From abd7f6b090c92bd6fd315a7abfdff6b6f4b931fc Mon Sep 17 00:00:00 2001
From: carllin <wumu727@gmail.com>
Date: Wed, 15 May 2019 18:28:23 -0700
Subject: [PATCH] Change slot_meta_iterator() to return an iterator not a
 cursor (#4303)

automerge
---
 core/src/blocktree.rs      | 16 ++++++++++------
 core/src/repair_service.rs | 10 +++++-----
 2 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/core/src/blocktree.rs b/core/src/blocktree.rs
index b4faccad39..0d00c9d6de 100644
--- a/core/src/blocktree.rs
+++ b/core/src/blocktree.rs
@@ -1,7 +1,6 @@
 //! The `block_tree` module provides functions for parallel verification of the
 //! Proof of History ledger as well as iterative read, append write, and random
 //! access read to a persistent file-based ledger.
-
 use crate::entry::Entry;
 use crate::erasure::{self, Session};
 use crate::packet::{Blob, SharedBlob, BLOB_HEADER_SIZE};
@@ -47,7 +46,7 @@ macro_rules! db_imports {
         pub use db::columns;
 
         pub type Database = db::Database<$db>;
-        pub type Cursor<C>  = db::Cursor<$db, C>;
+        pub type Cursor<C> = db::Cursor<$db, C>;
         pub type LedgerColumn<C> = db::LedgerColumn<$db, C>;
         pub type WriteBatch = db::WriteBatch<$db>;
         type BatchProcessor = db::BatchProcessor<$db>;
@@ -183,10 +182,15 @@ impl Blocktree {
         self.orphans_cf.get(slot)
     }
 
-    pub fn slot_meta_iterator(&self, slot: u64) -> Result<Cursor<cf::SlotMeta>> {
-        let mut db_iterator = self.db.cursor::<cf::SlotMeta>()?;
-        db_iterator.seek(slot);
-        Ok(db_iterator)
+    pub fn slot_meta_iterator(&self, slot: u64) -> Result<impl Iterator<Item = (u64, SlotMeta)>> {
+        let meta_iter = self.db.iter::<cf::SlotMeta>(Some(slot))?;
+        Ok(meta_iter.map(|(slot, slot_meta_bytes)| {
+            (
+                slot,
+                deserialize(&slot_meta_bytes)
+                    .unwrap_or_else(|_| panic!("Could not deserialize SlotMeta for slot {}", slot)),
+            )
+        }))
     }
 
     pub fn slot_data_iterator(
diff --git a/core/src/repair_service.rs b/core/src/repair_service.rs
index 8b34f99e4f..3d7dc7cc91 100644
--- a/core/src/repair_service.rs
+++ b/core/src/repair_service.rs
@@ -285,17 +285,17 @@ impl RepairService {
         let last_confirmed_epoch = epoch_schedule.get_stakers_epoch(root);
         let last_epoch_slot = epoch_schedule.get_last_slot_in_epoch(last_confirmed_epoch);
 
-        let mut meta_iter = blocktree
+        let meta_iter = blocktree
             .slot_meta_iterator(root + 1)
             .expect("Couldn't get db iterator");
 
-        while meta_iter.valid() && meta_iter.key().unwrap() <= last_epoch_slot {
-            let current_slot = meta_iter.key().unwrap();
-            let meta = meta_iter.value().unwrap();
+        for (current_slot, meta) in meta_iter {
+            if current_slot > last_epoch_slot {
+                break;
+            }
             if meta.is_full() {
                 slots_in_gossip.insert(current_slot);
             }
-            meta_iter.next();
         }
     }