| 1 | // Copyright 2013 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 main |
| 6 | |
| 7 | import ( |
| 8 | "bytes" |
| 9 | "fmt" |
| 10 | "go/ast" |
| 11 | "go/constant" |
| 12 | "go/token" |
| 13 | "go/types" |
| 14 | "os" |
| 15 | "strings" |
| 16 | "unicode/utf8" |
| 17 | |
| 18 | "golang.org/x/tools/cmd/guru/serial" |
| 19 | "golang.org/x/tools/go/ast/astutil" |
| 20 | "golang.org/x/tools/go/loader" |
| 21 | "golang.org/x/tools/go/types/typeutil" |
| 22 | ) |
| 23 | |
| 24 | // describe describes the syntax node denoted by the query position, |
| 25 | // including: |
| 26 | // - its syntactic category |
| 27 | // - the definition of its referent (for identifiers) [now redundant] |
| 28 | // - its type, fields, and methods (for an expression or type expression) |
| 29 | func describe(q *Query) error { |
| 30 | lconf := loader.Config{Build: q.Build} |
| 31 | allowErrors(&lconf) |
| 32 | |
| 33 | if _, err := importQueryPackage(q.Pos, &lconf); err != nil { |
| 34 | return err |
| 35 | } |
| 36 | |
| 37 | // Load/parse/type-check the program. |
| 38 | lprog, err := lconf.Load() |
| 39 | if err != nil { |
| 40 | return err |
| 41 | } |
| 42 | |
| 43 | qpos, err := parseQueryPos(lprog, q.Pos, true) // (need exact pos) |
| 44 | if err != nil { |
| 45 | return err |
| 46 | } |
| 47 | |
| 48 | if false { // debugging |
| 49 | fprintf(os.Stderr, lprog.Fset, qpos.path[0], "you selected: %s %s", |
| 50 | astutil.NodeDescription(qpos.path[0]), pathToString(qpos.path)) |
| 51 | } |
| 52 | |
| 53 | var qr QueryResult |
| 54 | path, action := findInterestingNode(qpos.info, qpos.path) |
| 55 | switch action { |
| 56 | case actionExpr: |
| 57 | qr, err = describeValue(qpos, path) |
| 58 | |
| 59 | case actionType: |
| 60 | qr, err = describeType(qpos, path) |
| 61 | |
| 62 | case actionPackage: |
| 63 | qr, err = describePackage(qpos, path) |
| 64 | |
| 65 | case actionStmt: |
| 66 | qr, err = describeStmt(qpos, path) |
| 67 | |
| 68 | case actionUnknown: |
| 69 | qr = &describeUnknownResult{path[0]} |
| 70 | |
| 71 | default: |
| 72 | panic(action) // unreachable |
| 73 | } |
| 74 | if err != nil { |
| 75 | return err |
| 76 | } |
| 77 | q.Output(lprog.Fset, qr) |
| 78 | return nil |
| 79 | } |
| 80 | |
| 81 | type describeUnknownResult struct { |
| 82 | node ast.Node |
| 83 | } |
| 84 | |
| 85 | func (r *describeUnknownResult) PrintPlain(printf printfFunc) { |
| 86 | // Nothing much to say about misc syntax. |
| 87 | printf(r.node, "%s", astutil.NodeDescription(r.node)) |
| 88 | } |
| 89 | |
| 90 | func (r *describeUnknownResult) JSON(fset *token.FileSet) []byte { |
| 91 | return toJSON(&serial.Describe{ |
| 92 | Desc: astutil.NodeDescription(r.node), |
| 93 | Pos: fset.Position(r.node.Pos()).String(), |
| 94 | }) |
| 95 | } |
| 96 | |
| 97 | type action int |
| 98 | |
| 99 | const ( |
| 100 | actionUnknown action = iota // None of the below |
| 101 | actionExpr // FuncDecl, true Expr or Ident(types.{Const,Var}) |
| 102 | actionType // type Expr or Ident(types.TypeName). |
| 103 | actionStmt // Stmt or Ident(types.Label) |
| 104 | actionPackage // Ident(types.Package) or ImportSpec |
| 105 | ) |
| 106 | |
| 107 | // findInterestingNode classifies the syntax node denoted by path as one of: |
| 108 | // - an expression, part of an expression or a reference to a constant |
| 109 | // or variable; |
| 110 | // - a type, part of a type, or a reference to a named type; |
| 111 | // - a statement, part of a statement, or a label referring to a statement; |
| 112 | // - part of a package declaration or import spec. |
| 113 | // - none of the above. |
| 114 | // |
| 115 | // and returns the most "interesting" associated node, which may be |
| 116 | // the same node, an ancestor or a descendent. |
| 117 | func findInterestingNode(pkginfo *loader.PackageInfo, path []ast.Node) ([]ast.Node, action) { |
| 118 | // TODO(adonovan): integrate with go/types/stdlib_test.go and |
| 119 | // apply this to every AST node we can find to make sure it |
| 120 | // doesn't crash. |
| 121 | |
| 122 | // TODO(adonovan): audit for ParenExpr safety, esp. since we |
