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
// This file is part of Substrate.

// Copyright (C) 2017-2020 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.

//! State machine backends. These manage the code and storage of contracts.

use hash_db::Hasher;
use codec::{Decode, Encode};
use sp_core::{
	storage::{ChildInfo, well_known_keys, TrackedStorageKey}
};
use crate::{
	trie_backend::TrieBackend,
	trie_backend_essence::TrieBackendStorage,
	UsageInfo, StorageKey, StorageValue, StorageCollection, ChildStorageCollection,
};
use sp_std::vec::Vec;
#[cfg(feature = "std")]
use sp_core::traits::RuntimeCode;

/// A state backend is used to read state data and can have changes committed
/// to it.
///
/// The clone operation (if implemented) should be cheap.
pub trait Backend<H: Hasher>: sp_std::fmt::Debug {
	/// An error type when fetching data is not possible.
	type Error: super::Error;

	/// Storage changes to be applied if committing
	type Transaction: Consolidate + Default + Send;

	/// Type of trie backend storage.
	type TrieBackendStorage: TrieBackendStorage<H>;

	/// Get keyed storage or None if there is nothing associated.
	fn storage(&self, key: &[u8]) -> Result<Option<StorageValue>, Self::Error>;

	/// Get keyed storage value hash or None if there is nothing associated.
	fn storage_hash(&self, key: &[u8]) -> Result<Option<H::Out>, Self::Error> {
		self.storage(key).map(|v| v.map(|v| H::hash(&v)))
	}

	/// Get keyed child storage or None if there is nothing associated.
	fn child_storage(
		&self,
		child_info: &ChildInfo,
		key: &[u8],
	) -> Result<Option<StorageValue>, Self::Error>;

	/// Get child keyed storage value hash or None if there is nothing associated.
	fn child_storage_hash(
		&self,
		child_info: &ChildInfo,
		key: &[u8],
	) -> Result<Option<H::Out>, Self::Error> {
		self.child_storage(child_info, key).map(|v| v.map(|v| H::hash(&v)))
	}

	/// true if a key exists in storage.
	fn exists_storage(&self, key: &[u8]) -> Result<bool, Self::Error> {
		Ok(self.storage(key)?.is_some())
	}

	/// true if a key exists in child storage.
	fn exists_child_storage(
		&self,
		child_info: &ChildInfo,
		key: &[u8],
	) -> Result<bool, Self::Error> {
		Ok(self.child_storage(child_info, key)?.is_some())
	}

	/// Return the next key in storage in lexicographic order or `None` if there is no value.
	fn next_storage_key(&self, key: &[u8]) -> Result<Option<StorageKey>, Self::Error>;

	/// Return the next key in child storage in lexicographic order or `None` if there is no value.
	fn next_child_storage_key(
		&self,
		child_info: &ChildInfo,
		key: &[u8]
	) -> Result<Option<StorageKey>, Self::Error>;

	/// Retrieve all entries keys of child storage and call `f` for each of those keys.
	fn for_keys_in_child_storage<F: FnMut(&[u8])>(
		&self,
		child_info: &ChildInfo,
		f: F,
	);

	/// Retrieve all entries keys which start with the given prefix and
	/// call `f` for each of those keys.
	fn for_keys_with_prefix<F: FnMut(&[u8])>(&self, prefix: &[u8], mut f: F) {
		self.for_key_values_with_prefix(prefix, |k, _v| f(k))
	}

	/// Retrieve all entries keys and values of which start with the given prefix and
	/// call `f` for each of those keys.
	fn for_key_values_with_prefix<F: FnMut(&[u8], &[u8])>(&self, prefix: &[u8], f: F);


	/// Retrieve all child entries keys which start with the given prefix and
	/// call `f` for each of those keys.
	fn for_child_keys_with_prefix<F: FnMut(&[u8])>(
		&self,
		child_info: &ChildInfo,
		prefix: &[u8],
		f: F,
	);

	/// Calculate the storage root, with given delta over what is already stored in
	/// the backend, and produce a "transaction" that can be used to commit.
	/// Does not include child storage updates.
	fn storage_root<'a>(
		&self,
		delta: impl Iterator<Item=(&'a [u8], Option<&'a [u8]>)>,
	) -> (H::Out, Self::Transaction) where H::Out: Ord;

	/// Calculate the child storage root, with given delta over what is already stored in
	/// the backend, and produce a "transaction" that can be used to commit. The second argument
	/// is true if child storage root equals default storage root.
	fn child_storage_root<'a>(
		&self,
		child_info: &ChildInfo,
		delta: impl Iterator<Item=(&'a [u8], Option<&'a [u8]>)>,
	) -> (H::Out, bool, Self::Transaction) where H::Out: Ord;

