SERVER-19510 Move ExtensionsCallback out of MatchExpressionParser

21 files changed, 257 insertions, 201 deletions

diff --git a/src/mongo/db/auth/authz_manager_external_state_mock.cpp b/src/mongo/db/auth/authz_manager_external_state_mock.cpp
index 797d6a147ea..94617a82fbe 100644
--- a/src/mongo/db/auth/authz_manager_external_state_mock.cpp
+++ b/src/mongo/db/auth/authz_manager_external_state_mock.cpp
@@ -274,7 +274,7 @@ Status AuthzManagerExternalStateMock::_queryVector(
     const BSONObj& query,
     std::vector<BSONObjCollection::iterator>* result) {
     StatusWithMatchExpression parseResult =
-        MatchExpressionParser::parse(query, MatchExpressionParser::ExtensionsCallback());
+        MatchExpressionParser::parse(query, ExtensionsCallback());
     if (!parseResult.isOK()) {
         return parseResult.getStatus();
     }
diff --git a/src/mongo/db/exec/projection.h b/src/mongo/db/exec/projection.h
index 87a3f97a2fd..aa03665bd3a 100644
--- a/src/mongo/db/exec/projection.h
+++ b/src/mongo/db/exec/projection.h
@@ -37,6 +37,8 @@
 
 namespace mongo {
 
+class ExtensionsCallback;
+
 struct ProjectionStageParams {
     enum ProjectionImplementation {
         // The default case.  Will handle every projection.
@@ -49,7 +51,7 @@ struct ProjectionStageParams {
         SIMPLE_DOC
     };
 
-    ProjectionStageParams(const MatchExpressionParser::ExtensionsCallback& wc)
+    ProjectionStageParams(const ExtensionsCallback& wc)
         : projImpl(NO_FAST_PATH), fullExpression(NULL), extensionsCallback(&wc) {}
 
     ProjectionImplementation projImpl;
@@ -67,7 +69,7 @@ struct ProjectionStageParams {
     BSONObj coveredKeyObj;
 
     // Used for creating context for the match extensions processing. Not owned.
-    const MatchExpressionParser::ExtensionsCallback* extensionsCallback;
+    const ExtensionsCallback* extensionsCallback;
 };
 
 /**
diff --git a/src/mongo/db/exec/projection_exec.cpp b/src/mongo/db/exec/projection_exec.cpp
index d0eb29d1827..f5ea2cfd901 100644
--- a/src/mongo/db/exec/projection_exec.cpp
+++ b/src/mongo/db/exec/projection_exec.cpp
@@ -74,7 +74,7 @@ ProjectionExec::ProjectionExec()
 
 ProjectionExec::ProjectionExec(const BSONObj& spec,
                                const MatchExpression* queryExpression,
-                               const MatchExpressionParser::ExtensionsCallback& extensionsCallback)
+                               const ExtensionsCallback& extensionsCallback)
     : _include(true),
       _special(false),
       _source(spec),
diff --git a/src/mongo/db/exec/projection_exec.h b/src/mongo/db/exec/projection_exec.h
index 9be352118d3..6558b75fbf3 100644
--- a/src/mongo/db/exec/projection_exec.h
+++ b/src/mongo/db/exec/projection_exec.h
@@ -66,8 +66,7 @@ public:
 
     ProjectionExec(const BSONObj& spec,
                    const MatchExpression* queryExpression,
-                   const MatchExpressionParser::ExtensionsCallback& extensionsCallback =
-                       MatchExpressionParser::ExtensionsCallback());
+                   const ExtensionsCallback& extensionsCallback = ExtensionsCallback());
     ~ProjectionExec();
 
     /**
diff --git a/src/mongo/db/matcher/SConscript b/src/mongo/db/matcher/SConscript
index 506e2ba1cbc..af686b9f96b 100644
--- a/src/mongo/db/matcher/SConscript
+++ b/src/mongo/db/matcher/SConscript
@@ -37,6 +37,7 @@ env.Library(
         'expression_tree.cpp',
         'expression_where_base.cpp',
         'expression_where_noop.cpp',
+        'extensions_callback.cpp',
         'extensions_callback_noop.cpp',
         'match_details.cpp',
         'matchable.cpp',
diff --git a/src/mongo/db/matcher/expression.h b/src/mongo/db/matcher/expression.h
index 52f026d589e..0a67870d4ff 100644
--- a/src/mongo/db/matcher/expression.h
+++ b/src/mongo/db/matcher/expression.h
@@ -41,8 +41,11 @@
 
 namespace mongo {
 
+class MatchExpression;
 class TreeMatchExpression;
 
+typedef StatusWith<std::unique_ptr<MatchExpression>> StatusWithMatchExpression;
+
 class MatchExpression {
     MONGO_DISALLOW_COPYING(MatchExpression);
 
diff --git a/src/mongo/db/matcher/expression_parser.cpp b/src/mongo/db/matcher/expression_parser.cpp
index 6692e41aead..0c385c78d69 100644
--- a/src/mongo/db/matcher/expression_parser.cpp
+++ b/src/mongo/db/matcher/expression_parser.cpp
@@ -33,7 +33,6 @@
 #include "mongo/bson/bsonmisc.h"
 #include "mongo/bson/bsonobj.h"
 #include "mongo/bson/bsonobjbuilder.h"
-#include "mongo/bson/util/bson_extract.h"
 #include "mongo/db/matcher/expression_array.h"
 #include "mongo/db/matcher/expression_leaf.h"
 #include "mongo/db/matcher/expression_tree.h"
@@ -953,103 +952,6 @@ StatusWith<std::vector<uint32_t>> MatchExpressionParser::_parseBitPositionsArray
     return bitPositions;
 }
 
