/// extract function takes three arguments: a string slice containing the source, an index in
/// the slice for the beginning of the span and an index in the slice for the end of the span.
fn span_to_source<F>(&self, sp: Span, extract_source: F) -> Result<String, SpanSnippetError>
- where F: Fn(&str, usize, usize) -> String
+ where F: Fn(&str, usize, usize) -> Result<String, SpanSnippetError>
{
if sp.lo() > sp.hi() {
return Err(SpanSnippetError::IllFormedSpan(sp));
}
if let Some(ref src) = local_begin.sf.src {
- if !src.is_char_boundary(start_index) || !src.is_char_boundary(end_index) {
- return Err(SpanSnippetError::IllFormedSpan(sp));
- }
- return Ok(extract_source(src, start_index, end_index));
+ return extract_source(src, start_index, end_index);
} else if let Some(src) = local_begin.sf.external_src.borrow().get_source() {
- if !src.is_char_boundary(start_index) || !src.is_char_boundary(end_index) {
- return Err(SpanSnippetError::IllFormedSpan(sp));
- }
- return Ok(extract_source(src, start_index, end_index));
+ return extract_source(src, start_index, end_index);
} else {
return Err(SpanSnippetError::SourceNotAvailable {
filename: local_begin.sf.name.clone()
/// Returns the source snippet as `String` corresponding to the given `Span`
pub fn span_to_snippet(&self, sp: Span) -> Result<String, SpanSnippetError> {
- self.span_to_source(sp, |src, start_index, end_index| src[start_index..end_index]
- .to_string())
+ self.span_to_source(sp, |src, start_index, end_index| src.get(start_index..end_index)
+ .map(|s| s.to_string())
+ .ok_or_else(|| SpanSnippetError::IllFormedSpan(sp)))
}
pub fn span_to_margin(&self, sp: Span) -> Option<usize> {
/// Returns the source snippet as `String` before the given `Span`
pub fn span_to_prev_source(&self, sp: Span) -> Result<String, SpanSnippetError> {
- self.span_to_source(sp, |src, start_index, _| src[..start_index].to_string())
+ self.span_to_source(sp, |src, start_index, _| src.get(..start_index)
+ .map(|s| s.to_string())
+ .ok_or_else(|| SpanSnippetError::IllFormedSpan(sp)))
}
/// Extend the given `Span` to just after the previous occurrence of `c`. Return the same span