      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
    518
    519
    520
    521
    522
    523
    524
    525
    526
    527
    528
    529
    530
    531
    532
    533
    534
    535
    536
    537
    538
    539
    540
    541
    542
    543
    544
    545
    546
    547
    548
    549
    550
    551
    552
    553
    554
    555
    556
    557
    558
    559
    560
    561
    562
    563
    564
    565
    566
    567
    568
    569
    570
    571
    572
    573
    574
    575
    576
    577
    578
    579
    580
    581
    582
    583
    584
    585
    586
    587
    588
    589
    590
    591
    592
    593
    594
    595
    596
    597
    598
    599
    600
    601
    602
    603
    604
    605
    606
    607
    608
    609
    610
    611
    612
    613
    614
    615
    616
    617
    618
    619
    620
    621
    622
    623
    624
    625
    626
    627
    628
    629
    630
    631
    632
    633
    634
    635
    636
    637
    638
    639
    640
    641
    642
    643
    644
    645
    646
    647
    648
    649
    650
    651
    652
    653
    654
    655
    656
    657
    658
    659
    660
    661
    662
    663
    664
    665
    666
    667
    668
    669
    670
    671
    672
    673
    674
    675
    676
    677
    678
    679
    680
    681
    682
    683
    684
    685
    686
    687
    688
    689
    690
    691
    692
    693
    694
    695
    696
    697
    698
    699
    700
    701
    702
    703
    704
    705
    706
    707
    708
    709
    710
    711
    712
    713
    714
    715
    716
    717
    718
    719
    720
    721
    722
    723
    724
    725
    726
    727
    728
    729
    730
    731

    // Copyright 2015-2017 Parity Technologies (UK) Ltd.
    // This file is part of Parity.

    // Parity 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.

    // Parity 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 Parity.  If not, see <http://www.gnu.org/licenses/>.

    //! Blockchain block.

    use std::cmp;
    use std::sync::Arc;
    use std::collections::HashSet;

    use rlp::{UntrustedRlp, RlpStream, Encodable, Decodable, Decoder, DecoderError, View, Stream};
    use util::{Bytes, Address, Uint, FixedHash, Hashable, U256, H256, ordered_trie_root, SHA3_NULL_RLP};
    use util::error::{Mismatch, OutOfBounds};

    use basic_types::{LogBloom, Seal};
    use env_info::{EnvInfo, LastHashes};
    use engines::Engine;
    use error::{Error, BlockError, TransactionError};
    use factory::Factories;
    use header::Header;
    use receipt::Receipt;
    use state::State;
    use state_db::StateDB;
    use trace::FlatTrace;
    use transaction::{UnverifiedTransaction, SignedTransaction};
    use verification::PreverifiedBlock;
    use views::BlockView;

    /// A block, encoded as it is on the block chain.
    #[derive(Default, Debug, Clone, PartialEq)]
    pub struct Block {
    	/// The header of this block.
    	pub header: Header,
    	/// The transactions in this block.
    	pub transactions: Vec<UnverifiedTransaction>,
    	/// The uncles of this block.
    	pub uncles: Vec<Header>,
    }

    impl Block {
    	/// Returns true if the given bytes form a valid encoding of a block in RLP.
    	pub fn is_good(b: &[u8]) -> bool {
    		UntrustedRlp::new(b).as_val::<Block>().is_ok()
    	}

    	/// Get the RLP-encoding of the block with or without the seal.
    	pub fn rlp_bytes(&self, seal: Seal) -> Bytes {
    		let mut block_rlp = RlpStream::new_list(3);
    		self.header.stream_rlp(&mut block_rlp, seal);
    		block_rlp.append(&self.transactions);
    		block_rlp.append(&self.uncles);
    		block_rlp.out()
    	}
    }

    impl Decodable for Block {
    	fn decode<D>(decoder: &D) -> Result<Self, DecoderError> where D: Decoder {
    		if decoder.as_raw().len() != decoder.as_rlp().payload_info()?.total() {
    			return Err(DecoderError::RlpIsTooBig);
    		}
    		let d = decoder.as_rlp();
    		if d.item_count() != 3 {
    			return Err(DecoderError::RlpIncorrectListLen);
    		}
    		Ok(Block {
    			header: d.val_at(0)?,
    			transactions: d.val_at(1)?,
    			uncles: d.val_at(2)?,
    		})
    	}
    }

