| // Copyright 2018 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 expect |
| |
| import ( |
| "fmt" |
| "go/ast" |
| "go/parser" |
| "go/token" |
| "path/filepath" |
| "regexp" |
| "strconv" |
| "strings" |
| "text/scanner" |
| |
| "golang.org/x/mod/modfile" |
| ) |
| |
| const commentStart = "@" |
| const commentStartLen = len(commentStart) |
| |
| // Identifier is the type for an identifier in an Note argument list. |
| type Identifier string |
| |
| // Parse collects all the notes present in a file. |
| // If content is nil, the filename specified is read and parsed, otherwise the |
| // content is used and the filename is used for positions and error messages. |
| // Each comment whose text starts with @ is parsed as a comma-separated |
| // sequence of notes. |
| // See the package documentation for details about the syntax of those |
| // notes. |
| func Parse(fset *token.FileSet, filename string, content []byte) ([]*Note, error) { |
| var src interface{} |
| if content != nil { |
| src = content |
| } |
| switch filepath.Ext(filename) { |
| case ".go": |
| // TODO: We should write this in terms of the scanner. |
| // there are ways you can break the parser such that it will not add all the |
| // comments to the ast, which may result in files where the tests are silently |
| // not run. |
| file, err := parser.ParseFile(fset, filename, src, parser.ParseComments|parser.AllErrors|parser.SkipObjectResolution) |
| if file == nil { |
| return nil, err |
| } |
| return ExtractGo(fset, file) |
| case ".mod": |
| file, err := modfile.Parse(filename, content, nil) |
| if err != nil { |
| return nil, err |
| } |
| f := fset.AddFile(filename, -1, len(content)) |
| f.SetLinesForContent(content) |
| notes, err := extractModWork(fset, file.Syntax.Stmt) |
| if err != nil { |
| return nil, err |
| } |
| // Since modfile.Parse does not return an *ast, we need to add the offset |
| // within the file's contents to the file's base relative to the fileset. |
| for _, note := range notes { |
| note.Pos += token.Pos(f.Base()) |
| } |
| return notes, nil |
| case ".work": |
| file, err := modfile.ParseWork(filename, content, nil) |
| if err != nil { |
| return nil, err |
| } |
| f := fset.AddFile(filename, -1, len(content)) |
| f.SetLinesForContent(content) |
| notes, err := extractModWork(fset, file.Syntax.Stmt) |
| if err != nil { |
| return nil, err |
| } |
| // As with go.mod files, we need to compute a synthetic token.Pos. |
| for _, note := range notes { |
| note.Pos += token.Pos(f.Base()) |
| } |
| return notes, nil |
| } |
| return nil, nil |
| } |
| |
| // extractModWork collects all the notes present in a go.mod file or go.work |
| // file, by way of the shared modfile.Expr statement node. |
| // |
| // Each comment whose text starts with @ is parsed as a comma-separated |
| // sequence of notes. |
| // See the package documentation for details about the syntax of those |
| // notes. |
| // Only allow notes to appear with the following format: "//@mark()" or // @mark() |
| func extractModWork(fset *token.FileSet, exprs []modfile.Expr) ([]*Note, error) { |
| var notes []*Note |
| for _, stmt := range exprs { |
| comment := stmt.Comment() |
| if comment == nil { |
| continue |
| } |
| var allComments []modfile.Comment |
| allComments = append(allComments, comment.Before...) |
| allComments = append(allComments, comment.Suffix...) |
| for _, cmt := range allComments { |
| text, adjust := getAdjustedNote(cmt.Token) |
| if text == "" { |
| continue |
| } |
| parsed, err := parse(fset, token.Pos(int(cmt.Start.Byte)+adjust), text) |
| if err != nil { |
| return nil, err |
| } |
| notes = append(notes, parsed...) |
| } |
| } |
| return notes, nil |
| } |
| |
| // ExtractGo collects all the notes present in an AST. |
| // Each comment whose text starts with @ is parsed as a comma-separated |
| // sequence of notes. |
| // See the package documentation for details about the syntax of those |
| // notes. |
| func ExtractGo(fset *token.FileSet, file *ast.File) ([]*Note, error) { |
| var notes []*Note |
| for _, g := range file.Comments { |
| for _, c := range g.List { |
| text, adjust := getAdjustedNote(c.Text) |
| if text == "" { |
| continue |
| } |
| parsed, err := parse(fset, token.Pos(int(c.Pos())+adjust), text) |
| if err != nil { |
| return nil, err |
| } |
| notes = append(notes, parsed...) |
| } |
| } |
| return notes, nil |
| } |
| |
| func getAdjustedNote(text string) (string, int) { |
| if strings.HasPrefix(text, "/*") { |
| text = strings.TrimSuffix(text, "*/") |
| } |
| text = text[2:] // remove "//" or "/*" prefix |
| |
| // Allow notes to appear within comments. |
| // For example: |
| // "// //@mark()" is valid. |
| // "// @mark()" is not valid. |
