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    // 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/>.

    use std::sync::Arc;
    use std::net::{TcpListener};
    use ctrlc::CtrlC;
    use fdlimit::raise_fd_limit;
    use ethcore_rpc::{NetworkSettings, is_major_importing};
    use ethsync::NetworkConfiguration;
    use util::{Colour, version, RotatingLogger, Mutex, Condvar};
    use io::{MayPanic, ForwardPanic, PanicHandler};
    use ethcore_logger::{Config as LogConfig};
    use ethcore::miner::{StratumOptions, Stratum};
    use ethcore::client::{Mode, DatabaseCompactionProfile, VMType, BlockChainClient};
    use ethcore::service::ClientService;
    use ethcore::account_provider::AccountProvider;
    use ethcore::miner::{Miner, MinerService, ExternalMiner, MinerOptions};
    use ethcore::snapshot;
    use ethcore::verification::queue::VerifierSettings;
    use ethsync::SyncConfig;
    use informant::Informant;
    use updater::{UpdatePolicy, Updater};
    use parity_reactor::EventLoop;
    use hash_fetch::fetch::{Fetch, Client as FetchClient};

    use rpc::{HttpConfiguration, IpcConfiguration};
    use params::{
    	SpecType, Pruning, AccountsConfig, GasPricerConfig, MinerExtras, Switch,
    	tracing_switch_to_bool, fatdb_switch_to_bool, mode_switch_to_bool
    };
    use helpers::{to_client_config, execute_upgrades, passwords_from_files};
    use upgrade::upgrade_key_location;
    use dir::Directories;
    use cache::CacheConfig;
    use user_defaults::UserDefaults;
    use dapps;
    use signer;
    use modules;
    use rpc_apis;
    use rpc;
    use url;

    // how often to take periodic snapshots.
    const SNAPSHOT_PERIOD: u64 = 10000;

    // how many blocks to wait before starting a periodic snapshot.
    const SNAPSHOT_HISTORY: u64 = 100;

    // Pops along with error messages when a password is missing or invalid.
    const VERIFY_PASSWORD_HINT: &'static str = "Make sure valid password is present in files passed using `--password` or in the configuration file.";

    #[derive(Debug, PartialEq)]
    pub struct RunCmd {
    	pub cache_config: CacheConfig,
    	pub dirs: Directories,
    	pub spec: SpecType,
    	pub pruning: Pruning,
    	pub pruning_history: u64,
    	pub pruning_memory: usize,
    	/// Some if execution should be daemonized. Contains pid_file path.
    	pub daemon: Option<String>,
    	pub logger_config: LogConfig,
    	pub miner_options: MinerOptions,
    	pub http_conf: HttpConfiguration,
    	pub ipc_conf: IpcConfiguration,
    	pub net_conf: NetworkConfiguration,
    	pub network_id: Option<u64>,
    	pub warp_sync: bool,
    	pub acc_conf: AccountsConfig,
    	pub gas_pricer: GasPricerConfig,
    	pub miner_extras: MinerExtras,
    	pub update_policy: UpdatePolicy,
    	pub mode: Option<Mode>,
    	pub tracing: Switch,
    	pub fat_db: Switch,
    	pub compaction: DatabaseCompactionProfile,
    	pub wal: bool,
    	pub vm_type: VMType,
    	pub geth_compatibility: bool,
    	pub ui_address: Option<(String, u16)>,
    	pub net_settings: NetworkSettings,
    	pub dapps_conf: dapps::Configuration,
    	pub signer_conf: signer::Configuration,
    	pub dapp: Option<String>,
    	pub ui: bool,
    	pub name: String,
    	pub custom_bootnodes: bool,
    	pub stratum: Option<StratumOptions>,
    	pub no_periodic_snapshot: bool,
    	pub check_seal: bool,
    	pub download_old_blocks: bool,
    	pub verifier_settings: VerifierSettings,
    }

    pub fn open_ui(dapps_conf: &dapps::Configuration, signer_conf: &signer::Configuration) -> Result<(), String> {
    	if !dapps_conf.enabled {
    		return Err("Cannot use UI command with Dapps turned off.".into())
    	}

    	if !signer_conf.enabled {
    		return Err("Cannot use UI command with UI turned off.".into())
    	}

