std::shared_ptr<MyBuffer> ProtobufCodec::Encode(const CMessage& message)
{
std::shared_ptr<MyBuffer> ptrBuffer(new MyBuffer());
assert(0 == ptrBuffer->readableBytes());
const std::string& typeName = message.GetTypeName();
int32_t nameLen = static_cast<int32_t>(typeName.size() + 1);//'\0'
ptrBuffer->appendUint32(nameLen);
ptrBuffer->append(typeName.c_str(), nameLen);
//消息内容
size_t byte_size = message.ByteSize();
//ensure memory enough
ptrBuffer->ensureWritableBytes(byte_size);
//write data
message.SerializeWithCachedSizesToArray(reinterpret_cast<uint8_t*>(ptrBuffer->beginWrite()));
ptrBuffer->commit(byte_size);//move write index
//检验和
uint32_t checkSum = adler32(1, reinterpret_cast<const Bytef*>(ptrBuffer->peek()), ptrBuffer->readableBytes());
ptrBuffer->appendUint32(checkSum);
assert(ptrBuffer->readableBytes() == sizeof(nameLen)+nameLen + byte_size + sizeof(checkSum));
//消息长度
int32_t len = htonl(static_cast<int32_t>(ptrBuffer->readableBytes()));
ptrBuffer->prepend(&len, sizeof(len));
//delimiter
ptrBuffer->append("\r\n", 2);
return ptrBuffer;
}
void DB2Mon::getSnapshot(JNIEnv* env, sqlma *ma_ptr, Snapshot& snap)
{
int rc = 0; // return code
sqlca sqlca;
sqluint32 outputFormat;
// Determine the size of the snapshot
db2GetSnapshotSizeData getSnapshotSizeParam;
sqluint32 buffer_sz; // estimated buffer size
getSnapshotSizeParam.piSqlmaData = ma_ptr;
getSnapshotSizeParam.poBufferSize = &buffer_sz;
getSnapshotSizeParam.iVersion = SQLM_CURRENT_VERSION;
getSnapshotSizeParam.iNodeNumber = m_aggAllNodes ? SQLM_ALL_NODES : SQLM_CURRENT_NODE;
getSnapshotSizeParam.iSnapshotClass = SQLM_CLASS_DEFAULT;
rc = db2GetSnapshotSize(db2Version810, &getSnapshotSizeParam, &sqlca);
APICHECK(env, sqlca);
// Allocate memory to a buffer to hold snapshot monitor data.
// Add about 10k to make sure we avoid the reallocation below
buffer_sz = buffer_sz + SNAPSHOT_BUFFER_UNIT_SZ;
MemObj ptrBuffer(buffer_sz);
char * buffer_ptr = ptrBuffer.get();
sqlm_collected collected; // returned sqlm_collected structure
memset(&collected, '\0', sizeof(struct sqlm_collected));
db2GetSnapshotData getSnapshotParam;
getSnapshotParam.piSqlmaData = ma_ptr;
getSnapshotParam.poCollectedData = &collected;
getSnapshotParam.iBufferSize = buffer_sz;
getSnapshotParam.poBuffer = buffer_ptr;
getSnapshotParam.iVersion = SQLM_CURRENT_VERSION;
getSnapshotParam.iStoreResult = 0;
getSnapshotParam.iNodeNumber = m_aggAllNodes ? SQLM_ALL_NODES : SQLM_CURRENT_NODE;
getSnapshotParam.poOutputFormat = &outputFormat;
getSnapshotParam.iSnapshotClass = SQLM_CLASS_DEFAULT;
rc = db2GetSnapshot(db2Version810, &getSnapshotParam, &sqlca);
APICHECK(env, sqlca);
// If buffer was too small enlarge it and repeat until succeeded
while (sqlca.sqlcode == 1606)
{
buffer_sz = buffer_sz + SNAPSHOT_BUFFER_UNIT_SZ;
ptrBuffer.resize(buffer_sz);
buffer_ptr = ptrBuffer.get();
getSnapshotParam.iBufferSize = buffer_sz;
getSnapshotParam.poBuffer = buffer_ptr;
rc = db2GetSnapshot(db2Version810, &getSnapshotParam, &sqlca);
APICHECK(env, sqlca);
}
// Fill the snapshot object from the memory buffer
snap.initialize(env, buffer_ptr);
}