Centralize logic into fetch_sector_group

Cargo.lock

@@ -393,6 +393,15 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "higher-kinded-types"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "561985554c8b8d4808605c90a5f1979cc6c31a5d20b78465cd59501233c6678e"
+dependencies = [
+ "never-say-never",
+]
+
 [[package]]
 name = "hybrid-array"
 version = "0.2.1"
@@ -580,6 +589,12 @@ dependencies = [
  "adler2",
 ]
 
+[[package]]
+name = "never-say-never"
+version = "6.6.666"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf5a574dadd7941adeaa71823ecba5e28331b8313fb2e1c6a5c7e5981ea53ad6"
+
 [[package]]
 name = "nod"
 version = "2.0.0-alpha.1"
@@ -605,6 +620,7 @@ dependencies = [
  "memmap2",
  "miniz_oxide",
  "openssl",
+ "polonius-the-crab",
  "rand",
  "rayon",
  "sha1",
@@ -751,6 +767,16 @@ version = "0.3.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "953ec861398dccce10c670dfeaf3ec4911ca479e9c02154b3a215178c5f566f2"
 
+[[package]]
+name = "polonius-the-crab"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e97ca2c89572ae41bbec1c99498251f87dd5a94e500c5ec19c382dd593dd5ce9"
+dependencies = [
+ "higher-kinded-types",
+ "never-say-never",
+]
+
 [[package]]
 name = "portable-atomic"
 version = "1.9.0"

nod/Cargo.toml

@@ -45,6 +45,7 @@ md-5 = { workspace = true }
 memmap2 = "0.9"
 miniz_oxide = { version = "0.8", optional = true }
 openssl = { version = "0.10", optional = true }
+polonius-the-crab = "0.4"
 rand = "0.8"
 rayon = "1.10"
 sha1 = { workspace = true }

nod/src/disc/gcn.rs

@@ -9,7 +9,7 @@ use zerocopy::FromBytes;
 
 use crate::{
     disc::{
-        preloader::{Preloader, SectorGroup, SectorGroupRequest},
+        preloader::{fetch_sector_group, Preloader, SectorGroup, SectorGroupRequest},
         ApploaderHeader, DiscHeader, DolHeader, PartitionHeader, BI2_SIZE, BOOT_SIZE,
         SECTOR_GROUP_SIZE, SECTOR_SIZE,
     },
@@ -77,14 +77,9 @@ impl BufRead for PartitionReaderGC {
             mode: PartitionEncryption::Original,
         };
 
-        let sector_group = if matches!(&self.sector_group, Some(sector_group) if sector_group.request == request)
+        // Load sector group
-        {
+        let (sector_group, _updated) =
-            // We can improve this in Rust 2024 with `if_let_rescope`
+            fetch_sector_group(request, max_groups, &mut self.sector_group, &self.preloader)?;
-            // https://github.com/rust-lang/rust/issues/124085
-            self.sector_group.as_ref().unwrap()
-        } else {
-            self.sector_group.insert(self.preloader.fetch(request, max_groups)?)
-        };
 
