Golang CommentGroup.End方法代码示例

func fixImportCheck(body []byte, importPath string) ([]byte, error) {
	fset := token.NewFileSet()
	// todo: see if we can restrict the mode some more
	f, err := parser.ParseFile(fset, "", body, parser.ParseComments)
	if err != nil {
		log.Fatal(err)
	}
	var after *ast.CommentGroup
	var pos token.Pos = token.Pos(len(body))
	for _, v := range f.Comments {
		text := strings.TrimSpace(v.Text())
		if v.Pos() > f.Package && v.Pos() < pos && strings.HasPrefix(text, "import") {
			pos = v.Pos()
			after = v
		}
	}
	if after != nil && bytes.IndexByte(body[f.Package:pos], '\n') == -1 {
		comment := fmt.Sprintf(`// import "%s"`, importPath)
		buf := new(bytes.Buffer)
		buf.Write(body[:after.Pos()-1])
		buf.WriteString(comment)
		buf.Write(body[after.End()-1:])
		body = buf.Bytes()
	}
	return body, nil
}

// lintPackageComment checks package comments. It complains if
// there is no package comment, or if it is not of the right form.
// This has a notable false positive in that a package comment
// could rightfully appear in a different file of the same package,
// but that's not easy to fix since this linter is file-oriented.
func (f *file) lintPackageComment() {
	if f.isTest() {
		return
	}

	const ref = styleGuideBase + "#package-comments"
	prefix := "Package " + f.f.Name.Name + " "

	// Look for a detached package comment.
	// First, scan for the last comment that occurs before the "package" keyword.
	var lastCG *ast.CommentGroup
	for _, cg := range f.f.Comments {
		if cg.Pos() > f.f.Package {
			// Gone past "package" keyword.
			break
		}
		lastCG = cg
	}
	if lastCG != nil && strings.HasPrefix(lastCG.Text(), prefix) {
		endPos := f.fset.Position(lastCG.End())
		pkgPos := f.fset.Position(f.f.Package)
		if endPos.Line+1 < pkgPos.Line {
			// There isn't a great place to anchor this error;
			// the start of the blank lines between the doc and the package statement
			// is at least pointing at the location of the problem.
			pos := token.Position{
				Filename: endPos.Filename,
				// Offset not set; it is non-trivial, and doesn't appear to be needed.
				Line:   endPos.Line + 1,
				Column: 1,
			}
			f.pkg.errorfAt(pos, 0.9, link(ref), category("comments"), "package comment is detached; there should be no blank lines between it and the package statement")
			return
		}
	}

	if f.f.Doc == nil {
		f.errorf(f.f, 0.2, link(ref), category("comments"), "should have a package comment, unless it's in another file for this package")
		return
	}
	s := f.f.Doc.Text()
	if ts := strings.TrimLeft(s, " \t"); ts != s {
		f.errorf(f.f.Doc, 1, link(ref), category("comments"), "package comment should not have leading space")
		s = ts
	}
	// Only non-main packages need to keep to this form.
	if f.f.Name.Name != "main" && !strings.HasPrefix(s, prefix) {
		f.errorf(f.f.Doc, 1, link(ref), category("comments"), `package comment should be of the form "%s..."`, prefix)
	}
}