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Limit use of fields in Parsed
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This makes changing the internal representation significantly easier.
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@jhpratt
jhpratt committed Mar 13, 2022
1 parent 46bf135 commit 460b7ab
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Showing 4 changed files with 211 additions and 177 deletions.
16 changes: 4 additions & 12 deletions src/parsing/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -24,19 +24,11 @@ impl<'a, T> ParsedItem<'a, T> {
Some(ParsedItem(self.0, f(self.1)?))
}

/// Map the value to a new, optional value, preserving the remaining input.
pub(crate) fn flat_map_res<U, V>(
self,
f: impl FnOnce(T) -> Result<U, V>,
) -> Result<ParsedItem<'a, U>, V> {
Ok(ParsedItem(self.0, f(self.1)?))
}

/// Assign the stored value to the provided target. The remaining input is returned.
/// Consume the stored value with the provided function. The remaining input is returned.
#[must_use = "this returns the remaining input"]
pub(crate) fn assign_value_to(self, target: &mut Option<T>) -> &'a [u8] {
*target = Some(self.1);
self.0
pub(crate) fn consume_value(self, f: impl FnOnce(T) -> Option<()>) -> Option<&'a [u8]> {
f(self.1)?;
Some(self.0)
}
}

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161 changes: 88 additions & 73 deletions src/parsing/parsable.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -141,13 +141,13 @@ impl sealed::Sealed for Rfc2822 {
],
false,
)(input)
.ok_or(InvalidComponent("weekday"))?
.assign_value_to(&mut parsed.weekday);
.and_then(|item| item.consume_value(|value| parsed.set_weekday(value)))
.ok_or(InvalidComponent("weekday"))?;
let input = comma(input).ok_or(InvalidLiteral)?.into_inner();
let input = cfws(input).ok_or(InvalidLiteral)?.into_inner();
let input = n_to_m_digits::<_, 1, 2>(input)
.ok_or(InvalidComponent("day"))?
.assign_value_to(&mut parsed.day);
.and_then(|item| item.consume_value(|value| parsed.set_day(value)))
.ok_or(InvalidComponent("day"))?;
let input = cfws(input).ok_or(InvalidLiteral)?.into_inner();
let input = first_match(
[
Expand All @@ -166,59 +166,55 @@ impl sealed::Sealed for Rfc2822 {
],
false,
)(input)
.ok_or(InvalidComponent("month"))?
.assign_value_to(&mut parsed.month);
.and_then(|item| item.consume_value(|value| parsed.set_month(value)))
.ok_or(InvalidComponent("month"))?;
let input = cfws(input).ok_or(InvalidLiteral)?.into_inner();
let input = match exactly_n_digits::<u32, 4>(input) {
Some(item) => {
let input = item
.flat_map_res(|year| {
if year >= 1900 {
Ok(year)
} else {
Err(InvalidComponent("year"))
}
})?
.map(|year| year as _)
.assign_value_to(&mut parsed.year);
.flat_map(|year| if year >= 1900 { Some(year) } else { None })
.and_then(|item| item.consume_value(|value| parsed.set_year(value as _)))
.ok_or(InvalidComponent("year"))?;
let input = fws(input).ok_or(InvalidLiteral)?.into_inner();
input
}
None => {
let input = exactly_n_digits::<u32, 2>(input)
.ok_or(InvalidComponent("year"))?
.map(|year| if year < 50 { year + 2000 } else { year + 1900 })
.map(|year| year as _)
.assign_value_to(&mut parsed.year);
.and_then(|item| {
item.map(|year| if year < 50 { year + 2000 } else { year + 1900 })
.map(|year| year as _)
.consume_value(|value| parsed.set_year(value))
})
.ok_or(InvalidComponent("year"))?;
let input = cfws(input).ok_or(InvalidLiteral)?.into_inner();
input
}
};

