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
// This file is part of Substrate.

// Copyright (C) 2017-2022 Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.

use super::{client::ClientConfig, wasm_override::WasmOverride, wasm_substitutes::WasmSubstitutes};
use sc_client_api::{
	backend, call_executor::CallExecutor, execution_extensions::ExecutionExtensions, HeaderBackend,
};
use sc_executor::{RuntimeVersion, RuntimeVersionOf};
use sp_api::{ExecutionContext, ProofRecorder, StorageTransactionCache};
use sp_core::traits::{CodeExecutor, RuntimeCode, SpawnNamed};
use sp_runtime::{generic::BlockId, traits::Block as BlockT};
use sp_state_machine::{
	backend::AsTrieBackend, ExecutionStrategy, Ext, OverlayedChanges, StateMachine, StorageProof,
};
use std::{cell::RefCell, sync::Arc};

/// Call executor that executes methods locally, querying all required
/// data from local backend.
pub struct LocalCallExecutor<Block: BlockT, B, E> {
	backend: Arc<B>,
	executor: E,
	wasm_override: Arc<Option<WasmOverride>>,
	wasm_substitutes: WasmSubstitutes<Block, E, B>,
	spawn_handle: Box<dyn SpawnNamed>,
	execution_extensions: Arc<ExecutionExtensions<Block>>,
}

impl<Block: BlockT, B, E> LocalCallExecutor<Block, B, E>
where
	E: CodeExecutor + RuntimeVersionOf + Clone + 'static,
	B: backend::Backend<Block>,
{
	/// Creates new instance of local call executor.
	pub fn new(
		backend: Arc<B>,
		executor: E,
		spawn_handle: Box<dyn SpawnNamed>,
		client_config: ClientConfig<Block>,
		execution_extensions: ExecutionExtensions<Block>,
	) -> sp_blockchain::Result<Self> {
		let wasm_override = client_config
			.wasm_runtime_overrides
			.as_ref()
			.map(|p| WasmOverride::new(p.clone(), &executor))
			.transpose()?;

		let wasm_substitutes = WasmSubstitutes::new(
			client_config.wasm_runtime_substitutes,
			executor.clone(),
			backend.clone(),
		)?;

		Ok(LocalCallExecutor {
			backend,
			executor,
			wasm_override: Arc::new(wasm_override),
			spawn_handle,
			wasm_substitutes,
			execution_extensions: Arc::new(execution_extensions),
		})
	}

	/// Check if local runtime code overrides are enabled and one is available
	/// for the given `BlockId`. If yes, return it; otherwise return the same
	/// `RuntimeCode` instance that was passed.
	fn check_override<'a>(
		&'a self,
		onchain_code: RuntimeCode<'a>,
		hash: <Block as BlockT>::Hash,
	) -> sp_blockchain::Result<(RuntimeCode<'a>, RuntimeVersion)>
	where
		Block: BlockT,
		B: backend::Backend<Block>,
	{
		let on_chain_version = self.on_chain_runtime_version(hash)?;
		let code_and_version = if let Some(d) = self.wasm_override.as_ref().as_ref().and_then(|o| {
			o.get(
				&on_chain_version.spec_version,
				onchain_code.heap_pages,
				&on_chain_version.spec_name,
			)
		}) {
			log::debug!(target: "wasm_overrides", "using WASM override for block {}", hash);
			d
		} else if let Some(s) =
			self.wasm_substitutes
				.get(on_chain_version.spec_version, onchain_code.heap_pages, hash)
		{
			log::debug!(target: "wasm_substitutes", "Using WASM substitute for block {:?}", hash);
			s
		} else {
			log::debug!(
				target: "wasm_overrides",
				"Neither WASM override nor substitute available for block {hash}, using onchain code",
			);
			(onchain_code, on_chain_version)
		};

