diff --git a/src/config_util.rs b/src/config_util.rs
index c1ec7e0..57850a5 100644
--- a/src/config_util.rs
+++ b/src/config_util.rs
@@ -117,7 +117,7 @@ pub fn parse_config(config_json: &json::JsonValue) -> OSSBackupdConfig {
     let mut items_objects: Vec<OSSBackupdConfigItem> = vec![];
     if items.is_array() {
         for i in 0..items.len() {
-            items_objects.push(parse_oss_backupd_config_item(&items[i], &root_oss_config_object, &encrypt_pubkey_file, &backup_count));
+            items_objects.push(parse_oss_backupd_config_item(&items[i], &root_oss_config_object, &encrypt_pubkey_file, backup_count));
         }
     }
 
@@ -142,16 +142,16 @@ pub fn get_config_json(custom_oss_backupd_config: Option<&str>, verbose: bool) -
 
 fn remove_start_end_slash(s: &str) -> String {
     let mut ss = s;
-    while ss.starts_with("/") {
+    while ss.starts_with('/') {
         ss = &ss[1..]
     }
-    while ss.ends_with("/") {
+    while ss.ends_with('/') {
         ss = &ss[0..(ss.len() - 1)];
     }
     ss.to_owned()
 }
 
-fn parse_oss_backupd_config_item(item: &json::JsonValue, root_oss_config_object: &Option<OSSConfig>, root_encrypt_pubkey_file: &Option<String>, root_backup_count: &Option<u32>) -> OSSBackupdConfigItem {
+fn parse_oss_backupd_config_item(item: &json::JsonValue, root_oss_config_object: &Option<OSSConfig>, root_encrypt_pubkey_file: &Option<String>, root_backup_count: Option<u32>) -> OSSBackupdConfigItem {
     let target = get_string_value(item, "target");
     let file_name = get_string_value(item, "file_name");
     let mut backup_count = get_u32_value(item, "backup_count");
@@ -185,7 +185,7 @@ fn parse_oss_backupd_config_item(item: &json::JsonValue, root_oss_config_object:
         encrypt_pubkey_file = root_encrypt_pubkey_file.clone();
     }
     if backup_count.is_none() && root_backup_count.is_some() {
-        backup_count = root_backup_count.clone();
+        backup_count = root_backup_count;
     }
 
     OSSBackupdConfigItem {
@@ -314,7 +314,7 @@ fn get_config_content(custom_oss_backupd_config: Option<&str>, verbose: bool) ->
 fn get_user_home() -> XResult<String> {
     match dirs::home_dir() {
          None => Err(new_box_ioerror("Home dir not found!")),
-         Some(home_dir) => home_dir.to_str().map(|h| h.to_owned()).ok_or(new_box_ioerror("Home dir not found!")),
+         Some(home_dir) => home_dir.to_str().map(|h| h.to_owned()).ok_or_else(|| new_box_ioerror("Home dir not found!")),
      }
  }
  
diff --git a/src/main.rs b/src/main.rs
index 23adc72..839b1be 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -61,29 +61,29 @@ fn process_config_item(options: &Options, config_item: &OSSBackupdConfigItem,
         print_message(MessageType::DEBUG, &format!("Process config item index: {}, config: {:?}", item_index, config_item));
     }
 
-    let encrypt_pubkey_file = config_item.encrypt_pubkey_file.as_ref().ok_or("encrypt_pubkey_file".to_owned())?;
+    let encrypt_pubkey_file = config_item.encrypt_pubkey_file.as_ref().ok_or_else(|| "encrypt_pubkey_file".to_owned())?;
     if options.verbose {
         print_message(MessageType::DEBUG, &format!("Encrypt pubkey file: {}", encrypt_pubkey_file));
     }
 
-    let target = config_item.target.as_ref().ok_or("target".to_owned())?;
+    let target = config_item.target.as_ref().ok_or_else(|| "target".to_owned())?;
     if options.verbose {
         print_message(MessageType::DEBUG, &format!("Target file: {}", iff!(target.is_empty(), "<empty>", target)));
     }
 
-    let oss_config = config_item.oss_config.as_ref().ok_or("oss_config".to_owned())?;
+    let oss_config = config_item.oss_config.as_ref().ok_or_else(|| "oss_config".to_owned())?;
 
