331 lines
8.9 KiB
Go
331 lines
8.9 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 oracle
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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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"reflect"
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"sort"
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"strings"
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"golang.org/x/tools/go/loader"
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"golang.org/x/tools/go/types"
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"golang.org/x/tools/go/types/typeutil"
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"golang.org/x/tools/oracle/serial"
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)
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// Implements displays the "implements" relation as it pertains to the
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// selected type within a single package.
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// If the selection is a method, 'implements' displays
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// the corresponding methods of the types that would have been reported
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// by an implements query on the receiver type.
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//
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func implements(q *Query) error {
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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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// Find the selected type.
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path, action := findInterestingNode(qpos.info, qpos.path)
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var method *types.Func
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var T types.Type // selected type (receiver if method != nil)
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switch action {
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case actionExpr:
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// method?
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if id, ok := path[0].(*ast.Ident); ok {
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if obj, ok := qpos.info.ObjectOf(id).(*types.Func); ok {
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recv := obj.Type().(*types.Signature).Recv()
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if recv == nil {
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return fmt.Errorf("this function is not a method")
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}
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method = obj
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T = recv.Type()
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}
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}
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case actionType:
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T = qpos.info.TypeOf(path[0].(ast.Expr))
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}
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if T == nil {
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return fmt.Errorf("no type or method here")
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}
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// Find all named types, even local types (which can have
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// methods via promotion) and the built-in "error".
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//
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// TODO(adonovan): include all packages in PTA scope too?
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// i.e. don't reduceScope?
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//
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var allNamed []types.Type
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for _, info := range lprog.AllPackages {
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for _, obj := range info.Defs {
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if obj, ok := obj.(*types.TypeName); ok {
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allNamed = append(allNamed, obj.Type())
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}
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}
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}
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allNamed = append(allNamed, types.Universe.Lookup("error").Type())
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var msets typeutil.MethodSetCache
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// Test each named type.
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var to, from, fromPtr []types.Type
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for _, U := range allNamed {
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if isInterface(T) {
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if msets.MethodSet(T).Len() == 0 {
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continue // empty interface
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}
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if isInterface(U) {
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if msets.MethodSet(U).Len() == 0 {
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continue // empty interface
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}
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// T interface, U interface
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if !types.Identical(T, U) {
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if types.AssignableTo(U, T) {
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to = append(to, U)
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}
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if types.AssignableTo(T, U) {
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from = append(from, U)
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}
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}
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} else {
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// T interface, U concrete
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if types.AssignableTo(U, T) {
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to = append(to, U)
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} else if pU := types.NewPointer(U); types.AssignableTo(pU, T) {
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to = append(to, pU)
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}
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}
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} else if isInterface(U) {
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if msets.MethodSet(U).Len() == 0 {
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continue // empty interface
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}
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// T concrete, U interface
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if types.AssignableTo(T, U) {
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from = append(from, U)
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} else if pT := types.NewPointer(T); types.AssignableTo(pT, U) {
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fromPtr = append(fromPtr, U)
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}
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}
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}
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var pos interface{} = qpos
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if nt, ok := deref(T).(*types.Named); ok {
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pos = nt.Obj()
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}
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// Sort types (arbitrarily) to ensure test determinism.
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sort.Sort(typesByString(to))
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sort.Sort(typesByString(from))
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sort.Sort(typesByString(fromPtr))
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var toMethod, fromMethod, fromPtrMethod []*types.Selection // contain nils
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if method != nil {
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for _, t := range to {
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toMethod = append(toMethod,
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types.NewMethodSet(t).Lookup(method.Pkg(), method.Name()))
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}
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for _, t := range from {
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fromMethod = append(fromMethod,
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types.NewMethodSet(t).Lookup(method.Pkg(), method.Name()))
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}
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for _, t := range fromPtr {
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fromPtrMethod = append(fromPtrMethod,
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types.NewMethodSet(t).Lookup(method.Pkg(), method.Name()))
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}
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}
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q.result = &implementsResult{
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qpos, T, pos, to, from, fromPtr, method, toMethod, fromMethod, fromPtrMethod,
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}
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return nil
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}
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type implementsResult struct {
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qpos *queryPos
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t types.Type // queried type (not necessarily named)
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pos interface{} // pos of t (*types.Name or *QueryPos)
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to []types.Type // named or ptr-to-named types assignable to interface T
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from []types.Type // named interfaces assignable from T
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fromPtr []types.Type // named interfaces assignable only from *T
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// if a method was queried:
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method *types.Func // queried method
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toMethod []*types.Selection // method of type to[i], if any
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fromMethod []*types.Selection // method of type from[i], if any
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fromPtrMethod []*types.Selection // method of type fromPtrMethod[i], if any
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}
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func (r *implementsResult) display(printf printfFunc) {
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relation := "is implemented by"
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meth := func(sel *types.Selection) {
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if sel != nil {
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printf(sel.Obj(), "\t%s method (%s).%s",
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relation, r.qpos.typeString(sel.Recv()), sel.Obj().Name())
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}
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}
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if isInterface(r.t) {
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if types.NewMethodSet(r.t).Len() == 0 { // TODO(adonovan): cache mset
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printf(r.pos, "empty interface type %s", r.qpos.typeString(r.t))
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return
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}
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if r.method == nil {
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printf(r.pos, "interface type %s", r.qpos.typeString(r.t))
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} else {
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printf(r.method, "abstract method %s", r.qpos.objectString(r.method))
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}
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// Show concrete types (or methods) first; use two passes.
