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Frame-support storage: make iterations and translate consistent #5470

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Sep 15, 2020
Merged

Frame-support storage: make iterations and translate consistent #5470

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42c73f7
implementation and factorisation
gui1117 Sep 9, 2020
fed1fda
factorize test
gui1117 Sep 9, 2020
3b5b4b0
doc
gui1117 Sep 9, 2020
bf25dd0
fix bug and improve test
gui1117 Sep 9, 2020
8e41aa8
address suggestions
gui1117 Sep 10, 2020
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149 changes: 79 additions & 70 deletions frame/support/src/storage/generator/double_map.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@
use sp_std::prelude::*;
use sp_std::borrow::Borrow;
use codec::{FullCodec, FullEncode, Decode, Encode, EncodeLike};
use crate::{storage::{self, unhashed, StorageAppend}, Never};
use crate::{storage::{self, unhashed, StorageAppend, PrefixIterator}, Never};
use crate::hash::{StorageHasher, Twox128, ReversibleStorageHasher};

/// Generator for `StorageDoubleMap` used by `decl_storage`.
Expand Down Expand Up @@ -213,10 +213,11 @@ impl<K1, K2, V, G> storage::StorageDoubleMap<K1, K2, V> for G where
KArg1: ?Sized + EncodeLike<K1>
{
let prefix = Self::storage_double_map_final_key1(k1);
storage::PrefixIterator::<V> {
storage::PrefixIterator {
prefix: prefix.clone(),
previous_key: prefix,
phantom_data: Default::default(),
drain: false,
closure: |_raw_key, mut raw_value| V::decode(&mut raw_value),
}
}

Expand Down Expand Up @@ -322,54 +323,6 @@ impl<K1, K2, V, G> storage::StorageDoubleMap<K1, K2, V> for G where
}
}

/// Iterate over a prefix and decode raw_key and raw_value into `T`.
pub struct MapIterator<T> {
prefix: Vec<u8>,
previous_key: Vec<u8>,
/// If true then value are removed while iterating
drain: bool,
/// Function that take `(raw_key_without_prefix, raw_value)` and decode `T`.
/// `raw_key_without_prefix` is the raw storage key without the prefix iterated on.
closure: fn(&[u8], &[u8]) -> Result<T, codec::Error>,
}

impl<T> Iterator for MapIterator<T> {
type Item = T;

fn next(&mut self) -> Option<Self::Item> {
loop {
let maybe_next = sp_io::storage::next_key(&self.previous_key)
.filter(|n| n.starts_with(&self.prefix));
break match maybe_next {
Some(next) => {
self.previous_key = next;
let raw_value = match unhashed::get_raw(&self.previous_key) {
Some(raw_value) => raw_value,
None => {
frame_support::print("ERROR: next_key returned a key with no value in MapIterator");
continue
}
};
if self.drain {
unhashed::kill(&self.previous_key)
}
let raw_key_without_prefix = &self.previous_key[self.prefix.len()..];
let item = match (self.closure)(raw_key_without_prefix, &raw_value[..]) {
Ok(item) => item,
Err(_e) => {
frame_support::print("ERROR: (key, value) failed to decode in MapIterator");
continue
}
};

Some(item)
}
None => None,
}
}
}
}

impl<
K1: FullCodec,
K2: FullCodec,
Expand All @@ -379,8 +332,8 @@ impl<
G::Hasher1: ReversibleStorageHasher,
G::Hasher2: ReversibleStorageHasher
{
type PrefixIterator = MapIterator<(K2, V)>;
type Iterator = MapIterator<(K1, K2, V)>;
type PrefixIterator = PrefixIterator<(K2, V)>;
type Iterator = PrefixIterator<(K1, K2, V)>;

fn iter_prefix(k1: impl EncodeLike<K1>) -> Self::PrefixIterator {
let prefix = G::storage_double_map_final_key1(k1);
Expand Down Expand Up @@ -423,20 +376,41 @@ impl<
iterator
}