    	let token = signer::generate_token_and_url(signer_conf)?;
    	// Open a browser
    	url::open(&token.url);
    	// Print a message
    	println!("{}", token.message);
    	Ok(())
    }

    pub fn open_dapp(dapps_conf: &dapps::Configuration, dapp: &str) -> Result<(), String> {
    	if !dapps_conf.enabled {
    		return Err("Cannot use DAPP command with Dapps turned off.".into())
    	}

    	let url = format!("http://{}:{}/{}/", dapps_conf.interface, dapps_conf.port, dapp);
    	url::open(&url);
    	Ok(())
    }

    pub fn execute(cmd: RunCmd, can_restart: bool, logger: Arc<RotatingLogger>) -> Result<bool, String> {
    	if cmd.ui && cmd.dapps_conf.enabled {
    		// Check if Parity is already running
    		let addr = format!("{}:{}", cmd.dapps_conf.interface, cmd.dapps_conf.port);
    		if !TcpListener::bind(&addr as &str).is_ok() {
    			return open_ui(&cmd.dapps_conf, &cmd.signer_conf).map(|_| false);
    		}
    	}

    	// set up panic handler
    	let panic_handler = PanicHandler::new_in_arc();

    	// increase max number of open files
    	raise_fd_limit();

    	// load spec
    	let spec = cmd.spec.spec()?;

    	// load genesis hash
    	let genesis_hash = spec.genesis_header().hash();

    	// database paths
    	let db_dirs = cmd.dirs.database(genesis_hash, cmd.spec.legacy_fork_name(), spec.data_dir.clone());

    	// user defaults path
    	let user_defaults_path = db_dirs.user_defaults_path();

    	// load user defaults
    	let mut user_defaults = UserDefaults::load(&user_defaults_path)?;

    	// select pruning algorithm
    	let algorithm = cmd.pruning.to_algorithm(&user_defaults);

    	// check if tracing is on
    	let tracing = tracing_switch_to_bool(cmd.tracing, &user_defaults)?;

    	// check if fatdb is on
    	let fat_db = fatdb_switch_to_bool(cmd.fat_db, &user_defaults, algorithm)?;

    	// get the mode
    	let mode = mode_switch_to_bool(cmd.mode, &user_defaults)?;
    	trace!(target: "mode", "mode is {:?}", mode);
    	let network_enabled = match mode { Mode::Dark(_) | Mode::Off => false, _ => true, };

    	// get the update policy
    	let update_policy = cmd.update_policy;

    	// prepare client and snapshot paths.
    	let client_path = db_dirs.client_path(algorithm);
    	let snapshot_path = db_dirs.snapshot_path();

    	// execute upgrades
    	execute_upgrades(&cmd.dirs.base, &db_dirs, algorithm, cmd.compaction.compaction_profile(db_dirs.db_root_path().as_path()))?;

    	// create dirs used by parity
    	cmd.dirs.create_dirs(cmd.dapps_conf.enabled, cmd.signer_conf.enabled)?;

    	// run in daemon mode
    	if let Some(pid_file) = cmd.daemon {
    		daemonize(pid_file)?;
    	}

    	// display info about used pruning algorithm
    	info!("Starting {}", Colour::White.bold().paint(version()));
    	info!("State DB configuration: {}{}{}",
    		Colour::White.bold().paint(algorithm.as_str()),
    		match fat_db {
    			true => Colour::White.bold().paint(" +Fat").to_string(),
    			false => "".to_owned(),
    		},
    		match tracing {
    			true => Colour::White.bold().paint(" +Trace").to_string(),
    			false => "".to_owned(),
    		}
    	);
    	info!("Operating mode: {}", Colour::White.bold().paint(format!("{}", mode)));

    	// display warning about using experimental journaldb alorithm
    	if !algorithm.is_stable() {
    		warn!("Your chosen strategy is {}! You can re-run with --pruning to change.", Colour::Red.bold().paint("unstable"));
    	}

    	// create sync config
    	let mut sync_config = SyncConfig::default();
    	sync_config.network_id = match cmd.network_id {
    		Some(id) => id,
    		None => spec.network_id(),
    	};
    	if spec.subprotocol_name().len() != 3 {
    		warn!("Your chain specification's subprotocol length is not 3. Ignoring.");
    	} else {
    		sync_config.subprotocol_name.clone_from_slice(spec.subprotocol_name().as_bytes());
    	}
    	sync_config.fork_block = spec.fork_block();
    	sync_config.warp_sync = cmd.warp_sync;
    	sync_config.download_old_blocks = cmd.download_old_blocks;

    	let passwords = passwords_from_files(&cmd.acc_conf.password_files)?;

