[Sync] Show the error on sync-internals when connection not available

This CL plumbs the network error code through to show it in the
chrome://sync-internals pages in case of NETWORK_CONNECTION_UNAVAILABLE.

This should allow for easier debugging for some user reported bugs.

Bug: 897049
Change-Id: Id0fc5455eb4d64b1a022898d8a898e7efa4a255c
Reviewed-on: https://chromium-review.googlesource.com/c/1346460
Commit-Queue: Mohamed Amir Yosef <mamir@chromium.org>
Reviewed-by: Misha Efimov <mef@chromium.org>
Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611113}

components/sync/base/DEPS

@@ -10,4 +10,5 @@ include_rules = [
   "+crypto",
   "+google/cacheinvalidation",
   "+third_party/zlib",  # For UniquePosition compression
+  "+net/base",
 ]

components/sync/base/syncer_error.cc

@@ -5,6 +5,7 @@
 #include "components/sync/base/syncer_error.h"
 
 #include "base/logging.h"
+#include "net/base/net_errors.h"
 
 namespace syncer {
 
@@ -14,7 +15,7 @@ namespace {
   case SyncerError::x: \
     return #x;         \
     break;
-const char* GetSyncerErrorString(SyncerError::Value value) {
+std::string GetSyncerErrorString(SyncerError::Value value) {
   switch (value) {
     ENUM_CASE(UNSET);
     ENUM_CASE(CANNOT_DO_WORK);
@@ -46,10 +47,12 @@ const char* GetSyncerErrorString(SyncerError::Value value) {
 
 }  // namespace
 
-SyncerError::~SyncerError() = default;
-
-const char* SyncerError::ToString() const {
+std::string SyncerError::ToString() const {
+  if (value_ != NETWORK_CONNECTION_UNAVAILABLE) {
     return GetSyncerErrorString(value_);
+  }
+  return GetSyncerErrorString(value_) + " (" +
+         net::ErrorToShortString(net_error_code_) + ")";
 }
 
 bool SyncerError::IsActualError() const {

components/sync/base/syncer_error.h

@@ -5,6 +5,8 @@
 #ifndef COMPONENTS_SYNC_BASE_SYNCER_ERROR_H_
 #define COMPONENTS_SYNC_BASE_SYNCER_ERROR_H_
 
+#include <string>
+
 namespace syncer {
 
 // This class describes all the possible results of a sync cycle. It should be
@@ -43,19 +45,30 @@ class SyncerError {
     SYNCER_OK
   };
 
-  constexpr SyncerError() : value_(UNSET) {}
-  explicit constexpr SyncerError(Value value) : value_(value) {}
-  ~SyncerError();
+  constexpr SyncerError() : value_(UNSET), net_error_code_(0) {}
+
+  explicit constexpr SyncerError(Value value)
+      : value_(value), net_error_code_(0) {}
+
+  static constexpr SyncerError NetworkConnectionUnavailable(
+      int net_error_code) {
+    return SyncerError(NETWORK_CONNECTION_UNAVAILABLE, net_error_code);
+  }
 
   Value value() const { return value_; }
-  const char* ToString() const;
+
+  std::string ToString() const;
 
   // Helper to check that |error| is set to something (not UNSET) and is not
   // SYNCER_OK or SERVER_MORE_TO_DOWNLOAD.
   bool IsActualError() const;
 
  private:
+  constexpr SyncerError(Value value, int net_error_code)
+      : value_(value), net_error_code_(net_error_code) {}
+
   Value value_;
+  int net_error_code_;
 };
 
