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Diffstat (limited to 'src/mongo/scripting/bson_template_evaluator.cpp')
| -rw-r--r-- | src/mongo/scripting/bson_template_evaluator.cpp | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/src/mongo/scripting/bson_template_evaluator.cpp b/src/mongo/scripting/bson_template_evaluator.cpp new file mode 100644 index 00000000000..b38bed37051 --- /dev/null +++ b/src/mongo/scripting/bson_template_evaluator.cpp @@ -0,0 +1,157 @@ +/** @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 |