mirror of
https://github.com/golang/go
synced 2024-11-19 23:44:43 -07:00
go/scanner: recognize //line and /*line directives incl. columns
This change updates go/scanner to recognize the extended line directives that are now also handled by cmd/compile: //line filename:line //line filename:line:column /*line filename:line*/ /*line filename:line:column*/ As before, //-style line directives must start in column 1. /*-style line directives may be placed anywhere in the code. In both cases, the specified position applies to the character immediately following the comment; for line comments that is the first character on the next line (after the newline of the comment). The go/token API is extended by a new method File.AddLineColumnInfo(offset int, filename string, line, column int) which extends the existing File.AddLineInfo(offset int, filename string, line int) by adding a column parameter. Adjusted token.Position computation is changed to take into account column information if provided via a line directive: A (line-directive) relative position will have a non-zero column iff the line directive specified a column; if the position is on the same line as the line directive, the column is relative to the specified column (otherwise it is relative to the line beginning). See also #24183. Finally, Position.String() has been adjusted to not print a column value if the column is unknown (== 0). Fixes #24143. Change-Id: I5518c825ad94443365c049a95677407b46ba55a1 Reviewed-on: https://go-review.googlesource.com/97795 Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This commit is contained in:
Robert Griesemer
parent
20046020c4
commit
99c30211b1
@ -141,46 +141,26 @@ func (s *Scanner) error(offs int, msg string) {
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s.ErrorCount++
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}
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var prefix = []byte("//line ")
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func (s *Scanner) interpretLineComment(text []byte) {
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if bytes.HasPrefix(text, prefix) {
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// get filename and line number, if any
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if i := bytes.LastIndex(text, []byte{':'}); i > 0 {
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if line, err := strconv.Atoi(string(text[i+1:])); err == nil && line > 0 {
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// valid //line filename:line comment
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filename := string(bytes.TrimSpace(text[len(prefix):i]))
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if filename != "" {
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filename = filepath.Clean(filename)
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if !filepath.IsAbs(filename) {
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// make filename relative to current directory
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filename = filepath.Join(s.dir, filename)
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}
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}
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// update scanner position
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s.file.AddLineInfo(s.lineOffset+len(text)+1, filename, line) // +len(text)+1 since comment applies to next line
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}
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}
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}
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}
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func (s *Scanner) scanComment() string {
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// initial '/' already consumed; s.ch == '/' || s.ch == '*'
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offs := s.offset - 1 // position of initial '/'
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hasCR := false
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next := -1 // position immediately following the comment; < 0 means invalid comment
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numCR := 0
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if s.ch == '/' {
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//-style comment
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// (the final '\n' is not considered part of the comment)
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s.next()
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for s.ch != '\n' && s.ch >= 0 {
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if s.ch == '\r' {
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hasCR = true
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numCR++
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}
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s.next()
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}
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if offs == s.lineOffset {
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// comment starts at the beginning of the current line
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s.interpretLineComment(s.src[offs:s.offset])
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// if we are at '\n', the position following the comment is afterwards
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next = s.offset
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if s.ch == '\n' {
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next++
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}
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goto exit
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}
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@ -190,11 +170,12 @@ func (s *Scanner) scanComment() string {
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for s.ch >= 0 {
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ch := s.ch
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if ch == '\r' {
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hasCR = true
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numCR++
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}
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s.next()
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if ch == '*' && s.ch == '/' {
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s.next()
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next = s.offset
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goto exit
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}
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}
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@ -203,13 +184,116 @@ func (s *Scanner) scanComment() string {
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exit:
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lit := s.src[offs:s.offset]
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if hasCR {
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// On Windows, a (//-comment) line may end in "\r\n".
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// Remove the final '\r' before analyzing the text for
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// line directives (matching the compiler). Remove any
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// other '\r' afterwards (matching the pre-existing be-
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// havior of the scanner).
