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go/internal/lsp/source/references.go
Ian Cottrell 4457e4cfd4 internal/lsp: add some trace spans to important functions
This uses the new opencensus compatability layer to add telementry to some of
the functions in the lsp, in order to allow us to understand their costs and
call patterns.

Change-Id: I7df820cd4eace7a4840ac6397d5df402369bf0a7
Reviewed-on: https://go-review.googlesource.com/c/tools/+/183419
Run-TryBot: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
2019-07-03 19:14:57 +00:00

88 lines
2.6 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
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, ts := trace.StartSpan(ctx, "source.References")
defer ts.End()
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")
}
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,
isDeclaration: true,
})
}
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())
}
for ident, obj := range info.Defs {
// TODO(suzmue): support the case where an identifier may have two different declarations.
if obj == nil || obj.Pos() != i.decl.obj.Pos() {
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,
isDeclaration: true,
}}, references...)
}
for ident, obj := range info.Uses {
if obj == nil || obj.Pos() != i.decl.obj.Pos() {
continue
}
references = append(references, &ReferenceInfo{
Name: ident.Name,
Range: span.NewRange(i.File.FileSet(), ident.Pos(), ident.End()),
ident: ident,
obj: obj,
})
}
}
return references, nil
}