| 123 | // traverse up and down. |
| 124 | |
| 125 | // TODO(adonovan): if the users selects the "." in |
| 126 | // "fmt.Fprintf()", they'll get an ambiguous selection error; |
| 127 | // we won't even reach here. Can we do better? |
| 128 | |
| 129 | // TODO(adonovan): describing a field within 'type T struct {...}' |
| 130 | // describes the (anonymous) struct type and concludes "no methods". |
| 131 | // We should ascend to the enclosing type decl, if any. |
| 132 | |
| 133 | for len(path) > 0 { |
| 134 | switch n := path[0].(type) { |
| 135 | case *ast.GenDecl: |
| 136 | if len(n.Specs) == 1 { |
| 137 | // Descend to sole {Import,Type,Value}Spec child. |
| 138 | path = append([]ast.Node{n.Specs[0]}, path...) |
| 139 | continue |
| 140 | } |
| 141 | return path, actionUnknown // uninteresting |
| 142 | |
| 143 | case *ast.FuncDecl: |
| 144 | // Descend to function name. |
| 145 | path = append([]ast.Node{n.Name}, path...) |
| 146 | continue |
| 147 | |
| 148 | case *ast.ImportSpec: |
| 149 | return path, actionPackage |
| 150 | |
| 151 | case *ast.ValueSpec: |
| 152 | if len(n.Names) == 1 { |
| 153 | // Descend to sole Ident child. |
| 154 | path = append([]ast.Node{n.Names[0]}, path...) |
| 155 | continue |
| 156 | } |
| 157 | return path, actionUnknown // uninteresting |
| 158 | |
| 159 | case *ast.TypeSpec: |
| 160 | // Descend to type name. |
| 161 | path = append([]ast.Node{n.Name}, path...) |
| 162 | continue |
| 163 | |
| 164 | case *ast.Comment, *ast.CommentGroup, *ast.File, *ast.KeyValueExpr, *ast.CommClause: |
| 165 | return path, actionUnknown // uninteresting |
| 166 | |
| 167 | case ast.Stmt: |
| 168 | return path, actionStmt |
| 169 | |
| 170 | case *ast.ArrayType, |
| 171 | *ast.StructType, |
| 172 | *ast.FuncType, |
| 173 | *ast.InterfaceType, |
| 174 | *ast.MapType, |
| 175 | *ast.ChanType: |
| 176 | return path, actionType |
| 177 | |
| 178 | case *ast.Ellipsis: |
| 179 | // Continue to enclosing node. |
| 180 | // e.g. [...]T in ArrayType |
| 181 | // f(x...) in CallExpr |
| 182 | // f(x...T) in FuncType |
| 183 | |
| 184 | case *ast.Field: |
| 185 | // TODO(adonovan): this needs more thought, |
| 186 | // since fields can be so many things. |
| 187 | if len(n.Names) == 1 { |
| 188 | // Descend to sole Ident child. |
| 189 | path = append([]ast.Node{n.Names[0]}, path...) |
| 190 | continue |
| 191 | } |
| 192 | // Zero names (e.g. anon field in struct) |
| 193 | // or multiple field or param names: |
| 194 | // continue to enclosing field list. |
| 195 | |
| 196 | case *ast.FieldList: |
| 197 | // Continue to enclosing node: |
| 198 | // {Struct,Func,Interface}Type or FuncDecl. |
| 199 | |
| 200 | case *ast.BasicLit: |
| 201 | if _, ok := path[1].(*ast.ImportSpec); ok { |
| 202 | return path[1:], actionPackage |
| 203 | } |
| 204 | return path, actionExpr |
| 205 | |
| 206 | case *ast.SelectorExpr: |
| 207 | // TODO(adonovan): use Selections info directly. |
| 208 | if pkginfo.Uses[n.Sel] == nil { |
| 209 | // TODO(adonovan): is this reachable? |
| 210 | return path, actionUnknown |
| 211 | } |
| 212 | // Descend to .Sel child. |
| 213 | path = append([]ast.Node{n.Sel}, path...) |
| 214 | continue |
| 215 | |
| 216 | case *ast.Ident: |
| 217 | switch pkginfo.ObjectOf(n).(type) { |
| 218 | case *types.PkgName: |
| 219 | return path, actionPackage |
| 220 | |
| 221 | case *types.Const: |
| 222 | return path, actionExpr |
| 223 | |
| 224 | case *types.Label: |
| 225 | return path, actionStmt |
| 226 | |
| 227 | case *types.TypeName: |
| 228 | return path, actionType |
| 229 | |
| 230 | case *types.Var: |
| 231 | // For x in 'struct {x T}', return struct type, for now. |
| 232 | if _, ok := path[1].(*ast.Field); ok { |
| 233 | _ = path[2].(*ast.FieldList) // assertion |
| 234 | if _, ok := path[3].(*ast.StructType); ok { |
| 235 | return path[3:], actionType |
| 236 | } |
| 237 | } |
| 238 | return path, actionExpr |
| 239 | |
| 240 | case *types.Func: |
| 241 | return path, actionExpr |
| 242 | |
| 243 | case *types.Builtin: |
| 244 | // For reference to built-in function, return enclosing call. |
