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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_pop.h"
#include "mongo/base/error_codes.h"
#include "mongo/bson/mutable/algorithm.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 mb = mutablebson;
namespace str = mongoutils::str;
struct ModifierPop::PreparedState {
PreparedState(mutablebson::Document* targetDoc)
: doc(*targetDoc)
, elementToRemove(doc.end())
, pathFoundIndex(0)
, pathFoundElement(doc.end()) {
}
// Document that is going to be changed.
mutablebson::Document& doc;
// Element to be removed
mutablebson::Element elementToRemove;
// Index in _fieldRef for which an Element exist in the document.
size_t pathFoundIndex;
// Element corresponding to _fieldRef[0.._idxFound].
mutablebson::Element pathFoundElement;
};
ModifierPop::ModifierPop()
: _fieldRef()
, _positionalPathIndex(0)
, _fromTop(false) {
}
ModifierPop::~ModifierPop() {
}
Status ModifierPop::init(const BSONElement& modExpr, const Options& opts,
bool* positional) {
//
// field name analysis
//
// Break down the field name into its 'dotted' components (aka parts) and check that
// there are no empty parts.
_fieldRef.parse(modExpr.fieldName());
Status status = fieldchecker::isUpdatable(_fieldRef);
if (! status.isOK()) {
return status;
}
// If a $-positional operator was used, get the index in which it occurred
// and ensure only one occurrence.
size_t foundCount;
bool foundDollar = fieldchecker::isPositional(_fieldRef,
&_positionalPathIndex,
&foundCount);
if (positional)
*positional = foundDollar;
if (foundDollar && foundCount > 1) {
return Status(ErrorCodes::BadValue,
str::stream() << "Too many positional (i.e. '$') elements found in path '"
<< _fieldRef.dottedField() << "'");
}
//
// value analysis
//
// TODO: tighten validation to numbers and just 1/-1 explicitly
//if (!modExpr.isNumber()) {
// return Status(ErrorCodes::BadValue, "Must be a number");
//}
_fromTop = (modExpr.isNumber() && modExpr.number() < 0) ? true : false;
return Status::OK();
}
Status ModifierPop::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 (_positionalPathIndex) {
if (matchedField.empty()) {
return Status(ErrorCodes::BadValue,
str::stream() << "The positional operator did not find the match "
"needed from the query. Unexpanded update: "
<< _fieldRef.dottedField());
}
_fieldRef.setPart(_positionalPathIndex, matchedField);
}
// Locate the field name in 'root'. Note that if we don't have the full path in the
// doc, there isn't anything to unset, really.
Status status = pathsupport::findLongestPrefix(_fieldRef,
root,
&_preparedState->pathFoundIndex,
&_preparedState->pathFoundElement);
// Check if we didn't find the full path
if (status.isOK()) {
const bool destExists = (_preparedState->pathFoundIndex == (_fieldRef.numParts()-1));
if (!destExists) {
execInfo->noOp = true;
} else {
// If the path exists, we require the target field to be already an
// array.
if (_preparedState->pathFoundElement.getType() != Array) {
mb::Element idElem = mb::findFirstChildNamed(root, "_id");
return Status(
ErrorCodes::BadValue,
str::stream() << "Can only $pop from arrays. {"
<< idElem.toString()
<< "} has the field '"
<< _preparedState->pathFoundElement.getFieldName()
<< "' of non-array type "
<< typeName(_preparedState->pathFoundElement.getType()));
}
// No children, nothing to do -- not an error state
if (!_preparedState->pathFoundElement.hasChildren()) {
execInfo->noOp = true;
} else {
_preparedState->elementToRemove = _fromTop ?
_preparedState->pathFoundElement.leftChild() :
_preparedState->pathFoundElement.rightChild();
}
}
} else {
// Let the caller know we can't do anything given the mod, _fieldRef, and doc.
execInfo->noOp = true;
_preparedState->pathFoundElement = root.getDocument().end();
//okay if path not found
if (status.code() == ErrorCodes::NonExistentPath)
status = Status::OK();
}
// Let the caller know what field we care about
execInfo->fieldRef[0] = &_fieldRef;
return status;
}
Status ModifierPop::apply() const {
return _preparedState->elementToRemove.remove();
}
Status ModifierPop::log(LogBuilder* logBuilder) const {
// log document
mutablebson::Document& doc = logBuilder->getDocument();
const bool pathExists = _preparedState->pathFoundElement.ok() &&
(_preparedState->pathFoundIndex == (_fieldRef.numParts() - 1));
if (!pathExists)
return logBuilder->addToUnsets(_fieldRef.dottedField());
// value for the logElement ("field.path.name": <value>)
mutablebson::Element logElement = doc.makeElementWithNewFieldName(
_fieldRef.dottedField(),
_preparedState->pathFoundElement);
if (!logElement.ok()) {
return Status(ErrorCodes::InternalError,
str::stream() << "Could not append entry to $pop oplog entry: "
<< "set '" << _fieldRef.dottedField() << "' -> "
<< _preparedState->pathFoundElement.toString() );
}
return logBuilder->addToSets(logElement);
}
} // namespace mongo
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