| 1 | package net.spy.memcached.protocol.binary; |
| 2 | |
| 3 | import java.io.IOException; |
| 4 | import java.nio.ByteBuffer; |
| 5 | import java.nio.ByteOrder; |
| 6 | import java.util.concurrent.atomic.AtomicInteger; |
| 7 | |
| 8 | import net.spy.memcached.CASResponse; |
| 9 | import net.spy.memcached.KeyUtil; |
| 10 | import net.spy.memcached.ops.CASOperationStatus; |
| 11 | import net.spy.memcached.ops.OperationCallback; |
| 12 | import net.spy.memcached.ops.OperationErrorType; |
| 13 | import net.spy.memcached.ops.OperationState; |
| 14 | import net.spy.memcached.ops.OperationStatus; |
| 15 | import net.spy.memcached.protocol.BaseOperationImpl; |
| 16 | |
| 17 | /** |
| 18 | * Base class for binary operations. |
| 19 | */ |
| 20 | abstract class OperationImpl extends BaseOperationImpl { |
| 21 | |
| 22 | protected static final byte REQ_MAGIC = (byte)0x80; |
| 23 | protected static final byte RES_MAGIC = (byte)0x81; |
| 24 | protected static final int MIN_RECV_PACKET=24; |
| 25 | |
| 26 | /** |
| 27 | * Error code for items that were not found. |
| 28 | */ |
| 29 | protected static final int ERR_NOT_FOUND = 1; |
| 30 | protected static final int ERR_EXISTS = 2; |
| 31 | protected static final int ERR_EINVAL = 4; |
| 32 | protected static final int ERR_NOT_STORED = 5; |
| 33 | |
| 34 | protected static final OperationStatus NOT_FOUND_STATUS = |
| 35 | new CASOperationStatus(false, "Not Found", CASResponse.NOT_FOUND); |
| 36 | protected static final OperationStatus EXISTS_STATUS = |
| 37 | new CASOperationStatus(false, "Object exists", CASResponse.EXISTS); |
| 38 | protected static final OperationStatus NOT_STORED_STATUS = |
| 39 | new CASOperationStatus(false, "Not Stored", CASResponse.NOT_FOUND); |
| 40 | |
| 41 | protected static final byte[] EMPTY_BYTES = new byte[0]; |
| 42 | |
| 43 | protected static final OperationStatus STATUS_OK = |
| 44 | new CASOperationStatus(true, "OK", CASResponse.OK); |
| 45 | |
| 46 | private static final AtomicInteger seqNumber=new AtomicInteger(0); |
| 47 | |
| 48 | // request header fields |
| 49 | private final int cmd; |
| 50 | protected final int opaque; |
| 51 | |
| 52 | private final byte[] header=new byte[MIN_RECV_PACKET]; |
| 53 | private int headerOffset=0; |
| 54 | private byte[] payload=null; |
| 55 | |
| 56 | // Response header fields |
| 57 | protected int keyLen; |
| 58 | protected int responseCmd; |
| 59 | protected int errorCode; |
| 60 | protected int responseOpaque; |
| 61 | protected long responseCas; |
| 62 | |
| 63 | private int payloadOffset=0; |
| 64 | |
| 65 | /** |
| 66 | * Construct with opaque. |
| 67 | * |
| 68 | * @param o the opaque value. |
| 69 | * @param cb |
| 70 | */ |
| 71 | protected OperationImpl(int c, int o, OperationCallback cb) { |
| 72 | super(); |
| 73 | cmd=c; |
| 74 | opaque=o; |
| 75 | setCallback(cb); |
| 76 | } |
| 77 | |
| 78 | protected void resetInput() { |
| 79 | payload=null; |
| 80 | payloadOffset=0; |
| 81 | headerOffset=0; |
| 82 | } |
| 83 | |
| 84 | // Base response packet format: |
| 85 | // 0 1 2 3 4 5 6 7 8 9 10 11 |
| 86 | // # magic, opcode, keylen, extralen, datatype, status, bodylen, |
| 87 | // 12,3,4,5 16 |
| 88 | // opaque, cas |
| 89 | // RES_PKT_FMT=">BBHBBHIIQ" |
| 90 | |
| 91 | @Override |
| 92 | public void readFromBuffer(ByteBuffer b) throws IOException { |
| 93 | // First process headers if we haven't completed them yet |
| 94 | if(headerOffset < MIN_RECV_PACKET) { |
| 95 | int toRead=MIN_RECV_PACKET - headerOffset; |
