44 lines
1.0 KiB
Go
44 lines
1.0 KiB
Go
// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package fmt
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import "errors"
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// Errorf formats according to a format specifier and returns the string as a
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// value that satisfies error.
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//
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// If the format specifier includes a %w verb with an error operand,
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// the returned error will implement an Unwrap method returning the operand. It is
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// invalid to include more than one %w verb or to supply it with an operand
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// that does not implement the error interface. The %w verb is otherwise
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// a synonym for %v.
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func Errorf(format string, a ...interface{}) error {
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p := newPrinter()
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p.wrapErrs = true
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p.doPrintf(format, a)
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s := string(p.buf)
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var err error
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if p.wrappedErr == nil {
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err = errors.New(s)
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} else {
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err = &wrapError{s, p.wrappedErr}
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}
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p.free()
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return err
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}
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type wrapError struct {
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msg string
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err error
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}
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func (e *wrapError) Error() string {
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return e.msg
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}
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func (e *wrapError) Unwrap() error {
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return e.err
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}
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