    /// An internal type for a block's common elements.
    #[derive(Clone)]
    pub struct ExecutedBlock {
    	header: Header,
    	transactions: Vec<SignedTransaction>,
    	uncles: Vec<Header>,
    	receipts: Vec<Receipt>,
    	transactions_set: HashSet<H256>,
    	state: State,
    	traces: Option<Vec<Vec<FlatTrace>>>,
    }

    /// A set of references to `ExecutedBlock` fields that are publicly accessible.
    pub struct BlockRefMut<'a> {
    	/// Block header.
    	pub header: &'a mut Header,
    	/// Block transactions.
    	pub transactions: &'a [SignedTransaction],
    	/// Block uncles.
    	pub uncles: &'a [Header],
    	/// Transaction receipts.
    	pub receipts: &'a [Receipt],
    	/// State.
    	pub state: &'a mut State,
    	/// Traces.
    	pub traces: &'a Option<Vec<Vec<FlatTrace>>>,
    }

    /// A set of immutable references to `ExecutedBlock` fields that are publicly accessible.
    pub struct BlockRef<'a> {
    	/// Block header.
    	pub header: &'a Header,
    	/// Block transactions.
    	pub transactions: &'a [SignedTransaction],
    	/// Block uncles.
    	pub uncles: &'a [Header],
    	/// Transaction receipts.
    	pub receipts: &'a [Receipt],
    	/// State.
    	pub state: &'a State,
    	/// Traces.
    	pub traces: &'a Option<Vec<Vec<FlatTrace>>>,
    }

    impl ExecutedBlock {
    	/// Create a new block from the given `state`.
    	fn new(state: State, tracing: bool) -> ExecutedBlock {
    		ExecutedBlock {
    			header: Default::default(),
    			transactions: Default::default(),
    			uncles: Default::default(),
    			receipts: Default::default(),
    			transactions_set: Default::default(),
    			state: state,
    			traces: if tracing {Some(Vec::new())} else {None},
    		}
    	}

    	/// Get a structure containing individual references to all public fields.
    	pub fn fields_mut(&mut self) -> BlockRefMut {
    		BlockRefMut {
    			header: &mut self.header,
    			transactions: &self.transactions,
    			uncles: &self.uncles,
    			state: &mut self.state,
    			receipts: &self.receipts,
    			traces: &self.traces,
    		}
    	}

    	/// Get a structure containing individual references to all public fields.
    	pub fn fields(&self) -> BlockRef {
    		BlockRef {
    			header: &self.header,
    			transactions: &self.transactions,
    			uncles: &self.uncles,
    			state: &self.state,
    			receipts: &self.receipts,
    			traces: &self.traces,
    		}
    	}
    }

    /// Trait for a object that is a `ExecutedBlock`.
    pub trait IsBlock {
    	/// Get the `ExecutedBlock` associated with this object.
    	fn block(&self) -> &ExecutedBlock;

    	/// Get the base `Block` object associated with this.
    	fn to_base(&self) -> Block {
    		Block {
    			header: self.header().clone(),
    			transactions: self.transactions().iter().cloned().map(Into::into).collect(),
    			uncles: self.uncles().to_vec(),
    		}
    	}

    	/// Get the header associated with this object's block.
    	fn header(&self) -> &Header { &self.block().header }

    	/// Get the final state associated with this object's block.
    	fn state(&self) -> &State { &self.block().state }

    	/// Get all information on transactions in this block.
    	fn transactions(&self) -> &[SignedTransaction] { &self.block().transactions }

    	/// Get all information on receipts in this block.
    	fn receipts(&self) -> &[Receipt] { &self.block().receipts }

    	/// Get all information concerning transaction tracing in this block.
    	fn traces(&self) -> &Option<Vec<Vec<FlatTrace>>> { &self.block().traces }

