Golang Signature.Results方法代码示例

func hasError(sig *types.Signature) bool {
	res := sig.Results()
	if res == nil || res.Len() <= 0 {
		return false
	}

	nerr := 0
	for i := 0; i < res.Len(); i++ {
		ret := res.At(i)
		if isErrorType(ret.Type()) {
			nerr++
		}
	}

	switch {
	case nerr == 0:
		return false
	case nerr == 1:
		return true
	default:
		panic(fmt.Errorf(
			"gopy: invalid number of comma-errors (%d)",
			nerr,
		))
	}

	return false
}

func (p *exporter) signature(sig *types.Signature) {
	// We need the receiver information (T vs *T)
	// for methods associated with named types.
	// We do not record interface receiver types in the
	// export data because 1) the importer can derive them
	// from the interface type and 2) they create cycles
	// in the type graph.
	if recv := sig.Recv(); recv != nil {
		if _, ok := recv.Type().Underlying().(*types.Interface); !ok {
			// 1-element tuple
			p.int(1)
			p.param(recv)
		} else {
			// 0-element tuple
			p.int(0)
		}
	} else {
		// 0-element tuple
		p.int(0)
	}
	p.tuple(sig.Params())
	p.tuple(sig.Results())
	if sig.Variadic() {
		p.int(1)
	} else {
		p.int(0)
	}
}

func (d *DIBuilder) descriptorSignature(t *types.Signature, name string) llvm.Value {
	// If there's a receiver change the receiver to an
	// additional (first) parameter, and take the value of
	// the resulting signature instead.
	if recv := t.Recv(); recv != nil {
		params := t.Params()
		paramvars := make([]*types.Var, int(params.Len()+1))
		paramvars[0] = recv
		for i := 0; i < int(params.Len()); i++ {
			paramvars[i+1] = params.At(i)
		}
		params = types.NewTuple(paramvars...)
		t := types.NewSignature(nil, nil, params, t.Results(), t.Variadic())
		return d.typeDebugDescriptor(t, name)
	}
	if dt, ok := d.types.At(t).(llvm.Value); ok {
		return dt
	}

	var returnType llvm.Value
	results := t.Results()
	switch n := results.Len(); n {
	case 0:
		returnType = d.DIType(nil) // void
	case 1:
		returnType = d.DIType(results.At(0).Type())
	default:
		fields := make([]*types.Var, results.Len())
		for i := range fields {
			f := results.At(i)
			// Structs may not have multiple fields
			// with the same name, excepting "_".
			if f.Name() == "" {
				f = types.NewVar(f.Pos(), f.Pkg(), "_", f.Type())
			}
			fields[i] = f
		}
		returnType = d.typeDebugDescriptor(types.NewStruct(fields, nil), "")
	}

	var paramTypes []llvm.Value
	params := t.Params()
	if params != nil && params.Len() > 0 {
		paramTypes = make([]llvm.Value, params.Len()+1)
		paramTypes[0] = returnType
		for i := range paramTypes[1:] {
			paramTypes[i+1] = d.DIType(params.At(i).Type())
		}
	} else {
		paramTypes = []llvm.Value{returnType}
	}

	// TODO(axw) get position of type definition for File field
	return d.builder.CreateSubroutineType(llvm.DISubroutineType{
		Parameters: paramTypes,
	})
}

func newSignatureFrom(pkg *Package, sig *types.Signature) *Signature {
	var recv *Var
	if sig.Recv() != nil {
		recv = newVarFrom(pkg, sig.Recv())
	}

	return &Signature{
		ret:  newVarsFrom(pkg, sig.Results()),
		args: newVarsFrom(pkg, sig.Params()),
		recv: recv,
	}
}

func (c *funcContext) translateCall(e *ast.CallExpr, sig *types.Signature, fun *expression) *expression {
	args := c.translateArgs(sig, e.Args, e.Ellipsis.IsValid(), false)
	if c.Blocking[e] {
		resumeCase := c.caseCounter
		c.caseCounter++
		returnVar := "$r"
		if sig.Results().Len() != 0 {
			returnVar = c.newVariable("_r")
		}
		c.Printf("%[1]s = %[2]s(%[3]s); /* */ $s = %[4]d; case %[4]d: if($c) { $c = false; %[1]s = %[1]s.$blk(); } if (%[1]s && %[1]s.$blk !== undefined) { break s; }", returnVar, fun, strings.Join(args, ", "), resumeCase)
		if sig.Results().Len() != 0 {
			return c.formatExpr("%s", returnVar)
		}
		return c.formatExpr("")
	}
	return c.formatExpr("%s(%s)", fun, strings.Join(args, ", "))
}