| 245 | path = path[1:] // ascend to enclosing function call |
| 246 | continue |
| 247 | |
| 248 | case *types.Nil: |
| 249 | return path, actionExpr |
| 250 | } |
| 251 | |
| 252 | // No object. |
| 253 | switch path[1].(type) { |
| 254 | case *ast.SelectorExpr: |
| 255 | // Return enclosing selector expression. |
| 256 | return path[1:], actionExpr |
| 257 | |
| 258 | case *ast.Field: |
| 259 | // TODO(adonovan): test this. |
| 260 | // e.g. all f in: |
| 261 | // struct { f, g int } |
| 262 | // interface { f() } |
| 263 | // func (f T) method(f, g int) (f, g bool) |
| 264 | // |
| 265 | // switch path[3].(type) { |
| 266 | // case *ast.FuncDecl: |
| 267 | // case *ast.StructType: |
| 268 | // case *ast.InterfaceType: |
| 269 | // } |
| 270 | // |
| 271 | // return path[1:], actionExpr |
| 272 | // |
| 273 | // Unclear what to do with these. |
| 274 | // Struct.Fields -- field |
| 275 | // Interface.Methods -- field |
| 276 | // FuncType.{Params.Results} -- actionExpr |
| 277 | // FuncDecl.Recv -- actionExpr |
| 278 | |
| 279 | case *ast.File: |
| 280 | // 'package foo' |
| 281 | return path, actionPackage |
| 282 | |
| 283 | case *ast.ImportSpec: |
| 284 | return path[1:], actionPackage |
| 285 | |
| 286 | default: |
| 287 | // e.g. blank identifier |
| 288 | // or y in "switch y := x.(type)" |
| 289 | // or code in a _test.go file that's not part of the package. |
| 290 | return path, actionUnknown |
| 291 | } |
| 292 | |
| 293 | case *ast.StarExpr: |
| 294 | if pkginfo.Types[n].IsType() { |
| 295 | return path, actionType |
| 296 | } |
| 297 | return path, actionExpr |
| 298 | |
| 299 | case ast.Expr: |
| 300 | // All Expr but {BasicLit,Ident,StarExpr} are |
| 301 | // "true" expressions that evaluate to a value. |
| 302 | return path, actionExpr |
| 303 | } |
| 304 | |
| 305 | // Ascend to parent. |
| 306 | path = path[1:] |
| 307 | } |
| 308 | |
| 309 | return nil, actionUnknown // unreachable |
| 310 | } |
| 311 | |
| 312 | func describeValue(qpos *queryPos, path []ast.Node) (*describeValueResult, error) { |
| 313 | var expr ast.Expr |
| 314 | var obj types.Object |
| 315 | switch n := path[0].(type) { |
| 316 | case *ast.ValueSpec: |
| 317 | // ambiguous ValueSpec containing multiple names |
| 318 | return nil, fmt.Errorf("multiple value specification") |
| 319 | case *ast.Ident: |
| 320 | obj = qpos.info.ObjectOf(n) |
| 321 | expr = n |
| 322 | case ast.Expr: |
| 323 | expr = n |
| 324 | default: |
| 325 | // TODO(adonovan): is this reachable? |
| 326 | return nil, fmt.Errorf("unexpected AST for expr: %T", n) |
| 327 | } |
| 328 | |
| 329 | typ := qpos.info.TypeOf(expr) |
| 330 | if typ == nil { |
| 331 | typ = types.Typ[types.Invalid] |
| 332 | } |
| 333 | constVal := qpos.info.Types[expr].Value |
| 334 | if c, ok := obj.(*types.Const); ok { |
| 335 | constVal = c.Val() |
| 336 | } |
| 337 | |
| 338 | return &describeValueResult{ |
| 339 | qpos: qpos, |
| 340 | expr: expr, |
| 341 | typ: typ, |
| 342 | names: appendNames(nil, typ), |
| 343 | constVal: constVal, |
| 344 | obj: obj, |
| 345 | methods: accessibleMethods(typ, qpos.info.Pkg), |
| 346 | fields: accessibleFields(typ, qpos.info.Pkg), |
| 347 | }, nil |
| 348 | } |
| 349 | |
| 350 | // appendNames returns named types found within the Type by |
| 351 | // removing map, pointer, channel, slice, and array constructors. |
| 352 | // It does not descend into structs or interfaces. |
| 353 | func appendNames(names []*types.Named, typ types.Type) []*types.Named { |
| 354 | // elemType specifies type that has some element in it |
| 355 | // such as array, slice, chan, pointer |
| 356 | type elemType interface { |
| 357 | Elem() types.Type |
| 358 | } |
| 359 | |
| 360 | switch t := typ.(type) { |
| 361 | case *types.Named: |
| 362 | names = append(names, t) |
| 363 | case *types.Map: |
| 364 | names = appendNames(names, t.Key()) |
| 365 | names = appendNames(names, t.Elem()) |
| 366 | case elemType: |
| 367 | names = appendNames(names, t.Elem()) |
| 368 | } |
| 369 | |
| 370 | return names |
| 371 | } |
| 372 | |
| 373 | type describeValueResult struct { |
| 374 | qpos *queryPos |
| 375 | expr ast.Expr // query node |
