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/** @file mongo/scripting/templateevaluator.cpp */
/*
* Copyright (C) 2012 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/>.
*/
#include "mongo/scripting/bson_template_evaluator.h"
#include <cstddef>
#include <cstdlib>
#include "mongo/util/map_util.h"
namespace mongo {
void BsonTemplateEvaluator::initializeEvaluator() {
addOperator("RAND_INT", &BsonTemplateEvaluator::evalRandInt);
addOperator("RAND_STRING", &BsonTemplateEvaluator::evalRandString);
addOperator("CONCAT", &BsonTemplateEvaluator::evalConcat);
}
BsonTemplateEvaluator::BsonTemplateEvaluator() {
initializeEvaluator();
}
void BsonTemplateEvaluator::addOperator(const std::string& name, const OperatorFn& op) {
_operatorFunctions[name] = op;
}
BsonTemplateEvaluator::OperatorFn BsonTemplateEvaluator::operatorEvaluator(
const std::string& op) const {
return mapFindWithDefault(_operatorFunctions, op, OperatorFn());
}
/* This is the top level method for using this library. It takes a BSON Object as input,
* evaluates the templates and saves the result in the builder object.
* The method returns appropriate Status on success/error condition.
*/
BsonTemplateEvaluator::Status BsonTemplateEvaluator::evaluate(const BSONObj& in,
BSONObjBuilder& builder) {
BSONForEach(e, in) {
Status st = _evalElem(e, builder);
if (st != StatusSuccess)
return st;
}
return StatusSuccess;
}
BsonTemplateEvaluator::Status BsonTemplateEvaluator::_evalElem(BSONElement in,
BSONObjBuilder& out) {
if (in.type() != Object) {
out.append(in);
return StatusSuccess;
}
BSONObj subObj = in.embeddedObject();
const char* opOrNot = subObj.firstElementFieldName();
if (opOrNot[0] != '#') {
out.append(in);
return StatusSuccess;
}
const char* op = opOrNot+1;
OperatorFn fn = operatorEvaluator(op);
if (!fn)
return StatusBadOperator;
Status st = fn(this, in.fieldName(), subObj, out);
if (st != StatusSuccess)
return st;
return StatusSuccess;
}
BsonTemplateEvaluator::Status BsonTemplateEvaluator::evalRandInt(BsonTemplateEvaluator* btl,
const char* fieldName,
const BSONObj in,
BSONObjBuilder& out) {
// in = { #RAND_INT: [10, 20] }
BSONObj range = in.firstElement().embeddedObject();
if (!range[0].isNumber() || !range[1].isNumber())
return StatusOpEvaluationError;
const int min = range["0"].numberInt();
const int max = range["1"].numberInt();
if (max <= min)
return StatusOpEvaluationError;
int randomNum = min + (rand() % (max - min));
if (range.nFields() == 3) {
if (!range[2].isNumber())
return StatusOpEvaluationError;
randomNum *= range[2].numberInt();
}
out.append(fieldName, randomNum);
return StatusSuccess;
}
BsonTemplateEvaluator::Status BsonTemplateEvaluator::evalRandString(BsonTemplateEvaluator* btl,
const char* fieldName,
const BSONObj in,
BSONObjBuilder& out) {
// in = { #RAND_STRING: [10] }
BSONObj range = in.firstElement().embeddedObject();
if (range.nFields() != 1)
return StatusOpEvaluationError;
if (!range[0].isNumber())
return StatusOpEvaluationError;
const int length = range["0"].numberInt();
if (length <= 0)
return StatusOpEvaluationError;
static const char alphanum[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/";
static const size_t alphaNumLength = sizeof(alphanum) - 1;
BOOST_STATIC_ASSERT(alphaNumLength == 64);
unsigned currentRand = 0;
std::string str;
for (int i = 0; i < length; ++i, currentRand >>= 6) {
if (i % 5 == 0)
currentRand = rand();
str.push_back(alphanum[currentRand % alphaNumLength]);
}
out.append(fieldName, str);
return StatusSuccess;
}
BsonTemplateEvaluator::Status BsonTemplateEvaluator::evalConcat(BsonTemplateEvaluator* btl,
const char* fieldName,
const BSONObj in,
BSONObjBuilder& out) {
// in = { #CONCAT: ["hello", " ", "world"] }
BSONObjBuilder objectBuilder;
Status status = btl->evaluate(in.firstElement().embeddedObject(), objectBuilder);
if (status != StatusSuccess)
return status;
BSONObj parts = objectBuilder.obj();
if (parts.nFields() <= 1)
return StatusOpEvaluationError;
StringBuilder stringBuilder;
BSONForEach(part, parts) {
if (part.type() == String)
stringBuilder << part.String();
else
part.toString(stringBuilder,false);
}
out.append(fieldName, stringBuilder.str());
return StatusSuccess;
}
} // end namespace mongo
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