deltachat/
download.rs

1//! # Download large messages manually.
2
3use std::collections::BTreeMap;
4
5use anyhow::{Result, anyhow, bail, ensure};
6use deltachat_derive::{FromSql, ToSql};
7use serde::{Deserialize, Serialize};
8
9use crate::context::Context;
10use crate::imap::session::Session;
11use crate::log::warn;
12use crate::message::{self, Message, MsgId, rfc724_mid_exists};
13use crate::{EventType, chatlist_events};
14
15pub(crate) mod post_msg_metadata;
16pub(crate) use post_msg_metadata::PostMsgMetadata;
17
18/// If a message is downloaded only partially
19/// and `delete_server_after` is set to small timeouts (eg. "at once"),
20/// the user might have no chance to actually download that message.
21/// `MIN_DELETE_SERVER_AFTER` increases the timeout in this case.
22pub(crate) const MIN_DELETE_SERVER_AFTER: i64 = 48 * 60 * 60;
23
24/// From this point onward outgoing messages are considered large
25/// and get a Pre-Message, which announces the Post-Message.
26/// This is only about sending so we can modify it any time.
27/// Current value is a bit less than the minimum auto-download setting from the UIs (which is 160
28/// KiB).
29pub(crate) const PRE_MSG_ATTACHMENT_SIZE_THRESHOLD: u64 = 140_000;
30
31/// Max size for pre messages. A warning is emitted when this is exceeded.
32pub(crate) const PRE_MSG_SIZE_WARNING_THRESHOLD: usize = 150_000;
33
34/// Download state of the message.
35#[derive(
36    Debug,
37    Default,
38    Display,
39    Clone,
40    Copy,
41    PartialEq,
42    Eq,
43    FromPrimitive,
44    ToPrimitive,
45    FromSql,
46    ToSql,
47    Serialize,
48    Deserialize,
49)]
50#[repr(u32)]
51pub enum DownloadState {
52    /// Message is fully downloaded.
53    #[default]
54    Done = 0,
55
56    /// Message is partially downloaded and can be fully downloaded at request.
57    Available = 10,
58
59    /// Failed to fully download the message.
60    Failure = 20,
61
62    /// Undecipherable message.
63    Undecipherable = 30,
64
65    /// Full download of the message is in progress.
66    InProgress = 1000,
67}
68
69impl MsgId {
70    /// Schedules Post-Message download for partially downloaded message.
71    pub async fn download_full(self, context: &Context) -> Result<()> {
72        let msg = Message::load_from_db(context, self).await?;
73        match msg.download_state() {
74            DownloadState::Done | DownloadState::Undecipherable => {
75                return Err(anyhow!("Nothing to download."));
76            }
77            DownloadState::InProgress => return Err(anyhow!("Download already in progress.")),
78            DownloadState::Available | DownloadState::Failure => {
79                if msg.rfc724_mid().is_empty() {
80                    return Err(anyhow!("Download not possible, message has no rfc724_mid"));
81                }
82                self.update_download_state(context, DownloadState::InProgress)
83                    .await?;
84                info!(
85                    context,
86                    "Requesting full download of {:?}.",
87                    msg.rfc724_mid()
88                );
89                context
90                    .sql
91                    .execute(
92                        "INSERT INTO download (rfc724_mid, msg_id) VALUES (?,?)",
93                        (msg.rfc724_mid(), msg.id),
94                    )
95                    .await?;
96                context.scheduler.interrupt_inbox().await;
97            }
98        }
99        Ok(())
100    }
101
102    /// Updates the message download state. Returns `Ok` if the message doesn't exist anymore.
103    pub(crate) async fn update_download_state(
104        self,
105        context: &Context,
106        download_state: DownloadState,
107    ) -> Result<()> {
108        if context
109            .sql
110            .execute(
111                "UPDATE msgs SET download_state=? WHERE id=?;",
112                (download_state, self),
113            )
114            .await?
115            == 0
116        {
117            return Ok(());
118        }
119        let Some(msg) = Message::load_from_db_optional(context, self).await? else {
120            return Ok(());
121        };
122        context.emit_event(EventType::MsgsChanged {
123            chat_id: msg.chat_id,
124            msg_id: self,
125        });
126        chatlist_events::emit_chatlist_item_changed(context, msg.chat_id);
127        Ok(())
128    }
129}
130
131impl Message {
132    /// Returns the download state of the message.
133    pub fn download_state(&self) -> DownloadState {
134        self.download_state
135    }
136}
137
138/// Actually download a message partially downloaded before.
139///
140/// Most messages are downloaded automatically on fetch instead.
