| package main |
| |
| import ( |
| "bufio" |
| "bytes" |
| "errors" |
| "fmt" |
| "io" |
| "os" |
| ) |
| |
| type Makefile struct { |
| stmts []AST |
| } |
| |
| type parser struct { |
| rd *bufio.Reader |
| mk Makefile |
| filename string |
| lineno int |
| elineno int // lineno == elineno unless there is trailing '\'. |
| unBuf []byte |
| hasUnBuf bool |
| done bool |
| } |
| |
| func exists(filename string) bool { |
| f, err := os.Open(filename) |
| if err != nil { |
| return false |
| } |
| f.Close() |
| return true |
| } |
| |
| func newParser(rd io.Reader, filename string) *parser { |
| return &parser{ |
| rd: bufio.NewReader(rd), |
| filename: filename, |
| } |
| } |
| |
| func (p *parser) readLine() []byte { |
| if p.hasUnBuf { |
| p.hasUnBuf = false |
| return p.unBuf |
| } |
| |
| p.lineno = p.elineno |
| line, err := p.rd.ReadBytes('\n') |
| p.lineno++ |
| p.elineno = p.lineno |
| if err == io.EOF { |
| p.done = true |
| } else if err != nil { |
| panic(err) |
| } |
| |
| if len(line) > 0 { |
| line = line[0 : len(line)-1] |
| } |
| |
| // TODO: Handle \\ at the end of the line? |
| for len(line) > 0 && line[len(line)-1] == '\\' { |
| line = line[:len(line)-1] |
| nline := p.readLine() |
| p.elineno++ |
| line = append(line, nline...) |
| } |
| |
| index := bytes.IndexByte(line, '#') |
| if index >= 0 { |
| line = line[:index] |
| } |
| |
| return line |
| } |
| |
| func (p *parser) unreadLine(line []byte) { |
| if p.hasUnBuf { |
| panic("unreadLine twice!") |
| } |
| p.unBuf = line |
| p.hasUnBuf = true |
| } |
| |
| func (p *parser) parseAssign(line []byte, sep int, typ int) AST { |
| Log("parseAssign %s %d", line, sep) |
| esep := sep + 1 |
| if typ != ASSIGN_RECURSIVE { |
| esep++ |
| } |
| lhs := string(bytes.TrimSpace(line[:sep])) |
| rhs := string(bytes.TrimLeft(line[esep:], " \t")) |
| ast := &AssignAST{lhs: lhs, rhs: rhs, assign_type: typ} |
| ast.filename = p.filename |
| ast.lineno = p.lineno |
| return ast |
| } |
| |
| func (p *parser) parseRule(line []byte, sep int) AST { |
| lhs := string(bytes.TrimSpace(line[:sep])) |
| rhs := string(bytes.TrimSpace(line[sep+1:])) |
| ast := &RuleAST{ |
| lhs: lhs, |
| rhs: rhs, |
| } |
| ast.filename = p.filename |
| ast.lineno = p.lineno |
| for { |
| line := p.readLine() |
| if len(line) == 0 { |
| break |
| } else if line[0] == '\t' { |
| ast.cmds = append(ast.cmds, string(bytes.TrimSpace(line))) |
| } else { |
| p.unreadLine(line) |
| break |
| } |
| } |
| return ast |
| } |
| |
| func (p *parser) parse() (mk Makefile, err error) { |
| defer func() { |
| if r := recover(); r != nil { |
| err = fmt.Errorf("panic: %v", r) |
| } |
| }() |
| for !p.done { |
| line := p.readLine() |
| |
| var ast AST |
| for i, ch := range line { |
| switch ch { |
| case ':': |
| if i+1 < len(line) && line[i+1] == '=' { |
| ast = p.parseAssign(line, i, ASSIGN_SIMPLE) |
| } else { |
| ast = p.parseRule(line, i) |
| } |
| case '=': |
| ast = p.parseAssign(line, i, ASSIGN_RECURSIVE) |
| case '?': |
| panic("TODO") |
| } |
| if ast != nil { |
| p.mk.stmts = append(p.mk.stmts, ast) |
| break |
| } |
| } |
| if ast == nil && len(bytes.TrimSpace(line)) > 0 { |
| a := &RawExprAST{expr: string(line)} |
| a.filename = p.filename |
| a.lineno = p.lineno |
| p.mk.stmts = append(p.mk.stmts, a) |
| } |
| } |
| return p.mk, nil |
| } |
| |
| func ParseMakefile(filename string) (Makefile, error) { |
| f, err := os.Open(filename) |
| if err != nil { |
| return Makefile{}, err |
| } |
| defer f.Close() |
| parser := newParser(f, filename) |
| return parser.parse() |
| } |
| |
| func ParseDefaultMakefile() (Makefile, error) { |
| candidates := []string{"GNUmakefile", "makefile", "Makefile"} |
| for _, filename := range candidates { |
| if exists(filename) { |
| return ParseMakefile(filename) |
| } |
| } |
| return Makefile{}, errors.New("no targets specified and no makefile found.") |
| } |