84 lines
2.6 KiB
Go
84 lines
2.6 KiB
Go
// Copyright 2019 The Gitea Authors. All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package log
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import (
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"bytes"
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"fmt"
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"io/ioutil"
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"runtime"
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)
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var (
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unknown = []byte("???")
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)
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// Stack will skip back the provided number of frames and return a stack trace with source code.
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// Although we could just use debug.Stack(), this routine will return the source code and
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// skip back the provided number of frames - i.e. allowing us to ignore preceding function calls.
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// A skip of 0 returns the stack trace for the calling function, not including this call.
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// If the problem is a lack of memory of course all this is not going to work...
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func Stack(skip int) string {
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buf := new(bytes.Buffer)
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// Store the last file we opened as its probable that the preceding stack frame
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// will be in the same file
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var lines [][]byte
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var lastFilename string
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for i := skip + 1; ; i++ { // Skip over frames
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programCounter, filename, lineNumber, ok := runtime.Caller(i)
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// If we can't retrieve the information break - basically we're into go internals at this point.
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if !ok {
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break
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}
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// Print equivalent of debug.Stack()
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fmt.Fprintf(buf, "%s:%d (0x%x)\n", filename, lineNumber, programCounter)
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// Now try to print the offending line
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if filename != lastFilename {
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data, err := ioutil.ReadFile(filename)
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if err != nil {
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// can't read this sourcefile
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// likely we don't have the sourcecode available
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continue
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}
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lines = bytes.Split(data, []byte{'\n'})
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lastFilename = filename
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}
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fmt.Fprintf(buf, "\t%s: %s\n", functionName(programCounter), source(lines, lineNumber))
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}
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return buf.String()
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}
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// functionName converts the provided programCounter into a function name
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func functionName(programCounter uintptr) []byte {
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function := runtime.FuncForPC(programCounter)
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if function == nil {
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return unknown
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}
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name := []byte(function.Name())
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// Because we provide the filename we can drop the preceding package name.
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if lastslash := bytes.LastIndex(name, []byte("/")); lastslash >= 0 {
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name = name[lastslash+1:]
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}
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// And the current package name.
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if period := bytes.Index(name, []byte(".")); period >= 0 {
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name = name[period+1:]
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}
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// And we should just replace the interpunct with a dot
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name = bytes.ReplaceAll(name, []byte("·"), []byte("."))
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return name
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}
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// source returns a space-trimmed slice of the n'th line.
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func source(lines [][]byte, n int) []byte {
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n-- // in stack trace, lines are 1-indexed but our array is 0-indexed
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if n < 0 || n >= len(lines) {
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return unknown
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}
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return bytes.TrimSpace(lines[n])
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}
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