server.cpp

实现内存数据库的源代码

	response = cli_not_found;
    } else { 
	return fetch(session, stmt);
    }
    pack4(response);
    return session->sock->write(&response, sizeof response);
}

bool dbServer::get_next(dbSession* session, int stmt_id)
{
    dbStatement* stmt = findStatement(session, stmt_id);
    int4 response;
    if (stmt == NULL || stmt->cursor == NULL) { 
	response = cli_bad_descriptor;
    } 
    else if (!((stmt->firstFetch && stmt->cursor->gotoFirst()) ||
	       (!stmt->firstFetch && stmt->cursor->gotoNext()))) 
    { 
	response = cli_not_found;
    } else { 
	return fetch(session, stmt);
    }
    pack4(response);
    return session->sock->write(&response, sizeof response);
}

bool dbServer::get_prev(dbSession* session, int stmt_id)
{
    dbStatement* stmt = findStatement(session, stmt_id);
    int4 response;
    if (stmt == NULL || stmt->cursor == NULL) { 
	response = cli_bad_descriptor;
    } 
    else if (!((stmt->firstFetch && stmt->cursor->gotoLast()) ||
	       (!stmt->firstFetch && stmt->cursor->gotoPrev()))) 
    { 
	response = cli_not_found;
    } else { 
	return fetch(session, stmt);
    }
    pack4(response);
    return session->sock->write(&response, sizeof response);
}


bool dbServer::fetch(dbSession* session, dbStatement* stmt)
{
    int4 response;
    dbColumnBinding* cb;
    
    stmt->firstFetch = false;
    if (stmt->cursor->isEmpty()) { 
	response = cli_not_found;
	pack4(response);
	return session->sock->write(&response, sizeof response);
    }
    int msg_size = sizeof(cli_oid_t) + 4;
    char* data = (char*)db->getRow(stmt->cursor->currId);
    for (cb = stmt->columns; cb != NULL; cb = cb->next) { 
	if (cb->cliType == cli_autoincrement) {
	    msg_size += 4;
	} else if (cb->cliType >= cli_array_of_oid) { 
	    msg_size += 4 + ((dbVarying*)(data + cb->fd->dbsOffs))->size
		            * sizeof_type[cb->cliType - cli_array_of_oid];
	} else if (cb->cliType >= cli_asciiz) { 
	    msg_size += 4 + ((dbVarying*)(data + cb->fd->dbsOffs))->size;
	} else { 
	    msg_size += sizeof_type[cb->cliType];
	}
    }
    if (stmt->buf_size < msg_size) { 
	delete[] stmt->buf;
	stmt->buf = new char[msg_size];
	stmt->buf_size = msg_size;
    }
    char* p = stmt->buf;
    p = pack4(p, msg_size);
    p = pack_oid(p, stmt->cursor->currId);

    for (cb = stmt->columns; cb != NULL; cb = cb->next) { 
	char* src = data + cb->fd->dbsOffs;
	switch (cb->fd->type) { 
	  case dbField::tpBool:
	  case dbField::tpInt1:
	    switch (sizeof_type[cb->cliType]) { 
	      case 1:
		*p++ = *src;
		break;
	      case 2:
		p = pack2(p, (int2)*(char*)src);
		break;
	      case 4:
		p = pack4(p, (int4)*(char*)src);
		break;
	      case 8:
		p = pack8(p, (int8)*(char*)src);
		break;
	      default:
		assert(false);
	    }
	    break;		
	  case dbField::tpInt2:
	    switch (sizeof_type[cb->cliType]) { 
	      case 1:
		*p++ = (char)*(int2*)src;
		break;
	      case 2:
		p = pack2(p, src);
		break;
	      case 4:
		p = pack4(p, (int4)*(int2*)src);
		break;
	      case 8:
		p = pack8(p, (int8)*(int2*)src);
		break;
	      default:
		assert(false);
	    }
	    break;
	  case dbField::tpInt4:
	    switch (sizeof_type[cb->cliType]) { 
	      case 1:
		*p++ = (char)*(int4*)src;
		break;
	      case 2:
		p = pack2(p, (int2)*(int4*)src);
		break;
	      case 4:
		p = pack4(p, src);
		break;
	      case 8:
		p = pack8(p, (int8)*(int4*)src);
		break;
	      default:
		assert(false);
	    }
	    break;
	  case dbField::tpInt8:
	    switch (sizeof_type[cb->cliType]) { 
	      case 1:
		*p++ = (char)*(int8*)src;
		break;
	      case 2:
		p = pack2(p, (int2)*(int8*)src);
		break;
	      case 4:
		p = pack4(p, (int4)*(int8*)src);
		break;
	      case 8:
		p = pack8(p, src);
		break;
	      default:
		assert(false);
	    }
	    break;
	  case dbField::tpReal4:
	    switch (cb->cliType) { 
	      case cli_real4:
		p = pack4(p, src);
		break;
	      case cli_real8:
		{
		    real8 temp = *(real4*)src;
		    p = pack8(p, (char*)&temp);
		}
		break;
	      default:
		assert(false);
	    }
	    break;
	  case dbField::tpReal8:
	    switch (cb->cliType) { 
	      case cli_real4:
		{
		    real4 temp = (real4)*(real8*)src;
		    p = pack4(p, (char*)&temp);
		}
		break;
	      case cli_real8:
		p = pack8(p, src);
		break;
	      default:
		assert(false);
	    }
	    break;
	  case dbField::tpString:
	    {
		dbVarying* v = (dbVarying*)src;
		p = pack4(p, v->size);
		memcpy(p, data + v->offs, v->size);
		p += v->size;
	    }
	    break;
	  case dbField::tpReference:
	    p = pack_oid(p, *(oid_t*)src);
	    break;
	  case dbField::tpArray:
	    {
		dbVarying* v = (dbVarying*)src;
		int n = v->size;
		p = pack4(p, n);
		src = data + v->offs;
		switch (sizeof_type[cb->cliType-cli_array_of_oid]) { 
		  case 2:
		    while (--n >= 0) { 
			p = pack2(p, src);
			src += 2;
		    }
		    break;
		  case 4:
		    while (--n >= 0) { 
			p = pack4(p, src);
			src += 4;
		    }
		    break;
		  case 8:
		    while (--n >= 0) { 
			p = pack8(p, src);
			src += 8;
		    }
		    break;
		  default:
		    memcpy(p, src, n);
		    p += n;
		}
		break;
	    }
	  default:
	    assert(false);
	}
    }
    assert(p - stmt->buf == msg_size);
    return session->sock->write(stmt->buf, msg_size);
}
    
