accounts: retry filesystem operations in migrate_account()

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Changes
 - deltachat-rpc-client: use `dataclass` for `Account`, `Chat`, `Contact` and `Message` #4042
 - python: mark bindings as supporting typing according to PEP 561 #4045
+- retry filesystem operations during account migration #4043
 
 ### Fixes
 - deltachat-rpc-server: do not block stdin while processing the request. #4041

src/accounts.rs

@@ -1,6 +1,7 @@
 //! # Account manager module.
 
 use std::collections::BTreeMap;
+use std::future::Future;
 use std::path::{Path, PathBuf};
 
 use anyhow::{ensure, Context as _, Result};
@@ -150,27 +151,9 @@ impl Accounts {
         if let Some(cfg) = self.config.get_account(id) {
             let account_path = self.dir.join(cfg.dir);
 
-            // Spend up to 1 minute trying to remove the files.
-            // Files may remain locked up to 30 seconds due to r2d2 bug:
-            // https://github.com/sfackler/r2d2/issues/99
-            let mut counter = 0;
-            loop {
-                counter += 1;
-
-                if let Err(err) = fs::remove_dir_all(&account_path)
-                    .await
-                    .context("failed to remove account data")
-                {
-                    if counter > 60 {
-                        return Err(err);
-                    }
-
-                    // Wait 1 second and try again.
-                    tokio::time::sleep(std::time::Duration::from_millis(1000)).await;
-                } else {
-                    break;
-                }
-            }
+            try_many_times(|| fs::remove_dir_all(&account_path))
+                .await
+                .context("failed to remove account data")?;
         }
         self.config.remove_account(id).await?;
 
@@ -202,10 +185,10 @@ impl Accounts {
             fs::create_dir_all(self.dir.join(&account_config.dir))
                 .await
                 .context("failed to create dir")?;
-            fs::rename(&dbfile, &new_dbfile)
+            try_many_times(|| fs::rename(&dbfile, &new_dbfile))
                 .await
                 .context("failed to rename dbfile")?;
-            fs::rename(&blobdir, &new_blobdir)
+            try_many_times(|| fs::rename(&blobdir, &new_blobdir))
                 .await
                 .context("failed to rename blobdir")?;
             if walfile.exists() {
@@ -229,11 +212,10 @@ impl Accounts {
                 Ok(account_config.id)
             }
             Err(err) => {
-                // remove temp account
-                fs::remove_dir_all(std::path::PathBuf::from(&account_config.dir))
+                let account_path = std::path::PathBuf::from(&account_config.dir);
+                try_many_times(|| fs::remove_dir_all(&account_path))
                     .await
                     .context("failed to remove account data")?;
-
                 self.config.remove_account(account_config.id).await?;
 
                 // set selection back
@@ -488,6 +470,33 @@ impl Config {
     }
 }
 
+/// Spend up to 1 minute trying to do the operation.
+///
+/// Files may remain locked up to 30 seconds due to r2d2 bug:
+/// <https://github.com/sfackler/r2d2/issues/99>
+async fn try_many_times<F, Fut, T>(f: F) -> std::result::Result<(), T>
+where
+    F: Fn() -> Fut,
+    Fut: Future<Output = std::result::Result<(), T>>,
+{
+    let mut counter = 0;
+    loop {
+        counter += 1;
+
+        if let Err(err) = f().await {
+            if counter > 60 {
+                return Err(err);
+            }
+
+            // Wait 1 second and try again.
+            tokio::time::sleep(std::time::Duration::from_millis(1000)).await;
+        } else {
+            break;
+        }
+    }
+    Ok(())
+}
+
 /// Configuration of a single account.
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq)]
 struct AccountConfig {