| 1 | // Copyright 2018 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 expect |
| 6 | |
| 7 | import ( |
| 8 | "fmt" |
| 9 | "go/ast" |
| 10 | "go/parser" |
| 11 | "go/token" |
| 12 | "path/filepath" |
| 13 | "regexp" |
| 14 | "strconv" |
| 15 | "strings" |
| 16 | "text/scanner" |
| 17 | |
| 18 | "golang.org/x/mod/modfile" |
| 19 | ) |
| 20 | |
| 21 | const commentStart = "@" |
| 22 | const commentStartLen = len(commentStart) |
| 23 | |
| 24 | // Identifier is the type for an identifier in an Note argument list. |
| 25 | type Identifier string |
| 26 | |
| 27 | // Parse collects all the notes present in a file. |
| 28 | // If content is nil, the filename specified is read and parsed, otherwise the |
| 29 | // content is used and the filename is used for positions and error messages. |
| 30 | // Each comment whose text starts with @ is parsed as a comma-separated |
| 31 | // sequence of notes. |
| 32 | // See the package documentation for details about the syntax of those |
| 33 | // notes. |
| 34 | func Parse(fset *token.FileSet, filename string, content []byte) ([]*Note, error) { |
| 35 | var src interface{} |
| 36 | if content != nil { |
| 37 | src = content |
| 38 | } |
| 39 | switch filepath.Ext(filename) { |
| 40 | case ".go": |
| 41 | // TODO: We should write this in terms of the scanner. |
| 42 | // there are ways you can break the parser such that it will not add all the |
| 43 | // comments to the ast, which may result in files where the tests are silently |
| 44 | // not run. |
| 45 | file, err := parser.ParseFile(fset, filename, src, parser.ParseComments|parser.AllErrors) |
| 46 | if file == nil { |
| 47 | return nil, err |
| 48 | } |
| 49 | return ExtractGo(fset, file) |
| 50 | case ".mod": |
| 51 | file, err := modfile.Parse(filename, content, nil) |
| 52 | if err != nil { |
| 53 | return nil, err |
| 54 | } |
| 55 | f := fset.AddFile(filename, -1, len(content)) |
| 56 | f.SetLinesForContent(content) |
| 57 | notes, err := extractMod(fset, file) |
| 58 | if err != nil { |
| 59 | return nil, err |
| 60 | } |
| 61 | // Since modfile.Parse does not return an *ast, we need to add the offset |
| 62 | // within the file's contents to the file's base relative to the fileset. |
| 63 | for _, note := range notes { |
| 64 | note.Pos += token.Pos(f.Base()) |
| 65 | } |
| 66 | return notes, nil |
| 67 | } |
| 68 | return nil, nil |
| 69 | } |
| 70 | |
| 71 | // extractMod collects all the notes present in a go.mod file. |
| 72 | // Each comment whose text starts with @ is parsed as a comma-separated |
| 73 | // sequence of notes. |
| 74 | // See the package documentation for details about the syntax of those |
| 75 | // notes. |
| 76 | // Only allow notes to appear with the following format: "//@mark()" or // @mark() |
| 77 | func extractMod(fset *token.FileSet, file *modfile.File) ([]*Note, error) { |
| 78 | var notes []*Note |
| 79 | for _, stmt := range file.Syntax.Stmt { |
| 80 | comment := stmt.Comment() |
| 81 | if comment == nil { |
| 82 | continue |
| 83 | } |
| 84 | // Handle the case for markers of `// indirect` to be on the line before |
| 85 | // the require statement. |
| 86 | // TODO(golang/go#36894): have a more intuitive approach for // indirect |
| 87 | for _, cmt := range comment.Before { |
| 88 | text, adjust := getAdjustedNote(cmt.Token) |
| 89 | if text == "" { |
| 90 | continue |
| 91 | } |
| 92 | parsed, err := parse(fset, token.Pos(int(cmt.Start.Byte)+adjust), text) |
| 93 | if err != nil { |
| 94 | return nil, err |
| 95 | } |
| 96 | notes = append(notes, parsed...) |
| 97 | } |
| 98 | // Handle the normal case for markers on the same line. |
| 99 | for _, cmt := range comment.Suffix { |
| 100 | text, adjust := getAdjustedNote(cmt.Token) |
| 101 | if text == "" { |
| 102 | continue |
