1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
// This file is part of Substrate.

// Copyright (C) Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: Apache-2.0

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// 	http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! Some utilities for helping access storage with arbitrary key types.

use crate::{
	hash::ReversibleStorageHasher,
	storage::{storage_prefix, unhashed},
	StorageHasher, Twox128,
};
use alloc::{vec, vec::Vec};
use codec::{Decode, Encode};

use super::PrefixIterator;

/// Utility to iterate through raw items in storage.
pub struct StorageIterator<T> {
	prefix: Vec<u8>,
	previous_key: Vec<u8>,
	drain: bool,
	_phantom: ::core::marker::PhantomData<T>,
}

impl<T> StorageIterator<T> {
	/// Construct iterator to iterate over map items in `module` for the map called `item`.
	#[deprecated(note = "Will be removed after July 2023; Please use the storage_iter or \
		storage_iter_with_suffix functions instead")]
	pub fn new(module: &[u8], item: &[u8]) -> Self {
		#[allow(deprecated)]
		Self::with_suffix(module, item, &[][..])
	}

	/// Construct iterator to iterate over map items in `module` for the map called `item`.
	#[deprecated(note = "Will be removed after July 2023; Please use the storage_iter or \
		storage_iter_with_suffix functions instead")]
	pub fn with_suffix(module: &[u8], item: &[u8], suffix: &[u8]) -> Self {
		let mut prefix = Vec::new();
		let storage_prefix = storage_prefix(module, item);
		prefix.extend_from_slice(&storage_prefix);
		prefix.extend_from_slice(suffix);
		let previous_key = prefix.clone();
		Self { prefix, previous_key, drain: false, _phantom: Default::default() }
	}

	/// Mutate this iterator into a draining iterator; items iterated are removed from storage.
	pub fn drain(mut self) -> Self {
		self.drain = true;
		self
	}
}

impl<T: Decode + Sized> Iterator for StorageIterator<T> {
	type Item = (Vec<u8>, T);

	fn next(&mut self) -> Option<(Vec<u8>, T)> {
		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.clone();
					let maybe_value = frame_support::storage::unhashed::get::<T>(&next);
					match maybe_value {
						Some(value) => {
							if self.drain {
								frame_support::storage::unhashed::kill(&next);
							}
							Some((self.previous_key[self.prefix.len()..].to_vec(), value))
						},
						None => continue,
					}
				},
				None => None,
			}
		}
	}
}

/// Utility to iterate through raw items in storage.
pub struct StorageKeyIterator<K, T, H: ReversibleStorageHasher> {
	prefix: Vec<u8>,
	previous_key: Vec<u8>,
	drain: bool,
	_phantom: ::core::marker::PhantomData<(K, T, H)>,
}

impl<K, T, H: ReversibleStorageHasher> StorageKeyIterator<K, T, H> {
	/// Construct iterator to iterate over map items in `module` for the map called `item`.
	#[deprecated(note = "Will be removed after July 2023; Please use the storage_key_iter or \
		storage_key_iter_with_suffix functions instead")]
	pub fn new(module: &[u8], item: &[u8]) -> Self {
		#[allow(deprecated)]
		Self::with_suffix(module, item, &[][..])
	}

	/// Construct iterator to iterate over map items in `module` for the map called `item`.
	#[deprecated(note = "Will be removed after July 2023; Please use the storage_key_iter or \
		storage_key_iter_with_suffix functions instead")]
	pub fn with_suffix(module: &[u8], item: &[u8], suffix: &[u8]) -> Self {
		let mut prefix = Vec::new();
		let storage_prefix = storage_prefix(module, item);
		prefix.extend_from_slice(&storage_prefix);
		prefix.extend_from_slice(suffix);
		let previous_key = prefix.clone();
		Self { prefix, previous_key, drain: false, _phantom: Default::default() }
	}

