first commit

src/db.rs

@@ -871,6 +871,38 @@ impl Db {
         Ok(out)
     }
 
+    /// Subscribers per feed, for the whole catalogue in one query -- the feed list would
+    /// otherwise ask once per feed.
+    pub fn subscriber_counts(&self) -> Result<std::collections::HashMap<String, i64>> {
+        let conn = self.conn.lock().unwrap();
+        let mut stmt =
+            conn.prepare("SELECT feed_id, count(*) FROM subscriptions GROUP BY feed_id")?;
+        let out = stmt
+            .query_map([], |r| Ok((r.get::<_, String>(0)?, r.get::<_, i64>(1)?)))?
+            .collect::<rusqlite::Result<std::collections::HashMap<_, _>>>()?;
+        Ok(out)
+    }
+
+    /// Who else would miss this file: subscribers other than `user_id` who have starred
+    /// the item or have not read it yet. Deleting is deleting their copy too.
+    pub fn others_wanting(&self, enclosure_id: i64, user_id: i64) -> Result<(i64, i64)> {
+        let conn = self.conn.lock().unwrap();
+        let mut stmt = conn.prepare(
+            "SELECT
+                sum(CASE WHEN coalesce(st.flagged, 0) = 1 THEN 1 ELSE 0 END),
+                sum(CASE WHEN coalesce(st.read, 0) = 0 THEN 1 ELSE 0 END)
+             FROM enclosures e
+             JOIN subscriptions s ON s.feed_id = e.feed_id AND s.user_id != ?2
+             LEFT JOIN entry_state st
+                    ON st.user_id = s.user_id AND st.feed_id = e.feed_id AND st.guid = e.guid
+             WHERE e.id = ?1",
+        )?;
+        let (starred, unread) = stmt.query_row(params![enclosure_id, user_id], |r| {
+            Ok((r.get::<_, Option<i64>>(0)?.unwrap_or(0), r.get::<_, Option<i64>>(1)?.unwrap_or(0)))
+        })?;
+        Ok((starred, unread))
+    }
+
     pub fn subscribe(&self, user_id: i64, feed_id: &str) -> Result<()> {
         let conn = self.conn.lock().unwrap();
         conn.execute(
@@ -1274,6 +1306,32 @@ pub fn now() -> i64 {
 mod tests {
     use super::*;
 
+    #[test]
+    fn deleting_a_shared_file_asks_about_everyone_else() {
+        let db = Db::memory().unwrap();
+        db.exec_for_test(
+            "INSERT INTO users (id, name, is_admin, created) VALUES (1,'ray',1,0),(2,'sam',0,0),(3,'kit',0,0);
+             INSERT INTO subscriptions (user_id, feed_id, created) VALUES (1,'f',0),(2,'f',0),(3,'f',0);
+             INSERT INTO entries (feed_id, guid, first_seen) VALUES ('f','a',0);
+             INSERT INTO enclosures (id, feed_id, guid, url, path, state) VALUES
+                (1,'f','a','u1','/tmp/a','done');",
+        )
+        .unwrap();
+
+        // Nobody has touched it: both others still have it unplayed.
+        assert_eq!(db.others_wanting(1, 1).unwrap(), (0, 2));
+
+        // Sam reads it, Kit stars it.
+        db.set_entry_flag(2, "f", "a", EntryFlag::Read, true).unwrap();
+        db.set_entry_flag(3, "f", "a", EntryFlag::Flagged, true).unwrap();
+        assert_eq!(db.others_wanting(1, 1).unwrap(), (1, 1), "one starred it, one has not played it");
+
+        // Asking as Kit, only Ray and Sam count -- and Kit's own star is not a reason to
+        // warn Kit.
+        db.set_entry_flag(1, "f", "a", EntryFlag::Read, true).unwrap();
+        assert_eq!(db.others_wanting(1, 3).unwrap(), (0, 0));
+    }
+
     #[test]
     fn read_state_belongs_to_one_person() {
         let db = Db::memory().unwrap();

