// Init prepares the scanner S to tokenize the text src by setting the
// scanner at the beginning of src. The scanner uses the file set file
// for position information and it adds line information for each line.
// It is ok to re-use the same file when re-scanning the same file as
// line information which is already present is ignored. Init causes a
// panic if the file size does not match the src size.
//
// Calls to Scan will use the error handler err if they encounter a
// syntax error and err is not nil. Also, for each error encountered,
// the Scanner field ErrorCount is incremented by one. The mode parameter
// determines how comments, illegal characters, and semicolons are handled.
//
// Note that Init may call err if there is an error in the first character
// of the file.
//
func (S *Scanner) Init(file *token.File, src []byte, err ErrorHandler, mode uint) {
// Explicitly initialize all fields since a scanner may be reused.
if file.Size() != len(src) {
panic("file size does not match src len")
}
S.file = file
S.dir, _ = filepath.Split(file.Name())
S.src = src
S.err = err
S.mode = mode
S.ch = ' '
S.offset = 0
S.rdOffset = 0
S.lineOffset = 0
S.runeColumn = 0
S.insertSemi = false
S.ErrorCount = 0
S.prevState.Offset = -1 // declare previous scanning state invalid. Can't call prev() at first or repeatedly.
file.SetLinesForContent(src) // calculate line-end positions.
S.Next()
}
/*
Stores the file name and source line position info into the ast.File in a form that can
be persisted with the ast.File when it is GOB-serialized into a .rlc file.
*/
func (f *File) StoreSourceFilePositionInfo(file *token.File) {
f.FileName = file.Name()
f.FileSize = file.Size()
f.FileLines = file.Lines()
}