Fix long filenames containing dots (#3098)

CHANGELOG.md

@@ -18,6 +18,8 @@
 - keep track of securejoin joiner status in database to survive restarts #2920
 - remove never used `SentboxMove` option #3111
 
+### Fixes
+- Fix a bug where sometimes the file extension of a long filename containing a dot was cropped #3098
 
 ## 1.76.0
 

src/blob.rs

@@ -345,13 +345,30 @@ impl<'a> BlobObject<'a> {
         };
 
         let clean = sanitize_filename::sanitize_with_options(name, opts);
+        // Let's take the tricky filename
+        // "file.with_lots_of_characters_behind_point_and_double_ending.tar.gz" as an example.
+        // Split it into "file" and "with_lots_of_characters_behind_point_and_double_ending.tar.gz":
         let mut iter = clean.splitn(2, '.');
+
         let stem: String = iter.next().unwrap_or_default().chars().take(64).collect();
-        let ext: String = iter.next().unwrap_or_default().chars().take(32).collect();
+        // stem == "file"
+
+        let ext_chars = iter.next().unwrap_or_default().chars();
+        let ext: String = ext_chars
+            .rev()
+            .take(32)
+            .collect::<Vec<_>>()
+            .iter()
+            .rev()
+            .collect();
+        // ext == "d_point_and_double_ending.tar.gz"
+
         if ext.is_empty() {
             (stem, "".to_string())
         } else {
             (stem, format!(".{}", ext).to_lowercase())
+            // Return ("file", ".d_point_and_double_ending.tar.gz")
+            // which is not perfect but acceptable.
         }
     }
 

src/dc_receive_imf.rs

@@ -2333,6 +2333,9 @@ async fn add_or_lookup_contact_by_addr(
 #[cfg(test)]
 mod tests {
 
+    use async_std::fs::{self, File};
+    use async_std::io::WriteExt;
+
     use super::*;
 
     use crate::chat::get_chat_contacts;
@@ -2340,7 +2343,7 @@ mod tests {
     use crate::chatlist::Chatlist;
     use crate::constants::{DC_CONTACT_ID_INFO, DC_GCL_NO_SPECIALS};
     use crate::message::Message;
-    use crate::test_utils::{get_chat_msg, TestContext};
+    use crate::test_utils::{get_chat_msg, TestContext, TestContextManager};
 
     #[test]
     fn test_hex_hash() {
@@ -4968,4 +4971,59 @@ Reply from different address
 
         Ok(())
     }
+
+    #[async_std::test]
+    async fn test_long_filenames() -> Result<()> {
+        let mut tcm = TestContextManager::new().await;
+        let alice = tcm.alice().await;
+        let bob = tcm.bob().await;
+
+        for filename_sent in &[
+            "foo.bar very long file name test baz.tar.gz",
+            "foobarabababababababbababababverylongfilenametestbaz.tar.gz",
+            "fooo...tar.gz",
+            "foo. .tar.gz",
+            "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.tar.gz",
+            "a.tar.gz",
+            "a.a..a.a.a.a.tar.gz",
+        ] {
+            let attachment = alice.blobdir.join(filename_sent);
+            let content = format!("File content of {}", filename_sent);
+            File::create(&attachment)
+                .await?
+                .write_all(content.as_bytes())
+                .await?;
+
+            let mut msg_alice = Message::new(Viewtype::File);
+            msg_alice.set_file(attachment.to_str().unwrap(), None);
+            let alice_chat = alice.create_chat(&bob).await;
+            let sent = alice.send_msg(alice_chat.id, &mut msg_alice).await;
+            println!("{}", sent.payload());
+
+            bob.recv_msg(&sent).await;
+            let msg_bob = bob.get_last_msg().await;
+
+            async fn check_message(msg: &Message, t: &TestContext, content: &str) {
+                assert_eq!(msg.get_viewtype(), Viewtype::File);
+                let resulting_filename = msg.get_filename().unwrap();
+                let path = msg.get_file(t).unwrap();
+                assert!(
+                    resulting_filename.ends_with(".tar.gz"),
+                    "{:?} doesn't end with .tar.gz, path: {:?}",
+                    resulting_filename,
+                    path
+                );
+                assert!(
+                    path.to_str().unwrap().ends_with(".tar.gz"),
+                    "path {:?} doesn't end with .tar.gz",
+                    path
+                );
+                assert_eq!(fs::read_to_string(path).await.unwrap(), content);
+            }
+            check_message(&msg_alice, &alice, &content).await;
+            check_message(&msg_bob, &bob, &content).await;
+        }
+
+        Ok(())
+    }
 }