141pub(crate) async fn download_msg(
142    context: &Context,
143    rfc724_mid: String,
144    session: &mut Session,
145) -> Result<()> {
146    let transport_id = session.transport_id();
147    let row = context
148        .sql
149        .query_row_optional(
150            "SELECT uid, folder FROM imap
151             WHERE rfc724_mid=?
152             AND transport_id=?
153             AND target!=''",
154            (&rfc724_mid, transport_id),
155            |row| {
156                let server_uid: u32 = row.get(0)?;
157                let server_folder: String = row.get(1)?;
158                Ok((server_uid, server_folder))
159            },
160        )
161        .await?;
162
163    let Some((server_uid, server_folder)) = row else {
164        // No IMAP record found, we don't know the UID and folder.
165        return Err(anyhow!(
166            "IMAP location for {rfc724_mid:?} post-message is unknown"
167        ));
168    };
169
170    session
171        .fetch_single_msg(context, &server_folder, server_uid, rfc724_mid)
172        .await?;
173    Ok(())
174}
175
176impl Session {
177    /// Download a single message and pipe it to receive_imf().
178    ///
179    /// receive_imf() is not directly aware that this is a result of a call to download_msg(),
180    /// however, implicitly knows that as the existing message is flagged as being partly.
181    async fn fetch_single_msg(
182        &mut self,
183        context: &Context,
184        folder: &str,
185        uid: u32,
186        rfc724_mid: String,
187    ) -> Result<()> {
188        if uid == 0 {
189            bail!("Attempt to fetch UID 0");
190        }
191
192        let create = false;
193        let folder_exists = self
194            .select_with_uidvalidity(context, folder, create)
195            .await?;
196        ensure!(folder_exists, "No folder {folder}");
197
198        // we are connected, and the folder is selected
199        info!(context, "Downloading message {}/{} fully...", folder, uid);
200
201        let mut uid_message_ids: BTreeMap<u32, String> = BTreeMap::new();
202        uid_message_ids.insert(uid, rfc724_mid);
203        let (sender, receiver) = async_channel::unbounded();
204        self.fetch_many_msgs(context, folder, vec![uid], &uid_message_ids, sender)
205            .await?;
206        if receiver.recv().await.is_err() {
207            bail!("Failed to fetch UID {uid}");
208        }
209        Ok(())
210    }
211}
212
213async fn set_state_to_failure(context: &Context, rfc724_mid: &str) -> Result<()> {
214    if let Some(msg_id) = rfc724_mid_exists(context, rfc724_mid).await? {
215        // Update download state to failure
216        // so it can be retried.
217        //
218        // On success update_download_state() is not needed
219        // as receive_imf() already
220        // set the state and emitted the event.
221        msg_id
222            .update_download_state(context, DownloadState::Failure)
223            .await?;
224    }
225    Ok(())
226}
227
228async fn available_post_msgs_contains_rfc724_mid(
229    context: &Context,
230    rfc724_mid: &str,
231) -> Result<bool> {
232    Ok(context
233        .sql
234        .query_get_value::<String>(
235            "SELECT rfc724_mid FROM available_post_msgs WHERE rfc724_mid=?",
236            (&rfc724_mid,),
237        )
238        .await?
239        .is_some())
240}
241
242async fn delete_from_available_post_msgs(context: &Context, rfc724_mid: &str) -> Result<()> {
243    context
244        .sql
245        .execute(
246            "DELETE FROM available_post_msgs WHERE rfc724_mid=?",
247            (&rfc724_mid,),
248        )
249        .await?;
250    Ok(())
251}
252
253async fn delete_from_downloads(context: &Context, rfc724_mid: &str) -> Result<()> {
254    context
255        .sql
256        .execute("DELETE FROM download WHERE rfc724_mid=?", (&rfc724_mid,))
257        .await?;
258    Ok(())
259}
260
261pub(crate) async fn msg_is_downloaded_for(context: &Context, rfc724_mid: &str) -> Result<bool> {
262    Ok(message::rfc724_mid_exists(context, rfc724_mid)
263        .await?