| 96 | int available=b.remaining(); |
| 97 | toRead=Math.min(toRead, available); |
| 98 | getLogger().debug("Reading %d header bytes", toRead); |
| 99 | b.get(header, headerOffset, toRead); |
| 100 | headerOffset+=toRead; |
| 101 | |
| 102 | // We've completed reading the header. Prepare body read. |
| 103 | if(headerOffset == MIN_RECV_PACKET) { |
| 104 | int magic=header[0]; |
| 105 | assert magic == RES_MAGIC : "Invalid magic: " + magic; |
| 106 | responseCmd=header[1]; |
| 107 | assert cmd == -1 || responseCmd == cmd |
| 108 | : "Unexpected response command value"; |
| 109 | keyLen=decodeShort(header, 2); |
| 110 | // TODO: Examine extralen and datatype |
| 111 | errorCode=decodeShort(header, 6); |
| 112 | int bytesToRead=decodeInt(header, 8); |
| 113 | payload=new byte[bytesToRead]; |
| 114 | responseOpaque=decodeInt(header, 12); |
| 115 | responseCas=decodeLong(header, 16); |
| 116 | assert opaqueIsValid() : "Opaque is not valid"; |
| 117 | } |
| 118 | } |
| 119 | |
| 120 | // Now process the payload if we can. |
| 121 | if(headerOffset >= MIN_RECV_PACKET && payload == null) { |
| 122 | finishedPayload(EMPTY_BYTES); |
| 123 | } else if(payload != null) { |
| 124 | int toRead=payload.length - payloadOffset; |
| 125 | int available=b.remaining(); |
| 126 | toRead=Math.min(toRead, available); |
| 127 | getLogger().debug("Reading %d payload bytes", toRead); |
| 128 | b.get(payload, payloadOffset, toRead); |
| 129 | payloadOffset+=toRead; |
| 130 | |
| 131 | // Have we read it all? |
| 132 | if(payloadOffset == payload.length) { |
| 133 | finishedPayload(payload); |
| 134 | } |
| 135 | } else { |
| 136 | // Haven't read enough to make up a payload. Must read more. |
| 137 | getLogger().debug("Only read %d of the %d needed to fill a header", |
| 138 | headerOffset, MIN_RECV_PACKET); |
| 139 | } |
| 140 | |
| 141 | } |
| 142 | |
| 143 | protected void finishedPayload(byte[] pl) throws IOException { |
| 144 | if(errorCode != 0) { |
| 145 | OperationStatus status=getStatusForErrorCode(errorCode, pl); |
| 146 | if(status == null) { |
| 147 | handleError(OperationErrorType.SERVER, new String(pl)); |
| 148 | } else { |
| 149 | getCallback().receivedStatus(status); |
| 150 | transitionState(OperationState.COMPLETE); |
| 151 | } |
| 152 | } else { |
| 153 | decodePayload(pl); |
| 154 | transitionState(OperationState.COMPLETE); |
| 155 | } |
| 156 | } |
| 157 | |
| 158 | /** |
| 159 | * Get the OperationStatus object for the given error code. |
| 160 | * |
| 161 | * @param errCode the error code |
| 162 | * @return the status to return, or null if this is an exceptional case |
| 163 | */ |
| 164 | protected OperationStatus getStatusForErrorCode(int errCode, byte[] errPl) { |
| 165 | return null; |
| 166 | } |
| 167 | |
| 168 | /** |
| 169 | * Decode the given payload for this command. |
| 170 | * |
| 171 | * @param pl the payload. |
| 172 | */ |
| 173 | protected void decodePayload(byte[] pl) { |
| 174 | assert pl.length == 0 : "Payload has bytes, but decode isn't overridden"; |
| 175 | getCallback().receivedStatus(STATUS_OK); |
| 176 | } |
| 177 | |
| 178 | /** |
| 179 | * Validate an opaque value from the header. |
| 180 | * This may be overridden from a subclass where the opaque isn't expected |
| 181 | * to always be the same as the request opaque. |
| 182 | */ |
| 183 | protected boolean opaqueIsValid() { |
| 184 | if(responseOpaque != opaque) { |
| 185 | getLogger().warn("Expected opaque: %d, got opaque: %d\n", |
| 186 | responseOpaque, opaque); |
| 187 | } |