bool dbServer::remove(dbSession* session, int stmt_id)
{
    dbStatement* stmt = findStatement(session, stmt_id);
    int4 response;
    if (stmt == NULL) { 
	response = cli_bad_descriptor;
    } else { 
	if (stmt->cursor->isEmpty()) { 
	    response = cli_not_found;
	} else { 
	    stmt->cursor->removeAllSelected();
	    response = cli_ok;
	}
    }
    pack4(response);
    return session->sock->write(&response, sizeof response);
}

bool dbServer::update(dbSession* session, int stmt_id, char* new_data)
{
    dbStatement* stmt = findStatement(session, stmt_id);
    dbColumnBinding* cb;
    int4 response;
    if (stmt == NULL) { 
	response = cli_bad_descriptor;
	pack4(response);
	return session->sock->write(&response, sizeof response);
    }
    if (stmt->cursor->isEmpty()) { 
	response = cli_not_found;
	pack4(response);
	return session->sock->write(&response, sizeof response);
    }
    char* old_data = stmt->buf + sizeof(cli_oid_t) + 4;
    for (cb = stmt->columns; cb != NULL; cb = cb->next) { 
	cb->ptr = new_data;
	if (cb->cliType >= cli_asciiz) { 
	    int new_len = unpack4(new_data);
	    int old_len = unpack4(old_data);
	    cb->len = new_len;
	    if (cb->fd->indexType & (HASHED|INDEXED) 
		&& memcmp(new_data, old_data, new_len+4) != 0)
	    {
		cb->fd->attr |= dbFieldDescriptor::Updated;
	    }
	    if (cb->cliType >= cli_array_of_oid) { 
		new_len *= sizeof_type[cb->cliType - cli_array_of_oid];
		old_len *= sizeof_type[cb->cliType - cli_array_of_oid];
	    }
	    new_data += 4 + new_len;
	    old_data += 4 + old_len;
	} else { 
	    int size = sizeof_type[cb->cliType];
	    if (cb->fd->indexType & (HASHED|INDEXED) 
		&& memcmp(new_data, old_data, size) != 0)
	    {
		cb->fd->attr |= dbFieldDescriptor::Updated;
	    }	    
	    new_data += size;
	    old_data += size;
	}
    }
    dbRecord* rec = db->getRow(stmt->cursor->currId);
    dbTableDescriptor* table = stmt->query.table;
    dbFieldDescriptor *first = table->columns, *fd = first;
    size_t offs = table->fixedSize;
    do { 
	if (fd->type == dbField::tpArray || fd->type == dbField::tpString) 
	{ 
	    int len = ((dbVarying*)((char*)rec + fd->dbsOffs))->size;
	    for (cb = stmt->columns; cb != NULL; cb = cb->next) { 
		if (cb->fd == fd) { 
		    len = cb->len;
		    break;
		}
	    }
	    offs = DOALIGN(offs, fd->components->alignment)
		+ len*fd->components->dbsSize;
	}
    } while ((fd = fd->next) != first);

