v/vlib/context/value.v

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// This module defines the Context type, which carries deadlines, cancellation signals,
// and other request-scoped values across API boundaries and between processes.
// Based on: https://github.com/golang/go/tree/master/src/context
// Last commit: https://github.com/golang/go/commit/52bf14e0e8bdcd73f1ddfb0c4a1d0200097d3ba2
module context
import time
// A ValueContext carries a key-value pair. It implements Value for that key and
// delegates all other calls to the embedded Context.
pub struct ValueContext {
key Key
value Any
mut:
context Context
}
// with_value returns a copy of parent in which the value associated with key is
// val.
//
// Use context Values only for request-scoped data that transits processes and
// APIs, not for passing optional parameters to functions.
//
// The provided key must be comparable and should not be of type
// string or any other built-in type to avoid collisions between
// packages using context. Users of with_value should define their own
// types for keys
pub fn with_value(parent Context, key Key, value Any) Context {
return &ValueContext{
context: parent
key: key
value: value
}
}
pub fn (ctx &ValueContext) deadline() ?time.Time {
return ctx.context.deadline()
}
pub fn (ctx &ValueContext) done() chan int {
return ctx.context.done()
}
pub fn (ctx &ValueContext) err() IError {
return ctx.context.err()
}
pub fn (ctx &ValueContext) value(key Key) ?Any {
if ctx.key == key {
return ctx.value
}
return ctx.context.value(key)
}
pub fn (ctx &ValueContext) str() string {
return context_name(ctx.context) + '.with_value'
}