| 376 | typ types.Type // type of expression |
| 377 | names []*types.Named // named types within typ |
| 378 | constVal constant.Value // value of expression, if constant |
| 379 | obj types.Object // var/func/const object, if expr was Ident |
| 380 | methods []*types.Selection |
| 381 | fields []describeField |
| 382 | } |
| 383 | |
| 384 | func (r *describeValueResult) PrintPlain(printf printfFunc) { |
| 385 | var prefix, suffix string |
| 386 | if r.constVal != nil { |
| 387 | suffix = fmt.Sprintf(" of value %s", r.constVal) |
| 388 | } |
| 389 | switch obj := r.obj.(type) { |
| 390 | case *types.Func: |
| 391 | if recv := obj.Type().(*types.Signature).Recv(); recv != nil { |
| 392 | if _, ok := recv.Type().Underlying().(*types.Interface); ok { |
| 393 | prefix = "interface method " |
| 394 | } else { |
| 395 | prefix = "method " |
| 396 | } |
| 397 | } |
| 398 | } |
| 399 | |
| 400 | // Describe the expression. |
| 401 | if r.obj != nil { |
| 402 | if r.obj.Pos() == r.expr.Pos() { |
| 403 | // defining ident |
| 404 | printf(r.expr, "definition of %s%s%s", prefix, r.qpos.objectString(r.obj), suffix) |
| 405 | } else { |
| 406 | // referring ident |
| 407 | printf(r.expr, "reference to %s%s%s", prefix, r.qpos.objectString(r.obj), suffix) |
| 408 | if def := r.obj.Pos(); def != token.NoPos { |
| 409 | printf(def, "defined here") |
| 410 | } |
| 411 | } |
| 412 | } else { |
| 413 | desc := astutil.NodeDescription(r.expr) |
| 414 | if suffix != "" { |
| 415 | // constant expression |
| 416 | printf(r.expr, "%s%s", desc, suffix) |
| 417 | } else { |
| 418 | // non-constant expression |
| 419 | printf(r.expr, "%s of type %s", desc, r.qpos.typeString(r.typ)) |
| 420 | } |
| 421 | } |
| 422 | |
| 423 | printMethods(printf, r.expr, r.methods) |
| 424 | printFields(printf, r.expr, r.fields) |
| 425 | printNamedTypes(printf, r.expr, r.names) |
| 426 | } |
| 427 | |
| 428 | func (r *describeValueResult) JSON(fset *token.FileSet) []byte { |
| 429 | var value, objpos string |
| 430 | if r.constVal != nil { |
| 431 | value = r.constVal.String() |
| 432 | } |
| 433 | if r.obj != nil { |
| 434 | objpos = fset.Position(r.obj.Pos()).String() |
| 435 | } |
| 436 | |
| 437 | typesPos := make([]serial.Definition, len(r.names)) |
| 438 | for i, t := range r.names { |
| 439 | typesPos[i] = serial.Definition{ |
| 440 | ObjPos: fset.Position(t.Obj().Pos()).String(), |
| 441 | Desc: r.qpos.typeString(t), |
| 442 | } |
| 443 | } |
| 444 | |
| 445 | return toJSON(&serial.Describe{ |
| 446 | Desc: astutil.NodeDescription(r.expr), |
| 447 | Pos: fset.Position(r.expr.Pos()).String(), |
| 448 | Detail: "value", |
| 449 | Value: &serial.DescribeValue{ |
| 450 | Type: r.qpos.typeString(r.typ), |
| 451 | TypesPos: typesPos, |
| 452 | Value: value, |
| 453 | ObjPos: objpos, |
| 454 | }, |
| 455 | }) |
| 456 | } |
| 457 | |
| 458 | // ---- TYPE ------------------------------------------------------------ |
| 459 | |
| 460 | func describeType(qpos *queryPos, path []ast.Node) (*describeTypeResult, error) { |
| 461 | var description string |
| 462 | var typ types.Type |
| 463 | switch n := path[0].(type) { |
| 464 | case *ast.Ident: |
| 465 | obj := qpos.info.ObjectOf(n).(*types.TypeName) |
| 466 | typ = obj.Type() |
| 467 | if isAlias(obj) { |
| 468 | description = "alias of " |
| 469 | } else if obj.Pos() == n.Pos() { |
| 470 | description = "definition of " // (Named type) |
| 471 | } else if _, ok := typ.(*types.Basic); ok { |
| 472 | description = "reference to built-in " |
| 473 | } else { |
| 474 | description = "reference to " // (Named type) |
| 475 | } |
| 476 | |
| 477 | case ast.Expr: |
| 478 | typ = qpos.info.TypeOf(n) |
| 479 | |
| 480 | default: |
| 481 | // Unreachable? |
| 482 | return nil, fmt.Errorf("unexpected AST for type: %T", n) |
| 483 | } |
| 484 | |
| 485 | description = description + "type " + qpos.typeString(typ) |
| 486 | |
| 487 | // Show sizes for structs and named types (it's fairly obvious for others). |
| 488 | switch typ.(type) { |
| 489 | case *types.Named, *types.Struct: |
| 490 | szs := types.StdSizes{WordSize: 8, MaxAlign: 8} // assume amd64 |
