Golang token.NewFileSet函数代码示例

// TestLineComments, using a simple test case, checks that consecutive line
// comments are properly terminated with a newline even if the AST position
// information is incorrect.
//
func TestLineComments(t *testing.T) {
	const src = `// comment 1
	// comment 2
	// comment 3
	package main
	`

	fset := token.NewFileSet()
	f, err := parser.ParseFile(fset, "", src, parser.ParseComments)
	if err != nil {
		panic(err) // error in test
	}

	var buf bytes.Buffer
	fset = token.NewFileSet() // use the wrong file set
	Fprint(&buf, fset, f)

	nlines := 0
	for _, ch := range buf.Bytes() {
		if ch == '\n' {
			nlines++
		}
	}

	const expected = 3
	if nlines < expected {
		t.Errorf("got %d, expected %d\n", nlines, expected)
		t.Errorf("result:\n%s", buf.Bytes())
	}
}

func TestLeadAndLineComments(t *testing.T) {
	f, err := ParseFile(token.NewFileSet(), "", `
package p
type T struct {
	/* F1 lead comment */
	//
	F1 int  /* F1 */ // line comment
	// F2 lead
	// comment
	F2 int  // F2 line comment
	// f3 lead comment
	f3 int  // f3 line comment
}
`, ParseComments)
	if err != nil {
		t.Fatal(err)
	}
	checkFieldComments(t, f, "T.F1", "/* F1 lead comment *///", "/* F1 */// line comment")
	checkFieldComments(t, f, "T.F2", "// F2 lead// comment", "// F2 line comment")
	checkFieldComments(t, f, "T.f3", "// f3 lead comment", "// f3 line comment")
	ast.FileExports(f)
	checkFieldComments(t, f, "T.F1", "/* F1 lead comment *///", "/* F1 */// line comment")
	checkFieldComments(t, f, "T.F2", "// F2 lead// comment", "// F2 line comment")
	if getField(f, "T.f3") != nil {
		t.Error("not expected to find T.f3")
	}
}

func TestUnresolved(t *testing.T) {
	f, err := ParseFile(token.NewFileSet(), "", `
package p
//
func f1a(int)
func f2a(byte, int, float)
func f3a(a, b int, c float)
func f4a(...complex)
func f5a(a s1a, b ...complex)
//
func f1b(*int)
func f2b([]byte, (int), *float)
func f3b(a, b *int, c []float)
func f4b(...*complex)
func f5b(a s1a, b ...[]complex)
//
type s1a struct { int }
type s2a struct { byte; int; s1a }
type s3a struct { a, b int; c float }
//
type s1b struct { *int }
type s2b struct { byte; int; *float }
type s3b struct { a, b *s3b; c []float }
`, 0)
	if err != nil {
		t.Fatal(err)
	}

	want := "int " + // f1a
		"byte int float " + // f2a
		"int float " + // f3a
		"complex " + // f4a
		"complex " + // f5a
		//
		"int " + // f1b
		"byte int float " + // f2b
		"int float " + // f3b
		"complex " + // f4b
		"complex " + // f5b
		//
		"int " + // s1a
		"byte int " + // s2a
		"int float " + // s3a
		//
		"int " + // s1a
		"byte int float " + // s2a
		"float " // s3a

	// collect unresolved identifiers
	var buf bytes.Buffer
	for _, u := range f.Unresolved {
		buf.WriteString(u.Name)
		buf.WriteByte(' ')
	}
	got := buf.String()

	if got != want {
		t.Errorf("\ngot:  %s\nwant: %s", got, want)
	}
}

func ExampleScanner_Scan() {
	// src is the input that we want to tokenize.
	src := []byte("cos(x) + 1i*sin(x) // Euler")

	// Initialize the scanner.
	var s scanner.Scanner
	fset := token.NewFileSet()                      // positions are relative to fset
	file := fset.AddFile("", fset.Base(), len(src)) // register input "file"
	s.Init(file, src, nil /* no error handler */, scanner.ScanComments)

	// Repeated calls to Scan yield the token sequence found in the input.
	for {
		pos, tok, lit := s.Scan()
		if tok == token.EOF {
			break
		}
		fmt.Printf("%s\t%s\t%q\n", fset.Position(pos), tok, lit)
	}

	// output:
	// 1:1	IDENT	"cos"
	// 1:4	(	""
	// 1:5	IDENT	"x"
	// 1:6	)	""
	// 1:8	+	""
	// 1:10	IMAG	"1i"
	// 1:12	*	""
	// 1:13	IDENT	"sin"
	// 1:16	(	""
	// 1:17	IDENT	"x"
	// 1:18	)	""
	// 1:20	;	"\n"
	// 1:20	COMMENT	"// Euler"
}

