"go/ast"
"go/token"
"os"
+ "strconv"
)
type fix struct {
fixes = append(fixes, f)
}
-// rewrite walks the AST x, calling visit(y) for each node y in the tree but
-// also with a pointer to each ast.Expr, in a bottom-up traversal.
-func rewrite(x interface{}, visit func(interface{})) {
- switch n := x.(type) {
- case *ast.Expr:
- rewrite(*n, visit)
+// walk traverses the AST x, calling visit(y) for each node y in the tree but
+// also with a pointer to each ast.Expr, ast.Stmt, and *ast.BlockStmt,
+// in a bottom-up traversal.
+func walk(x interface{}, visit func(interface{})) {
+ walkBeforeAfter(x, nop, visit)
+}
+
+func nop(interface{}) {}
- // everything else just recurses
+// walkBeforeAfter is like walk but calls before(x) before traversing
+// x's children and after(x) afterward.
+func walkBeforeAfter(x interface{}, before, after func(interface{})) {
+ before(x)
+
+ switch n := x.(type) {
default:
- panic(fmt.Errorf("unexpected type %T in walk", x))
+ panic(fmt.Errorf("unexpected type %T in walkBeforeAfter", x))
case nil:
+ // pointers to interfaces
+ case *ast.Decl:
+ walkBeforeAfter(*n, before, after)
+ case *ast.Expr:
+ walkBeforeAfter(*n, before, after)
+ case *ast.Spec:
+ walkBeforeAfter(*n, before, after)
+ case *ast.Stmt:
+ walkBeforeAfter(*n, before, after)
+
+ // pointers to struct pointers
+ case **ast.BlockStmt:
+ walkBeforeAfter(*n, before, after)
+ case **ast.CallExpr:
+ walkBeforeAfter(*n, before, after)
+ case **ast.FieldList:
+ walkBeforeAfter(*n, before, after)
+ case **ast.FuncType:
+ walkBeforeAfter(*n, before, after)
+
+ // pointers to slices
+ case *[]ast.Stmt:
+ walkBeforeAfter(*n, before, after)
+ case *[]ast.Expr:
+ walkBeforeAfter(*n, before, after)
+ case *[]ast.Decl:
+ walkBeforeAfter(*n, before, after)
+ case *[]ast.Spec:
+ walkBeforeAfter(*n, before, after)
+ case *[]*ast.File:
+ walkBeforeAfter(*n, before, after)
+
// These are ordered and grouped to match ../../pkg/go/ast/ast.go
case *ast.Field:
- rewrite(&n.Type, visit)
+ walkBeforeAfter(&n.Type, before, after)
case *ast.FieldList:
for _, field := range n.List {
- rewrite(field, visit)
+ walkBeforeAfter(field, before, after)
}
case *ast.BadExpr:
case *ast.Ident:
case *ast.Ellipsis:
case *ast.BasicLit:
case *ast.FuncLit:
- rewrite(n.Type, visit)
- rewrite(n.Body, visit)
+ walkBeforeAfter(&n.Type, before, after)
+ walkBeforeAfter(&n.Body, before, after)
case *ast.CompositeLit:
- rewrite(&n.Type, visit)
- rewrite(n.Elts, visit)
+ walkBeforeAfter(&n.Type, before, after)
+ walkBeforeAfter(&n.Elts, before, after)
case *ast.ParenExpr:
- rewrite(&n.X, visit)
+ walkBeforeAfter(&n.X, before, after)
case *ast.SelectorExpr:
- rewrite(&n.X, visit)
+ walkBeforeAfter(&n.X, before, after)
case *ast.IndexExpr:
- rewrite(&n.X, visit)
- rewrite(&n.Index, visit)
+ walkBeforeAfter(&n.X, before, after)
+ walkBeforeAfter(&n.Index, before, after)
case *ast.SliceExpr:
- rewrite(&n.X, visit)
+ walkBeforeAfter(&n.X, before, after)
if n.Low != nil {
- rewrite(&n.Low, visit)
+ walkBeforeAfter(&n.Low, before, after)
}
if n.High != nil {
- rewrite(&n.High, visit)
+ walkBeforeAfter(&n.High, before, after)
}
case *ast.TypeAssertExpr:
- rewrite(&n.X, visit)
- rewrite(&n.Type, visit)
+ walkBeforeAfter(&n.X, before, after)
+ walkBeforeAfter(&n.Type, before, after)
case *ast.CallExpr:
- rewrite(&n.Fun, visit)
- rewrite(n.Args, visit)
+ walkBeforeAfter(&n.Fun, before, after)
+ walkBeforeAfter(&n.Args, before, after)
case *ast.StarExpr:
- rewrite(&n.X, visit)
+ walkBeforeAfter(&n.X, before, after)
case *ast.UnaryExpr:
- rewrite(&n.X, visit)
+ walkBeforeAfter(&n.X, before, after)
case *ast.BinaryExpr:
- rewrite(&n.X, visit)
- rewrite(&n.Y, visit)
+ walkBeforeAfter(&n.X, before, after)
+ walkBeforeAfter(&n.Y, before, after)
case *ast.KeyValueExpr:
- rewrite(&n.Key, visit)
- rewrite(&n.Value, visit)
+ walkBeforeAfter(&n.Key, before, after)
+ walkBeforeAfter(&n.Value, before, after)
case *ast.ArrayType:
- rewrite(&n.Len, visit)
- rewrite(&n.Elt, visit)
+ walkBeforeAfter(&n.Len, before, after)
+ walkBeforeAfter(&n.Elt, before, after)
case *ast.StructType:
- rewrite(n.Fields, visit)
+ walkBeforeAfter(&n.Fields, before, after)
case *ast.FuncType:
- rewrite(n.Params, visit)
+ walkBeforeAfter(&n.Params, before, after)
if n.Results != nil {
- rewrite(n.Results, visit)
+ walkBeforeAfter(&n.Results, before, after)
}
case *ast.InterfaceType:
- rewrite(n.Methods, visit)
+ walkBeforeAfter(&n.Methods, before, after)
case *ast.MapType:
- rewrite(&n.Key, visit)
- rewrite(&n.Value, visit)