src/web.rs

@@ -346,6 +346,8 @@ struct FeedRow {
     entries: i64,
     downloaded: i64,
     unread: i64,
+    /// Including you. More than one means every file here is shared.
+    subscribers: i64,
 }
 
 async fn feeds(
@@ -363,6 +365,7 @@ async fn feeds(
         .into_iter()
         .map(|s| (s.feed_id.clone(), s))
         .collect();
+    let counts = state.ctx.db.subscriber_counts()?;
     let mut out = Vec::with_capacity(mine.len());
     for sub in &subs {
         let (id, feed) = (&sub.id, &sub.cfg);
@@ -400,6 +403,7 @@ async fn feeds(
             entries: s.entries,
             downloaded: s.downloaded,
             unread: state.ctx.db.unread_count(user.id, id)?,
+            subscribers: counts.get(id).copied().unwrap_or(0),
         });
     }
     Ok(Json(out))
@@ -822,15 +826,46 @@ async fn download_now(
     Ok(StatusCode::ACCEPTED)
 }
 
+#[derive(Deserialize)]
+struct Force {
+    #[serde(default)]
+    force: bool,
+}
+
 async fn delete_file(
     State(state): State<WebState>,
     Path(id): Path<i64>,
+    user: crate::db::User,
+    Query(q): Query<Force>,
 ) -> Result<StatusCode, ApiError> {
     let enc = state
         .ctx
         .db
         .enclosure(id)?
         .ok_or_else(|| anyhow::anyhow!("no enclosure {id}"))?;
+
+    // There is one copy of the file: deleting it deletes everyone's. Say so before doing
+    // it, once, and let them decide.
+    if !q.force {
+        let (starred, unread) = state.ctx.db.others_wanting(id, user.id)?;
+        let people = |n: i64| if n == 1 { "person".to_string() } else { format!("{n} people") };
+        let complaint = match (starred, unread) {
+            (0, 0) => None,
+            (0, u) => Some(format!("{} subscribed to this feed {} not played it yet", people(u), if u == 1 { "has" } else { "have" })),
+            (st, 0) => Some(format!("another {} starred it to keep", people(st))),
+            (st, u) => Some(format!(
+                "another {} starred it to keep, and {} not played it yet",
+                people(st),
+                if u == 1 { "one person has".to_string() } else { format!("{u} have") }
+            )),
+        };
+        if let Some(why) = complaint {
+            return Err(ApiError {
+                error: anyhow::Error::msg(format!("There is one copy of this file and {why}.")),
+                status: StatusCode::CONFLICT,
+            });
+        }
+    }
     if let Some(path) = &enc.path
         && let Err(e) = std::fs::remove_file(path)
         && e.kind() != std::io::ErrorKind::NotFound

tests/ui/app.spec.js

@@ -298,5 +298,28 @@ test('a second person has their own feeds and their own read state', async ({ br
   await page.locator('.tabs button', { hasText: 'Unread' }).click();
   await expect(page.locator('.ep')).toHaveCount(rows);
 
+  // Two people now share this feed, so the page says so and Delete is honest about it.
+  await expect(page.locator('#content .sub').first()).toContainText('shared with 1 other person');
+
   await ctx.close();
 });
+
+test('deleting a shared file warns that it is everyone\'s copy', async ({ page }) => {
+  // Admin and Sam both subscribe to Test Show by now; the daemon downloaded one file.
+  await page.getByText('Test Show').click();
+  await page.locator('.tabs button', { hasText: 'Downloaded' }).click();
+  const row = page.locator('.ep').first();
+  await expect(row).toBeVisible({ timeout: 20_000 });
+  await row.click();
+
+  const del = page.locator('#detail button', { hasText: 'Delete' });
+  await expect(del).toHaveText(/Delete for everyone/);
+
+  // First prompt: the browser confirm. Say yes, then decline the server's warning, and
+  // the file must still be there.
+  page.once('dialog', d => d.accept());
+  const second = new Promise(resolve => page.once('dialog', d => { resolve(d.message()); d.dismiss(); }));
+  await del.click();
+  expect(await second).toContain('one copy of this file');
+  await expect(page.locator('#detail button', { hasText: 'Delete' })).toBeVisible();
+});

