[pbs-devel] [PATCH backup v3 2/2] api: use if-let pattern for error-only handling

Fabian Grünbichler f.gruenbichler at proxmox.com
Tue Feb 13 15:04:49 CET 2024


On February 13, 2024 1:43 pm, Maximiliano Sandoval wrote:
> It is more readable than using match. We also inline variables in
> eprintln!.

this does a lot more than what it says here..

> 
> Signed-off-by: Maximiliano Sandoval <m.sandoval at proxmox.com>
> ---
>  pbs-client/src/pxar/dir_stack.rs            |  9 ++--
>  pbs-pxar-fuse/src/lib.rs                    | 47 ++++++++++++---------
>  src/api2/access/user.rs                     | 20 ++-------
>  src/bin/proxmox-daily-update.rs             |  7 +--
>  src/tape/pool_writer/new_chunks_iterator.rs |  9 ++--
>  src/tools/parallel_handler.rs               | 11 ++---
>  src/traffic_control_cache.rs                |  7 +--
>  7 files changed, 45 insertions(+), 65 deletions(-)
> 
> diff --git a/pbs-client/src/pxar/dir_stack.rs b/pbs-client/src/pxar/dir_stack.rs
> index 43cbee1d..616d7545 100644
> --- a/pbs-client/src/pxar/dir_stack.rs
> +++ b/pbs-client/src/pxar/dir_stack.rs
> @@ -40,16 +40,13 @@ impl PxarDir {
>          parent: RawFd,
>          allow_existing_dirs: bool,
>      ) -> Result<BorrowedFd, Error> {
> -        match mkdirat(
> +        if let Err(err) = mkdirat(
>              parent,
>              self.file_name.as_os_str(),
>              perms_from_metadata(&self.metadata)?,
>          ) {
> -            Ok(()) => (),
> -            Err(err) => {
> -                if !(allow_existing_dirs && err.already_exists()) {
> -                    return Err(err.into());
> -                }
> +            if !(allow_existing_dirs && err.already_exists()) {
> +                return Err(err.into());

fine

>              }
>          }
>  
> diff --git a/pbs-pxar-fuse/src/lib.rs b/pbs-pxar-fuse/src/lib.rs
> index 98d28c57..5c2b6b49 100644
> --- a/pbs-pxar-fuse/src/lib.rs
> +++ b/pbs-pxar-fuse/src/lib.rs
> @@ -525,9 +525,11 @@ impl SessionImpl {
>              let file = file?.decode_entry().await?;
>              let stat = to_stat(to_inode(&file), &file)?;
>              let name = file.file_name();
> -            match request.add_entry(name, &stat, next, 1, f64::MAX, f64::MAX)? {
> -                ReplyBufState::Ok => (),
> -                ReplyBufState::Full => return Ok(lookups),
> +            if request
> +                .add_entry(name, &stat, next, 1, f64::MAX, f64::MAX)?
> +                .is_full()
> +            {
> +                return Ok(lookups);

not error handling, but semantically equivalent to if-let, okay..

>              }
>              lookups.push(self.make_lookup(request.inode, stat.st_ino, &file)?);
>          }
> @@ -537,9 +539,11 @@ impl SessionImpl {
>              let file = dir.lookup_self().await?;
>              let stat = to_stat(to_inode(&file), &file)?;
>              let name = OsStr::new(".");
> -            match request.add_entry(name, &stat, next, 1, f64::MAX, f64::MAX)? {
> -                ReplyBufState::Ok => (),
> -                ReplyBufState::Full => return Ok(lookups),
> +            if request
> +                .add_entry(name, &stat, next, 1, f64::MAX, f64::MAX)?
> +                .is_full()
> +            {
> +                return Ok(lookups);

same

>              }
>              lookups.push(LookupRef::clone(&dir_lookup));
>          }
> @@ -551,9 +555,11 @@ impl SessionImpl {
>              let file = parent_dir.lookup_self().await?;
>              let stat = to_stat(to_inode(&file), &file)?;
>              let name = OsStr::new("..");
> -            match request.add_entry(name, &stat, next, 1, f64::MAX, f64::MAX)? {
> -                ReplyBufState::Ok => (),
> -                ReplyBufState::Full => return Ok(lookups),
> +            if request
> +                .add_entry(name, &stat, next, 1, f64::MAX, f64::MAX)?
> +                .is_full()
> +            {
> +                return Ok(lookups);

same

>              }
>              lookups.push(lookup);
>          }
> @@ -618,24 +624,25 @@ impl SessionImpl {
>      ) -> Result<ReplyBufState, Error> {
>          let xattrs = self.listxattrs(request.inode).await?;
>  
> -        for entry in xattrs {
> -            match request.add_c_string(entry.name()) {
> -                ReplyBufState::Ok => (),
> -                ReplyBufState::Full => return Ok(ReplyBufState::Full),
> -            }
> +        if xattrs
> +            .iter()
> +            .any(|entry| request.add_c_string(entry.name()).is_full())
> +        {
> +            Ok(ReplyBufState::Full)
> +        } else {
> +            Ok(ReplyBufState::Ok)

this is not an if-let at all (and also not error handling ;)), even
though the end result is of course the same..

>          }
> -
> -        Ok(ReplyBufState::Ok)
>      }
>  
>      async fn getxattr(&self, inode: u64, xattr: &OsStr) -> Result<pxar::format::XAttr, Error> {
>          // TODO: pxar::Accessor could probably get a more optimized method to fetch a specific
>          // xattr for an entry...
>          let xattrs = self.listxattrs(inode).await?;
> -        for entry in xattrs {
> -            if entry.name().to_bytes() == xattr.as_bytes() {
> -                return Ok(entry);
> -            }
> +        if xattrs
> +            .iter()
> +            .any(|entry| request.add_c_string(entry.name()).is_full())
> +        {
> +            return Ok(entry);

but this here is an obvious copy paste error that doesn't even compile!
please check patches before sending, even if they are supposedly trivial
style fixes!

