From cd4d812aca1f8a278f4ab694d97c1b81fa60ae06 Mon Sep 17 00:00:00 2001
From: Igor Katson <igor.katson@gmail.com>
Date: Tue, 20 Aug 2024 22:19:37 +0100
Subject: [PATCH] Restore Msb0 as Lsb0 is bugged - BEP 003 uses MSB

---
 crates/librqbit/src/bitv.rs            | 26 +++++++++++++-------------
 crates/librqbit/src/chunk_tracker.rs   |  6 ++----
 crates/librqbit/src/type_aliases.rs    |  6 ++++--
 crates/peer_binary_protocol/src/lib.rs |  4 ++--
 4 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/crates/librqbit/src/bitv.rs b/crates/librqbit/src/bitv.rs
index dedc6e7..f3c0129 100644
--- a/crates/librqbit/src/bitv.rs
+++ b/crates/librqbit/src/bitv.rs
@@ -3,15 +3,15 @@ use std::fs::File;
 use anyhow::Context;
 use bitvec::{
     boxed::BitBox,
-    order::Lsb0,
+    order::Msb0,
     slice::BitSlice,
     vec::BitVec,
     view::{AsBits, AsMutBits},
 };
 
 pub trait BitV: Send + Sync {
-    fn as_slice(&self) -> &BitSlice<u8, Lsb0>;
-    fn as_slice_mut(&mut self) -> &mut BitSlice<u8, Lsb0>;
+    fn as_slice(&self) -> &BitSlice<u8, Msb0>;
+    fn as_slice_mut(&mut self) -> &mut BitSlice<u8, Msb0>;
     fn into_dyn(self) -> Box<dyn BitV>;
     fn as_bytes(&self) -> &[u8];
     fn flush(&mut self) -> anyhow::Result<()>;
@@ -33,12 +33,12 @@ impl MmapBitV {
 }
 
 #[async_trait::async_trait]
-impl BitV for BitVec<u8, Lsb0> {
-    fn as_slice(&self) -> &BitSlice<u8, Lsb0> {
+impl BitV for BitVec<u8, Msb0> {
+    fn as_slice(&self) -> &BitSlice<u8, Msb0> {
         self.as_bitslice()
     }
 
-    fn as_slice_mut(&mut self) -> &mut BitSlice<u8, Lsb0> {
+    fn as_slice_mut(&mut self) -> &mut BitSlice<u8, Msb0> {
         self.as_mut_bitslice()
     }
 
@@ -56,12 +56,12 @@ impl BitV for BitVec<u8, Lsb0> {
 }
 
 #[async_trait::async_trait]
-impl BitV for BitBox<u8, Lsb0> {
-    fn as_slice(&self) -> &BitSlice<u8, Lsb0> {
+impl BitV for BitBox<u8, Msb0> {
+    fn as_slice(&self) -> &BitSlice<u8, Msb0> {
         self.as_bitslice()
     }
 
-    fn as_slice_mut(&mut self) -> &mut BitSlice<u8, Lsb0> {
+    fn as_slice_mut(&mut self) -> &mut BitSlice<u8, Msb0> {
         self.as_mut_bitslice()
     }
 
@@ -79,11 +79,11 @@ impl BitV for BitBox<u8, Lsb0> {
 }
 
 impl BitV for MmapBitV {
-    fn as_slice(&self) -> &BitSlice<u8, Lsb0> {
+    fn as_slice(&self) -> &BitSlice<u8, Msb0> {
         self.mmap.as_bits()
     }
 
-    fn as_slice_mut(&mut self) -> &mut BitSlice<u8, Lsb0> {
+    fn as_slice_mut(&mut self) -> &mut BitSlice<u8, Msb0> {
         self.mmap.as_mut_bits()
     }
 
@@ -101,11 +101,11 @@ impl BitV for MmapBitV {
 }
 
 impl BitV for Box<dyn BitV> {
-    fn as_slice(&self) -> &BitSlice<u8, Lsb0> {
+    fn as_slice(&self) -> &BitSlice<u8, Msb0> {
         (**self).as_slice()
     }
 
