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56 lines
1.5 KiB
56 lines
1.5 KiB
// 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 xerrors |
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import ( |
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"runtime" |
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) |
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// A Frame contains part of a call stack. |
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type Frame struct { |
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// Make room for three PCs: the one we were asked for, what it called, |
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// and possibly a PC for skipPleaseUseCallersFrames. See: |
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// https://go.googlesource.com/go/+/032678e0fb/src/runtime/extern.go#169 |
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frames [3]uintptr |
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} |
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// Caller returns a Frame that describes a frame on the caller's stack. |
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// The argument skip is the number of frames to skip over. |
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// Caller(0) returns the frame for the caller of Caller. |
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func Caller(skip int) Frame { |
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var s Frame |
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runtime.Callers(skip+1, s.frames[:]) |
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return s |
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} |
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// location reports the file, line, and function of a frame. |
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// |
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// The returned function may be "" even if file and line are not. |
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func (f Frame) location() (function, file string, line int) { |
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frames := runtime.CallersFrames(f.frames[:]) |
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if _, ok := frames.Next(); !ok { |
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return "", "", 0 |
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} |
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fr, ok := frames.Next() |
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if !ok { |
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return "", "", 0 |
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} |
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return fr.Function, fr.File, fr.Line |
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} |
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// Format prints the stack as error detail. |
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// It should be called from an error's Format implementation |
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// after printing any other error detail. |
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func (f Frame) Format(p Printer) { |
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if p.Detail() { |
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function, file, line := f.location() |
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if function != "" { |
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p.Printf("%s\n ", function) |
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} |
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if file != "" { |
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p.Printf("%s:%d\n", file, line) |
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} |
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} |
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}
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