-StatusWithMatchExpression MatchExpressionParser::ExtensionsCallback::parseWhere(
-    BSONElement where) const {
-    return {Status(ErrorCodes::NoMatchParseContext, "no context for parsing $where")};
-}
-
-StatusWithMatchExpression MatchExpressionParser::ExtensionsCallback::parseText(
-    BSONElement text) const {
-    return {Status(ErrorCodes::NoMatchParseContext, "no context for parsing $text")};
-}
-
-StatusWith<WhereMatchExpressionBase::WhereParams>
-MatchExpressionParser::ExtensionsCallback::extractWhereMatchExpressionParams(BSONElement where) {
-    WhereMatchExpressionBase::WhereParams params;
-
-    switch (where.type()) {
-        case mongo::String:
-        case mongo::Code:
-            params.code = where._asCode();
-            params.scope = BSONObj();
-            break;
-        case mongo::CodeWScope:
-            params.code = where._asCode();
-            params.scope = where.codeWScopeObject().getOwned();
-            break;
-        default:
-            return {ErrorCodes::BadValue, "$where got bad type"};
-    }
-
-    if (params.code.empty()) {
-        return {ErrorCodes::BadValue, "code for $where cannot be empty"};
-    }
-
-    return params;
-}
-
-StatusWith<TextMatchExpressionBase::TextParams>
-MatchExpressionParser::ExtensionsCallback::extractTextMatchExpressionParams(BSONElement text) {
-    TextMatchExpressionBase::TextParams params;
-    if (text.type() != Object) {
-        return {ErrorCodes::BadValue, "$text expects an object"};
-    }
-    BSONObj queryObj = text.Obj();
-
-    //
-    // Parse required fields.
-    //
-
-    Status queryStatus = bsonExtractStringField(queryObj, "$search", &params.query);
-    if (!queryStatus.isOK()) {
-        return queryStatus;
-    }
-
-    //
-    // Parse optional fields.
-    //
-
-    int expectedFieldCount = 1;
-
-    Status languageStatus = bsonExtractStringField(queryObj, "$language", &params.language);
-    if (languageStatus == ErrorCodes::TypeMismatch) {
-        return languageStatus;
-    } else if (languageStatus == ErrorCodes::NoSuchKey) {
-        params.language = string();
-    } else {
-        invariantOK(languageStatus);
-        expectedFieldCount++;
-    }
-
-    Status caseSensitiveStatus =
-        bsonExtractBooleanField(queryObj, "$caseSensitive", &params.caseSensitive);
-    if (caseSensitiveStatus == ErrorCodes::TypeMismatch) {
-        return caseSensitiveStatus;
-    } else if (caseSensitiveStatus == ErrorCodes::NoSuchKey) {
-        params.caseSensitive = TextMatchExpressionBase::kCaseSensitiveDefault;
-    } else {
-        invariantOK(caseSensitiveStatus);
-        expectedFieldCount++;
-    }
-
-    Status diacriticSensitiveStatus =
-        bsonExtractBooleanField(queryObj, "$diacriticSensitive", &params.diacriticSensitive);
-    if (diacriticSensitiveStatus == ErrorCodes::TypeMismatch) {
-        return diacriticSensitiveStatus;
-    } else if (diacriticSensitiveStatus == ErrorCodes::NoSuchKey) {
-        params.diacriticSensitive = TextMatchExpressionBase::kDiacriticSensitiveDefault;
-    } else {
-        invariantOK(diacriticSensitiveStatus);
-        expectedFieldCount++;
-    }
-
-    if (queryObj.nFields() != expectedFieldCount) {
-        return {ErrorCodes::BadValue, "extra fields in $text"};
-    }
-
-    return {std::move(params)};
-}
-
 // Geo
 StatusWithMatchExpression expressionParserGeoCallbackDefault(const char* name,
                                                              int type,
diff --git a/src/mongo/db/matcher/expression_parser.h b/src/mongo/db/matcher/expression_parser.h
index 5af324291da..465928ab184 100644
--- a/src/mongo/db/matcher/expression_parser.h
+++ b/src/mongo/db/matcher/expression_parser.h
@@ -35,50 +35,16 @@
 #include "mongo/db/matcher/expression.h"
 #include "mongo/db/matcher/expression_leaf.h"
 #include "mongo/db/matcher/expression_tree.h"
-#include "mongo/db/matcher/expression_text_base.h"
-#include "mongo/db/matcher/expression_where_base.h"
+#include "mongo/db/matcher/extensions_callback.h"
 #include "mongo/stdx/functional.h"
 
 namespace mongo {
 
 class OperationContext;
 