	/// Get all key/value pairs into a Vec.
	fn pairs(&self) -> Vec<(StorageKey, StorageValue)>;

	/// Get all keys with given prefix
	fn keys(&self, prefix: &[u8]) -> Vec<StorageKey> {
		let mut all = Vec::new();
		self.for_keys_with_prefix(prefix, |k| all.push(k.to_vec()));
		all
	}

	/// Get all keys of child storage with given prefix
	fn child_keys(
		&self,
		child_info: &ChildInfo,
		prefix: &[u8],
	) -> Vec<StorageKey> {
		let mut all = Vec::new();
		self.for_child_keys_with_prefix(child_info, prefix, |k| all.push(k.to_vec()));
		all
	}

	/// Try convert into trie backend.
	fn as_trie_backend(&mut self) -> Option<&TrieBackend<Self::TrieBackendStorage, H>> {
		None
	}

	/// Calculate the storage root, with given delta over what is already stored
	/// in the backend, and produce a "transaction" that can be used to commit.
	/// Does include child storage updates.
	fn full_storage_root<'a>(
		&self,
		delta: impl Iterator<Item=(&'a [u8], Option<&'a [u8]>)>,
		child_deltas: impl Iterator<Item = (
			&'a ChildInfo,
			impl Iterator<Item=(&'a [u8], Option<&'a [u8]>)>,
		)>,
	) -> (H::Out, Self::Transaction) where H::Out: Ord + Encode {
		let mut txs: Self::Transaction = Default::default();
		let mut child_roots: Vec<_> = Default::default();
		// child first
		for (child_info, child_delta) in child_deltas {
			let (child_root, empty, child_txs) =
				self.child_storage_root(&child_info, child_delta);
			let prefixed_storage_key = child_info.prefixed_storage_key();
			txs.consolidate(child_txs);
			if empty {
				child_roots.push((prefixed_storage_key.into_inner(), None));
			} else {
				child_roots.push((prefixed_storage_key.into_inner(), Some(child_root.encode())));
			}
		}
		let (root, parent_txs) = self.storage_root(delta
			.map(|(k, v)| (&k[..], v.as_ref().map(|v| &v[..])))
			.chain(
				child_roots
					.iter()
					.map(|(k, v)| (&k[..], v.as_ref().map(|v| &v[..])))
			)
		);
		txs.consolidate(parent_txs);
		(root, txs)
	}

	/// Register stats from overlay of state machine.
	///
	/// By default nothing is registered.
	fn register_overlay_stats(&mut self, _stats: &crate::stats::StateMachineStats);

	/// Query backend usage statistics (i/o, memory)
	///
	/// Not all implementations are expected to be able to do this. In the
	/// case when they don't, empty statistics is returned.
	fn usage_info(&self) -> UsageInfo;

	/// Wipe the state database.
	fn wipe(&self) -> Result<(), Self::Error> {
		unimplemented!()
	}

	/// Commit given transaction to storage.
	fn commit(
		&self,
		_: H::Out,
		_: Self::Transaction,
		_: StorageCollection,
		_: ChildStorageCollection,
	) -> Result<(), Self::Error> {
		unimplemented!()
	}

	/// Get the read/write count of the db
	fn read_write_count(&self) -> (u32, u32, u32, u32) {
		unimplemented!()
	}

	/// Get the read/write count of the db
	fn reset_read_write_count(&self) {
		unimplemented!()
	}

	/// Get the whitelist for tracking db reads/writes
	fn get_whitelist(&self) -> Vec<TrackedStorageKey> {
		Default::default()
	}

	/// Update the whitelist for tracking db reads/writes
	fn set_whitelist(&self, _: Vec<TrackedStorageKey>) {}
}

impl<'a, T: Backend<H>, H: Hasher> Backend<H> for &'a T {
	type Error = T::Error;
	type Transaction = T::Transaction;
	type TrieBackendStorage = T::TrieBackendStorage;

	fn storage(&self, key: &[u8]) -> Result<Option<StorageKey>, Self::Error> {
		(*self).storage(key)
	}

	fn child_storage(
		&self,
		child_info: &ChildInfo,
		key: &[u8],
	) -> Result<Option<StorageKey>, Self::Error> {
		(*self).child_storage(child_info, key)
	}

	fn for_keys_in_child_storage<F: FnMut(&[u8])>(
		&self,
		child_info: &ChildInfo,
		f: F,
	) {
		(*self).for_keys_in_child_storage(child_info, f)
	}

	fn next_storage_key(&self, key: &[u8]) -> Result<Option<StorageKey>, Self::Error> {
		(*self).next_storage_key(key)
	}

	fn next_child_storage_key(
		&self,
		child_info: &ChildInfo,
		key: &[u8],
	) -> Result<Option<StorageKey>, Self::Error> {
		(*self).next_child_storage_key(child_info, key)
	}

