From 9bcecefbe072523ef2ba2291cba0c9f92236a000 Mon Sep 17 00:00:00 2001
From: Sergey Pepyakin <s.pepyakin@gmail.com>
Date: Sat, 28 Jul 2018 11:13:38 +0300
Subject: [PATCH] Iterate over overlay to decide which keys to purge (#436)
---
substrate/substrate/state-machine/src/ext.rs | 1 +
substrate/substrate/state-machine/src/lib.rs | 67 ++++++++++++++++++++
2 files changed, 68 insertions(+)
diff --git a/substrate/substrate/state-machine/src/ext.rs b/substrate/substrate/state-machine/src/ext.rs
index cd177b19845..5a8ba096f57 100644
--- a/substrate/substrate/state-machine/src/ext.rs
+++ b/substrate/substrate/state-machine/src/ext.rs
@@ -121,6 +121,7 @@ impl<'a, B: 'a> Externalities for Ext<'a, B>
fn clear_prefix(&mut self, prefix: &[u8]) {
self.mark_dirty();
+ self.overlay.clear_prefix(prefix);
self.backend.for_keys_with_prefix(prefix, |key| {
self.overlay.set_storage(key.to_vec(), None);
});
diff --git a/substrate/substrate/state-machine/src/lib.rs b/substrate/substrate/state-machine/src/lib.rs
index 5cc10027c62..17fd85852b6 100644
--- a/substrate/substrate/state-machine/src/lib.rs
+++ b/substrate/substrate/state-machine/src/lib.rs
@@ -68,10 +68,37 @@ impl OverlayedChanges {
.map(|x| x.as_ref().map(AsRef::as_ref))
}
+ /// Inserts the given key-value pair into the prospective change set.
+ ///
+ /// `None` can be used to delete a value specified by the given key.
fn set_storage(&mut self, key: Vec<u8>, val: Option<Vec<u8>>) {
self.prospective.insert(key, val);
}
+ /// Removes all key-value pairs which keys share the given prefix.
+ ///
+ /// NOTE that this doesn't take place immediately but written into the prospective
+ /// change set, and still can be reverted by [`discard_prospective`].
+ ///
+ /// [`discard_prospective`]: #method.discard_prospective
+ fn clear_prefix(&mut self, prefix: &[u8]) {
+ // Iterate over all prospective and mark all keys that share
+ // the given prefix as removed (None).
+ for (key, value) in self.prospective.iter_mut() {
+ if key.starts_with(prefix) {
+ *value = None;
+ }
+ }
+
+ // Then do the same with keys from commited changes.
+ // NOTE that we are making changes in the prospective change set.
+ for key in self.committed.keys() {
+ if key.starts_with(prefix) {
+ self.prospective.insert(key.to_owned(), None);
+ }
+ }
+ }
+
/// Discard prospective changes to state.
pub fn discard_prospective(&mut self) {
self.prospective.clear();
@@ -540,4 +567,44 @@ mod tests {
assert_eq!(remote_result, vec![66]);
assert_eq!(remote_result, local_result);
}
+
+ #[test]
+ fn clear_prefix_in_ext_works() {
+ let initial: HashMap<_, _> = map![
+ b"aaa".to_vec() => b"0".to_vec(),
+ b"abb".to_vec() => b"1".to_vec(),
+ b"abc".to_vec() => b"2".to_vec(),
+ b"bbb".to_vec() => b"3".to_vec()
+ ];
+ let backend = InMemory::from(initial).try_into_trie_backend().unwrap();
+ let mut overlay = OverlayedChanges {
+ committed: map![
+ b"aba".to_vec() => Some(b"1312".to_vec()),
+ b"bab".to_vec() => Some(b"228".to_vec())
+ ],
+ prospective: map![
+ b"abd".to_vec() => Some(b"69".to_vec()),
+ b"bbd".to_vec() => Some(b"42".to_vec())
+ ],
+ };
+
+ {
+ let mut ext = Ext::new(&mut overlay, &backend);
+ ext.clear_prefix(b"ab");
+ }
+ overlay.commit_prospective();
+
+ assert_eq!(
+ overlay.committed,
+ map![
+ b"abb".to_vec() => None,
+ b"abc".to_vec() => None,
+ b"aba".to_vec() => None,
+ b"abd".to_vec() => None,
+
+ b"bab".to_vec() => Some(b"228".to_vec()),
+ b"bbd".to_vec() => Some(b"42".to_vec())
+ ],
+ );
+ }
}
--
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