+ walkBeforeAfter(&n.Key, before, after)
+ walkBeforeAfter(&n.Value, before, after)
case *ast.ChanType:
- rewrite(&n.Value, visit)
+ walkBeforeAfter(&n.Value, before, after)
case *ast.BadStmt:
case *ast.DeclStmt:
- rewrite(n.Decl, visit)
+ walkBeforeAfter(&n.Decl, before, after)
case *ast.EmptyStmt:
case *ast.LabeledStmt:
- rewrite(n.Stmt, visit)
+ walkBeforeAfter(&n.Stmt, before, after)
case *ast.ExprStmt:
- rewrite(&n.X, visit)
+ walkBeforeAfter(&n.X, before, after)
case *ast.SendStmt:
- rewrite(&n.Chan, visit)
- rewrite(&n.Value, visit)
+ walkBeforeAfter(&n.Chan, before, after)
+ walkBeforeAfter(&n.Value, before, after)
case *ast.IncDecStmt:
- rewrite(&n.X, visit)
+ walkBeforeAfter(&n.X, before, after)
case *ast.AssignStmt:
- rewrite(n.Lhs, visit)
- if len(n.Lhs) == 2 && len(n.Rhs) == 1 {
- rewrite(n.Rhs, visit)
- } else {
- rewrite(n.Rhs, visit)
- }
+ walkBeforeAfter(&n.Lhs, before, after)
+ walkBeforeAfter(&n.Rhs, before, after)
case *ast.GoStmt:
- rewrite(n.Call, visit)
+ walkBeforeAfter(&n.Call, before, after)
case *ast.DeferStmt:
- rewrite(n.Call, visit)
+ walkBeforeAfter(&n.Call, before, after)
case *ast.ReturnStmt:
- rewrite(n.Results, visit)
+ walkBeforeAfter(&n.Results, before, after)
case *ast.BranchStmt:
case *ast.BlockStmt:
- rewrite(n.List, visit)
+ walkBeforeAfter(&n.List, before, after)
case *ast.IfStmt:
- rewrite(n.Init, visit)
- rewrite(&n.Cond, visit)
- rewrite(n.Body, visit)
- rewrite(n.Else, visit)
+ walkBeforeAfter(&n.Init, before, after)
+ walkBeforeAfter(&n.Cond, before, after)
+ walkBeforeAfter(&n.Body, before, after)
+ walkBeforeAfter(&n.Else, before, after)
case *ast.CaseClause:
- rewrite(n.List, visit)
- rewrite(n.Body, visit)
+ walkBeforeAfter(&n.List, before, after)
+ walkBeforeAfter(&n.Body, before, after)
case *ast.SwitchStmt:
- rewrite(n.Init, visit)
- rewrite(&n.Tag, visit)
- rewrite(n.Body, visit)
+ walkBeforeAfter(&n.Init, before, after)
+ walkBeforeAfter(&n.Tag, before, after)
+ walkBeforeAfter(&n.Body, before, after)
case *ast.TypeSwitchStmt:
- rewrite(n.Init, visit)
- rewrite(n.Assign, visit)
- rewrite(n.Body, visit)
+ walkBeforeAfter(&n.Init, before, after)
+ walkBeforeAfter(&n.Assign, before, after)
+ walkBeforeAfter(&n.Body, before, after)
case *ast.CommClause:
- rewrite(n.Comm, visit)
- rewrite(n.Body, visit)
+ walkBeforeAfter(&n.Comm, before, after)
+ walkBeforeAfter(&n.Body, before, after)
case *ast.SelectStmt:
- rewrite(n.Body, visit)
+ walkBeforeAfter(&n.Body, before, after)
case *ast.ForStmt:
- rewrite(n.Init, visit)
- rewrite(&n.Cond, visit)
- rewrite(n.Post, visit)
- rewrite(n.Body, visit)
+ walkBeforeAfter(&n.Init, before, after)
+ walkBeforeAfter(&n.Cond, before, after)
+ walkBeforeAfter(&n.Post, before, after)
+ walkBeforeAfter(&n.Body, before, after)
case *ast.RangeStmt:
- rewrite(&n.Key, visit)
- rewrite(&n.Value, visit)
- rewrite(&n.X, visit)
- rewrite(n.Body, visit)
+ walkBeforeAfter(&n.Key, before, after)
+ walkBeforeAfter(&n.Value, before, after)
+ walkBeforeAfter(&n.X, before, after)
+ walkBeforeAfter(&n.Body, before, after)
case *ast.ImportSpec:
case *ast.ValueSpec:
- rewrite(&n.Type, visit)
- rewrite(n.Values, visit)
+ walkBeforeAfter(&n.Type, before, after)
+ walkBeforeAfter(&n.Values, before, after)
case *ast.TypeSpec:
- rewrite(&n.Type, visit)
+ walkBeforeAfter(&n.Type, before, after)
case *ast.BadDecl:
case *ast.GenDecl:
- rewrite(n.Specs, visit)
+ walkBeforeAfter(&n.Specs, before, after)
case *ast.FuncDecl:
if n.Recv != nil {
- rewrite(n.Recv, visit)
+ walkBeforeAfter(&n.Recv, before, after)
}
- rewrite(n.Type, visit)
+ walkBeforeAfter(&n.Type, before, after)
if n.Body != nil {
- rewrite(n.Body, visit)
+ walkBeforeAfter(&n.Body, before, after)
}
case *ast.File:
- rewrite(n.Decls, visit)
+ walkBeforeAfter(&n.Decls, before, after)
case *ast.Package:
- for _, file := range n.Files {
- rewrite(file, visit)
- }
+ walkBeforeAfter(&n.Files, before, after)
+ case []*ast.File:
+ for i := range n {
+ walkBeforeAfter(&n[i], before, after)
+ }
case []ast.Decl:
- for _, d := range n {
- rewrite(d, visit)
+ for i := range n {
+ walkBeforeAfter(&n[i], before, after)
}
case []ast.Expr:
for i := range n {
- rewrite(&n[i], visit)
+ walkBeforeAfter(&n[i], before, after)
}
case []ast.Stmt:
- for _, s := range n {
- rewrite(s, visit)
+ for i := range n {
+ walkBeforeAfter(&n[i], before, after)
}
case []ast.Spec:
- for _, s := range n {
- rewrite(s, visit)
+ for i := range n {
+ walkBeforeAfter(&n[i], before, after)
}
}
- visit(x)
+ after(x)
}
+// imports returns true if f imports path.
