Xray-core/core/context.go

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2020-11-25 13:01:53 +02:00
package core
import (
"context"
)
// XrayKey is the key type of Instance in Context, exported for test.
type XrayKey int
const xrayKey XrayKey = 1
// FromContext returns an Instance from the given context, or nil if the context doesn't contain one.
func FromContext(ctx context.Context) *Instance {
if s, ok := ctx.Value(xrayKey).(*Instance); ok {
return s
}
return nil
}
// MustFromContext returns an Instance from the given context, or panics if not present.
func MustFromContext(ctx context.Context) *Instance {
x := FromContext(ctx)
if x == nil {
panic("X is not in context.")
}
return x
}
/* toContext returns ctx from the given context, or creates an Instance if the context doesn't find that.
It is unsupported to use this function to create a context that is suitable to invoke Xray's internal component
in third party code, you shouldn't use //go:linkname to alias of this function into your own package and
use this function in your third party code.
For third party code, usage enabled by creating a context to interact with Xray's internal component is unsupported,
and may break at any time.
*/
func toContext(ctx context.Context, v *Instance) context.Context {
if FromContext(ctx) != v {
ctx = context.WithValue(ctx, xrayKey, v)
}
return ctx
}
/*ToBackgroundDetachedContext create a detached context from another context
Internal API
*/
func ToBackgroundDetachedContext(ctx context.Context) context.Context {
instance := MustFromContext(ctx)
return toContext(context.Background(), instance)
}