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if numCR > 0 && len(lit) >= 2 && lit[1] == '/' && lit[len(lit)-1] == '\r' {
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lit = lit[:len(lit)-1]
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numCR--
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}
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// interpret line directives
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// (//line directives must start at the beginning of the current line)
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if next >= 0 /* implies valid comment */ && (lit[1] == '*' || offs == s.lineOffset) && bytes.HasPrefix(lit[2:], prefix) {
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s.updateLineInfo(next, offs, lit)
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}
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if numCR > 0 {
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lit = stripCR(lit, lit[1] == '*')
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}
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return string(lit)
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}
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var prefix = []byte("line ")
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// updateLineInfo parses the incoming comment text at offset offs
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// as a line directive. If successful, it updates the line info table
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// for the position next per the line directive.
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func (s *Scanner) updateLineInfo(next, offs int, text []byte) {
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// the existing code used to ignore incorrect line/column values
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// TODO(gri) adjust once we agree on the directive syntax (issue #24183)
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reportErrors := false
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// extract comment text
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if text[1] == '*' {
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text = text[:len(text)-2] // lop off trailing "*/"
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}
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text = text[7:] // lop off leading "//line " or "/*line "
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offs += 7
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i, n, ok := trailingDigits(text)
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if i == 0 {
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return // ignore (not a line directive)
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}
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// i > 0
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if !ok {
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// text has a suffix :xxx but xxx is not a number
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if reportErrors {
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s.error(offs+i, "invalid line number: "+string(text[i:]))
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}
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return
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}
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var line, col int
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i2, n2, ok2 := trailingDigits(text[:i-1])
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if ok2 {
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//line filename:line:col
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i, i2 = i2, i
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line, col = n2, n
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if col == 0 {
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if reportErrors {
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s.error(offs+i2, "invalid column number: "+string(text[i2:]))
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}
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return
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}
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text = text[:i2-1] // lop off ":col"
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} else {
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//line filename:line
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line = n
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}
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if line == 0 {
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if reportErrors {
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s.error(offs+i, "invalid line number: "+string(text[i:]))
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}
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return
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}
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// the existing code used to trim whitespace around filenames
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// TODO(gri) adjust once we agree on the directive syntax (issue #24183)
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filename := string(bytes.TrimSpace(text[:i-1])) // lop off ":line", and trim white space
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// If we have a column (//line filename:line:col form),
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// an empty filename means to use the previous filename.
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if filename != "" {
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filename = filepath.Clean(filename)
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if !filepath.IsAbs(filename) {
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// make filename relative to current directory
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filename = filepath.Join(s.dir, filename)
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}
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} else if ok2 {
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// use existing filename
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filename = s.file.Position(s.file.Pos(offs)).Filename
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}
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s.file.AddLineColumnInfo(next, filename, line, col)
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}
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func trailingDigits(text []byte) (int, int, bool) {
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i := bytes.LastIndexByte(text, ':') // look from right (Windows filenames may contain ':')
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if i < 0 {
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return 0, 0, false // no ":"
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}
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// i >= 0
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n, err := strconv.ParseUint(string(text[i+1:]), 10, 0)
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return i + 1, int(n), err == nil
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}
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func (s *Scanner) findLineEnd() bool {
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// initial '/' already consumed
