103 lines
2.9 KiB
Go
103 lines
2.9 KiB
Go
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package panics
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import (
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"fmt"
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"runtime"
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"runtime/debug"
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"sync/atomic"
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)
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// Catcher is used to catch panics. You can execute a function with Try,
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// which will catch any spawned panic. Try can be called any number of times,
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// from any number of goroutines. Once all calls to Try have completed, you can
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// get the value of the first panic (if any) with Recovered(), or you can just
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// propagate the panic (re-panic) with Repanic().
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type Catcher struct {
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recovered atomic.Pointer[Recovered]
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}
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// Try executes f, catching any panic it might spawn. It is safe
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// to call from multiple goroutines simultaneously.
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func (p *Catcher) Try(f func()) {
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defer p.tryRecover()
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f()
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}
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func (p *Catcher) tryRecover() {
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if val := recover(); val != nil {
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rp := NewRecovered(1, val)
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p.recovered.CompareAndSwap(nil, &rp)
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}
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}
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// Repanic panics if any calls to Try caught a panic. It will panic with the
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// value of the first panic caught, wrapped in a panics.Recovered with caller
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// information.
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func (p *Catcher) Repanic() {
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if val := p.Recovered(); val != nil {
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panic(val)
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}
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}
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// Recovered returns the value of the first panic caught by Try, or nil if
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// no calls to Try panicked.
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func (p *Catcher) Recovered() *Recovered {
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return p.recovered.Load()
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}
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// NewRecovered creates a panics.Recovered from a panic value and a collected
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// stacktrace. The skip parameter allows the caller to skip stack frames when
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// collecting the stacktrace. Calling with a skip of 0 means include the call to
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// NewRecovered in the stacktrace.
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func NewRecovered(skip int, value any) Recovered {
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// 64 frames should be plenty
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var callers [64]uintptr
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n := runtime.Callers(skip+1, callers[:])
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return Recovered{
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Value: value,
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Callers: callers[:n],
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Stack: debug.Stack(),
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}
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}
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// Recovered is a panic that was caught with recover().
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type Recovered struct {
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// The original value of the panic.
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Value any
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// The caller list as returned by runtime.Callers when the panic was
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// recovered. Can be used to produce a more detailed stack information with
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// runtime.CallersFrames.
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Callers []uintptr
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// The formatted stacktrace from the goroutine where the panic was recovered.
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// Easier to use than Callers.
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Stack []byte
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}
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// String renders a human-readable formatting of the panic.
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func (p *Recovered) String() string {
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return fmt.Sprintf("panic: %v\nstacktrace:\n%s\n", p.Value, p.Stack)
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}
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// AsError casts the panic into an error implementation. The implementation
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// is unwrappable with the cause of the panic, if the panic was provided one.
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func (p *Recovered) AsError() error {
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if p == nil {
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return nil
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}
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return &ErrRecovered{*p}
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}
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// ErrRecovered wraps a panics.Recovered in an error implementation.
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type ErrRecovered struct{ Recovered }
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var _ error = (*ErrRecovered)(nil)
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func (p *ErrRecovered) Error() string { return p.String() }
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func (p *ErrRecovered) Unwrap() error {
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if err, ok := p.Value.(error); ok {
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return err
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}
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return nil
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}
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