-    fn as_slice_mut(&mut self) -> &mut BitSlice<u8, Lsb0> {
+    fn as_slice_mut(&mut self) -> &mut BitSlice<u8, Msb0> {
         (**self).as_slice_mut()
     }
 
diff --git a/crates/librqbit/src/chunk_tracker.rs b/crates/librqbit/src/chunk_tracker.rs
index e113943..7c25458 100644
--- a/crates/librqbit/src/chunk_tracker.rs
+++ b/crates/librqbit/src/chunk_tracker.rs
@@ -425,10 +425,8 @@ impl ChunkTracker {
 
 #[cfg(test)]
 mod tests {
-    use std::collections::HashSet;
-
-    use bitvec::{order::Lsb0, vec::BitVec};
     use librqbit_core::{constants::CHUNK_SIZE, lengths::Lengths};
+    use std::collections::HashSet;
 
     use crate::{bitv::BitV, chunk_tracker::HaveNeededSelected, type_aliases::BF};
 
@@ -548,7 +546,7 @@ mod tests {
         ];
 
         let bf_len = l.piece_bitfield_bytes();
-        let initial_have: BitVec<u8, Lsb0> = BitVec::from_vec(vec![0u8; bf_len]);
+        let initial_have = BF::from_boxed_slice(vec![0u8; bf_len].into_boxed_slice());
         let initial_selected = BF::from_boxed_slice(vec![u8::MAX; bf_len].into_boxed_slice());
 
         // Initially, we need all files and all pieces.
diff --git a/crates/librqbit/src/type_aliases.rs b/crates/librqbit/src/type_aliases.rs
index 2f104e3..337ce8c 100644
--- a/crates/librqbit/src/type_aliases.rs
+++ b/crates/librqbit/src/type_aliases.rs
@@ -4,8 +4,10 @@ use futures::stream::BoxStream;
 
 use crate::{file_info::FileInfo, storage::TorrentStorage};
 
-pub type BS = bitvec::slice::BitSlice<u8, bitvec::order::Lsb0>;
-pub type BF = bitvec::boxed::BitBox<u8, bitvec::order::Lsb0>;
+// NOTE: Msb0 is used because that's what bittorrent protocol uses for bitfield.
+// Don't change to Lsb0 even though it might be a bit faster (in theory) on LE architectures.
+pub type BS = bitvec::slice::BitSlice<u8, bitvec::order::Msb0>;
+pub type BF = bitvec::boxed::BitBox<u8, bitvec::order::Msb0>;
 
 pub type PeerHandle = SocketAddr;
 pub type PeerStream = BoxStream<'static, SocketAddr>;
diff --git a/crates/peer_binary_protocol/src/lib.rs b/crates/peer_binary_protocol/src/lib.rs
index a6b2e7a..bd2d1a8 100644
--- a/crates/peer_binary_protocol/src/lib.rs
+++ b/crates/peer_binary_protocol/src/lib.rs
@@ -199,8 +199,8 @@ pub enum Message<ByteBuf: std::hash::Hash + Eq> {
 pub type MessageBorrowed<'a> = Message<ByteBuf<'a>>;
 pub type MessageOwned = Message<ByteBufOwned>;
 
-pub type BitfieldBorrowed<'a> = &'a bitvec::slice::BitSlice<u8, bitvec::order::Lsb0>;
-pub type BitfieldOwned = bitvec::vec::BitVec<u8, bitvec::order::Lsb0>;
+pub type BitfieldBorrowed<'a> = &'a bitvec::slice::BitSlice<u8, bitvec::order::Msb0>;
+pub type BitfieldOwned = bitvec::vec::BitVec<u8, bitvec::order::Msb0>;
 
 pub struct Bitfield<'a> {
     pub data: BitfieldBorrowed<'a>,