    	/// Get all uncles in this block.
    	fn uncles(&self) -> &[Header] { &self.block().uncles }
    }

    /// Trait for a object that has a state database.
    pub trait Drain {
    	/// Drop this object and return the underlieing database.
    	fn drain(self) -> StateDB;
    }

    impl IsBlock for ExecutedBlock {
    	fn block(&self) -> &ExecutedBlock { self }
    }

    /// Block that is ready for transactions to be added.
    ///
    /// It's a bit like a Vec<Transaction>, except that whenever a transaction is pushed, we execute it and
    /// maintain the system `state()`. We also archive execution receipts in preparation for later block creation.
    pub struct OpenBlock<'x> {
    	block: ExecutedBlock,
    	engine: &'x Engine,
    	last_hashes: Arc<LastHashes>,
    }

    /// Just like `OpenBlock`, except that we've applied `Engine::on_close_block`, finished up the non-seal header fields,
    /// and collected the uncles.
    ///
    /// There is no function available to push a transaction.
    #[derive(Clone)]
    pub struct ClosedBlock {
    	block: ExecutedBlock,
    	uncle_bytes: Bytes,
    	last_hashes: Arc<LastHashes>,
    	unclosed_state: State,
    }

    /// Just like `ClosedBlock` except that we can't reopen it and it's faster.
    ///
    /// We actually store the post-`Engine::on_close_block` state, unlike in `ClosedBlock` where it's the pre.
    #[derive(Clone)]
    pub struct LockedBlock {
    	block: ExecutedBlock,
    	uncle_bytes: Bytes,
    }

    /// A block that has a valid seal.
    ///
    /// The block's header has valid seal arguments. The block cannot be reversed into a `ClosedBlock` or `OpenBlock`.
    pub struct SealedBlock {
    	block: ExecutedBlock,
    	uncle_bytes: Bytes,
    }

    impl<'x> OpenBlock<'x> {
    	#[cfg_attr(feature="dev", allow(too_many_arguments))]
    	/// Create a new `OpenBlock` ready for transaction pushing.
    	pub fn new(
    		engine: &'x Engine,
    		factories: Factories,
    		tracing: bool,
    		db: StateDB,
    		parent: &Header,
    		last_hashes: Arc<LastHashes>,
    		author: Address,
    		gas_range_target: (U256, U256),
    		extra_data: Bytes,
    	) -> Result<Self, Error> {
    		let state = State::from_existing(db, parent.state_root().clone(), engine.account_start_nonce(), factories)?;
    		let mut r = OpenBlock {
    			block: ExecutedBlock::new(state, tracing),
    			engine: engine,
    			last_hashes: last_hashes,
    		};

    		r.block.header.set_parent_hash(parent.hash());
    		r.block.header.set_number(parent.number() + 1);
    		r.block.header.set_author(author);
    		r.block.header.set_timestamp_now(parent.timestamp());
    		r.block.header.set_extra_data(extra_data);
    		r.block.header.note_dirty();

    		let gas_floor_target = cmp::max(gas_range_target.0, engine.params().min_gas_limit);
    		let gas_ceil_target = cmp::max(gas_range_target.1, gas_floor_target);
    		engine.populate_from_parent(&mut r.block.header, parent, gas_floor_target, gas_ceil_target);
    		engine.on_new_block(&mut r.block);
    		Ok(r)
    	}

    	/// Alter the author for the block.
    	pub fn set_author(&mut self, author: Address) { self.block.header.set_author(author); }

    	/// Alter the timestamp of the block.
    	pub fn set_timestamp(&mut self, timestamp: u64) { self.block.header.set_timestamp(timestamp); }

    	/// Alter the difficulty for the block.
    	pub fn set_difficulty(&mut self, a: U256) { self.block.header.set_difficulty(a); }

    	/// Alter the gas limit for the block.
    	pub fn set_gas_limit(&mut self, a: U256) { self.block.header.set_gas_limit(a); }

    	/// Alter the gas limit for the block.
    	pub fn set_gas_used(&mut self, a: U256) { self.block.header.set_gas_used(a); }

    	/// Alter the uncles hash the block.
    	pub fn set_uncles_hash(&mut self, h: H256) { self.block.header.set_uncles_hash(h); }

