meli/melib/src/email/compose/mime.rs

133 lines
5.3 KiB
Rust

use super::*;
#[cfg(feature = "unicode_algorithms")]
use text_processing::grapheme_clusters::TextProcessing;
pub fn encode_header(value: &str) -> String {
let mut ret = String::with_capacity(value.len());
let mut is_current_window_ascii = true;
let mut current_window_start = 0;
#[cfg(feature = "unicode_algorithms")]
{
let graphemes = value.graphemes_indices();
for (idx, g) in graphemes {
match (g.is_ascii(), is_current_window_ascii) {
(true, true) => {
ret.push_str(g);
}
(true, false) => {
/* If !g.is_whitespace()
*
* Whitespaces inside encoded tokens must be greedily taken,
* instead of splitting each non-ascii word into separate encoded tokens. */
if !g.split_whitespace().collect::<Vec<&str>>().is_empty() {
ret.push_str(&format!(
"=?UTF-8?B?{}?=",
BASE64_MIME
.encode(value[current_window_start..idx].as_bytes())
.trim()
));
if idx != value.len() - 1 {
ret.push(' ');
}
is_current_window_ascii = true;
current_window_start = idx;
ret.push_str(g);
}
}
(false, true) => {
current_window_start = idx;
is_current_window_ascii = false;
}
/* RFC2047 recommends:
* 'While there is no limit to the length of a multiple-line header field, each line of
* a header field that contains one or more 'encoded-word's is limited to 76
* characters.'
* This is a rough compliance.
*/
(false, false) if (((4 * (idx - current_window_start) / 3) + 3) & !3) > 33 => {
ret.push_str(&format!(
"=?UTF-8?B?{}?=",
BASE64_MIME
.encode(value[current_window_start..idx].as_bytes())
.trim()
));
if idx != value.len() - 1 {
ret.push(' ');
}
current_window_start = idx;
}
(false, false) => {}
}
}
}
#[cfg(not(feature = "unicode_algorithms"))]
{
/* TODO: test this. If it works as fine as the one above, there's no need to keep the above
* implementation.*/
let mut idx = 0;
for g in value.chars() {
match (g.is_ascii(), is_current_window_ascii) {
(true, true) => {
ret.push(g);
}
(true, false) => {
/* If !g.is_whitespace()
*
* Whitespaces inside encoded tokens must be greedily taken,
* instead of splitting each non-ascii word into separate encoded tokens. */
if !g.is_whitespace() {
ret.push_str(&format!(
"=?UTF-8?B?{}?=",
BASE64_MIME
.encode(value[current_window_start..idx].as_bytes())
.trim()
));
if idx != value.len() - 1 {
ret.push(' ');
}
is_current_window_ascii = true;
current_window_start = idx;
ret.push(g);
}
}
(false, true) => {
current_window_start = idx;
is_current_window_ascii = false;
}
/* RFC2047 recommends:
* 'While there is no limit to the length of a multiple-line header field, each line of
* a header field that contains one or more 'encoded-word's is limited to 76
* characters.'
* This is a rough compliance.
*/
(false, false) if (((4 * (idx - current_window_start) / 3) + 3) & !3) > 33 => {
ret.push_str(&format!(
"=?UTF-8?B?{}?=",
BASE64_MIME
.encode(value[current_window_start..idx].as_bytes())
.trim()
));
if idx != value.len() - 1 {
ret.push(' ');
}
current_window_start = idx;
}
(false, false) => {}
}
idx += std::mem::size_of::<char>();
}
}
/* If the last part of the header value is encoded, it won't be pushed inside the previous for
* block */
if !is_current_window_ascii {
ret.push_str(&format!(
"=?UTF-8?B?{}?=",
BASE64_MIME
.encode(value[current_window_start..].as_bytes())
.trim()
));
}
ret
}