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// message.h
/* Copyright 2009 10gen Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include "sock.h"
#include "../../bson/util/atomic_int.h"
#include "hostandport.h"
namespace mongo {
class Message;
class MessagingPort;
class PiggyBackData;
typedef AtomicUInt MSGID;
enum Operations {
opReply = 1, /* reply. responseTo is set. */
dbMsg = 1000, /* generic msg command followed by a string */
dbUpdate = 2001, /* update object */
dbInsert = 2002,
//dbGetByOID = 2003,
dbQuery = 2004,
dbGetMore = 2005,
dbDelete = 2006,
dbKillCursors = 2007
};
bool doesOpGetAResponse( int op );
inline const char * opToString( int op ) {
switch ( op ) {
case 0: return "none";
case opReply: return "reply";
case dbMsg: return "msg";
case dbUpdate: return "update";
case dbInsert: return "insert";
case dbQuery: return "query";
case dbGetMore: return "getmore";
case dbDelete: return "remove";
case dbKillCursors: return "killcursors";
default:
massert( 16141, str::stream() << "cannot translate opcode " << op, !op );
return "";
}
}
inline bool opIsWrite( int op ) {
switch ( op ) {
case 0:
case opReply:
case dbMsg:
case dbQuery:
case dbGetMore:
case dbKillCursors:
return false;
case dbUpdate:
case dbInsert:
case dbDelete:
return true;
default:
PRINT(op);
verify(0);
return "";
}
}
#pragma pack(1)
/* see http://dochub.mongodb.org/core/mongowireprotocol
*/
struct MSGHEADER {
int messageLength; // total message size, including this
int requestID; // identifier for this message
int responseTo; // requestID from the original request
// (used in reponses from db)
int opCode;
};
#pragma pack()
#pragma pack(1)
/* todo merge this with MSGHEADER (or inherit from it). */
struct MsgData {
int len; /* len of the msg, including this field */
MSGID id; /* request/reply id's match... */
MSGID responseTo; /* id of the message we are responding to */
short _operation;
char _flags;
char _version;
int operation() const {
return _operation;
}
void setOperation(int o) {
_flags = 0;
_version = 0;
_operation = o;
}
char _data[4];
int& dataAsInt() {
return *((int *) _data);
}
bool valid() {
if ( len <= 0 || len > ( 4 * BSONObjMaxInternalSize ) )
return false;
if ( _operation < 0 || _operation > 30000 )
return false;
return true;
}
long long getCursor() {
verify( responseTo > 0 );
verify( _operation == opReply );
long long * l = (long long *)(_data + 4);
return l[0];
}
int dataLen(); // len without header
};
const int MsgDataHeaderSize = sizeof(MsgData) - 4;
inline int MsgData::dataLen() {
return len - MsgDataHeaderSize;
}
#pragma pack()
class Message {
public:
// we assume here that a vector with initial size 0 does no allocation (0 is the default, but wanted to make it explicit).
Message() : _buf( 0 ), _data( 0 ), _freeIt( false ) {}
Message( void * data , bool freeIt ) :
_buf( 0 ), _data( 0 ), _freeIt( false ) {
_setData( reinterpret_cast< MsgData* >( data ), freeIt );
};
Message(Message& r) : _buf( 0 ), _data( 0 ), _freeIt( false ) {
*this = r;
}
~Message() {
reset();
}
SockAddr _from;
MsgData *header() const {
verify( !empty() );
return _buf ? _buf : reinterpret_cast< MsgData* > ( _data[ 0 ].first );
}
int operation() const { return header()->operation(); }
MsgData *singleData() const {
massert( 13273, "single data buffer expected", _buf );
return header();
}
bool empty() const { return !_buf && _data.empty(); }
int size() const {
int res = 0;
if ( _buf ) {
res = _buf->len;
}
else {
for (MsgVec::const_iterator it = _data.begin(); it != _data.end(); ++it) {
res += it->second;
}
}
return res;
}
int dataSize() const { return size() - sizeof(MSGHEADER); }
// concat multiple buffers - noop if <2 buffers already, otherwise can be expensive copy
// can get rid of this if we make response handling smarter
void concat() {
if ( _buf || empty() ) {
return;
}
verify( _freeIt );
int totalSize = 0;
for( vector< pair< char *, int > >::const_iterator i = _data.begin(); i != _data.end(); ++i ) {
totalSize += i->second;
}
char *buf = (char*)malloc( totalSize );
char *p = buf;
for( vector< pair< char *, int > >::const_iterator i = _data.begin(); i != _data.end(); ++i ) {
memcpy( p, i->first, i->second );
p += i->second;
}
reset();
_setData( (MsgData*)buf, true );
}
// vector swap() so this is fast
Message& operator=(Message& r) {
verify( empty() );
verify( r._freeIt );
_buf = r._buf;
r._buf = 0;
if ( r._data.size() > 0 ) {
_data.swap( r._data );
}
r._freeIt = false;
_freeIt = true;
return *this;
}
void reset() {
if ( _freeIt ) {
if ( _buf ) {
free( _buf );
}
for( vector< pair< char *, int > >::const_iterator i = _data.begin(); i != _data.end(); ++i ) {
free(i->first);
}
}
_buf = 0;
_data.clear();
_freeIt = false;
}
// use to add a buffer
// assumes message will free everything
void appendData(char *d, int size) {
if ( size <= 0 ) {
return;
}
if ( empty() ) {
MsgData *md = (MsgData*)d;
md->len = size; // can be updated later if more buffers added
_setData( md, true );
return;
}
verify( _freeIt );
if ( _buf ) {
_data.push_back( make_pair( (char*)_buf, _buf->len ) );
_buf = 0;
}
_data.push_back( make_pair( d, size ) );
header()->len += size;
}
// use to set first buffer if empty
void setData(MsgData *d, bool freeIt) {
verify( empty() );
_setData( d, freeIt );
}
void setData(int operation, const char *msgtxt) {
setData(operation, msgtxt, strlen(msgtxt)+1);
}
void setData(int operation, const char *msgdata, size_t len) {
verify( empty() );
size_t dataLen = len + sizeof(MsgData) - 4;
MsgData *d = (MsgData *) malloc(dataLen);
memcpy(d->_data, msgdata, len);
d->len = fixEndian(dataLen);
d->setOperation(operation);
_setData( d, true );
}
bool doIFreeIt() {
return _freeIt;
}
void send( MessagingPort &p, const char *context );
string toString() const;
private:
void _setData( MsgData *d, bool freeIt ) {
_freeIt = freeIt;
_buf = d;
}
// if just one buffer, keep it in _buf, otherwise keep a sequence of buffers in _data
MsgData * _buf;
// byte buffer(s) - the first must contain at least a full MsgData unless using _buf for storage instead
typedef vector< pair< char*, int > > MsgVec;
MsgVec _data;
bool _freeIt;
};
MSGID nextMessageId();
} // namespace mongo
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