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// query.h
#pragma once
#include "../stdafx.h"
#include "../grid/message.h"
#include "jsobj.h"
#include "storage.h"
/* requests:
dbDelete
int reserved=0;
string collection;
int flags=0; // 1=DeleteSingle
JSObject query;
dbUpdate:
int reserved;
string collection;
int flags; // 1=upsert
JSObject query;
JSObject objectToUpdate;
objectToUpdate may include { $inc: <field> }.
dbQuery:
int reserved;
string collection;
int nToSkip;
int nToReturn; // how many you want back as the beginning of the cursor data
JSObject query;
[JSObject fieldsToReturn]
dbGetMore:
int reserved;
string collection; // redundant, might use for security.
int nToReturn;
int64 cursorID;
dbKillCursors=2007:
int reserved;
int n;
int64 cursorIDs[n];
Note that on Update, there is only one object, which is different
from insert where you can pass a list of objects to insert in the db.
Note that the update field layout is very similar layout to Query.
*/
/* db response format
Query or GetMore:
int reserved;
int64 cursorID;
int startingFrom;
int nReturned; // 0=infinity
list of marshalled JSObjects;
*/
#pragma pack(push)
#pragma pack(1)
struct QueryResult : public MsgData {
long long cursorId;
int startingFrom;
int nReturned;
const char *data() { return (char *) (((int *)&nReturned)+1); }
};
#pragma pack(pop)
QueryResult* getMore(const char *ns, int ntoreturn, long long cursorid);
// caller must free() returned QueryResult.
QueryResult* runQuery(const char *ns, int ntoskip, int ntoreturn,
JSObj j, auto_ptr< set<string> > fieldFilter,
stringstream&);
void updateObjects(const char *ns, JSObj updateobj, JSObj pattern, bool upsert, stringstream& ss);
void deleteObjects(const char *ns, JSObj pattern, bool justOne);
class ClientCursor;
typedef map<long long, ClientCursor*> CCMap;
extern CCMap clientCursors; /* cursorid -> ClientCursor */
/* Cursor -- and its derived classes -- are our internal cursors.
ClientCursor is a wrapper that represents a cursorid from our client
application's perspective.
*/
class Cursor;
class ClientCursor {
friend class CursInspector;
public:
ClientCursor() {
cursorid=0; pos=0; nextAtThisLocation=0;
#if defined(_WIN32)
cout << "clientcursor() " << cursorid << endl;
#endif
}
~ClientCursor();
long long cursorid;
string ns;
auto_ptr<JSMatcher> matcher;
auto_ptr<Cursor> c;
int pos;
DiskLoc lastLoc;
auto_ptr< set<string> > filter;
/* report to us that a new clientcursor exists so we can track it. You still
do the initial updateLocation() yourself.
*/
static void add(ClientCursor*);
static bool erase(long long cursorid);
static ClientCursor* find(long long id) {
CCMap::iterator it = clientCursors.find(id);
if( it == clientCursors.end() ) {
cout << "ClientCursor::find(): cursor not found in map " << id << endl;
return 0;
}
return it->second;
}
/* call when cursor's location changes so that we can update the
cursorsbylocation map. if you are locked and internally iterating, only
need to call when you are ready to "unlock".
*/
void updateLocation();
private:
void addToByLocation(DiskLoc cl);
static void cleanupByLocation(DiskLoc loc, long long cursorid);
public:
ClientCursor *nextAtThisLocation;
};
long long allocCursorId();
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