    	/// Alter transactions root for the block.
    	pub fn set_transactions_root(&mut self, h: H256) { self.block.header.set_transactions_root(h); }

    	/// Alter the receipts root for the block.
    	pub fn set_receipts_root(&mut self, h: H256) { self.block.header.set_receipts_root(h); }

    	/// Alter the extra_data for the block.
    	pub fn set_extra_data(&mut self, extra_data: Bytes) -> Result<(), BlockError> {
    		if extra_data.len() > self.engine.maximum_extra_data_size() {
    			Err(BlockError::ExtraDataOutOfBounds(OutOfBounds{min: None, max: Some(self.engine.maximum_extra_data_size()), found: extra_data.len()}))
    		} else {
    			self.block.header.set_extra_data(extra_data);
    			Ok(())
    		}
    	}

    	/// Add an uncle to the block, if possible.
    	///
    	/// NOTE Will check chain constraints and the uncle number but will NOT check
    	/// that the header itself is actually valid.
    	pub fn push_uncle(&mut self, valid_uncle_header: Header) -> Result<(), BlockError> {
    		if self.block.uncles.len() + 1 > self.engine.maximum_uncle_count() {
    			return Err(BlockError::TooManyUncles(OutOfBounds{min: None, max: Some(self.engine.maximum_uncle_count()), found: self.block.uncles.len() + 1}));
    		}
    		// TODO: check number
    		// TODO: check not a direct ancestor (use last_hashes for that)
    		self.block.uncles.push(valid_uncle_header);
    		Ok(())
    	}

    	/// Get the environment info concerning this block.
    	pub fn env_info(&self) -> EnvInfo {
    		// TODO: memoise.
    		EnvInfo {
    			number: self.block.header.number(),
    			author: self.block.header.author().clone(),
    			timestamp: self.block.header.timestamp(),
    			difficulty: self.block.header.difficulty().clone(),
    			last_hashes: self.last_hashes.clone(),
    			gas_used: self.block.receipts.last().map_or(U256::zero(), |r| r.gas_used),
    			gas_limit: self.block.header.gas_limit().clone(),
    		}
    	}

    	/// Push a transaction into the block.
    	///
    	/// If valid, it will be executed, and archived together with the receipt.
    	pub fn push_transaction(&mut self, t: SignedTransaction, h: Option<H256>) -> Result<&Receipt, Error> {
    		if self.block.transactions_set.contains(&t.hash()) {
    			return Err(From::from(TransactionError::AlreadyImported));
    		}

    		let env_info = self.env_info();
    //		info!("env_info says gas_used={}", env_info.gas_used);
    		match self.block.state.apply(&env_info, self.engine, &t, self.block.traces.is_some()) {
    			Ok(outcome) => {
    				self.block.transactions_set.insert(h.unwrap_or_else(||t.hash()));
    				self.block.transactions.push(t.into());
    				let t = outcome.trace;
    				self.block.traces.as_mut().map(|traces| traces.push(t));
    				self.block.receipts.push(outcome.receipt);
    				Ok(self.block.receipts.last().expect("receipt just pushed; qed"))
    			}
    			Err(x) => Err(From::from(x))
    		}
    	}

    	/// Turn this into a `ClosedBlock`.
    	pub fn close(self) -> ClosedBlock {
    		let mut s = self;

    		let unclosed_state = s.block.state.clone();

    		s.engine.on_close_block(&mut s.block);
    		if let Err(e) = s.block.state.commit() {
    			warn!("Encountered error on state commit: {}", e);
    		}
    		s.block.header.set_transactions_root(ordered_trie_root(s.block.transactions.iter().map(|e| e.rlp_bytes().to_vec())));
    		let uncle_bytes = s.block.uncles.iter().fold(RlpStream::new_list(s.block.uncles.len()), |mut s, u| {s.append_raw(&u.rlp(Seal::With), 1); s} ).out();
    		s.block.header.set_uncles_hash(uncle_bytes.sha3());
    		s.block.header.set_state_root(s.block.state.root().clone());
    		s.block.header.set_receipts_root(ordered_trie_root(s.block.receipts.iter().map(|r| r.rlp_bytes().to_vec())));
    		s.block.header.set_log_bloom(s.block.receipts.iter().fold(LogBloom::zero(), |mut b, r| {b = &b | &r.log_bloom; b})); //TODO: use |= operator
    		s.block.header.set_gas_used(s.block.receipts.last().map_or(U256::zero(), |r| r.gas_used));

