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use std::fmt;
use std::iter::FromIterator;
use std::marker::PhantomData;
use bytes::BytesMut;
use util::TryFromValues;
use HeaderValue;
// A single `HeaderValue` that can flatten multiple values with commas.
#[derive(Clone, PartialEq, Eq, Hash)]
pub(crate) struct FlatCsv<Sep = Comma> {
pub(crate) value: HeaderValue,
_marker: PhantomData<Sep>,
}
pub(crate) trait Separator {
const BYTE: u8;
const CHAR: char;
}
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub(crate) enum Comma {}
impl Separator for Comma {
const BYTE: u8 = b',';
const CHAR: char = ',';
}
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub(crate) enum SemiColon {}
impl Separator for SemiColon {
const BYTE: u8 = b';';
const CHAR: char = ';';
}
impl<Sep: Separator> FlatCsv<Sep> {
pub(crate) fn iter(&self) -> impl Iterator<Item = &str> {
self.value.to_str().ok().into_iter().flat_map(|value_str| {
let mut in_quotes = false;
value_str
.split(move |c| {
if in_quotes {
if c == '"' {
in_quotes = false;
}
false // dont split
} else {
if c == Sep::CHAR {
true // split
} else {
if c == '"' {
in_quotes = true;
}
false // dont split
}
}
})
.map(|item| item.trim())
})
}
}
impl<Sep: Separator> TryFromValues for FlatCsv<Sep> {
fn try_from_values<'i, I>(values: &mut I) -> Result<Self, ::Error>
where
I: Iterator<Item = &'i HeaderValue>,
{
let flat = values.collect();
Ok(flat)
}
}
impl<Sep> From<HeaderValue> for FlatCsv<Sep> {
fn from(value: HeaderValue) -> Self {
FlatCsv {
value,
_marker: PhantomData,
}
}
}
impl<'a, Sep> From<&'a FlatCsv<Sep>> for HeaderValue {
fn from(flat: &'a FlatCsv<Sep>) -> HeaderValue {
flat.value.clone()
}
}
impl<Sep> fmt::Debug for FlatCsv<Sep> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
fmt::Debug::fmt(&self.value, f)
}
}
impl<'a, Sep: Separator> FromIterator<&'a HeaderValue> for FlatCsv<Sep> {
fn from_iter<I>(iter: I) -> Self
where
I: IntoIterator<Item = &'a HeaderValue>,
{
let mut values = iter.into_iter();
// Common case is there is only 1 value, optimize for that
if let (1, Some(1)) = values.size_hint() {
return values
.next()
.expect("size_hint claimed 1 item")
.clone()
.into();
}
// Otherwise, there are multiple, so this should merge them into 1.
let mut buf = values
.next()
.cloned()
.map(|val| BytesMut::from(val.as_bytes()))
.unwrap_or_else(|| BytesMut::new());
for val in values {
buf.extend_from_slice(&[Sep::BYTE, b' ']);
buf.extend_from_slice(val.as_bytes());
}
let val = HeaderValue::from_maybe_shared(buf.freeze())
.expect("comma separated HeaderValues are valid");
val.into()
}
}
// TODO: would be great if there was a way to de-dupe these with above
impl<Sep: Separator> FromIterator<HeaderValue> for FlatCsv<Sep> {
fn from_iter<I>(iter: I) -> Self
where
I: IntoIterator<Item = HeaderValue>,
{
let mut values = iter.into_iter();
// Common case is there is only 1 value, optimize for that
if let (1, Some(1)) = values.size_hint() {
return values.next().expect("size_hint claimed 1 item").into();
}
// Otherwise, there are multiple, so this should merge them into 1.
let mut buf = values
.next()
.map(|val| BytesMut::from(val.as_bytes()))
.unwrap_or_else(|| BytesMut::new());
for val in values {
buf.extend_from_slice(&[Sep::BYTE, b' ']);
buf.extend_from_slice(val.as_bytes());
}
let val = HeaderValue::from_maybe_shared(buf.freeze())
.expect("comma separated HeaderValues are valid");
val.into()
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn comma() {
let val = HeaderValue::from_static("aaa, b; bb, ccc");
let csv = FlatCsv::<Comma>::from(val);
let mut values = csv.iter();
assert_eq!(values.next(), Some("aaa"));
assert_eq!(values.next(), Some("b; bb"));
assert_eq!(values.next(), Some("ccc"));
assert_eq!(values.next(), None);
}
#[test]
fn semicolon() {
let val = HeaderValue::from_static("aaa; b, bb; ccc");
let csv = FlatCsv::<SemiColon>::from(val);
let mut values = csv.iter();
assert_eq!(values.next(), Some("aaa"));
assert_eq!(values.next(), Some("b, bb"));
assert_eq!(values.next(), Some("ccc"));
assert_eq!(values.next(), None);
}
#[test]
fn quoted_text() {
let val = HeaderValue::from_static("foo=\"bar,baz\", sherlock=holmes");
let csv = FlatCsv::<Comma>::from(val);
let mut values = csv.iter();
assert_eq!(values.next(), Some("foo=\"bar,baz\""));
assert_eq!(values.next(), Some("sherlock=holmes"));
assert_eq!(values.next(), None);
}
}