github.com/v2fly/v2ray-core/v4@v4.45.2/context.go (about)

     1  //go:build !confonly
     2  // +build !confonly
     3  
     4  package core
     5  
     6  import (
     7  	"context"
     8  )
     9  
    10  // V2rayKey is the key type of Instance in Context, exported for test.
    11  type v2rayKeyType int
    12  
    13  const v2rayKey v2rayKeyType = 1
    14  
    15  // FromContext returns an Instance from the given context, or nil if the context doesn't contain one.
    16  func FromContext(ctx context.Context) *Instance {
    17  	if s, ok := ctx.Value(v2rayKey).(*Instance); ok {
    18  		return s
    19  	}
    20  	return nil
    21  }
    22  
    23  // MustFromContext returns an Instance from the given context, or panics if not present.
    24  func MustFromContext(ctx context.Context) *Instance {
    25  	v := FromContext(ctx)
    26  	if v == nil {
    27  		panic("V is not in context.")
    28  	}
    29  	return v
    30  }
    31  
    32  /* toContext returns ctx from the given context, or creates an Instance if the context doesn't find that.
    33  
    34  It is unsupported to use this function to create a context that is suitable to invoke V2Ray's internal component
    35  in third party code, you shouldn't use //go:linkname to alias of this function into your own package and
    36  use this function in your third party code.
    37  
    38  For third party code, usage enabled by creating a context to interact with V2Ray's internal component is unsupported,
    39  and may break at any time.
    40  
    41  */
    42  func toContext(ctx context.Context, v *Instance) context.Context {
    43  	if FromContext(ctx) != v {
    44  		ctx = context.WithValue(ctx, v2rayKey, v)
    45  	}
    46  	return ctx
    47  }
    48  
    49  /*ToBackgroundDetachedContext create a detached context from another context
    50  Internal API
    51  */
    52  func ToBackgroundDetachedContext(ctx context.Context) context.Context {
    53  	return &temporaryValueDelegationFix{context.Background(), ctx}
    54  }
    55  
    56  type temporaryValueDelegationFix struct {
    57  	context.Context
    58  	value context.Context
    59  }
    60  
    61  func (t *temporaryValueDelegationFix) Value(key interface{}) interface{} {
    62  	return t.value.Value(key)
    63  }