-    let endpoint = oss_config.endpoint.as_ref().ok_or("oss_config#endpoint".to_owned())?;
+    let endpoint = oss_config.endpoint.as_ref().ok_or_else(|| "oss_config#endpoint".to_owned())?;
     if options.verbose {
         print_message(MessageType::DEBUG, &format!("Endpoint: {}", endpoint));
     }
-    let access_key_id = oss_config.access_key_id.as_ref().ok_or("oss_config#access_key_id".to_owned())?;
+    let access_key_id = oss_config.access_key_id.as_ref().ok_or_else(|| "oss_config#access_key_id".to_owned())?;
     if options.verbose {
         print_message(MessageType::DEBUG, &format!("Access key id: {}", access_key_id));
     }
-    let access_key_secret = oss_config.access_key_secret.as_ref().ok_or("oss_config#access_key_secret".to_owned())?;
+    let access_key_secret = oss_config.access_key_secret.as_ref().ok_or_else(|| "oss_config#access_key_secret".to_owned())?;
 
-    let bucket = &oss_config.bucket.as_ref().ok_or("oss_config#bucket".to_owned())?;
+    let bucket = &oss_config.bucket.as_ref().ok_or_else(|| "oss_config#bucket".to_owned())?;
     if options.verbose {
         print_message(MessageType::DEBUG, &format!("Bucket: {}", bucket));
     }
@@ -118,7 +118,7 @@ fn process_config_item(options: &Options, config_item: &OSSBackupdConfigItem,
     let temp_pgp_file = &format!("temp_file_{}.gpg", secs);
 
     let remove_temp_files = || {
-        for f in vec![temp_zip_file, temp_pgp_file] {
+        for f in &[temp_zip_file, temp_pgp_file] {
             if Path::new(f).is_file() {
                 if options.verbose {
                     print_message(MessageType::DEBUG, &format!("Remove file: {}", f));
@@ -211,7 +211,7 @@ fn process_new_backup_file(backup_content_json: &str, new_item: &str, limit: usi
 }
 
 // stringify JSON array
-fn stringity_json_array(vec: &Vec<String>) -> XResult<String> {
+fn stringity_json_array(vec: &[String]) -> XResult<String> {
     let mut json_arr = json::JsonValue::new_array();
     for v in vec {
         json_arr.push(json::JsonValue::from(v.as_str()))?;
diff --git a/src/oss_util.rs b/src/oss_util.rs
index 748b9a9..60434bb 100644
--- a/src/oss_util.rs
+++ b/src/oss_util.rs
@@ -102,7 +102,7 @@ impl OSSClient {
 // https://endpoint, or http://endpoint -> endpoint
 fn remove_endpoint_http_or_s(endpoint: &str) -> String {
     let mut endpoint = endpoint.to_owned();
-    for prefix in vec![HTTP_SS, HTTPS_SS] {
+    for prefix in &[HTTP_SS, HTTPS_SS] {
         if endpoint.starts_with(prefix) {
             endpoint = endpoint.chars().skip(prefix.chars().count()).collect::<String>()
         }
diff --git a/src/pgp_util.rs b/src/pgp_util.rs
index 33fc3f7..e7458e8 100644
--- a/src/pgp_util.rs
+++ b/src/pgp_util.rs
@@ -92,7 +92,7 @@ fn encrypt_read_write(file: &mut File, write: &mut dyn Write) -> XResult<()> {
             Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
             Err(e) => return Err(Box::new(e)),
         };
-        write.write(&buf[..len])?;
+        write.write_all(&buf[..len])?;
         read += len as u64;
         pb.set_position(read);
     }
diff --git a/src/zip_util.rs b/src/zip_util.rs
index df702b7..5b268b7 100644
--- a/src/zip_util.rs
+++ b/src/zip_util.rs
@@ -68,6 +68,6 @@ pub fn zip_file(target: &str, zip_file: &str) -> XResult<()> {
 pub fn get_file_name(path: &Path) -> String {
     match path.file_name() {
         None => "no_file_name".to_owned(),
-        Some(f) => f.to_os_string().into_string().unwrap_or("unknown_file_name".to_owned()),
+        Some(f) => f.to_os_string().into_string().unwrap_or_else(|_| "unknown_file_name".to_owned()),
     }
 }
\ No newline at end of file