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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_add_to_set.h"
#include "mongo/base/error_codes.h"
#include "mongo/bson/mutable/algorithm.h"
#include "mongo/db/query/collation/collator_interface.h"
#include "mongo/db/update/field_checker.h"
#include "mongo/db/update/log_builder.h"
#include "mongo/db/update/path_support.h"
#include "mongo/util/mongoutils/str.h"
namespace mongo {
namespace mb = mutablebson;
namespace str = mongoutils::str;
namespace {
template <typename Ordering, typename Equality>
void deduplicate(mb::Element parent, Ordering comp, Equality equal) {
// First, build a vector of the children.
std::vector<mb::Element> children;
mb::Element current = parent.leftChild();
while (current.ok()) {
children.push_back(current);
current = current.rightSibling();
}
// Then, sort the child vector with our comparator.
std::sort(children.begin(), children.end(), comp);
// Next, remove duplicates by walking the vector.
std::vector<mb::Element>::iterator where = children.begin();
const std::vector<mb::Element>::iterator end = children.end();
while (where != end) {
std::vector<mb::Element>::iterator next = where;
++next;
while (next != end && equal(*where, *next)) {
next->remove().transitional_ignore();
++next;
}
where = next;
}
}
} // namespace
struct ModifierAddToSet::PreparedState {
PreparedState(mb::Document& doc)
: doc(doc),
idxFound(0),
elemFound(doc.end()),
addAll(false),
elementsToAdd(),
noOp(false) {}
// Document that is going to be changed.
mb::Document& doc;
// Index in _fieldRef for which an Element exist in the document.
size_t idxFound;
// Element corresponding to _fieldRef[0.._idxFound].
mb::Element elemFound;
// Are we adding all of the $each elements, or just a subset?
bool addAll;
// Values to be applied.
std::vector<mb::Element> elementsToAdd;
// True if this update is a no-op
bool noOp;
};
ModifierAddToSet::ModifierAddToSet()
: ModifierInterface(), _fieldRef(), _posDollar(0), _valDoc(), _val(_valDoc.end()) {}
ModifierAddToSet::~ModifierAddToSet() {}
Status ModifierAddToSet::init(const BSONElement& modExpr, const Options& opts, bool* positional) {
// Perform standard field name and updateable checks.
_fieldRef.parse(modExpr.fieldName());
Status status = fieldchecker::isUpdatable(_fieldRef);
if (!status.isOK()) {
return status;
}
// If a $-positional operator was used, get the index in which it occurred
// and ensure only one occurrence.
size_t foundCount;
bool foundDollar = fieldchecker::isPositional(_fieldRef, &_posDollar, &foundCount);
if (positional)
*positional = foundDollar;
if (foundDollar && foundCount > 1) {
return Status(ErrorCodes::BadValue,
str::stream() << "Too many positional (i.e. '$') elements found in path '"
<< _fieldRef.dottedField()
<< "'");
}
// TODO: The driver could potentially do this re-writing.
// If the type of the value is 'Object', we might be dealing with a $each. See if that
// is the case.
if (modExpr.type() == mongo::Object) {
BSONElement modExprObjPayload = modExpr.embeddedObject().firstElement();
if (!modExprObjPayload.eoo() && StringData(modExprObjPayload.fieldName()) == "$each") {
// It is a $each. Verify that the payload is an array as is required for $each,
// set our flag, and store the array as our value.
if (modExprObjPayload.type() != mongo::Array) {
return Status(ErrorCodes::BadValue,
str::stream() << "The argument to $each in $addToSet must "
"be an array but it was of type "
<< typeName(modExprObjPayload.type()));
}
status = _valDoc.root().appendElement(modExprObjPayload);
if (!status.isOK())
return status;
_val = _valDoc.root().leftChild();
}
}
// If this wasn't an 'each', turn it into one. No need to sort or de-dup since we only
// have one element.
if (_val == _valDoc.end()) {
mb::Element each = _valDoc.makeElementArray("$each");
status = each.appendElement(modExpr);
if (!status.isOK())
return status;
status = _valDoc.root().pushBack(each);
if (!status.isOK())
return status;
_val = each;
}
setCollator(opts.collator);
return Status::OK();
}
void ModifierAddToSet::setCollator(const CollatorInterface* collator) {
invariant(!_collator);
_collator = collator;
// Deduplicate _val (must be performed after collator is set to final value.)
deduplicate(_val, mb::woLess(_collator, false), mb::woEqual(_collator, false));
}
Status ModifierAddToSet::prepare(mb::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 (_posDollar) {
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(_posDollar, matchedField);
}
// Locate the field name in 'root'.
Status status = pathsupport::findLongestPrefix(
_fieldRef, 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] = &_fieldRef;
//
// in-place and no-op logic
//
// If the field path is not fully present, then this mod cannot be in place, nor is a
// noOp.
if (!_preparedState->elemFound.ok() || _preparedState->idxFound < (_fieldRef.numParts() - 1)) {
// If no target element exists, we will simply be creating a new array.
