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/**
* Copyright (C) 2011 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/platform/basic.h"
#include <cctype>
#include "mongo/db/jsobj.h"
#include "mongo/db/matcher/extensions_callback_noop.h"
#include "mongo/db/matcher/matcher.h"
#include "mongo/db/pipeline/document.h"
#include "mongo/db/pipeline/document_source.h"
#include "mongo/db/pipeline/expression.h"
#include "mongo/util/stringutils.h"
namespace mongo {
using boost::intrusive_ptr;
using std::string;
using std::vector;
REGISTER_DOCUMENT_SOURCE(match, DocumentSourceMatch::createFromBson);
const char* DocumentSourceMatch::getSourceName() const {
return "$match";
}
Value DocumentSourceMatch::serialize(bool explain) const {
return Value(DOC(getSourceName() << Document(getQuery())));
}
intrusive_ptr<DocumentSource> DocumentSourceMatch::optimize() {
return getQuery().isEmpty() ? nullptr : this;
}
boost::optional<Document> DocumentSourceMatch::getNext() {
pExpCtx->checkForInterrupt();
// The user facing error should have been generated earlier.
massert(17309, "Should never call getNext on a $match stage with $text clause", !_isTextQuery);
while (boost::optional<Document> next = pSource->getNext()) {
// The matcher only takes BSON documents, so we have to make one.
if (matcher->matches(next->toBson()))
return next;
}
// Nothing matched
return boost::none;
}
bool DocumentSourceMatch::coalesce(const intrusive_ptr<DocumentSource>& nextSource) {
DocumentSourceMatch* otherMatch = dynamic_cast<DocumentSourceMatch*>(nextSource.get());
if (!otherMatch)
return false;
if (otherMatch->_isTextQuery) {
// Non-initial text queries are disallowed (enforced by setSource below). This prevents
// "hiding" a non-initial text query by combining it with another match.
return false;
// The rest of this block is for once we support non-initial text queries.
if (_isTextQuery) {
// The score should only come from the last $match. We can't combine since then this
// match's score would impact otherMatch's.
return false;
}
_isTextQuery = true;
}
// Replace our matcher with the $and of ours and theirs.
matcher.reset(new Matcher(BSON("$and" << BSON_ARRAY(getQuery() << otherMatch->getQuery())),
ExtensionsCallbackNoop()));
return true;
}
namespace {
// This block contains the functions that make up the implementation of
// DocumentSourceMatch::redactSafePortion(). They will only be called after
// the Match expression has been successfully parsed so they can assume that
// input is well formed.
bool isAllDigits(StringData str) {
if (str.empty())
return false;
for (size_t i = 0; i < str.size(); i++) {
if (!isdigit(str[i]))
return false;
}
return true;
}
bool isFieldnameRedactSafe(StringData fieldName) {
// Can't have numeric elements in the dotted path since redacting elements from an array
// would change the indexes.
const size_t dotPos = fieldName.find('.');
if (dotPos == string::npos)
return !isAllDigits(fieldName);
const StringData part = fieldName.substr(0, dotPos);
const StringData rest = fieldName.substr(dotPos + 1);
return !isAllDigits(part) && isFieldnameRedactSafe(rest);
}
bool isTypeRedactSafeInComparison(BSONType type) {
if (type == Array)
return false;
if (type == Object)
return false;
if (type == jstNULL)
return false;
if (type == Undefined)
return false; // Currently a Matcher parse error.
return true;
}
Document redactSafePortionTopLevel(BSONObj query); // mutually recursive with next function
// Returns the redact-safe portion of an "inner" match expression. This is the layer like
// {$gt: 5} which does not include the field name. Returns an empty document if none of the
// expression can safely be promoted in front of a $redact.
Document redactSafePortionDollarOps(BSONObj expr) {
MutableDocument output;
BSONForEach(field, expr) {
if (field.fieldName()[0] != '$')
continue;
switch (BSONObj::MatchType(field.getGtLtOp(BSONObj::Equality))) {
// These are always ok
case BSONObj::opTYPE:
case BSONObj::opREGEX:
case BSONObj::opOPTIONS:
case BSONObj::opMOD:
case BSONObj::opBITS_ALL_SET:
case BSONObj::opBITS_ALL_CLEAR:
case BSONObj::opBITS_ANY_SET:
case BSONObj::opBITS_ANY_CLEAR:
output[field.fieldNameStringData()] = Value(field);
break;
// These are ok if the type of the rhs is allowed in comparisons
case BSONObj::LTE:
case BSONObj::GTE:
case BSONObj::LT:
case BSONObj::GT:
if (isTypeRedactSafeInComparison(field.type()))
output[field.fieldNameStringData()] = Value(field);
break;
// $in must be all-or-nothing (like $or). Can't include subset of elements.
case BSONObj::opIN: {
bool allOk = true;
BSONForEach(elem, field.Obj()) {
if (!isTypeRedactSafeInComparison(elem.type())) {
allOk = false;
break;
}
}
if (allOk) {
output[field.fieldNameStringData()] = Value(field);
}
break;
}
case BSONObj::opALL: {
// $all can include subset of elements (like $and).