| 491 | description = fmt.Sprintf("%s (size %d, align %d)", description, |
| 492 | szs.Sizeof(typ), szs.Alignof(typ)) |
| 493 | } |
| 494 | |
| 495 | return &describeTypeResult{ |
| 496 | qpos: qpos, |
| 497 | node: path[0], |
| 498 | description: description, |
| 499 | typ: typ, |
| 500 | methods: accessibleMethods(typ, qpos.info.Pkg), |
| 501 | fields: accessibleFields(typ, qpos.info.Pkg), |
| 502 | }, nil |
| 503 | } |
| 504 | |
| 505 | type describeTypeResult struct { |
| 506 | qpos *queryPos |
| 507 | node ast.Node |
| 508 | description string |
| 509 | typ types.Type |
| 510 | methods []*types.Selection |
| 511 | fields []describeField |
| 512 | } |
| 513 | |
| 514 | type describeField struct { |
| 515 | implicits []*types.Named |
| 516 | field *types.Var |
| 517 | } |
| 518 | |
| 519 | func printMethods(printf printfFunc, node ast.Node, methods []*types.Selection) { |
| 520 | if len(methods) > 0 { |
| 521 | printf(node, "Methods:") |
| 522 | } |
| 523 | for _, meth := range methods { |
| 524 | // Print the method type relative to the package |
| 525 | // in which it was defined, not the query package, |
| 526 | printf(meth.Obj(), "\t%s", |
| 527 | types.SelectionString(meth, types.RelativeTo(meth.Obj().Pkg()))) |
| 528 | } |
| 529 | } |
| 530 | |
| 531 | func printFields(printf printfFunc, node ast.Node, fields []describeField) { |
| 532 | if len(fields) > 0 { |
| 533 | printf(node, "Fields:") |
| 534 | } |
| 535 | |
| 536 | // Align the names and the types (requires two passes). |
| 537 | var width int |
| 538 | var names []string |
| 539 | for _, f := range fields { |
| 540 | var buf bytes.Buffer |
| 541 | for _, fld := range f.implicits { |
| 542 | buf.WriteString(fld.Obj().Name()) |
| 543 | buf.WriteByte('.') |
| 544 | } |
| 545 | buf.WriteString(f.field.Name()) |
| 546 | name := buf.String() |
| 547 | if n := utf8.RuneCountInString(name); n > width { |
| 548 | width = n |
| 549 | } |
| 550 | names = append(names, name) |
| 551 | } |
| 552 | |
| 553 | for i, f := range fields { |
| 554 | // Print the field type relative to the package |
| 555 | // in which it was defined, not the query package, |
| 556 | printf(f.field, "\t%*s %s", -width, names[i], |
| 557 | types.TypeString(f.field.Type(), types.RelativeTo(f.field.Pkg()))) |
| 558 | } |
| 559 | } |
| 560 | |
| 561 | func printNamedTypes(printf printfFunc, node ast.Node, names []*types.Named) { |
| 562 | if len(names) > 0 { |
| 563 | printf(node, "Named types:") |
| 564 | } |
| 565 | |
| 566 | for _, t := range names { |
| 567 | // Print the type relative to the package |
| 568 | // in which it was defined, not the query package, |
| 569 | printf(t.Obj(), "\ttype %s defined here", |
| 570 | types.TypeString(t.Obj().Type(), types.RelativeTo(t.Obj().Pkg()))) |
| 571 | } |
| 572 | } |
| 573 | |
| 574 | func (r *describeTypeResult) PrintPlain(printf printfFunc) { |
| 575 | printf(r.node, "%s", r.description) |
| 576 | |
| 577 | // Show the underlying type for a reference to a named type. |
| 578 | if nt, ok := r.typ.(*types.Named); ok && r.node.Pos() != nt.Obj().Pos() { |
| 579 | // TODO(adonovan): improve display of complex struct/interface types. |
| 580 | printf(nt.Obj(), "defined as %s", r.qpos.typeString(nt.Underlying())) |
| 581 | } |
| 582 | |
| 583 | printMethods(printf, r.node, r.methods) |
| 584 | if len(r.methods) == 0 { |
| 585 | // Only report null result for type kinds |
| 586 | // capable of bearing methods. |
| 587 | switch r.typ.(type) { |
| 588 | case *types.Interface, *types.Struct, *types.Named: |
| 589 | printf(r.node, "No methods.") |
| 590 | } |
| 591 | } |
| 592 | |
| 593 | printFields(printf, r.node, r.fields) |
| 594 | } |
| 595 | |
| 596 | func (r *describeTypeResult) JSON(fset *token.FileSet) []byte { |
| 597 | var namePos, nameDef string |
| 598 | if nt, ok := r.typ.(*types.Named); ok { |
| 599 | namePos = fset.Position(nt.Obj().Pos()).String() |
| 600 | nameDef = nt.Underlying().String() |
| 601 | } |
| 602 | return toJSON(&serial.Describe{ |
| 603 | Desc: r.description, |
| 604 | Pos: fset.Position(r.node.Pos()).String(), |