-typedef StatusWith<std::unique_ptr<MatchExpression>> StatusWithMatchExpression;
-
 class MatchExpressionParser {
 public:
     /**
-     * Certain match clauses (the "extension" clauses, namely $text and $where) require context in
-     * order to perform parsing. This context is captured inside of an ExtensionsCallback object.
-     *
-     * The default implementations of parseText() and parseWhere() simply return an error Status.
-     * Instead of constructing an ExtensionsCallback object directly, an instance of one of the
-     * derived classes (ExtensionsCallbackReal or ExtensionsCallbackNoop) should generally be used
-     * instead.
-     */
-    class ExtensionsCallback {
-    public:
-        virtual StatusWithMatchExpression parseText(BSONElement text) const;
-
-        virtual StatusWithMatchExpression parseWhere(BSONElement where) const;
-
-        virtual ~ExtensionsCallback() {}
-
-    protected:
-        /**
-         * Helper method which extracts parameters from the given $text element.
-         */
-        static StatusWith<TextMatchExpressionBase::TextParams> extractTextMatchExpressionParams(
-            BSONElement text);
-
-        /**
-         * Helper method which extracts parameters from the given $where element.
-         */
-        static StatusWith<WhereMatchExpressionBase::WhereParams> extractWhereMatchExpressionParams(
-            BSONElement where);
-    };
-
-    /**
      * caller has to maintain ownership obj
      * the tree has views (BSONElement) into obj
      */
diff --git a/src/mongo/db/matcher/extensions_callback.cpp b/src/mongo/db/matcher/extensions_callback.cpp
new file mode 100644
index 00000000000..a2fd775865b
--- /dev/null
+++ b/src/mongo/db/matcher/extensions_callback.cpp
@@ -0,0 +1,132 @@
+/**
+ *    Copyright (C) 2015 MongoDB 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 "mongo/db/matcher/extensions_callback.h"
+
+#include "mongo/bson/util/bson_extract.h"
+
+namespace mongo {
+
+StatusWithMatchExpression ExtensionsCallback::parseWhere(BSONElement where) const {
+    return {Status(ErrorCodes::NoMatchParseContext, "no context for parsing $where")};
+}
+
+StatusWithMatchExpression ExtensionsCallback::parseText(BSONElement text) const {
+    return {Status(ErrorCodes::NoMatchParseContext, "no context for parsing $text")};
+}
+
+StatusWith<TextMatchExpressionBase::TextParams>
+ExtensionsCallback::extractTextMatchExpressionParams(BSONElement text) {
+    TextMatchExpressionBase::TextParams params;
+    if (text.type() != Object) {
+        return {ErrorCodes::BadValue, "$text expects an object"};
+    }
+    BSONObj queryObj = text.Obj();
+
+    //
+    // Parse required fields.
+    //
+
+    Status queryStatus = bsonExtractStringField(queryObj, "$search", &params.query);
+    if (!queryStatus.isOK()) {
+        return queryStatus;
+    }
+
+    //
+    // Parse optional fields.
+    //
+
+    int expectedFieldCount = 1;
+
+    Status languageStatus = bsonExtractStringField(queryObj, "$language", &params.language);
+    if (languageStatus == ErrorCodes::TypeMismatch) {
+        return languageStatus;
+    } else if (languageStatus == ErrorCodes::NoSuchKey) {
+        params.language = std::string();
+    } else {
+        invariantOK(languageStatus);
+        expectedFieldCount++;
+    }
+
+    Status caseSensitiveStatus =
+        bsonExtractBooleanField(queryObj, "$caseSensitive", &params.caseSensitive);
+    if (caseSensitiveStatus == ErrorCodes::TypeMismatch) {
+        return caseSensitiveStatus;
+    } else if (caseSensitiveStatus == ErrorCodes::NoSuchKey) {
+        params.caseSensitive = TextMatchExpressionBase::kCaseSensitiveDefault;
+    } else {
+        invariantOK(caseSensitiveStatus);
+        expectedFieldCount++;
+    }
+
+    Status diacriticSensitiveStatus =
+        bsonExtractBooleanField(queryObj, "$diacriticSensitive", &params.diacriticSensitive);
+    if (diacriticSensitiveStatus == ErrorCodes::TypeMismatch) {
+        return diacriticSensitiveStatus;
+    } else if (diacriticSensitiveStatus == ErrorCodes::NoSuchKey) {
+        params.diacriticSensitive = TextMatchExpressionBase::kDiacriticSensitiveDefault;
+    } else {
+        invariantOK(diacriticSensitiveStatus);
+        expectedFieldCount++;
+    }
+
+    if (queryObj.nFields() != expectedFieldCount) {
+        return {ErrorCodes::BadValue, "extra fields in $text"};
+    }
+
+    return {std::move(params)};
+}
+
+StatusWith<WhereMatchExpressionBase::WhereParams>
+ExtensionsCallback::extractWhereMatchExpressionParams(BSONElement where) {
+    WhereMatchExpressionBase::WhereParams params;
+
+    switch (where.type()) {
+        case mongo::String:
+        case mongo::Code:
+            params.code = where._asCode();
+            params.scope = BSONObj();
+            break;
+        case mongo::CodeWScope:
+            params.code = where._asCode();
+            params.scope = where.codeWScopeObject().getOwned();
+            break;
+        default:
+            return {ErrorCodes::BadValue, "$where got bad type"};
+    }
+
+    if (params.code.empty()) {
+        return {ErrorCodes::BadValue, "code for $where cannot be empty"};
+    }
+
+    return params;
+}
+
+}  // namespace mongo
diff --git a/src/mongo/db/matcher/extensions_callback.h b/src/mongo/db/matcher/extensions_callback.h
new file mode 100644
index 00000000000..869d90ef8f3
--- /dev/null
+++ b/src/mongo/db/matcher/extensions_callback.h
@@ -0,0 +1,68 @@
+/**
+ *    Copyright (C) 2015 MongoDB 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.
+ */
+
+#pragma once
+
+#include "mongo/db/matcher/expression.h"
+#include "mongo/db/matcher/expression_text_base.h"
+#include "mongo/db/matcher/expression_where_base.h"
+
+namespace mongo {
+
+/**
+ * Certain match clauses (the "extension" clauses, namely $text and $where) require context in
+ * order to perform parsing. This context is captured inside of an ExtensionsCallback object.
+ *
+ * The default implementations of parseText() and parseWhere() simply return an error Status.
+ * Instead of constructing an ExtensionsCallback object directly, an instance of one of the
+ * derived classes (ExtensionsCallbackReal or ExtensionsCallbackNoop) should generally be used
+ * instead.
+ */
+class ExtensionsCallback {
+public:
+    virtual StatusWithMatchExpression parseText(BSONElement text) const;
+
+    virtual StatusWithMatchExpression parseWhere(BSONElement where) const;
+
+    virtual ~ExtensionsCallback() {}
+
+protected:
+    /**
+     * Helper method which extracts parameters from the given $text element.
+     */
+    static StatusWith<TextMatchExpressionBase::TextParams> extractTextMatchExpressionParams(
+        BSONElement text);
+
+    /**
+     * Helper method which extracts parameters from the given $where element.
+     */
+    static StatusWith<WhereMatchExpressionBase::WhereParams> extractWhereMatchExpressionParams(
+        BSONElement where);
+};
+
+}  // namespace mongo
diff --git a/src/mongo/db/matcher/extensions_callback_noop.h b/src/mongo/db/matcher/extensions_callback_noop.h
index b66955add43..127e1d422a6 100644
--- a/src/mongo/db/matcher/extensions_callback_noop.h
+++ b/src/mongo/db/matcher/extensions_callback_noop.h
@@ -28,7 +28,7 @@
 
