| 1 | // Copyright 2020 The Go Authors. All rights reserved. |
|---|---|
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | package stack |
| 6 | |
| 7 | import ( |
| 8 | "bufio" |
| 9 | "errors" |
| 10 | "io" |
| 11 | "regexp" |
| 12 | "strconv" |
| 13 | ) |
| 14 | |
| 15 | var ( |
| 16 | reBlank = regexp.MustCompile(`^\s*$`) |
| 17 | reGoroutine = regexp.MustCompile(`^\s*goroutine (\d+) \[([^\]]*)\]:\s*$`) |
| 18 | reCall = regexp.MustCompile(`^\s*` + |
| 19 | `(created by )?` + //marker |
| 20 | `(([\w/.]+/)?[\w]+)\.` + //package |
| 21 | `(\(([^:.)]*)\)\.)?` + //optional type |
| 22 | `([\w\.]+)` + //function |
| 23 | `(\(.*\))?` + // args |
| 24 | `\s*$`) |
| 25 | rePos = regexp.MustCompile(`^\s*(.*):(\d+)( .*)?$`) |
| 26 | |
| 27 | errBreakParse = errors.New("break parse") |
| 28 | ) |
| 29 | |
| 30 | // Scanner splits an input stream into lines in a way that is consumable by |
| 31 | // the parser. |
| 32 | type Scanner struct { |
| 33 | lines *bufio.Scanner |
| 34 | done bool |
| 35 | } |
| 36 | |
| 37 | // NewScanner creates a scanner on top of a reader. |
| 38 | func NewScanner(r io.Reader) *Scanner { |
| 39 | s := &Scanner{ |
| 40 | lines: bufio.NewScanner(r), |
| 41 | } |
| 42 | s.Skip() // prefill |
| 43 | return s |
| 44 | } |
| 45 | |
| 46 | // Peek returns the next line without consuming it. |
| 47 | func (s *Scanner) Peek() string { |
| 48 | if s.done { |
| 49 | return "" |
| 50 | } |
| 51 | return s.lines.Text() |
| 52 | } |
| 53 | |
| 54 | // Skip consumes the next line without looking at it. |
| 55 | // Normally used after it has already been looked at using Peek. |
| 56 | func (s *Scanner) Skip() { |
| 57 | if !s.lines.Scan() { |
| 58 | s.done = true |
| 59 | } |
| 60 | } |
| 61 | |
| 62 | // Next consumes and returns the next line. |
| 63 | func (s *Scanner) Next() string { |
| 64 | line := s.Peek() |
| 65 | s.Skip() |
| 66 | return line |
| 67 | } |
| 68 | |
| 69 | // Done returns true if the scanner has reached the end of the underlying |
| 70 | // stream. |
| 71 | func (s *Scanner) Done() bool { |
| 72 | return s.done |
| 73 | } |
| 74 | |
| 75 | // Err returns true if the scanner has reached the end of the underlying |
| 76 | // stream. |
| 77 | func (s *Scanner) Err() error { |
| 78 | return s.lines.Err() |
| 79 | } |
| 80 | |
| 81 | // Match returns the submatchs of the regular expression against the next line. |
| 82 | // If it matched the line is also consumed. |
| 83 | func (s *Scanner) Match(re *regexp.Regexp) []string { |
| 84 | if s.done { |
| 85 | return nil |
| 86 | } |
| 87 | match := re.FindStringSubmatch(s.Peek()) |
| 88 | if match != nil { |
| 89 | s.Skip() |
| 90 | } |
| 91 | return match |
| 92 | } |
| 93 | |
| 94 | // SkipBlank skips any number of pure whitespace lines. |
| 95 | func (s *Scanner) SkipBlank() { |
| 96 | for !s.done { |
| 97 | line := s.Peek() |
| 98 | if len(line) != 0 && !reBlank.MatchString(line) { |
| 99 | return |
| 100 | } |
| 101 | s.Skip() |
| 102 | } |
| 103 | } |
| 104 | |
| 105 | // Parse the current contiguous block of goroutine stack traces until the |
| 106 | // scanned content no longer matches. |
| 107 | func Parse(scanner *Scanner) (Dump, error) { |
| 108 | dump := Dump{} |
| 109 | for { |
| 110 | gr, ok := parseGoroutine(scanner) |
| 111 | if !ok { |
| 112 | return dump, nil |
| 113 | } |
| 114 | dump = append(dump, gr) |
| 115 | } |
| 116 | } |
| 117 | |
| 118 | func parseGoroutine(scanner *Scanner) (Goroutine, bool) { |
| 119 | match := scanner.Match(reGoroutine) |
| 120 | if match == nil { |
| 121 | return Goroutine{}, false |
| 122 | } |
| 123 | id, _ := strconv.ParseInt(match[1], 0, 32) |
| 124 | gr := Goroutine{ |
| 125 | ID: int(id), |
| 126 | State: match[2], |
| 127 | } |
| 128 | for { |
| 129 | frame, ok := parseFrame(scanner) |
| 130 | if !ok { |
| 131 | scanner.SkipBlank() |
| 132 | return gr, true |
| 133 | } |
| 134 | if frame.Position.Filename != "" { |
| 135 | gr.Stack = append(gr.Stack, frame) |
| 136 | } |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | func parseFrame(scanner *Scanner) (Frame, bool) { |
| 141 | fun, ok := parseFunction(scanner) |
| 142 | if !ok { |
| 143 | return Frame{}, false |
| 144 | } |
| 145 | frame := Frame{ |
| 146 | Function: fun, |
| 147 | } |
| 148 | frame.Position, ok = parsePosition(scanner) |
| 149 | // if ok is false, then this is a broken state. |
| 150 | // we got the func but not the file that must follow |
| 151 | // the consumed line can be recovered from the frame |
| 152 | //TODO: push back the fun raw |
| 153 | return frame, ok |
| 154 | } |
| 155 | |
| 156 | func parseFunction(scanner *Scanner) (Function, bool) { |
| 157 | match := scanner.Match(reCall) |
| 158 | if match == nil { |
| 159 | return Function{}, false |
| 160 | } |
| 161 | return Function{ |
| 162 | Package: match[2], |
| 163 | Type: match[5], |
| 164 | Name: match[6], |
| 165 | }, true |
| 166 | } |
| 167 | |
| 168 | func parsePosition(scanner *Scanner) (Position, bool) { |
| 169 | match := scanner.Match(rePos) |
| 170 | if match == nil { |
| 171 | return Position{}, false |
| 172 | } |
| 173 | line, _ := strconv.ParseInt(match[2], 0, 32) |
| 174 | return Position{Filename: match[1], Line: int(line)}, true |
| 175 | } |
| 176 |
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