7370776af1
* use bloomchain crate in blockchain module. remove obsole chainfilter submodule * update database version to 6.0 * removed redundant line * simple db migration * make migration slightly more functional * bloomchain migration * migration version is just a single unsigned integer * updated migration v6 * parity migration * db migration * removed hardcoded migration dir * replace ptr::copy with clone_from_slice, removed potential endianess problem from trace/db.rs * removed superfluous line * blockchains log blooms config is not exposed any more
118 lines
3.1 KiB
Rust
118 lines
3.1 KiB
Rust
// Copyright 2015, 2016 Ethcore (UK) Ltd.
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// This file is part of Parity.
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// Parity is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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// Parity is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with Parity. If not, see <http://www.gnu.org/licenses/>.
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//! Migration manager
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use std::collections::BTreeMap;
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use migration::{Migration, Destination};
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/// Migration error.
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#[derive(Debug)]
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pub enum Error {
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/// Error returned when it is impossible to add new migration rules.
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CannotAddMigration,
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/// Error returned when migration from specific version can not be performed.
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MigrationImpossible,
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/// Custom error.
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Custom(String),
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}
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/// Migration config.
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pub struct Config {
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/// Defines how many elements should be migrated at once.
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pub batch_size: usize,
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}
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impl Default for Config {
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fn default() -> Self {
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Config {
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batch_size: 1024,
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}
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}
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}
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/// Manages database migration.
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pub struct Manager {
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config: Config,
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migrations: Vec<Box<Migration>>,
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}
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impl Manager {
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/// Creates new migration manager with given configuration.
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pub fn new(config: Config) -> Self {
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Manager {
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config: config,
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migrations: vec![]
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}
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}
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/// Adds new migration rules.
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pub fn add_migration<T>(&mut self, migration: T) -> Result<(), Error> where T: Migration {
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let version_match = match self.migrations.last() {
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Some(last) => last.version() + 1 == migration.version(),
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None => true,
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};
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match version_match {
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true => Ok(self.migrations.push(Box::new(migration))),
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false => Err(Error::CannotAddMigration),
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}
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}
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/// Performs migration to destination.
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pub fn execute<D>(&self, db_iter: D, version: u32, destination: &mut Destination) -> Result<(), Error> where
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D: Iterator<Item = (Vec<u8>, Vec<u8>)> {
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let migrations = try!(self.migrations_from(version).ok_or(Error::MigrationImpossible));
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let mut batch: BTreeMap<Vec<u8>, Vec<u8>> = BTreeMap::new();
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for keypair in db_iter {
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let migrated = migrations.iter().fold(Some(keypair), |migrated, migration| {
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migrated.and_then(|(key, value)| migration.simple_migrate(key, value))
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});
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if let Some((key, value)) = migrated {
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batch.insert(key, value);
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}
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if batch.len() == self.config.batch_size {
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try!(destination.commit(batch));
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batch = BTreeMap::new();
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}
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}
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try!(destination.commit(batch));
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Ok(())
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}
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/// Returns true if migration is needed.
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pub fn is_needed(&self, version: u32) -> bool {
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match self.migrations.last() {
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Some(last) => version < last.version(),
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None => false,
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}
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}
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fn migrations_from(&self, version: u32) -> Option<&[Box<Migration>]> {
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// index of the first required migration
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let position = self.migrations.iter().position(|m| m.version() == version + 1);
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position.map(|p| &self.migrations[p..])
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}
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}
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