 #pragma once
 
-#include "mongo/db/matcher/expression_parser.h"
+#include "mongo/db/matcher/extensions_callback.h"
 
 namespace mongo {
 
@@ -37,7 +37,7 @@ namespace mongo {
  * be used for matching.  It should be used when parsing context is not available (for example, when
  * the relevant namespace does not exist, or in mongos).
  */
-class ExtensionsCallbackNoop : public MatchExpressionParser::ExtensionsCallback {
+class ExtensionsCallbackNoop : public ExtensionsCallback {
 public:
     /**
      * Returns a TextNoOpMatchExpression, or an error Status if parsing fails.
diff --git a/src/mongo/db/matcher/extensions_callback_real.h b/src/mongo/db/matcher/extensions_callback_real.h
index 6d4caf5c286..45b97e4b9c3 100644
--- a/src/mongo/db/matcher/extensions_callback_real.h
+++ b/src/mongo/db/matcher/extensions_callback_real.h
@@ -28,17 +28,18 @@
 
 #pragma once
 
-#include "mongo/db/matcher/expression_parser.h"
+#include "mongo/db/matcher/extensions_callback.h"
 
 namespace mongo {
 
 class NamespaceString;
+class OperationContext;
 
 /**
  * ExtensionsCallbackReal uses the provided OperationContext and namespace to capture context
  * necessary for parsing $text and $where clauses.
  */
-class ExtensionsCallbackReal : public MatchExpressionParser::ExtensionsCallback {
+class ExtensionsCallbackReal : public ExtensionsCallback {
 public:
     /**
      * Does not take ownership of 'nss' or 'txn'.
diff --git a/src/mongo/db/matcher/matcher.cpp b/src/mongo/db/matcher/matcher.cpp
index 1275a5c4408..c0ed2bf6985 100644
--- a/src/mongo/db/matcher/matcher.cpp
+++ b/src/mongo/db/matcher/matcher.cpp
@@ -41,8 +41,7 @@
 
 namespace mongo {
 
-Matcher::Matcher(const BSONObj& pattern,
-                 const MatchExpressionParser::ExtensionsCallback& extensionsCallback)
+Matcher::Matcher(const BSONObj& pattern, const ExtensionsCallback& extensionsCallback)
     : _pattern(pattern) {
     StatusWithMatchExpression statusWithMatcher =
         MatchExpressionParser::parse(pattern, extensionsCallback);
diff --git a/src/mongo/db/matcher/matcher.h b/src/mongo/db/matcher/matcher.h
index c1369c154cf..e49602804a2 100644
--- a/src/mongo/db/matcher/matcher.h
+++ b/src/mongo/db/matcher/matcher.h
@@ -49,8 +49,7 @@ class Matcher {
 
