diff options
Diffstat (limited to 'node_modules/mysql2/lib/packet_parser.js')
| -rw-r--r-- | node_modules/mysql2/lib/packet_parser.js | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/node_modules/mysql2/lib/packet_parser.js b/node_modules/mysql2/lib/packet_parser.js new file mode 100644 index 0000000..1899e56 --- /dev/null +++ b/node_modules/mysql2/lib/packet_parser.js @@ -0,0 +1,195 @@ +'use strict'; + +const Packet = require('./packets/packet.js'); + +const MAX_PACKET_LENGTH = 16777215; + +function readPacketLength(b, off) { + const b0 = b[off]; + const b1 = b[off + 1]; + const b2 = b[off + 2]; + if (b1 + b2 === 0) { + return b0; + } + return b0 + (b1 << 8) + (b2 << 16); +} + +class PacketParser { + constructor(onPacket, packetHeaderLength) { + // 4 for normal packets, 7 for comprssed protocol packets + if (typeof packetHeaderLength === 'undefined') { + packetHeaderLength = 4; + } + // array of last payload chunks + // only used when current payload is not complete + this.buffer = []; + // total length of chunks on buffer + this.bufferLength = 0; + this.packetHeaderLength = packetHeaderLength; + // incomplete header state: number of header bytes received + this.headerLen = 0; + // expected payload length + this.length = 0; + this.largePacketParts = []; + this.firstPacketSequenceId = 0; + this.onPacket = onPacket; + this.execute = PacketParser.prototype.executeStart; + this._flushLargePacket = + packetHeaderLength === 7 + ? this._flushLargePacket7 + : this._flushLargePacket4; + } + + _flushLargePacket4() { + const numPackets = this.largePacketParts.length; + this.largePacketParts.unshift(Buffer.from([0, 0, 0, 0])); // insert header + const body = Buffer.concat(this.largePacketParts); + const packet = new Packet(this.firstPacketSequenceId, body, 0, body.length); + this.largePacketParts.length = 0; + packet.numPackets = numPackets; + this.onPacket(packet); + } + + _flushLargePacket7() { + const numPackets = this.largePacketParts.length; + this.largePacketParts.unshift(Buffer.from([0, 0, 0, 0, 0, 0, 0])); // insert header + const body = Buffer.concat(this.largePacketParts); + this.largePacketParts.length = 0; + const packet = new Packet(this.firstPacketSequenceId, body, 0, body.length); + packet.numPackets = numPackets; + this.onPacket(packet); + } + + executeStart(chunk) { + let start = 0; + const end = chunk.length; + while (end - start >= 3) { + this.length = readPacketLength(chunk, start); + if (end - start >= this.length + this.packetHeaderLength) { + // at least one full packet + const sequenceId = chunk[start + 3]; + if ( + this.length < MAX_PACKET_LENGTH && + this.largePacketParts.length === 0 + ) { + this.onPacket( + new Packet( + sequenceId, + chunk, + start, + start + this.packetHeaderLength + this.length + ) + ); + } else { + // first large packet - remember it's id + if (this.largePacketParts.length === 0) { + this.firstPacketSequenceId = sequenceId; + } + this.largePacketParts.push( + chunk.slice( + start + this.packetHeaderLength, + start + this.packetHeaderLength + this.length + ) + ); + if (this.length < MAX_PACKET_LENGTH) { + this._flushLargePacket(); + } + } + start += this.packetHeaderLength + this.length; + } else { + // payload is incomplete + this.buffer = [chunk.slice(start + 3, end)]; + this.bufferLength = end - start - 3; + this.execute = PacketParser.prototype.executePayload; + return; + } + } + if (end - start > 0) { + // there is start of length header, but it's not full 3 bytes + this.headerLen = end - start; // 1 or 2 bytes + this.length = chunk[start]; + if (this.headerLen === 2) { + this.length = chunk[start] + (chunk[start + 1] << 8); + this.execute = PacketParser.prototype.executeHeader3; + } else { + this.execute = PacketParser.prototype.executeHeader2; + } + } + } + + executePayload(chunk) { + let start = 0; + const end = chunk.length; + const remainingPayload = + this.length - this.bufferLength + this.packetHeaderLength - 3; + if (end - start >= remainingPayload) { + // last chunk for payload + const payload = Buffer.allocUnsafe(this.length + this.packetHeaderLength); + let offset = 3; + for (let i = 0; i < this.buffer.length; ++i) { + this.buffer[i].copy(payload, offset); + offset += this.buffer[i].length; + } + chunk.copy(payload, offset, start, start + remainingPayload); + const sequenceId = payload[3]; + if ( + this.length < MAX_PACKET_LENGTH && + this.largePacketParts.length === 0 + ) { + this.onPacket( + new Packet( + sequenceId, + payload, + 0, + this.length + this.packetHeaderLength + ) + ); + } else { + // first large packet - remember it's id + if (this.largePacketParts.length === 0) { + this.firstPacketSequenceId = sequenceId; + } + this.largePacketParts.push( + payload.slice( + this.packetHeaderLength, + this.packetHeaderLength + this.length + ) + ); + if (this.length < MAX_PACKET_LENGTH) { + this._flushLargePacket(); + } + } + this.buffer = []; + this.bufferLength = 0; + this.execute = PacketParser.prototype.executeStart; + start += remainingPayload; + if (end - start > 0) { + return this.execute(chunk.slice(start, end)); + } + } else { + this.buffer.push(chunk); + this.bufferLength += chunk.length; + } + return null; + } + + executeHeader2(chunk) { + this.length += chunk[0] << 8; + if (chunk.length > 1) { + this.length += chunk[1] << 16; + this.execute = PacketParser.prototype.executePayload; + return this.executePayload(chunk.slice(2)); + } + this.execute = PacketParser.prototype.executeHeader3; + + return null; + } + + executeHeader3(chunk) { + this.length += chunk[0] << 16; + this.execute = PacketParser.prototype.executePayload; + return this.executePayload(chunk.slice(1)); + } +} + +module.exports = PacketParser; |