diff options
Diffstat (limited to 'src/go')
| -rw-r--r-- | src/go/format/format.go | 207 | ||||
| -rw-r--r-- | src/go/format/format_test.go | 6 |
2 files changed, 131 insertions, 82 deletions
diff --git a/src/go/format/format.go b/src/go/format/format.go index 3d00a645d..08a9047b9 100644 --- a/src/go/format/format.go +++ b/src/go/format/format.go @@ -18,6 +18,8 @@ import ( var config = printer.Config{Mode: printer.UseSpaces | printer.TabIndent, Tabwidth: 8} +const parserMode = parser.ParseComments + // Node formats node in canonical gofmt style and writes the result to dst. // // The node type must be *ast.File, *printer.CommentedNode, []ast.Decl, @@ -52,7 +54,7 @@ func Node(dst io.Writer, fset *token.FileSet, node interface{}) error { if err != nil { return err } - file, err = parser.ParseFile(fset, "", buf.Bytes(), parser.ParseComments) + file, err = parser.ParseFile(fset, "", buf.Bytes(), parserMode) if err != nil { // We should never get here. If we do, provide good diagnostic. return fmt.Errorf("format.Node internal error (%s)", err) @@ -80,66 +82,12 @@ func Node(dst io.Writer, fset *token.FileSet, node interface{}) error { // func Source(src []byte) ([]byte, error) { fset := token.NewFileSet() - node, err := parse(fset, src) + file, sourceAdj, indentAdj, err := parse(fset, "", src, true) if err != nil { return nil, err } - var buf bytes.Buffer - if file, ok := node.(*ast.File); ok { - // Complete source file. - ast.SortImports(fset, file) - err := config.Fprint(&buf, fset, file) - if err != nil { - return nil, err - } - - } else { - // Partial source file. - // Determine and prepend leading space. - i, j := 0, 0 - for j < len(src) && isSpace(src[j]) { - if src[j] == '\n' { - i = j + 1 // index of last line in leading space - } - j++ - } - buf.Write(src[:i]) - - // Determine indentation of first code line. - // Spaces are ignored unless there are no tabs, - // in which case spaces count as one tab. - indent := 0 - hasSpace := false - for _, b := range src[i:j] { - switch b { - case ' ': - hasSpace = true - case '\t': - indent++ - } - } - if indent == 0 && hasSpace { - indent = 1 - } - - // Format the source. - cfg := config - cfg.Indent = indent - err := cfg.Fprint(&buf, fset, node) - if err != nil { - return nil, err - } - - // Determine and append trailing space. - i = len(src) - for i > 0 && isSpace(src[i-1]) { - i-- - } - buf.Write(src[i:]) - } - - return buf.Bytes(), nil + return format(fset, file, sourceAdj, indentAdj, src) } func hasUnsortedImports(file *ast.File) bool { @@ -160,40 +108,137 @@ func hasUnsortedImports(file *ast.File) bool { return false } -func isSpace(b byte) bool { - return b == ' ' || b == '\t' || b == '\n' || b == '\r' -} +// parse parses src, which was read from filename, +// as a Go source file or statement list. +func parse(fset *token.FileSet, filename string, src []byte, fragmentOk bool) ( + file *ast.File, + sourceAdj func(src []byte, indent int) []byte, + indentAdj int, + err error, +) { + // Try as whole source file. + file, err = parser.ParseFile(fset, filename, src, parserMode) + // If there's no error, return. If the error is that the source file didn't begin with a + // package line and source fragments are ok, fall through to + // try as a source fragment. Stop and return on any other error. + if err == nil || !fragmentOk || !strings.Contains(err.Error(), "expected 'package'") { + return + } -func parse(fset *token.FileSet, src []byte) (interface{}, error) { - // Try as a complete source file. - file, err := parser.ParseFile(fset, "", src, parser.ParseComments) + // If this is a declaration list, make it a source file + // by inserting a package clause. + // Insert using a ;, not a newline, so that the line numbers + // in psrc match the ones in src. + psrc := append([]byte("package p;"), src...) + file, err = parser.ParseFile(fset, filename, psrc, parserMode) if err == nil { - return file, nil + sourceAdj = func(src []byte, indent int) []byte { + // Remove the package clause. + // Gofmt has turned the ; into a \n. + src = src[indent+len("package p\n"):] + return bytes.TrimSpace(src) + } + return } - // If the source is missing a package clause, try as a source fragment; otherwise fail. - if !strings.Contains(err.Error(), "expected 