         // Calculate the number of consecutive sectors in the group
         let group_sector = abs_sector - abs_group_sector;
@@ -146,18 +141,9 @@ pub(crate) fn read_dol(
     let mut raw_dol: Vec<u8> =
         read_vec(reader, size_of::<DolHeader>()).context("Reading DOL header")?;
     let dol_header = DolHeader::ref_from_bytes(raw_dol.as_slice()).unwrap();
-    let dol_size = dol_header
+    let dol_size = (dol_header.text_offs.iter().zip(&dol_header.text_sizes))
-        .text_offs
+        .chain(dol_header.data_offs.iter().zip(&dol_header.data_sizes))
-        .iter()
-        .zip(&dol_header.text_sizes)
         .map(|(offs, size)| offs.get() + size.get())
-        .chain(
-            dol_header
-                .data_offs
-                .iter()
-                .zip(&dol_header.data_sizes)
-                .map(|(offs, size)| offs.get() + size.get()),
-        )
         .max()
         .unwrap_or(size_of::<DolHeader>() as u32);
     raw_dol.resize(dol_size as usize, 0);
@@ -203,12 +189,10 @@ pub(crate) fn read_part_meta(
     let mut raw_apploader: Vec<u8> =
         read_vec(reader, size_of::<ApploaderHeader>()).context("Reading apploader header")?;
     let apploader_header = ApploaderHeader::ref_from_bytes(raw_apploader.as_slice()).unwrap();
-    raw_apploader.resize(
+    let apploader_size = size_of::<ApploaderHeader>()
-        size_of::<ApploaderHeader>()
         + apploader_header.size.get() as usize
-            + apploader_header.trailer_size.get() as usize,
+        + apploader_header.trailer_size.get() as usize;
-        0,
+    raw_apploader.resize(apploader_size, 0);
-    );
     reader
         .read_exact(&mut raw_apploader[size_of::<ApploaderHeader>()..])
         .context("Reading apploader")?;

nod/src/disc/preloader.rs

@@ -11,6 +11,7 @@ use bytes::{Bytes, BytesMut};
 use crossbeam_channel::{Receiver, Sender};
 use crossbeam_utils::sync::WaitGroup;
 use lru::LruCache;
+use polonius_the_crab::{polonius, polonius_return};
 use simple_moving_average::{SingleSumSMA, SMA};
 use tracing::{debug, error, instrument, span, Level};
 use zerocopy::FromZeros;
@@ -556,3 +557,22 @@ impl SectorGroupLoader {
         Ok((sector_bitmap, io_duration))
     }
 }
+
+/// Fetch a sector group from the cache or from the preloader.
+/// Returns a boolean indicating if the group was updated.
+pub fn fetch_sector_group<'a>(
+    request: SectorGroupRequest,
+    max_groups: u32,
+    mut cached: &'a mut Option<SectorGroup>,
+    preloader: &Preloader,
+) -> io::Result<(&'a SectorGroup, bool)> {
+    polonius!(|cached| -> io::Result<(&'polonius SectorGroup, bool)> {
+        if let Some(sector_group) = cached {
+            if sector_group.request == request {
+                polonius_return!(Ok((sector_group, false)));
+            }
+        }
+    });
+    let sector_group = preloader.fetch(request, max_groups)?;
+    Ok((cached.insert(sector_group), true))
+}

nod/src/disc/reader.rs

@@ -14,7 +14,9 @@ use crate::{
         direct::{DirectDiscReader, DirectDiscReaderMode},
         fst::{Fst, NodeKind},
         gcn::{read_fst, PartitionReaderGC},
-        preloader::{Preloader, SectorGroup, SectorGroupLoader, SectorGroupRequest},
+        preloader::{
+            fetch_sector_group, Preloader, SectorGroup, SectorGroupLoader, SectorGroupRequest,
+        },
         wii::{
             PartitionReaderWii, WiiPartEntry, WiiPartGroup, WiiPartitionHeader, REGION_OFFSET,
             REGION_SIZE, WII_PART_GROUP_OFF,
@@ -32,6 +34,7 @@ use crate::{
 
 pub struct DiscReader {
     io: Box<dyn BlockReader>,
+    preloader: Arc<Preloader>,
     pos: u64,
     size: u64,
     mode: PartitionEncryption,
@@ -39,7 +42,6 @@ pub struct DiscReader {
     partitions: Arc<[PartitionInfo]>,
     region: Option<[u8; REGION_SIZE]>,
     sector_group: Option<SectorGroup>,
-    preloader: Arc<Preloader>,
     alt_disc_header: Option<Arc<DiscHeader>>,
     alt_partitions: Option<Arc<[PartitionInfo]>>,
 }
@@ -48,6 +50,7 @@ impl Clone for DiscReader {
     fn clone(&self) -> Self {
         Self {
             io: self.io.clone(),
+            preloader: self.preloader.clone(),
             pos: 0,
             size: self.size,
             mode: self.mode,
@@ -55,7 +58,6 @@ impl Clone for DiscReader {
             partitions: self.partitions.clone(),
             region: self.region,
             sector_group: None,
-            preloader: self.preloader.clone(),
             alt_disc_header: self.alt_disc_header.clone(),
             alt_partitions: self.alt_partitions.clone(),
         }
@@ -124,6 +126,7 @@ impl DiscReader {
         );
         Ok(Self {
             io,
+            preloader,
             pos: 0,
             size,
             mode: options.partition_encryption,
@@ -131,7 +134,6 @@ impl DiscReader {
             partitions,
             region,
             sector_group: None,
-            preloader,
             alt_disc_header,
             alt_partitions,
         })
@@ -246,14 +248,8 @@ impl DiscReader {
         };
 