func imports(f *ast.File, path string) bool {
- for _, decl := range f.Decls {
- d, ok := decl.(*ast.GenDecl)
- if !ok {
- continue
- }
- for _, spec := range d.Specs {
- s, ok := spec.(*ast.ImportSpec)
- if !ok {
- continue
- }
- if string(s.Path.Value) == `"`+path+`"` {
- return true
- }
+ for _, s := range f.Imports {
+ t, err := strconv.Unquote(s.Path.Value)
+ if err == nil && t == path {
+ return true
}
}
return false
}
+// isPkgDot returns true if t is the expression "pkg.name"
+// where pkg is an imported identifier.
func isPkgDot(t ast.Expr, pkg, name string) bool {
sel, ok := t.(*ast.SelectorExpr)
- if !ok {
- return false
- }
- return isTopName(sel.X, pkg) && sel.Sel.String() == name
+ return ok && isTopName(sel.X, pkg) && sel.Sel.String() == name
}
+// isPtrPkgDot returns true if f is the expression "*pkg.name"
+// where pkg is an imported identifier.
func isPtrPkgDot(t ast.Expr, pkg, name string) bool {
ptr, ok := t.(*ast.StarExpr)
- if !ok {
- return false
- }
- return isPkgDot(ptr.X, pkg, name)
+ return ok && isPkgDot(ptr.X, pkg, name)
}
+// isTopName returns true if n is a top-level unresolved identifier with the given name.
func isTopName(n ast.Expr, name string) bool {
id, ok := n.(*ast.Ident)
- if !ok {
- return false
- }
- return id.Name == name && id.Obj == nil
+ return ok && id.Name == name && id.Obj == nil
}
+// isName returns true if n is an identifier with the given name.
func isName(n ast.Expr, name string) bool {
id, ok := n.(*ast.Ident)
- if !ok {
- return false
- }
- return id.String() == name
+ return ok && id.String() == name
}
+// isCall returns true if t is a call to pkg.name.
func isCall(t ast.Expr, pkg, name string) bool {
call, ok := t.(*ast.CallExpr)
return ok && isPkgDot(call.Fun, pkg, name)
}
+// If n is an *ast.Ident, isIdent returns it; otherwise isIdent returns nil.
+func isIdent(n interface{}) *ast.Ident {
+ id, _ := n.(*ast.Ident)
+ return id
+}
+
+// refersTo returns true if n is a reference to the same object as x.
func refersTo(n ast.Node, x *ast.Ident) bool {
id, ok := n.(*ast.Ident)
- if !ok {
- return false
- }
- return id.String() == x.String()
+ // The test of id.Name == x.Name handles top-level unresolved
+ // identifiers, which all have Obj == nil.
+ return ok && id.Obj == x.Obj && id.Name == x.Name
}
+// isBlank returns true if n is the blank identifier.
func isBlank(n ast.Expr) bool {
return isName(n, "_")
}
+// isEmptyString returns true if n is an empty string literal.
func isEmptyString(n ast.Expr) bool {
lit, ok := n.(*ast.BasicLit)
- if !ok {
- return false
- }
- if lit.Kind != token.STRING {
- return false
- }
- s := string(lit.Value)
- return s == `""` || s == "``"
+ return ok && lit.Kind == token.STRING && len(lit.Value) == 2
}
func warn(pos token.Pos, msg string, args ...interface{}) {
}
fmt.Fprintf(os.Stderr, msg+"\n", args...)
}
+
+// countUses returns the number of uses of the identifier x in scope.
+func countUses(x *ast.Ident, scope []ast.Stmt) int {
+ count := 0
+ ff := func(n interface{}) {
+ if n, ok := n.(ast.Node); ok && refersTo(n, x) {
+ count++
+ }
+ }
+ for _, n := range scope {
+ walk(n, ff)
+ }
+ return count
+}
+
+// rewriteUses replaces all uses of the identifier x and !x in scope
+// with f(x.Pos()) and fnot(x.Pos()).
+func rewriteUses(x *ast.Ident, f, fnot func(token.Pos) ast.Expr, scope []ast.Stmt) {
+ var lastF ast.Expr
+ ff := func(n interface{}) {
+ ptr, ok := n.(*ast.Expr)
+ if !ok {
+ return
+ }
+ nn := *ptr
+
+ // The child node was just walked and possibly replaced.
