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-rw-r--r--modules/log/stack.go80
1 files changed, 80 insertions, 0 deletions
diff --git a/modules/log/stack.go b/modules/log/stack.go
new file mode 100644
index 0000000..9b22e92
--- /dev/null
+++ b/modules/log/stack.go
@@ -0,0 +1,80 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+ "bytes"
+ "fmt"
+ "os"
+ "runtime"
+)
+
+var unknown = []byte("???")
+
+// Stack will skip back the provided number of frames and return a stack trace with source code.
+// Although we could just use debug.Stack(), this routine will return the source code and
+// skip back the provided number of frames - i.e. allowing us to ignore preceding function calls.
+// A skip of 0 returns the stack trace for the calling function, not including this call.
+// If the problem is a lack of memory of course all this is not going to work...
+func Stack(skip int) string {
+ buf := new(bytes.Buffer)
+
+ // Store the last file we opened as its probable that the preceding stack frame
+ // will be in the same file
+ var lines [][]byte
+ var lastFilename string
+ for i := skip + 1; ; i++ { // Skip over frames
+ programCounter, filename, lineNumber, ok := runtime.Caller(i)
+ // If we can't retrieve the information break - basically we're into go internals at this point.
+ if !ok {
+ break
+ }
+
+ // Print equivalent of debug.Stack()
+ _, _ = fmt.Fprintf(buf, "%s:%d (0x%x)\n", filename, lineNumber, programCounter)
+ // Now try to print the offending line
+ if filename != lastFilename {
+ data, err := os.ReadFile(filename)
+ if err != nil {
+ // can't read this source file
+ // likely we don't have the sourcecode available
+ continue
+ }
+ lines = bytes.Split(data, []byte{'\n'})
+ lastFilename = filename
+ }
+ _, _ = fmt.Fprintf(buf, "\t%s: %s\n", functionName(programCounter), source(lines, lineNumber))
+ }
+ return buf.String()
+}
+
+// functionName converts the provided programCounter into a function name
+func functionName(programCounter uintptr) []byte {
+ function := runtime.FuncForPC(programCounter)
+ if function == nil {
+ return unknown
+ }
+ name := []byte(function.Name())
+
+ // Because we provide the filename we can drop the preceding package name.
+ if lastslash := bytes.LastIndex(name, []byte("/")); lastslash >= 0 {
+ name = name[lastslash+1:]
+ }
+ // And the current package name.
+ if period := bytes.Index(name, []byte(".")); period >= 0 {
+ name = name[period+1:]
+ }
+ // And we should just replace the interpunct with a dot
+ name = bytes.ReplaceAll(name, []byte("ยท"), []byte("."))
+ return name
+}
+
+// source returns a space-trimmed slice of the n'th line.
+func source(lines [][]byte, n int) []byte {
+ n-- // in stack trace, lines are 1-indexed but our array is 0-indexed
+ if n < 0 || n >= len(lines) {
+ return unknown
+ }
+ return bytes.TrimSpace(lines[n])
+}