mirror of
https://github.com/golang/go
synced 2024-11-18 14:14:46 -07:00
fb3df4a89d
The parser does intra-file resolution. It's only a best-effort but it's extremely fast, so we try it first and fall back to the loader-based implementation if it fails. Also: - factor definitionResult so it doesn't depend on either go/types.Object or go/ast.Object. - guessImportPath: make importPath=="" result an error, since you can't import the empty string. Simplify importQueryPackage. - Make fastQueryPos continue in face of minor parse errors. - describe: eliminate old TODO; suppress log statement. Change-Id: I30a32487e9fd9d5308b1580ec12220cad2c16299 Reviewed-on: https://go-review.googlesource.com/19507 Reviewed-by: Daniel Morsing <daniel.morsing@gmail.com>
103 lines
2.3 KiB
Go
103 lines
2.3 KiB
Go
// Copyright 2013 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package main
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import (
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"fmt"
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"go/ast"
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"go/token"
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"golang.org/x/tools/cmd/guru/serial"
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"golang.org/x/tools/go/loader"
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)
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// definition reports the location of the definition of an identifier.
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func definition(q *Query) error {
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// First try the simple resolution done by parser.
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// It only works for intra-file references but it is very fast.
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// (Extending this approach to all the files of the package,
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// resolved using ast.NewPackage, was not worth the effort.)
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{
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qpos, err := fastQueryPos(q.Pos)
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if err != nil {
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return err
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}
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id, _ := qpos.path[0].(*ast.Ident)
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if id == nil {
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return fmt.Errorf("no identifier here")
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}
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if obj := id.Obj; obj != nil && obj.Pos().IsValid() {
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q.Fset = qpos.fset
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q.result = &definitionResult{
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pos: obj.Pos(),
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descr: fmt.Sprintf("%s %s", obj.Kind, obj.Name),
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}
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return nil // success
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}
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}
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// Run the type checker.
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lconf := loader.Config{Build: q.Build}
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allowErrors(&lconf)
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if _, err := importQueryPackage(q.Pos, &lconf); err != nil {
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return err
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}
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// Load/parse/type-check the program.
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lprog, err := lconf.Load()
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if err != nil {
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return err
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}
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q.Fset = lprog.Fset
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qpos, err := parseQueryPos(lprog, q.Pos, false)
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if err != nil {
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return err
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}
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id, _ := qpos.path[0].(*ast.Ident)
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if id == nil {
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return fmt.Errorf("no identifier here")
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}
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obj := qpos.info.ObjectOf(id)
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if obj == nil {
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// Happens for y in "switch y := x.(type)",
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// and the package declaration,
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// but I think that's all.
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return fmt.Errorf("no object for identifier")
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}
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if !obj.Pos().IsValid() {
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return fmt.Errorf("%s is built in", obj.Name())
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}
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q.result = &definitionResult{
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pos: obj.Pos(),
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descr: qpos.objectString(obj),
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}
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return nil
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}
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type definitionResult struct {
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pos token.Pos // (nonzero) location of definition
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descr string // description of object it denotes
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}
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func (r *definitionResult) display(printf printfFunc) {
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printf(r.pos, "defined here as %s", r.descr)
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}
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func (r *definitionResult) toSerial(res *serial.Result, fset *token.FileSet) {
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definition := &serial.Definition{
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Desc: r.descr,
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ObjPos: fset.Position(r.pos).String(),
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}
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res.Definition = definition
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}
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