    	// prepare account provider
    	let account_provider = Arc::new(prepare_account_provider(&cmd.spec, &cmd.dirs, &spec.data_dir, cmd.acc_conf, &passwords)?);

    	// create miner
    	let initial_min_gas_price = cmd.gas_pricer.initial_min();
    	let miner = Miner::new(cmd.miner_options, cmd.gas_pricer.into(), &spec, Some(account_provider.clone()));
    	miner.set_author(cmd.miner_extras.author);
    	miner.set_gas_floor_target(cmd.miner_extras.gas_floor_target);
    	miner.set_gas_ceil_target(cmd.miner_extras.gas_ceil_target);
    	miner.set_extra_data(cmd.miner_extras.extra_data);
    	miner.set_transactions_limit(cmd.miner_extras.transactions_limit);
    	miner.set_minimal_gas_price(initial_min_gas_price);
    	miner.recalibrate_minimal_gas_price();
    	let engine_signer = cmd.miner_extras.engine_signer;

    	if engine_signer != Default::default() {
    		// Check if engine signer exists
    		if !account_provider.has_account(engine_signer).unwrap_or(false) {
    			return Err(format!("Consensus signer account not found for the current chain. {}", build_create_account_hint(&cmd.spec, &cmd.dirs.keys)));
    		}

    		// Check if any passwords have been read from the password file(s)
    		if passwords.is_empty() {
    			return Err(format!("No password found for the consensus signer {}. {}", engine_signer, VERIFY_PASSWORD_HINT));
    		}

    		// Attempt to sign in the engine signer.
    		if !passwords.into_iter().any(|p| miner.set_engine_signer(engine_signer, p).is_ok()) {
    			return Err(format!("No valid password for the consensus signer {}. {}", engine_signer, VERIFY_PASSWORD_HINT));
    		}
    	}

    	// create client config
    	let mut client_config = to_client_config(
    		&cmd.cache_config,
    		mode.clone(),
    		tracing,
    		fat_db,
    		cmd.compaction,
    		cmd.wal,
    		cmd.vm_type,
    		cmd.name,
    		algorithm,
    		cmd.pruning_history,
    		cmd.pruning_memory,
    		cmd.check_seal,
    	);

    	client_config.queue.verifier_settings = cmd.verifier_settings;

    	// set up bootnodes
    	let mut net_conf = cmd.net_conf;
    	if !cmd.custom_bootnodes {
    		net_conf.boot_nodes = spec.nodes.clone();
    	}

    	// set network path.
    	net_conf.net_config_path = Some(db_dirs.network_path().to_string_lossy().into_owned());

    	// create supervisor
    	let mut hypervisor = modules::hypervisor(&cmd.dirs.ipc_path());

    	// create client service.
    	let service = ClientService::start(
    		client_config,
    		&spec,
    		&client_path,
    		&snapshot_path,
    		&cmd.dirs.ipc_path(),
    		miner.clone(),
    	).map_err(|e| format!("Client service error: {:?}", e))?;

    	// drop the spec to free up genesis state.
    	drop(spec);

    	// forward panics from service
    	panic_handler.forward_from(&service);

    	// take handle to client
    	let client = service.client();
    	let snapshot_service = service.snapshot_service();

    	// create external miner
    	let external_miner = Arc::new(ExternalMiner::default());

    	// start stratum
    	if let Some(ref stratum_config) = cmd.stratum {
    		Stratum::register(stratum_config, miner.clone(), Arc::downgrade(&client))
    			.map_err(|e| format!("Stratum start error: {:?}", e))?;
    	}

    	// create sync object
    	let (sync_provider, manage_network, chain_notify) = modules::sync(
    		&mut hypervisor,
    		sync_config,
    		net_conf.into(),
    		client.clone(),
    		snapshot_service.clone(),
    		client.clone(),
    		&cmd.logger_config,
    	).map_err(|e| format!("Sync error: {}", e))?;

    	service.add_notify(chain_notify.clone());

    	// start network
    	if network_enabled {
    		chain_notify.start();
    	}

    	// spin up event loop
    	let event_loop = EventLoop::spawn();

