.go

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// Copyright The OpenTelemetry 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 trace // import "go.opentelemetry.io/otel/trace"
import "context"
type traceContextKeyType int
const currentSpanKey traceContextKeyType = iota
// ContextWithSpan returns a copy of parent with span set as the current Span.
func ContextWithSpan(parent context.Context, span Span) context.Context {
return context.WithValue(parent, currentSpanKey, span)
}
// ContextWithSpanContext returns a copy of parent with sc as the current
// Span. The Span implementation that wraps sc is non-recording and performs
// no operations other than to return sc as the SpanContext from the
// SpanContext method.
func ContextWithSpanContext(parent context.Context, sc SpanContext) context.Context {
return ContextWithSpan(parent, nonRecordingSpan{sc: sc})
}
// ContextWithRemoteSpanContext returns a copy of parent with rsc set explicly
// as a remote SpanContext and as the current Span. The Span implementation
// that wraps rsc is non-recording and performs no operations other than to
// return rsc as the SpanContext from the SpanContext method.
func ContextWithRemoteSpanContext(parent context.Context, rsc SpanContext) context.Context {
return ContextWithSpanContext(parent, rsc.WithRemote(true))
}
// SpanFromContext returns the current Span from ctx.
//
// If no Span is currently set in ctx an implementation of a Span that
// performs no operations is returned.
func SpanFromContext(ctx context.Context) Span {
if ctx == nil {
return noopSpan{}
}
if span, ok := ctx.Value(currentSpanKey).(Span); ok {
return span
}
return noopSpan{}
}
// SpanContextFromContext returns the current Span's SpanContext.
func SpanContextFromContext(ctx context.Context) SpanContext {
return SpanFromContext(ctx).SpanContext()
}