// TestIncompleteSelection ensures that an incomplete selector
// expression is parsed as a (blank) *ast.SelectorExpr, not a
// *ast.BadExpr.
func TestIncompleteSelection(t *testing.T) {
	for _, src := range []string{
		"package p; var _ = fmt.",             // at EOF
		"package p; var _ = fmt.\ntype X int", // not at EOF
	} {
		fset := token.NewFileSet()
		f, err := ParseFile(fset, "", src, 0)
		if err == nil {
			t.Errorf("ParseFile(%s) succeeded unexpectedly", src)
			continue
		}

		const wantErr = "expected selector or type assertion"
		if !strings.Contains(err.Error(), wantErr) {
			t.Errorf("ParseFile returned wrong error %q, want %q", err, wantErr)
		}

		var sel *ast.SelectorExpr
		ast.Inspect(f, func(n ast.Node) bool {
			if n, ok := n.(*ast.SelectorExpr); ok {
				sel = n
			}
			return true
		})
		if sel == nil {
			t.Error("found no *ast.SelectorExpr")
			continue
		}
		const wantSel = "&{fmt _}"
		if fmt.Sprint(sel) != wantSel {
			t.Errorf("found selector %s, want %s", sel, wantSel)
			continue
		}
	}
}

func TestParse(t *testing.T) {
	for _, filename := range validFiles {
		_, err := ParseFile(token.NewFileSet(), filename, nil, DeclarationErrors)
		if err != nil {
			t.Fatalf("ParseFile(%s): %v", filename, err)
		}
	}
}

func BenchmarkParse(b *testing.B) {
	b.SetBytes(int64(len(src)))
	for i := 0; i < b.N; i++ {
		if _, err := ParseFile(token.NewFileSet(), "", src, ParseComments); err != nil {
			b.Fatalf("benchmark failed due to parse error: %s", err)
		}
	}
}

func TestImports(t *testing.T) {
	for path, isValid := range imports {
		src := fmt.Sprintf("package p; import %s", path)
		_, err := ParseFile(token.NewFileSet(), "", src, 0)
		switch {
		case err != nil && isValid:
			t.Errorf("ParseFile(%s): got %v; expected no error", src, err)
		case err == nil && !isValid:
			t.Errorf("ParseFile(%s): got no error; expected one", src)
		}
	}
}

func parseFunc(filename, functionname string) (fun *ast.FuncDecl, fset *token.FileSet) {
	fset = token.NewFileSet()
	if file, err := parser.ParseFile(fset, filename, nil, 0); err == nil {
		for _, d := range file.Decls {
			if f, ok := d.(*ast.FuncDecl); ok && f.Name.Name == functionname {
				fun = f
				return
			}
		}
	}
	panic("function not found")
}

func main() {
	flag.Parse()
	fset := token.NewFileSet()
	nheadings := 0
	err := filepath.Walk(*root, func(path string, fi os.FileInfo, err error) error {
		if !fi.IsDir() {
			return nil
		}
		pkgs, err := parser.ParseDir(fset, path, isGoFile, parser.ParseComments)
		if err != nil {
			if *verbose {
				fmt.Fprintln(os.Stderr, err)
			}
			return nil
		}
		for _, pkg := range pkgs {
			d := doc.New(pkg, path, doc.Mode(0))
			list := appendHeadings(nil, d.Doc)
			for _, d := range d.Consts {
				list = appendHeadings(list, d.Doc)
			}
			for _, d := range d.Types {
				list = appendHeadings(list, d.Doc)
			}
			for _, d := range d.Vars {
				list = appendHeadings(list, d.Doc)
			}
			for _, d := range d.Funcs {
				list = appendHeadings(list, d.Doc)
			}
			if len(list) > 0 {
				// directories may contain multiple packages;
				// print path and package name
				fmt.Printf("%s (package %s)\n", path, pkg.Name)
				for _, h := range list {
					fmt.Printf("\t%s\n", h)
				}
				nheadings += len(list)
			}
		}
		return nil
	})
	if err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
	fmt.Println(nheadings, "headings found")
}

func RewriteTypesWithProtobufStructTags(name string, structTags map[string]map[string]string) error {
	fset := token.NewFileSet()
	src, err := ioutil.ReadFile(name)
	if err != nil {
		return err
	}
	file, err := parser.ParseFile(fset, name, src, parser.DeclarationErrors|parser.ParseComments)
	if err != nil {
		return err
	}

	allErrs := []error{}

	// set any new struct tags
	for _, d := range file.Decls {
		if errs := updateStructTags(d, structTags, []string{"protobuf"}); len(errs) > 0 {
			allErrs = append(allErrs, errs...)
		}
	}

	if len(allErrs) > 0 {
		var s string
		for _, err := range allErrs {
			s += err.Error() + "\n"
		}
		return errors.New(s)
	}

	b := &bytes.Buffer{}
	if err := printer.Fprint(b, fset, file); err != nil {
		return err
	}

	body, err := format.Source(b.Bytes())
	if err != nil {
		return fmt.Errorf("%s\n---\nunable to format %q: %v", b, name, err)
	}

