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go/internal/lsp/source/references.go
Ian Cottrell 75aaabac35 internal/lsp: reduce trace package to minimal StartSpan for now
also change the return type to be and end function and not an incomplete span

Change-Id: Icd99d93ac98a0f8088f33e905cf1ee3fe410c024
Reviewed-on: https://go-review.googlesource.com/c/tools/+/185349
Run-TryBot: Ian Cottrell <iancottrell@google.com>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
2019-07-11 17:25:55 +00:00

100 lines
2.9 KiB
Go

// Copyright 2019 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/types"
"golang.org/x/tools/internal/lsp/telemetry/trace"
"golang.org/x/tools/internal/span"
)
// ReferenceInfo holds information about reference to an identifier in Go source.
type ReferenceInfo struct {
Name string
Range span.Range
ident *ast.Ident
obj types.Object
pkg Package
isDeclaration bool
}
// References returns a list of references for a given identifier within the packages
// containing i.File. Declarations appear first in the result.
func (i *IdentifierInfo) References(ctx context.Context) ([]*ReferenceInfo, error) {
ctx, done := trace.StartSpan(ctx, "source.References")
defer done()
var references []*ReferenceInfo
// If the object declaration is nil, assume it is an import spec and do not look for references.
if i.decl.obj == nil {
return nil, fmt.Errorf("no references for an import spec")
}
pkgs := i.File.GetPackages(ctx)
for _, pkg := range pkgs {
if pkg == nil || pkg.IsIllTyped() {
return nil, fmt.Errorf("package for %s is ill typed", i.File.URI())
}
info := pkg.GetTypesInfo()
if info == nil {
return nil, fmt.Errorf("package %s has no types info", pkg.PkgPath())
}
if i.decl.wasImplicit {
// The definition is implicit, so we must add it separately.
// This occurs when the variable is declared in a type switch statement
// or is an implicit package name. Both implicits are local to a file.
references = append(references, &ReferenceInfo{
Name: i.decl.obj.Name(),
Range: i.decl.rng,
obj: i.decl.obj,
pkg: pkg,
isDeclaration: true,
})
}
for ident, obj := range info.Defs {
if obj == nil || !sameObj(obj, i.decl.obj) {
continue
}
// Add the declarations at the beginning of the references list.
references = append([]*ReferenceInfo{&ReferenceInfo{
Name: ident.Name,
Range: span.NewRange(i.File.FileSet(), ident.Pos(), ident.End()),
ident: ident,
obj: obj,
pkg: pkg,
isDeclaration: true,
}}, references...)
}
for ident, obj := range info.Uses {
if obj == nil || !sameObj(obj, i.decl.obj) {
continue
}
references = append(references, &ReferenceInfo{
Name: ident.Name,
Range: span.NewRange(i.File.FileSet(), ident.Pos(), ident.End()),
ident: ident,
pkg: pkg,
obj: obj,
})
}
}
return references, nil
}
// sameObj returns true if obj is the same as declObj.
// Objects are the same if they have the some Pos and Name.
func sameObj(obj, declObj types.Object) bool {
// TODO(suzmue): support the case where an identifier may have two different
// declaration positions.
return obj.Pos() == declObj.Pos() && obj.Name() == declObj.Name()
}