cleanup(db): Give forward and reverse database iterators explicit names (#8063)

* Give forward and reverse database iterators explicit names

* clippy: Ignore large error variants

.cargo/config.toml

@@ -56,6 +56,9 @@ rustflags = [
     "-Wmissing_docs",
 
     # TODOs:
+    # Fix this lint eventually.
+    "-Aclippy::result_large_err",
+
     # `cargo fix` might help do these fixes,
     # or add a config.toml to sub-directories which should allow these lints,
     # or try allowing the lint in the specific module (lib.rs doesn't seem to work in some cases)

zebra-state/src/service/finalized_state/disk_db.rs

@@ -156,7 +156,7 @@ impl WriteDisk for DiskWriteBatch {
     }
 
     // TODO: convert zs_delete_range() to take std::ops::RangeBounds
-    //       see zs_range_iter() for an example of the edge cases
+    //       see zs_forward_range_iter() for an example of the edge cases
     fn zs_delete_range<C, K>(&mut self, cf: &C, from: K, to: K)
     where
         C: rocksdb::AsColumnFamilyRef,
@@ -329,7 +329,7 @@ impl ReadDisk for DiskDb {
         V: FromDisk,
     {
         // Reading individual values from iterators does not seem to cause database hangs.
-        self.zs_range_iter(cf, .., false).next()
+        self.zs_forward_range_iter(cf, ..).next()
     }
 
     #[allow(clippy::unwrap_in_result)]
@@ -340,7 +340,7 @@ impl ReadDisk for DiskDb {
         V: FromDisk,
     {
         // Reading individual values from iterators does not seem to cause database hangs.
-        self.zs_range_iter(cf, .., true).next()
+        self.zs_reverse_range_iter(cf, ..).next()
     }
 
     #[allow(clippy::unwrap_in_result)]
@@ -351,7 +351,7 @@ impl ReadDisk for DiskDb {
         V: FromDisk,
     {
         // Reading individual values from iterators does not seem to cause database hangs.
-        self.zs_range_iter(cf, lower_bound.., false).next()
+        self.zs_forward_range_iter(cf, lower_bound..).next()
     }
 
     #[allow(clippy::unwrap_in_result)]
@@ -362,7 +362,7 @@ impl ReadDisk for DiskDb {
         V: FromDisk,
     {
         // Reading individual values from iterators does not seem to cause database hangs.
-        self.zs_range_iter(cf, ..=upper_bound, true).next()
+        self.zs_reverse_range_iter(cf, ..=upper_bound).next()
     }
 
     fn zs_items_in_range_ordered<C, K, V, R>(&self, cf: &C, range: R) -> BTreeMap<K, V>
@@ -372,7 +372,7 @@ impl ReadDisk for DiskDb {
         V: FromDisk,
         R: RangeBounds<K>,
     {
-        self.zs_range_iter(cf, range, false).collect()
+        self.zs_forward_range_iter(cf, range).collect()
     }
 
     fn zs_items_in_range_unordered<C, K, V, R>(&self, cf: &C, range: R) -> HashMap<K, V>
@@ -382,7 +382,7 @@ impl ReadDisk for DiskDb {
         V: FromDisk,
         R: RangeBounds<K>,
     {
-        self.zs_range_iter(cf, range, false).collect()
+        self.zs_forward_range_iter(cf, range).collect()
     }
 }
 
@@ -402,18 +402,13 @@ impl DiskWriteBatch {
 }
 
 impl DiskDb {
-    /// Returns an iterator over the items in `cf` in `range`.
-    ///
-    /// Accepts a `reverse` argument. If it is `true`, creates the iterator with an
-    /// [`IteratorMode`](rocksdb::IteratorMode) of [`End`](rocksdb::IteratorMode::End), or
-    /// [`From`](rocksdb::IteratorMode::From) with [`Direction::Reverse`](rocksdb::Direction::Reverse).
+    /// Returns a forward iterator over the items in `cf` in `range`.
     ///
     /// Holding this iterator open might delay block commit transactions.
-    pub fn zs_range_iter<C, K, V, R>(
+    pub fn zs_forward_range_iter<C, K, V, R>(
         &self,
         cf: &C,
         range: R,
-        reverse: bool,
     ) -> impl Iterator<Item = (K, V)> + '_
     where
         C: rocksdb::AsColumnFamilyRef,
@@ -421,14 +416,12 @@ impl DiskDb {
         V: FromDisk,
         R: RangeBounds<K>,
     {
-        self.zs_range_iter_with_direction(cf, range, reverse)
+        self.zs_range_iter_with_direction(cf, range, false)
     }
 