func newFuncFrom(p *Package, parent string, obj types.Object, sig *types.Signature) (Func, error) {
	haserr := false
	res := sig.Results()
	var ret types.Type

	switch res.Len() {
	case 2:
		if !isErrorType(res.At(1).Type()) {
			return Func{}, fmt.Errorf(
				"bind: second result value must be of type error: %s",
				obj,
			)
		}
		haserr = true
		ret = res.At(0).Type()

	case 1:
		if isErrorType(res.At(0).Type()) {
			haserr = true
			ret = nil
		} else {
			ret = res.At(0).Type()
		}
	case 0:
		ret = nil
	default:
		return Func{}, fmt.Errorf("bind: too many results to return: %v", obj)
	}

	id := obj.Pkg().Name() + "_" + obj.Name()
	if parent != "" {
		id = obj.Pkg().Name() + "_" + parent + "_" + obj.Name()
	}

	return Func{
		pkg:  p,
		sig:  newSignatureFrom(p, sig),
		typ:  obj.Type(),
		name: obj.Name(),
		id:   id,
		doc:  p.getDoc(parent, obj),
		ret:  ret,
		err:  haserr,
	}, nil
}

func (tm *llvmTypeMap) getSignatureInfo(sig *types.Signature) functionTypeInfo {
	var args, results []types.Type
	if sig.Recv() != nil {
		recvtype := sig.Recv().Type()
		if _, ok := recvtype.Underlying().(*types.Pointer); !ok && recvtype != types.Typ[types.UnsafePointer] {
			recvtype = types.NewPointer(recvtype)
		}
		args = []types.Type{recvtype}
	}

	for i := 0; i != sig.Params().Len(); i++ {
		args = append(args, sig.Params().At(i).Type())
	}
	for i := 0; i != sig.Results().Len(); i++ {
		results = append(results, sig.Results().At(i).Type())
	}
	return tm.getFunctionTypeInfo(args, results)
}

func (p *printer) writeSignatureInternal(this *types.Package, sig *types.Signature, visited []types.Type) {
	p.writeTuple(this, sig.Params(), sig.Variadic(), visited)

	res := sig.Results()
	n := res.Len()
	if n == 0 {
		// no result
		return
	}

	p.print(" ")
	if n == 1 && res.At(0).Name() == "" {
		// single unnamed result
		p.writeTypeInternal(this, res.At(0).Type(), visited)
		return
	}

	// multiple or named result(s)
	p.writeTuple(this, res, false, visited)
}

func parseMethodType(t *types.Signature) (ptype, rtype types.Type, err error) {
	mp := t.Params()
	if mp.Len() != 1 && mp.Len() != 2 {
		return nil, nil, errgo.New("wrong argument count")
	}
	ptype0 := mp.At(mp.Len() - 1).Type()
	ptype1, ok := ptype0.(*types.Pointer)
	if !ok {
		return nil, nil, errgo.New("parameter is not a pointer")
	}
	ptype = ptype1.Elem()
	if _, ok := ptype.Underlying().(*types.Struct); !ok {
		return nil, nil, errgo.Newf("parameter is %s, not a pointer to struct", ptype1.Elem())
	}
	rp := t.Results()
	if rp.Len() > 2 {
		return nil, nil, errgo.New("wrong result count")
	}
	if rp.Len() == 2 {
		rtype = rp.At(0).Type()
	}
	return ptype, rtype, nil
}