		Ok(code_and_version)
	}

	/// Returns the on chain runtime version.
	fn on_chain_runtime_version(&self, hash: Block::Hash) -> sp_blockchain::Result<RuntimeVersion> {
		let mut overlay = OverlayedChanges::default();

		let state = self.backend.state_at(hash)?;
		let mut cache = StorageTransactionCache::<Block, B::State>::default();
		let mut ext = Ext::new(&mut overlay, &mut cache, &state, None);
		let state_runtime_code = sp_state_machine::backend::BackendRuntimeCode::new(&state);
		let runtime_code =
			state_runtime_code.runtime_code().map_err(sp_blockchain::Error::RuntimeCode)?;
		self.executor
			.runtime_version(&mut ext, &runtime_code)
			.map_err(|e| sp_blockchain::Error::VersionInvalid(e.to_string()))
	}
}

impl<Block: BlockT, B, E> Clone for LocalCallExecutor<Block, B, E>
where
	E: Clone,
{
	fn clone(&self) -> Self {
		LocalCallExecutor {
			backend: self.backend.clone(),
			executor: self.executor.clone(),
			wasm_override: self.wasm_override.clone(),
			spawn_handle: self.spawn_handle.clone(),
			wasm_substitutes: self.wasm_substitutes.clone(),
			execution_extensions: self.execution_extensions.clone(),
		}
	}
}

impl<B, E, Block> CallExecutor<Block> for LocalCallExecutor<Block, B, E>
where
	B: backend::Backend<Block>,
	E: CodeExecutor + RuntimeVersionOf + Clone + 'static,
	Block: BlockT,
{
	type Error = E::Error;

	type Backend = B;

	fn execution_extensions(&self) -> &ExecutionExtensions<Block> {
		&self.execution_extensions
	}

	fn call(
		&self,
		at_hash: Block::Hash,
		method: &str,
		call_data: &[u8],
		strategy: ExecutionStrategy,
	) -> sp_blockchain::Result<Vec<u8>> {
		let mut changes = OverlayedChanges::default();
		let at_number =
			self.backend.blockchain().expect_block_number_from_id(&BlockId::Hash(at_hash))?;
		let state = self.backend.state_at(at_hash)?;

		let state_runtime_code = sp_state_machine::backend::BackendRuntimeCode::new(&state);
		let runtime_code =
			state_runtime_code.runtime_code().map_err(sp_blockchain::Error::RuntimeCode)?;

		let runtime_code = self.check_override(runtime_code, at_hash)?.0;

		let extensions = self.execution_extensions.extensions(
			at_hash,
			at_number,
			ExecutionContext::OffchainCall(None),
		);

		let mut sm = StateMachine::new(
			&state,
			&mut changes,
			&self.executor,
			method,
			call_data,
			extensions,
			&runtime_code,
			self.spawn_handle.clone(),
		)
		.set_parent_hash(at_hash);

		sm.execute_using_consensus_failure_handler(strategy.get_manager())
			.map_err(Into::into)
	}

	fn contextual_call(
		&self,
		at_hash: Block::Hash,
		method: &str,
		call_data: &[u8],
		changes: &RefCell<OverlayedChanges>,
		storage_transaction_cache: Option<&RefCell<StorageTransactionCache<Block, B::State>>>,
		recorder: &Option<ProofRecorder<Block>>,
		context: ExecutionContext,
	) -> Result<Vec<u8>, sp_blockchain::Error> {
		let mut storage_transaction_cache = storage_transaction_cache.map(|c| c.borrow_mut());

		let at_number =
			self.backend.blockchain().expect_block_number_from_id(&BlockId::Hash(at_hash))?;
		let state = self.backend.state_at(at_hash)?;

		let (execution_manager, extensions) =
			self.execution_extensions.manager_and_extensions(at_hash, at_number, context);

		let changes = &mut *changes.borrow_mut();

		// It is important to extract the runtime code here before we create the proof
		// recorder to not record it. We also need to fetch the runtime code from `state` to
		// make sure we use the caching layers.
		let state_runtime_code = sp_state_machine::backend::BackendRuntimeCode::new(&state);

		let runtime_code =
			state_runtime_code.runtime_code().map_err(sp_blockchain::Error::RuntimeCode)?;
		let runtime_code = self.check_override(runtime_code, at_hash)?.0;

		match recorder {
			Some(recorder) => {
				let trie_state = state.as_trie_backend();

				let backend = sp_state_machine::TrieBackendBuilder::wrap(&trie_state)
					.with_recorder(recorder.clone())
					.build();