web/index.html

@@ -574,7 +574,8 @@ function renderFeed(){
       <div class="meta">
         <h2>${esc(f.title||f.id)}</h2>
         <div class="sub">${f.entries} items · ${f.downloaded} downloaded · checked ${ago(f.last_checked)}
-          · every ${everyText(f.every_mins)}${f.next_check?` · next ${due(f.next_check)}`:''}</div>
+          · every ${everyText(f.every_mins)}${f.next_check?` · next ${due(f.next_check)}`:''}${
+          f.subscribers>1?` · shared with ${f.subscribers-1} other ${f.subscribers===2?'person':'people'}`:''}</div>
         ${f.last_error?`<div class="sub" style="color:var(--bad)">${esc(f.last_error)}</div>`:''}
         ${f.orphaned?`<div class="sub" style="color:var(--warn)">This feed is no longer listed in its
           OPML subscription. It was kept rather than removed because it has downloaded items.</div>`:''}
@@ -861,6 +862,12 @@ function showDetail(e){
 /// One enclosure: a player when the file is here, otherwise what it is and a way to get it.
 function encBox(x){
   const size=x.length?mb(x.length):'';
+  // One file serves everyone reading the feed, so deleting is not a private act.
+  const f=S.feeds.find(y=>y.id===S.feed);
+  const shared=f&&f.subscribers>1;
+  const delBtn=`<button class="btn danger" data-a="del" data-enc="${x.id}"${
+    shared?` title="Shared with ${f.subscribers-1} other ${f.subscribers===2?'person':'people'} reading this feed"`:''
+  }>Delete${shared?' for everyone':' file'}</button>`;
   if(x.path && !isPlayable(x)){
     // On disk, but not audio or video: view it, keep it, or remove it -- no player.
     return `<div class="encbox">
@@ -868,7 +875,7 @@ function encBox(x){
       <span class="meta" style="flex:1">downloaded${size?' \u00b7 '+size:''}</span>
       <a class="btn" href="/media/${x.id}" target="_blank" rel="noopener noreferrer">View</a>
       <a class="btn" href="/media/${x.id}" download>Save</a>
-      <button class="btn danger" data-a="del" data-enc="${x.id}">Delete file</button>
+      ${delBtn}
     </div>`;
   }
   if(x.path){
@@ -876,7 +883,7 @@ function encBox(x){
       <audio id="audio-${x.id}" controls preload="none" src="/media/${x.id}"></audio>
       <span class="meta">${size}</span>
       <a class="btn" href="/media/${x.id}" download>Save</a>
-      <button class="btn danger" data-a="del" data-enc="${x.id}">Delete file</button>
+      ${delBtn}
     </div>`;
   }
   // Nothing on disk. For an image or a PDF you usually just want to look at it, so link
@@ -908,8 +915,21 @@ async function epAction(a,e,el,encId){
       toast('Queued: '+(e.title||'item'));
     }
     if(a==='del'){
-      if(!confirm('Delete the downloaded file?\n\nThe item stays listed and will not be downloaded again automatically.')) return;
+      const f=S.feeds.find(x=>x.id===e.feed_id);
+      const shared=f&&f.subscribers>1;
+      if(!confirm(shared
+        ? `Delete this file?\n\nThere is one copy, shared with ${f.subscribers-1} other `
+          +`${f.subscribers===2?'person':'people'} reading this feed. The item stays listed `
+          +`and will not be downloaded again automatically.`
+        : 'Delete the downloaded file?\n\nThe item stays listed and will not be downloaded again automatically.')) return;
+      try{
         await api(`/api/enclosures/${enc.id}`,{method:'DELETE'});
+      }catch(err){
+        // 409: somebody else has it starred or unplayed. Their reason, their words.
+        if(!/one copy of this file/.test(err.message)) throw err;
+        if(!confirm(err.message+'\n\nDelete it anyway?')) return;
+        await api(`/api/enclosures/${enc.id}?force=true`,{method:'DELETE'});
+      }
       toast('Deleted'); loadEntries(); loadFeeds(true);
     }
   }catch(err){ toast(err.message,true); }