dcsctp: Add DcSctpSocketFactory

The factory allows us to isolate the implementation from users who only
need to depend directly on the public folder now.

Bug: webrtc:12614
Change-Id: Ied09cf772ed427eaf17a7b5705f587da57405640
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/220939
Commit-Queue: Florent Castelli <orphis@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34330}

media/BUILD.gn

@@ -402,9 +402,9 @@ if (rtc_build_dcsctp) {
       ":rtc_data_sctp_transport_internal",
       "../api:array_view",
       "../media:rtc_media_base",
+      "../net/dcsctp/public:factory",
       "../net/dcsctp/public:socket",
       "../net/dcsctp/public:types",
-      "../net/dcsctp/socket:dcsctp_socket",
       "../net/dcsctp/timer:task_queue_timeout",
       "../p2p:rtc_p2p",
       "../rtc_base:checks",

media/sctp/dcsctp_transport.cc

@@ -19,9 +19,9 @@
 #include "absl/types/optional.h"
 #include "api/array_view.h"
 #include "media/base/media_channel.h"
+#include "net/dcsctp/public/dcsctp_socket_factory.h"
 #include "net/dcsctp/public/packet_observer.h"
 #include "net/dcsctp/public/types.h"
-#include "net/dcsctp/socket/dcsctp_socket.h"
 #include "p2p/base/packet_transport_internal.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/logging.h"
@@ -177,8 +177,9 @@ bool DcSctpTransport::Start(int local_sctp_port,
       packet_observer = std::make_unique<TextPcapPacketObserver>(debug_name_);
     }
 
-    socket_ = std::make_unique<dcsctp::DcSctpSocket>(
-        debug_name_, *this, std::move(packet_observer), options);
+    dcsctp::DcSctpSocketFactory factory;
+    socket_ =
+        factory.Create(debug_name_, *this, std::move(packet_observer), options);
   } else {
     if (local_sctp_port != socket_->options().local_port ||
         remote_sctp_port != socket_->options().remote_port) {

net/dcsctp/public/BUILD.gn

@@ -43,6 +43,19 @@ rtc_source_set("socket") {
   ]
 }
 
+rtc_source_set("factory") {
+  deps = [
+    ":socket",
+    ":types",
+    "../socket:dcsctp_socket",
+  ]
+  sources = [
+    "dcsctp_socket_factory.cc",
+    "dcsctp_socket_factory.h",
+  ]
+  absl_deps = [ "//third_party/abseil-cpp/absl/strings" ]
+}
+
 if (rtc_include_tests) {
   rtc_library("dcsctp_public_unittests") {
     testonly = true

net/dcsctp/public/dcsctp_socket_factory.cc

@@ -0,0 +1,31 @@
+/*
+ *  Copyright 2021 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "net/dcsctp/public/dcsctp_socket_factory.h"
+
+#include <memory>
+#include <utility>
+
+#include "absl/strings/string_view.h"
+#include "net/dcsctp/public/dcsctp_options.h"
+#include "net/dcsctp/public/dcsctp_socket.h"
+#include "net/dcsctp/public/packet_observer.h"
+#include "net/dcsctp/socket/dcsctp_socket.h"
+
+namespace dcsctp {
+std::unique_ptr<DcSctpSocketInterface> DcSctpSocketFactory::Create(
+    absl::string_view log_prefix,
+    DcSctpSocketCallbacks& callbacks,
+    std::unique_ptr<PacketObserver> packet_observer,
+    const DcSctpOptions& options) {
+  return std::make_unique<DcSctpSocket>(log_prefix, callbacks,
+                                        std::move(packet_observer), options);
+}
+}  // namespace dcsctp

net/dcsctp/public/dcsctp_socket_factory.h

@@ -0,0 +1,31 @@
+/*
+ *  Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#ifndef NET_DCSCTP_PUBLIC_DCSCTP_SOCKET_FACTORY_H_
+#define NET_DCSCTP_PUBLIC_DCSCTP_SOCKET_FACTORY_H_
+
+#include <memory>
+
+#include "absl/strings/string_view.h"
+#include "net/dcsctp/public/dcsctp_options.h"
+#include "net/dcsctp/public/dcsctp_socket.h"
+#include "net/dcsctp/public/packet_observer.h"
+
+namespace dcsctp {
+class DcSctpSocketFactory {
+ public:
+  std::unique_ptr<DcSctpSocketInterface> Create(
+      absl::string_view log_prefix,
+      DcSctpSocketCallbacks& callbacks,
+      std::unique_ptr<PacketObserver> packet_observer,
+      const DcSctpOptions& options);
+};
+}  // namespace dcsctp
+
+#endif  // NET_DCSCTP_PUBLIC_DCSCTP_SOCKET_FACTORY_H_