Reland "Refactor IceControllerEvent" 1/n

This is a partial reland of commit 794e68cf3dbc3b16ee8b12b5615d8a1622154dbd
which
- adds a new enum - IceSwitchReason
- adds a member for the new enum in IceControllerEvent
- adds methods to IceControllerInterface accepting the new enum
- adds conversion between the old and new enums for compatibility

Original change's description:
> Refactor IceControllerEvent
>
> This change is the first step in decoupling IceControllerEvent from
> the ICE switch reason. Further cleanup is earmarked, and will be
> landed after some internal cleanup.
>
> This change
> - adds a new enum - IceSwitchReason
> - adds a member for the new enum in IceControllerEvent
> - uses the new enum within P2PTransportChannel
> - adds methods to IceControllerInterface accepting the new enum
> - deprecates usages of the old enum in IceControllerInterface
> - adds conversion between the old and new enums for compatibility
>
> Bug: webrtc:14125, webrtc:14131
> Change-Id: I5b7201c3f631eb40db334dfeec842841a7e58174
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/264140
> Reviewed-by: Jonas Oreland <jonaso@webrtc.org>
> Commit-Queue: Sameer Vijaykar <samvi@google.com>
> Cr-Commit-Position: refs/heads/main@{#37051}

Bug: webrtc:14125, webrtc:14131
Change-Id: I2ccdd53c80e38dc139669aa3f438864befed3dc0
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/264506
Commit-Queue: Sameer Vijaykar <samvi@google.com>
Reviewed-by: Jonas Oreland <jonaso@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#37094}

p2p/BUILD.gn

@@ -43,6 +43,8 @@ rtc_library("rtc_p2p") {
     "base/ice_controller_interface.h",
     "base/ice_credentials_iterator.cc",
     "base/ice_credentials_iterator.h",
+    "base/ice_switch_reason.cc",
+    "base/ice_switch_reason.h",
     "base/ice_transport_internal.cc",
     "base/ice_transport_internal.h",
     "base/p2p_constants.cc",