				let mut state_machine = StateMachine::new(
					&backend,
					changes,
					&self.executor,
					method,
					call_data,
					extensions,
					&runtime_code,
					self.spawn_handle.clone(),
				)
				.with_storage_transaction_cache(storage_transaction_cache.as_deref_mut())
				.set_parent_hash(at_hash);
				state_machine.execute_using_consensus_failure_handler(execution_manager)
			},
			None => {
				let mut state_machine = StateMachine::new(
					&state,
					changes,
					&self.executor,
					method,
					call_data,
					extensions,
					&runtime_code,
					self.spawn_handle.clone(),
				)
				.with_storage_transaction_cache(storage_transaction_cache.as_deref_mut())
				.set_parent_hash(at_hash);
				state_machine.execute_using_consensus_failure_handler(execution_manager)
			},
		}
		.map_err(Into::into)
	}

	fn runtime_version(&self, at_hash: Block::Hash) -> sp_blockchain::Result<RuntimeVersion> {
		let state = self.backend.state_at(at_hash)?;
		let state_runtime_code = sp_state_machine::backend::BackendRuntimeCode::new(&state);

		let runtime_code =
			state_runtime_code.runtime_code().map_err(sp_blockchain::Error::RuntimeCode)?;
		self.check_override(runtime_code, at_hash).map(|(_, v)| v)
	}

	fn prove_execution(
		&self,
		at_hash: Block::Hash,
		method: &str,
		call_data: &[u8],
	) -> sp_blockchain::Result<(Vec<u8>, StorageProof)> {
		let at_number =
			self.backend.blockchain().expect_block_number_from_id(&BlockId::Hash(at_hash))?;
		let state = self.backend.state_at(at_hash)?;

		let trie_backend = state.as_trie_backend();

		let state_runtime_code = sp_state_machine::backend::BackendRuntimeCode::new(trie_backend);
		let runtime_code =
			state_runtime_code.runtime_code().map_err(sp_blockchain::Error::RuntimeCode)?;
		let runtime_code = self.check_override(runtime_code, at_hash)?.0;

		sp_state_machine::prove_execution_on_trie_backend(
			trie_backend,
			&mut Default::default(),
			&self.executor,
			self.spawn_handle.clone(),
			method,
			call_data,
			&runtime_code,
			self.execution_extensions.extensions(
				at_hash,
				at_number,
				ExecutionContext::OffchainCall(None),
			),
		)
		.map_err(Into::into)
	}
}

impl<B, E, Block> RuntimeVersionOf for LocalCallExecutor<Block, B, E>
where
	E: RuntimeVersionOf,
	Block: BlockT,
{
	fn runtime_version(
		&self,
		ext: &mut dyn sp_externalities::Externalities,
		runtime_code: &sp_core::traits::RuntimeCode,
	) -> Result<sp_version::RuntimeVersion, sc_executor::error::Error> {
		RuntimeVersionOf::runtime_version(&self.executor, ext, runtime_code)
	}
}

impl<Block, B, E> sp_version::GetRuntimeVersionAt<Block> for LocalCallExecutor<Block, B, E>
where
	B: backend::Backend<Block>,
	E: CodeExecutor + RuntimeVersionOf + Clone + 'static,
	Block: BlockT,
{
	fn runtime_version(&self, at: Block::Hash) -> Result<sp_version::RuntimeVersion, String> {
		CallExecutor::runtime_version(self, at).map_err(|e| e.to_string())
	}
}

impl<Block, B, E> sp_version::GetNativeVersion for LocalCallExecutor<Block, B, E>
where
	B: backend::Backend<Block>,
	E: CodeExecutor + sp_version::GetNativeVersion + Clone + 'static,
	Block: BlockT,
{
	fn native_version(&self) -> &sp_version::NativeVersion {
		self.executor.native_version()
	}
}

#[cfg(test)]
mod tests {
	use super::*;
	use backend::Backend;
	use sc_client_api::in_mem;
	use sc_executor::{NativeElseWasmExecutor, WasmExecutionMethod};
	use sp_core::{
		testing::TaskExecutor,
		traits::{FetchRuntimeCode, WrappedRuntimeCode},
	};
	use std::collections::HashMap;
	use substrate_test_runtime_client::{runtime, GenesisInit, LocalExecutorDispatch};

