review fix: use impl iterator where appropriate

mm2src/mm2_io/src/fs.rs

@@ -203,14 +203,13 @@ async fn filter_files_by_extension(dir_path: &Path, extension: &str) -> IoResult
 }
 
 /// Helper function to extract file names or stems based on the provided extraction function.
-fn extract_file_identifiers<F>(entries: Vec<PathBuf>, extractor: F) -> Vec<String>
+fn extract_file_identifiers<'a, F>(entries: Vec<PathBuf>, extractor: F) -> impl Iterator<Item = String> + 'a
 where
-    F: Fn(&Path) -> Option<&OsStr>,
+    F: Fn(&Path) -> Option<&OsStr> + 'a,
 {
     entries
         .into_iter()
-        .filter_map(|path| extractor(&path).and_then(OsStr::to_str).map(ToOwned::to_owned))
-        .collect()
+        .filter_map(move |path| extractor(&path).and_then(OsStr::to_str).map(ToOwned::to_owned))
 }
 
 /// Lists files by the specified extension from the given directory path.
@@ -219,7 +218,7 @@ pub async fn list_files_by_extension(
     dir_path: &Path,
     extension: &str,
     include_extension: bool,
-) -> IoResult<Vec<String>> {
+) -> IoResult<impl Iterator<Item = String>> {
     let entries = filter_files_by_extension(dir_path, extension).await?;
     let extractor = if include_extension {
         Path::file_name

mm2src/mm2_main/src/lp_wallet.rs

@@ -538,7 +538,7 @@ impl From<WalletsDBError> for GetWalletsError {
 /// Retrieves all created wallets and the currently activated wallet.
 pub async fn get_wallet_names_rpc(ctx: MmArc, _req: Json) -> MmResult<GetWalletNamesResponse, GetWalletsError> {
     // We want to return wallet names in the same order for both native and wasm32 targets.
-    let wallets = read_all_wallet_names(&ctx).await?.into_iter().sorted().collect();
+    let wallets = read_all_wallet_names(&ctx).await?.sorted().collect();
     // Note: `ok_or` is used here on `Constructible<Option<String>>` to handle the case where the wallet name is not set.
     // `wallet_name` can be `None` in the case of no-login mode.
     let activated_wallet = ctx.wallet_name.ok_or(GetWalletsError::Internal(

mm2src/mm2_main/src/lp_wallet/mnemonics_storage.rs

@@ -62,7 +62,7 @@ pub(super) async fn read_encrypted_passphrase_if_available(ctx: &MmArc) -> Walle
     })
 }
 
-pub(super) async fn read_all_wallet_names(ctx: &MmArc) -> WalletsStorageResult<Vec<String>> {
+pub(super) async fn read_all_wallet_names(ctx: &MmArc) -> WalletsStorageResult<impl Iterator<Item = String>> {
     let wallet_names = list_files_by_extension(&ctx.db_root(), "dat", false)
         .await
         .mm_err(|e| WalletsStorageError::FsReadError(format!("Error reading wallets directory: {}", e)))?;

mm2src/mm2_main/src/lp_wallet/mnemonics_wasm_db.rs

@@ -145,15 +145,15 @@ pub(super) async fn read_encrypted_passphrase_if_available(ctx: &MmArc) -> Walle
         .transpose()
 }
 
-pub(super) async fn read_all_wallet_names(ctx: &MmArc) -> WalletsDBResult<Vec<String>> {
+pub(super) async fn read_all_wallet_names(ctx: &MmArc) -> WalletsDBResult<impl Iterator<Item = String>> {
     let wallets_ctx = WalletsContext::from_ctx(ctx).map_to_mm(WalletsDBError::Internal)?;
 
     let db = wallets_ctx.wallets_db().await?;
     let transaction = db.transaction().await?;
     let table = transaction.table::<MnemonicsTable>().await?;
 
     let all_items = table.get_all_items().await?;
-    let wallet_names = all_items.into_iter().map(|(_, item)| item.wallet_name).collect();
+    let wallet_names = all_items.into_iter().map(|(_, item)| item.wallet_name);
 
     Ok(wallet_names)
 }