| package main |
| |
| import ( |
| "bufio" |
| "bytes" |
| "errors" |
| "fmt" |
| "io" |
| "os" |
| "strings" |
| ) |
| |
| type Makefile struct { |
| stmts []AST |
| } |
| |
| type ifState struct { |
| ast *IfAST |
| inElse bool |
| } |
| |
| 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 |
| outStmts *[]AST |
| ifStack []ifState |
| } |
| |
| 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 { |
| p := &parser{ |
| rd: bufio.NewReader(rd), |
| filename: filename, |
| } |
| p.outStmts = &p.mk.stmts |
| return p |
| } |
| |
| func (p *parser) addStatement(ast AST) { |
| *p.outStmts = append(*p.outStmts, ast) |
| } |
| |
| 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, esep int) AST { |
| Log("parseAssign %s %s", line, line[sep:esep]) |
| ast := &AssignAST{ |
| lhs: string(bytes.TrimSpace(line[:sep])), |
| rhs: string(bytes.TrimLeft(line[esep:], " \t")), |
| op: string(line[sep:esep]), |
| } |
| ast.filename = p.filename |
| ast.lineno = p.lineno |
| return ast |
| } |
| |
| func (p *parser) parseMaybeRule(line string) AST { |
| if len(strings.TrimSpace(line)) == 0 { |
| return nil |
| } |
| if line[0] == '\t' { |
| Error(p.filename, p.lineno, "*** commands commence before first target.") |
| } |
| |
| ast := &MaybeRuleAST{ |
| expr: line, |
| } |
| ast.filename = p.filename |
| ast.lineno = p.lineno |
| ast.cmdLineno = p.elineno + 1 |
| 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) parseInclude(line string, oplen int) AST { |
| ast := &IncludeAST{ |
| expr: line[oplen+1:], |
| op: line[:oplen], |
| } |
| ast.filename = p.filename |
| ast.lineno = p.lineno |
| return ast |
| } |
| |
| func (p *parser) parseIfdef(line string, oplen int) AST { |
| ast := &IfAST{ |
| op: line[:oplen], |
| lhs: strings.TrimSpace(line[oplen+1:]), |
| } |
| ast.filename = p.filename |
| ast.lineno = p.lineno |
| p.addStatement(ast) |
| p.ifStack = append(p.ifStack, ifState{ast: ast}) |
| p.outStmts = &ast.trueStmts |
| return ast |
| } |
| |
| func closeParen(ch byte) (byte, error) { |
| switch ch { |
| case '(': |
| return ')', nil |
| case '{': |
| return '}', nil |
| default: |
| return 0, fmt.Errorf("unexpected paren %c", ch) |
| } |
| } |
| |
| // parseExpr parses s as expr. |
| // The expr should starts with '(' or '{' and returns strings |
| // separeted by ',' before ')' or '}' respectively, and an index for the rest. |
| func parseExpr(s string) ([]string, int, error) { |
| if len(s) == 0 { |
| return nil, 0, errors.New("empty expr") |
| } |
| paren, err := closeParen(s[0]) |
| if err != nil { |
| return nil, 0, err |
| } |
| parenCnt := make(map[byte]int) |
| i := 0 |
| ia := 1 |
| var args []string |
| Loop: |
| for { |
| i++ |
| if i == len(s) { |
| return nil, 0, errors.New("unexpected end of expr") |
| } |
| ch := s[i] |
| switch ch { |
| case '(', '{': |
| cch, err := closeParen(ch) |
| if err != nil { |
| return nil, 0, err |
| } |
| parenCnt[cch]++ |
| case ')', '}': |
| parenCnt[ch]-- |
| if ch == paren && parenCnt[ch] < 0 { |
| break Loop |
| } |
| case ',': |
| if parenCnt[')'] == 0 && parenCnt['}'] == 0 { |
| args = append(args, s[ia:i]) |
| ia = i + 1 |
| } |
| } |
| } |
| args = append(args, s[ia:i]) |
| return args, i + 1, nil |
| } |
| |
| func parseEq(s string) (string, string, bool) { |