| 103 | } |
| 104 | parsed, err := parse(fset, token.Pos(int(cmt.Start.Byte)+adjust), text) |
| 105 | if err != nil { |
| 106 | return nil, err |
| 107 | } |
| 108 | notes = append(notes, parsed...) |
| 109 | } |
| 110 | } |
| 111 | return notes, nil |
| 112 | } |
| 113 | |
| 114 | // ExtractGo collects all the notes present in an AST. |
| 115 | // Each comment whose text starts with @ is parsed as a comma-separated |
| 116 | // sequence of notes. |
| 117 | // See the package documentation for details about the syntax of those |
| 118 | // notes. |
| 119 | func ExtractGo(fset *token.FileSet, file *ast.File) ([]*Note, error) { |
| 120 | var notes []*Note |
| 121 | for _, g := range file.Comments { |
| 122 | for _, c := range g.List { |
| 123 | text, adjust := getAdjustedNote(c.Text) |
| 124 | if text == "" { |
| 125 | continue |
| 126 | } |
| 127 | parsed, err := parse(fset, token.Pos(int(c.Pos())+adjust), text) |
| 128 | if err != nil { |
| 129 | return nil, err |
| 130 | } |
| 131 | notes = append(notes, parsed...) |
| 132 | } |
| 133 | } |
| 134 | return notes, nil |
| 135 | } |
| 136 | |
| 137 | func getAdjustedNote(text string) (string, int) { |
| 138 | if strings.HasPrefix(text, "/*") { |
| 139 | text = strings.TrimSuffix(text, "*/") |
| 140 | } |
| 141 | text = text[2:] // remove "//" or "/*" prefix |
| 142 | |
| 143 | // Allow notes to appear within comments. |
| 144 | // For example: |
| 145 | // "// //@mark()" is valid. |
| 146 | // "// @mark()" is not valid. |
| 147 | // "// /*@mark()*/" is not valid. |
| 148 | var adjust int |
| 149 | if i := strings.Index(text, commentStart); i > 2 { |
| 150 | // Get the text before the commentStart. |
| 151 | pre := text[i-2 : i] |
| 152 | if pre != "//" { |
| 153 | return "", 0 |
| 154 | } |
| 155 | text = text[i:] |
| 156 | adjust = i |
| 157 | } |
| 158 | if !strings.HasPrefix(text, commentStart) { |
| 159 | return "", 0 |
| 160 | } |
| 161 | text = text[commentStartLen:] |
| 162 | return text, commentStartLen + adjust + 1 |
| 163 | } |
| 164 | |
| 165 | const invalidToken rune = 0 |
| 166 | |
| 167 | type tokens struct { |
| 168 | scanner scanner.Scanner |
| 169 | current rune |
| 170 | err error |
| 171 | base token.Pos |
| 172 | } |
| 173 | |
| 174 | func (t *tokens) Init(base token.Pos, text string) *tokens { |
| 175 | t.base = base |
| 176 | t.scanner.Init(strings.NewReader(text)) |
| 177 | t.scanner.Mode = scanner.GoTokens |
| 178 | t.scanner.Whitespace ^= 1 << '\n' // don't skip new lines |
| 179 | t.scanner.Error = func(s *scanner.Scanner, msg string) { |
| 180 | t.Errorf("%v", msg) |
| 181 | } |
| 182 | return t |
| 183 | } |
| 184 | |
| 185 | func (t *tokens) Consume() string { |
| 186 | t.current = invalidToken |
| 187 | return t.scanner.TokenText() |
| 188 | } |
| 189 | |
| 190 | func (t *tokens) Token() rune { |
| 191 | if t.err != nil { |
| 192 | return scanner.EOF |
| 193 | } |
| 194 | if t.current == invalidToken { |
| 195 | t.current = t.scanner.Scan() |
| 196 | } |
| 197 | return t.current |
| 198 | } |
| 199 | |
| 200 | func (t *tokens) Skip(r rune) int { |
| 201 | i := 0 |
| 202 | for t.Token() == '\n' { |
| 203 | t.Consume() |
| 204 | i++ |
| 205 | } |
| 206 | return i |
| 207 | } |
| 208 | |
| 209 | func (t *tokens) TokenString() string { |
| 210 | return scanner.TokenString(t.Token()) |
| 211 | } |
| 212 | |
| 213 | func (t *tokens) Pos() token.Pos { |
| 214 | return t.base + token.Pos(t.scanner.Position.Offset) |
| 215 | } |
| 216 | |
| 217 | func (t *tokens) Errorf(msg string, args ...interface{}) { |
| 218 | if t.err != nil { |
| 219 | return |
| 220 | } |
| 221 | t.err = fmt.Errorf(msg, args...) |
| 222 | } |
| 223 | |
| 224 | func parse(fset *token.FileSet, base token.Pos, text string) ([]*Note, error) { |