>          }
>          io_return!(libc::ENODATA);
>      }
> diff --git a/src/api2/access/user.rs b/src/api2/access/user.rs
> index 118838ce..a0be6111 100644
> --- a/src/api2/access/user.rs
> +++ b/src/api2/access/user.rs
> @@ -381,28 +381,16 @@ pub fn delete_user(userid: Userid, digest: Option<String>) -> Result<(), Error>
>      pbs_config::user::save_config(&config)?;
>  
>      let authenticator = crate::auth::lookup_authenticator(userid.realm())?;
> -    match authenticator.remove_password(userid.name()) {
> -        Ok(()) => {}
> -        Err(err) => {
> -            eprintln!(
> -                "error removing password after deleting user {:?}: {}",
> -                userid, err
> -            );
> -        }
> +    if let Err(err) = authenticator.remove_password(userid.name()) {
> +        eprintln!("error removing password after deleting user {userid:?}: {err}",);

this one seems fine

>      }
>  
> -    match crate::config::tfa::read().and_then(|mut cfg| {
> +    if let Err(err) = crate::config::tfa::read().and_then(|mut cfg| {
>          let _: proxmox_tfa::api::NeedsSaving =
>              cfg.remove_user(&crate::config::tfa::UserAccess, userid.as_str())?;
>          crate::config::tfa::write(&cfg)
>      }) {
> -        Ok(()) => (),
> -        Err(err) => {
> -            eprintln!(
> -                "error updating TFA config after deleting user {:?}: {}",
> -                userid, err
> -            );
> -        }
> +        eprintln!("error updating TFA config after deleting user {userid:?} {err}",);

this one as well

>      }
>  
>      Ok(())
> diff --git a/src/bin/proxmox-daily-update.rs b/src/bin/proxmox-daily-update.rs
> index ae3744c5..c22609c5 100644
> --- a/src/bin/proxmox-daily-update.rs
> +++ b/src/bin/proxmox-daily-update.rs
> @@ -55,11 +55,8 @@ async fn do_update(rpcenv: &mut dyn RpcEnvironment) -> Result<(), Error> {
>          _ => unreachable!(),
>      };
>  
> -    match check_acme_certificates(rpcenv).await {
> -        Ok(()) => (),
> -        Err(err) => {
> -            log::error!("error checking certificates: {}", err);
> -        }
> +    if let Err(err) = check_acme_certificates(rpcenv).await {
> +        log::error!("error checking certificates: {err}");

okay as well

>      }
>  
>      // TODO: cleanup tasks like in PVE?
> diff --git a/src/tape/pool_writer/new_chunks_iterator.rs b/src/tape/pool_writer/new_chunks_iterator.rs
> index ae75b7b1..1454b33d 100644
> --- a/src/tape/pool_writer/new_chunks_iterator.rs
> +++ b/src/tape/pool_writer/new_chunks_iterator.rs
> @@ -57,12 +57,9 @@ impl NewChunksIterator {
>  
>                      let blob = datastore.load_chunk(&digest)?;
>                      //println!("LOAD CHUNK {}", hex::encode(&digest));
> -                    match tx.send(Ok(Some((digest, blob)))) {
> -                        Ok(()) => {}
> -                        Err(err) => {
> -                            eprintln!("could not send chunk to reader thread: {}", err);
> -                            break;
> -                        }
> +                    if let Err(err) = tx.send(Ok(Some((digest, blob)))) {
> +                        eprintln!("could not send chunk to reader thread: {err}");
> +                        break;

okay

>                      }
>  
>                      chunk_index.insert(digest);
> diff --git a/src/tools/parallel_handler.rs b/src/tools/parallel_handler.rs
> index c4316ad0..17f70179 100644
> --- a/src/tools/parallel_handler.rs
> +++ b/src/tools/parallel_handler.rs
> @@ -80,13 +80,10 @@ impl<I: Send + 'static> ParallelHandler<I> {
>                              Ok(data) => data,
>                              Err(_) => return,
>                          };
> -                        match (handler_fn)(data) {
> -                            Ok(()) => (),
> -                            Err(err) => {
> -                                let mut guard = abort.lock().unwrap();
> -                                if guard.is_none() {
> -                                    *guard = Some(err.to_string());
> -                                }
> +                        if let Err(err) = (handler_fn)(data) {
> +                            let mut guard = abort.lock().unwrap();
> +                            if guard.is_none() {
> +                                *guard = Some(err.to_string());

okay

>                              }
>                          }
>                      })
> diff --git a/src/traffic_control_cache.rs b/src/traffic_control_cache.rs
> index 2e097d70..4c3bccee 100644
> --- a/src/traffic_control_cache.rs
> +++ b/src/traffic_control_cache.rs
> @@ -164,11 +164,8 @@ impl TrafficControlCache {
>          self.last_traffic_control_generation = traffic_control_generation;
>          self.last_update = now;
>  
> -        match self.reload_impl() {
> -            Ok(()) => (),
> -            Err(err) => {
> -                log::error!("TrafficControlCache::reload failed -> {}", err);
> -            }
> +        if let Err(err) = self.reload_impl() {
> +            log::error!("TrafficControlCache::reload failed -> {err}");

okay

>          }
>      }
>  
> -- 
> 2.39.2
> 
> 
> 
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