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go/internal/lsp/source/definition.go
Ian Cottrell fc2e60c3c3 internal/lsp: make Definition handle embedded fields
This change allows it to jump to the type if you are directly on the
embedded field when you trigger go to definition.

Change-Id: I48825a5a683e69c0714978c76b1d188d40b38c5d
Reviewed-on: https://go-review.googlesource.com/c/149615
Run-TryBot: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
2018-11-15 19:04:06 +00:00

96 lines
2.4 KiB
Go

// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package source
import (
"context"
"fmt"
"go/ast"
"go/token"
"go/types"
"golang.org/x/tools/go/ast/astutil"
)
func Definition(ctx context.Context, f *File, pos token.Pos) (Range, error) {
fAST, err := f.GetAST()
if err != nil {
return Range{}, err
}
pkg, err := f.GetPackage()
if err != nil {
return Range{}, err
}
i, err := findIdentifier(fAST, pos)
if err != nil {
return Range{}, err
}
if i.ident == nil {
return Range{}, fmt.Errorf("definition was not a valid identifier")
}
obj := pkg.TypesInfo.ObjectOf(i.ident)
if obj == nil {
return Range{}, fmt.Errorf("no object")
}
if i.wasEmbeddedField {
// the original position was on the embedded field declaration
// so we try to dig out the type and jump to that instead
if v, ok := obj.(*types.Var); ok {
if n, ok := v.Type().(*types.Named); ok {
obj = n.Obj()
}
}
}
return Range{
Start: obj.Pos(),
End: obj.Pos() + token.Pos(len([]byte(obj.Name()))), // TODO: use real range of obj
}, nil
}
// ident returns the ident plus any extra information needed
type ident struct {
ident *ast.Ident
wasEmbeddedField bool
}
// findIdentifier returns the ast.Ident for a position
// in a file, accounting for a potentially incomplete selector.
func findIdentifier(f *ast.File, pos token.Pos) (ident, error) {
m, err := checkIdentifier(f, pos)
if err != nil {
return ident{}, err
}
if m.ident != nil {
return m, nil
}
// If the position is not an identifier but immediately follows
// an identifier or selector period (as is common when
// requesting a completion), use the path to the preceding node.
return checkIdentifier(f, pos-1)
}
// checkIdentifier checks a single position for a potential identifier.
func checkIdentifier(f *ast.File, pos token.Pos) (ident, error) {
path, _ := astutil.PathEnclosingInterval(f, pos, pos)
result := ident{}
if path == nil {
return result, fmt.Errorf("can't find node enclosing position")
}
switch node := path[0].(type) {
case *ast.Ident:
result.ident = node
case *ast.SelectorExpr:
result.ident = node.Sel
}
if result.ident != nil {
for _, n := range path[1:] {
if field, ok := n.(*ast.Field); ok {
result.wasEmbeddedField = len(field.Names) == 0
}
}
}
return result, nil
}