deltachat/
tools.rs

1//! Some tools and enhancements to the used libraries, there should be
2//! no references to Context and other "larger" entities here.
3
4#![allow(missing_docs)]
5
6use std::borrow::Cow;
7use std::io::{Cursor, Write};
8use std::mem;
9use std::ops::{AddAssign, Deref};
10use std::path::{Path, PathBuf};
11use std::str::from_utf8;
12// If a time value doesn't need to be sent to another host, saved to the db or otherwise used across
13// program restarts, a monotonically nondecreasing clock (`Instant`) should be used. But as
14// `Instant` may use `libc::clock_gettime(CLOCK_MONOTONIC)`, e.g. on Android, and does not advance
15// while being in deep sleep mode, we use `SystemTime` instead, but add an alias for it to document
16// why `Instant` isn't used in those places. Also this can help to switch to another clock impl if
17// we find any. Another reason is that `Instant` may reintroduce panics in the future versions:
18// https://doc.rust-lang.org/1.87.0/std/time/struct.Instant.html#method.elapsed.
19use std::time::Duration;
20pub use std::time::SystemTime as Time;
21#[cfg(not(test))]
22pub use std::time::SystemTime;
23
24use anyhow::{Context as _, Result, bail, ensure};
25use base64::Engine as _;
26use chrono::{Local, NaiveDateTime, NaiveTime, TimeZone};
27use deltachat_contact_tools::EmailAddress;
28#[cfg(test)]
29pub use deltachat_time::SystemTimeTools as SystemTime;
30use futures::TryStreamExt;
31use mailparse::MailHeaderMap;
32use mailparse::dateparse;
33use mailparse::headers::Headers;
34use num_traits::PrimInt;
35use tokio::{fs, io};
36use url::Url;
37use uuid::Uuid;
38
39use crate::chat::{add_device_msg, add_device_msg_with_importance};
40use crate::config::Config;
41use crate::constants::{self, DC_ELLIPSIS, DC_OUTDATED_WARNING_DAYS};
42use crate::context::Context;
43use crate::events::EventType;
44use crate::log::warn;
45use crate::message::{Message, Viewtype};
46use crate::stock_str;
47
48/// Shortens a string to a specified length and adds "[...]" to the
49/// end of the shortened string.
50#[expect(clippy::arithmetic_side_effects)]
51pub(crate) fn truncate(buf: &str, approx_chars: usize) -> Cow<'_, str> {
52    let count = buf.chars().count();
53    if count <= approx_chars + DC_ELLIPSIS.len() {
54        return Cow::Borrowed(buf);
55    }
56    let end_pos = buf
57        .char_indices()
58        .nth(approx_chars)
59        .map(|(n, _)| n)
60        .unwrap_or_default();
61
62    if let Some(index) = buf.get(..end_pos).and_then(|s| s.rfind([' ', '\n'])) {
63        Cow::Owned(format!(
64            "{}{}",
65            &buf.get(..=index).unwrap_or_default(),
66            DC_ELLIPSIS
67        ))
68    } else {
69        Cow::Owned(format!(
70            "{}{}",
71            &buf.get(..end_pos).unwrap_or_default(),
72            DC_ELLIPSIS
73        ))
74    }
75}
76
77/// Shortens a string to a specified line count and adds "[...]" to the
78/// end of the shortened string.
79///
80/// returns tuple with the String and a boolean whether is was truncated
81#[expect(clippy::arithmetic_side_effects)]
82pub(crate) fn truncate_by_lines(
83    buf: String,
84    max_lines: usize,
85    max_line_len: usize,
86) -> (String, bool) {
87    let mut lines = 0;
88    let mut line_chars = 0;
89    let mut break_point: Option<usize> = None;
90
91    for (index, char) in buf.char_indices() {
92        if char == '\n' {
93            line_chars = 0;
94            lines += 1;
95        } else {
96            line_chars += 1;
97            if line_chars > max_line_len {
98                line_chars = 1;
99                lines += 1;
100            }
101        }
102        if lines == max_lines {
103            break_point = Some(index);
104            break;
105        }
106    }
107
108    if let Some(end_pos) = break_point {
109        // Text has too many lines and needs to be truncated.
