136 lines
3.5 KiB
Rust
136 lines
3.5 KiB
Rust
// Copyright 2015-2017 Parity Technologies (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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//! Ethcore database trait
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use std::cell::RefCell;
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pub type IteratorHandle = u32;
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pub const DEFAULT_CACHE_LEN: usize = 12288;
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#[derive(Binary)]
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pub struct KeyValue {
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pub key: Vec<u8>,
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pub value: Vec<u8>,
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}
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#[derive(Debug, Binary)]
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pub enum Error {
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AlreadyOpen,
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IsClosed,
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RocksDb(String),
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TransactionUnknown,
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IteratorUnknown,
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UncommitedTransactions,
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}
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impl From<String> for Error {
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fn from(s: String) -> Error {
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Error::RocksDb(s)
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}
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}
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/// Database configuration
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#[derive(Binary)]
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pub struct DatabaseConfig {
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/// Optional prefix size in bytes. Allows lookup by partial key.
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pub prefix_size: Option<usize>,
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/// write cache length
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pub cache: usize,
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}
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impl Default for DatabaseConfig {
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fn default() -> DatabaseConfig {
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DatabaseConfig {
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prefix_size: None,
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cache: DEFAULT_CACHE_LEN,
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}
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}
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}
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impl DatabaseConfig {
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fn with_prefix(prefix: usize) -> DatabaseConfig {
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DatabaseConfig {
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prefix_size: Some(prefix),
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cache: DEFAULT_CACHE_LEN,
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}
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}
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}
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pub trait DatabaseService : Sized {
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/// Opens database in the specified path
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fn open(&self, config: DatabaseConfig, path: String) -> Result<(), Error>;
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/// Opens database in the specified path with the default config
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fn open_default(&self, path: String) -> Result<(), Error>;
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/// Closes database
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fn close(&self) -> Result<(), Error>;
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/// Insert a key-value pair in the transaction. Any existing value value will be overwritten.
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fn put(&self, key: &[u8], value: &[u8]) -> Result<(), Error>;
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/// Delete value by key.
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fn delete(&self, key: &[u8]) -> Result<(), Error>;
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/// Get value by key.
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fn get(&self, key: &[u8]) -> Result<Option<Vec<u8>>, Error>;
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/// Get value by partial key. Prefix size should match configured prefix size.
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fn get_by_prefix(&self, prefix: &[u8]) -> Result<Option<Vec<u8>>, Error>;
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/// Check if there is anything in the database.
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fn is_empty(&self) -> Result<bool, Error>;
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/// Get handle to iterate through keys
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fn iter(&self) -> Result<IteratorHandle, Error>;
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/// Next key-value for the the given iterator
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fn iter_next(&self, iterator: IteratorHandle) -> Option<KeyValue>;
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/// Dispose iteration that is no longer needed
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fn dispose_iter(&self, handle: IteratorHandle) -> Result<(), Error>;
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/// Write client transaction
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fn write(&self, transaction: DBTransaction) -> Result<(), Error>;
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}
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#[derive(Binary)]
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pub struct DBTransaction {
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pub writes: RefCell<Vec<KeyValue>>,
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pub removes: RefCell<Vec<Vec<u8>>>,
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}
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impl DBTransaction {
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pub fn new() -> DBTransaction {
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DBTransaction {
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writes: RefCell::new(Vec::new()),
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removes: RefCell::new(Vec::new()),
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}
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}
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pub fn put(&self, key: &[u8], value: &[u8]) {
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let mut brw = self.writes.borrow_mut();
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brw.push(KeyValue { key: key.to_vec(), value: value.to_vec() });
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}
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pub fn delete(&self, key: &[u8]) {
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let mut brw = self.removes.borrow_mut();
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brw.push(key.to_vec());
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}
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}
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