 public:
     explicit Matcher(const BSONObj& pattern,
-                     const MatchExpressionParser::ExtensionsCallback& extensionsCallback =
-                         MatchExpressionParser::ExtensionsCallback());
+                     const ExtensionsCallback& extensionsCallback = ExtensionsCallback());
 
     bool matches(const BSONObj& doc, MatchDetails* details = NULL) const;
 
diff --git a/src/mongo/db/ops/modifier_pull.cpp b/src/mongo/db/ops/modifier_pull.cpp
index 530ecfffb5e..ac7e5c41e8c 100644
--- a/src/mongo/db/ops/modifier_pull.cpp
+++ b/src/mongo/db/ops/modifier_pull.cpp
@@ -118,7 +118,7 @@ Status ModifierPull::init(const BSONElement& modExpr, const Options& opts, bool*
         // Build the matcher around the object we built above. Currently, we do not allow $pull
         // operations to contain $text/$where clauses, so preserving this behaviour.
         StatusWithMatchExpression parseResult =
-            MatchExpressionParser::parse(_exprObj, MatchExpressionParser::ExtensionsCallback());
+            MatchExpressionParser::parse(_exprObj, ExtensionsCallback());
         if (!parseResult.isOK()) {
             return parseResult.getStatus();
         }
diff --git a/src/mongo/db/query/canonical_query.cpp b/src/mongo/db/query/canonical_query.cpp
index 12fdd177746..ed22674e0db 100644
--- a/src/mongo/db/query/canonical_query.cpp
+++ b/src/mongo/db/query/canonical_query.cpp
@@ -102,9 +102,7 @@ bool matchExpressionLessThan(const MatchExpression* lhs, const MatchExpression*
 
 // static
 StatusWith<std::unique_ptr<CanonicalQuery>> CanonicalQuery::canonicalize(
-    NamespaceString nss,
-    const BSONObj& query,
-    const MatchExpressionParser::ExtensionsCallback& extensionsCallback) {
+    NamespaceString nss, const BSONObj& query, const ExtensionsCallback& extensionsCallback) {
     const BSONObj emptyObj;
     return CanonicalQuery::canonicalize(
         std::move(nss), query, emptyObj, emptyObj, 0, 0, extensionsCallback);
@@ -115,7 +113,7 @@ StatusWith<std::unique_ptr<CanonicalQuery>> CanonicalQuery::canonicalize(
     NamespaceString nss,
     const BSONObj& query,
     bool explain,
-    const MatchExpressionParser::ExtensionsCallback& extensionsCallback) {
+    const ExtensionsCallback& extensionsCallback) {
     const BSONObj emptyObj;
     return CanonicalQuery::canonicalize(std::move(nss),
                                         query,
@@ -137,7 +135,7 @@ StatusWith<std::unique_ptr<CanonicalQuery>> CanonicalQuery::canonicalize(
     const BSONObj& query,
     long long skip,
     long long limit,
-    const MatchExpressionParser::ExtensionsCallback& extensionsCallback) {
+    const ExtensionsCallback& extensionsCallback) {
     const BSONObj emptyObj;
     return CanonicalQuery::canonicalize(
         std::move(nss), query, emptyObj, emptyObj, skip, limit, extensionsCallback);
@@ -149,7 +147,7 @@ StatusWith<std::unique_ptr<CanonicalQuery>> CanonicalQuery::canonicalize(
     const BSONObj& query,
     const BSONObj& sort,
     const BSONObj& proj,
-    const MatchExpressionParser::ExtensionsCallback& extensionsCallback) {
+    const ExtensionsCallback& extensionsCallback) {
     return CanonicalQuery::canonicalize(
         std::move(nss), query, sort, proj, 0, 0, extensionsCallback);
 }
@@ -162,7 +160,7 @@ StatusWith<std::unique_ptr<CanonicalQuery>> CanonicalQuery::canonicalize(
     const BSONObj& proj,
     long long skip,
     long long limit,
-    const MatchExpressionParser::ExtensionsCallback& extensionsCallback) {
+    const ExtensionsCallback& extensionsCallback) {
     const BSONObj emptyObj;
     return CanonicalQuery::canonicalize(
         std::move(nss), query, sort, proj, skip, limit, emptyObj, extensionsCallback);
@@ -177,7 +175,7 @@ StatusWith<std::unique_ptr<CanonicalQuery>> CanonicalQuery::canonicalize(
     long long skip,
     long long limit,
     const BSONObj& hint,
-    const MatchExpressionParser::ExtensionsCallback& extensionsCallback) {
+    const ExtensionsCallback& extensionsCallback) {
     const BSONObj emptyObj;
     return CanonicalQuery::canonicalize(std::move(nss),
                                         query,
@@ -199,7 +197,7 @@ StatusWith<std::unique_ptr<CanonicalQuery>> CanonicalQuery::canonicalize(
 
 // static
 StatusWith<std::unique_ptr<CanonicalQuery>> CanonicalQuery::canonicalize(
-    const QueryMessage& qm, const MatchExpressionParser::ExtensionsCallback& extensionsCallback) {
+    const QueryMessage& qm, const ExtensionsCallback& extensionsCallback) {
     // Make LiteParsedQuery.
     auto lpqStatus = LiteParsedQuery::fromLegacyQueryMessage(qm);
     if (!lpqStatus.isOK()) {
@@ -211,7 +209,7 @@ StatusWith<std::unique_ptr<CanonicalQuery>> CanonicalQuery::canonicalize(
 
