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|
package lint
import (
"go/ast"
"go/token"
"go/types"
"sync"
"golang.org/x/tools/go/gcexportdata"
)
// Package represents a package in the project.
type Package struct {
fset *token.FileSet
files map[string]*File
TypesPkg *types.Package
TypesInfo *types.Info
// sortable is the set of types in the package that implement sort.Interface.
Sortable map[string]bool
// main is whether this is a "main" package.
main int
mu sync.Mutex
}
var newImporter = func(fset *token.FileSet) types.ImporterFrom {
return gcexportdata.NewImporter(fset, make(map[string]*types.Package))
}
var (
trueValue = 1
falseValue = 2
notSet = 3
)
// IsMain returns if that's the main package.
func (p *Package) IsMain() bool {
if p.main == trueValue {
return true
} else if p.main == falseValue {
return false
}
for _, f := range p.files {
if f.isMain() {
p.main = trueValue
return true
}
}
p.main = falseValue
return false
}
// TypeCheck performs type checking for given package.
func (p *Package) TypeCheck() error {
p.mu.Lock()
// If type checking has already been performed
// skip it.
if p.TypesInfo != nil || p.TypesPkg != nil {
p.mu.Unlock()
return nil
}
config := &types.Config{
// By setting a no-op error reporter, the type checker does as much work as possible.
Error: func(error) {},
Importer: newImporter(p.fset),
}
info := &types.Info{
Types: make(map[ast.Expr]types.TypeAndValue),
Defs: make(map[*ast.Ident]types.Object),
Uses: make(map[*ast.Ident]types.Object),
Scopes: make(map[ast.Node]*types.Scope),
}
var anyFile *File
var astFiles []*ast.File
for _, f := range p.files {
anyFile = f
astFiles = append(astFiles, f.AST)
}
typesPkg, err := check(config, anyFile.AST.Name.Name, p.fset, astFiles, info)
// Remember the typechecking info, even if config.Check failed,
// since we will get partial information.
p.TypesPkg = typesPkg
p.TypesInfo = info
p.mu.Unlock()
return err
}
// check function encapsulates the call to go/types.Config.Check method and
// recovers if the called method panics (see issue #59)
func check(config *types.Config, n string, fset *token.FileSet, astFiles []*ast.File, info *types.Info) (p *types.Package, err error) {
defer func() {
if r := recover(); r != nil {
err, _ = r.(error)
p = nil
return
}
}()
return config.Check(n, fset, astFiles, info)
}
// TypeOf returns the type of an expression.
func (p *Package) TypeOf(expr ast.Expr) types.Type {
if p.TypesInfo == nil {
return nil
}
return p.TypesInfo.TypeOf(expr)
}
type walker struct {
nmap map[string]int
has map[string]int
}
func (w *walker) Visit(n ast.Node) ast.Visitor {
fn, ok := n.(*ast.FuncDecl)
if !ok || fn.Recv == nil || len(fn.Recv.List) == 0 {
return w
}
// TODO(dsymonds): We could check the signature to be more precise.
recv := receiverType(fn)
if i, ok := w.nmap[fn.Name.Name]; ok {
w.has[recv] |= i
}
return w
}
func (p *Package) scanSortable() {
p.Sortable = make(map[string]bool)
// bitfield for which methods exist on each type.
const (
Len = 1 << iota
Less
Swap
)
nmap := map[string]int{"Len": Len, "Less": Less, "Swap": Swap}
has := make(map[string]int)
for _, f := range p.files {
ast.Walk(&walker{nmap, has}, f.AST)
}
for typ, ms := range has {
if ms == Len|Less|Swap {
p.Sortable[typ] = true
}
}
}
// receiverType returns the named type of the method receiver, sans "*",
// or "invalid-type" if fn.Recv is ill formed.
func receiverType(fn *ast.FuncDecl) string {
switch e := fn.Recv.List[0].Type.(type) {
case *ast.Ident:
return e.Name
case *ast.StarExpr:
if id, ok := e.X.(*ast.Ident); ok {
return id.Name
}
}
// The parser accepts much more than just the legal forms.
return "invalid-type"
}
func (p *Package) lint(rules []Rule, config Config, failures chan Failure) {
p.scanSortable()
var wg sync.WaitGroup
for _, file := range p.files {
wg.Add(1)
go (func(file *File) {
file.lint(rules, config, failures)
defer wg.Done()
})(file)
}
wg.Wait()
}
|