	/// Mutate this iterator into a draining iterator; items iterated are removed from storage.
	pub fn drain(mut self) -> Self {
		self.drain = true;
		self
	}
}

impl<K: Decode + Sized, T: Decode + Sized, H: ReversibleStorageHasher> Iterator
	for StorageKeyIterator<K, T, H>
{
	type Item = (K, T);

	fn next(&mut self) -> Option<(K, T)> {
		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.clone();
					let mut key_material = H::reverse(&next[self.prefix.len()..]);
					match K::decode(&mut key_material) {
						Ok(key) => {
							let maybe_value = frame_support::storage::unhashed::get::<T>(&next);
							match maybe_value {
								Some(value) => {
									if self.drain {
										frame_support::storage::unhashed::kill(&next);
									}
									Some((key, value))
								},
								None => continue,
							}
						},
						Err(_) => continue,
					}
				},
				None => None,
			}
		}
	}
}

/// Construct iterator to iterate over map items in `module` for the map called `item`.
pub fn storage_iter<T: Decode + Sized>(module: &[u8], item: &[u8]) -> PrefixIterator<(Vec<u8>, T)> {
	storage_iter_with_suffix(module, item, &[][..])
}

/// Construct iterator to iterate over map items in `module` for the map called `item`.
pub fn storage_iter_with_suffix<T: Decode + Sized>(
	module: &[u8],
	item: &[u8],
	suffix: &[u8],
) -> PrefixIterator<(Vec<u8>, T)> {
	let mut prefix = Vec::new();
	let storage_prefix = storage_prefix(module, item);
	prefix.extend_from_slice(&storage_prefix);
	prefix.extend_from_slice(suffix);
	let previous_key = prefix.clone();
	let closure = |raw_key_without_prefix: &[u8], mut raw_value: &[u8]| {
		let value = T::decode(&mut raw_value)?;
		Ok((raw_key_without_prefix.to_vec(), value))
	};

	PrefixIterator { prefix, previous_key, drain: false, closure, phantom: Default::default() }
}

/// Construct iterator to iterate over map items in `module` for the map called `item`.
pub fn storage_key_iter<K: Decode + Sized, T: Decode + Sized, H: ReversibleStorageHasher>(
	module: &[u8],
	item: &[u8],
) -> PrefixIterator<(K, T)> {
	storage_key_iter_with_suffix::<K, T, H>(module, item, &[][..])
}

/// Construct iterator to iterate over map items in `module` for the map called `item`.
pub fn storage_key_iter_with_suffix<
	K: Decode + Sized,
	T: Decode + Sized,
	H: ReversibleStorageHasher,
>(
	module: &[u8],
	item: &[u8],
	suffix: &[u8],
) -> PrefixIterator<(K, T)> {
	let mut prefix = Vec::new();
	let storage_prefix = storage_prefix(module, item);

	prefix.extend_from_slice(&storage_prefix);
	prefix.extend_from_slice(suffix);
	let previous_key = prefix.clone();
	let closure = |raw_key_without_prefix: &[u8], mut raw_value: &[u8]| {
		let mut key_material = H::reverse(raw_key_without_prefix);
		let key = K::decode(&mut key_material)?;
		let value = T::decode(&mut raw_value)?;
		Ok((key, value))
	};
	PrefixIterator { prefix, previous_key, drain: false, closure, phantom: Default::default() }
}

/// Get a particular value in storage by the `module`, the map's `item` name and the key `hash`.
pub fn have_storage_value(module: &[u8], item: &[u8], hash: &[u8]) -> bool {
	get_storage_value::<()>(module, item, hash).is_some()
}

/// Get a particular value in storage by the `module`, the map's `item` name and the key `hash`.
pub fn get_storage_value<T: Decode + Sized>(module: &[u8], item: &[u8], hash: &[u8]) -> Option<T> {
	let mut key = vec![0u8; 32 + hash.len()];
	let storage_prefix = storage_prefix(module, item);
	key[0..32].copy_from_slice(&storage_prefix);
	key[32..].copy_from_slice(hash);
	frame_support::storage::unhashed::get::<T>(&key)
}

