Scott Baker | 4a35a70 | 2019-11-26 08:17:33 -0800 | [diff] [blame] | 1 | package protoparse |
| 2 | |
| 3 | import ( |
| 4 | "errors" |
| 5 | "fmt" |
| 6 | ) |
| 7 | |
| 8 | // ErrInvalidSource is a sentinel error that is returned by calls to |
| 9 | // Parser.ParseFiles and Parser.ParseFilesButDoNotLink in the event that syntax |
| 10 | // or link errors are encountered, but the parser's configured ErrorReporter |
| 11 | // always returns nil. |
| 12 | var ErrInvalidSource = errors.New("parse failed: invalid proto source") |
| 13 | |
| 14 | // ErrorReporter is responsible for reporting the given error. If the reporter |
| 15 | // returns a non-nil error, parsing/linking will abort with that error. If the |
| 16 | // reporter returns nil, parsing will continue, allowing the parser to try to |
| 17 | // report as many syntax and/or link errors as it can find. |
| 18 | type ErrorReporter func(err ErrorWithPos) error |
| 19 | |
| 20 | func defaultErrorReporter(err ErrorWithPos) error { |
| 21 | // abort parsing after first error encountered |
| 22 | return err |
| 23 | } |
| 24 | |
| 25 | type errorHandler struct { |
| 26 | reporter ErrorReporter |
| 27 | errsReported bool |
| 28 | err error |
| 29 | } |
| 30 | |
| 31 | func newErrorHandler(reporter ErrorReporter) *errorHandler { |
| 32 | if reporter == nil { |
| 33 | reporter = defaultErrorReporter |
| 34 | } |
| 35 | return &errorHandler{ |
| 36 | reporter: reporter, |
| 37 | } |
| 38 | } |
| 39 | |
| 40 | func (h *errorHandler) handleError(err error) error { |
| 41 | if h.err != nil { |
| 42 | return h.err |
| 43 | } |
| 44 | if ewp, ok := err.(ErrorWithPos); ok { |
| 45 | h.errsReported = true |
| 46 | err = h.reporter(ewp) |
| 47 | } |
| 48 | h.err = err |
| 49 | return err |
| 50 | } |
| 51 | |
| 52 | func (h *errorHandler) getError() error { |
| 53 | if h.errsReported && h.err == nil { |
| 54 | return ErrInvalidSource |
| 55 | } |
| 56 | return h.err |
| 57 | } |
| 58 | |
| 59 | // ErrorWithPos is an error about a proto source file that includes information |
| 60 | // about the location in the file that caused the error. |
| 61 | // |
| 62 | // The value of Error() will contain both the SourcePos and Underlying error. |
| 63 | // The value of Unwrap() will only be the Underlying error. |
| 64 | type ErrorWithPos interface { |
| 65 | error |
| 66 | GetPosition() SourcePos |
| 67 | Unwrap() error |
| 68 | } |
| 69 | |
| 70 | // ErrorWithSourcePos is an error about a proto source file that includes |
| 71 | // information about the location in the file that caused the error. |
| 72 | // |
| 73 | // Errors that include source location information *might* be of this type. |
| 74 | // However, calling code that is trying to examine errors with location info |
| 75 | // should instead look for instances of the ErrorWithPos interface, which |
| 76 | // will find other kinds of errors. This type is only exported for backwards |
| 77 | // compatibility. |
| 78 | type ErrorWithSourcePos struct { |
| 79 | Underlying error |
| 80 | Pos *SourcePos |
| 81 | } |
| 82 | |
| 83 | // Error implements the error interface |
| 84 | func (e ErrorWithSourcePos) Error() string { |
| 85 | if e.Pos.Line <= 0 || e.Pos.Col <= 0 { |
| 86 | return fmt.Sprintf("%s: %v", e.Pos.Filename, e.Underlying) |
| 87 | } |
| 88 | return fmt.Sprintf("%s:%d:%d: %v", e.Pos.Filename, e.Pos.Line, e.Pos.Col, e.Underlying) |
| 89 | } |
| 90 | |
| 91 | // GetPosition implements the ErrorWithPos interface, supplying a location in |
| 92 | // proto source that caused the error. |
| 93 | func (e ErrorWithSourcePos) GetPosition() SourcePos { |
| 94 | return *e.Pos |
| 95 | } |
| 96 | |
| 97 | // Unwrap implements the ErrorWithPos interface, supplying the underlying |
| 98 | // error. This error will not include location information. |
| 99 | func (e ErrorWithSourcePos) Unwrap() error { |
| 100 | return e.Underlying |
| 101 | } |
| 102 | |
| 103 | var _ ErrorWithPos = ErrorWithSourcePos{} |