 }  // namespace syncer

components/sync/engine_impl/events/clear_server_data_response_event.cc

@@ -26,7 +26,7 @@ std::string ClearServerDataResponseEvent::GetType() const {
 }
 
 std::string ClearServerDataResponseEvent::GetDetails() const {
-  return base::StringPrintf("Result: %s", result_.ToString());
+  return "Result: " + result_.ToString();
 }
 
 std::unique_ptr<base::DictionaryValue>

components/sync/engine_impl/events/commit_response_event.cc

@@ -26,7 +26,7 @@ std::string CommitResponseEvent::GetType() const {
 }
 
 std::string CommitResponseEvent::GetDetails() const {
-  return base::StringPrintf("Result: %s", result_.ToString());
+  return "Result: " + result_.ToString();
 }
 
 std::unique_ptr<base::DictionaryValue> CommitResponseEvent::GetProtoMessage(

components/sync/engine_impl/events/get_updates_response_event.cc

@@ -34,7 +34,7 @@ std::string GetUpdatesResponseEvent::GetDetails() const {
       return base::StringPrintf("Received %d update(s).  Some updates remain.",
                                 response_.get_updates().entries_size());
     default:
-      return base::StringPrintf("Received error: %s", error_.ToString());
+      return "Received error: " + error_.ToString();
   }
 }
 

components/sync/engine_impl/net/server_connection_manager.cc

@@ -201,6 +201,7 @@ bool ServerConnectionManager::PostBufferWithCachedAuth(
       MakeSyncServerPath(proto_sync_path(), MakeSyncQueryString(client_id_));
   bool result = PostBufferToPath(params, path, auth_token());
   SetServerStatus(params->response.server_status);
+  net_error_code_ = params->response.net_error_code;
   return result;
 }
 

components/sync/engine_impl/net/server_connection_manager.h

@@ -54,6 +54,9 @@ struct HttpResponse {
     SERVER_CONNECTION_OK,
   };
 
+  // The network error code.
+  int net_error_code;
+
   // The HTTP Status code.
   int http_status_code;
 
@@ -163,6 +166,11 @@ class ServerConnectionManager {
     return server_status_;
   }
 
+  inline int net_error_code() const {
+    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
+    return net_error_code_;
+  }
+
   const std::string client_id() const { return client_id_; }
 
   // Factory method to create an Connection object we can use for
@@ -231,6 +239,11 @@ class ServerConnectionManager {
 
   HttpResponse::ServerConnectionCode server_status_;
 
+  // Contains the network error code if there is an error when making the
+  // connection with the server in which case |server_status_| is set to
+  // HttpResponse::CONNECTION_UNAVAILABLE.
+  int net_error_code_;
+
   SEQUENCE_CHECKER(sequence_checker_);
 
   CancelationSignal* const cancelation_signal_;

components/sync/engine_impl/net/sync_server_connection_manager.cc

@@ -70,6 +70,7 @@ bool SyncBridgedConnection::Init(const char* path,
     DCHECK_NE(net_error_code, net::OK);
     DVLOG(1) << "Http POST failed, error returns: " << net_error_code;
     response->server_status = HttpResponse::CONNECTION_UNAVAILABLE;
+    response->net_error_code = net_error_code;
     return false;
   }
 

components/sync/engine_impl/syncer_proto_util.cc

@@ -83,10 +83,11 @@ void LogResponseProfilingData(const ClientToServerResponse& response) {
 }
 
 SyncerError ServerConnectionErrorAsSyncerError(
-    const HttpResponse::ServerConnectionCode server_status) {
+    const HttpResponse::ServerConnectionCode server_status,
+    int net_error_code) {
   switch (server_status) {
     case HttpResponse::CONNECTION_UNAVAILABLE:
-      return SyncerError(SyncerError::NETWORK_CONNECTION_UNAVAILABLE);
+      return SyncerError::NetworkConnectionUnavailable(net_error_code);
     case HttpResponse::IO_ERROR:
       return SyncerError(SyncerError::NETWORK_IO_ERROR);
     case HttpResponse::SYNC_SERVER_ERROR:
@@ -390,7 +391,9 @@ SyncerError SyncerProtoUtil::PostClientToServerMessage(
     DCHECK_NE(server_status, HttpResponse::NONE);
     DCHECK_NE(server_status, HttpResponse::SERVER_CONNECTION_OK);
 
-    return ServerConnectionErrorAsSyncerError(server_status);
+    return ServerConnectionErrorAsSyncerError(
+        server_status,
+        cycle->context()->connection_manager()->net_error_code());
   }
   LogClientToServerResponse(*response);