     /// Returns a reverse iterator over the items in `cf` in `range`.
     ///
     /// Holding this iterator open might delay block commit transactions.
-    ///
-    /// This code is copied from `zs_range_iter()`, but with the mode reversed.
     pub fn zs_reverse_range_iter<C, K, V, R>(
         &self,
         cf: &C,

zebra-state/src/service/finalized_state/disk_format/transparent.rs

@@ -420,13 +420,13 @@ impl AddressTransaction {
     /// address. Starts at the first UTXO, or at the `query` start height, whichever is greater.
     /// Ends at the maximum possible transaction index for the end height.
     ///
-    /// Used to look up transactions with [`DiskDb::zs_range_iter`][1].
+    /// Used to look up transactions with [`DiskDb::zs_forward_range_iter`][1].
     ///
     /// The transaction locations in the:
     /// - start bound might be invalid, if it is based on the `query` start height.
     /// - end bound will always be invalid.
     ///
-    /// But this is not an issue, since [`DiskDb::zs_range_iter`][1] will fetch all existing
+    /// But this is not an issue, since [`DiskDb::zs_forward_range_iter`][1] will fetch all existing
     /// (valid) values in the range.
     ///
     /// [1]: super::super::disk_db::DiskDb

zebra-state/src/service/finalized_state/zebra_db/chain.rs

@@ -78,7 +78,7 @@ impl ZebraDb {
     ) -> impl Iterator<Item = (RawBytes, Arc<HistoryTree>)> + '_ {
         let history_tree_cf = self.db.cf_handle("history_tree").unwrap();
 
-        self.db.zs_range_iter(&history_tree_cf, .., false)
+        self.db.zs_forward_range_iter(&history_tree_cf, ..)
     }
 
     // Value pool methods

zebra-state/src/service/finalized_state/zebra_db/shielded.rs

@@ -155,7 +155,7 @@ impl ZebraDb {
         &self,
     ) -> impl Iterator<Item = (RawBytes, Arc<sprout::tree::NoteCommitmentTree>)> + '_ {
         let sprout_trees = self.db.cf_handle("sprout_note_commitment_tree").unwrap();
-        self.db.zs_range_iter(&sprout_trees, .., false)
+        self.db.zs_forward_range_iter(&sprout_trees, ..)
     }
 
     // # Sapling trees
@@ -209,7 +209,7 @@ impl ZebraDb {
         R: std::ops::RangeBounds<Height>,
     {
         let sapling_trees = self.db.cf_handle("sapling_note_commitment_tree").unwrap();
-        self.db.zs_range_iter(&sapling_trees, range, false)
+        self.db.zs_forward_range_iter(&sapling_trees, range)
     }
 
     /// Returns the Sapling note commitment trees in the reversed range, in decreasing height order.
@@ -259,7 +259,7 @@ impl ZebraDb {
             .unwrap();
 
         self.db
-            .zs_range_iter(&sapling_subtrees, range, false)
+            .zs_forward_range_iter(&sapling_subtrees, range)
             .collect()
     }
 
@@ -335,7 +335,7 @@ impl ZebraDb {
         R: std::ops::RangeBounds<Height>,
     {
         let orchard_trees = self.db.cf_handle("orchard_note_commitment_tree").unwrap();
-        self.db.zs_range_iter(&orchard_trees, range, false)
+        self.db.zs_forward_range_iter(&orchard_trees, range)
     }
 
     /// Returns the Orchard note commitment trees in the reversed range, in decreasing height order.
@@ -385,7 +385,7 @@ impl ZebraDb {
             .unwrap();
 
         self.db
-            .zs_range_iter(&orchard_subtrees, range, false)
+            .zs_forward_range_iter(&orchard_subtrees, range)
             .collect()
     }
 

zebra-state/src/service/finalized_state/zebra_db/transparent.rs

@@ -242,11 +242,7 @@ impl ZebraDb {
             AddressTransaction::address_iterator_range(address_location, query_height_range);
 
         self.db
-            .zs_range_iter(
-                &tx_loc_by_transparent_addr_loc,
-                transaction_location_range,
-                false,
-            )
+            .zs_forward_range_iter(&tx_loc_by_transparent_addr_loc, transaction_location_range)
             .map(|(tx_loc, ())| tx_loc)
             .collect()
     }