    		ClosedBlock {
    			block: s.block,
    			uncle_bytes: uncle_bytes,
    			last_hashes: s.last_hashes,
    			unclosed_state: unclosed_state,
    		}
    	}

    	/// Turn this into a `LockedBlock`.
    	pub fn close_and_lock(self) -> LockedBlock {
    		let mut s = self;

    		s.engine.on_close_block(&mut s.block);

    		if let Err(e) = s.block.state.commit() {
    			warn!("Encountered error on state commit: {}", e);
    		}
    		if s.block.header.transactions_root().is_zero() || s.block.header.transactions_root() == &SHA3_NULL_RLP {
    			s.block.header.set_transactions_root(ordered_trie_root(s.block.transactions.iter().map(|e| e.rlp_bytes().to_vec())));
    		}
    		let uncle_bytes = s.block.uncles.iter().fold(RlpStream::new_list(s.block.uncles.len()), |mut s, u| {s.append_raw(&u.rlp(Seal::With), 1); s} ).out();
    		if s.block.header.uncles_hash().is_zero() {
    			s.block.header.set_uncles_hash(uncle_bytes.sha3());
    		}
    		if s.block.header.receipts_root().is_zero() || s.block.header.receipts_root() == &SHA3_NULL_RLP {
    			s.block.header.set_receipts_root(ordered_trie_root(s.block.receipts.iter().map(|r| r.rlp_bytes().to_vec())));
    		}

    		s.block.header.set_state_root(s.block.state.root().clone());
    		s.block.header.set_log_bloom(s.block.receipts.iter().fold(LogBloom::zero(), |mut b, r| {b = &b | &r.log_bloom; b})); //TODO: use |= operator
    		s.block.header.set_gas_used(s.block.receipts.last().map_or(U256::zero(), |r| r.gas_used));

    		LockedBlock {
    			block: s.block,
    			uncle_bytes: uncle_bytes,
    		}
    	}

    	#[cfg(test)]
    	/// Return mutable block reference. To be used in tests only.
    	pub fn block_mut (&mut self) -> &mut ExecutedBlock { &mut self.block }
    }

    impl<'x> IsBlock for OpenBlock<'x> {
    	fn block(&self) -> &ExecutedBlock { &self.block }
    }

    impl<'x> IsBlock for ClosedBlock {
    	fn block(&self) -> &ExecutedBlock { &self.block }
    }

    impl<'x> IsBlock for LockedBlock {
    	fn block(&self) -> &ExecutedBlock { &self.block }
    }

    impl ClosedBlock {
    	/// Get the hash of the header without seal arguments.
    	pub fn hash(&self) -> H256 { self.header().rlp_sha3(Seal::Without) }

    	/// Turn this into a `LockedBlock`, unable to be reopened again.
    	pub fn lock(self) -> LockedBlock {
    		LockedBlock {
    			block: self.block,
    			uncle_bytes: self.uncle_bytes,
    		}
    	}

    	/// Given an engine reference, reopen the `ClosedBlock` into an `OpenBlock`.
    	pub fn reopen(self, engine: &Engine) -> OpenBlock {
    		// revert rewards (i.e. set state back at last transaction's state).
    		let mut block = self.block;
    		block.state = self.unclosed_state;
    		OpenBlock {
    			block: block,
    			engine: engine,
    			last_hashes: self.last_hashes,
    		}
    	}
    }

    impl LockedBlock {
    	/// Get the hash of the header without seal arguments.
    	pub fn hash(&self) -> H256 { self.header().rlp_sha3(Seal::Without) }