| // "// /*@mark()*/" is not valid. |
| var adjust int |
| if i := strings.Index(text, commentStart); i > 2 { |
| // Get the text before the commentStart. |
| pre := text[i-2 : i] |
| if pre != "//" { |
| return "", 0 |
| } |
| text = text[i:] |
| adjust = i |
| } |
| if !strings.HasPrefix(text, commentStart) { |
| return "", 0 |
| } |
| text = text[commentStartLen:] |
| return text, commentStartLen + adjust + 1 |
| } |
| |
| const invalidToken rune = 0 |
| |
| type tokens struct { |
| scanner scanner.Scanner |
| current rune |
| err error |
| base token.Pos |
| } |
| |
| func (t *tokens) Init(base token.Pos, text string) *tokens { |
| t.base = base |
| t.scanner.Init(strings.NewReader(text)) |
| t.scanner.Mode = scanner.GoTokens |
| t.scanner.Whitespace ^= 1 << '\n' // don't skip new lines |
| t.scanner.Error = func(s *scanner.Scanner, msg string) { |
| t.Errorf("%v", msg) |
| } |
| return t |
| } |
| |
| func (t *tokens) Consume() string { |
| t.current = invalidToken |
| return t.scanner.TokenText() |
| } |
| |
| func (t *tokens) Token() rune { |
| if t.err != nil { |
| return scanner.EOF |
| } |
| if t.current == invalidToken { |
| t.current = t.scanner.Scan() |
| } |
| return t.current |
| } |
| |
| func (t *tokens) Skip(r rune) int { |
| i := 0 |
| for t.Token() == '\n' { |
| t.Consume() |
| i++ |
| } |
| return i |
| } |
| |
| func (t *tokens) TokenString() string { |
| return scanner.TokenString(t.Token()) |
| } |
| |
| func (t *tokens) Pos() token.Pos { |
| return t.base + token.Pos(t.scanner.Position.Offset) |
| } |
| |
| func (t *tokens) Errorf(msg string, args ...interface{}) { |
| if t.err != nil { |
| return |
| } |
| t.err = fmt.Errorf(msg, args...) |
| } |
| |
| func parse(fset *token.FileSet, base token.Pos, text string) ([]*Note, error) { |
| t := new(tokens).Init(base, text) |
| notes := parseComment(t) |
| if t.err != nil { |
| return nil, fmt.Errorf("%v:%s", fset.Position(t.Pos()), t.err) |
| } |
| return notes, nil |
| } |
| |
| func parseComment(t *tokens) []*Note { |
| var notes []*Note |
| for { |
| t.Skip('\n') |
| switch t.Token() { |
| case scanner.EOF: |
| return notes |
| case scanner.Ident: |
| notes = append(notes, parseNote(t)) |
| default: |
| t.Errorf("unexpected %s parsing comment, expect identifier", t.TokenString()) |
| return nil |
| } |
| switch t.Token() { |
| case scanner.EOF: |
| return notes |
| case ',', '\n': |
| t.Consume() |
| default: |
| t.Errorf("unexpected %s parsing comment, expect separator", t.TokenString()) |
| return nil |
| } |
| } |
| } |
| |
| func parseNote(t *tokens) *Note { |
| n := &Note{ |
| Pos: t.Pos(), |
| Name: t.Consume(), |
| } |
| |
| switch t.Token() { |
| case ',', '\n', scanner.EOF: |
| // no argument list present |
| return n |
| case '(': |
| n.Args = parseArgumentList(t) |
| return n |
| default: |
| t.Errorf("unexpected %s parsing note", t.TokenString()) |
| return nil |
| } |
| } |
| |
| func parseArgumentList(t *tokens) []interface{} { |
| args := []interface{}{} // @name() is represented by a non-nil empty slice. |
| t.Consume() // '(' |
| t.Skip('\n') |
| for t.Token() != ')' { |
| args = append(args, parseArgument(t)) |
| if t.Token() != ',' { |
| break |
| } |
| t.Consume() |
| t.Skip('\n') |
| } |
| if t.Token() != ')' { |
| t.Errorf("unexpected %s parsing argument list", t.TokenString()) |
| return nil |
| } |
| t.Consume() // ')' |
| return args |
| } |
| |
| func parseArgument(t *tokens) interface{} { |
| switch t.Token() { |
| case scanner.Ident: |
| v := t.Consume() |
| switch v { |
| case "true": |
| return true |
| case "false": |
| return false |
| case "nil": |
| return nil |
| case "re": |
| if t.Token() != scanner.String && t.Token() != scanner.RawString { |
| t.Errorf("re must be followed by string, got %s", t.TokenString()) |
| return nil |
| } |
| pattern, _ := strconv.Unquote(t.Consume()) // can't fail |
| re, err := regexp.Compile(pattern) |
| if err != nil { |
| t.Errorf("invalid regular expression %s: %v", pattern, err) |
| return nil |
| } |
| return re |
| default: |
| return Identifier(v) |
| } |
| |
| case scanner.String, scanner.RawString: |
| v, _ := strconv.Unquote(t.Consume()) // can't fail |
| return v |
| |
| case scanner.Int: |
| s := t.Consume() |
| v, err := strconv.ParseInt(s, 0, 0) |
| if err != nil { |
| t.Errorf("cannot convert %v to int: %v", s, err) |
| } |
| return v |
| |
| case scanner.Float: |
| s := t.Consume() |
| v, err := strconv.ParseFloat(s, 64) |
| if err != nil { |
| t.Errorf("cannot convert %v to float: %v", s, err) |
| } |
| return v |
| |
| case scanner.Char: |
| t.Errorf("unexpected char literal %s", t.Consume()) |
| return nil |
| |
| default: |
| t.Errorf("unexpected %s parsing argument", t.TokenString()) |
| return nil |
| } |
| } |