+ // If it was replaced and this is a negation, replace with fnot(p).
+ not, ok := nn.(*ast.UnaryExpr)
+ if ok && not.Op == token.NOT && not.X == lastF {
+ *ptr = fnot(nn.Pos())
+ return
+ }
+ if refersTo(nn, x) {
+ lastF = f(nn.Pos())
+ *ptr = lastF
+ }
+ }
+ for _, n := range scope {
+ walk(n, ff)
+ }
+}
+
+// assignsTo returns true if any of the code in scope assigns to or takes the address of x.
+func assignsTo(x *ast.Ident, scope []ast.Stmt) bool {
+ assigned := false
+ ff := func(n interface{}) {
+ if assigned {
+ return
+ }
+ switch n := n.(type) {
+ case *ast.UnaryExpr:
+ // use of &x
+ if n.Op == token.AND && refersTo(n.X, x) {
+ assigned = true
+ return
+ }
+ case *ast.AssignStmt:
+ for _, l := range n.Lhs {
+ if refersTo(l, x) {
+ assigned = true
+ return
+ }
+ }
+ }
+ }
+ for _, n := range scope {
+ if assigned {
+ break
+ }
+ walk(n, ff)
+ }
+ return assigned
+}
+
+// newPkgDot returns an ast.Expr referring to "pkg.name" at position pos.
+func newPkgDot(pos token.Pos, pkg, name string) ast.Expr {
+ return &ast.SelectorExpr{
+ X: &ast.Ident{
+ NamePos: pos,
+ Name: pkg,
+ },
+ Sel: &ast.Ident{
+ NamePos: pos,
+ Name: name,
+ },
+ }
+}
if !ok {
continue
}
- rewrite(fn.Body, func(n interface{}) {
+ walk(fn.Body, func(n interface{}) {
// Want to replace expression sometimes,
// so record pointer to it for updating below.
ptr, ok := n.(*ast.Expr)
import (
"bytes"
+ "exec"
"flag"
"fmt"
"go/parser"
var allowed map[string]bool
+var doDiff = flag.Bool("diff", false, "display diffs instead of rewriting files")
+
func usage() {
- fmt.Fprintf(os.Stderr, "usage: gofix [-r fixname,...] [path ...]\n")
+ fmt.Fprintf(os.Stderr, "usage: gofix [-diff] [-r fixname,...] [path ...]\n")
flag.PrintDefaults()
fmt.Fprintf(os.Stderr, "\nAvailable rewrites are:\n")
for _, f := range fixes {
printerMode = printer.TabIndent | printer.UseSpaces
)
+var printConfig = &printer.Config{
+ printerMode,
+ tabWidth,
+}
func processFile(filename string, useStdin bool) os.Error {
var f *os.File
var err os.Error
+ var fixlog bytes.Buffer
+ var buf bytes.Buffer
if useStdin {
f = os.Stdin
return err
}
+ // Apply all fixes to file.
+ newFile := file
fixed := false
- var buf bytes.Buffer
for _, fix := range fixes {
if allowed != nil && !allowed[fix.desc] {
continue
}
- if fix.f(file) {
+ if fix.f(newFile) {
fixed = true
- fmt.Fprintf(&buf, " %s", fix.name)
+ fmt.Fprintf(&fixlog, " %s", fix.name)
+
+ // AST changed.
+ // Print and parse, to update any missing scoping
+ // or position information for subsequent fixers.
+ buf.Reset()
+ _, err = printConfig.Fprint(&buf, fset, newFile)
+ if err != nil {
+ return err
+ }
+ newSrc := buf.Bytes()
+ newFile, err = parser.ParseFile(fset, filename, newSrc, parserMode)
+ if err != nil {
+ return err
+ }
}
}
if !fixed {
return nil
}
- fmt.Fprintf(os.Stderr, "%s: fixed %s\n", filename, buf.String()[1:])
+ fmt.Fprintf(os.Stderr, "%s: fixed %s\n", filename, fixlog.String()[1:])
+ // Print AST. We did that after each fix, so this appears
+ // redundant, but it is necessary to generate gofmt-compatible
+ // source code in a few cases. The official gofmt style is the
+ // output of the printer run on a standard AST generated by the parser,
+ // but the source we generated inside the loop above is the
+ // output of the printer run on a mangled AST generated by a fixer.