    	/// Provide a valid seal in order to turn this into a `SealedBlock`.
    	///
    	/// NOTE: This does not check the validity of `seal` with the engine.
    	pub fn seal(self, engine: &Engine, seal: Vec<Bytes>) -> Result<SealedBlock, BlockError> {
    		let mut s = self;
    		if seal.len() != engine.seal_fields() {
    			return Err(BlockError::InvalidSealArity(Mismatch{expected: engine.seal_fields(), found: seal.len()}));
    		}
    		s.block.header.set_seal(seal);
    		Ok(SealedBlock { block: s.block, uncle_bytes: s.uncle_bytes })
    	}

    	/// Provide a valid seal in order to turn this into a `SealedBlock`.
    	/// This does check the validity of `seal` with the engine.
    	/// Returns the `ClosedBlock` back again if the seal is no good.
    	pub fn try_seal(self, engine: &Engine, seal: Vec<Bytes>) -> Result<SealedBlock, (Error, LockedBlock)> {
    		let mut s = self;
    		s.block.header.set_seal(seal);
    		match engine.verify_block_seal(&s.block.header) {
    			Err(e) => Err((e, s)),
    			_ => Ok(SealedBlock { block: s.block, uncle_bytes: s.uncle_bytes }),
    		}
    	}
    }

    impl Drain for LockedBlock {
    	/// Drop this object and return the underlieing database.
    	fn drain(self) -> StateDB {
    		self.block.state.drop().1
    	}
    }

    impl SealedBlock {
    	/// Get the RLP-encoding of the block.
    	pub fn rlp_bytes(&self) -> Bytes {
    		let mut block_rlp = RlpStream::new_list(3);
    		self.block.header.stream_rlp(&mut block_rlp, Seal::With);
    		block_rlp.append(&self.block.transactions);
    		block_rlp.append_raw(&self.uncle_bytes, 1);
    		block_rlp.out()
    	}
    }

    impl Drain for SealedBlock {
    	/// Drop this object and return the underlieing database.
    	fn drain(self) -> StateDB {
    		self.block.state.drop().1
    	}
    }

    impl IsBlock for SealedBlock {
    	fn block(&self) -> &ExecutedBlock { &self.block }
    }

    /// Enact the block given by block header, transactions and uncles
    #[cfg_attr(feature="dev", allow(too_many_arguments))]
    pub fn enact(
    	header: &Header,
    	transactions: &[SignedTransaction],
    	uncles: &[Header],
    	engine: &Engine,
    	tracing: bool,
    	db: StateDB,
    	parent: &Header,
    	last_hashes: Arc<LastHashes>,
    	factories: Factories,
    ) -> Result<LockedBlock, Error> {
    	{
    		if ::log::max_log_level() >= ::log::LogLevel::Trace {
    			let s = State::from_existing(db.boxed_clone(), parent.state_root().clone(), engine.account_start_nonce(), factories.clone())?;
    			trace!(target: "enact", "num={}, root={}, author={}, author_balance={}\n", header.number(), s.root(), header.author(), s.balance(&header.author()));
    		}
    	}

    	let mut b = OpenBlock::new(engine, factories, tracing, db, parent, last_hashes, Address::new(), (3141562.into(), 31415620.into()), vec![])?;
    	b.set_difficulty(*header.difficulty());
    	b.set_gas_limit(*header.gas_limit());
    	b.set_timestamp(header.timestamp());
    	b.set_author(header.author().clone());
    	b.set_extra_data(header.extra_data().clone()).unwrap_or_else(|e| warn!("Couldn't set extradata: {}. Ignoring.", e));
    	b.set_uncles_hash(header.uncles_hash().clone());
    	b.set_transactions_root(header.transactions_root().clone());
    	b.set_receipts_root(header.receipts_root().clone());

    	push_transactions(&mut b, transactions)?;
    	for u in uncles {
    		b.push_uncle(u.clone())?;
    	}
    	Ok(b.close_and_lock())
    }

    #[inline]
    #[cfg(not(feature = "slow-blocks"))]
    fn push_transactions(block: &mut OpenBlock, transactions: &[SignedTransaction]) -> Result<(), Error> {
    	for t in transactions {
    		block.push_transaction(t.clone(), None)?;
    	}
    	Ok(())
    }