| args, _, err := parseExpr(s) |
| if err != nil { |
| return "", "", false |
| } |
| if len(args) != 2 { |
| return "", "", false |
| } |
| // TODO: check rest? |
| return args[0], args[1], true |
| } |
| |
| func (p *parser) parseIfeq(line string, oplen int) AST { |
| lhs, rhs, ok := parseEq(strings.TrimSpace(line[oplen+1:])) |
| if !ok { |
| Error(p.filename, p.lineno, `*** invalid syntax in conditional.`) |
| } |
| |
| ast := &IfAST{ |
| op: line[:oplen], |
| lhs: lhs, |
| rhs: rhs, |
| } |
| ast.filename = p.filename |
| ast.lineno = p.lineno |
| p.addStatement(ast) |
| p.ifStack = append(p.ifStack, ifState{ast: ast}) |
| p.outStmts = &ast.trueStmts |
| return ast |
| } |
| |
| func (p *parser) checkIfStack(curKeyword string) { |
| if len(p.ifStack) == 0 { |
| Error(p.filename, p.lineno, `*** extraneous %q.`, curKeyword) |
| } |
| } |
| |
| func (p *parser) parseElse(line string) { |
| p.checkIfStack("else") |
| state := &p.ifStack[len(p.ifStack)-1] |
| if state.inElse { |
| Error(p.filename, p.lineno, `*** only one "else" per conditional.`) |
| } |
| state.inElse = true |
| p.outStmts = &state.ast.falseStmts |
| } |
| |
| func (p *parser) parseEndif(line string) { |
| p.checkIfStack("endif") |
| p.ifStack = p.ifStack[0 : len(p.ifStack)-1] |
| if len(p.ifStack) == 0 { |
| p.outStmts = &p.mk.stmts |
| } else { |
| state := p.ifStack[len(p.ifStack)-1] |
| if state.inElse { |
| p.outStmts = &state.ast.falseStmts |
| } else { |
| p.outStmts = &state.ast.trueStmts |
| } |
| } |
| } |
| |
| func (p *parser) parseKeywords(line string) bool { |
| stripped := strings.TrimLeft(line, " \t") |
| if strings.HasPrefix(stripped, "include ") { |
| p.addStatement(p.parseInclude(stripped, len("include"))) |
| return true |
| } |
| if strings.HasPrefix(stripped, "-include ") { |
| p.addStatement(p.parseInclude(stripped, len("-include"))) |
| return true |
| } |
| if strings.HasPrefix(stripped, "ifdef ") { |
| p.parseIfdef(stripped, len("ifdef")) |
| return true |
| } |
| if strings.HasPrefix(stripped, "ifndef ") { |
| p.parseIfdef(stripped, len("ifndef")) |
| return true |
| } |
| if strings.HasPrefix(stripped, "ifeq ") { |
| p.parseIfeq(stripped, len("ifeq")) |
| return true |
| } |
| if strings.HasPrefix(stripped, "ifneq ") { |
| p.parseIfeq(stripped, len("ifneq")) |
| return true |
| } |
| if strings.HasPrefix(stripped, "else") { |
| p.parseElse(stripped) |
| return true |
| } |
| if strings.HasPrefix(stripped, "endif") { |
| p.parseEndif(stripped) |
| return true |
| } |
| return false |
| } |
| |
| 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() |
| |
| if p.parseKeywords(string(line)) { |
| continue |
| } |
| |
| var ast AST |
| for i, ch := range line { |
| switch ch { |
| case ':': |
| if i+1 < len(line) && line[i+1] == '=' { |
| ast = p.parseAssign(line, i, i+2) |
| } else { |
| ast = p.parseMaybeRule(string(line)) |
| } |
| case '=': |
| ast = p.parseAssign(line, i, i+1) |
| case '?', '+': |
| if i+1 < len(line) && line[i+1] == '=' { |
| ast = p.parseAssign(line, i, i+2) |
| } |
| } |
| if ast != nil { |
| p.addStatement(ast) |
| break |
| } |
| } |
| if ast == nil { |
| ast = p.parseMaybeRule(string(line)) |
| if ast != nil { |
| p.addStatement(ast) |
| } |
| } |
| } |
| 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.") |
| } |