Add AbslStringify for SessionDescriptionInterface

Should be useful for debugging.

Bug: None
Change-Id: I0c048beb422ca9fb5e6d69bc76379acb272d94bc
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/364820
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#43183}

api/BUILD.gn

@@ -1540,6 +1540,7 @@ if (rtc_include_tests) {
       "candidate_unittest.cc",
       "field_trials_unittest.cc",
       "function_view_unittest.cc",
+      "jsep_unittest.cc",
       "rtc_error_unittest.cc",
       "rtc_event_log_output_file_unittest.cc",
       "rtp_packet_info_unittest.cc",
@@ -1573,6 +1574,7 @@ if (rtc_include_tests) {
       "../rtc_base:buffer",
       "../rtc_base:checks",
       "../rtc_base:gunit_helpers",
+      "../rtc_base:logging",
       "../rtc_base:macromagic",
       "../rtc_base:platform_thread",
       "../rtc_base:rtc_event",

api/DEPS

@@ -261,4 +261,8 @@ specific_include_rules = {
     "+video",
     "+third_party",
   ],
+
+  "jsep_unittest\.cc": [
+    "+absl/strings/str_cat.h",
+  ]
 }

api/jsep.h

@@ -187,6 +187,19 @@ class RTC_EXPORT SessionDescriptionInterface {
 
   // Serializes the description to SDP.
   virtual bool ToString(std::string* out) const = 0;
+  template <typename Sink>
+  friend void AbslStringify(Sink& sink, const SessionDescriptionInterface& p) {
+    sink.Append("\n--- BEGIN SDP ");
+    sink.Append(SdpTypeToString(p.GetType()));
+    sink.Append(" ---\n");
+    std::string temp;
+    if (p.ToString(&temp)) {
+      sink.Append(temp);
+    } else {
+      sink.Append("Error in ToString\n");
+    }
+    sink.Append("--- END SDP ---\n");
+  }
 };
 
 // Creates a SessionDescriptionInterface based on the SDP string and the type.

api/jsep_unittest.cc

@@ -0,0 +1,67 @@
+/*
+ *  Copyright 2024 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 "api/jsep.h"
+
+#include <memory>
+#include <string>
+
+#include "absl/strings/str_cat.h"
+#include "rtc_base/logging.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+
+namespace webrtc {
+
+using ::testing::HasSubstr;
+
+TEST(JsepTest, AbslStringifySdp) {
+  std::string sdp =
+      "v=0\r\n"
+      "o=- 0 3 IN IP4 127.0.0.1\r\n"
+      "s=-\r\n"
+      "t=0 0\r\n"
+      "a=group:BUNDLE 0 1\r\n"
+      "a=fingerprint:sha-1 "
+      "4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB\r\n"
+      "a=setup:actpass\r\n"
+      "a=ice-ufrag:ETEn\r\n"
+      "a=ice-pwd:OtSK0WpNtpUjkY4+86js7Z/l\r\n"
+      "m=audio 9 UDP/TLS/RTP/SAVPF 111\r\n"
+      "c=IN IP4 0.0.0.0\r\n"
+      "a=rtcp-mux\r\n"
+      "a=sendonly\r\n"
+      "a=mid:0\r\n"
+      "a=rtpmap:111 opus/48000/2\r\n"
+      "m=video 9 UDP/TLS/RTP/SAVPF 111\r\n"
+      "c=IN IP4 0.0.0.0\r\n"
+      "a=rtcp-mux\r\n"
+      "a=sendonly\r\n"
+      "a=mid:1\r\n"
+      "a=rtpmap:111 H264/90000\r\n"
+      "a=fmtp:111 "
+      "level-asymmetry-allowed=1;packetization-mode=0;profile-level-id="
+      "42e01f\r\n";
+
+  std::unique_ptr<SessionDescriptionInterface> some_sdp =
+      CreateSessionDescription(SdpType::kOffer, sdp);
+  // Verify that sending the SDP to the log compiles.
+  RTC_LOG(LS_VERBOSE) << "The SDP is " << *some_sdp;
+  // Since create/stringify mangles order of fields, we only test
+  // some substrings.
+  EXPECT_THAT(absl::StrCat(*some_sdp), HasSubstr("a=rtpmap:111 opus/48000"));
+  EXPECT_THAT(
+      absl::StrCat(*some_sdp),
+      HasSubstr(
+          "a=fingerprint:sha-1 "
+          "4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB\r\n"));
+}
+
+}  // namespace webrtc