p2p/base/ice_controller_interface.cc

@@ -12,46 +12,71 @@
 
 #include <string>
 
+#include "p2p/base/ice_switch_reason.h"
+
 namespace cricket {
 
 std::string IceControllerEvent::ToString() const {
-  std::string reason;
+  std::string str = IceSwitchReasonToString(reason);
-  switch (type) {
-    case REMOTE_CANDIDATE_GENERATION_CHANGE:
-      reason = "remote candidate generation maybe changed";
-      break;
-    case NETWORK_PREFERENCE_CHANGE:
-      reason = "network preference changed";
-      break;
-    case NEW_CONNECTION_FROM_LOCAL_CANDIDATE:
-      reason = "new candidate pairs created from a new local candidate";
-      break;
-    case NEW_CONNECTION_FROM_REMOTE_CANDIDATE:
-      reason = "new candidate pairs created from a new remote candidate";
-      break;
-    case NEW_CONNECTION_FROM_UNKNOWN_REMOTE_ADDRESS:
-      reason = "a new candidate pair created from an unknown remote address";
-      break;
-    case NOMINATION_ON_CONTROLLED_SIDE:
-      reason = "nomination on the controlled side";
-      break;
-    case DATA_RECEIVED:
-      reason = "data received";
-      break;
-    case CONNECT_STATE_CHANGE:
-      reason = "candidate pair state changed";
-      break;
-    case SELECTED_CONNECTION_DESTROYED:
-      reason = "selected candidate pair destroyed";
-      break;
-    case ICE_CONTROLLER_RECHECK:
-      reason = "ice-controller-request-recheck";
-      break;
-  }
   if (recheck_delay_ms) {
-    reason += " (after delay: " + std::to_string(recheck_delay_ms) + ")";
+    str += " (after delay: " + std::to_string(recheck_delay_ms) + ")";
+  }
+  return str;
+}
+
+// TODO(bugs.webrtc.org/14125) remove when Type is replaced with
+// IceSwitchReason.
+IceControllerEvent::Type IceControllerEvent::FromIceSwitchReason(
+    IceSwitchReason reason) {
+  switch (reason) {
+    case IceSwitchReason::REMOTE_CANDIDATE_GENERATION_CHANGE:
+      return IceControllerEvent::REMOTE_CANDIDATE_GENERATION_CHANGE;
+    case IceSwitchReason::NETWORK_PREFERENCE_CHANGE:
+      return IceControllerEvent::NETWORK_PREFERENCE_CHANGE;
+    case IceSwitchReason::NEW_CONNECTION_FROM_LOCAL_CANDIDATE:
+      return IceControllerEvent::NEW_CONNECTION_FROM_LOCAL_CANDIDATE;
+    case IceSwitchReason::NEW_CONNECTION_FROM_REMOTE_CANDIDATE:
+      return IceControllerEvent::NEW_CONNECTION_FROM_REMOTE_CANDIDATE;
+    case IceSwitchReason::NEW_CONNECTION_FROM_UNKNOWN_REMOTE_ADDRESS:
+      return IceControllerEvent::NEW_CONNECTION_FROM_UNKNOWN_REMOTE_ADDRESS;
+    case IceSwitchReason::NOMINATION_ON_CONTROLLED_SIDE:
+      return IceControllerEvent::NOMINATION_ON_CONTROLLED_SIDE;
+    case IceSwitchReason::DATA_RECEIVED:
+      return IceControllerEvent::DATA_RECEIVED;
+    case IceSwitchReason::CONNECT_STATE_CHANGE:
+      return IceControllerEvent::CONNECT_STATE_CHANGE;
+    case IceSwitchReason::SELECTED_CONNECTION_DESTROYED:
+      return IceControllerEvent::SELECTED_CONNECTION_DESTROYED;
+    case IceSwitchReason::ICE_CONTROLLER_RECHECK:
+      return IceControllerEvent::ICE_CONTROLLER_RECHECK;
+  }
+}
+
+// TODO(bugs.webrtc.org/14125) remove when Type is replaced with
+// IceSwitchReason.
+IceSwitchReason IceControllerEvent::FromType(IceControllerEvent::Type type) {
+  switch (type) {
+    case IceControllerEvent::REMOTE_CANDIDATE_GENERATION_CHANGE:
+      return IceSwitchReason::REMOTE_CANDIDATE_GENERATION_CHANGE;
+    case IceControllerEvent::NETWORK_PREFERENCE_CHANGE:
+      return IceSwitchReason::NETWORK_PREFERENCE_CHANGE;
+    case IceControllerEvent::NEW_CONNECTION_FROM_LOCAL_CANDIDATE:
+      return IceSwitchReason::NEW_CONNECTION_FROM_LOCAL_CANDIDATE;
+    case IceControllerEvent::NEW_CONNECTION_FROM_REMOTE_CANDIDATE:
+      return IceSwitchReason::NEW_CONNECTION_FROM_REMOTE_CANDIDATE;
+    case IceControllerEvent::NEW_CONNECTION_FROM_UNKNOWN_REMOTE_ADDRESS:
+      return IceSwitchReason::NEW_CONNECTION_FROM_UNKNOWN_REMOTE_ADDRESS;
+    case IceControllerEvent::NOMINATION_ON_CONTROLLED_SIDE:
+      return IceSwitchReason::NOMINATION_ON_CONTROLLED_SIDE;
+    case IceControllerEvent::DATA_RECEIVED:
+      return IceSwitchReason::DATA_RECEIVED;
+    case IceControllerEvent::CONNECT_STATE_CHANGE:
+      return IceSwitchReason::CONNECT_STATE_CHANGE;
+    case IceControllerEvent::SELECTED_CONNECTION_DESTROYED:
+      return IceSwitchReason::SELECTED_CONNECTION_DESTROYED;
+    case IceControllerEvent::ICE_CONTROLLER_RECHECK:
+      return IceSwitchReason::ICE_CONTROLLER_RECHECK;
   }
-  return reason;
 }
 
 }  // namespace cricket

p2p/base/ice_controller_interface.h

@@ -15,7 +15,9 @@
 #include <utility>
 #include <vector>
 
+#include "absl/types/optional.h"
 #include "p2p/base/connection.h"
+#include "p2p/base/ice_switch_reason.h"
 #include "p2p/base/ice_transport_internal.h"
 
 namespace cricket {
@@ -23,6 +25,7 @@ namespace cricket {
 struct IceFieldTrials;  // Forward declaration to avoid circular dependency.
 
 struct IceControllerEvent {
+  // TODO(bugs.webrtc.org/14125) replace with IceSwitchReason.
   enum Type {
     REMOTE_CANDIDATE_GENERATION_CHANGE,
     NETWORK_PREFERENCE_CHANGE,
@@ -39,11 +42,23 @@ struct IceControllerEvent {
     ICE_CONTROLLER_RECHECK,
   };
 
+  // TODO(bugs.webrtc.org/14125) remove.
   IceControllerEvent(const Type& _type)  // NOLINT: runtime/explicit
-      : type(_type) {}
+      : type(_type), reason(FromType(_type)) {}
+
+  IceControllerEvent(IceSwitchReason _reason, int _recheck_delay_ms)
+      : type(FromIceSwitchReason(_reason)),
+        reason(_reason),
+        recheck_delay_ms(_recheck_delay_ms) {}
+
+  static Type FromIceSwitchReason(IceSwitchReason reason);
+  static IceSwitchReason FromType(Type type);
+
   std::string ToString() const;
 