	fn for_keys_with_prefix<F: FnMut(&[u8])>(&self, prefix: &[u8], f: F) {
		(*self).for_keys_with_prefix(prefix, f)
	}

	fn for_child_keys_with_prefix<F: FnMut(&[u8])>(
		&self,
		child_info: &ChildInfo,
		prefix: &[u8],
		f: F,
	) {
		(*self).for_child_keys_with_prefix(child_info, prefix, f)
	}

	fn storage_root<'b>(
		&self,
		delta: impl Iterator<Item=(&'b [u8], Option<&'b [u8]>)>,
	) -> (H::Out, Self::Transaction) where H::Out: Ord {
		(*self).storage_root(delta)
	}

	fn child_storage_root<'b>(
		&self,
		child_info: &ChildInfo,
		delta: impl Iterator<Item=(&'b [u8], Option<&'b [u8]>)>,
	) -> (H::Out, bool, Self::Transaction) where H::Out: Ord {
		(*self).child_storage_root(child_info, delta)
	}

	fn pairs(&self) -> Vec<(StorageKey, StorageValue)> {
		(*self).pairs()
	}

	fn for_key_values_with_prefix<F: FnMut(&[u8], &[u8])>(&self, prefix: &[u8], f: F) {
		(*self).for_key_values_with_prefix(prefix, f);
	}

	fn register_overlay_stats(&mut self, _stats: &crate::stats::StateMachineStats) {	}

	fn usage_info(&self) -> UsageInfo {
		(*self).usage_info()
	}
}

/// Trait that allows consolidate two transactions together.
pub trait Consolidate {
	/// Consolidate two transactions into one.
	fn consolidate(&mut self, other: Self);
}

impl Consolidate for () {
	fn consolidate(&mut self, _: Self) {
		()
	}
}

impl Consolidate for Vec<(
		Option<ChildInfo>,
		StorageCollection,
	)> {
	fn consolidate(&mut self, mut other: Self) {
		self.append(&mut other);
	}
}

impl<H: Hasher, KF: sp_trie::KeyFunction<H>> Consolidate for sp_trie::GenericMemoryDB<H, KF> {
	fn consolidate(&mut self, other: Self) {
		sp_trie::GenericMemoryDB::consolidate(self, other)
	}
}

/// Insert input pairs into memory db.
#[cfg(test)]
pub(crate) fn insert_into_memory_db<H, I>(mdb: &mut sp_trie::MemoryDB<H>, input: I) -> Option<H::Out>
	where
		H: Hasher,
		I: IntoIterator<Item=(StorageKey, StorageValue)>,
{
	use sp_trie::{TrieMut, trie_types::TrieDBMut};

	let mut root = <H as Hasher>::Out::default();
	{
		let mut trie = TrieDBMut::<H>::new(mdb, &mut root);
		for (key, value) in input {
			if let Err(e) = trie.insert(&key, &value) {
				log::warn!(target: "trie", "Failed to write to trie: {}", e);
				return None;
			}
		}
	}

	Some(root)
}

/// Wrapper to create a [`RuntimeCode`] from a type that implements [`Backend`].
#[cfg(feature = "std")]
pub struct BackendRuntimeCode<'a, B, H> {
	backend: &'a B,
	_marker: std::marker::PhantomData<H>,
}

#[cfg(feature = "std")]
impl<'a, B: Backend<H>, H: Hasher> sp_core::traits::FetchRuntimeCode for
	BackendRuntimeCode<'a, B, H>
{
	fn fetch_runtime_code<'b>(&'b self) -> Option<std::borrow::Cow<'b, [u8]>> {
		self.backend.storage(well_known_keys::CODE).ok().flatten().map(Into::into)
	}
}

#[cfg(feature = "std")]
impl<'a, B: Backend<H>, H: Hasher> BackendRuntimeCode<'a, B, H> where H::Out: Encode {
	/// Create a new instance.
	pub fn new(backend: &'a B) -> Self {
		Self {
			backend,
			_marker: std::marker::PhantomData,
		}
	}

	/// Return the [`RuntimeCode`] build from the wrapped `backend`.
	pub fn runtime_code(&self) -> Result<RuntimeCode, &'static str> {
		let hash = self.backend.storage_hash(well_known_keys::CODE)
			.ok()
			.flatten()
			.ok_or("`:code` hash not found")?
			.encode();
		let heap_pages = self.backend.storage(well_known_keys::HEAP_PAGES)
			.ok()
			.flatten()
			.and_then(|d| Decode::decode(&mut &d[..]).ok());

		Ok(RuntimeCode { code_fetcher: self, hash, heap_pages })
	}
}