/// Take a particular value in storage by the `module`, the map's `item` name and the key `hash`.
pub fn take_storage_value<T: Decode + Sized>(module: &[u8], item: &[u8], hash: &[u8]) -> Option<T> {
	let mut key = vec![0u8; 32 + hash.len()];
	let storage_prefix = storage_prefix(module, item);
	key[0..32].copy_from_slice(&storage_prefix);
	key[32..].copy_from_slice(hash);
	frame_support::storage::unhashed::take::<T>(&key)
}

/// Put a particular value into storage by the `module`, the map's `item` name and the key `hash`.
pub fn put_storage_value<T: Encode>(module: &[u8], item: &[u8], hash: &[u8], value: T) {
	let mut key = vec![0u8; 32 + hash.len()];
	let storage_prefix = storage_prefix(module, item);
	key[0..32].copy_from_slice(&storage_prefix);
	key[32..].copy_from_slice(hash);
	frame_support::storage::unhashed::put(&key, &value);
}

/// Remove all items under a storage prefix by the `module`, the map's `item` name and the key
/// `hash`.
#[deprecated = "Use `clear_storage_prefix` instead"]
pub fn remove_storage_prefix(module: &[u8], item: &[u8], hash: &[u8]) {
	let mut key = vec![0u8; 32 + hash.len()];
	let storage_prefix = storage_prefix(module, item);
	key[0..32].copy_from_slice(&storage_prefix);
	key[32..].copy_from_slice(hash);
	let _ = frame_support::storage::unhashed::clear_prefix(&key, None, None);
}

/// Attempt to remove all values under a storage prefix by the `module`, the map's `item` name and
/// the key `hash`.
///
/// All values in the client overlay will be deleted, if `maybe_limit` is `Some` then up to
/// that number of values are deleted from the client backend by seeking and reading that number of
/// storage values plus one. If `maybe_limit` is `None` then all values in the client backend are
/// deleted. This is potentially unsafe since it's an unbounded operation.
///
/// ## Cursors
///
/// The `maybe_cursor` parameter should be `None` for the first call to initial removal.
/// If the resultant `maybe_cursor` is `Some`, then another call is required to complete the
/// removal operation. This value must be passed in as the subsequent call's `maybe_cursor`
/// parameter. If the resultant `maybe_cursor` is `None`, then the operation is complete and no
/// items remain in storage provided that no items were added between the first calls and the
/// final call.
pub fn clear_storage_prefix(
	module: &[u8],
	item: &[u8],
	hash: &[u8],
	maybe_limit: Option<u32>,
	maybe_cursor: Option<&[u8]>,
) -> sp_io::MultiRemovalResults {
	let mut key = vec![0u8; 32 + hash.len()];
	let storage_prefix = storage_prefix(module, item);
	key[0..32].copy_from_slice(&storage_prefix);
	key[32..].copy_from_slice(hash);
	frame_support::storage::unhashed::clear_prefix(&key, maybe_limit, maybe_cursor)
}

/// Take a particular item in storage by the `module`, the map's `item` name and the key `hash`.
pub fn take_storage_item<K: Encode + Sized, T: Decode + Sized, H: StorageHasher>(
	module: &[u8],
	item: &[u8],
	key: K,
) -> Option<T> {
	take_storage_value(module, item, key.using_encoded(H::hash).as_ref())
}

/// Move a storage from a pallet prefix to another pallet prefix.
///
/// Keys used in pallet storages always start with:
/// `concat(twox_128(pallet_name), twox_128(storage_name))`.
///
/// This function will remove all value for which the key start with
/// `concat(twox_128(old_pallet_name), twox_128(storage_name))` and insert them at the key with
/// the start replaced by `concat(twox_128(new_pallet_name), twox_128(storage_name))`.
///
/// # Example
///
/// If a pallet named "my_example" has 2 storages named "Foo" and "Bar" and the pallet is renamed
/// "my_new_example_name", a migration can be:
/// ```
/// # use frame_support::storage::migration::move_storage_from_pallet;
/// # sp_io::TestExternalities::new_empty().execute_with(|| {
/// move_storage_from_pallet(b"Foo", b"my_example", b"my_new_example_name");
/// move_storage_from_pallet(b"Bar", b"my_example", b"my_new_example_name");
/// # })
/// ```
pub fn move_storage_from_pallet(
	storage_name: &[u8],
	old_pallet_name: &[u8],
	new_pallet_name: &[u8],
) {
	let new_prefix = storage_prefix(new_pallet_name, storage_name);
	let old_prefix = storage_prefix(old_pallet_name, storage_name);

