126 lines
3.0 KiB
JavaScript
126 lines
3.0 KiB
JavaScript
var assert = require('assert');
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var util = require('util');
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var EventEmitter = require('events').EventEmitter;
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var bcoin = require('../../bcoin');
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var utils = bcoin.utils;
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var constants = require('./constants');
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var readU32 = utils.readU32;
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var readU64 = utils.readU64;
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function Parser() {
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if (!(this instanceof Parser))
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return new Parser();
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EventEmitter.call(this);
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this.pending = [];
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this.pendingTotal = 0;
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this.waiting = 24;
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this.packet = null;
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}
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util.inherits(Parser, EventEmitter);
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module.exports = Parser;
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Parser.prototype.execute = function(data) {
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if (data) {
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this.pendingTotal += data.length;
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this.pending.push(data);
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}
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while (this.pendingTotal >= this.waiting) {
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// Concat chunks
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var chunk = new Array(this.waiting);
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for (var i = 0, off = 0, len = 0; off < chunk.length; i++) {
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len = utils.copy(this.pending[0], chunk, off);
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if (len === this.pending[0].length)
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this.pending.shift();
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else
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this.pending[0] = this.pending[0].slice(len);
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off += len;
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}
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assert.equal(off, chunk.length);
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// Slice buffers
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this.pendingTotal -= chunk.length;
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this.parse(chunk);
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}
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};
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Parser.prototype.parse = function parse(chunk) {
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if (this.packet === null) {
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this.packet = this.parseHeader(chunk);
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} else {
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this.packet.payload = chunk;
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if (readU32(utils.checksum(this.packet.payload)) !== this.packet.checksum)
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return this.emit('error', new Error('Invalid checksum'));
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this.packet.payload = this.parsePayload(this.packet.cmd,
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this.packet.payload);
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this.emit('packet', this.packet);
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this.waiting = 24;
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this.packet = null;
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}
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};
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Parser.prototype.parseHeader = function parseHeader(h) {
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var magic = readU32(h, 0);
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if (magic !== constants.magic) {
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return this.emit('error',
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new Error('Invalid magic value: ' + magic.toString(16)));
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}
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// Count length of the cmd
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for (var i = 0; h[i + 4] !== 0 && i < 12; i++);
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if (i === 12)
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return this.emit('error', new Error('Not NULL-terminated cmd'));
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var cmd = utils.stringify(h.slice(4, 4 + i));
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this.waiting = readU32(h, 16);
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return {
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cmd: cmd,
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length: this.waiting,
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checksum: readU32(h, 20)
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};
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};
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Parser.prototype.parsePayload = function parsePayload(cmd, p) {
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if (cmd === 'version')
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return this.parseVersion(p);
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else
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return p;
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};
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Parser.prototype.parseVersion = function parseVersion(p) {
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if (p.length < 85)
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return this.emit('error', new Error('version packet is too small'));
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var v = readU32(p, 0);
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if (v < constants.minVersion)
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return this.emit('error', new Error('version number is too small'));
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var services = readU64(p, 4);
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// Timestamp
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var ts = readU64(p, 12);
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// Nonce, very dramatic
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var nonce = { lo: readU32(p, 72), hi: readU32(p, 76) };
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// Start height
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var weight = readU32(p, 81);
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// Relay
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var relay = p.length >= 86 ? p[85] === 1 : true;
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return {
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v: v,
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services: services,
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ts: ts,
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nonce: nonce,
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weight: weight,
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relay: relay
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};
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};
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