         // Load sector group
-        let sector_group = if matches!(&self.sector_group, Some(sector_group) if sector_group.request == request)
+        let (sector_group, _updated) =
-        {
+            fetch_sector_group(request, max_groups, &mut self.sector_group, &self.preloader)?;
-            // We can improve this in Rust 2024 with `if_let_rescope`
-            // https://github.com/rust-lang/rust/issues/124085
-            self.sector_group.as_ref().unwrap()
-        } else {
-            self.sector_group.insert(self.preloader.fetch(request, max_groups)?)
-        };
 
         // Calculate the number of consecutive sectors in the group
         let group_sector = abs_sector - abs_group_sector;
@@ -307,14 +303,8 @@ impl BufRead for DiscReader {
         };
 
         // Load sector group
-        let sector_group = if matches!(&self.sector_group, Some(sector_group) if sector_group.request == request)
+        let (sector_group, _updated) =
-        {
+            fetch_sector_group(request, max_groups, &mut self.sector_group, &self.preloader)?;
-            // We can improve this in Rust 2024 with `if_let_rescope`
-            // https://github.com/rust-lang/rust/issues/124085
-            self.sector_group.as_ref().unwrap()
-        } else {
-            self.sector_group.insert(self.preloader.fetch(request, max_groups)?)
-        };
 
         // Calculate the number of consecutive sectors in the group
         let group_sector = abs_sector - abs_group_sector;

nod/src/disc/wii.rs

@@ -15,7 +15,7 @@ use crate::{
     disc::{
         gcn::{read_part_meta, PartitionReaderGC},
         hashes::sha1_hash,
-        preloader::{Preloader, SectorGroup, SectorGroupRequest},
+        preloader::{fetch_sector_group, Preloader, SectorGroup, SectorGroupRequest},
         SECTOR_GROUP_SIZE, SECTOR_SIZE,
     },
     io::block::BlockReader,
@@ -378,14 +378,11 @@ impl BufRead for PartitionReaderWii {
                 PartitionEncryption::ForceDecryptedNoHashes
             },
         };
-        let sector_group = if matches!(&self.sector_group, Some(sector_group) if sector_group.request == request)
+
-        {
+        // Load sector group
-            // We can improve this in Rust 2024 with `if_let_rescope`
+        let (sector_group, updated) =
-            // https://github.com/rust-lang/rust/issues/124085
+            fetch_sector_group(request, max_groups, &mut self.sector_group, &self.preloader)?;
-            self.sector_group.as_ref().unwrap()
+        if updated && self.options.validate_hashes {
-        } else {
-            let sector_group = self.preloader.fetch(request, max_groups)?;
-            if self.options.validate_hashes {
             if let Some(h3_table) = self.meta.as_ref().and_then(|m| m.raw_h3_table.as_deref()) {
                 verify_hashes(
                     array_ref![sector_group.data, 0, SECTOR_GROUP_SIZE],
@@ -394,8 +391,6 @@ impl BufRead for PartitionReaderWii {
                 )?;
             }
         }
-            self.sector_group.insert(sector_group)
-        };
 
         // Read from sector group buffer
         let consecutive_sectors = sector_group.consecutive_sectors(group_sector);