	move_prefix(&old_prefix, &new_prefix);

	if let Some(value) = unhashed::get_raw(&old_prefix) {
		unhashed::put_raw(&new_prefix, &value);
		unhashed::kill(&old_prefix);
	}
}

/// Move all storages from a pallet prefix to another pallet prefix.
///
/// Keys used in pallet storages always start with:
/// `concat(twox_128(pallet_name), twox_128(storage_name))`.
///
/// This function will remove all value for which the key start with `twox_128(old_pallet_name)`
/// and insert them at the key with the start replaced by `twox_128(new_pallet_name)`.
///
/// NOTE: The value at the key `twox_128(old_pallet_name)` is not moved.
///
/// # Example
///
/// If a pallet named "my_example" has some storages and the pallet is renamed
/// "my_new_example_name", a migration can be:
/// ```
/// # use frame_support::storage::migration::move_pallet;
/// # sp_io::TestExternalities::new_empty().execute_with(|| {
/// move_pallet(b"my_example", b"my_new_example_name");
/// # })
/// ```
pub fn move_pallet(old_pallet_name: &[u8], new_pallet_name: &[u8]) {
	move_prefix(&Twox128::hash(old_pallet_name), &Twox128::hash(new_pallet_name))
}

/// Move all `(key, value)` after some prefix to the another prefix
///
/// This function will remove all value for which the key start with `from_prefix`
/// and insert them at the key with the start replaced by `to_prefix`.
///
/// NOTE: The value at the key `from_prefix` is not moved.
pub fn move_prefix(from_prefix: &[u8], to_prefix: &[u8]) {
	if from_prefix == to_prefix {
		return
	}

	let iter = PrefixIterator::<_> {
		prefix: from_prefix.to_vec(),
		previous_key: from_prefix.to_vec(),
		drain: true,
		closure: |key, value| Ok((key.to_vec(), value.to_vec())),
		phantom: Default::default(),
	};

	for (key, value) in iter {
		let full_key = [to_prefix, &key].concat();
		unhashed::put_raw(&full_key, &value);
	}
}

#[cfg(test)]
mod tests {
	use super::{
		move_pallet, move_prefix, move_storage_from_pallet, storage_iter, storage_key_iter,
	};
	use crate::{
		hash::StorageHasher,
		pallet_prelude::{StorageMap, StorageValue, Twox128, Twox64Concat},
	};
	use sp_io::TestExternalities;

	struct OldPalletStorageValuePrefix;
	impl frame_support::traits::StorageInstance for OldPalletStorageValuePrefix {
		const STORAGE_PREFIX: &'static str = "foo_value";
		fn pallet_prefix() -> &'static str {
			"my_old_pallet"
		}
	}
	type OldStorageValue = StorageValue<OldPalletStorageValuePrefix, u32>;

	struct OldPalletStorageMapPrefix;
	impl frame_support::traits::StorageInstance for OldPalletStorageMapPrefix {
		const STORAGE_PREFIX: &'static str = "foo_map";
		fn pallet_prefix() -> &'static str {
			"my_old_pallet"
		}
	}
	type OldStorageMap = StorageMap<OldPalletStorageMapPrefix, Twox64Concat, u32, u32>;

	struct NewPalletStorageValuePrefix;
	impl frame_support::traits::StorageInstance for NewPalletStorageValuePrefix {
		const STORAGE_PREFIX: &'static str = "foo_value";
		fn pallet_prefix() -> &'static str {
			"my_new_pallet"
		}
	}
	type NewStorageValue = StorageValue<NewPalletStorageValuePrefix, u32>;

	struct NewPalletStorageMapPrefix;
	impl frame_support::traits::StorageInstance for NewPalletStorageMapPrefix {
		const STORAGE_PREFIX: &'static str = "foo_map";
		fn pallet_prefix() -> &'static str {
			"my_new_pallet"
		}
	}
	type NewStorageMap = StorageMap<NewPalletStorageMapPrefix, Twox64Concat, u32, u32>;

