/
moq.go
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/
moq.go
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package moq
import (
"bytes"
"errors"
"go/token"
"go/types"
"io"
"strings"
"github.com/matryer/moq/internal/registry"
"github.com/matryer/moq/internal/template"
)
// Mocker can generate mock structs.
type Mocker struct {
cfg Config
registry *registry.Registry
tmpl template.Template
}
// Config specifies details about how interfaces should be mocked.
// SrcDir is the only field which needs be specified.
type Config struct {
SrcDir string
PkgName string
Formatter string
StubImpl bool
SkipEnsure bool
WithResets bool
}
// New makes a new Mocker for the specified package directory.
func New(cfg Config) (*Mocker, error) {
reg, err := registry.New(cfg.SrcDir, cfg.PkgName)
if err != nil {
return nil, err
}
tmpl, err := template.New()
if err != nil {
return nil, err
}
return &Mocker{
cfg: cfg,
registry: reg,
tmpl: tmpl,
}, nil
}
// Mock generates a mock for the specified interface name.
func (m *Mocker) Mock(w io.Writer, namePairs ...string) error {
if len(namePairs) == 0 {
return errors.New("must specify one interface")
}
mocks := make([]template.MockData, len(namePairs))
for i, np := range namePairs {
name, mockName := parseInterfaceName(np)
iface, tparams, err := m.registry.LookupInterface(name)
if err != nil {
return err
}
methods := make([]template.MethodData, iface.NumMethods())
for j := 0; j < iface.NumMethods(); j++ {
methods[j] = m.methodData(iface.Method(j))
}
mocks[i] = template.MockData{
InterfaceName: name,
MockName: mockName,
Methods: methods,
TypeParams: m.typeParams(tparams),
}
}
data := template.Data{
PkgName: m.mockPkgName(),
Mocks: mocks,
StubImpl: m.cfg.StubImpl,
SkipEnsure: m.cfg.SkipEnsure,
WithResets: m.cfg.WithResets,
}
if data.MocksSomeMethod() {
m.registry.AddImport(types.NewPackage("sync", "sync"))
}
if m.registry.SrcPkgName() != m.mockPkgName() {
data.SrcPkgQualifier = m.registry.SrcPkgName() + "."
if !m.cfg.SkipEnsure {
imprt := m.registry.AddImport(m.registry.SrcPkg())
data.SrcPkgQualifier = imprt.Qualifier() + "."
}
}
data.Imports = m.registry.Imports()
var buf bytes.Buffer
if err := m.tmpl.Execute(&buf, data); err != nil {
return err
}
formatted, err := m.format(buf.Bytes())
if err != nil {
return err
}
if _, err := w.Write(formatted); err != nil {
return err
}
return nil
}
func (m *Mocker) typeParams(tparams *types.TypeParamList) []template.TypeParamData {
var tpd []template.TypeParamData
if tparams == nil {
return tpd
}
tpd = make([]template.TypeParamData, tparams.Len())
scope := m.registry.MethodScope()
for i := 0; i < len(tpd); i++ {
tp := tparams.At(i)
typeParam := types.NewParam(token.Pos(i), tp.Obj().Pkg(), tp.Obj().Name(), tp.Constraint())
tpd[i] = template.TypeParamData{
ParamData: template.ParamData{Var: scope.AddVar(typeParam, "")},
Constraint: explicitConstraintType(typeParam),
}
}
return tpd
}
func explicitConstraintType(typeParam *types.Var) (t types.Type) {
underlying := typeParam.Type().Underlying().(*types.Interface)
// check if any of the embedded types is either a basic type or a union,
// because the generic type has to be an alias for one of those types then
for j := 0; j < underlying.NumEmbeddeds(); j++ {
t := underlying.EmbeddedType(j)
switch t := t.(type) {
case *types.Basic:
return t
case *types.Union: // only unions of basic types are allowed, so just take the first one as a valid type constraint
return t.Term(0).Type()
}
}
return nil
}
func (m *Mocker) methodData(f *types.Func) template.MethodData {
sig := f.Type().(*types.Signature)
scope := m.registry.MethodScope()
n := sig.Params().Len()
params := make([]template.ParamData, n)
for i := 0; i < n; i++ {
p := template.ParamData{
Var: scope.AddVar(sig.Params().At(i), ""),
}
p.Variadic = sig.Variadic() && i == n-1 && p.Var.IsSlice() // check for final variadic argument
params[i] = p
}
n = sig.Results().Len()
results := make([]template.ParamData, n)
for i := 0; i < n; i++ {
results[i] = template.ParamData{
Var: scope.AddVar(sig.Results().At(i), "Out"),
}
}
return template.MethodData{
Name: f.Name(),
Params: params,
Returns: results,
}
}
func (m *Mocker) mockPkgName() string {
if m.cfg.PkgName != "" {
return m.cfg.PkgName
}
return m.registry.SrcPkgName()
}
func (m *Mocker) format(src []byte) ([]byte, error) {
switch m.cfg.Formatter {
case "goimports":
return goimports(src)
case "noop":
return src, nil
}
return gofmt(src)
}
func parseInterfaceName(namePair string) (ifaceName, mockName string) {
parts := strings.SplitN(namePair, ":", 2)
if len(parts) == 2 {
return parts[0], parts[1]
}
ifaceName = parts[0]
return ifaceName, ifaceName + "Mock"
}