buf.Reset()
- _, err = (&printer.Config{printerMode, tabWidth}).Fprint(&buf, fset, file)
+ _, err = printConfig.Fprint(&buf, fset, newFile)
if err != nil {
return err
}
+ newSrc := buf.Bytes()
+
+ if *doDiff {
+ data, err := diff(src, newSrc)
+ if err != nil {
+ return fmt.Errorf("computing diff: %s", err)
+ }
+ fmt.Printf("diff %s fixed/%s\n", filename, filename)
+ os.Stdout.Write(data)
+ return nil
+ }
if useStdin {
- os.Stdout.Write(buf.Bytes())
+ os.Stdout.Write(newSrc)
return nil
}
- return ioutil.WriteFile(f.Name(), buf.Bytes(), 0)
+ return ioutil.WriteFile(f.Name(), newSrc, 0)
+}
+
+var gofmtBuf bytes.Buffer
+
+func gofmt(n interface{}) string {
+ gofmtBuf.Reset()
+ _, err := printConfig.Fprint(&gofmtBuf, fset, n)
+ if err != nil {
+ return "<" + err.String() + ">"
+ }
+ return gofmtBuf.String()
}
func report(err os.Error) {
// ignore non-Go files
return f.IsRegular() && !strings.HasPrefix(f.Name, ".") && strings.HasSuffix(f.Name, ".go")
}
+
+func diff(b1, b2 []byte) (data []byte, err os.Error) {
+ f1, err := ioutil.TempFile("", "gofix")
+ if err != nil {
+ return nil, err
+ }
+ defer os.Remove(f1.Name())
+ defer f1.Close()
+
+ f2, err := ioutil.TempFile("", "gofix")
+ if err != nil {
+ return nil, err
+ }
+ defer os.Remove(f2.Name())
+ defer f2.Close()
+
+ f1.Write(b1)
+ f2.Write(b2)
+
+ diffcmd, err := exec.LookPath("diff")
+ if err != nil {
+ return nil, err
+ }
+
+ c, err := exec.Run(diffcmd, []string{"diff", f1.Name(), f2.Name()}, nil, "",
+ exec.DevNull, exec.Pipe, exec.MergeWithStdout)
+ if err != nil {
+ return nil, err
+ }
+ defer c.Close()
+
+ return ioutil.ReadAll(c.Stdout)
+}
import (
"bytes"
- "exec"
"go/ast"
"go/parser"
"go/printer"
- "io/ioutil"
- "os"
+ "strings"
"testing"
)
testCases = append(testCases, t...)
}
+func fnop(*ast.File) bool { return false }
+
func parseFixPrint(t *testing.T, fn func(*ast.File) bool, desc, in string) (out string, fixed, ok bool) {
file, err := parser.ParseFile(fset, desc, in, parserMode)
if err != nil {
t.Errorf("%s: printing: %v", desc, err)
return
}
- if s := buf.String(); in != s {
+ if s := buf.String(); in != s && fn != fnop {
t.Errorf("%s: not gofmt-formatted.\n--- %s\n%s\n--- %s | gofmt\n%s",
desc, desc, in, desc, s)
tdiff(t, in, s)
continue
}
+ // reformat to get printing right
+ out, _, ok = parseFixPrint(t, fnop, tt.Name, out)
+ if !ok {
+ continue
+ }
+
if out != tt.Out {
- t.Errorf("%s: incorrect output.\n--- have\n%s\n--- want\n%s", tt.Name, out, tt.Out)
+ t.Errorf("%s: incorrect output.\n", tt.Name)
+ if !strings.HasPrefix(tt.Name, "testdata/") {
+ t.Errorf("--- have\n%s\n--- want\n%s", out, tt.Out)
+ }
tdiff(t, out, tt.Out)
continue
}
}
func tdiff(t *testing.T, a, b string) {
- f1, err := ioutil.TempFile("", "gofix")
- if err != nil {
- t.Error(err)
- return
- }
- defer os.Remove(f1.Name())
- defer f1.Close()
-
- f2, err := ioutil.TempFile("", "gofix")
- if err != nil {
- t.Error(err)
- return
- }
- defer os.Remove(f2.Name())
- defer f2.Close()
-
- f1.Write([]byte(a))
- f2.Write([]byte(b))
-
- diffcmd, err := exec.LookPath("diff")
- if err != nil {
- t.Error(err)
- return
- }
-
- c, err := exec.Run(diffcmd, []string{"diff", f1.Name(), f2.Name()}, nil, "",
- exec.DevNull, exec.Pipe, exec.MergeWithStdout)
+ data, err := diff([]byte(a), []byte(b))
if err != nil {
t.Error(err)
return
}
- defer c.Close()
-
- data, err := ioutil.ReadAll(c.Stdout)
- if err != nil {
- t.Error(err)
- return
- }
-
t.Error(string(data))
}
}
fixed := false
- rewrite(f, func(n interface{}) {
+ walk(f, func(n interface{}) {
call, ok := n.(*ast.CallExpr)
if !ok || !isPkgDot(call.Fun, "net", "Dial") || len(call.Args) != 3 {
return
}
fixed := false
- rewrite(f, func(n interface{}) {
+ walk(f, func(n interface{}) {
call, ok := n.(*ast.CallExpr)
if !ok || !isPkgDot(call.Fun, "tls", "Dial") || len(call.Args) != 4 {
return
}
fixed := false
- rewrite(f, func(n interface{}) {
+ walk(f, func(n interface{}) {
as, ok := n.(*ast.AssignStmt)
if !ok || len(as.Lhs) != 3 || len(as.Rhs) != 1 {
return
}
fixed := false
- rewrite(f, func(n interface{}) {
+ walk(f, func(n interface{}) {
// Rename O_CREAT to O_CREATE.
if expr, ok := n.(ast.Expr); ok && isPkgDot(expr, "os", "O_CREAT") {
expr.(*ast.SelectorExpr).Sel.Name = "O_CREATE"
}
fixed := false
- rewrite(f, func(n interface{}) {
+ walk(f, func(n interface{}) {
call, ok := n.(*ast.CallExpr)
if !ok || len(call.Args) != 5 {
return
--- /dev/null
+// Copyright 2011 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 main
+
+import (
+ "fmt"
+ "go/ast"
+ "go/token"
+ "os"
+ "reflect"
+ "strings"
+)
+
+// Partial type checker.
+//
+// The fact that it is partial is very important: the input is
+// an AST and a description of some type information to
+// assume about one or more packages, but not all the
+// packages that the program imports. The checker is
+// expected to do as much as it can with what it has been
+// given. There is not enough information supplied to do
+// a full type check, but the type checker is expected to
+// apply information that can be derived from variable
+// declarations, function and method returns, and type switches
+// as far as it can, so that the caller can still tell the types
+// of expression relevant to a particular fix.