	#[test]
	fn test_move_prefix() {
		TestExternalities::new_empty().execute_with(|| {
			OldStorageValue::put(3);
			OldStorageMap::insert(1, 2);
			OldStorageMap::insert(3, 4);

			move_prefix(&Twox128::hash(b"my_old_pallet"), &Twox128::hash(b"my_new_pallet"));

			assert_eq!(OldStorageValue::get(), None);
			assert_eq!(OldStorageMap::iter().collect::<Vec<_>>(), vec![]);
			assert_eq!(NewStorageValue::get(), Some(3));
			assert_eq!(NewStorageMap::iter().collect::<Vec<_>>(), vec![(1, 2), (3, 4)]);
		})
	}

	#[test]
	fn test_move_storage() {
		TestExternalities::new_empty().execute_with(|| {
			OldStorageValue::put(3);
			OldStorageMap::insert(1, 2);
			OldStorageMap::insert(3, 4);

			move_storage_from_pallet(b"foo_map", b"my_old_pallet", b"my_new_pallet");

			assert_eq!(OldStorageValue::get(), Some(3));
			assert_eq!(OldStorageMap::iter().collect::<Vec<_>>(), vec![]);
			assert_eq!(NewStorageValue::get(), None);
			assert_eq!(NewStorageMap::iter().collect::<Vec<_>>(), vec![(1, 2), (3, 4)]);

			move_storage_from_pallet(b"foo_value", b"my_old_pallet", b"my_new_pallet");

			assert_eq!(OldStorageValue::get(), None);
			assert_eq!(OldStorageMap::iter().collect::<Vec<_>>(), vec![]);
			assert_eq!(NewStorageValue::get(), Some(3));
			assert_eq!(NewStorageMap::iter().collect::<Vec<_>>(), vec![(1, 2), (3, 4)]);
		})
	}

	#[test]
	fn test_move_pallet() {
		TestExternalities::new_empty().execute_with(|| {
			OldStorageValue::put(3);
			OldStorageMap::insert(1, 2);
			OldStorageMap::insert(3, 4);

			move_pallet(b"my_old_pallet", b"my_new_pallet");

			assert_eq!(OldStorageValue::get(), None);
			assert_eq!(OldStorageMap::iter().collect::<Vec<_>>(), vec![]);
			assert_eq!(NewStorageValue::get(), Some(3));
			assert_eq!(NewStorageMap::iter().collect::<Vec<_>>(), vec![(1, 2), (3, 4)]);
		})
	}

	#[test]
	fn test_storage_iter() {
		TestExternalities::new_empty().execute_with(|| {
			OldStorageValue::put(3);
			OldStorageMap::insert(1, 2);
			OldStorageMap::insert(3, 4);

			assert_eq!(
				storage_key_iter::<i32, i32, Twox64Concat>(b"my_old_pallet", b"foo_map")
					.collect::<Vec<_>>(),
				vec![(1, 2), (3, 4)],
			);

			assert_eq!(
				storage_iter(b"my_old_pallet", b"foo_map")
					.drain()
					.map(|t| t.1)
					.collect::<Vec<i32>>(),
				vec![2, 4],
			);
			assert_eq!(OldStorageMap::iter().collect::<Vec<_>>(), vec![]);

			// Empty because storage iterator skips over the entry under the first key
			assert_eq!(storage_iter::<i32>(b"my_old_pallet", b"foo_value").drain().next(), None);
			assert_eq!(OldStorageValue::get(), Some(3));
		});
	}
}