    #[cfg(feature = "slow-blocks")]
    fn push_transactions(block: &mut OpenBlock, transactions: &[SignedTransaction]) -> Result<(), Error> {
    	use std::time;

    	let slow_tx = option_env!("SLOW_TX_DURATION").and_then(|v| v.parse().ok()).unwrap_or(100);
    	for t in transactions {
    		let hash = t.hash();
    		let start = time::Instant::now();
    		block.push_transaction(t.clone(), None)?;
    		let took = start.elapsed();
    		let took_ms = took.as_secs() * 1000 + took.subsec_nanos() as u64 / 1000000;
    		if took > time::Duration::from_millis(slow_tx) {
    			warn!("Heavy ({} ms) transaction in block {:?}: {:?}", took_ms, block.header().number(), hash);
    		}
    		debug!(target: "tx", "Transaction {:?} took: {} ms", hash, took_ms);
    	}
    	Ok(())
    }

    // TODO [ToDr] Pass `PreverifiedBlock` by move, this will avoid unecessary allocation
    /// Enact the block given by `block_bytes` using `engine` on the database `db` with given `parent` block header
    #[cfg_attr(feature="dev", allow(too_many_arguments))]
    pub fn enact_verified(
    	block: &PreverifiedBlock,
    	engine: &Engine,
    	tracing: bool,
    	db: StateDB,
    	parent: &Header,
    	last_hashes: Arc<LastHashes>,
    	factories: Factories,
    ) -> Result<LockedBlock, Error> {
    	let view = BlockView::new(&block.bytes);
    	enact(&block.header, &block.transactions, &view.uncles(), engine, tracing, db, parent, last_hashes, factories)
    }

    #[cfg(test)]
    mod tests {
    	use tests::helpers::*;
    	use super::*;
    	use engines::Engine;
    	use env_info::LastHashes;
    	use error::Error;
    	use header::Header;
    	use factory::Factories;
    	use state_db::StateDB;
    	use views::BlockView;
    	use util::Address;
    	use util::hash::FixedHash;
    	use std::sync::Arc;
    	use transaction::SignedTransaction;

    	/// Enact the block given by `block_bytes` using `engine` on the database `db` with given `parent` block header
    	#[cfg_attr(feature="dev", allow(too_many_arguments))]
    	fn enact_bytes(
    		block_bytes: &[u8],
    		engine: &Engine,
    		tracing: bool,
    		db: StateDB,
    		parent: &Header,
    		last_hashes: Arc<LastHashes>,
    		factories: Factories,
    	) -> Result<LockedBlock, Error> {
    		let block = BlockView::new(block_bytes);
    		let header = block.header();
    		let transactions: Result<Vec<_>, Error> = block.transactions().into_iter().map(SignedTransaction::new).collect();
    		let transactions = transactions?;
    		enact(&header, &transactions, &block.uncles(), engine, tracing, db, parent, last_hashes, factories)
    	}

    	/// Enact the block given by `block_bytes` using `engine` on the database `db` with given `parent` block header. Seal the block aferwards
    	#[cfg_attr(feature="dev", allow(too_many_arguments))]
    	fn enact_and_seal(
    		block_bytes: &[u8],
    		engine: &Engine,
    		tracing: bool,
    		db: StateDB,
    		parent: &Header,
    		last_hashes: Arc<LastHashes>,
    		factories: Factories,
    	) -> Result<SealedBlock, Error> {
    		let header = BlockView::new(block_bytes).header_view();
    		Ok(enact_bytes(block_bytes, engine, tracing, db, parent, last_hashes, factories)?.seal(engine, header.seal())?)
    	}

    	#[test]
    	fn open_block() {
    		use spec::*;
    		let spec = Spec::new_test();
    		let genesis_header = spec.genesis_header();
    		let mut db_result = get_temp_state_db();
    		let db = spec.ensure_db_good(db_result.take(), &Default::default()).unwrap();
    		let last_hashes = Arc::new(vec![genesis_header.hash()]);
    		let b = OpenBlock::new(&*spec.engine, Default::default(), false, db, &genesis_header, last_hashes, Address::zero(), (3141562.into(), 31415620.into()), vec![]).unwrap();
    		let b = b.close_and_lock();
    		let _ = b.seal(&*spec.engine, vec![]);
    	}