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@ -503,39 +503,52 @@ func TestSemis(t *testing.T) {
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}
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type segment struct {
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srcline string // a line of source text
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filename string // filename for current token
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line int // line number for current token
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srcline string // a line of source text
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filename string // filename for current token
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line, column int // line number for current token
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}
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var segments = []segment{
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// exactly one token per line since the test consumes one token per segment
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{" line1", filepath.Join("dir", "TestLineComments"), 1},
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{"\nline2", filepath.Join("dir", "TestLineComments"), 2},
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{"\nline3 //line File1.go:100", filepath.Join("dir", "TestLineComments"), 3}, // bad line comment, ignored
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{"\nline4", filepath.Join("dir", "TestLineComments"), 4},
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{"\n//line File1.go:100\n line100", filepath.Join("dir", "File1.go"), 100},
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{"\n//line \t :42\n line1", "", 42},
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{"\n//line File2.go:200\n line200", filepath.Join("dir", "File2.go"), 200},
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{"\n//line foo\t:42\n line42", filepath.Join("dir", "foo"), 42},
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{"\n //line foo:42\n line44", filepath.Join("dir", "foo"), 44}, // bad line comment, ignored
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{"\n//line foo 42\n line46", filepath.Join("dir", "foo"), 46}, // bad line comment, ignored
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{"\n//line foo:42 extra text\n line48", filepath.Join("dir", "foo"), 48}, // bad line comment, ignored
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{"\n//line ./foo:42\n line42", filepath.Join("dir", "foo"), 42},
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{"\n//line a/b/c/File1.go:100\n line100", filepath.Join("dir", "a", "b", "c", "File1.go"), 100},
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{" line1", filepath.Join("dir", "TestLineDirectives"), 1, 3},
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{"\nline2", filepath.Join("dir", "TestLineDirectives"), 2, 1},
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{"\nline3 //line File1.go:100", filepath.Join("dir", "TestLineDirectives"), 3, 1}, // bad line comment, ignored
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{"\nline4", filepath.Join("dir", "TestLineDirectives"), 4, 1},
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{"\n//line File1.go:100\n line100", filepath.Join("dir", "File1.go"), 100, 0},
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{"\n//line \t :42\n line1", "", 42, 0},
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{"\n//line File2.go:200\n line200", filepath.Join("dir", "File2.go"), 200, 0},
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{"\n//line foo\t:42\n line42", filepath.Join("dir", "foo"), 42, 0},
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{"\n //line foo:42\n line44", filepath.Join("dir", "foo"), 44, 0}, // bad line comment, ignored
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{"\n//line foo 42\n line46", filepath.Join("dir", "foo"), 46, 0}, // bad line comment, ignored
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{"\n//line foo:42 extra text\n line48", filepath.Join("dir", "foo"), 48, 0}, // bad line comment, ignored
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{"\n//line ./foo:42\n line42", filepath.Join("dir", "foo"), 42, 0},
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{"\n//line a/b/c/File1.go:100\n line100", filepath.Join("dir", "a", "b", "c", "File1.go"), 100, 0},
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// tests for new line directive syntax
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{"\n//line :100\na1", "", 100, 0}, // missing filename means empty filename
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{"\n//line bar:100\nb1", filepath.Join("dir", "bar"), 100, 0},
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{"\n//line :100:10\nc1", filepath.Join("dir", "bar"), 100, 10}, // missing filename means current filename
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{"\n//line foo:100:10\nd1", filepath.Join("dir", "foo"), 100, 10},
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{"\n/*line :100*/a2", "", 100, 0}, // missing filename means empty filename
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{"\n/*line bar:100*/b2", filepath.Join("dir", "bar"), 100, 0},
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{"\n/*line :100:10*/c2", filepath.Join("dir", "bar"), 100, 10}, // missing filename means current filename
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{"\n/*line foo:100:10*/d2", filepath.Join("dir", "foo"), 100, 10},
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{"\n/*line foo:100:10*/ e2", filepath.Join("dir", "foo"), 100, 14}, // line-directive relative column
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{"\n/*line foo:100:10*/\n\nf2", filepath.Join("dir", "foo"), 102, 1}, // absolute column since on new line
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}
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var unixsegments = []segment{
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{"\n//line /bar:42\n line42", "/bar", 42},
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{"\n//line /bar:42\n line42", "/bar", 42, 0},
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}
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var winsegments = []segment{
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{"\n//line c:\\bar:42\n line42", "c:\\bar", 42},
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{"\n//line c:\\dir\\File1.go:100\n line100", "c:\\dir\\File1.go", 100},
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{"\n//line c:\\bar:42\n line42", "c:\\bar", 42, 0},
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{"\n//line c:\\dir\\File1.go:100\n line100", "c:\\dir\\File1.go", 100, 0},
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}
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// Verify that comments of the form "//line filename:line" are interpreted correctly.
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func TestLineComments(t *testing.T) {
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// Verify that line directives are interpreted correctly.
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func TestLineDirectives(t *testing.T) {
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segs := segments
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if runtime.GOOS == "windows" {
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segs = append(segs, winsegments...)