+//
+// TODO(rsc,gri): Replace with go/typechecker.
+// Doing that could be an interesting test case for go/typechecker:
+// the constraints about working with partial information will
+// likely exercise it in interesting ways. The ideal interface would
+// be to pass typecheck a map from importpath to package API text
+// (Go source code), but for now we use data structures (TypeConfig, Type).
+//
+// The strings mostly use gofmt form.
+//
+// A Field or FieldList has as its type a comma-separated list
+// of the types of the fields. For example, the field list
+// x, y, z int
+// has type "int, int, int".
+
+// The prefix "type " is the type of a type.
+// For example, given
+// var x int
+// type T int
+// x's type is "int" but T's type is "type int".
+// mkType inserts the "type " prefix.
+// getType removes it.
+// isType tests for it.
+
+func mkType(t string) string {
+ return "type " + t
+}
+
+func getType(t string) string {
+ if !isType(t) {
+ return ""
+ }
+ return t[len("type "):]
+}
+
+func isType(t string) bool {
+ return strings.HasPrefix(t, "type ")
+}
+
+// TypeConfig describes the universe of relevant types.
+// For ease of creation, the types are all referred to by string
+// name (e.g., "reflect.Value"). TypeByName is the only place
+// where the strings are resolved.
+
+type TypeConfig struct {
+ Type map[string]*Type
+ Var map[string]string
+ Func map[string]string
+}
+
+// typeof returns the type of the given name, which may be of
+// the form "x" or "p.X".
+func (cfg *TypeConfig) typeof(name string) string {
+ if cfg.Var != nil {
+ if t := cfg.Var[name]; t != "" {
+ return t
+ }
+ }
+ if cfg.Func != nil {
+ if t := cfg.Func[name]; t != "" {
+ return "func()" + t
+ }
+ }
+ return ""
+}
+
+// Type describes the Fields and Methods of a type.
+// If the field or method cannot be found there, it is next
+// looked for in the Embed list.
+type Type struct {
+ Field map[string]string // map field name to type
+ Method map[string]string // map method name to comma-separated return types
+ Embed []string // list of types this type embeds (for extra methods)
+}
+
+// dot returns the type of "typ.name", making its decision
+// using the type information in cfg.
+func (typ *Type) dot(cfg *TypeConfig, name string) string {
+ if typ.Field != nil {
+ if t := typ.Field[name]; t != "" {
+ return t
+ }
+ }
+ if typ.Method != nil {
+ if t := typ.Method[name]; t != "" {
+ return t
+ }
+ }
+
+ for _, e := range typ.Embed {
+ etyp := cfg.Type[e]
+ if etyp != nil {
+ if t := etyp.dot(cfg, name); t != "" {
+ return t
+ }
+ }
+ }
+
+ return ""
+}
+
+// typecheck type checks the AST f assuming the information in cfg.
+// It returns a map from AST nodes to type information in gofmt string form.
+func typecheck(cfg *TypeConfig, f *ast.File) map[interface{}]string {
+ typeof := make(map[interface{}]string)
+
+ // gather function declarations
+ for _, decl := range f.Decls {
+ fn, ok := decl.(*ast.FuncDecl)
+ if !ok {
+ continue
+ }
+ typecheck1(cfg, fn.Type, typeof)
+ t := typeof[fn.Type]
+ if fn.Recv != nil {
+ // The receiver must be a type.
+ rcvr := typeof[fn.Recv]
+ if !isType(rcvr) {
+ if len(fn.Recv.List) != 1 {
+ continue
+ }
+ rcvr = mkType(gofmt(fn.Recv.List[0].Type))
+ typeof[fn.Recv.List[0].Type] = rcvr
+ }
+ rcvr = getType(rcvr)
+ if rcvr != "" && rcvr[0] == '*' {
+ rcvr = rcvr[1:]
+ }
+ typeof[rcvr+"."+fn.Name.Name] = t
+ } else {
+ if isType(t) {
+ t = getType(t)
+ } else {
+ t = gofmt(fn.Type)
+ }
+ typeof[fn.Name] = t
+
+ // Record typeof[fn.Name.Obj] for future references to fn.Name.
+ typeof[fn.Name.Obj] = t
+ }
+ }
+
+ typecheck1(cfg, f, typeof)
+ return typeof
+}
+
+func makeExprList(a []*ast.Ident) []ast.Expr {
+ var b []ast.Expr
+ for _, x := range a {
+ b = append(b, x)
+ }
+ return b
+}
+
+// Typecheck1 is the recursive form of typecheck.
+// It is like typecheck but adds to the information in typeof
+// instead of allocating a new map.
+func typecheck1(cfg *TypeConfig, f interface{}, typeof map[interface{}]string) {
+ // set sets the type of n to typ.
+ // If isDecl is true, n is being declared.
+ set := func(n ast.Expr, typ string, isDecl bool) {
+ if typeof[n] != "" || typ == "" {
+ return
+ }
+ typeof[n] = typ
+
+ // If we obtained typ from the declaration of x
+ // propagate the type to all the uses.
+ // The !isDecl case is a cheat here, but it makes
+ // up in some cases for not paying attention to
+ // struct fields. The real type checker will be
+ // more accurate so we won't need the cheat.
+ if id, ok := n.(*ast.Ident); ok && id.Obj != nil && (isDecl || typeof[id.Obj] == "") {
+ typeof[id.Obj] = typ
+ }
+ }
+
+ // Type-check an assignment lhs = rhs.
+ // If isDecl is true, this is := so we can update
+ // the types of the objects that lhs refers to.