110        let text = {
111            if let Some(buffer) = buf.get(..end_pos) {
112                if let Some(index) = buffer.rfind([' ', '\n']) {
113                    buf.get(..=index)
114                } else {
115                    buf.get(..end_pos)
116                }
117            } else {
118                None
119            }
120        };
121
122        if let Some(truncated_text) = text {
123            (format!("{truncated_text}{DC_ELLIPSIS}"), true)
124        } else {
125            // In case of indexing/slicing error, we return an error
126            // message as a preview and add HTML version. This should
127            // never happen.
128            let error_text = "[Truncation of the message failed, this is a bug in the Delta Chat core. Please report it.\nYou can still open the full text to view the original message.]";
129            (error_text.to_string(), true)
130        }
131    } else {
132        // text is unchanged
133        (buf, false)
134    }
135}
136
137/// Shortens a message text if necessary according to the configuration. Adds "[...]" to the end of
138/// the shortened text.
139///
140/// Returns the resulting text and a bool telling whether a truncation was done.
141pub(crate) async fn truncate_msg_text(context: &Context, text: String) -> Result<(String, bool)> {
142    if context.get_config_bool(Config::Bot).await? {
143        return Ok((text, false));
144    }
145    // Truncate text if it has too many lines
146    Ok(truncate_by_lines(
147        text,
148        constants::DC_DESIRED_TEXT_LINES,
149        constants::DC_DESIRED_TEXT_LINE_LEN,
150    ))
151}
152
153/* ******************************************************************************
154 * date/time tools
155 ******************************************************************************/
156
157/// Converts Unix time in seconds to a local timestamp string.
158pub fn timestamp_to_str(wanted: i64) -> String {
159    if let Some(ts) = Local.timestamp_opt(wanted, 0).single() {
160        ts.format("%Y.%m.%d %H:%M:%S").to_string()
161    } else {
162        // Out of range number of seconds.
163        "??.??.?? ??:??:??".to_string()
164    }
165}
166
167/// Converts duration to string representation suitable for logs.
168pub fn duration_to_str(duration: Duration) -> String {
169    let secs = duration.as_secs();
170    let h = secs / 3600;
171    let m = (secs % 3600) / 60;
172    let s = (secs % 3600) % 60;
173    format!("{h}h {m}m {s}s")
174}
175
176pub(crate) fn gm2local_offset() -> i64 {
177    /* returns the offset that must be _added_ to an UTC/GMT-time to create the localtime.
178    the function may return negative values. */
179    let lt = Local::now();
180    i64::from(lt.offset().local_minus_utc())
181}
182
183/// Returns the current smeared timestamp,
184///
185/// The returned timestamp MAY NOT be unique and MUST NOT go to "Date" header.
186pub(crate) fn smeared_time(context: &Context) -> i64 {
187    let now = time();
188    let ts = context.smeared_timestamp.current();
189    std::cmp::max(ts, now)
190}
191
192/// Returns a timestamp that is guaranteed to be unique.
193pub(crate) fn create_smeared_timestamp(context: &Context) -> i64 {
194    let now = time();
195    context.smeared_timestamp.create(now)
196}
197
198// creates `count` timestamps that are guaranteed to be unique.
199// the first created timestamps is returned directly,
200// get the other timestamps just by adding 1..count-1
201pub(crate) fn create_smeared_timestamps(context: &Context, count: usize) -> i64 {
202    let now = time();
203    context.smeared_timestamp.create_n(now, count as i64)
204}
205
206/// Returns the last release timestamp as a unix timestamp compatible for comparison with time() and
207/// database times.