    	// fetch service
    	let fetch = FetchClient::new().map_err(|e| format!("Error starting fetch client: {:?}", e))?;

    	// the updater service
    	let updater = Updater::new(
    		Arc::downgrade(&(service.client() as Arc<BlockChainClient>)),
    		Arc::downgrade(&sync_provider),
    		update_policy,
    		fetch.clone(),
    		event_loop.remote(),
    	);
    	service.add_notify(updater.clone());

    	// set up dependencies for rpc servers
    	let signer_path = cmd.signer_conf.signer_path.clone();
    	let deps_for_rpc_apis = Arc::new(rpc_apis::Dependencies {
    		signer_service: Arc::new(rpc_apis::SignerService::new(move || {
    			signer::generate_new_token(signer_path.clone()).map_err(|e| format!("{:?}", e))
    		}, cmd.ui_address)),
    		snapshot: snapshot_service.clone(),
    		client: client.clone(),
    		sync: sync_provider.clone(),
    		net: manage_network.clone(),
    		secret_store: account_provider.clone(),
    		miner: miner.clone(),
    		external_miner: external_miner.clone(),
    		logger: logger.clone(),
    		settings: Arc::new(cmd.net_settings.clone()),
    		net_service: manage_network.clone(),
    		updater: updater.clone(),
    		geth_compatibility: cmd.geth_compatibility,
    		dapps_interface: match cmd.dapps_conf.enabled {
    			true => Some(cmd.dapps_conf.interface.clone()),
    			false => None,
    		},
    		dapps_port: match cmd.dapps_conf.enabled {
    			true => Some(cmd.dapps_conf.port),
    			false => None,
    		},
    		fetch: fetch.clone(),
    	});

    	let dependencies = rpc::Dependencies {
    		panic_handler: panic_handler.clone(),
    		apis: deps_for_rpc_apis.clone(),
    		remote: event_loop.raw_remote(),
    	};

    	// start rpc servers
    	let http_server = rpc::new_http(cmd.http_conf, &dependencies)?;
    	let ipc_server = rpc::new_ipc(cmd.ipc_conf, &dependencies)?;

    	// the dapps server
    	let dapps_deps = dapps::Dependencies {
    		panic_handler: panic_handler.clone(),
    		apis: deps_for_rpc_apis.clone(),
    		client: client.clone(),
    		sync: sync_provider.clone(),
    		remote: event_loop.raw_remote(),
    		fetch: fetch.clone(),
    		signer: deps_for_rpc_apis.signer_service.clone(),
    	};
    	let dapps_server = dapps::new(cmd.dapps_conf.clone(), dapps_deps)?;

    	// the signer server
    	let signer_deps = signer::Dependencies {
    		panic_handler: panic_handler.clone(),
    		apis: deps_for_rpc_apis.clone(),
    		remote: event_loop.raw_remote(),
    	};
    	let signer_server = signer::start(cmd.signer_conf.clone(), signer_deps)?;

    	// the informant
    	let informant = Arc::new(Informant::new(
    		service.client(),
    		Some(sync_provider.clone()),
    		Some(manage_network.clone()),
    		Some(snapshot_service.clone()),
    		cmd.logger_config.color
    	));
    	service.add_notify(informant.clone());
    	service.register_io_handler(informant.clone()).map_err(|_| "Unable to register informant handler".to_owned())?;

    	// save user defaults
    	user_defaults.pruning = algorithm;
    	user_defaults.tracing = tracing;
    	user_defaults.fat_db = fat_db;
    	user_defaults.mode = mode;
    	user_defaults.save(&user_defaults_path)?;

    	// tell client how to save the default mode if it gets changed.
    	client.on_mode_change(move |mode: &Mode| {
    		user_defaults.mode = mode.clone();
    		let _ = user_defaults.save(&user_defaults_path);	// discard failures - there's nothing we can do
    	});

    	// the watcher must be kept alive.
    	let _watcher = match cmd.no_periodic_snapshot {
    		true => None,
    		false => {
    			let sync = sync_provider.clone();
    			let watcher = Arc::new(snapshot::Watcher::new(
    				service.client(),
    				move || is_major_importing(Some(sync.status().state), client.queue_info()),
    				service.io().channel(),
    				SNAPSHOT_PERIOD,
    				SNAPSHOT_HISTORY,
    			));

    			service.add_notify(watcher.clone());
    			Some(watcher)
    		},
    	};