| 605 | Detail: "type", |
| 606 | Type: &serial.DescribeType{ |
| 607 | Type: r.qpos.typeString(r.typ), |
| 608 | NamePos: namePos, |
| 609 | NameDef: nameDef, |
| 610 | Methods: methodsToSerial(r.qpos.info.Pkg, r.methods, fset), |
| 611 | }, |
| 612 | }) |
| 613 | } |
| 614 | |
| 615 | // ---- PACKAGE ------------------------------------------------------------ |
| 616 | |
| 617 | func describePackage(qpos *queryPos, path []ast.Node) (*describePackageResult, error) { |
| 618 | var description string |
| 619 | var pkg *types.Package |
| 620 | switch n := path[0].(type) { |
| 621 | case *ast.ImportSpec: |
| 622 | var obj types.Object |
| 623 | if n.Name != nil { |
| 624 | obj = qpos.info.Defs[n.Name] |
| 625 | } else { |
| 626 | obj = qpos.info.Implicits[n] |
| 627 | } |
| 628 | pkgname, _ := obj.(*types.PkgName) |
| 629 | if pkgname == nil { |
| 630 | return nil, fmt.Errorf("can't import package %s", n.Path.Value) |
| 631 | } |
| 632 | pkg = pkgname.Imported() |
| 633 | description = fmt.Sprintf("import of package %q", pkg.Path()) |
| 634 | |
| 635 | case *ast.Ident: |
| 636 | if _, isDef := path[1].(*ast.File); isDef { |
| 637 | // e.g. package id |
| 638 | pkg = qpos.info.Pkg |
| 639 | description = fmt.Sprintf("definition of package %q", pkg.Path()) |
| 640 | } else { |
| 641 | // e.g. import id "..." |
| 642 | // or id.F() |
| 643 | pkg = qpos.info.ObjectOf(n).(*types.PkgName).Imported() |
| 644 | description = fmt.Sprintf("reference to package %q", pkg.Path()) |
| 645 | } |
| 646 | |
| 647 | default: |
| 648 | // Unreachable? |
| 649 | return nil, fmt.Errorf("unexpected AST for package: %T", n) |
| 650 | } |
| 651 | |
| 652 | var members []*describeMember |
| 653 | // NB: "unsafe" has no types.Package |
| 654 | if pkg != nil { |
| 655 | // Enumerate the accessible package members |
| 656 | // in lexicographic order. |
| 657 | for _, name := range pkg.Scope().Names() { |
| 658 | if pkg == qpos.info.Pkg || ast.IsExported(name) { |
| 659 | mem := pkg.Scope().Lookup(name) |
| 660 | var methods []*types.Selection |
| 661 | if mem, ok := mem.(*types.TypeName); ok { |
| 662 | methods = accessibleMethods(mem.Type(), qpos.info.Pkg) |
| 663 | } |
| 664 | members = append(members, &describeMember{ |
| 665 | mem, |
| 666 | methods, |
| 667 | }) |
| 668 | |
| 669 | } |
| 670 | } |
| 671 | } |
| 672 | |
| 673 | return &describePackageResult{qpos.fset, path[0], description, pkg, members}, nil |
| 674 | } |
| 675 | |
| 676 | type describePackageResult struct { |
| 677 | fset *token.FileSet |
| 678 | node ast.Node |
| 679 | description string |
| 680 | pkg *types.Package |
| 681 | members []*describeMember // in lexicographic name order |
| 682 | } |
| 683 | |
| 684 | type describeMember struct { |
| 685 | obj types.Object |
| 686 | methods []*types.Selection // in types.MethodSet order |
| 687 | } |
| 688 | |
| 689 | func (r *describePackageResult) PrintPlain(printf printfFunc) { |
| 690 | printf(r.node, "%s", r.description) |
| 691 | |
| 692 | // Compute max width of name "column". |
| 693 | maxname := 0 |
| 694 | for _, mem := range r.members { |
| 695 | if l := len(mem.obj.Name()); l > maxname { |
| 696 | maxname = l |
| 697 | } |
| 698 | } |
| 699 | |
| 700 | for _, mem := range r.members { |
| 701 | printf(mem.obj, "\t%s", formatMember(mem.obj, maxname)) |
| 702 | for _, meth := range mem.methods { |
| 703 | printf(meth.Obj(), "\t\t%s", types.SelectionString(meth, types.RelativeTo(r.pkg))) |
| 704 | } |
| 705 | } |
| 706 | } |
| 707 | |
| 708 | func formatMember(obj types.Object, maxname int) string { |
| 709 | qualifier := types.RelativeTo(obj.Pkg()) |
| 710 | var buf bytes.Buffer |
| 711 | fmt.Fprintf(&buf, "%-5s %-*s", tokenOf(obj), maxname, obj.Name()) |
| 712 | switch obj := obj.(type) { |
| 713 | case *types.Const: |
| 714 | fmt.Fprintf(&buf, " %s = %s", types.TypeString(obj.Type(), qualifier), obj.Val()) |
| 715 | |
| 716 | case *types.Func: |
| 717 | fmt.Fprintf(&buf, " %s", types.TypeString(obj.Type(), qualifier)) |
| 718 | |
| 719 | case *types.TypeName: |
| 720 | typ := obj.Type() |
| 721 | if isAlias(obj) { |
| 722 | buf.WriteString(" = ") |