208pub fn get_release_timestamp() -> i64 {
209    NaiveDateTime::new(
210        *crate::release::DATE,
211        NaiveTime::from_hms_opt(0, 0, 0).unwrap(),
212    )
213    .and_utc()
214    .timestamp_millis()
215        / 1_000
216}
217
218// if the system time is not plausible, once a day, add a device message.
219// for testing we're using time() as that is also used for message timestamps.
220// moreover, add a warning if the app is outdated.
221pub(crate) async fn maybe_add_time_based_warnings(context: &Context) {
222    if !maybe_warn_on_bad_time(context, time(), get_release_timestamp()).await {
223        maybe_warn_on_outdated(context, time(), get_release_timestamp()).await;
224    }
225}
226
227async fn maybe_warn_on_bad_time(context: &Context, now: i64, known_past_timestamp: i64) -> bool {
228    if now < known_past_timestamp {
229        let mut msg = Message::new(Viewtype::Text);
230        msg.text = stock_str::bad_time_msg_body(
231            context,
232            &Local.timestamp_opt(now, 0).single().map_or_else(
233                || "YY-MM-DD hh:mm:ss".to_string(),
234                |ts| ts.format("%Y-%m-%d %H:%M:%S").to_string(),
235            ),
236        );
237        if let Some(timestamp) = chrono::DateTime::<chrono::Utc>::from_timestamp(now, 0) {
238            add_device_msg_with_importance(
239                context,
240                Some(
241                    format!(
242                        "bad-time-warning-{}",
243                        timestamp.format("%Y-%m-%d") // repeat every day
244                    )
245                    .as_str(),
246                ),
247                Some(&mut msg),
248                true,
249            )
250            .await
251            .ok();
252        } else {
253            warn!(context, "Can't convert current timestamp");
254        }
255        return true;
256    }
257    false
258}
259
260#[expect(clippy::arithmetic_side_effects)]
261async fn maybe_warn_on_outdated(context: &Context, now: i64, approx_compile_time: i64) {
262    if now > approx_compile_time + DC_OUTDATED_WARNING_DAYS * 24 * 60 * 60 {
263        let mut msg = Message::new_text(stock_str::update_reminder_msg_body(context));
264        if let Some(timestamp) = chrono::DateTime::<chrono::Utc>::from_timestamp(now, 0) {
265            add_device_msg(
266                context,
267                Some(
268                    format!(
269                        "outdated-warning-{}",
270                        timestamp.format("%Y-%m") // repeat every month
271                    )
272                    .as_str(),
273                ),
274                Some(&mut msg),
275            )
276            .await
277            .ok();
278        }
279    }
280}
281
282/// Generate an unique ID.
283///
284/// The generated ID should be short but unique:
285/// - short, because it used in Chat-Group-ID headers and in QR codes
286/// - unique as two IDs generated on two devices should not be the same
287///
288/// IDs generated by this function have 144 bits of entropy
289/// and are returned as 24 Base64 characters, each containing 6 bits of entropy.
290/// 144 is chosen because it is sufficiently secure
291/// (larger than AES-128 keys used for message encryption)
292/// and divides both by 8 (byte size) and 6 (number of bits in a single Base64 character).
293pub(crate) fn create_id() -> String {
294    // Generate 144 random bits.
295    let mut arr = [0u8; 18];
296    rand::fill(&mut arr[..]);
297
298    base64::engine::general_purpose::URL_SAFE.encode(arr)
299}
300
301/// Generate a shared secret for a broadcast channel, consisting of 43 characters.
302///
303/// The string generated by this function has 258 bits of entropy
304/// and is returned as 43 Base64 characters, each containing 6 bits of entropy.
305/// 258 is chosen because we may switch to AES-256 keys in the future,
306/// and so that the shared secret definitely won't be the weak spot.
307pub(crate) fn create_broadcast_secret() -> String {
308    // ThreadRng implements CryptoRng trait and is supposed to be cryptographically secure.
309    // Generate 264 random bits.