'package'") { - return nil, err + // If the error is that the source file didn't begin with a + // declaration, fall through to try as a statement list. + // Stop and return on any other error. + if !strings.Contains(err.Error(), "expected declaration") { + return } - // Try as a declaration list by prepending a package clause in front of src. - // Use ';' not '\n' to keep line numbers intact. - psrc := append([]byte("package p;"), src...) - file, err = parser.ParseFile(fset, "", psrc, parser.ParseComments) + // If this is a statement list, make it a source file + // by inserting a package clause and turning the list + // into a function body. This handles expressions too. + // Insert using a ;, not a newline, so that the line numbers + // in fsrc match the ones in src. + fsrc := append(append([]byte("package p; func _() {"), src...), '\n', '}') + file, err = parser.ParseFile(fset, filename, fsrc, parserMode) if err == nil { - return file.Decls, nil + sourceAdj = func(src []byte, indent int) []byte { + // Cap adjusted indent to zero. + if indent < 0 { + indent = 0 + } + // Remove the wrapping. + // Gofmt has turned the ; into a \n\n. + // There will be two non-blank lines with indent, hence 2*indent. + src = src[2*indent+len("package p\n\nfunc _() {"):] + src = src[:len(src)-(indent+len("\n}\n"))] + return bytes.TrimSpace(src) + } + // Gofmt has also indented the function body one level. + // Adjust that with indentAdj. + indentAdj = -1 } - // If the source is missing a declaration, try as a statement list; otherwise fail. - if !strings.Contains(err.Error(), "expected declaration") { + + // Succeeded, or out of options. + return +} + +func format(fset *token.FileSet, file *ast.File, sourceAdj func(src []byte, indent int) []byte, indentAdj int, src []byte) ([]byte, error) { + if sourceAdj == nil { + // Complete source file. + ast.SortImports(fset, file) + var buf bytes.Buffer + err := config.Fprint(&buf, fset, file) + if err != nil { + return nil, err + } + return buf.Bytes(), nil + } + + // Partial source file. + // Determine and prepend leading space. + i, j := 0, 0 + for j < len(src) && isSpace(src[j]) { + if src[j] == '\n' { + i = j + 1 // byte offset of last line in leading space + } + j++ + } + var res []byte + res = append(res, src[:i]...) + + // Determine and prepend indentation of first code line. + // Spaces are ignored unless there are no tabs, + // in which case spaces count as one tab. + indent := 0 + hasSpace := false + for _, b := range src[i:j] { + switch b { + case ' ': + hasSpace = true + case '\t': + indent++ + } + } + if indent == 0 && hasSpace { + indent = 1 + } + for i := 0; i < indent; i++ { + res = append(res, '\t') + } + + // Format the source. + // Write it without any leading and trailing space. + cfg := config + cfg.Indent = indent + indentAdj + var buf bytes.Buffer + err := cfg.Fprint(&buf, fset, file) + if err != nil { return nil, err } + res = append(res, sourceAdj(buf.Bytes(), cfg.Indent)...) - // Try as statement list by wrapping a function around src. - fsrc := append(append([]byte("package p; func _() {"), src...), '}') - file, err = parser.ParseFile(fset, "", fsrc, parser.ParseComments) - if err == nil { - return file.Decls[0].(*ast.FuncDecl).Body.List, nil + // Determine and append trailing space. + i = len(src) + for i > 0 && isSpace(src[i-1]) { + i-- } + return append(res, src[i:]...), nil +} - // Failed, and out of options. - return nil, err +func isSpace(b byte) bool { + return b == ' ' || b == '\t' || b == '\n' || b == '\r' } diff --git a/src/go/format/format_test.go b/src/go/format/format_test.go index 93f099247..d7846bec6 100644 --- a/src/go/format/format_test.go +++ b/src/go/format/format_test.go @@ -87,7 +87,11 @@ var tests = []string{ "\tx := 0\n\tgo f()\n\n\n", "\n\t\t\n\n\tx := 0\n\tgo f()\n\n\n", "\n\t\t\n\n\t\t\tx := 0\n\t\t\tgo f()\n\n\n", - "\n\t\t\n\n\t\t\tx := 0\n\t\t\tconst s = `\nfoo\n`\n\n\n", // no indentation inside raw strings + "\n\t\t\n\n\t\t\tx := 0\n\t\t\tconst s = `\nfoo\n`\n\n\n", // no indentation added inside raw strings + "\n\t\t\n\n\t\t\tx := 0\n\t\t\tconst s = `\n\t\tfoo\n`\n\n\n", // no indentation removed inside raw strings + + // comments + "i := 5 /* Comment */", // Issue 5551. // erroneous programs "ERROR1 + 2 +", |