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/**
* Copyright (C) 2008 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/* clientcursor.cpp
ClientCursor is a wrapper that represents a cursorid from our client
application's perspective.
Cursor -- and its derived classes -- are our internal cursors.
*/
#include "stdafx.h"
#include "query.h"
#include "introspect.h"
#include <time.h>
/* TODO: FIX cleanup of clientCursors when hit the end. (ntoreturn insufficient) */
CCById clientCursorsById;
/* ------------------------------------------- */
typedef multimap<DiskLoc, ClientCursor*> ByLoc;
ByLoc byLoc;
void ClientCursor::setLastLoc(DiskLoc L) {
if( L == _lastLoc )
return;
if( !_lastLoc.isNull() ) {
ByLoc::iterator i = kv_find(byLoc, _lastLoc, this);
if( i != byLoc.end() )
byLoc.erase(i);
}
if( !L.isNull() )
byLoc.insert( make_pair(L, this) );
_lastLoc = L;
}
/* ------------------------------------------- */
/* must call this when a btree node is updated */
//void removedKey(const DiskLoc& btreeLoc, int keyPos) {
//}
/* todo: this implementation is incomplete. we use it as a prefix for dropDatabase, which
works fine as the prefix will end with '.'. however, when used with drop and
deleteIndexes, this could take out cursors that belong to something else -- if you
drop "foo", currently, this will kill cursors for "foobar".
*/
void ClientCursor::invalidate(const char *nsPrefix) {
vector<ClientCursor*> toDelete;
int len = strlen(nsPrefix);
assert( len > 0 && strchr(nsPrefix, '.') );
for( ByLoc::iterator i = byLoc.begin(); i != byLoc.end(); ++i ) {
ClientCursor *cc = i->second;
if( strncmp(nsPrefix, cc->ns.c_str(), len) == 0 )
toDelete.push_back(i->second);
}
for( vector<ClientCursor*>::iterator i = toDelete.begin(); i != toDelete.end(); ++i )
delete (*i);
}
/* must call when a btree bucket going away.
note this is potentially slow
*/
void aboutToDeleteBucket(const DiskLoc& b) {
RARELY if( byLoc.size() > 70 ) {
log() << "perf warning: byLoc.size=" << byLoc.size() << " in aboutToDeleteBucket\n";
}
for( ByLoc::iterator i = byLoc.begin(); i != byLoc.end(); i++ )
i->second->c->aboutToDeleteBucket(b);
}
/* must call this on a delete so we clean up the cursors. */
void aboutToDelete(const DiskLoc& dl) {
vector<ClientCursor*> toAdvance;
for( ByLoc::iterator i = byLoc.lower_bound(dl);
i != byLoc.upper_bound(dl); ++i ) {
toAdvance.push_back(i->second);
}
for( vector<ClientCursor*>::iterator i = toAdvance.begin();
i != toAdvance.end(); ++i )
{
Cursor *c = (*i)->c.get();
DiskLoc tmp1 = c->currLoc();
if( tmp1 != dl ) {
/* this might indicate a failure to call ClientCursor::updateLocation() */
problem() << "warning: cursor loc does not match byLoc position!" << endl;
}
c->checkLocation();
if( c->tailing() ) {
DEV cout << "killing cursor as we would have to advance it and it is tailable" << endl;
delete *i;
continue;
}
c->advance();
DiskLoc newLoc = c->currLoc();
if( newLoc.isNull() ) {
// advanced to end -- delete cursor
delete *i;
}
else {
wassert( newLoc != dl );
(*i)->updateLocation();
}
}
}
ClientCursor::~ClientCursor() {
assert( pos != -2 );
setLastLoc( DiskLoc() ); // removes us from bylocation multimap
clientCursorsById.erase(cursorid);
// defensive:
(CursorId&) cursorid = -1;
pos = -2;
}
/* 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 ClientCursor::updateLocation() {
assert( cursorid );
DiskLoc cl = c->currLoc();
if( lastLoc() == cl ) {
//log() << "info: lastloc==curloc " << ns << '\n';
return;
}
setLastLoc(cl);
c->noteLocation();
}
int ctmLast = 0; // so we don't have to do find() which is a little slow very often.
long long ClientCursor::allocCursorId() {
long long x;
int ctm = (int) curTimeMillis();
while( 1 ) {
x = (((long long)rand()) << 32);
x = x | ctm | 0x80000000; // OR to make sure not zero
if( ctm != ctmLast || ClientCursor::find(x, false) == 0 )
break;
}
ctmLast = ctm;
DEV cout << " alloccursorid " << x << endl;
return x;
}
class CursInspector : public SingleResultObjCursor {
Cursor* clone() {
return new CursInspector();
}
void fill() {
b.append("byLocation_size", byLoc.size());
b.append("clientCursors_size", clientCursorsById.size());
/* todo update for new impl:
stringstream ss;
ss << '\n';
int x = 40;
DiskToCC::iterator it = clientCursorsByLocation.begin();
while( it != clientCursorsByLocation.end() ) {
DiskLoc dl = it->first;
ss << dl.toString() << " -> \n";
set<ClientCursor*>::iterator j = it->second.begin();
while( j != it->second.end() ) {
ss << " cid:" << j->second->cursorid << ' ' << j->second->ns << " pos:" << j->second->pos << " LL:" << j->second->lastLoc.toString();
try {
setClient(j->second->ns.c_str());
Record *r = dl.rec();
ss << " lwh:" << hex << r->lengthWithHeaders << " nxt:" << r->nextOfs << " prv:" << r->prevOfs << dec << ' ' << j->second->c->toString();
if( r->nextOfs >= 0 && r->nextOfs < 16 )
ss << " DELETED??? (!)";
}
catch(...) {
ss << " EXCEPTION";
}
ss << "\n";
j++;
}
if( --x <= 0 ) {
ss << "only first 40 shown\n" << endl;
break;
}
it++;
}
b.append("dump", ss.str().c_str());
*/
}
public:
CursInspector() { reg("intr.cursors"); }
} _ciproto;
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