310    let mut arr = [0u8; 33];
311    rand::fill(&mut arr[..]);
312
313    let mut res = base64::engine::general_purpose::URL_SAFE.encode(arr);
314    res.truncate(43);
315    res
316}
317
318/// Returns true if given string is a valid ID.
319///
320/// All IDs generated with `create_id()` should be considered valid.
321pub(crate) fn validate_id(s: &str) -> bool {
322    let alphabet = base64::alphabet::URL_SAFE.as_str();
323    s.chars().all(|c| alphabet.contains(c)) && s.len() > 10 && s.len() <= 32
324}
325
326pub(crate) fn validate_broadcast_secret(s: &str) -> bool {
327    let alphabet = base64::alphabet::URL_SAFE.as_str();
328    s.chars().all(|c| alphabet.contains(c)) && s.len() >= 43 && s.len() <= 100
329}
330
331/// Function generates a Message-ID that can be used for a new outgoing message.
332/// - this function is called for all outgoing messages.
333/// - the message ID should be globally unique
334/// - do not add a counter or any private data as this leaks information unnecessarily
335pub(crate) fn create_outgoing_rfc724_mid() -> String {
336    // We use UUID similarly to iCloud web mail client
337    // because it seems their spam filter does not like Message-IDs
338    // without hyphens.
339    //
340    // However, we use `localhost` instead of the real domain to avoid
341    // leaking the domain when resent by otherwise anonymizing
342    // From-rewriting mailing lists and forwarders.
343    let uuid = Uuid::new_v4();
344    format!("{uuid}@localhost")
345}
346
347// the returned suffix is lower-case
348pub fn get_filesuffix_lc(path_filename: &str) -> Option<String> {
349    Path::new(path_filename)
350        .extension()
351        .map(|p| p.to_string_lossy().to_lowercase())
352}
353
354/// Returns the `(width, height)` of the given image buffer.
355pub fn get_filemeta(buf: &[u8]) -> Result<(u32, u32)> {
356    let image = image::ImageReader::new(Cursor::new(buf)).with_guessed_format()?;
357    let dimensions = image.into_dimensions()?;
358    Ok(dimensions)
359}
360
361/// Expand paths relative to $BLOBDIR into absolute paths.
362///
363/// If `path` starts with "$BLOBDIR", replaces it with the blobdir path.
364/// Otherwise, returns path as is.
365pub(crate) fn get_abs_path(context: &Context, path: &Path) -> PathBuf {
366    if let Ok(p) = path.strip_prefix("$BLOBDIR") {
367        context.get_blobdir().join(p)
368    } else {
369        path.into()
370    }
371}
372
373pub(crate) async fn get_filebytes(context: &Context, path: &Path) -> Result<u64> {
374    let path_abs = get_abs_path(context, path);
375    let meta = fs::metadata(&path_abs).await?;
376    Ok(meta.len())
377}
378
379pub(crate) async fn delete_file(context: &Context, path: &Path) -> Result<()> {
380    let path_abs = get_abs_path(context, path);
381    if !path_abs.exists() {
382        bail!("path {} does not exist", path_abs.display());
383    }
384    if !path_abs.is_file() {
385        warn!(context, "refusing to delete non-file {}.", path.display());
386        bail!("not a file: \"{}\"", path.display());
387    }
388
389    let dpath = format!("{}", path.to_string_lossy());
390    fs::remove_file(path_abs)
391        .await
392        .with_context(|| format!("cannot delete {dpath:?}"))?;
393    context.emit_event(EventType::DeletedBlobFile(dpath));
394    Ok(())
395}
396
397/// Create a safe name based on a messy input string.
398///
399/// The safe name will be a valid filename on Unix and Windows and
400/// not contain any path separators.  The input can contain path
401/// segments separated by either Unix or Windows path separators,
402/// the rightmost non-empty segment will be used as name,
403/// sanitised for special characters.