    	// start ui
    	if cmd.ui {
    		open_ui(&cmd.dapps_conf, &cmd.signer_conf)?;
    	}

    	if let Some(dapp) = cmd.dapp {
    		open_dapp(&cmd.dapps_conf, &dapp)?;
    	}

    	// Handle exit
    	let restart = wait_for_exit(panic_handler, Some(updater), can_restart);

    	// drop this stuff as soon as exit detected.
    	drop((http_server, ipc_server, dapps_server, signer_server, event_loop));

    	info!("Finishing work, please wait...");

    	// to make sure timer does not spawn requests while shutdown is in progress
    	informant.shutdown();
    	// just Arc is dropping here, to allow other reference release in its default time
    	drop(informant);

    	// hypervisor should be shutdown first while everything still works and can be
    	// terminated gracefully
    	drop(hypervisor);

    	Ok(restart)
    }

    #[cfg(not(windows))]
    fn daemonize(pid_file: String) -> Result<(), String> {
    	extern crate daemonize;

    	daemonize::Daemonize::new()
    		.pid_file(pid_file)
    		.chown_pid_file(true)
    		.start()
    		.map(|_| ())
    		.map_err(|e| format!("Couldn't daemonize; {}", e))
    }

    #[cfg(windows)]
    fn daemonize(_pid_file: String) -> Result<(), String> {
    	Err("daemon is no supported on windows".into())
    }

    fn prepare_account_provider(spec: &SpecType, dirs: &Directories, data_dir: &str, cfg: AccountsConfig, passwords: &[String]) -> Result<AccountProvider, String> {
    	use ethcore::ethstore::EthStore;
    	use ethcore::ethstore::dir::RootDiskDirectory;

    	let path = dirs.keys_path(data_dir);
    	upgrade_key_location(&dirs.legacy_keys_path(cfg.testnet), &path);
    	let dir = Box::new(RootDiskDirectory::create(&path).map_err(|e| format!("Could not open keys directory: {}", e))?);
    	let account_provider = AccountProvider::new(Box::new(
    		EthStore::open_with_iterations(dir, cfg.iterations).map_err(|e| format!("Could not open keys directory: {}", e))?
    	));

    	for a in cfg.unlocked_accounts {
    		// Check if the account exists
    		if !account_provider.has_account(a).unwrap_or(false) {
    			return Err(format!("Account {} not found for the current chain. {}", a, build_create_account_hint(spec, &dirs.keys)));
    		}

    		// Check if any passwords have been read from the password file(s)
    		if passwords.is_empty() {
    			return Err(format!("No password found to unlock account {}. {}", a, VERIFY_PASSWORD_HINT));
    		}

    		if !passwords.iter().any(|p| account_provider.unlock_account_permanently(a, (*p).clone()).is_ok()) {
    			return Err(format!("No valid password to unlock account {}. {}", a, VERIFY_PASSWORD_HINT));
    		}
    	}

    	Ok(account_provider)
    }

    // Construct an error `String` with an adaptive hint on how to create an account.
    fn build_create_account_hint(spec: &SpecType, keys: &str) -> String {
    	format!("You can create an account via RPC, UI or `parity account new --chain {} --keys-path {}`.", spec, keys)
    }

    fn wait_for_exit(
    	panic_handler: Arc<PanicHandler>,
    	updater: Option<Arc<Updater>>,
    	can_restart: bool
    ) -> bool {
    	let exit = Arc::new((Mutex::new(false), Condvar::new()));

    	// Handle possible exits
    	let e = exit.clone();
    	CtrlC::set_handler(move || { e.1.notify_all(); });

    	// Handle panics
    	let e = exit.clone();
    	panic_handler.on_panic(move |_reason| { e.1.notify_all(); });

    	if let Some(updater) = updater {
    		// Handle updater wanting to restart us
    		if can_restart {
    			let e = exit.clone();
    			updater.set_exit_handler(move || { *e.0.lock() = true; e.1.notify_all(); });
    		} else {
    			updater.set_exit_handler(|| info!("Update installed; ready for restart."));
    		}
    	}

    	// Wait for signal
    	let mut l = exit.0.lock();
    	let _ = exit.1.wait(&mut l);
    	*l
    }

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