	#[test]
	fn should_get_override_if_exists() {
		let executor = NativeElseWasmExecutor::<LocalExecutorDispatch>::new(
			WasmExecutionMethod::Interpreted,
			Some(128),
			1,
			2,
		);

		let overrides = crate::client::wasm_override::dummy_overrides();
		let onchain_code = WrappedRuntimeCode(substrate_test_runtime::wasm_binary_unwrap().into());
		let onchain_code = RuntimeCode {
			code_fetcher: &onchain_code,
			heap_pages: Some(128),
			hash: vec![0, 0, 0, 0],
		};

		let backend = Arc::new(in_mem::Backend::<runtime::Block>::new());

		// wasm_runtime_overrides is `None` here because we construct the
		// LocalCallExecutor directly later on
		let client_config = ClientConfig::default();

		let genesis_block_builder = crate::GenesisBlockBuilder::new(
			&substrate_test_runtime_client::GenesisParameters::default().genesis_storage(),
			!client_config.no_genesis,
			backend.clone(),
			executor.clone(),
		)
		.expect("Creates genesis block builder");

		// client is used for the convenience of creating and inserting the genesis block.
		let _client =
			crate::client::new_with_backend::<_, _, runtime::Block, _, runtime::RuntimeApi>(
				backend.clone(),
				executor.clone(),
				genesis_block_builder,
				None,
				Box::new(TaskExecutor::new()),
				None,
				None,
				client_config,
			)
			.expect("Creates a client");

		let call_executor = LocalCallExecutor {
			backend: backend.clone(),
			executor: executor.clone(),
			wasm_override: Arc::new(Some(overrides)),
			spawn_handle: Box::new(TaskExecutor::new()),
			wasm_substitutes: WasmSubstitutes::new(
				Default::default(),
				executor.clone(),
				backend.clone(),
			)
			.unwrap(),
			execution_extensions: Arc::new(ExecutionExtensions::new(
				Default::default(),
				None,
				None,
			)),
		};

		let check = call_executor
			.check_override(onchain_code, backend.blockchain().info().genesis_hash)
			.expect("RuntimeCode override")
			.0;

		assert_eq!(Some(vec![2, 2, 2, 2, 2, 2, 2, 2]), check.fetch_runtime_code().map(Into::into));
	}

	#[test]
	fn returns_runtime_version_from_substitute() {
		const SUBSTITUTE_SPEC_NAME: &str = "substitute-spec-name-cool";

		let executor = NativeElseWasmExecutor::<LocalExecutorDispatch>::new(
			WasmExecutionMethod::Interpreted,
			Some(128),
			1,
			2,
		);

		let backend = Arc::new(in_mem::Backend::<runtime::Block>::new());

		// Let's only override the `spec_name` for our testing purposes.
		let substitute = sp_version::embed::embed_runtime_version(
			&substrate_test_runtime::WASM_BINARY_BLOATY.unwrap(),
			sp_version::RuntimeVersion {
				spec_name: SUBSTITUTE_SPEC_NAME.into(),
				..substrate_test_runtime::VERSION
			},
		)
		.unwrap();

		let client_config = crate::client::ClientConfig {
			wasm_runtime_substitutes: vec![(0, substitute)].into_iter().collect::<HashMap<_, _>>(),
			..Default::default()
		};

		let genesis_block_builder = crate::GenesisBlockBuilder::new(
			&substrate_test_runtime_client::GenesisParameters::default().genesis_storage(),
			!client_config.no_genesis,
			backend.clone(),
			executor.clone(),
		)
		.expect("Creates genesis block builder");

		// client is used for the convenience of creating and inserting the genesis block.
		let client =
			crate::client::new_with_backend::<_, _, runtime::Block, _, runtime::RuntimeApi>(
				backend.clone(),
				executor.clone(),
				genesis_block_builder,
				None,
				Box::new(TaskExecutor::new()),
				None,
				None,
				client_config,
			)
			.expect("Creates a client");

		let version = client.runtime_version_at(&BlockId::Number(0)).unwrap();

		assert_eq!(SUBSTITUTE_SPEC_NAME, &*version.spec_name);
	}
}