status-go/vendor/go.uber.org/fx/lifecycle.go

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// Copyright (c) 2022 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package fx
import (
"context"
"go.uber.org/fx/internal/lifecycle"
)
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// A HookFunc is a function that can be used as a [Hook].
type HookFunc interface {
~func() | ~func() error | ~func(context.Context) | ~func(context.Context) error
}
// Lifecycle allows constructors to register callbacks that are executed on
// application start and stop. See the documentation for App for details on Fx
// applications' initialization, startup, and shutdown logic.
type Lifecycle interface {
Append(Hook)
}
// A Hook is a pair of start and stop callbacks, either of which can be nil.
// If a Hook's OnStart callback isn't executed (because a previous OnStart
// failure short-circuited application startup), its OnStop callback won't be
// executed.
type Hook struct {
OnStart func(context.Context) error
OnStop func(context.Context) error
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onStartName string
onStopName string
}
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// StartHook returns a new Hook with start as its [Hook.OnStart] function,
// wrapping its signature as needed. For example, given the following function:
//
// func myhook() {
// fmt.Println("hook called")
// }
//
// then calling:
//
// lifecycle.Append(StartHook(myfunc))
//
// is functionally equivalent to calling:
//
// lifecycle.Append(fx.Hook{
// OnStart: func(context.Context) error {
// myfunc()
// return nil
// },
// })
//
// The same is true for all functions that satisfy the HookFunc constraint.
// Note that any context.Context parameter or error return will be propagated
// as expected. If propagation is not intended, users should instead provide a
// closure that discards the undesired value(s), or construct a Hook directly.
func StartHook[T HookFunc](start T) Hook {
onstart, startname := lifecycle.Wrap(start)
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return Hook{
OnStart: onstart,
onStartName: startname,
}
}
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// StopHook returns a new Hook with stop as its [Hook.OnStop] function,
// wrapping its signature as needed. For example, given the following function:
//
// func myhook() {
// fmt.Println("hook called")
// }
//
// then calling:
//
// lifecycle.Append(StopHook(myfunc))
//
// is functionally equivalent to calling:
//
// lifecycle.Append(fx.Hook{
// OnStop: func(context.Context) error {
// myfunc()
// return nil
// },
// })
//
// The same is true for all functions that satisfy the HookFunc constraint.
// Note that any context.Context parameter or error return will be propagated
// as expected. If propagation is not intended, users should instead provide a
// closure that discards the undesired value(s), or construct a Hook directly.
func StopHook[T HookFunc](stop T) Hook {
onstop, stopname := lifecycle.Wrap(stop)
return Hook{
OnStop: onstop,
onStopName: stopname,
}
}
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// StartStopHook returns a new Hook with start as its [Hook.OnStart] function
// and stop as its [Hook.OnStop] function, independently wrapping the signature
// of each as needed.
func StartStopHook[T1 HookFunc, T2 HookFunc](start T1, stop T2) Hook {
var (
onstart, startname = lifecycle.Wrap(start)
onstop, stopname = lifecycle.Wrap(stop)
)
return Hook{
OnStart: onstart,
OnStop: onstop,
onStartName: startname,
onStopName: stopname,
}
}
type lifecycleWrapper struct {
*lifecycle.Lifecycle
}
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func (l *lifecycleWrapper) Append(h Hook) {
l.Lifecycle.Append(lifecycle.Hook{
OnStart: h.OnStart,
OnStop: h.OnStop,
OnStartName: h.onStartName,
OnStopName: h.onStopName,
})
}