fcoin/lib/bcoin/chaindb.js
Christopher Jeffrey e912f78814 async chain.
2016-02-16 03:03:11 -08:00

503 lines
11 KiB
JavaScript

/**
* chaindb.js - blockchain data management for bcoin
* Copyright (c) 2014-2015, Fedor Indutny (MIT License)
* https://github.com/indutny/bcoin
*/
var inherits = require('inherits');
var EventEmitter = require('events').EventEmitter;
var bcoin = require('../bcoin');
var bn = require('bn.js');
var constants = bcoin.protocol.constants;
var network = bcoin.protocol.network;
var utils = bcoin.utils;
var assert = utils.assert;
var fs = bcoin.fs;
var BLOCK_SIZE = bcoin.chainblock.BLOCK_SIZE;
/**
* ChainDB
*/
function ChainDB(chain, options) {
if (!(this instanceof ChainDB))
return new ChainDB(chain, options);
if (!options)
options = {};
this.options = options;
this.chain = chain;
this.file = options.file;
if (!this.file)
this.file = process.env.HOME + '/bcoin-chain-' + network.type + '.db';
this._queue = [];
this._cache = {};
this._bufferPool = { used: {} };
this._nullBlock = new Buffer(BLOCK_SIZE);
this._nullBlock.fill(0);
this.tip = -1;
this.size = 0;
this.fd = null;
// Need to cache up to the retarget interval
// if we're going to be checking the damn
// target all the time.
if (network.powAllowMinDifficultyBlocks)
this._cacheWindow = network.powDiffInterval + 1;
else
this._cacheWindow = network.block.majorityWindow + 1;
this._init();
}
ChainDB.prototype._init = function _init() {
if (!bcoin.fs) {
utils.debug('`fs` module not available. Falling back to ramdisk.');
this.ramdisk = new bcoin.ramdisk(40 * 1024 * 1024);
return;
}
if (+process.env.BCOIN_FRESH === 1) {
try {
fs.unlinkSync(this.file);
} catch (e) {
;
}
}
if (!this.exists())
fs.writeFileSync(this.file, new Buffer([]));
this.size = this.getSize();
if (this.size % BLOCK_SIZE !== 0) {
utils.debug('Blockchain is at an odd length. Truncating.');
fs.truncateSync(this.file, this.size - (this.size % BLOCK_SIZE));
this.size = this.getSize();
assert(this.size % BLOCK_SIZE === 0);
}
this.fd = fs.openSync(this.file, 'r+');
};
ChainDB.prototype._malloc = function(size) {
if (!this._bufferPool[size])
this._bufferPool[size] = new Buffer(size);
if (this._bufferPool.used[size] === this._bufferPool[size])
return new Buffer(size);
this._bufferPool.used[size] = this._bufferPool[size];
return this._bufferPool[size];
};
ChainDB.prototype._free = function(buf) {
if (this._bufferPool.used[buf.length] === buf) {
assert(this._bufferPool[buf.length] === buf);
delete this._bufferPool.used[buf.length];
}
};
ChainDB.prototype.exists = function exists() {
if (!bcoin.fs)
return true;
try {
fs.statSync(this.file);
return true;
} catch (e) {
return false;
}
};
ChainDB.prototype.getSize = function getSize() {
if (!bcoin.fs)
return this.ramdisk.size;
try {
return fs.statSync(this.file).size;
} catch (e) {
return 0;
}
};
ChainDB.prototype.count = function count() {
var len = this.size / BLOCK_SIZE;
assert(len % 1 === 0);
return len;
};
ChainDB.prototype.cache = function cache(entry) {
if (entry.height > this.tip) {
this.tip = entry.height;
delete this._cache[entry.height - this._cacheWindow];
this._cache[entry.height] = entry;
assert(Object.keys(this._cache).length <= this._cacheWindow);
}
};
ChainDB.prototype.get = function get(height) {
return this.getSync(height);
};
ChainDB.prototype.getSync = function getSync(height) {
var data, entry;
if (this._cache[height])
return this._cache[height];
if (this._queue[height])
return this._queue[height];
if (height < 0 || height == null)
return;
if ((height + 1) * BLOCK_SIZE > this.size)
return;
data = this._readSync(BLOCK_SIZE, height * BLOCK_SIZE);
if (!data)
return;
// Ignore if it is a null block.
if (utils.read32(data, 0) === 0)
return;
entry = bcoin.chainblock.fromRaw(this.chain, height, data);
// Cache the past 1001 blocks in memory
// (necessary for isSuperMajority)
this.cache(entry);
return entry;
};
ChainDB.prototype.getAsync = function getAsync(height, callback) {
var self = this;
callback = utils.asyncify(callback);
if (this._cache[height])
return callback(null, this._cache[height]);
if (this._queue[height])
return callback(null, this._queue[height]);
if (height < 0 || height == null)
return callback();
if ((height + 1) * BLOCK_SIZE > this.size)
return callback();
return this._readAsync(BLOCK_SIZE, height * BLOCK_SIZE, function(err, data) {
var entry;
// We can't ensure the integrity of
// the chain if we get an error.