	f, err := os.OpenFile(name, os.O_WRONLY|os.O_TRUNC, 0644)
	if err != nil {
		return err
	}
	defer f.Close()
	if _, err := f.Write(body); err != nil {
		return err
	}
	return f.Close()
}

func BenchmarkScan(b *testing.B) {
	b.StopTimer()
	fset := token.NewFileSet()
	file := fset.AddFile("", fset.Base(), len(source))
	var s Scanner
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		s.Init(file, source, nil, ScanComments)
		for {
			_, tok, _ := s.Scan()
			if tok == token.EOF {
				break
			}
		}
	}
}

func TestCommentGroups(t *testing.T) {
	f, err := ParseFile(token.NewFileSet(), "", `
package p /* 1a */ /* 1b */      /* 1c */ // 1d
/* 2a
*/
// 2b
const pi = 3.1415
/* 3a */ // 3b
/* 3c */ const e = 2.7182

// Example from issue 3139
func ExampleCount() {
	fmt.Println(strings.Count("cheese", "e"))
	fmt.Println(strings.Count("five", "")) // before & after each rune
	// Output:
	// 3
	// 5
}
`, ParseComments)
	if err != nil {
		t.Fatal(err)
	}
	expected := [][]string{
		{"/* 1a */", "/* 1b */", "/* 1c */", "// 1d"},
		{"/* 2a\n*/", "// 2b"},
		{"/* 3a */", "// 3b", "/* 3c */"},
		{"// Example from issue 3139"},
		{"// before & after each rune"},
		{"// Output:", "// 3", "// 5"},
	}
	if len(f.Comments) != len(expected) {
		t.Fatalf("got %d comment groups; expected %d", len(f.Comments), len(expected))
	}
	for i, exp := range expected {
		got := f.Comments[i].List
		if len(got) != len(exp) {
			t.Errorf("got %d comments in group %d; expected %d", len(got), i, len(exp))
			continue
		}
		for j, exp := range exp {
			got := got[j].Text
			if got != exp {
				t.Errorf("got %q in group %d; expected %q", got, i, exp)
			}
		}
	}
}

func TestObjects(t *testing.T) {
	const src = `
package p
import fmt "fmt"
const pi = 3.14
type T struct{}
var x int
func f() { L: }
`

	f, err := ParseFile(token.NewFileSet(), "", src, 0)
	if err != nil {
		t.Fatal(err)
	}

	objects := map[string]ast.ObjKind{
		"p":   ast.Bad, // not in a scope
		"fmt": ast.Bad, // not resolved yet
		"pi":  ast.Con,
		"T":   ast.Typ,
		"x":   ast.Var,
		"int": ast.Bad, // not resolved yet
		"f":   ast.Fun,
		"L":   ast.Lbl,
	}

	ast.Inspect(f, func(n ast.Node) bool {
		if ident, ok := n.(*ast.Ident); ok {
			obj := ident.Obj
			if obj == nil {
				if objects[ident.Name] != ast.Bad {
					t.Errorf("no object for %s", ident.Name)
				}
				return true
			}
			if obj.Name != ident.Name {
				t.Errorf("names don't match: obj.Name = %s, ident.Name = %s", obj.Name, ident.Name)
			}
			kind := objects[ident.Name]
			if obj.Kind != kind {
				t.Errorf("%s: obj.Kind = %s; want %s", ident.Name, obj.Kind, kind)
			}
		}
		return true
	})
}

// TestIssue9979 verifies that empty statements are contained within their enclosing blocks.
func TestIssue9979(t *testing.T) {
	for _, src := range []string{
		"package p; func f() {;}",
		"package p; func f() {L:}",
		"package p; func f() {L:;}",
		"package p; func f() {L:\n}",
		"package p; func f() {L:\n;}",
		"package p; func f() { ; }",
		"package p; func f() { L: }",
		"package p; func f() { L: ; }",
		"package p; func f() { L: \n}",
		"package p; func f() { L: \n; }",
	} {
		fset := token.NewFileSet()
		f, err := ParseFile(fset, "", src, 0)
		if err != nil {
			t.Fatal(err)
		}

		var pos, end token.Pos
		ast.Inspect(f, func(x ast.Node) bool {
			switch s := x.(type) {
			case *ast.BlockStmt:
				pos, end = s.Pos()+1, s.End()-1 // exclude "{", "}"
			case *ast.LabeledStmt:
				pos, end = s.Pos()+2, s.End() // exclude "L:"
			case *ast.EmptyStmt:
				// check containment
				if s.Pos() < pos || s.End() > end {
					t.Errorf("%s: %T[%d, %d] not inside [%d, %d]", src, s, s.Pos(), s.End(), pos, end)
				}
				// check semicolon
				offs := fset.Position(s.Pos()).Offset
				if ch := src[offs]; ch != ';' != s.Implicit {
					want := "want ';'"
					if s.Implicit {
						want = "but ';' is implicit"
					}
					t.Errorf("%s: found %q at offset %d; %s", src, ch, offs, want)
				}
			}
			return true
		})
	}
}