264        .is_some())
265}
266
267pub(crate) async fn download_msgs(context: &Context, session: &mut Session) -> Result<()> {
268    let rfc724_mids = context
269        .sql
270        .query_map_vec("SELECT rfc724_mid FROM download", (), |row| {
271            let rfc724_mid: String = row.get(0)?;
272            Ok(rfc724_mid)
273        })
274        .await?;
275
276    for rfc724_mid in &rfc724_mids {
277        let res = download_msg(context, rfc724_mid.clone(), session).await;
278        if res.is_ok() {
279            delete_from_downloads(context, rfc724_mid).await?;
280            delete_from_available_post_msgs(context, rfc724_mid).await?;
281        }
282        if let Err(err) = res {
283            warn!(
284                context,
285                "Failed to download message rfc724_mid={rfc724_mid}: {:#}.", err
286            );
287            if !msg_is_downloaded_for(context, rfc724_mid).await? {
288                // This is probably a classical email that vanished before we could download it
289                warn!(
290                    context,
291                    "{rfc724_mid} download failed and there is no downloaded pre-message."
292                );
293                delete_from_downloads(context, rfc724_mid).await?;
294            } else if available_post_msgs_contains_rfc724_mid(context, rfc724_mid).await? {
295                warn!(
296                    context,
297                    "{rfc724_mid} is in available_post_msgs table but we failed to fetch it,
298                    so set the message to DownloadState::Failure - probably it was deleted on the server in the meantime"
299                );
300                set_state_to_failure(context, rfc724_mid).await?;
301                delete_from_downloads(context, rfc724_mid).await?;
302                delete_from_available_post_msgs(context, rfc724_mid).await?;
303            } else {
304                // leave the message in DownloadState::InProgress;
305                // it will be downloaded once it arrives.
306            }
307        }
308    }
309
310    Ok(())
311}
312
313/// Downloads known post-messages without pre-messages
314/// in order to guard against lost pre-messages.
315pub(crate) async fn download_known_post_messages_without_pre_message(
316    context: &Context,
317    session: &mut Session,
318) -> Result<()> {
319    let rfc724_mids = context
320        .sql
321        .query_map_vec("SELECT rfc724_mid FROM available_post_msgs", (), |row| {
322            let rfc724_mid: String = row.get(0)?;
323            Ok(rfc724_mid)
324        })
325        .await?;
326    for rfc724_mid in &rfc724_mids {
327        if !msg_is_downloaded_for(context, rfc724_mid).await? {
328            // Download the Post-Message unconditionally,
329            // because the Pre-Message got lost.
330            // The message may be in the wrong order,
331            // but at least we have it at all.
332            let res = download_msg(context, rfc724_mid.clone(), session).await;
333            if res.is_ok() {
334                delete_from_available_post_msgs(context, rfc724_mid).await?;
335            }
336            if let Err(err) = res {
337                warn!(
338                    context,
339                    "download_known_post_messages_without_pre_message: Failed to download message rfc724_mid={rfc724_mid}: {:#}.",
340                    err
341                );
342            }
343        }
344    }
345    Ok(())
346}
347
348#[cfg(test)]
349mod tests {
350    use num_traits::FromPrimitive;
351
352    use super::*;
353    use crate::chat::send_msg;
354    use crate::test_utils::TestContext;
355
356    #[test]
357    fn test_downloadstate_values() {
358        // values may be written to disk and must not change
359        assert_eq!(DownloadState::Done, DownloadState::default());
360        assert_eq!(DownloadState::Done, DownloadState::from_i32(0).unwrap());
361        assert_eq!(
362            DownloadState::Available,
363            DownloadState::from_i32(10).unwrap()
364        );
365        assert_eq!(DownloadState::Failure, DownloadState::from_i32(20).unwrap());
366        assert_eq!(
367            DownloadState::InProgress,
368            DownloadState::from_i32(1000).unwrap()
369        );
370    }
371
372    #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
373    async fn test_update_download_state() -> Result<()> {
374        let t = TestContext::new_alice().await;
375        let chat = t.create_chat_with_contact("Bob", "bob@example.org").await;
376
377        let mut msg = Message::new_text("Hi Bob".to_owned());
378        let msg_id = send_msg(&t, chat.id, &mut msg).await?;
379        let msg = Message::load_from_db(&t, msg_id).await?;
380        assert_eq!(msg.download_state(), DownloadState::Done);
381
382        for s in &[
383            DownloadState::Available,
384            DownloadState::InProgress,
385            DownloadState::Failure,
386            DownloadState::Done,
387            DownloadState::Done,
388        ] {
389            msg_id.update_download_state(&t, *s).await?;
390            let msg = Message::load_from_db(&t, msg_id).await?;
391            assert_eq!(msg.download_state(), *s);
392        }
393        t.sql
394            .execute("DELETE FROM msgs WHERE id=?", (msg_id,))
395            .await?;
396        // Nothing to do is ok.
397        msg_id
398            .update_download_state(&t, DownloadState::Done)
399            .await?;
400
401        Ok(())
402    }
403}
deltachat/download.rs

deltachat/
download.rs
