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// group.cpp
/**
*
* 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/>.
*/
#include "pch.h"
#include "../commands.h"
#include "../instance.h"
#include "../queryoptimizer.h"
namespace mongo {
class GroupCommand : public Command {
public:
GroupCommand() : Command("group") {}
virtual LockType locktype() const { return READ; }
virtual bool slaveOk() const { return false; }
virtual bool slaveOverrideOk() { return true; }
virtual void help( stringstream &help ) const {
help << "http://www.mongodb.org/display/DOCS/Aggregation";
}
BSONObj getKey( const BSONObj& obj , const BSONObj& keyPattern , ScriptingFunction func , double avgSize , Scope * s ) {
if ( func ) {
BSONObjBuilder b( obj.objsize() + 32 );
b.append( "0" , obj );
int res = s->invoke( func , b.obj() );
uassert( 10041 , (string)"invoke failed in $keyf: " + s->getError() , res == 0 );
int type = s->type("return");
uassert( 10042 , "return of $key has to be an object" , type == Object );
return s->getObject( "return" );
}
return obj.extractFields( keyPattern , true );
}
bool group( string realdbname , const string& ns , const BSONObj& query ,
BSONObj keyPattern , string keyFunctionCode , string reduceCode , const char * reduceScope ,
BSONObj initial , string finalize ,
string& errmsg , BSONObjBuilder& result ) {
auto_ptr<Scope> s = globalScriptEngine->getPooledScope( realdbname );
s->localConnect( realdbname.c_str() );
if ( reduceScope )
s->init( reduceScope );
s->setObject( "$initial" , initial , true );
s->exec( "$reduce = " + reduceCode , "reduce setup" , false , true , true , 100 );
s->exec( "$arr = [];" , "reduce setup 2" , false , true , true , 100 );
ScriptingFunction f = s->createFunction(
"function(){ "
" if ( $arr[n] == null ){ "
" next = {}; "
" Object.extend( next , $key ); "
" Object.extend( next , $initial , true ); "
" $arr[n] = next; "
" next = null; "
" } "
" $reduce( obj , $arr[n] ); "
"}" );
ScriptingFunction keyFunction = 0;
if ( keyFunctionCode.size() ) {
keyFunction = s->createFunction( keyFunctionCode.c_str() );
}
double keysize = keyPattern.objsize() * 3;
double keynum = 1;
map<BSONObj,int,BSONObjCmp> map;
list<BSONObj> blah;
shared_ptr<Cursor> cursor = bestGuessCursor(ns.c_str() , query , BSONObj() );
while ( cursor->ok() ) {
if ( cursor->matcher() && ! cursor->matcher()->matchesCurrent( cursor.get() ) ) {
cursor->advance();
continue;
}
BSONObj obj = cursor->current();
cursor->advance();
BSONObj key = getKey( obj , keyPattern , keyFunction , keysize / keynum , s.get() );
keysize += key.objsize();
keynum++;
int& n = map[key];
if ( n == 0 ) {
n = map.size();
s->setObject( "$key" , key , true );
uassert( 10043 , "group() can't handle more than 20000 unique keys" , n <= 20000 );
}
s->setObject( "obj" , obj , true );
s->setNumber( "n" , n - 1 );
if ( s->invoke( f , BSONObj() , 0 , true ) ) {
throw UserException( 9010 , (string)"reduce invoke failed: " + s->getError() );
}
}
if (!finalize.empty()) {
s->exec( "$finalize = " + finalize , "finalize define" , false , true , true , 100 );
ScriptingFunction g = s->createFunction(
"function(){ "
" for(var i=0; i < $arr.length; i++){ "
" var ret = $finalize($arr[i]); "
" if (ret !== undefined) "
" $arr[i] = ret; "
" } "
"}" );
s->invoke( g , BSONObj() , 0 , true );
}
result.appendArray( "retval" , s->getObject( "$arr" ) );
result.append( "count" , keynum - 1 );
result.append( "keys" , (int)(map.size()) );
s->exec( "$arr = [];" , "reduce setup 2" , false , true , true , 100 );
s->gc();
return true;
}
bool run(const string& dbname, BSONObj& jsobj, string& errmsg, BSONObjBuilder& result, bool fromRepl ) {
if ( !globalScriptEngine ) {
errmsg = "server-side JavaScript execution is disabled";
return false;
}
/* db.$cmd.findOne( { group : <p> } ) */
const BSONObj& p = jsobj.firstElement().embeddedObjectUserCheck();
BSONObj q;
if ( p["cond"].type() == Object )
q = p["cond"].embeddedObject();
else if ( p["condition"].type() == Object )
q = p["condition"].embeddedObject();
else
q = getQuery( p );
if ( p["ns"].type() != String ) {
errmsg = "ns has to be set";
return false;
}
string ns = dbname + "." + p["ns"].String();
BSONObj key;
string keyf;
if ( p["key"].type() == Object ) {
key = p["key"].embeddedObjectUserCheck();
if ( ! p["$keyf"].eoo() ) {
errmsg = "can't have key and $keyf";
return false;
}
}
else if ( p["$keyf"].type() ) {
keyf = p["$keyf"]._asCode();
}
else {
// no key specified, will use entire object as key
}
BSONElement reduce = p["$reduce"];
if ( reduce.eoo() ) {
errmsg = "$reduce has to be set";
return false;
}
BSONElement initial = p["initial"];
if ( initial.type() != Object ) {
errmsg = "initial has to be an object";
return false;
}
string finalize;
if (p["finalize"].type())
finalize = p["finalize"]._asCode();
return group( dbname , ns , q ,
key , keyf , reduce._asCode() , reduce.type() != CodeWScope ? 0 : reduce.codeWScopeScopeData() ,
initial.embeddedObject() , finalize ,
errmsg , result );
}
} cmdGroup;
} // namespace mongo
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