SERVER-23114 Move functions involving dotted paths to separate library.

The ability to specify a dotted path (e.g. "a.b") to traverse through
embedded objects and array elements isn't defined in the BSON
specification and so it doesn't belong in our BSON library.

The following functions have been defined within a 'dotted_path_support'
namespace and accept an additional BSONObj as their first argument to
replace the associated method on the BSONObj class.

  - extractElementAtPath() is functionally equivalent to
    BSONObj::getFieldDotted().

  - extractElementAtPathOrArrayAlongPath() is functionally equivalent to
    BSONObj::getFieldDottedOrArray().

  - extractAllElementsAlongPath() is functionally equivalent to
    BSONObj::getFieldsDotted().

  - extractElementsBasedOnTemplate() is functionally equivalent to
    BSONObj::extractFields().

  - compareObjectsAccordingToSort() is functionally equivalent to
    BSONObj::woSortOrder().

2 files changed, 9 insertions, 5 deletions

diff --git a/src/mongo/db/geo/SConscript b/src/mongo/db/geo/SConscript
index 9c8e13d1268..ca2d94c7349 100644
--- a/src/mongo/db/geo/SConscript
+++ b/src/mongo/db/geo/SConscript
@@ -16,6 +16,7 @@ env.Library("geoparser", [ "geoparser.cpp",
                            "geometry_container.cpp" ],
             LIBDEPS = [ "geometry",
                         "$BUILD_DIR/mongo/base",
+                        "$BUILD_DIR/mongo/db/bson/dotted_path_support",
                         "$BUILD_DIR/third_party/s2/s2" ])
 
 env.CppUnitTest("hash_test", [ "hash_test.cpp" ],
diff --git a/src/mongo/db/geo/geoparser.cpp b/src/mongo/db/geo/geoparser.cpp
index 7e58a768aa8..2be29d1dd7a 100644
--- a/src/mongo/db/geo/geoparser.cpp
+++ b/src/mongo/db/geo/geoparser.cpp
@@ -34,6 +34,7 @@
 #include <string>
 #include <vector>
 
+#include "mongo/db/bson/dotted_path_support.h"
 #include "mongo/db/geo/shapes.h"
 #include "mongo/db/jsobj.h"
 #include "mongo/util/log.h"
@@ -47,6 +48,8 @@ namespace mongo {
 using std::unique_ptr;
 using std::stringstream;
 
+namespace dps = ::mongo::dotted_path_support;
+
 // This field must be present, and...
 static const string GEOJSON_TYPE = "type";
 // Have one of these values:
@@ -525,7 +528,7 @@ Status GeoParser::parseMultiPoint(const BSONObj& obj, MultiPointWithCRS* out) {
         return status;
 
     out->points.clear();
-    BSONElement coordElt = obj.getFieldDotted(GEOJSON_COORDINATES);
+    BSONElement coordElt = dps::extractElementAtPath(obj, GEOJSON_COORDINATES);
     status = parseArrayOfCoordinates(coordElt, &out->points);
     if (!status.isOK())
         return status;
@@ -546,7 +549,7 @@ Status GeoParser::parseMultiLine(const BSONObj& obj, bool skipValidation, MultiL
     if (!status.isOK())
         return status;
 
-    BSONElement coordElt = obj.getFieldDotted(GEOJSON_COORDINATES);
+    BSONElement coordElt = dps::extractElementAtPath(obj, GEOJSON_COORDINATES);
     if (Array != coordElt.type())
         return BAD_VALUE("MultiLineString coordinates must be an array");
 
@@ -576,7 +579,7 @@ Status GeoParser::parseMultiPolygon(const BSONObj& obj,
     if (!status.isOK())
         return status;
 
-    BSONElement coordElt = obj.getFieldDotted(GEOJSON_COORDINATES);
+    BSONElement coordElt = dps::extractElementAtPath(obj, GEOJSON_COORDINATES);
     if (Array != coordElt.type())
         return BAD_VALUE("MultiPolygon coordinates must be an array");
 
@@ -668,7 +671,7 @@ Status GeoParser::parseCenterSphere(const BSONObj& obj, CapWithCRS* out) {
 Status GeoParser::parseGeometryCollection(const BSONObj& obj,
                                           bool skipValidation,
                                           GeometryCollection* out) {
-    BSONElement coordElt = obj.getFieldDotted(GEOJSON_GEOMETRIES);
+    BSONElement coordElt = dps::extractElementAtPath(obj, GEOJSON_GEOMETRIES);
     if (Array != coordElt.type())
         return BAD_VALUE("GeometryCollection geometries must be an array");
 
@@ -780,7 +783,7 @@ GeoParser::GeoSpecifier GeoParser::parseGeoSpecifier(const BSONElement& type) {
 }
 
 GeoParser::GeoJSONType GeoParser::parseGeoJSONType(const BSONObj& obj) {
-    BSONElement type = obj.getFieldDotted(GEOJSON_TYPE);
+    BSONElement type = dps::extractElementAtPath(obj, GEOJSON_TYPE);
     if (String != type.type()) {
         return GeoParser::GEOJSON_UNKNOWN;
     }