| 723 | } else { |
| 724 | buf.WriteByte(' ') |
| 725 | typ = typ.Underlying() |
| 726 | } |
| 727 | var typestr string |
| 728 | // Abbreviate long aggregate type names. |
| 729 | switch typ := typ.(type) { |
| 730 | case *types.Interface: |
| 731 | if typ.NumMethods() > 1 { |
| 732 | typestr = "interface{...}" |
| 733 | } |
| 734 | case *types.Struct: |
| 735 | if typ.NumFields() > 1 { |
| 736 | typestr = "struct{...}" |
| 737 | } |
| 738 | } |
| 739 | if typestr == "" { |
| 740 | // The fix for #44515 changed the printing of unsafe.Pointer |
| 741 | // such that it uses a qualifier if one is provided. Using |
| 742 | // the types.RelativeTo qualifier provided here, the output |
| 743 | // is just "Pointer" rather than "unsafe.Pointer". This is |
| 744 | // consistent with the printing of non-type objects but it |
| 745 | // breaks an existing test which needs to work with older |
| 746 | // versions of Go. Re-establish the original output by not |
| 747 | // using a qualifier at all if we're printing a type from |
| 748 | // package unsafe - there's only unsafe.Pointer (#44596). |
| 749 | // NOTE: This correction can be removed (and the test's |
| 750 | // golden file adjusted) once we only run against go1.17 |
| 751 | // or bigger. |
| 752 | qualifier := qualifier |
| 753 | if obj.Pkg() == types.Unsafe { |
| 754 | qualifier = nil |
| 755 | } |
| 756 | typestr = types.TypeString(typ, qualifier) |
| 757 | } |
| 758 | buf.WriteString(typestr) |
| 759 | |
| 760 | case *types.Var: |
| 761 | fmt.Fprintf(&buf, " %s", types.TypeString(obj.Type(), qualifier)) |
| 762 | } |
| 763 | return buf.String() |
| 764 | } |
| 765 | |
| 766 | func (r *describePackageResult) JSON(fset *token.FileSet) []byte { |
| 767 | var members []*serial.DescribeMember |
| 768 | for _, mem := range r.members { |
| 769 | obj := mem.obj |
| 770 | typ := obj.Type() |
| 771 | var val string |
| 772 | var alias string |
| 773 | switch obj := obj.(type) { |
| 774 | case *types.Const: |
| 775 | val = obj.Val().String() |
| 776 | case *types.TypeName: |
| 777 | if isAlias(obj) { |
| 778 | alias = "= " // kludgy |
| 779 | } else { |
| 780 | typ = typ.Underlying() |
| 781 | } |
| 782 | } |
| 783 | members = append(members, &serial.DescribeMember{ |
| 784 | Name: obj.Name(), |
| 785 | Type: alias + typ.String(), |
| 786 | Value: val, |
| 787 | Pos: fset.Position(obj.Pos()).String(), |
| 788 | Kind: tokenOf(obj), |
| 789 | Methods: methodsToSerial(r.pkg, mem.methods, fset), |
| 790 | }) |
| 791 | } |
| 792 | return toJSON(&serial.Describe{ |
| 793 | Desc: r.description, |
| 794 | Pos: fset.Position(r.node.Pos()).String(), |
| 795 | Detail: "package", |
| 796 | Package: &serial.DescribePackage{ |
| 797 | Path: r.pkg.Path(), |
| 798 | Members: members, |
| 799 | }, |
| 800 | }) |
| 801 | } |
| 802 | |
| 803 | func tokenOf(o types.Object) string { |
| 804 | switch o.(type) { |
| 805 | case *types.Func: |
| 806 | return "func" |
| 807 | case *types.Var: |
| 808 | return "var" |
| 809 | case *types.TypeName: |
| 810 | return "type" |
| 811 | case *types.Const: |
| 812 | return "const" |
| 813 | case *types.PkgName: |
| 814 | return "package" |
| 815 | case *types.Builtin: |
| 816 | return "builtin" // e.g. when describing package "unsafe" |
| 817 | case *types.Nil: |
| 818 | return "nil" |
| 819 | case *types.Label: |
| 820 | return "label" |
| 821 | } |
| 822 | panic(o) |
| 823 | } |
| 824 | |
| 825 | // ---- STATEMENT ------------------------------------------------------------ |
| 826 | |
| 827 | func describeStmt(qpos *queryPos, path []ast.Node) (*describeStmtResult, error) { |
| 828 | var description string |
| 829 | switch n := path[0].(type) { |
| 830 | case *ast.Ident: |
| 831 | if qpos.info.Defs[n] != nil { |
| 832 | description = "labelled statement" |
| 833 | } else { |
| 834 | description = "reference to labelled statement" |
| 835 | } |
| 836 | |
| 837 | default: |
| 838 | // Nothing much to say about statements. |
| 839 | description = astutil.NodeDescription(n) |
| 840 | } |
| 841 | return &describeStmtResult{qpos.fset, path[0], description}, nil |
| 842 | } |