| 188 | return responseOpaque == opaque; |
| 189 | } |
| 190 | |
| 191 | static int decodeShort(byte[] data, int i) { |
| 192 | return (data[i] & 0xff) << 8 |
| 193 | | (data[i+1] & 0xff); |
| 194 | } |
| 195 | |
| 196 | static int decodeInt(byte[] data, int i) { |
| 197 | return (data[i] & 0xff) << 24 |
| 198 | | (data[i+1] & 0xff) << 16 |
| 199 | | (data[i+2] & 0xff) << 8 |
| 200 | | (data[i+3] & 0xff); |
| 201 | } |
| 202 | |
| 203 | static long decodeUnsignedInt(byte[] data, int i) { |
| 204 | return ((long)(data[i] & 0xff) << 24) |
| 205 | | ((data[i+1] & 0xff) << 16) |
| 206 | | ((data[i+2] & 0xff) << 8) |
| 207 | | (data[i+3] & 0xff); |
| 208 | } |
| 209 | |
| 210 | static long decodeLong(byte[] data, int i) { |
| 211 | return(data[i ] & 0xff) << 56 |
| 212 | | (data[i+1] & 0xff) << 48 |
| 213 | | (data[i+2] & 0xff) << 40 |
| 214 | | (data[i+3] & 0xff) << 32 |
| 215 | | (data[i+4] & 0xff) << 24 |
| 216 | | (data[i+5] & 0xff) << 16 |
| 217 | | (data[i+6] & 0xff) << 8 |
| 218 | | (data[i+7] & 0xff); |
| 219 | } |
| 220 | |
| 221 | /** |
| 222 | * Prepare a send buffer. |
| 223 | * |
| 224 | * @param key the key (for keyed ops) |
| 225 | * @param cas the cas value |
| 226 | * @param val the data payload |
| 227 | * @param extraHeaders any additional headers that need to be sent |
| 228 | */ |
| 229 | protected void prepareBuffer(String key, long cas, byte[] val, |
| 230 | Object... extraHeaders) { |
| 231 | int extraLen=0; |
| 232 | for(Object o : extraHeaders) { |
| 233 | if(o instanceof Integer) { |
| 234 | extraLen += 4; |
| 235 | } else if(o instanceof byte[]) { |
| 236 | extraLen += ((byte[])o).length; |
| 237 | } else if(o instanceof Long) { |
| 238 | extraLen += 8; |
| 239 | } else { |
| 240 | assert false : "Unhandled extra header type: " + o.getClass(); |
| 241 | } |
| 242 | } |
| 243 | final byte[] keyBytes=KeyUtil.getKeyBytes(key); |
| 244 | int bufSize=MIN_RECV_PACKET + keyBytes.length + val.length; |
| 245 | |
| 246 | // # magic, opcode, keylen, extralen, datatype, [reserved], |
| 247 | // bodylen, opaque, cas |
| 248 | // REQ_PKT_FMT=">BBHBBxxIIQ" |
| 249 | |
| 250 | // set up the initial header stuff |
| 251 | ByteBuffer bb=ByteBuffer.allocate(bufSize + extraLen); |
| 252 | assert bb.order() == ByteOrder.BIG_ENDIAN; |
| 253 | bb.put(REQ_MAGIC); |
| 254 | bb.put((byte)cmd); |
| 255 | bb.putShort((short)keyBytes.length); |
| 256 | bb.put((byte)extraLen); |
| 257 | bb.put((byte)0); // data type |
| 258 | bb.putShort((short)0); // reserved |
| 259 | bb.putInt(keyBytes.length + val.length + extraLen); |
| 260 | bb.putInt(opaque); |
| 261 | bb.putLong(cas); |
| 262 | |
| 263 | // Add the extra headers. |
| 264 | for(Object o : extraHeaders) { |
| 265 | if(o instanceof Integer) { |
| 266 | bb.putInt((Integer)o); |
| 267 | } else if(o instanceof byte[]) { |
| 268 | bb.put((byte[])o); |
| 269 | } else if(o instanceof Long) { |
| 270 | bb.putLong((Long)o); |
| 271 | } else { |
| 272 | assert false : "Unhandled extra header type: " + o.getClass(); |
| 273 | } |
| 274 | } |
| 275 | |
| 276 | // Add the normal stuff |
| 277 | bb.put(keyBytes); |
| 278 | bb.put(val); |
| 279 | |
| 280 | bb.flip(); |
| 281 | setBuffer(bb); |
| 282 | } |
| 283 | |
| 284 | /** |
| 285 | * Generate an opaque ID. |
| 286 | */ |
| 287 | static int generateOpaque() { |
| 288 | int rv = seqNumber.incrementAndGet(); |
| 289 | while(rv < 0) { |
| 290 | seqNumber.compareAndSet(rv, 0); |
| 291 | rv=seqNumber.incrementAndGet(); |
| 292 | } |
| 293 | return rv; |
| 294 | } |
| 295 | } |