Iteration optimisation

Cargo.toml

@@ -124,3 +124,7 @@ test-attestation-cert-ids = []
 [package.metadata.docs.rs]
 features = ["serde-extensions", "virt"]
 rustdoc-args = ["--cfg", "docsrs"]
+
+[patch.crates-io]
+littlefs2-sys = { git = "https://github.com/sosthene-nitrokey/littlefs2-sys.git", branch = "update" }
+littlefs2 = { git = "https://github.com/sosthene-nitrokey/littlefs2.git", branch = "iter-optimization" }

src/api.rs

@@ -41,6 +41,7 @@ generate_enums! {
     Hash: 12
     // TODO: add ReadDir{First,Next}, not loading data, if needed for efficiency
     ReadDirFilesFirst: 13
+    ReadDirFilesNth: 63
     ReadDirFilesNext: 14
     ReadFile: 15
     Metadata: 26
@@ -63,6 +64,7 @@ generate_enums! {
 
     // // CreateDir,    <-- implied by WriteFile
     ReadDirFirst: 31 //      <-- gets Option<FileType> to restrict to just dir/file DirEntries,
+    ReadDirNth: 64
     ReadDirNext: 32 //      <-- gets Option<FileType> to restrict to just dir/file DirEntries,
     //                   // returns simplified Metadata
     // // ReadDirFilesFirst: 23 // <-- returns contents
@@ -229,13 +231,24 @@ pub mod request {
           - dir: PathBuf
           - user_attribute: Option<UserAttribute>
 
+        ReadDirFilesNth:
+          - location: Location
+          - dir: PathBuf
+          - start_at: usize
+          - user_attribute: Option<UserAttribute>
+
         ReadDirFilesNext:
 
         ReadDirFirst:
           - location: Location
           - dir: PathBuf
           - not_before_filename: Option<PathBuf>
 
+        ReadDirNth:
+          - location: Location
+          - dir: PathBuf
+          - start_at: usize
+
         ReadDirNext:
 
         ReadFile:
@@ -419,12 +432,18 @@ pub mod reply {
         ReadDirFilesFirst:
           - data: Option<Message>
 
+        ReadDirFilesNth:
+          - data: Option<Message>
+
         ReadDirFilesNext:
           - data: Option<Message>
 
         ReadDirFirst:
           - entry: Option<DirEntry>
 
+        ReadDirNth:
+          - entry: Option<DirEntry>
+
         ReadDirNext:
           - entry: Option<DirEntry>
 

src/api/macros.rs

@@ -2,17 +2,19 @@ macro_rules! generate_enums {
     ($($(#[$attr:meta])? $which:ident: $index:literal)*) => {
 
     #[derive(Clone, Eq, PartialEq, Debug)]
+    #[repr(u8)]
     #[allow(clippy::large_enum_variant)]
     #[non_exhaustive]
     pub enum Request {
-        DummyRequest, // for testing
+        DummyRequest = 0, // for testing
         $(
         $(#[$attr])?
-        $which(request::$which),
+        $which(request::$which) = $index,
         )*
     }
 
     #[derive(Clone, Eq, PartialEq, Debug)]
+    #[repr(u8)]
     #[allow(clippy::large_enum_variant)]
     #[non_exhaustive]
     pub enum Reply {

src/client.rs

@@ -569,6 +569,19 @@ pub trait FilesystemClient: PollClient {
         })
     }
 
+    fn read_dir_nth(
+        &mut self,
+        location: Location,
+        dir: PathBuf,
+        start_at: usize,
+    ) -> ClientResult<'_, reply::ReadDirNth, Self> {
+        self.request(request::ReadDirNth {
+            location,
+            dir,
+            start_at,
+        })
+    }
+
     fn read_dir_next(&mut self) -> ClientResult<'_, reply::ReadDirNext, Self> {
         self.request(request::ReadDirNext {})
     }
@@ -586,6 +599,21 @@ pub trait FilesystemClient: PollClient {
         })
     }
 
+    fn read_dir_files_nth(
+        &mut self,
+        location: Location,
+        dir: PathBuf,
+        start_at: usize,
+        user_attribute: Option<UserAttribute>,
+    ) -> ClientResult<'_, reply::ReadDirFilesNth, Self> {
+        self.request(request::ReadDirFilesNth {
+            dir,
+            location,
+            start_at,
+            user_attribute,
+        })
+    }
+
     fn read_dir_files_next(&mut self) -> ClientResult<'_, reply::ReadDirFilesNext, Self> {
         self.request(request::ReadDirFilesNext {})
     }

src/service.rs

@@ -355,6 +355,20 @@ impl<P: Platform> ServiceResources<P> {
                 };
                 Ok(Reply::ReadDirFirst(reply::ReadDirFirst { entry: maybe_entry } ))
             }
+            Request::ReadDirNth(request) => {
+                let maybe_entry = match filestore.read_dir_nth(&request.dir, request.location, request.start_at)? {
+                    Some((entry, read_dir_state)) => {
+                        ctx.read_dir_state = Some(read_dir_state);
+                        Some(entry)
+                    }
+                    None => {
+                        ctx.read_dir_state = None;
+                        None
+
+                    }
+                };
+                Ok(Reply::ReadDirNth(reply::ReadDirNth { entry: maybe_entry } ))
+            }
 
             Request::ReadDirNext(_request) => {
                 // ensure next call has nothing to work with, unless we store state again
@@ -393,6 +407,20 @@ impl<P: Platform> ServiceResources<P> {
                 Ok(Reply::ReadDirFilesFirst(reply::ReadDirFilesFirst { data: maybe_data } ))
             }
 
+            Request::ReadDirFilesNth(request) => {
+                let maybe_data = match filestore.read_dir_files_nth(&request.dir, request.location, request.start_at, request.user_attribute.clone())? {
+                    Some((data, state)) => {
+                        ctx.read_dir_files_state = Some(state);
+                        data
+                    }
+                    None => {
+                        ctx.read_dir_files_state = None;
+                        None
+                    }
+                };
+                Ok(Reply::ReadDirFilesNth(reply::ReadDirFilesNth { data: maybe_data } ))
+            }
+
             Request::ReadDirFilesNext(_request) => {
                 let read_dir_files_state = ctx.read_dir_files_state.take();
 

src/store/certstore.rs

@@ -1,7 +1,4 @@
-use littlefs2::{
-    path,
-    path::{Path, PathBuf},
-};
+use littlefs2::{path, path::PathBuf};
 use rand_chacha::ChaCha8Rng;
 
 use crate::{

src/store/counterstore.rs

@@ -1,7 +1,4 @@
-use littlefs2::{
-    path,
-    path::{Path, PathBuf},
-};
+use littlefs2::{path, path::PathBuf};
 use rand_chacha::ChaCha8Rng;
 
 use crate::{