+ typecheckAssign := func(lhs, rhs []ast.Expr, isDecl bool) {
+ if len(lhs) > 1 && len(rhs) == 1 {
+ if _, ok := rhs[0].(*ast.CallExpr); ok {
+ t := split(typeof[rhs[0]])
+ // Lists should have same length but may not; pair what can be paired.
+ for i := 0; i < len(lhs) && i < len(t); i++ {
+ set(lhs[i], t[i], isDecl)
+ }
+ return
+ }
+ }
+ if len(lhs) == 1 && len(rhs) == 2 {
+ // x = y, ok
+ rhs = rhs[:1]
+ } else if len(lhs) == 2 && len(rhs) == 1 {
+ // x, ok = y
+ lhs = lhs[:1]
+ }
+
+ // Match as much as we can.
+ for i := 0; i < len(lhs) && i < len(rhs); i++ {
+ x, y := lhs[i], rhs[i]
+ if typeof[y] != "" {
+ set(x, typeof[y], isDecl)
+ } else {
+ set(y, typeof[x], false)
+ }
+ }
+ }
+
+ // The main type check is a recursive algorithm implemented
+ // by walkBeforeAfter(n, before, after).
+ // Most of it is bottom-up, but in a few places we need
+ // to know the type of the function we are checking.
+ // The before function records that information on
+ // the curfn stack.
+ var curfn []*ast.FuncType
+
+ before := func(n interface{}) {
+ // push function type on stack
+ switch n := n.(type) {
+ case *ast.FuncDecl:
+ curfn = append(curfn, n.Type)
+ case *ast.FuncLit:
+ curfn = append(curfn, n.Type)
+ }
+ }
+
+ // After is the real type checker.
+ after := func(n interface{}) {
+ if n == nil {
+ return
+ }
+ if false && reflect.Typeof(n).Kind() == reflect.Ptr { // debugging trace
+ defer func() {
+ if t := typeof[n]; t != "" {
+ pos := fset.Position(n.(ast.Node).Pos())
+ fmt.Fprintf(os.Stderr, "%s: typeof[%s] = %s\n", pos.String(), gofmt(n), t)
+ }
+ }()
+ }
+
+ switch n := n.(type) {
+ case *ast.FuncDecl, *ast.FuncLit:
+ // pop function type off stack
+ curfn = curfn[:len(curfn)-1]
+
+ case *ast.FuncType:
+ typeof[n] = mkType(joinFunc(split(typeof[n.Params]), split(typeof[n.Results])))
+
+ case *ast.FieldList:
+ // Field list is concatenation of sub-lists.
+ t := ""
+ for _, field := range n.List {
+ if t != "" {
+ t += ", "
+ }
+ t += typeof[field]
+ }
+ typeof[n] = t
+
+ case *ast.Field:
+ // Field is one instance of the type per name.
+ all := ""
+ t := typeof[n.Type]
+ if !isType(t) {
+ // Create a type, because it is typically *T or *p.T
+ // and we might care about that type.
+ t = mkType(gofmt(n.Type))
+ typeof[n.Type] = t
+ }
+ t = getType(t)
+ if len(n.Names) == 0 {
+ all = t
+ } else {
+ for _, id := range n.Names {
+ if all != "" {
+ all += ", "
+ }
+ all += t
+ typeof[id.Obj] = t
+ typeof[id] = t
+ }
+ }
+ typeof[n] = all
+
+ case *ast.ValueSpec:
+ // var declaration. Use type if present.
+ if n.Type != nil {
+ t := typeof[n.Type]
+ if !isType(t) {
+ t = mkType(gofmt(n.Type))
+ typeof[n.Type] = t
+ }
+ t = getType(t)
+ for _, id := range n.Names {
+ set(id, t, true)
+ }
+ }
+ // Now treat same as assignment.
+ typecheckAssign(makeExprList(n.Names), n.Values, true)
+
+ case *ast.AssignStmt:
+ typecheckAssign(n.Lhs, n.Rhs, n.Tok == token.DEFINE)
+
+ case *ast.Ident:
+ // Identifier can take its type from underlying object.
+ if t := typeof[n.Obj]; t != "" {
+ typeof[n] = t
+ }
+
+ case *ast.SelectorExpr:
+ // Field or method.
+ name := n.Sel.Name
+ if t := typeof[n.X]; t != "" {
+ if strings.HasPrefix(t, "*") {
+ t = t[1:] // implicit *
+ }
+ if typ := cfg.Type[t]; typ != nil {
+ if t := typ.dot(cfg, name); t != "" {
+ typeof[n] = t
+ return
+ }
+ }
+ tt := typeof[t+"."+name]
+ if isType(tt) {
+ typeof[n] = getType(tt)
+ return
+ }
+ }
+ // Package selector.
+ if x, ok := n.X.(*ast.Ident); ok && x.Obj == nil {
+ str := x.Name + "." + name
+ if cfg.Type[str] != nil {
+ typeof[n] = mkType(str)
+ return
+ }
+ if t := cfg.typeof(x.Name + "." + name); t != "" {
+ typeof[n] = t
+ return
+ }
+ }
+
+ case *ast.CallExpr:
+ // make(T) has type T.
+ if isTopName(n.Fun, "make") && len(n.Args) >= 1 {
+ typeof[n] = gofmt(n.Args[0])
+ return
+ }
+ // Otherwise, use type of function to determine arguments.
+ t := typeof[n.Fun]
+ in, out := splitFunc(t)
+ if in == nil && out == nil {
+ return
+ }
+ typeof[n] = join(out)
+ for i, arg := range n.Args {
+ if i >= len(in) {
+ break
+ }
+ if typeof[arg] == "" {
+ typeof[arg] = in[i]
+ }
+ }
+
+ case *ast.TypeAssertExpr:
+ // x.(type) has type of x.