| 225 | t := new(tokens).Init(base, text) |
| 226 | notes := parseComment(t) |
| 227 | if t.err != nil { |
| 228 | return nil, fmt.Errorf("%v:%s", fset.Position(t.Pos()), t.err) |
| 229 | } |
| 230 | return notes, nil |
| 231 | } |
| 232 | |
| 233 | func parseComment(t *tokens) []*Note { |
| 234 | var notes []*Note |
| 235 | for { |
| 236 | t.Skip('\n') |
| 237 | switch t.Token() { |
| 238 | case scanner.EOF: |
| 239 | return notes |
| 240 | case scanner.Ident: |
| 241 | notes = append(notes, parseNote(t)) |
| 242 | default: |
| 243 | t.Errorf("unexpected %s parsing comment, expect identifier", t.TokenString()) |
| 244 | return nil |
| 245 | } |
| 246 | switch t.Token() { |
| 247 | case scanner.EOF: |
| 248 | return notes |
| 249 | case ',', '\n': |
| 250 | t.Consume() |
| 251 | default: |
| 252 | t.Errorf("unexpected %s parsing comment, expect separator", t.TokenString()) |
| 253 | return nil |
| 254 | } |
| 255 | } |
| 256 | } |
| 257 | |
| 258 | func parseNote(t *tokens) *Note { |
| 259 | n := &Note{ |
| 260 | Pos: t.Pos(), |
| 261 | Name: t.Consume(), |
| 262 | } |
| 263 | |
| 264 | switch t.Token() { |
| 265 | case ',', '\n', scanner.EOF: |
| 266 | // no argument list present |
| 267 | return n |
| 268 | case '(': |
| 269 | n.Args = parseArgumentList(t) |
| 270 | return n |
| 271 | default: |
| 272 | t.Errorf("unexpected %s parsing note", t.TokenString()) |
| 273 | return nil |
| 274 | } |
| 275 | } |
| 276 | |
| 277 | func parseArgumentList(t *tokens) []interface{} { |
| 278 | args := []interface{}{} // @name() is represented by a non-nil empty slice. |
| 279 | t.Consume() // '(' |
| 280 | t.Skip('\n') |
| 281 | for t.Token() != ')' { |
| 282 | args = append(args, parseArgument(t)) |
| 283 | if t.Token() != ',' { |
| 284 | break |
| 285 | } |
| 286 | t.Consume() |
| 287 | t.Skip('\n') |
| 288 | } |
| 289 | if t.Token() != ')' { |
| 290 | t.Errorf("unexpected %s parsing argument list", t.TokenString()) |
| 291 | return nil |
| 292 | } |
| 293 | t.Consume() // ')' |
| 294 | return args |
| 295 | } |
| 296 | |
| 297 | func parseArgument(t *tokens) interface{} { |
| 298 | switch t.Token() { |
| 299 | case scanner.Ident: |
| 300 | v := t.Consume() |
| 301 | switch v { |
| 302 | case "true": |
| 303 | return true |
| 304 | case "false": |
| 305 | return false |
| 306 | case "nil": |
| 307 | return nil |
| 308 | case "re": |
| 309 | if t.Token() != scanner.String && t.Token() != scanner.RawString { |
| 310 | t.Errorf("re must be followed by string, got %s", t.TokenString()) |
| 311 | return nil |
| 312 | } |
| 313 | pattern, _ := strconv.Unquote(t.Consume()) // can't fail |
| 314 | re, err := regexp.Compile(pattern) |
| 315 | if err != nil { |
| 316 | t.Errorf("invalid regular expression %s: %v", pattern, err) |
| 317 | return nil |
| 318 | } |
| 319 | return re |
| 320 | default: |
| 321 | return Identifier(v) |
| 322 | } |
| 323 | |
| 324 | case scanner.String, scanner.RawString: |
| 325 | v, _ := strconv.Unquote(t.Consume()) // can't fail |
| 326 | return v |
| 327 | |
| 328 | case scanner.Int: |
| 329 | s := t.Consume() |
| 330 | v, err := strconv.ParseInt(s, 0, 0) |
| 331 | if err != nil { |
| 332 | t.Errorf("cannot convert %v to int: %v", s, err) |
| 333 | } |
| 334 | return v |
| 335 | |
| 336 | case scanner.Float: |
| 337 | s := t.Consume() |
| 338 | v, err := strconv.ParseFloat(s, 64) |
| 339 | if err != nil { |
| 340 | t.Errorf("cannot convert %v to float: %v", s, err) |
| 341 | } |
| 342 | return v |
| 343 | |
| 344 | case scanner.Char: |
| 345 | t.Errorf("unexpected char literal %s", t.Consume()) |
| 346 | return nil |
| 347 | |
| 348 | default: |
| 349 | t.Errorf("unexpected %s parsing argument", t.TokenString()) |
| 350 | return nil |
| 351 | } |
| 352 | } |
| 353 |
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