| 843 | |
| 844 | type describeStmtResult struct { |
| 845 | fset *token.FileSet |
| 846 | node ast.Node |
| 847 | description string |
| 848 | } |
| 849 | |
| 850 | func (r *describeStmtResult) PrintPlain(printf printfFunc) { |
| 851 | printf(r.node, "%s", r.description) |
| 852 | } |
| 853 | |
| 854 | func (r *describeStmtResult) JSON(fset *token.FileSet) []byte { |
| 855 | return toJSON(&serial.Describe{ |
| 856 | Desc: r.description, |
| 857 | Pos: fset.Position(r.node.Pos()).String(), |
| 858 | Detail: "unknown", |
| 859 | }) |
| 860 | } |
| 861 | |
| 862 | // ------------------- Utilities ------------------- |
| 863 | |
| 864 | // pathToString returns a string containing the concrete types of the |
| 865 | // nodes in path. |
| 866 | func pathToString(path []ast.Node) string { |
| 867 | var buf bytes.Buffer |
| 868 | fmt.Fprint(&buf, "[") |
| 869 | for i, n := range path { |
| 870 | if i > 0 { |
| 871 | fmt.Fprint(&buf, " ") |
| 872 | } |
| 873 | fmt.Fprint(&buf, strings.TrimPrefix(fmt.Sprintf("%T", n), "*ast.")) |
| 874 | } |
| 875 | fmt.Fprint(&buf, "]") |
| 876 | return buf.String() |
| 877 | } |
| 878 | |
| 879 | func accessibleMethods(t types.Type, from *types.Package) []*types.Selection { |
| 880 | var methods []*types.Selection |
| 881 | for _, meth := range typeutil.IntuitiveMethodSet(t, nil) { |
| 882 | if isAccessibleFrom(meth.Obj(), from) { |
| 883 | methods = append(methods, meth) |
| 884 | } |
| 885 | } |
| 886 | return methods |
| 887 | } |
| 888 | |
| 889 | // accessibleFields returns the set of accessible |
| 890 | // field selections on a value of type recv. |
| 891 | func accessibleFields(recv types.Type, from *types.Package) []describeField { |
| 892 | wantField := func(f *types.Var) bool { |
| 893 | if !isAccessibleFrom(f, from) { |
| 894 | return false |
| 895 | } |
| 896 | // Check that the field is not shadowed. |
| 897 | obj, _, _ := types.LookupFieldOrMethod(recv, true, f.Pkg(), f.Name()) |
| 898 | return obj == f |
| 899 | } |
| 900 | |
| 901 | var fields []describeField |
| 902 | var visit func(t types.Type, stack []*types.Named) |
| 903 | visit = func(t types.Type, stack []*types.Named) { |
| 904 | tStruct, ok := deref(t).Underlying().(*types.Struct) |
| 905 | if !ok { |
| 906 | return |
| 907 | } |
| 908 | fieldloop: |
| 909 | for i := 0; i < tStruct.NumFields(); i++ { |
| 910 | f := tStruct.Field(i) |
| 911 | |
| 912 | // Handle recursion through anonymous fields. |
| 913 | if f.Anonymous() { |
| 914 | tf := f.Type() |
| 915 | if ptr, ok := tf.(*types.Pointer); ok { |
| 916 | tf = ptr.Elem() |
| 917 | } |
| 918 | if named, ok := tf.(*types.Named); ok { // (be defensive) |
| 919 | // If we've already visited this named type |
| 920 | // on this path, break the cycle. |
| 921 | for _, x := range stack { |
| 922 | if x == named { |
| 923 | continue fieldloop |
| 924 | } |
| 925 | } |
| 926 | visit(f.Type(), append(stack, named)) |
| 927 | } |
| 928 | } |
| 929 | |
| 930 | // Save accessible fields. |
| 931 | if wantField(f) { |
| 932 | fields = append(fields, describeField{ |
| 933 | implicits: append([]*types.Named(nil), stack...), |
| 934 | field: f, |
| 935 | }) |
| 936 | } |
| 937 | } |
| 938 | } |
| 939 | visit(recv, nil) |
| 940 | |
| 941 | return fields |
| 942 | } |
| 943 | |
| 944 | func isAccessibleFrom(obj types.Object, pkg *types.Package) bool { |
| 945 | return ast.IsExported(obj.Name()) || obj.Pkg() == pkg |
| 946 | } |
| 947 | |
| 948 | func methodsToSerial(this *types.Package, methods []*types.Selection, fset *token.FileSet) []serial.DescribeMethod { |
| 949 | qualifier := types.RelativeTo(this) |
| 950 | var jmethods []serial.DescribeMethod |
| 951 | for _, meth := range methods { |
| 952 | var ser serial.DescribeMethod |
| 953 | if meth != nil { // may contain nils when called by implements (on a method) |
| 954 | ser = serial.DescribeMethod{ |
| 955 | Name: types.SelectionString(meth, qualifier), |
| 956 | Pos: fset.Position(meth.Obj().Pos()).String(), |
| 957 | } |
| 958 | } |
| 959 | jmethods = append(jmethods, ser) |
| 960 | } |
| 961 | return jmethods |
| 962 | } |
| 963 |
Members