golang callee 代码
文件路径：/src/cmd/vendor/golang.org/x/tools/go/types/typeutil/callee.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 typeutil
import (
"go/ast"
"go/types"
"golang.org/x/tools/go/ast/astutil"
"golang.org/x/tools/internal/typeparams"
)
/ Callee returns the named target of a function call, if any:
/ a function, method, builtin, or variable.
/
/ Functions and methods may potentially have type parameters.
func Callee(info *types.Info, call *ast.CallExpr) types.Object {
fun := astutil.Unparen(call.Fun)
/ Look through type instantiation if necessary.
isInstance := false
switch fun.(type) {
case *ast.IndexExpr, *typeparams.IndexListExpr:
/ When extracting the callee from an *IndexExpr, we need to check that
/ it is a *types.Func and not a *types.Var.
/ Example: Don't match a slice m within the expression `m[0]()`.
isInstance = true
fun, _, _, _ = typeparams.UnpackIndexExpr(fun)
}
var obj types.Object
switch fun := fun.(type) {
case *ast.Ident:
obj = info.Uses[fun] / type, var, builtin, or declared func
case *ast.SelectorExpr:
if sel, ok := info.Selections[fun]; ok {
obj = sel.Obj() / method or field
} else {
obj = info.Uses[fun.Sel] / qualified identifier?
}
}
if _, ok := obj.(*types.TypeName); ok {
return nil / T(x) is a conversion, not a call
}
/ A Func is required to match instantiations.
if _, ok := obj.(*types.Func); isInstance && !ok {
return nil / Was not a Func.
}
return obj
}
/ StaticCallee returns the target (function or method) of a static function
/ call, if any. It returns nil for calls to builtins.
/
/ Note: for calls of instantiated functions and methods, StaticCallee returns
/ the corresponding generic function or method on the generic type.
func StaticCallee(info *types.Info, call *ast.CallExpr) *types.Func {
if f, ok := Callee(info, call).(*types.Func); ok && !interfaceMethod(f) {
return f
}
return nil
}
func interfaceMethod(f *types.Func) bool {
recv := f.Type().(*types.Signature).Recv()
return recv != nil && types.IsInterface(recv.Type())
}