 // static
 StatusWith<std::unique_ptr<CanonicalQuery>> CanonicalQuery::canonicalize(
-    LiteParsedQuery* lpq, const MatchExpressionParser::ExtensionsCallback& extensionsCallback) {
+    LiteParsedQuery* lpq, const ExtensionsCallback& extensionsCallback) {
     std::unique_ptr<LiteParsedQuery> autoLpq(lpq);
 
     // Make MatchExpression.
@@ -237,7 +235,7 @@ StatusWith<std::unique_ptr<CanonicalQuery>> CanonicalQuery::canonicalize(
 StatusWith<std::unique_ptr<CanonicalQuery>> CanonicalQuery::canonicalize(
     const CanonicalQuery& baseQuery,
     MatchExpression* root,
-    const MatchExpressionParser::ExtensionsCallback& extensionsCallback) {
+    const ExtensionsCallback& extensionsCallback) {
     // TODO: we should be passing the filter corresponding to 'root' to the LPQ rather than the base
     // query's filter, baseQuery.getParsed().getFilter().
     BSONObj emptyObj;
@@ -281,7 +279,7 @@ StatusWith<std::unique_ptr<CanonicalQuery>> CanonicalQuery::canonicalize(
     const BSONObj& maxObj,
     bool snapshot,
     bool explain,
-    const MatchExpressionParser::ExtensionsCallback& extensionsCallback) {
+    const ExtensionsCallback& extensionsCallback) {
     // Pass empty sort and projection.
     BSONObj emptyObj;
 
@@ -312,7 +310,7 @@ StatusWith<std::unique_ptr<CanonicalQuery>> CanonicalQuery::canonicalize(
 }
 
 Status CanonicalQuery::init(LiteParsedQuery* lpq,
-                            const MatchExpressionParser::ExtensionsCallback& extensionsCallback,
+                            const ExtensionsCallback& extensionsCallback,
                             MatchExpression* root) {
     _pq.reset(lpq);
 
diff --git a/src/mongo/db/query/canonical_query.h b/src/mongo/db/query/canonical_query.h
index 6025770b2b9..451b81e543e 100644
--- a/src/mongo/db/query/canonical_query.h
+++ b/src/mongo/db/query/canonical_query.h
@@ -48,8 +48,7 @@ public:
      */
     static StatusWith<std::unique_ptr<CanonicalQuery>> canonicalize(
         const QueryMessage& qm,
-        const MatchExpressionParser::ExtensionsCallback& extensionsCallback =
-            MatchExpressionParser::ExtensionsCallback());
+        const ExtensionsCallback& extensionsCallback = ExtensionsCallback());
 
     /**
      * Takes ownership of 'lpq'.
@@ -60,9 +59,7 @@ public:
      * Used for finds using the find command path.
      */
     static StatusWith<std::unique_ptr<CanonicalQuery>> canonicalize(
-        LiteParsedQuery* lpq,
-        const MatchExpressionParser::ExtensionsCallback& extensionsCallback =
-            MatchExpressionParser::ExtensionsCallback());
+        LiteParsedQuery* lpq, const ExtensionsCallback& extensionsCallback = ExtensionsCallback());
 
     /**
      * For testing or for internal clients to use.
@@ -78,37 +75,32 @@ public:
     static StatusWith<std::unique_ptr<CanonicalQuery>> canonicalize(
         const CanonicalQuery& baseQuery,
         MatchExpression* root,
-        const MatchExpressionParser::ExtensionsCallback& extensionsCallback =
-            MatchExpressionParser::ExtensionsCallback());
+        const ExtensionsCallback& extensionsCallback = ExtensionsCallback());
 
     static StatusWith<std::unique_ptr<CanonicalQuery>> canonicalize(
         NamespaceString nss,
         const BSONObj& query,
-        const MatchExpressionParser::ExtensionsCallback& extensionsCallback =
-            MatchExpressionParser::ExtensionsCallback());
+        const ExtensionsCallback& extensionsCallback = ExtensionsCallback());
 
     static StatusWith<std::unique_ptr<CanonicalQuery>> canonicalize(
         NamespaceString nss,
         const BSONObj& query,
         bool explain,
-        const MatchExpressionParser::ExtensionsCallback& extensionsCallback =
-            MatchExpressionParser::ExtensionsCallback());
+        const ExtensionsCallback& extensionsCallback = ExtensionsCallback());
 
     static StatusWith<std::unique_ptr<CanonicalQuery>> canonicalize(
         NamespaceString nss,
         const BSONObj& query,
         long long skip,
         long long limit,
-        const MatchExpressionParser::ExtensionsCallback& extensionsCallback =
-            MatchExpressionParser::ExtensionsCallback());
+        const ExtensionsCallback& extensionsCallback = ExtensionsCallback());
 