404pub(crate) fn sanitize_filename(mut name: &str) -> String {
405    for part in name.rsplit('/') {
406        if !part.is_empty() {
407            name = part;
408            break;
409        }
410    }
411    for part in name.rsplit('\\') {
412        if !part.is_empty() {
413            name = part;
414            break;
415        }
416    }
417
418    let opts = sanitize_filename::Options {
419        truncate: true,
420        windows: true,
421        replacement: "",
422    };
423    let name = sanitize_filename::sanitize_with_options(name, opts);
424
425    if name.starts_with('.') || name.is_empty() {
426        format!("file{name}")
427    } else {
428        name
429    }
430}
431
432/// A guard which will remove the path when dropped.
433///
434/// It implements [`Deref`] so it can be used as a `&Path`.
435#[derive(Debug)]
436pub(crate) struct TempPathGuard {
437    path: PathBuf,
438}
439
440impl TempPathGuard {
441    pub(crate) fn new(path: PathBuf) -> Self {
442        Self { path }
443    }
444}
445
446impl Drop for TempPathGuard {
447    fn drop(&mut self) {
448        let path = self.path.clone();
449        std::fs::remove_file(path).ok();
450    }
451}
452
453impl Deref for TempPathGuard {
454    type Target = Path;
455
456    fn deref(&self) -> &Self::Target {
457        &self.path
458    }
459}
460
461impl AsRef<Path> for TempPathGuard {
462    fn as_ref(&self) -> &Path {
463        self
464    }
465}
466
467pub(crate) async fn create_folder(context: &Context, path: &Path) -> Result<(), io::Error> {
468    let path_abs = get_abs_path(context, path);
469    if !path_abs.exists() {
470        match fs::create_dir_all(path_abs).await {
471            Ok(_) => Ok(()),
472            Err(err) => {
473                warn!(
474                    context,
475                    "Cannot create directory \"{}\": {}",
476                    path.display(),
477                    err
478                );
479                Err(err)
480            }
481        }
482    } else {
483        Ok(())
484    }
485}
486
487/// Write a the given content to provided file path.
488pub(crate) async fn write_file(
489    context: &Context,
490    path: &Path,
491    buf: &[u8],
492) -> Result<(), io::Error> {
493    let path_abs = get_abs_path(context, path);
494    fs::write(&path_abs, buf).await.map_err(|err| {
495        warn!(
496            context,
497            "Cannot write {} bytes to \"{}\": {}",
498            buf.len(),
499            path.display(),
500            err
501        );
502        err
503    })
504}
505
506/// Reads the file and returns its context as a byte vector.
507pub async fn read_file(context: &Context, path: &Path) -> Result<Vec<u8>> {
508    let path_abs = get_abs_path(context, path);
509
510    match fs::read(&path_abs).await {
511        Ok(bytes) => Ok(bytes),
512        Err(err) => {
513            warn!(
514                context,
515                "Cannot read \"{}\" or file is empty: {}",
516                path.display(),
517                err
518            );
519            Err(err.into())
520        }
521    }
522}
523
524pub async fn open_file(context: &Context, path: &Path) -> Result<fs::File> {
525    let path_abs = get_abs_path(context, path);
526
527    match fs::File::open(&path_abs).await {
528        Ok(bytes) => Ok(bytes),
529        Err(err) => {
530            warn!(
531                context,
532                "Cannot read \"{}\" or file is empty: {}",
533                path.display(),
534                err
535            );
536            Err(err.into())
537        }
538    }
539}
540
541pub fn open_file_std(context: &Context, path: impl AsRef<Path>) -> Result<std::fs::File> {
542    let path_abs = get_abs_path(context, path.as_ref());
543
544    match std::fs::File::open(path_abs) {
545        Ok(bytes) => Ok(bytes),
546        Err(err) => {
547            warn!(
548                context,
549                "Cannot read \"{}\" or file is empty: {}",
550                path.as_ref().display(),
551                err
552            );
553            Err(err.into())
554        }
555    }
556}
557
558/// Reads directory and returns a vector of directory entries.
559pub async fn read_dir(path: &Path) -> Result<Vec<fs::DirEntry>> {
560    let res = tokio_stream::wrappers::ReadDirStream::new(fs::read_dir(path).await?)
