/**
* 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 .
*
* 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_object_replace.h"
#include "mongo/base/data_view.h"
#include "mongo/base/error_codes.h"
#include "mongo/bson/mutable/document.h"
#include "mongo/db/global_timestamp.h"
#include "mongo/db/ops/log_builder.h"
#include "mongo/util/mongoutils/str.h"
namespace mongo {
namespace str = mongoutils::str;
namespace {
const char idFieldName[] = "_id";
Status fixupTimestamps(const BSONObj& obj) {
BSONObjIterator i(obj);
while (i.more()) {
BSONElement e = i.next();
// Skip _id field -- we do not replace it
if (e.type() == bsonTimestamp && e.fieldNameStringData() != idFieldName) {
auto timestampView = DataView(const_cast(e.value()));
// We don't need to do an endian-safe read here, because 0 is 0 either way.
unsigned long long timestamp = timestampView.read();
if (timestamp == 0) {
// performance note, this locks a mutex:
Timestamp ts(getNextGlobalTimestamp());
timestampView.write(tagLittleEndian(ts.asULL()));
}
}
}
return Status::OK();
}
}
struct ModifierObjectReplace::PreparedState {
PreparedState(mutablebson::Document* targetDoc) : doc(*targetDoc), noOp(false) {}
// Document that is going to be changed
mutablebson::Document& doc;
// This is a no op
bool noOp;
};
ModifierObjectReplace::ModifierObjectReplace() : _val() {}
ModifierObjectReplace::~ModifierObjectReplace() {}
Status ModifierObjectReplace::init(const BSONElement& modExpr,
const Options& opts,
bool* positional) {
if (modExpr.type() != Object) {
// Impossible, really since the caller check this already...
return Status(ErrorCodes::BadValue,
str::stream() << "Document replacement expects a complete document"
" but the type supplied was "
<< modExpr.type());
}
// Object replacements never have positional operator.
if (positional)
*positional = false;
// We make a copy of the object here because the update driver does not guarantees, in
// the case of object replacement, that the modExpr is going to outlive this mod.
_val = modExpr.embeddedObject().getOwned();
return fixupTimestamps(_val);
}
Status ModifierObjectReplace::prepare(mutablebson::Element root,
StringData matchedField,
ExecInfo* execInfo) {
_preparedState.reset(new PreparedState(&root.getDocument()));
// objectSize checked by binaryEqual (optimization)
BSONObj objOld = root.getDocument().getObject();
if (objOld.binaryEqual(_val)) {
_preparedState->noOp = true;
execInfo->noOp = true;
}
return Status::OK();
}
Status ModifierObjectReplace::apply() const {
dassert(!_preparedState->noOp);
// Remove the contents of the provided doc.
mutablebson::Document& doc = _preparedState->doc;
mutablebson::Element current = doc.root().leftChild();
mutablebson::Element srcIdElement = doc.end();
while (current.ok()) {
mutablebson::Element toRemove = current;
current = current.rightSibling();
// Skip _id field element -- it should not change
if (toRemove.getFieldName() == idFieldName) {
srcIdElement = toRemove;
continue;
}
Status status = toRemove.remove();
if (!status.isOK()) {
return status;
}
}
// Insert the provided contents instead.
BSONElement dstIdElement;
BSONObjIterator it(_val);
while (it.more()) {
BSONElement elem = it.next();
if (elem.fieldNameStringData() == idFieldName) {
dstIdElement = elem;
// Do not duplicate _id field
if (srcIdElement.ok()) {
if (srcIdElement.compareWithBSONElement(dstIdElement, true) != 0) {
return Status(ErrorCodes::ImmutableField,
str::stream() << "The _id field cannot be changed from {"
<< srcIdElement.toString()
<< "} to {"
<< dstIdElement.toString()
<< "}.");
}
continue;
}
}
Status status = doc.root().appendElement(elem);
if (!status.isOK()) {
return status;
}
}
return Status::OK();
}
Status ModifierObjectReplace::log(LogBuilder* logBuilder) const {
mutablebson::Document& doc = logBuilder->getDocument();
mutablebson::Element replacementObject = doc.end();
Status status = logBuilder->getReplacementObject(&replacementObject);
if (status.isOK()) {
mutablebson::Element current = _preparedState->doc.root().leftChild();
while (current.ok()) {
status = replacementObject.appendElement(current.getValue());
if (!status.isOK())
return status;
current = current.rightSibling();
}
}
return status;
}
} // namespace mongo