Change ListCollections, ListIndexes, and ListDatabases to use CompositeSelector.

GODRIVER-735

Change-Id: Ic9627f5faa8249a860620642989dc2d292d97cd8

Author: Divjot Arora

mongo/client.go

@@ -358,10 +358,14 @@ func (c *Client) ListDatabases(ctx context.Context, filter interface{}, opts ...
 		Clock:   c.clock,
 	}
 
+	readSelector := description.CompositeSelector([]description.ServerSelector{
+		description.ReadPrefSelector(readpref.Primary()),
+		description.LatencySelector(c.localThreshold),
+	})
 	res, err := driver.ListDatabases(
 		ctx, cmd,
 		c.topology,
-		description.ReadPrefSelector(readpref.Primary()),
+		readSelector,
 		c.id,
 		c.topology.SessionPool,
 		opts...,

mongo/database.go

@@ -233,10 +233,14 @@ func (db *Database) ListCollections(ctx context.Context, filter interface{}, opt
 		Clock:    db.client.clock,
 	}
 
+	readSelector := description.CompositeSelector([]description.ServerSelector{
+		description.ReadPrefSelector(readpref.Primary()),
+		description.LatencySelector(db.client.localThreshold),
+	})
 	cursor, err := driver.ListCollections(
 		ctx, cmd,
 		db.client.topology,
-		db.readSelector,
+		readSelector,
 		db.client.id,
 		db.client.topology.SessionPool,
 		opts...,

mongo/index_view.go

@@ -16,9 +16,11 @@ import (
 	"github.com/mongodb/mongo-go-driver/bson/bsoncodec"
 	"github.com/mongodb/mongo-go-driver/bson/bsontype"
 	"github.com/mongodb/mongo-go-driver/mongo/options"
+	"github.com/mongodb/mongo-go-driver/mongo/readpref"
 	"github.com/mongodb/mongo-go-driver/x/bsonx"
 	"github.com/mongodb/mongo-go-driver/x/mongo/driver"
 	"github.com/mongodb/mongo-go-driver/x/network/command"
+	"github.com/mongodb/mongo-go-driver/x/network/description"
 )
 
 // ErrInvalidIndexValue indicates that the index Keys document has a value that isn't either a number or a string.
@@ -56,10 +58,14 @@ func (iv IndexView) List(ctx context.Context, opts ...*options.ListIndexesOption
 		Clock:   iv.coll.client.clock,
 	}
 
+	readSelector := description.CompositeSelector([]description.ServerSelector{
+		description.ReadPrefSelector(readpref.Primary()),
+		description.LatencySelector(iv.coll.client.localThreshold),
+	})
 	return driver.ListIndexes(
 		ctx, listCmd,
 		iv.coll.client.topology,
-		iv.coll.writeSelector,
+		readSelector,
 		iv.coll.client.id,
 		iv.coll.client.topology.SessionPool,
 		opts...,