561        .try_collect()
562        .await?;
563    Ok(res)
564}
565
566pub(crate) fn time() -> i64 {
567    SystemTime::now()
568        .duration_since(SystemTime::UNIX_EPOCH)
569        .unwrap_or_default()
570        .as_secs() as i64
571}
572
573pub(crate) fn time_elapsed(time: &Time) -> Duration {
574    time.elapsed().unwrap_or_default()
575}
576
577/// Struct containing all mailto information
578#[derive(Debug, Default, Eq, PartialEq)]
579pub struct MailTo {
580    pub to: Vec<EmailAddress>,
581    pub subject: Option<String>,
582    pub body: Option<String>,
583}
584
585/// Parse mailto urls
586pub fn parse_mailto(mailto_url: &str) -> Option<MailTo> {
587    if let Ok(url) = Url::parse(mailto_url) {
588        if url.scheme() == "mailto" {
589            let mut mailto: MailTo = Default::default();
590            // Extract the email address
591            url.path().split(',').for_each(|email| {
592                if let Ok(email) = EmailAddress::new(email) {
593                    mailto.to.push(email);
594                }
595            });
596
597            // Extract query parameters
598            for (key, value) in url.query_pairs() {
599                if key == "subject" {
600                    mailto.subject = Some(value.to_string());
601                } else if key == "body" {
602                    mailto.body = Some(value.to_string());
603                }
604            }
605            Some(mailto)
606        } else {
607            None
608        }
609    } else {
610        None
611    }
612}
613
614pub(crate) trait IsNoneOrEmpty<T> {
615    /// Returns true if an Option does not contain a string
616    /// or contains an empty string.
617    fn is_none_or_empty(&self) -> bool;
618}
619impl<T> IsNoneOrEmpty<T> for Option<T>
620where
621    T: AsRef<str>,
622{
623    fn is_none_or_empty(&self) -> bool {
624        !matches!(self, Some(s) if !s.as_ref().is_empty())
625    }
626}
627
628pub(crate) trait ToOption<T> {
629    fn to_option(self) -> Option<T>;
630}
631impl<'a> ToOption<&'a str> for &'a String {
632    fn to_option(self) -> Option<&'a str> {
633        if self.is_empty() { None } else { Some(self) }
634    }
635}
636impl ToOption<String> for u16 {
637    fn to_option(self) -> Option<String> {
638        if self == 0 {
639            None
640        } else {
641            Some(self.to_string())
642        }
643    }
644}
645impl ToOption<String> for Option<i32> {
646    fn to_option(self) -> Option<String> {
647        match self {
648            None | Some(0) => None,
649            Some(v) => Some(v.to_string()),
650        }
651    }
652}
653
654#[expect(clippy::arithmetic_side_effects)]
655pub fn remove_subject_prefix(last_subject: &str) -> String {
656    let subject_start = if last_subject.starts_with("Chat:") {
657        0
658    } else {
659        // "Antw:" is the longest abbreviation in
660        // <https://en.wikipedia.org/wiki/List_of_email_subject_abbreviations#Abbreviations_in_other_languages>,
661        // so look at the first _5_ characters:
662        match last_subject.chars().take(5).position(|c| c == ':') {
663            Some(prefix_end) => prefix_end + 1,
664            None => 0,
665        }
666    };
667    last_subject
668        .chars()
669        .skip(subject_start)
670        .collect::<String>()
671        .trim()
672        .to_string()
673}
674
675// Types and methods to create hop-info for message-info
676
677#[expect(clippy::arithmetic_side_effects)]
678fn extract_address_from_receive_header<'a>(header: &'a str, start: &str) -> Option<&'a str> {
679    let header_len = header.len();
680    header.find(start).and_then(|mut begin| {
681        begin += start.len();
682        let end = header
683            .get(begin..)?