vector<Value> matches;
BSONForEach(elem, field.Obj()) {
// NOTE this currently doesn't allow {$all: [{$elemMatch: {...}}]}
if (isTypeRedactSafeInComparison(elem.type())) {
matches.push_back(Value(elem));
}
}
if (!matches.empty())
output[field.fieldNameStringData()] = Value(std::move(matches));
break;
}
case BSONObj::opELEM_MATCH: {
BSONObj subIn = field.Obj();
Document subOut;
if (subIn.firstElementFieldName()[0] == '$') {
subOut = redactSafePortionDollarOps(subIn);
} else {
subOut = redactSafePortionTopLevel(subIn);
}
if (!subOut.empty())
output[field.fieldNameStringData()] = Value(subOut);
break;
}
// These are never allowed
case BSONObj::Equality: // This actually means unknown
case BSONObj::opNEAR:
case BSONObj::NE:
case BSONObj::opSIZE:
case BSONObj::NIN:
case BSONObj::opEXISTS:
case BSONObj::opWITHIN:
case BSONObj::opGEO_INTERSECTS:
continue;
}
}
return output.freeze();
}
// Returns the redact-safe portion of an "outer" match expression. This is the layer like
// {fieldName: {...}} which does include the field name. Returns an empty document if none of
// the expression can safely be promoted in front of a $redact.
Document redactSafePortionTopLevel(BSONObj query) {
MutableDocument output;
BSONForEach(field, query) {
if (field.fieldName()[0] == '$') {
if (str::equals(field.fieldName(), "$or")) {
// $or must be all-or-nothing (line $in). Can't include subset of elements.
vector<Value> okClauses;
BSONForEach(elem, field.Obj()) {
Document clause = redactSafePortionTopLevel(elem.Obj());
if (clause.empty()) {
okClauses.clear();
break;
}
okClauses.push_back(Value(clause));
}
if (!okClauses.empty())
output["$or"] = Value(std::move(okClauses));
} else if (str::equals(field.fieldName(), "$and")) {
// $and can include subset of elements (like $all).
vector<Value> okClauses;
BSONForEach(elem, field.Obj()) {
Document clause = redactSafePortionTopLevel(elem.Obj());
if (!clause.empty())
okClauses.push_back(Value(clause));
}
if (!okClauses.empty())
output["$and"] = Value(std::move(okClauses));
}
continue;
}
if (!isFieldnameRedactSafe(field.fieldNameStringData()))
continue;
switch (field.type()) {
case Array:
continue; // exact matches on arrays are never allowed
case jstNULL:
continue; // can't look for missing fields
case Undefined:
continue; // Currently a Matcher parse error.
case Object: {
Document sub = redactSafePortionDollarOps(field.Obj());
if (!sub.empty())
output[field.fieldNameStringData()] = Value(sub);
break;
}
// All other types are ok to pass through
default:
output[field.fieldNameStringData()] = Value(field);
break;
}
}
return output.freeze();
}
}
BSONObj DocumentSourceMatch::redactSafePortion() const {
return redactSafePortionTopLevel(getQuery()).toBson();
}
void DocumentSourceMatch::setSource(DocumentSource* source) {
uassert(17313, "$match with $text is only allowed as the first pipeline stage", !_isTextQuery);
DocumentSource::setSource(source);
}
bool DocumentSourceMatch::isTextQuery(const BSONObj& query) {
BSONForEach(e, query) {
const StringData fieldName = e.fieldNameStringData();
if (fieldName == StringData("$text", StringData::LiteralTag()))
return true;
if (e.isABSONObj() && isTextQuery(e.Obj()))
return true;
}
return false;
}
static void uassertNoDisallowedClauses(BSONObj query) {
BSONForEach(e, query) {
// can't use the Matcher API because this would segfault the constructor
uassert(16395,
"$where is not allowed inside of a $match aggregation expression",
!str::equals(e.fieldName(), "$where"));
// geo breaks if it is not the first portion of the pipeline
uassert(16424,
"$near is not allowed inside of a $match aggregation expression",
!str::equals(e.fieldName(), "$near"));
uassert(16426,
"$nearSphere is not allowed inside of a $match aggregation expression",
!str::equals(e.fieldName(), "$nearSphere"));
if (e.isABSONObj())
uassertNoDisallowedClauses(e.Obj());
}
}
intrusive_ptr<DocumentSource> DocumentSourceMatch::createFromBson(
BSONElement elem, const intrusive_ptr<ExpressionContext>& pExpCtx) {
uassert(15959, "the match filter must be an expression in an object", elem.type() == Object);
uassertNoDisallowedClauses(elem.Obj());
return new DocumentSourceMatch(elem.Obj(), pExpCtx);
}
BSONObj DocumentSourceMatch::getQuery() const {
return *(matcher->getQuery());
}
DocumentSourceMatch::DocumentSourceMatch(const BSONObj& query,
const intrusive_ptr<ExpressionContext>& pExpCtx)
: DocumentSource(pExpCtx),
matcher(new Matcher(query.getOwned(), ExtensionsCallbackNoop())),
_isTextQuery(isTextQuery(query)) {}
}
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