From b9d392e29d5f6b0f631cd01bf1b554484947f79e Mon Sep 17 00:00:00 2001
From: Thomas Coratger <60488569+tcoratger@users.noreply.github.com>
Date: Fri, 26 Jan 2024 05:57:33 +0100
Subject: [PATCH] small refactoring in `ethereum-forks` crate (#6234)

---
 crates/ethereum-forks/src/forkid.rs | 36 ++++++++++++++++++-----------
 crates/ethereum-forks/src/head.rs   |  6 +----
 2 files changed, 23 insertions(+), 19 deletions(-)

diff --git a/crates/ethereum-forks/src/forkid.rs b/crates/ethereum-forks/src/forkid.rs
index 39fa8a0c72..876d407db7 100644
--- a/crates/ethereum-forks/src/forkid.rs
+++ b/crates/ethereum-forks/src/forkid.rs
@@ -92,7 +92,7 @@ impl PartialOrd for ForkFilterKey {
 impl Ord for ForkFilterKey {
     fn cmp(&self, other: &Self) -> Ordering {
         match (self, other) {
-            (ForkFilterKey::Block(a), ForkFilterKey::Block(b)) => a.cmp(b),
+            (ForkFilterKey::Block(a), ForkFilterKey::Block(b)) |
             (ForkFilterKey::Time(a), ForkFilterKey::Time(b)) => a.cmp(b),
             (ForkFilterKey::Block(_), ForkFilterKey::Time(_)) => Ordering::Less,
             _ => Ordering::Greater,
@@ -194,6 +194,8 @@ impl ForkFilter {
                 ForkFilterKey::Block(_) => true,
                 ForkFilterKey::Time(time) => *time > genesis_timestamp,
             })
+            .collect::<BTreeSet<_>>()
+            .into_iter()
             .fold(
                 (BTreeMap::from([(ForkFilterKey::Block(0), genesis_fork_hash)]), genesis_fork_hash),
                 |(mut acc, base_hash), key| {
@@ -204,8 +206,10 @@ impl ForkFilter {
             )
             .0;
 
+        // Compute cache based on filtered forks and the current head.
         let cache = Cache::compute_cache(&forks, head);
 
+        // Create and return a new `ForkFilter`.
         Self { forks, head, cache }
     }
 
@@ -224,16 +228,14 @@ impl ForkFilter {
             head_in_past || head_in_future
         };
 
-        let mut transition = None;
-
         // recompute the cache
-        if recompute_cache {
+        let transition = if recompute_cache {
             let past = self.current();
-
             self.cache = Cache::compute_cache(&self.forks, head);
-
-            transition = Some(ForkTransition { current: self.current(), past })
-        }
+            Some(ForkTransition { current: self.current(), past })
+        } else {
+            None
+        };
 
         self.head = head;
 
@@ -347,19 +349,23 @@ struct Cache {
 impl Cache {
     /// Compute cache.
     fn compute_cache(forks: &BTreeMap<ForkFilterKey, ForkHash>, head: Head) -> Self {
+        // Prepare vectors to store past and future forks.
         let mut past = Vec::with_capacity(forks.len());
         let mut future = Vec::with_capacity(forks.len());
 
+        // Initialize variables to track the epoch range.
         let mut epoch_start = ForkFilterKey::Block(0);
         let mut epoch_end = None;
+
+        // Iterate through forks and categorize them into past and future.
         for (key, hash) in forks {
-            let active = if let ForkFilterKey::Block(block) = key {
-                *block <= head.number
-            } else if let ForkFilterKey::Time(time) = key {
-                *time <= head.timestamp
-            } else {
-                unreachable!()
+            // Check if the fork is active based on its type (Block or Time).
+            let active = match key {
+                ForkFilterKey::Block(block) => *block <= head.number,
+                ForkFilterKey::Time(time) => *time <= head.timestamp,
             };
+
+            // Categorize forks into past or future based on activity.
             if active {
                 epoch_start = *key;
                 past.push((*key, *hash));
@@ -371,11 +377,13 @@ impl Cache {
             }
         }
 
+        // Create ForkId using the last past fork's hash and the next epoch start.
         let fork_id = ForkId {
             hash: past.last().expect("there is always at least one - genesis - fork hash; qed").1,
             next: epoch_end.unwrap_or(ForkFilterKey::Block(0)).into(),
         };
 
+        // Return the computed cache.
         Self { epoch_start, epoch_end, past, future, fork_id }
     }
 }
diff --git a/crates/ethereum-forks/src/head.rs b/crates/ethereum-forks/src/head.rs
index 18bebed5fa..411853e0d3 100644
--- a/crates/ethereum-forks/src/head.rs
+++ b/crates/ethereum-forks/src/head.rs
@@ -44,11 +44,7 @@ impl Head {
         total_difficulty: U256,
         timestamp: u64,
     ) {
-        self.number = number;
-        self.hash = hash;
-        self.difficulty = difficulty;
-        self.total_difficulty = total_difficulty;
-        self.timestamp = timestamp;
+        *self = Self { number, hash, difficulty, total_difficulty, timestamp };
     }
 
     /// Checks if the head block is an empty block (i.e., has default values).