_preparedState->addAll = true;
return Status::OK();
}
// This operation only applies to arrays
if (_preparedState->elemFound.getType() != mongo::Array) {
mb::Element idElem = mb::findElementNamed(root.leftChild(), "_id");
return Status(ErrorCodes::BadValue,
str::stream() << "Cannot apply $addToSet to a non-array field. Field named '"
<< _preparedState->elemFound.getFieldName()
<< "' has a non-array type "
<< typeName(_preparedState->elemFound.getType())
<< " in the document "
<< idElem.toString());
}
// If the array is empty, then we don't need to check anything: all of the values are
// going to be added.
if (!_preparedState->elemFound.hasChildren()) {
_preparedState->addAll = true;
return Status::OK();
}
// For each value in the $each clause, compare it against the values in the array. If
// the element is not present, record it as one to add.
mb::Element eachIter = _val.leftChild();
while (eachIter.ok()) {
mb::Element where = mb::findElement(_preparedState->elemFound.leftChild(),
mb::woEqualTo(eachIter, _collator, false));
if (!where.ok()) {
// The element was not found. Record the element from $each as one to be added.
_preparedState->elementsToAdd.push_back(eachIter);
}
eachIter = eachIter.rightSibling();
}
// If we didn't find any elements to add, then this is a no-op.
if (_preparedState->elementsToAdd.empty()) {
_preparedState->noOp = execInfo->noOp = true;
}
return Status::OK();
}
Status ModifierAddToSet::apply() const {
dassert(_preparedState->noOp == false);
// TODO: The contents of this block are lifted directly from $push.
// If the array field is not there, create it as an array and attach it to the
// document.
if (!_preparedState->elemFound.ok() || _preparedState->idxFound < (_fieldRef.numParts() - 1)) {
// Creates the array element
mb::Document& doc = _preparedState->doc;
StringData lastPart = _fieldRef.getPart(_fieldRef.numParts() - 1);
mb::Element baseArray = doc.makeElementArray(lastPart);
if (!baseArray.ok()) {
return Status(ErrorCodes::InternalError, "can't create new base array");
}
// 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.
Status status = pathsupport::createPathAt(
_fieldRef, _preparedState->idxFound, _preparedState->elemFound, baseArray);
if (!status.isOK()) {
return status;
}
// Point to the base array just created. The subsequent code expects it to exist
// already.
_preparedState->elemFound = baseArray;
}
if (_preparedState->addAll) {
// If we are adding all the values, we can just walk over _val;
mb::Element where = _val.leftChild();
while (where.ok()) {
dassert(where.hasValue());
mb::Element toAdd = _preparedState->doc.makeElement(where.getValue());
Status status = _preparedState->elemFound.pushBack(toAdd);
if (!status.isOK())
return status;
where = where.rightSibling();
}
} else {
// Otherwise, we aren't adding all the values, and we need to add exactly those
// elements that were found to be missing during our scan in prepare.
std::vector<mb::Element>::const_iterator where = _preparedState->elementsToAdd.begin();
const std::vector<mb::Element>::const_iterator end = _preparedState->elementsToAdd.end();
for (; where != end; ++where) {
dassert(where->hasValue());
mb::Element toAdd = _preparedState->doc.makeElement(where->getValue());
Status status = _preparedState->elemFound.pushBack(toAdd);
if (!status.isOK())
return status;
}
}
return Status::OK();
}
Status ModifierAddToSet::log(LogBuilder* logBuilder) const {
// TODO: This is copied more or less identically from $push. As a result, it copies the
// behavior in $push that relies on 'apply' having been called unless this is a no-op.
// TODO We can log just a positional set in several cases. For now, let's just log the
// full resulting array.
// We'd like to create an entry such as {$set: {<fieldname>: [<resulting aray>]}} under
// 'logRoot'. We start by creating the {$set: ...} Element.
mb::Document& doc = logBuilder->getDocument();
// Then we create the {<fieldname>:[]} Element, that is, an empty array.
mb::Element logElement = doc.makeElementArray(_fieldRef.dottedField());
if (!logElement.ok()) {
return Status(ErrorCodes::InternalError, "cannot create details for $addToSet mod");
}
// Fill up the empty array.
mb::Element curr = _preparedState->elemFound.leftChild();
while (curr.ok()) {
dassert(curr.hasValue());
// We need to copy each array entry from the resulting document to the log
// document.
mb::Element currCopy = doc.makeElementWithNewFieldName(StringData(), curr.getValue());
if (!currCopy.ok()) {
return Status(ErrorCodes::InternalError, "could create copy element");
}
Status status = logElement.pushBack(currCopy);
if (!status.isOK()) {
return Status(ErrorCodes::BadValue,
str::stream() << "Could not append entry for $addToSet oplog entry."
<< "Underlying cause: "
<< status.toString());
}
curr = curr.rightSibling();
}
return logBuilder->addToSets(logElement);
}
} // namespace mongo
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