    old_data = new char[rec->size];
    memcpy(old_data, rec, rec->size);

    for (cb = stmt->columns; cb != NULL; cb = cb->next) { 
	if (cb->fd->attr & dbFieldDescriptor::Updated) {	    
	    if (cb->fd->indexType & HASHED) { 
		dbHashTable::remove(db, cb->fd->hashTable, 
				    stmt->cursor->currId,
				    cb->fd->type, cb->fd->dbsSize, cb->fd->dbsOffs);
	    }
	    if (cb->fd->indexType & INDEXED) { 
		dbTtree::remove(db, cb->fd->tTree, stmt->cursor->currId, 
				cb->fd->type, cb->fd->dbsSize, cb->fd->comparator, cb->fd->dbsOffs);
	    }
	}
    }
    
    db->modified = true;
    new_data = (char*)db->putRow(stmt->cursor->currId, offs);    

    fd = first;
    offs = table->fixedSize;
    do { 
	if (fd->type == dbField::tpArray|| fd->type == dbField::tpString) 
	{ 
	    int len = ((dbVarying*)(old_data + fd->dbsOffs))->size;
	    offs = DOALIGN(offs, fd->components->alignment);
	    for (cb = stmt->columns; cb != NULL; cb = cb->next) { 
		if (cb->fd == fd) { 
		    len = cb->unpackArray(new_data, offs);
		    break;
		}
	    }
	    if (cb == NULL) { 
		memcpy(new_data + offs, 
		       old_data + ((dbVarying*)(old_data + fd->dbsOffs))->offs,
		       len*fd->components->dbsSize);
	    }
	    ((dbVarying*)(new_data + fd->dbsOffs))->size = len;
	    ((dbVarying*)(new_data + fd->dbsOffs))->offs = offs;
	    offs += len*fd->components->dbsSize;
	} else { 
	    
	    for (cb = stmt->columns; cb != NULL; cb = cb->next) { 
		if (cb->fd == fd) { 
		    cb->unpackScalar(new_data);
		    break;
		}
	    }
	    if (cb == NULL) { 
		memcpy(new_data + fd->dbsOffs, old_data + fd->dbsOffs, 
		       fd->dbsSize);
	    }
	}
    } while ((fd = fd->next) != first);

    delete[] old_data;

    for (cb = stmt->columns; cb != NULL; cb = cb->next) { 
	if (cb->fd->attr & dbFieldDescriptor::Updated) {	    
	    cb->fd->attr &= ~dbFieldDescriptor::Updated;
	    if (cb->fd->indexType & HASHED) { 
		dbHashTable::insert(db, cb->fd->hashTable, 
				    stmt->cursor->currId,
				    cb->fd->type, cb->fd->dbsSize, cb->fd->dbsOffs, 0);
	    }
	    if (cb->fd->indexType & INDEXED) { 
		dbTtree::insert(db, cb->fd->tTree, stmt->cursor->currId, 
				cb->fd->type, cb->fd->dbsSize, cb->fd->comparator, cb->fd->dbsOffs);
	    }
	}
    }
    response = cli_ok;
    pack4(response);
    return session->sock->write(&response, sizeof response);
}    


	    
char* dbServer::checkColumns(dbStatement* stmt, int n_columns, 
			     dbTableDescriptor* desc, char* data, 
			     int4& response)
{
    dbColumnBinding** cpp = &stmt->columns;
    response = cli_ok;
    while (--n_columns >= 0) {
	int cliType = *data++;
	char* columnName = data;
	dbSymbolTable::add(columnName, tkn_ident, true);    
	dbFieldDescriptor* fd = desc->find(columnName);
	data += strlen(data) + 1;
	if (fd != NULL) { 
	    if ((cliType == cli_oid 
		 && fd->type == dbField::tpReference)
		|| (cliType >= cli_bool && cliType <= cli_int8
		    && fd->type >= dbField::tpBool 
		    && fd->type <= dbField::tpInt8)
		|| (cliType >= cli_real4 && cliType <= cli_real8 
		    && fd->type >= dbField::tpReal4
		    && fd->type <= dbField::tpReal8)
		|| ((cliType == cli_asciiz || cliType == cli_pasciiz) 
		    && fd->type == dbField::tpString)
		|| (cliType == cli_array_of_oid && 
		    fd->type == dbField::tpArray && 
		    fd->components->type == dbField::tpReference)
		|| (cliType >= cli_array_of_bool
		    && fd->type  == dbField::tpArray
		    && cliType-cli_array_of_bool 
		    == fd->components->type-dbField::tpBool))
	    {
		dbColumnBinding* cb = new dbColumnBinding(fd, cliType);
		*cpp = cb;
		cpp = &cb->next;
	    } else { 
		response = cli_incompatible_type;