     static StatusWith<std::unique_ptr<CanonicalQuery>> canonicalize(
         NamespaceString nss,
         const BSONObj& query,
         const BSONObj& sort,
         const BSONObj& proj,
-        const MatchExpressionParser::ExtensionsCallback& extensionsCallback =
-            MatchExpressionParser::ExtensionsCallback());
+        const ExtensionsCallback& extensionsCallback = ExtensionsCallback());
 
     static StatusWith<std::unique_ptr<CanonicalQuery>> canonicalize(
         NamespaceString nss,
@@ -117,8 +109,7 @@ public:
         const BSONObj& proj,
         long long skip,
         long long limit,
-        const MatchExpressionParser::ExtensionsCallback& extensionsCallback =
-            MatchExpressionParser::ExtensionsCallback());
+        const ExtensionsCallback& extensionsCallback = ExtensionsCallback());
 
     static StatusWith<std::unique_ptr<CanonicalQuery>> canonicalize(
         NamespaceString nss,
@@ -128,8 +119,7 @@ public:
         long long skip,
         long long limit,
         const BSONObj& hint,
-        const MatchExpressionParser::ExtensionsCallback& extensionsCallback =
-            MatchExpressionParser::ExtensionsCallback());
+        const ExtensionsCallback& extensionsCallback = ExtensionsCallback());
 
     static StatusWith<std::unique_ptr<CanonicalQuery>> canonicalize(
         NamespaceString nss,
@@ -143,8 +133,7 @@ public:
         const BSONObj& maxObj,
         bool snapshot,
         bool explain,
-        const MatchExpressionParser::ExtensionsCallback& extensionsCallback =
-            MatchExpressionParser::ExtensionsCallback());
+        const ExtensionsCallback& extensionsCallback = ExtensionsCallback());
 
     /**
      * Returns true if "query" describes an exact-match query on _id, possibly with
@@ -216,7 +205,7 @@ private:
      * Takes ownership of 'root' and 'lpq'.
      */
     Status init(LiteParsedQuery* lpq,
-                const MatchExpressionParser::ExtensionsCallback& extensionsCallback,
+                const ExtensionsCallback& extensionsCallback,
                 MatchExpression* root);
 
     std::unique_ptr<LiteParsedQuery> _pq;
diff --git a/src/mongo/db/query/get_executor.cpp b/src/mongo/db/query/get_executor.cpp
index 497f1221e57..592976395ee 100644
--- a/src/mongo/db/query/get_executor.cpp
+++ b/src/mongo/db/query/get_executor.cpp
@@ -1159,7 +1159,7 @@ StatusWith<unique_ptr<PlanExecutor>> getExecutorCount(OperationContext* txn,
     unique_ptr<CanonicalQuery> cq;
     if (!request.getQuery().isEmpty() || !request.getHint().isEmpty()) {
         // If query or hint is not empty, canonicalize the query before working with collection.
-        typedef MatchExpressionParser::ExtensionsCallback ExtensionsCallback;
+        typedef ExtensionsCallback ExtensionsCallback;
         auto statusWithCQ = CanonicalQuery::canonicalize(
             request.getNs(),
             request.getQuery(),
diff --git a/src/mongo/db/query/parsed_projection.cpp b/src/mongo/db/query/parsed_projection.cpp
index b6e086be320..b977931613c 100644
--- a/src/mongo/db/query/parsed_projection.cpp
+++ b/src/mongo/db/query/parsed_projection.cpp
@@ -48,7 +48,7 @@ using std::string;
 Status ParsedProjection::make(const BSONObj& spec,
                               const MatchExpression* const query,
                               ParsedProjection** out,
-                              const MatchExpressionParser::ExtensionsCallback& extensionsCallback) {
+                              const ExtensionsCallback& extensionsCallback) {
     // Whether we're including or excluding fields.
     enum class IncludeExclude { kUninitialized, kInclude, kExclude };
     IncludeExclude includeExclude = IncludeExclude::kUninitialized;
diff --git a/src/mongo/db/query/parsed_projection.h b/src/mongo/db/query/parsed_projection.h
index 2726e043ac3..06571199d89 100644
--- a/src/mongo/db/query/parsed_projection.h
+++ b/src/mongo/db/query/parsed_projection.h
@@ -48,8 +48,7 @@ public:
     static Status make(const BSONObj& spec,
                        const MatchExpression* const query,
                        ParsedProjection** out,
-                       const MatchExpressionParser::ExtensionsCallback& extensionsCallback =
-                           MatchExpressionParser::ExtensionsCallback());
+                       const ExtensionsCallback& extensionsCallback = ExtensionsCallback());
 