let input = exactly_n_digits::<_, 2>(input)
.ok_or(InvalidComponent("hour"))?
.assign_value_to(&mut parsed.hour_24);
.and_then(|item| item.consume_value(|value| parsed.set_hour_24(value)))
.ok_or(InvalidComponent("hour"))?;
let input = opt(cfws)(input).into_inner();
let input = colon(input).ok_or(InvalidLiteral)?.into_inner();
let input = opt(cfws)(input).into_inner();
let input = exactly_n_digits::<_, 2>(input)
.ok_or(InvalidComponent("minute"))?
.assign_value_to(&mut parsed.minute);
.and_then(|item| item.consume_value(|value| parsed.set_minute(value)))
.ok_or(InvalidComponent("minute"))?;

let input = if let Some(input) = colon(opt(cfws)(input).into_inner()) {
let input = input.into_inner(); // discard the colon
let input = opt(cfws)(input).into_inner();
let input = exactly_n_digits::<_, 2>(input)
.ok_or(InvalidComponent("second"))?
.assign_value_to(&mut parsed.second);
.and_then(|item| item.consume_value(|value| parsed.set_second(value)))
.ok_or(InvalidComponent("second"))?;
let input = cfws(input).ok_or(InvalidLiteral)?.into_inner();
input
} else {
cfws(input).ok_or(InvalidLiteral)?.into_inner()
};

// The RFC explicitly allows leap seconds.
parsed.leap_second_allowed = true;
parsed.set_leap_second_allowed(true);

#[allow(clippy::unnecessary_lazy_evaluations)] // rust-lang/rust-clippy#8522
let zone_literal = first_match(
Expand All @@ -244,27 +240,36 @@ impl sealed::Sealed for Rfc2822 {
_ => None,
});
if let Some(zone_literal) = zone_literal {
let input = zone_literal.assign_value_to(&mut parsed.offset_hour);
parsed.offset_minute = Some(0);
parsed.offset_second = Some(0);
let input = zone_literal
.consume_value(|value| parsed.set_offset_hour(value))
.ok_or(InvalidComponent("offset hour"))?;
parsed
.set_offset_minute_signed(0)
.ok_or(InvalidComponent("offset minute"))?;
parsed
.set_offset_second_signed(0)
.ok_or(InvalidComponent("offset second"))?;
return Ok(input);
}

let ParsedItem(input, offset_sign) = sign(input).ok_or(InvalidComponent("offset hour"))?;
let input = exactly_n_digits::<u8, 2>(input)
.ok_or(InvalidComponent("offset hour"))?
.map(|offset_hour| {
if offset_sign == b'-' {
-(offset_hour as i8)
} else {
offset_hour as _
}
.and_then(|item| {
item.map(|offset_hour| {
if offset_sign == b'-' {
-(offset_hour as i8)
} else {
offset_hour as _
}
})
.consume_value(|value| parsed.set_offset_hour(value))
})
.assign_value_to(&mut parsed.offset_hour);
.ok_or(InvalidComponent("offset hour"))?;
let input = exactly_n_digits::<u8, 2>(input)
.ok_or(InvalidComponent("offset minute"))?
.map(|offset_minute| offset_minute as _)
.assign_value_to(&mut parsed.offset_minute);
.and_then(|item| {
item.consume_value(|value| parsed.set_offset_minute_signed(value as _))
})
.ok_or(InvalidComponent("offset minute"))?;

Ok(input)
}
Expand All @@ -284,34 +289,32 @@ impl sealed::Sealed for Rfc3339 {
let dash = ascii_char::<b'-'>;
let colon = ascii_char::<b':'>;