684            .find(|c: char| c.is_whitespace())
685            .unwrap_or(header_len);
686        header.get(begin..begin + end)
687    })
688}
689
690#[expect(clippy::arithmetic_side_effects)]
691pub(crate) fn parse_receive_header(header: &str) -> String {
692    let header = header.replace(&['\r', '\n'][..], "");
693    let mut hop_info = String::from("Hop: ");
694
695    if let Some(from) = extract_address_from_receive_header(&header, "from ") {
696        hop_info += &format!("From: {}; ", from.trim());
697    }
698
699    if let Some(by) = extract_address_from_receive_header(&header, "by ") {
700        hop_info += &format!("By: {}; ", by.trim());
701    }
702
703    if let Ok(date) = dateparse(&header) {
704        // In tests, use the UTC timezone so that the test is reproducible
705        #[cfg(test)]
706        let date_obj = chrono::Utc.timestamp_opt(date, 0).single();
707        #[cfg(not(test))]
708        let date_obj = Local.timestamp_opt(date, 0).single();
709
710        hop_info += &format!(
711            "Date: {}",
712            date_obj.map_or_else(|| "?".to_string(), |x| x.to_rfc2822())
713        );
714    };
715
716    hop_info
717}
718
719/// parses "receive"-headers
720pub(crate) fn parse_receive_headers(headers: &Headers) -> String {
721    headers
722        .get_all_headers("Received")
723        .iter()
724        .rev()
725        .filter_map(|header_map_item| from_utf8(header_map_item.get_value_raw()).ok())
726        .map(parse_receive_header)
727        .collect::<Vec<_>>()
728        .join("\n")
729}
730
731/// If `collection` contains exactly one element, return this element.
732/// Otherwise, return None.
733pub(crate) fn single_value<T>(collection: impl IntoIterator<Item = T>) -> Option<T> {
734    let mut iter = collection.into_iter();
735    if let Some(value) = iter.next()
736        && iter.next().is_none()
737    {
738        return Some(value);
739    }
740    None
741}
742
743/// Compressor/decompressor buffer size.
744const BROTLI_BUFSZ: usize = 4096;
745
746/// Compresses `buf` to `Vec` using `brotli`.
747/// Note that it handles an empty `buf` as a special value that remains empty after compression,
748/// otherwise brotli would add its metadata to it which is not nice because this function is used
749/// for compression of strings stored in the db and empty strings are common there. This approach is
750/// not strictly correct because nowhere in the brotli documentation is said that an empty buffer
751/// can't be a result of compression of some input, but i think this will never break.
752pub(crate) fn buf_compress(buf: &[u8]) -> Result<Vec<u8>> {
753    if buf.is_empty() {
754        return Ok(Vec::new());
755    }
756    // level 4 is 2x faster than level 6 (and 54x faster than 10, for comparison).
757    // with the adaptiveness, we aim to not slow down processing
758    // single large files too much, esp. on low-budget devices.
759    // in tests (see #4129), this makes a difference, without compressing much worse.
760    let q: u32 = if buf.len() > 1_000_000 { 4 } else { 6 };
761    let lgwin: u32 = 22; // log2(LZ77 window size), it's the default for brotli CLI tool.
762    let mut compressor = brotli::CompressorWriter::new(Vec::new(), BROTLI_BUFSZ, q, lgwin);
763    compressor.write_all(buf)?;
764    Ok(compressor.into_inner())
765}
766
767/// Decompresses `buf` to `Vec` using `brotli`.
768/// See `buf_compress()` for why we don't pass an empty buffer to brotli decompressor.
769pub(crate) fn buf_decompress(buf: &[u8]) -> Result<Vec<u8>> {
770    if buf.is_empty() {
771        return Ok(Vec::new());
772    }
773    let mut decompressor = brotli::DecompressorWriter::new(Vec::new(), BROTLI_BUFSZ);
774    decompressor.write_all(buf)?;
775    decompressor.flush()?;
776    Ok(mem::take(decompressor.get_mut()))
777}
778
779/// Returns the given `&str` if already lowercased to avoid allocation, otherwise lowercases it.