    	#[test]
    	fn enact_block() {
    		use spec::*;
    		let spec = Spec::new_test();
    		let engine = &*spec.engine;
    		let genesis_header = spec.genesis_header();

    		let mut db_result = get_temp_state_db();
    		let db = spec.ensure_db_good(db_result.take(), &Default::default()).unwrap();
    		let last_hashes = Arc::new(vec![genesis_header.hash()]);
    		let b = OpenBlock::new(engine, Default::default(), false, db, &genesis_header, last_hashes.clone(), Address::zero(), (3141562.into(), 31415620.into()), vec![]).unwrap()
    			.close_and_lock().seal(engine, vec![]).unwrap();
    		let orig_bytes = b.rlp_bytes();
    		let orig_db = b.drain();

    		let mut db_result = get_temp_state_db();
    		let db = spec.ensure_db_good(db_result.take(), &Default::default()).unwrap();
    		let e = enact_and_seal(&orig_bytes, engine, false, db, &genesis_header, last_hashes, Default::default()).unwrap();

    		assert_eq!(e.rlp_bytes(), orig_bytes);

    		let db = e.drain();
    		assert_eq!(orig_db.journal_db().keys(), db.journal_db().keys());
    		assert!(orig_db.journal_db().keys().iter().filter(|k| orig_db.journal_db().get(k.0) != db.journal_db().get(k.0)).next() == None);
    	}

    	#[test]
    	fn enact_block_with_uncle() {
    		use spec::*;
    		let spec = Spec::new_test();
    		let engine = &*spec.engine;
    		let genesis_header = spec.genesis_header();

    		let mut db_result = get_temp_state_db();
    		let db = spec.ensure_db_good(db_result.take(), &Default::default()).unwrap();
    		let last_hashes = Arc::new(vec![genesis_header.hash()]);
    		let mut open_block = OpenBlock::new(engine, Default::default(), false, db, &genesis_header, last_hashes.clone(), Address::zero(), (3141562.into(), 31415620.into()), vec![]).unwrap();
    		let mut uncle1_header = Header::new();
    		uncle1_header.set_extra_data(b"uncle1".to_vec());
    		let mut uncle2_header = Header::new();
    		uncle2_header.set_extra_data(b"uncle2".to_vec());
    		open_block.push_uncle(uncle1_header).unwrap();
    		open_block.push_uncle(uncle2_header).unwrap();
    		let b = open_block.close_and_lock().seal(engine, vec![]).unwrap();

    		let orig_bytes = b.rlp_bytes();
    		let orig_db = b.drain();

    		let mut db_result = get_temp_state_db();
    		let db = spec.ensure_db_good(db_result.take(), &Default::default()).unwrap();
    		let e = enact_and_seal(&orig_bytes, engine, false, db, &genesis_header, last_hashes, Default::default()).unwrap();

    		let bytes = e.rlp_bytes();
    		assert_eq!(bytes, orig_bytes);
    		let uncles = BlockView::new(&bytes).uncles();
    		assert_eq!(uncles[1].extra_data(), b"uncle2");

    		let db = e.drain();
    		assert_eq!(orig_db.journal_db().keys(), db.journal_db().keys());
    		assert!(orig_db.journal_db().keys().iter().filter(|k| orig_db.journal_db().get(k.0) != db.journal_db().get(k.0)).next() == None);
    	}
    }

# Help

## Keyboard Shortcuts

?
  Show this help dialog
S
  Focus the search field
⇤
  Move up in search results
⇥
  Move down in search results
⏎
  Go to active search result
+
  Collapse/expand all sections

## Search Tricks

Prefix searches with a type followed by a colon (e.g. `fn:`) to restrict the search to a given type.

Accepted types are: `fn`, `mod`, `struct`, `enum`, `trait`, `type`, `macro`, and `const`.

Search functions by type signature (e.g. `vec -> usize` or `* -> vec`)