+  // TODO(bugs.webrtc.org/14125) replace usage with IceSwitchReason.
   Type type;
+  IceSwitchReason reason;
   int recheck_delay_ms = 0;
 };
 
@@ -134,13 +149,22 @@ class IceControllerInterface {
   virtual void MarkConnectionPinged(const Connection* con) = 0;
 
   // Check if we should switch to `connection`.
-  // This method is called for IceControllerEvent's that can switch directly
+  // This method is called for IceSwitchReasons that can switch directly
   // i.e without resorting.
   virtual SwitchResult ShouldSwitchConnection(IceControllerEvent reason,
                                               const Connection* connection) = 0;
+  virtual SwitchResult ShouldSwitchConnection(IceSwitchReason reason,
+                                              const Connection* connection) {
+    return ShouldSwitchConnection(
+        IceControllerEvent::FromIceSwitchReason(reason), connection);
+  }
 
   // Sort connections and check if we should switch.
   virtual SwitchResult SortAndSwitchConnection(IceControllerEvent reason) = 0;
+  virtual SwitchResult SortAndSwitchConnection(IceSwitchReason reason) {
+    return SortAndSwitchConnection(
+        IceControllerEvent::FromIceSwitchReason(reason));
+  }
 
   // Prune connections.
   virtual std::vector<const Connection*> PruneConnections() = 0;

p2p/base/ice_switch_reason.cc

@@ -0,0 +1,44 @@
+/*
+ *  Copyright 2022 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 "p2p/base/ice_switch_reason.h"
+
+#include <string>
+
+namespace cricket {
+
+std::string IceSwitchReasonToString(IceSwitchReason reason) {
+  switch (reason) {
+    case IceSwitchReason::REMOTE_CANDIDATE_GENERATION_CHANGE:
+      return "remote candidate generation maybe changed";
+    case IceSwitchReason::NETWORK_PREFERENCE_CHANGE:
+      return "network preference changed";
+    case IceSwitchReason::NEW_CONNECTION_FROM_LOCAL_CANDIDATE:
+      return "new candidate pairs created from a new local candidate";
+    case IceSwitchReason::NEW_CONNECTION_FROM_REMOTE_CANDIDATE:
+      return "new candidate pairs created from a new remote candidate";
+    case IceSwitchReason::NEW_CONNECTION_FROM_UNKNOWN_REMOTE_ADDRESS:
+      return "a new candidate pair created from an unknown remote address";
+    case IceSwitchReason::NOMINATION_ON_CONTROLLED_SIDE:
+      return "nomination on the controlled side";
+    case IceSwitchReason::DATA_RECEIVED:
+      return "data received";
+    case IceSwitchReason::CONNECT_STATE_CHANGE:
+      return "candidate pair state changed";
+    case IceSwitchReason::SELECTED_CONNECTION_DESTROYED:
+      return "selected candidate pair destroyed";
+    case IceSwitchReason::ICE_CONTROLLER_RECHECK:
+      return "ice-controller-request-recheck";
+    default:
+      return "unknown";
+  }
+}
+
+}  // namespace cricket

p2p/base/ice_switch_reason.h

@@ -0,0 +1,38 @@
+/*
+ *  Copyright 2022 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 P2P_BASE_ICE_SWITCH_REASON_H_
+#define P2P_BASE_ICE_SWITCH_REASON_H_
+
+#include <string>
+
+namespace cricket {
+
+enum class IceSwitchReason {
+  REMOTE_CANDIDATE_GENERATION_CHANGE,
+  NETWORK_PREFERENCE_CHANGE,
+  NEW_CONNECTION_FROM_LOCAL_CANDIDATE,
+  NEW_CONNECTION_FROM_REMOTE_CANDIDATE,
+  NEW_CONNECTION_FROM_UNKNOWN_REMOTE_ADDRESS,
+  NOMINATION_ON_CONTROLLED_SIDE,
+  DATA_RECEIVED,
+  CONNECT_STATE_CHANGE,
+  SELECTED_CONNECTION_DESTROYED,
+  // The ICE_CONTROLLER_RECHECK enum value lets an IceController request
+  // P2PTransportChannel to recheck a switch periodically without an event
+  // taking place.
+  ICE_CONTROLLER_RECHECK,
+};
+
+std::string IceSwitchReasonToString(IceSwitchReason reason);
+
+}  // namespace cricket
+
+#endif  // P2P_BASE_ICE_SWITCH_REASON_H_