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@ -551,8 +564,8 @@ func TestLineComments(t *testing.T) {
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// verify scan
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var S Scanner
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file := fset.AddFile(filepath.Join("dir", "TestLineComments"), fset.Base(), len(src))
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S.Init(file, []byte(src), nil, dontInsertSemis)
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file := fset.AddFile(filepath.Join("dir", "TestLineDirectives"), fset.Base(), len(src))
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S.Init(file, []byte(src), func(pos token.Position, msg string) { t.Error(Error{pos, msg}) }, dontInsertSemis)
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for _, s := range segs {
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p, _, lit := S.Scan()
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pos := file.Position(p)
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@ -560,7 +573,7 @@ func TestLineComments(t *testing.T) {
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Filename: s.filename,
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Offset: pos.Offset,
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Line: s.line,
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Column: pos.Column,
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Column: s.column,
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})
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}
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@ -30,7 +30,9 @@ func (pos *Position) IsValid() bool { return pos.Line > 0 }
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// String returns a string in one of several forms:
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//
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// file:line:column valid position with file name
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// file:line valid position with file name but no column (column == 0)
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// line:column valid position without file name
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// line valid position without file name and no column (column == 0)
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// file invalid position with file name
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// - invalid position without file name
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//
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@ -40,7 +42,10 @@ func (pos Position) String() string {
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if s != "" {
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s += ":"
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}
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s += fmt.Sprintf("%d:%d", pos.Line, pos.Column)
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s += fmt.Sprintf("%d", pos.Line)
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if pos.Column != 0 {
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s += fmt.Sprintf(":%d", pos.Column)
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}
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}
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if s == "" {
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s = "-"
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@ -204,28 +209,36 @@ func (f *File) SetLinesForContent(content []byte) {
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f.mutex.Unlock()
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}
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// A lineInfo object describes alternative file and line number
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// information (such as provided via a //line comment in a .go
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// file) for a given file offset.
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// A lineInfo object describes alternative file, line, and column
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// number information (such as provided via a //line directive)
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// for a given file offset.
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type lineInfo struct {
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// fields are exported to make them accessible to gob
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Offset int
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Filename string
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Line int
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Offset int
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Filename string
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Line, Column int
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}
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// AddLineInfo adds alternative file and line number information for
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// a given file offset. The offset must be larger than the offset for
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// the previously added alternative line info and smaller than the
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// file size; otherwise the information is ignored.
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//
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// AddLineInfo is typically used to register alternative position
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// information for //line filename:line comments in source files.
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// AddLineInfo is like AddLineColumnInfo with a column = 1 argument.
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// It is here for backward-compatibility for code prior to Go 1.11.
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//
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func (f *File) AddLineInfo(offset int, filename string, line int) {
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f.AddLineColumnInfo(offset, filename, line, 1)
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}
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// AddLineColumnInfo adds alternative file, line, and column number
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// information for a given file offset. The offset must be larger
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// than the offset for the previously added alternative line info
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// and smaller than the file size; otherwise the information is
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// ignored.
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//
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// AddLineColumnInfo is typically used to register alternative position
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// information for line directives such as //line filename:line:column.
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//
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func (f *File) AddLineColumnInfo(offset int, filename string, line, column int) {
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f.mutex.Lock()
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if i := len(f.infos); i == 0 || f.infos[i-1].Offset < offset && offset < f.size {
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f.infos = append(f.infos, lineInfo{offset, filename, line})
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f.infos = append(f.infos, lineInfo{offset, filename, line, column})
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}
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f.mutex.Unlock()
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}
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@ -275,12 +288,25 @@ func (f *File) unpack(offset int, adjusted bool) (filename string, line, column
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line, column = i+1, offset-f.lines[i]+1
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}
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if adjusted && len(f.infos) > 0 {
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// almost no files have extra line infos
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// few files have extra line infos
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if i := searchLineInfos(f.infos, offset); i >= 0 {
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alt := &f.infos[i]
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filename = alt.Filename
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if i := searchInts(f.lines, alt.Offset); i >= 0 {
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line += alt.Line - i - 1
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// i+1 is the line at which the alternative position was recorded
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d := line - (i + 1) // line distance from alternative position base
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line = alt.Line + d
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if alt.Column == 0 {
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// alternative column is unknown => relative column is unknown
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// (the current specification for line directives requires
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// this to apply until the next PosBase/line directive,
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// not just until the new newline)
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column = 0
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} else if d == 0 {
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// the alternative position base is on the current line
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// => column is relative to alternative column
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column = alt.Column + (offset - alt.Offset)
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}
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}
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}
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}
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