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/**
* Copyright (C) 2013 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/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects
* for all of the code used other than as permitted herein. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you do not
* wish to do so, delete this exception statement from your version. If you
* delete this exception statement from all source files in the program,
* then also delete it in the license file.
*/
#include "mongo/db/ops/modifier_compare.h"
#include "mongo/base/error_codes.h"
#include "mongo/bson/mutable/document.h"
#include "mongo/db/ops/field_checker.h"
#include "mongo/db/ops/log_builder.h"
#include "mongo/db/ops/path_support.h"
#include "mongo/util/mongoutils/str.h"
namespace mongo {
namespace str = mongoutils::str;
struct ModifierCompare::PreparedState {
PreparedState(mutablebson::Document& targetDoc)
: doc(targetDoc), idxFound(0), elemFound(doc.end()) {}
// Document that is going to be changed.
mutablebson::Document& doc;
// Index in _fieldRef for which an Element exist in the document.
size_t idxFound;
// Element corresponding to _fieldRef[0.._idxFound].
mutablebson::Element elemFound;
};
ModifierCompare::ModifierCompare(ModifierCompare::ModifierCompareMode mode)
: _mode(mode), _pathReplacementPosition(0) {}
ModifierCompare::~ModifierCompare() {}
Status ModifierCompare::init(const BSONElement& modExpr, const Options& opts, bool* positional) {
_updatePath.parse(modExpr.fieldName());
Status status = fieldchecker::isUpdatable(_updatePath);
if (!status.isOK()) {
return status;
}
// If a $-positional operator was used, get the index in which it occurred
// and ensure only one occurrence.
size_t foundCount;
bool foundDollar =
fieldchecker::isPositional(_updatePath, &_pathReplacementPosition, &foundCount);
if (positional)
*positional = foundDollar;
if (foundDollar && foundCount > 1) {
return Status(ErrorCodes::BadValue,
str::stream() << "Too many positional (i.e. '$') elements found in path '"
<< _updatePath.dottedField() << "'");
}
// Store value for later.
_val = modExpr;
return Status::OK();
}
Status ModifierCompare::prepare(mutablebson::Element root,
StringData matchedField,
ExecInfo* execInfo) {
_preparedState.reset(new PreparedState(root.getDocument()));
// If we have a $-positional field, it is time to bind it to an actual field part.
if (_pathReplacementPosition) {
if (matchedField.empty()) {
return Status(ErrorCodes::BadValue,
str::stream() << "The positional operator did not find the match "
"needed from the query. Unexpanded update: "
<< _updatePath.dottedField());
}
_updatePath.setPart(_pathReplacementPosition, matchedField);
}
// Locate the field name in 'root'. Note that we may not have all the parts in the path
// in the doc -- which is fine. Our goal now is merely to reason about whether this mod
// apply is a noOp or whether is can be in place. The remaining path, if missing, will
// be created during the apply.
Status status = pathsupport::findLongestPrefix(
_updatePath, root, &_preparedState->idxFound, &_preparedState->elemFound);
// FindLongestPrefix may say the path does not exist at all, which is fine here, or
// that the path was not viable or otherwise wrong, in which case, the mod cannot
// proceed.
if (status.code() == ErrorCodes::NonExistentPath) {
_preparedState->elemFound = root.getDocument().end();
} else if (!status.isOK()) {
return status;
}
// We register interest in the field name. The driver needs this info to sort out if
// there is any conflict among mods.
execInfo->fieldRef[0] = &_updatePath;
const bool destExists = (_preparedState->elemFound.ok() &&
_preparedState->idxFound == (_updatePath.numParts() - 1));
if (!destExists) {
execInfo->noOp = false;
} else {
const int compareVal = _preparedState->elemFound.compareWithBSONElement(_val, false);
execInfo->noOp = (compareVal == 0) ||
((_mode == ModifierCompare::MAX) ? (compareVal > 0) : (compareVal < 0));
}
return Status::OK();
}
Status ModifierCompare::apply() const {
const bool destExists = (_preparedState->elemFound.ok() &&
_preparedState->idxFound == (_updatePath.numParts() - 1));
// If there's no need to create any further field part, the $set is simply a value
// assignment.
if (destExists) {
return _preparedState->elemFound.setValueBSONElement(_val);
}
mutablebson::Document& doc = _preparedState->doc;
StringData lastPart = _updatePath.getPart(_updatePath.numParts() - 1);
// If the element exists and is the same type, then that is what we want to work with
mutablebson::Element elemToSet = doc.makeElementWithNewFieldName(lastPart, _val);
if (!elemToSet.ok()) {
return Status(ErrorCodes::InternalError, "can't create new element");
}
// Now, we can be in two cases here, as far as attaching the element being set goes:
// (a) none of the parts in the element's path exist, or (b) some parts of the path
// exist but not all.
if (!_preparedState->elemFound.ok()) {
_preparedState->elemFound = doc.root();
_preparedState->idxFound = 0;
} else {
_preparedState->idxFound++;
}
// createPathAt() will complete the path and attach 'elemToSet' at the end of it.
return pathsupport::createPathAt(
_updatePath, _preparedState->idxFound, _preparedState->elemFound, elemToSet);
}
Status ModifierCompare::log(LogBuilder* logBuilder) const {
return logBuilder->addToSetsWithNewFieldName(_updatePath.dottedField(), _val);
}
} // namespace mongo
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