fn translate<O: Decode, F: Fn(O) -> Option<V>>(f: F) {
fn translate<O: Decode, F: Fn(K1, K2, O) -> Option<V>>(f: F) {
let prefix = G::prefix_hash();
let mut previous_key = prefix.clone();
loop {
match sp_io::storage::next_key(&previous_key).filter(|n| n.starts_with(&prefix)) {
Some(next) => {
previous_key = next;
let maybe_value = unhashed::get::<O>(&previous_key);
match maybe_value {
Some(value) => match f(value) {
Some(new) => unhashed::put::<V>(&previous_key, &new),
None => unhashed::kill(&previous_key),
let value = match unhashed::get::<O>(&previous_key) {
Some(value) => value,
None => {
crate::debug::error!("Invalid translate: fail to decode old value");
continue
},
};
let mut key_material = G::Hasher1::reverse(&previous_key[prefix.len()..]);
let key1 = match K1::decode(&mut key_material) {
Ok(key1) => key1,
Err(_) => {
crate::debug::error!("Invalid translate: fail to decode key1");
continue
},
None => continue,
};

let mut key2_material = G::Hasher2::reverse(&key_material);
let key2 = match K2::decode(&mut key2_material) {
Ok(key2) => key2,
Err(_) => {
crate::debug::error!("Invalid translate: fail to decode key2");
continue
},
};

match f(key1, key2, value) {
Some(new) => unhashed::put::<V>(&previous_key, &new),
None => unhashed::kill(&previous_key),
}
}
None => return,
Expand All @@ -450,7 +424,10 @@ impl<
#[allow(dead_code)]
mod test_iterators {
use codec::{Encode, Decode};
use crate::storage::{generator::StorageDoubleMap, IterableStorageDoubleMap, unhashed};
use crate::{
hash::StorageHasher,
storage::{generator::StorageDoubleMap, IterableStorageDoubleMap, unhashed},
};

pub trait Trait {
type Origin;
Expand All @@ -466,7 +443,7 @@ mod test_iterators {

crate::decl_storage! {
trait Store for Module<T: Trait> as Test {
DoubleMap: double_map hasher(blake2_128_concat) u16, hasher(blake2_128_concat) u32 => u64;
DoubleMap: double_map hasher(blake2_128_concat) u16, hasher(twox_64_concat) u32 => u64;
}
}

Expand All @@ -484,11 +461,6 @@ mod test_iterators {
prefix
}

fn key_in_prefix(mut prefix: Vec<u8>) -> Vec<u8> {
prefix.push(0);
prefix
}

#[test]
fn double_map_reversible_reversible_iteration() {
sp_io::TestExternalities::default().execute_with(|| {
Expand Down Expand Up @@ -534,22 +506,59 @@ mod test_iterators {

assert_eq!(
DoubleMap::iter_prefix(k1).collect::<Vec<_>>(),
vec![(0, 0), (2, 2), (1, 1), (3, 3)],
vec![(1, 1), (2, 2), (0, 0), (3, 3)],
);

assert_eq!(
DoubleMap::iter_prefix_values(k1).collect::<Vec<_>>(),
vec![0, 2, 1, 3],
vec![1, 2, 0, 3],
);

assert_eq!(
DoubleMap::drain_prefix(k1).collect::<Vec<_>>(),
vec![(0, 0), (2, 2), (1, 1), (3, 3)],
vec![(1, 1), (2, 2), (0, 0), (3, 3)],
);

assert_eq!(DoubleMap::iter_prefix(k1).collect::<Vec<_>>(), vec![]);
assert_eq!(unhashed::get(&key_before_prefix(prefix.clone())), Some(1u64));
assert_eq!(unhashed::get(&key_after_prefix(prefix.clone())), Some(1u64));

// Translate
let prefix = DoubleMap::prefix_hash();

unhashed::put(&key_before_prefix(prefix.clone()), &1u64);
unhashed::put(&key_after_prefix(prefix.clone()), &1u64);
for i in 0..4 {
DoubleMap::insert(i as u16, i as u32, i as u64);
}

// Wrong key1
unhashed::put(
&[prefix.clone(), vec![1, 2, 3]].concat(),
&3u64.encode()
);

// Wrong key2
unhashed::put(
&[prefix.clone(), crate::Blake2_128Concat::hash(&1u16.encode())].concat(),
&3u64.encode()
);

// Wrong value
unhashed::put(
&[
prefix.clone(),
crate::Blake2_128Concat::hash(&1u16.encode()),
crate::Twox64Concat::hash(&2u32.encode()),
].concat(),
&vec![1],
);

DoubleMap::translate(|_k1, _k2, v: u64| Some(v*2));
assert_eq!(
DoubleMap::iter().collect::<Vec<_>>(),
vec![(3, 3, 6), (0, 0, 0), (2, 2, 4), (1, 1, 2)],
);
})
}
}
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