780pub(crate) fn to_lowercase(s: &str) -> Cow<'_, str> {
781    match s.chars().all(char::is_lowercase) {
782        true => Cow::Borrowed(s),
783        false => Cow::Owned(s.to_lowercase()),
784    }
785}
786
787/// Returns text for storing in special db columns to make case-insensitive search possible for
788/// non-ASCII messages, chat and contact names.
789pub(crate) fn normalize_text(text: &str) -> Option<String> {
790    if text.is_ascii() {
791        return None;
792    };
793    Some(text.to_lowercase()).filter(|t| t != text)
794}
795
796/// Increments `*t` and checks that it equals to `expected` after that.
797#[expect(clippy::arithmetic_side_effects)]
798pub(crate) fn inc_and_check<T: PrimInt + AddAssign + std::fmt::Debug>(
799    t: &mut T,
800    expected: T,
801) -> Result<()> {
802    *t += T::one();
803    ensure!(*t == expected, "Incremented value != {expected:?}");
804    Ok(())
805}
806
807/// Converts usize to u64 without using `as`.
808///
809/// This is needed for example to convert in-memory buffer sizes
810/// to u64 type used for counting all the bytes written.
811///
812/// On 32-bit systems it is possible to have files
813/// larger than 4 GiB or write more than 4 GiB to network connection,
814/// in which case we need a 64-bit total counter,
815/// but use 32-bit usize for buffer sizes.
816///
817/// This can only break if usize has more than 64 bits
818/// and this is not the case as of 2025 and is
819/// unlikely to change for general purpose computers.
820/// See <https://github.com/rust-lang/rust/issues/30495>
821/// and <https://users.rust-lang.org/t/cant-convert-usize-to-u64/6243>
822/// and <https://github.com/rust-lang/rust/issues/106050>.
823pub(crate) fn usize_to_u64(v: usize) -> u64 {
824    u64::try_from(v).unwrap_or(u64::MAX)
825}
826
827/// Returns early with an error if a condition is not satisfied.
828/// In non-optimized builds, panics instead if so.
829#[macro_export]
830macro_rules! ensure_and_debug_assert {
831    ($cond:expr, $($arg:tt)*) => {
832        let cond_val = $cond;
833        debug_assert!(cond_val, $($arg)*);
834        anyhow::ensure!(cond_val, $($arg)*);
835    };
836}
837
838/// Returns early with an error on two expressions inequality.
839/// In non-optimized builds, panics instead if so.
840#[macro_export]
841macro_rules! ensure_and_debug_assert_eq {
842    ($left:expr, $right:expr, $($arg:tt)*) => {
843        match (&$left, &$right) {
844            (left_val, right_val) => {
845                debug_assert_eq!(left_val, right_val, $($arg)*);
846                anyhow::ensure!(left_val == right_val, $($arg)*);
847            }
848        }
849    };
850}
851
852/// Returns early with an error on two expressions equality.
853/// In non-optimized builds, panics instead if so.
854#[macro_export]
855macro_rules! ensure_and_debug_assert_ne {
856    ($left:expr, $right:expr, $($arg:tt)*) => {
857        match (&$left, &$right) {
858            (left_val, right_val) => {
859                debug_assert_ne!(left_val, right_val, $($arg)*);
860                anyhow::ensure!(left_val != right_val, $($arg)*);
861            }
862        }
863    };
864}
865
866/// Logs a warning if a condition is not satisfied.
867/// In non-optimized builds, panics also if so.
868#[macro_export]
869macro_rules! logged_debug_assert {
870    ($ctx:expr, $cond:expr, $($arg:tt)*) => {
871        let cond_val = $cond;
872        if !cond_val {
873            warn!($ctx, $($arg)*);
874        }
875        debug_assert!(cond_val, $($arg)*);
876    };
877}
878
879#[cfg(test)]
880mod tools_tests;
deltachat/tools.rs

deltachat/
tools.rs