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for i, sub := range r.to {
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if !isInterface(sub) {
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if r.method == nil {
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printf(deref(sub).(*types.Named).Obj(), "\t%s %s type %s",
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relation, typeKind(sub), r.qpos.typeString(sub))
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} else {
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meth(r.toMethod[i])
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}
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}
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}
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for i, sub := range r.to {
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if isInterface(sub) {
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if r.method == nil {
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printf(sub.(*types.Named).Obj(), "\t%s %s type %s",
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relation, typeKind(sub), r.qpos.typeString(sub))
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} else {
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meth(r.toMethod[i])
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}
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}
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}
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relation = "implements"
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for i, super := range r.from {
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if r.method == nil {
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printf(super.(*types.Named).Obj(), "\t%s %s",
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relation, r.qpos.typeString(super))
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} else {
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meth(r.fromMethod[i])
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}
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}
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} else {
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relation = "implements"
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if r.from != nil {
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if r.method == nil {
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printf(r.pos, "%s type %s",
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typeKind(r.t), r.qpos.typeString(r.t))
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} else {
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printf(r.method, "concrete method %s",
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r.qpos.objectString(r.method))
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}
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for i, super := range r.from {
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if r.method == nil {
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printf(super.(*types.Named).Obj(), "\t%s %s",
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relation, r.qpos.typeString(super))
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} else {
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meth(r.fromMethod[i])
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}
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}
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}
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if r.fromPtr != nil {
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if r.method == nil {
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printf(r.pos, "pointer type *%s", r.qpos.typeString(r.t))
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} else {
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// TODO(adonovan): de-dup (C).f and (*C).f implementing (I).f.
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printf(r.method, "concrete method %s",
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r.qpos.objectString(r.method))
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}
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for i, psuper := range r.fromPtr {
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if r.method == nil {
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printf(psuper.(*types.Named).Obj(), "\t%s %s",
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relation, r.qpos.typeString(psuper))
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} else {
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meth(r.fromPtrMethod[i])
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}
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}
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} else if r.from == nil {
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printf(r.pos, "%s type %s implements only interface{}",
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typeKind(r.t), r.qpos.typeString(r.t))
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}
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}
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}
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func (r *implementsResult) toSerial(res *serial.Result, fset *token.FileSet) {
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res.Implements = &serial.Implements{
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T: makeImplementsType(r.t, fset),
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AssignableTo: makeImplementsTypes(r.to, fset),
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AssignableFrom: makeImplementsTypes(r.from, fset),
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AssignableFromPtr: makeImplementsTypes(r.fromPtr, fset),
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AssignableToMethod: methodsToSerial(r.qpos.info.Pkg, r.toMethod, fset),
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AssignableFromMethod: methodsToSerial(r.qpos.info.Pkg, r.fromMethod, fset),
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AssignableFromPtrMethod: methodsToSerial(r.qpos.info.Pkg, r.fromPtrMethod, fset),
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}
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if r.method != nil {
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res.Implements.Method = &serial.DescribeMethod{
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Name: r.qpos.objectString(r.method),
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Pos: fset.Position(r.method.Pos()).String(),
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}
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}
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}
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func makeImplementsTypes(tt []types.Type, fset *token.FileSet) []serial.ImplementsType {
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var r []serial.ImplementsType
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for _, t := range tt {
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r = append(r, makeImplementsType(t, fset))
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}
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return r
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}
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func makeImplementsType(T types.Type, fset *token.FileSet) serial.ImplementsType {
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var pos token.Pos
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if nt, ok := deref(T).(*types.Named); ok { // implementsResult.t may be non-named
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pos = nt.Obj().Pos()
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}
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return serial.ImplementsType{
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Name: T.String(),
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Pos: fset.Position(pos).String(),
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Kind: typeKind(T),
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}
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}
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// typeKind returns a string describing the underlying kind of type,
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// e.g. "slice", "array", "struct".
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func typeKind(T types.Type) string {
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s := reflect.TypeOf(T.Underlying()).String()
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return strings.ToLower(strings.TrimPrefix(s, "*types."))
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}
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func isInterface(T types.Type) bool { return types.IsInterface(T) }
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type typesByString []types.Type
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func (p typesByString) Len() int { return len(p) }
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func (p typesByString) Less(i, j int) bool { return p[i].String() < p[j].String() }
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func (p typesByString) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
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