func (c *funcContext) translateBuiltin(name string, sig *types.Signature, args []ast.Expr, ellipsis bool) *expression {
	switch name {
	case "new":
		t := sig.Results().At(0).Type().(*types.Pointer)
		if c.p.Pkg.Path() == "syscall" && types.Identical(t.Elem().Underlying(), types.Typ[types.Uintptr]) {
			return c.formatExpr("new Uint8Array(8)")
		}
		switch t.Elem().Underlying().(type) {
		case *types.Struct, *types.Array:
			return c.formatExpr("%e", c.zeroValue(t.Elem()))
		default:
			return c.formatExpr("$newDataPointer(%e, %s)", c.zeroValue(t.Elem()), c.typeName(t))
		}
	case "make":
		switch argType := c.p.TypeOf(args[0]).Underlying().(type) {
		case *types.Slice:
			t := c.typeName(c.p.TypeOf(args[0]))
			if len(args) == 3 {
				return c.formatExpr("$makeSlice(%s, %f, %f)", t, args[1], args[2])
			}
			return c.formatExpr("$makeSlice(%s, %f)", t, args[1])
		case *types.Map:
			return c.formatExpr("{}")
		case *types.Chan:
			length := "0"
			if len(args) == 2 {
				length = c.translateExpr(args[1]).String()
			}
			return c.formatExpr("new %s(%s)", c.typeName(c.p.TypeOf(args[0])), length)
		default:
			panic(fmt.Sprintf("Unhandled make type: %T\n", argType))
		}
	case "len":
		switch argType := c.p.TypeOf(args[0]).Underlying().(type) {
		case *types.Basic:
			return c.formatExpr("%e.length", args[0])
		case *types.Slice:
			return c.formatExpr("%e.$length", args[0])
		case *types.Pointer:
			return c.formatExpr("(%e, %d)", args[0], argType.Elem().(*types.Array).Len())
		case *types.Map:
			return c.formatExpr("$keys(%e).length", args[0])
		case *types.Chan:
			return c.formatExpr("%e.$buffer.length", args[0])
		// length of array is constant
		default:
			panic(fmt.Sprintf("Unhandled len type: %T\n", argType))
		}
	case "cap":
		switch argType := c.p.TypeOf(args[0]).Underlying().(type) {
		case *types.Slice, *types.Chan:
			return c.formatExpr("%e.$capacity", args[0])
		case *types.Pointer:
			return c.formatExpr("(%e, %d)", args[0], argType.Elem().(*types.Array).Len())
		// capacity of array is constant
		default:
			panic(fmt.Sprintf("Unhandled cap type: %T\n", argType))
		}
	case "panic":
		return c.formatExpr("$panic(%s)", c.translateImplicitConversion(args[0], types.NewInterface(nil, nil)))
	case "append":
		if ellipsis || len(args) == 1 {
			argStr := c.translateArgs(sig, args, ellipsis, false)
			return c.formatExpr("$appendSlice(%s, %s)", argStr[0], argStr[1])
		}
		sliceType := sig.Results().At(0).Type().Underlying().(*types.Slice)
		return c.formatExpr("$append(%e, %s)", args[0], strings.Join(c.translateExprSlice(args[1:], sliceType.Elem()), ", "))
	case "delete":
		keyType := c.p.TypeOf(args[0]).Underlying().(*types.Map).Key()
		return c.formatExpr(`delete %e[%s.keyFor(%s)]`, args[0], c.typeName(keyType), c.translateImplicitConversion(args[1], keyType))
	case "copy":
		if basic, isBasic := c.p.TypeOf(args[1]).Underlying().(*types.Basic); isBasic && isString(basic) {
			return c.formatExpr("$copyString(%e, %e)", args[0], args[1])
		}
		return c.formatExpr("$copySlice(%e, %e)", args[0], args[1])
	case "print", "println":
		return c.formatExpr("console.log(%s)", strings.Join(c.translateExprSlice(args, nil), ", "))
	case "complex":
		argStr := c.translateArgs(sig, args, ellipsis, false)
		return c.formatExpr("new %s(%s, %s)", c.typeName(sig.Results().At(0).Type()), argStr[0], argStr[1])
	case "real":
		return c.formatExpr("%e.$real", args[0])
	case "imag":
		return c.formatExpr("%e.$imag", args[0])
	case "recover":
		return c.formatExpr("$recover()")
	case "close":
		return c.formatExpr(`$close(%e)`, args[0])
	default:
		panic(fmt.Sprintf("Unhandled builtin: %s\n", name))
	}
}

func changeRecv(s *types.Signature, recv *types.Var) *types.Signature {
	return types.NewSignature(recv, s.Params(), s.Results(), s.Variadic())
}