Redb slasher backend impl (#4529)

* initial redb impl

* redb impl

* remove phantom data

* fixed table definition

* fighting the borrow checker

* a rough draft that doesnt cause lifetime issues

* refactoring

* refactor

* refactor

* passing unit tests

* refactor

* refactor

* refactor

* commit

* move everything to one database

* remove panics, ready for a review

* merge

* a working redb impl

* passing a ref of txn to cursor

* this tries to create a second write transaction when initializing cursor. breaks everything

* Use 2 lifetimes and subtyping

Also fixes a bug in last_key caused by rev and next_back cancelling out

* Move table into cursor

* Merge remote-tracking branch 'origin/unstable' into redb-slasher-backend-impl

* changes based on feedback

* update lmdb

* fix lifetime issues

* moving everything from Cursor to Transaction

* update

* upgrade to redb 2.0

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into redb-slasher-backend-impl

* bring back cursor

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into redb-slasher-backend-impl

* fix delete while

* linting

* linting

* switch to lmdb

* update redb to v2.1

* build fixes, remove unwrap or default

* another build error

* hopefully this is the last build error

* fmt

* cargo.toml

* fix mdbx

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into redb-slasher-backend-impl

* Remove a collect

* Merge remote-tracking branch 'origin/unstable' into redb-slasher-backend-impl

* Merge branch 'redb-slasher-backend-impl' of https://github.com/eserilev/lighthouse into redb-slasher-backend-impl

* re-enable test

* fix failing slasher test

* Merge remote-tracking branch 'origin/unstable' into redb-slasher-backend-impl

* Rename DB file to `slasher.redb`

slasher/tests/attester_slashings.rs

@@ -1,4 +1,4 @@
-#![cfg(any(feature = "mdbx", feature = "lmdb"))]
+#![cfg(any(feature = "mdbx", feature = "lmdb", feature = "redb"))]
 
 use logging::test_logger;
 use maplit::hashset;

slasher/tests/backend.rs

@@ -1,4 +1,4 @@
-#![cfg(feature = "lmdb")]
+#![cfg(any(feature = "lmdb", feature = "redb"))]
 
 use slasher::{config::MDBX_DATA_FILENAME, Config, DatabaseBackend, DatabaseBackendOverride};
 use std::fs::File;
@@ -41,7 +41,7 @@ fn no_override_with_existing_mdbx_db() {
 }
 
 #[test]
-#[cfg(all(not(feature = "mdbx"), feature = "lmdb"))]
+#[cfg(all(not(feature = "mdbx"), feature = "lmdb", not(feature = "redb")))]
 fn failed_override_with_existing_mdbx_db() {
     let tempdir = tempdir().unwrap();
     let mut config = Config::new(tempdir.path().into());
@@ -55,3 +55,19 @@ fn failed_override_with_existing_mdbx_db() {
     );
     assert_eq!(config.backend, DatabaseBackend::Lmdb);
 }
+
+#[test]
+#[cfg(feature = "redb")]
+fn failed_override_with_existing_mdbx_db() {
+    let tempdir = tempdir().unwrap();
+    let mut config = Config::new(tempdir.path().into());
+
+    let filename = config.database_path.join(MDBX_DATA_FILENAME);
+    File::create(&filename).unwrap();
+
+    assert_eq!(
+        config.override_backend(),
+        DatabaseBackendOverride::Failure(filename)
+    );
+    assert_eq!(config.backend, DatabaseBackend::Redb);
+}

slasher/tests/proposer_slashings.rs

@@ -1,4 +1,4 @@
-#![cfg(any(feature = "mdbx", feature = "lmdb"))]
+#![cfg(any(feature = "mdbx", feature = "lmdb", feature = "redb"))]
 
 use logging::test_logger;
 use slasher::{

slasher/tests/random.rs

@@ -1,4 +1,4 @@
-#![cfg(any(feature = "mdbx", feature = "lmdb"))]
+#![cfg(any(feature = "mdbx", feature = "lmdb", feature = "redb"))]
 
 use logging::test_logger;
 use rand::prelude::*;

slasher/tests/wrap_around.rs

@@ -1,4 +1,4 @@
-#![cfg(any(feature = "mdbx", feature = "lmdb"))]
+#![cfg(any(feature = "mdbx", feature = "lmdb", feature = "redb"))]
 
 use logging::test_logger;
 use slasher::{