     /**
      * Returns true if the projection requires match details from the query,
diff --git a/src/mongo/dbtests/matchertests.cpp b/src/mongo/dbtests/matchertests.cpp
index 2d009406e24..f700a6f1ba4 100644
--- a/src/mongo/dbtests/matchertests.cpp
+++ b/src/mongo/dbtests/matchertests.cpp
@@ -57,7 +57,7 @@ class Basic {
 public:
     void run() {
         BSONObj query = fromjson("{\"a\":\"b\"}");
-        M m(query, MatchExpressionParser::ExtensionsCallback());
+        M m(query, ExtensionsCallback());
         ASSERT(m.matches(fromjson("{\"a\":\"b\"}")));
     }
 };
@@ -67,7 +67,7 @@ class DoubleEqual {
 public:
     void run() {
         BSONObj query = fromjson("{\"a\":5}");
-        M m(query, MatchExpressionParser::ExtensionsCallback());
+        M m(query, ExtensionsCallback());
         ASSERT(m.matches(fromjson("{\"a\":5}")));
     }
 };
@@ -78,7 +78,7 @@ public:
     void run() {
         BSONObjBuilder query;
         query.append("a", 5);
-        M m(query.done(), MatchExpressionParser::ExtensionsCallback());
+        M m(query.done(), ExtensionsCallback());
         ASSERT(m.matches(fromjson("{\"a\":5}")));
     }
 };
@@ -88,7 +88,7 @@ class MixedNumericGt {
 public:
     void run() {
         BSONObj query = fromjson("{\"a\":{\"$gt\":4}}");
-        M m(query, MatchExpressionParser::ExtensionsCallback());
+        M m(query, ExtensionsCallback());
         BSONObjBuilder b;
         b.append("a", 5);
         ASSERT(m.matches(b.done()));
@@ -103,7 +103,7 @@ public:
         ASSERT_EQUALS(4, query["a"].embeddedObject()["$in"].embeddedObject()["0"].number());
         ASSERT_EQUALS(NumberInt, query["a"].embeddedObject()["$in"].embeddedObject()["0"].type());
 
-        M m(query, MatchExpressionParser::ExtensionsCallback());
+        M m(query, ExtensionsCallback());
 
         {
             BSONObjBuilder b;
@@ -130,7 +130,7 @@ template <typename M>
 class MixedNumericEmbedded {
 public:
     void run() {
-        M m(BSON("a" << BSON("x" << 1)), MatchExpressionParser::ExtensionsCallback());
+        M m(BSON("a" << BSON("x" << 1)), ExtensionsCallback());
         ASSERT(m.matches(BSON("a" << BSON("x" << 1))));
         ASSERT(m.matches(BSON("a" << BSON("x" << 1.0))));
     }
@@ -140,7 +140,7 @@ template <typename M>
 class Size {
 public:
     void run() {
-        M m(fromjson("{a:{$size:4}}"), MatchExpressionParser::ExtensionsCallback());
+        M m(fromjson("{a:{$size:4}}"), ExtensionsCallback());
         ASSERT(m.matches(fromjson("{a:[1,2,3,4]}")));
         ASSERT(!m.matches(fromjson("{a:[1,2,3]}")));
         ASSERT(!m.matches(fromjson("{a:[1,2,3,'a','b']}")));
@@ -152,8 +152,7 @@ template <typename M>
 class WithinBox {
 public:
     void run() {
-        M m(fromjson("{loc:{$within:{$box:[{x: 4, y:4},[6,6]]}}}"),
-            MatchExpressionParser::ExtensionsCallback());
+        M m(fromjson("{loc:{$within:{$box:[{x: 4, y:4},[6,6]]}}}"), ExtensionsCallback());
         ASSERT(!m.matches(fromjson("{loc: [3,4]}")));
         ASSERT(m.matches(fromjson("{loc: [4,4]}")));
         ASSERT(m.matches(fromjson("{loc: [5,5]}")));
@@ -167,7 +166,7 @@ class WithinPolygon {
 public:
     void run() {
         M m(fromjson("{loc:{$within:{$polygon:[{x:0,y:0},[0,5],[5,5],[5,0]]}}}"),
-            MatchExpressionParser::ExtensionsCallback());
+            ExtensionsCallback());
         ASSERT(m.matches(fromjson("{loc: [3,4]}")));
         ASSERT(m.matches(fromjson("{loc: [4,4]}")));
         ASSERT(m.matches(fromjson("{loc: {x:5,y:5}}")));
@@ -180,8 +179,7 @@ template <typename M>
 class WithinCenter {
 public:
     void run() {
-        M m(fromjson("{loc:{$within:{$center:[{x:30,y:30},10]}}}"),
-            MatchExpressionParser::ExtensionsCallback());
+        M m(fromjson("{loc:{$within:{$center:[{x:30,y:30},10]}}}"), ExtensionsCallback());
         ASSERT(!m.matches(fromjson("{loc: [3,4]}")));
         ASSERT(m.matches(fromjson("{loc: {x:30,y:30}}")));
         ASSERT(m.matches(fromjson("{loc: [20,30]}")));
@@ -197,7 +195,7 @@ template <typename M>
 class ElemMatchKey {
 public:
     void run() {
-        M matcher(BSON("a.b" << 1), MatchExpressionParser::ExtensionsCallback());
+        M matcher(BSON("a.b" << 1), ExtensionsCallback());
         MatchDetails details;
         details.requestElemMatchKey();
         ASSERT(!details.hasElemMatchKey());
@@ -228,7 +226,7 @@ template <typename M>
 class TimingBase {
 public:
     long dotime(const BSONObj& patt, const BSONObj& obj) {
-        M m(patt, MatchExpressionParser::ExtensionsCallback());
+        M m(patt, ExtensionsCallback());
         Timer t;
         for (int i = 0; i < 900000; i++) {
             if (!m.matches(obj)) {