// Just throw.
if (err)
throw err;
if (!data)
return callback();
// Ignore if it is a null block.
if (utils.read32(data, 0) === 0)
return callback();
entry = bcoin.chainblock.fromRaw(self.chain, height, data);
// Cache the past 1001 blocks in memory
// (necessary for isSuperMajority)
self.cache(entry);
return callback(null, entry);
});
};
ChainDB.prototype.save = function save(entry, callback) {
return this.saveAsync(entry, callback);
};
ChainDB.prototype.saveSync = function saveSync(entry) {
var self = this;
var raw, offset;
// Cache the past 1001 blocks in memory
// (necessary for isSuperMajority)
this.cache(entry);
raw = entry.toRaw();
offset = entry.height * BLOCK_SIZE;
return this._writeSync(raw, offset);
};
ChainDB.prototype.saveAsync = function saveAsync(entry, callback) {
var self = this;
var raw, offset;
callback = utils.asyncify(callback);
// Cache the past 1001 blocks in memory
// (necessary for isSuperMajority)
this.cache(entry);
// Something is already writing. Cancel it
// and synchronously write the data after
// it cancels.
if (this._queue[entry.height]) {
this._queue[entry.height] = entry;
return callback();
}
// Speed up writes by doing them asynchronously
// and keeping the data to be written in memory.
this._queue[entry.height] = entry;
// Write asynchronously to the db.
raw = entry.toRaw();
offset = entry.height * BLOCK_SIZE;
return this._writeAsync(raw, offset, function(err, success) {
// We can't ensure the integrity of
// the chain if we get an error.
// Just throw.
if (err)
throw err;
var item = self._queue[entry.height];
// Something tried to write here but couldn't.
// Synchronously write it and get it over with.
try {
if (item && item !== entry)
success = self._writeSync(item.toRaw(), offset);
} catch (e) {
err = e;
}
delete self._queue[entry.height];
return callback(null, success);
});
};
ChainDB.prototype.remove = function remove(height) {
assert(height >= 0);
// Potential race condition here. Not sure how
// to handle this.
if (this._queue[height]) {
utils.debug('Warning: write job in progress.');
delete this._queue[height];
}
this._writeSync(this._nullBlock, height * BLOCK_SIZE);
delete this._cache[height];
// If we deleted several blocks at the end, go back
// to the last non-null block and truncate the file
// beyond that point.
if ((height + 1) * BLOCK_SIZE === this.size) {
while (this.isNull(height))
height--;
assert(height >= 0);
this.truncate(height);
}
return true;
};
ChainDB.prototype.truncate = function truncate(height) {
this.size = (height + 1) * BLOCK_SIZE;
this.tip = height;
if (!bcoin.fs) {
this.ramdisk.truncate(this.size);
return;
}
fs.ftruncateSync(this.fd, this.size);
};
ChainDB.prototype.isNull = function isNull(height) {
var data = this._readSync(4, height * BLOCK_SIZE);
if (!data)
return false;
return utils.read32(data, 0) === 0;
};
ChainDB.prototype.has = function has(height) {
var data;
if (this._queue[height] || this._cache[height])
return true;
if (height < 0 || height == null)
return false;
if ((height + 1) * BLOCK_SIZE > this.size)
return false;
data = this._readSync(4, height * BLOCK_SIZE);
if (!data)
return false;
return utils.read32(data, 0) !== 0;
};
ChainDB.prototype._readSync = function _readSync(size, offset) {
var index = 0;
var data, bytes;
if (offset < 0 || offset == null)
return;
if (!bcoin.fs)
return this.ramdisk.read(size, offset);
data = this._malloc(size);
try {
while (bytes = fs.readSync(this.fd, data, index, size, offset)) {
index += bytes;
size -= bytes;
offset += bytes;
if (index === data.length) {
this._free(data);
return data;
}
}
} catch (e) {
this._free(data);
throw e;
}
this._free(data);
throw new Error('_readSync() failed.');
};
ChainDB.prototype._readAsync = function _readAsync(size, offset, callback) {
var self = this;
var index = 0;
var data, bytes;
callback = utils.asyncify(callback);
if (offset < 0 || offset == null)
return callback();
if (!bcoin.fs)
return callback(null, this.ramdisk.read(size, offset));
data = this._malloc(size);
(function next() {
fs.read(self.fd, data, index, size, offset, function(err, bytes) {
if (err) {
self._free(data);
return callback(err);
}
index += bytes;
size -= bytes;
offset += bytes;
if (index === data.length) {
self._free(data);
return callback(null, data);
}
next();
});
})();
};
ChainDB.prototype._writeSync = function _writeSync(data, offset) {
var size = data.length;
var added = Math.max(0, (offset + data.length) - this.size);
var index = 0;
var bytes;
if (offset < 0 || offset == null)
return false;
if (!bcoin.fs) {
this.size += added;
this.ramdisk.write(data, offset);
return;
}
try {
while (bytes = fs.writeSync(this.fd, data, index, size, offset)) {
index += bytes;
size -= bytes;
offset += bytes;
if (index === data.length) {
this.size += added;
return true;
}
}
} catch (e) {
throw e;
}
throw new Error('_writeSync() failed.');
};
ChainDB.prototype._writeAsync = function _writeAsync(data, offset, callback) {
var self = this;
var added = Math.max(0, (offset + data.length) - this.size);
var size = data.length;
var index = 0;
callback = utils.asyncify(callback);
if (offset < 0 || offset == null)
return callback(null, false);
if (!bcoin.fs) {
this.size += added;
this.ramdisk.write(data, offset);
return callback(null, true);
}
this.size += added;
(function next() {
fs.write(self.fd, data, index, size, offset, function(err, bytes) {
if (err) {
self.size -= (added - index);
return callback(err);
}
index += bytes;
size -= bytes;
offset += bytes;
if (index === data.length)
return callback(null, true);
next();
});
})();
};
/**
* Expose
*/
module.exports = ChainDB;