+ if n.Type == nil {
+ typeof[n] = typeof[n.X]
+ return
+ }
+ // x.(T) has type T.
+ if t := typeof[n.Type]; isType(t) {
+ typeof[n] = getType(t)
+ }
+
+ case *ast.SliceExpr:
+ // x[i:j] has type of x.
+ typeof[n] = typeof[n.X]
+
+ case *ast.IndexExpr:
+ // x[i] has key type of x's type.
+ t := typeof[n.X]
+ if strings.HasPrefix(t, "[") || strings.HasPrefix(t, "map[") {
+ // Lazy: assume there are no nested [] in the array
+ // length or map key type.
+ if i := strings.Index(t, "]"); i >= 0 {
+ typeof[n] = t[i+1:]
+ }
+ }
+
+ case *ast.StarExpr:
+ // *x for x of type *T has type T when x is an expr.
+ // We don't use the result when *x is a type, but
+ // compute it anyway.
+ t := typeof[n.X]
+ if isType(t) {
+ typeof[n] = "type *" + getType(t)
+ } else if strings.HasPrefix(t, "*") {
+ typeof[n] = t[len("*"):]
+ }
+
+ case *ast.UnaryExpr:
+ // &x for x of type T has type *T.
+ t := typeof[n.X]
+ if t != "" && n.Op == token.AND {
+ typeof[n] = "&" + t
+ }
+
+ case *ast.CompositeLit:
+ // T{...} has type T.
+ typeof[n] = gofmt(n.Type)
+
+ case *ast.ParenExpr:
+ // (x) has type of x.
+ typeof[n] = typeof[n.X]
+
+ case *ast.TypeSwitchStmt:
+ // Type of variable changes for each case in type switch,
+ // but go/parser generates just one variable.
+ // Repeat type check for each case with more precise
+ // type information.
+ as, ok := n.Assign.(*ast.AssignStmt)
+ if !ok {
+ return
+ }
+ varx, ok := as.Lhs[0].(*ast.Ident)
+ if !ok {
+ return
+ }
+ t := typeof[varx]
+ for _, cas := range n.Body.List {
+ cas := cas.(*ast.CaseClause)
+ if len(cas.List) == 1 {
+ // Variable has specific type only when there is
+ // exactly one type in the case list.
+ if tt := typeof[cas.List[0]]; isType(tt) {
+ tt = getType(tt)
+ typeof[varx] = tt
+ typeof[varx.Obj] = tt
+ typecheck1(cfg, cas.Body, typeof)
+ }
+ }
+ }
+ // Restore t.
+ typeof[varx] = t
+ typeof[varx.Obj] = t
+
+ case *ast.ReturnStmt:
+ if len(curfn) == 0 {
+ // Probably can't happen.
+ return
+ }
+ f := curfn[len(curfn)-1]
+ res := n.Results
+ if f.Results != nil {
+ t := split(typeof[f.Results])
+ for i := 0; i < len(res) && i < len(t); i++ {
+ set(res[i], t[i], false)
+ }
+ }
+ }
+ }
+ walkBeforeAfter(f, before, after)
+}
+
+// Convert between function type strings and lists of types.
+// Using strings makes this a little harder, but it makes
+// a lot of the rest of the code easier. This will all go away
+// when we can use go/typechecker directly.
+
+// splitFunc splits "func(x,y,z) (a,b,c)" into ["x", "y", "z"] and ["a", "b", "c"].
+func splitFunc(s string) (in, out []string) {
+ if !strings.HasPrefix(s, "func(") {
+ return nil, nil
+ }
+
+ i := len("func(") // index of beginning of 'in' arguments
+ nparen := 0
+ for j := i; j < len(s); j++ {
+ switch s[j] {
+ case '(':
+ nparen++
+ case ')':
+ nparen--
+ if nparen < 0 {
+ // found end of parameter list
+ out := strings.TrimSpace(s[j+1:])
+ if len(out) >= 2 && out[0] == '(' && out[len(out)-1] == ')' {
+ out = out[1 : len(out)-1]
+ }
+ return split(s[i:j]), split(out)
+ }
+ }
+ }
+ return nil, nil
+}
+
+// joinFunc is the inverse of splitFunc.
+func joinFunc(in, out []string) string {
+ outs := ""
+ if len(out) == 1 {
+ outs = " " + out[0]
+ } else if len(out) > 1 {
+ outs = " (" + join(out) + ")"
+ }
+ return "func(" + join(in) + ")" + outs
+}
+
+// split splits "int, float" into ["int", "float"] and splits "" into [].
+func split(s string) []string {
+ out := []string{}
+ i := 0 // current type being scanned is s[i:j].
+ nparen := 0
+ for j := 0; j < len(s); j++ {
+ switch s[j] {
+ case ' ':
+ if i == j {
+ i++
+ }
+ case '(':
+ nparen++
+ case ')':
+ nparen--
+ if nparen < 0 {
+ // probably can't happen
+ return nil
+ }
+ case ',':
+ if nparen == 0 {
+ if i < j {
+ out = append(out, s[i:j])
+ }
+ i = j + 1
+ }
+ }
+ }
+ if nparen != 0 {
+ // probably can't happen
+ return nil
+ }
+ if i < len(s) {
+ out = append(out, s[i:])
+ }
+ return out
+}
+
+// join is the inverse of split.
+func join(x []string) string {
+ return strings.Join(x, ", ")
+}