let input = exactly_n_digits::<_, 4>(input)
.ok_or(InvalidComponent("year"))?
.map(|year: u32| year as _)
.assign_value_to(&mut parsed.year);
let input = exactly_n_digits::<u32, 4>(input)
.and_then(|item| item.consume_value(|value| parsed.set_year(value as _)))
.ok_or(InvalidComponent("year"))?;
let input = dash(input).ok_or(InvalidLiteral)?.into_inner();
let input = exactly_n_digits::<_, 2>(input)
.ok_or(InvalidComponent("month"))?
.flat_map_res(Month::from_number)
.map_err(error::TryFromParsed::ComponentRange)?
.assign_value_to(&mut parsed.month);
.and_then(|item| item.flat_map(|value| Month::from_number(value).ok()))
.and_then(|item| item.consume_value(|value| parsed.set_month(value)))
.ok_or(InvalidComponent("month"))?;
let input = dash(input).ok_or(InvalidLiteral)?.into_inner();
let input = exactly_n_digits::<_, 2>(input)
.ok_or(InvalidComponent("day"))?
.assign_value_to(&mut parsed.day);
.and_then(|item| item.consume_value(|value| parsed.set_day(value)))
.ok_or(InvalidComponent("day"))?;
let input = ascii_char_ignore_case::<b'T'>(input)
.ok_or(InvalidLiteral)?
.into_inner();
let input = exactly_n_digits::<_, 2>(input)
.ok_or(InvalidComponent("hour"))?
.assign_value_to(&mut parsed.hour_24);
.and_then(|item| item.consume_value(|value| parsed.set_hour_24(value)))
.ok_or(InvalidComponent("hour"))?;
let input = colon(input).ok_or(InvalidLiteral)?.into_inner();
let input = exactly_n_digits::<_, 2>(input)
.ok_or(InvalidComponent("minute"))?
.assign_value_to(&mut parsed.minute);
.and_then(|item| item.consume_value(|value| parsed.set_minute(value)))
.ok_or(InvalidComponent("minute"))?;
let input = colon(input).ok_or(InvalidLiteral)?.into_inner();
let input = exactly_n_digits::<_, 2>(input)
.ok_or(InvalidComponent("second"))?
.assign_value_to(&mut parsed.second);
.and_then(|item| item.consume_value(|value| parsed.set_second(value)))
.ok_or(InvalidComponent("second"))?;
let input = if let Some(ParsedItem(input, ())) = ascii_char::<b'.'>(input) {
let ParsedItem(mut input, mut value) = any_digit(input)
.ok_or(InvalidComponent("subsecond"))?
Expand All @@ -324,37 +327,49 @@ impl sealed::Sealed for Rfc3339 {
multiplier /= 10;
}

ParsedItem(input, value).assign_value_to(&mut parsed.subsecond)
parsed
.set_subsecond(value)
.ok_or(InvalidComponent("subsecond"))?;
input
} else {
input
};

// The RFC explicitly allows leap seconds.
parsed.leap_second_allowed = true;
parsed.set_leap_second_allowed(true);

if let Some(ParsedItem(input, ())) = ascii_char_ignore_case::<b'Z'>(input) {
parsed.offset_hour = Some(0);
parsed.offset_minute = Some(0);
parsed.offset_second = Some(0);
parsed
.set_offset_hour(0)
.ok_or(InvalidComponent("offset hour"))?;
parsed
.set_offset_minute_signed(0)
.ok_or(InvalidComponent("offset minute"))?;
parsed
.set_offset_second_signed(0)
.ok_or(InvalidComponent("offset second"))?;
return Ok(input);
}

let ParsedItem(input, offset_sign) = sign(input).ok_or(InvalidComponent("offset hour"))?;
let input = exactly_n_digits::<_, 2>(input)
.ok_or(InvalidComponent("offset hour"))?
.map(|offset_hour: u8| {
if offset_sign == b'-' {
-(offset_hour as i8)
} else {
offset_hour as _
}
let input = exactly_n_digits::<u8, 2>(input)
.and_then(|item| {
item.map(|offset_hour| {
if offset_sign == b'-' {
-(offset_hour as i8)
} else {
offset_hour as _
}
})
.consume_value(|value| parsed.set_offset_hour(value))
})
.assign_value_to(&mut parsed.offset_hour);
.ok_or(InvalidComponent("offset hour"))?;
let input = colon(input).ok_or(InvalidLiteral)?.into_inner();
let input = exactly_n_digits::<u8, 2>(input)
.ok_or(InvalidComponent("offset minute"))?
.map(|offset_minute: u8| offset_minute as _)
.assign_value_to(&mut parsed.offset_minute);
.and_then(|item| {
item.consume_value(|value| parsed.set_offset_minute_signed(value as _))
})
.ok_or(InvalidComponent("offset minute"))?;

Ok(input)
}
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