From e68d3b9e63914c1008e1a4bb20a847428659d52e Mon Sep 17 00:00:00 2001
From: KaFai Choi <kafai@river.com>
Date: Wed, 23 Mar 2022 10:58:05 +0700
Subject: [PATCH 1/2] remove Database::flush

---
 CHANGELOG.md             | 1 +
 src/database/any.rs      | 4 ----
 src/database/keyvalue.rs | 4 ----
 src/database/memory.rs   | 4 ----
 src/database/mod.rs      | 7 -------
 src/database/sqlite.rs   | 4 ----
 6 files changed, 1 insertion(+), 23 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7eaf9bff..97fac266 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -52,6 +52,7 @@ To decouple the `Wallet` from the `Blockchain` we've made major changes:
 - Stop making a request for the block height when calling `Wallet:new`.
 - Added `SyncOptions` to capture extra (future) arguments to `Wallet::sync`.
 - Removed `max_addresses` sync parameter which determined how many addresses to cache before syncing since this can just be done with `ensure_addresses_cached`.
+- remove `flush` method from the `Database` trait.
 
 ## [v0.16.1] - [v0.16.0]
 
diff --git a/src/database/any.rs b/src/database/any.rs
index b370ded9..bbd9d41a 100644
--- a/src/database/any.rs
+++ b/src/database/any.rs
@@ -255,10 +255,6 @@ impl Database for AnyDatabase {
     fn increment_last_index(&mut self, keychain: KeychainKind) -> Result<u32, Error> {
         impl_inner_method!(AnyDatabase, self, increment_last_index, keychain)
     }
-
-    fn flush(&mut self) -> Result<(), Error> {
-        impl_inner_method!(AnyDatabase, self, flush)
-    }
 }
 
 impl BatchOperations for AnyBatch {
diff --git a/src/database/keyvalue.rs b/src/database/keyvalue.rs
index 5baa6c86..c298be36 100644
--- a/src/database/keyvalue.rs
+++ b/src/database/keyvalue.rs
@@ -402,10 +402,6 @@ impl Database for Tree {
             Ok(val)
         })
     }
-
-    fn flush(&mut self) -> Result<(), Error> {
-        Ok(Tree::flush(self).map(|_| ())?)
-    }
 }
 
 impl BatchDatabase for Tree {
diff --git a/src/database/memory.rs b/src/database/memory.rs
index 1c8d1cca..4256d217 100644
--- a/src/database/memory.rs
+++ b/src/database/memory.rs
@@ -449,10 +449,6 @@ impl Database for MemoryDatabase {
 
         Ok(*value)
     }
-
-    fn flush(&mut self) -> Result<(), Error> {
-        Ok(())
-    }
 }
 
 impl BatchDatabase for MemoryDatabase {
diff --git a/src/database/mod.rs b/src/database/mod.rs
index 80e5a2a5..c7ff1795 100644
--- a/src/database/mod.rs
+++ b/src/database/mod.rs
@@ -158,13 +158,6 @@ pub trait Database: BatchOperations {
     ///
     /// It should insert and return `0` if not present in the database
     fn increment_last_index(&mut self, keychain: KeychainKind) -> Result<u32, Error>;
-
-    #[deprecated(
-        since = "0.18.0",
-        note = "The flush function is only needed for the sled database on mobile, instead for mobile use the sqlite database."
-    )]
-    /// Force changes to be written to disk
-    fn flush(&mut self) -> Result<(), Error>;
 }
 
 /// Trait for a database that supports batch operations
diff --git a/src/database/sqlite.rs b/src/database/sqlite.rs
index fbdf1ad6..06ed7e43 100644
--- a/src/database/sqlite.rs
+++ b/src/database/sqlite.rs
@@ -891,10 +891,6 @@ impl Database for SqliteDatabase {
             }
         }
     }
-
-    fn flush(&mut self) -> Result<(), Error> {
-        Ok(())
-    }
 }
 
 impl BatchDatabase for SqliteDatabase {

From 5ff8320e3b1cb4e3971549a3e3c168f20762d04b Mon Sep 17 00:00:00 2001
From: KaFai Choi <kafai@river.com>
Date: Wed, 23 Mar 2022 13:46:16 +0700
Subject: [PATCH 2/2] add private function ivcec_to_u32 in keyvalue

---
 src/database/keyvalue.rs | 42 ++++++++++++++--------------------------
 1 file changed, 14 insertions(+), 28 deletions(-)

diff --git a/src/database/keyvalue.rs b/src/database/keyvalue.rs
index c298be36..e10ada1f 100644
--- a/src/database/keyvalue.rs
+++ b/src/database/keyvalue.rs
@@ -166,16 +166,9 @@ macro_rules! impl_batch_operations {
         fn del_last_index(&mut self, keychain: KeychainKind) -> Result<Option<u32>, Error> {
             let key = MapKey::LastIndex(keychain).as_map_key();
             let res = self.remove(key);
-            let res = $process_delete!(res);
-
-            match res {
-                None => Ok(None),
-                Some(b) => {
-                    let array: [u8; 4] = b.as_ref().try_into().map_err(|_| Error::InvalidU32Bytes(b.to_vec()))?;
-                    let val = u32::from_be_bytes(array);
-                    Ok(Some(val))
-                }
-            }
+            $process_delete!(res)
+            .map(ivec_to_u32)
+            .transpose()
         }
 
         fn del_sync_time(&mut self) -> Result<Option<SyncTime>, Error> {
@@ -357,16 +350,7 @@ impl Database for Tree {
 
     fn get_last_index(&self, keychain: KeychainKind) -> Result<Option<u32>, Error> {
         let key = MapKey::LastIndex(keychain).as_map_key();
-        self.get(key)?
-            .map(|b| -> Result<_, Error> {
-                let array: [u8; 4] = b
-                    .as_ref()
-                    .try_into()
-                    .map_err(|_| Error::InvalidU32Bytes(b.to_vec()))?;
-                let val = u32::from_be_bytes(array);
-                Ok(val)
-            })
-            .transpose()
+        self.get(key)?.map(ivec_to_u32).transpose()
     }
 
     fn get_sync_time(&self) -> Result<Option<SyncTime>, Error> {
@@ -393,17 +377,19 @@ impl Database for Tree {
 
             Some(new.to_be_bytes().to_vec())
         })?
-        .map_or(Ok(0), |b| -> Result<_, Error> {
-            let array: [u8; 4] = b
-                .as_ref()
-                .try_into()
-                .map_err(|_| Error::InvalidU32Bytes(b.to_vec()))?;
-            let val = u32::from_be_bytes(array);
-            Ok(val)
-        })
+        .map_or(Ok(0), ivec_to_u32)
     }
 }
 
+fn ivec_to_u32(b: sled::IVec) -> Result<u32, Error> {
+    let array: [u8; 4] = b
+        .as_ref()
+        .try_into()
+        .map_err(|_| Error::InvalidU32Bytes(b.to_vec()))?;
+    let val = u32::from_be_bytes(array);
+    Ok(val)
+}
+
 impl BatchDatabase for Tree {
     type Batch = sled::Batch;