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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/>.
*/
#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/path_support.h"
namespace mongo {
struct ModifierPop::PreparedState {
PreparedState(mutablebson::Document* targetDoc)
: doc(*targetDoc)
, elementToRemove(doc.end())
, pathFoundIndex(0)
, pathFoundElement(doc.end())
, pathPositionalPart() {
}
// 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.
int32_t pathFoundIndex;
// Element corresponding to _fieldRef[0.._idxFound].
mutablebson::Element pathFoundElement;
// Value to bind to a $-positional field, if one is provided.
std::string pathPositionalPart;
};
ModifierPop::ModifierPop()
: _fieldRef()
, _positionalPathIndex(0)
, _fromTop(false) {
}
ModifierPop::~ModifierPop() {
}
Status ModifierPop::init(const BSONElement& modExpr) {
//
// 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 $-positional operator was used, get the index in which it occurred
// and ensure only one occurrence.
size_t foundCount;
bool foundDollar = fieldchecker::isPositional(_fieldRef,
&_positionalPathIndex,
&foundCount);
if (foundDollar && foundCount > 1) {
return Status(ErrorCodes::BadValue, "too many positional($) elements found.");
}
//
// 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,
const 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, "matched field not provided");
}
_preparedState->pathPositionalPart = matchedField.toString();
_fieldRef.setPart(_positionalPathIndex, _preparedState->pathPositionalPart);
}
// 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()) {
// If the path exists, we require the target field to be already an
// array.
if (_preparedState->pathFoundElement.getType() != Array) {
return Status(ErrorCodes::BadValue, "can only $pop from arrays");
}
// No children, nothing to do -- not an error state
if (!_preparedState->pathFoundElement.hasChildren()) {
execInfo->noOp = execInfo->inPlace = 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 = execInfo->inPlace = 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(mutablebson::Element logRoot) const {
// log document
mutablebson::Document& doc = logRoot.getDocument();
const bool pathExists = _preparedState->pathFoundElement.ok() &&
(_preparedState->pathFoundIndex ==
static_cast<int32_t>(_fieldRef.numParts() - 1));
// element to log, like $set/$unset
mutablebson::Element opElement = pathExists ?
doc.makeElementObject("$set") :
doc.makeElementObject("$unset");
if (!opElement.ok()) {
return Status(ErrorCodes::InternalError, "cannot create log entry");
}
// value for the logElement ("field.path.name": <value>)
mutablebson::Element logElement = pathExists ?
logRoot.getDocument().makeElementWithNewFieldName(
_fieldRef.dottedField(),
_preparedState->pathFoundElement
):
doc.makeElementBool(_fieldRef.dottedField(), true);
if (!logElement.ok()) {
return Status(ErrorCodes::InternalError, "cannot create details");
}
// Now, we attach the {<fieldname>: <value>} Element under the {$op: ...} one.
Status status = opElement.pushBack(logElement);
if (!status.isOK()) {
return status;
}
// And attach the result under the 'logRoot' Element provided.
return logRoot.pushBack(opElement);
}
} // namespace mongo
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