Reduce the scope of class friendships

src/impl/async_query.cpp

@@ -28,10 +28,10 @@ AsyncQuery::AsyncQuery(Results& target)
 : m_target_results(&target)
 , m_realm(target.get_realm())
 , m_sort(target.get_sort())
-, m_version(m_realm->m_shared_group->get_version_of_current_transaction())
+, m_version(Realm::Internal::get_shared_group(*m_realm).get_version_of_current_transaction())
 {
     Query q = target.get_query();
-    m_query_handover = m_realm->m_shared_group->export_for_handover(q, MutableSourcePayload::Move);
+    m_query_handover = Realm::Internal::get_shared_group(*m_realm).export_for_handover(q, MutableSourcePayload::Move);
 }
 
 size_t AsyncQuery::add_callback(std::function<void (std::exception_ptr)> callback)
@@ -176,7 +176,7 @@ void AsyncQuery::deliver(SharedGroup& sg, std::exception_ptr err)
 
     REALM_ASSERT(!m_query_handover);
 
-    auto realm_version = m_realm->m_shared_group->get_version_of_current_transaction();
+    auto realm_version = Realm::Internal::get_shared_group(*m_realm).get_version_of_current_transaction();
     if (m_version != realm_version) {
         // Realm version can be newer if a commit was made on our thread or the
         // user manually called refresh(), or older if a commit was made on a

src/impl/realm_coordinator.cpp

@@ -214,11 +214,9 @@ void RealmCoordinator::pin_version(uint_fast64_t version, uint_fast32_t index)
     SharedGroup::VersionID versionid(version, index);
     if (!m_advancer_sg) {
         try {
-            // Use a temporary Realm instance to open the shared group to reuse
+            std::unique_ptr<Group> read_only_group;
-            // the error handling there
+            Realm::open_with_config(m_config, m_advancer_history, m_advancer_sg, read_only_group);
-            Realm tmp(m_config);
+            REALM_ASSERT(!read_only_group);
-            m_advancer_history = std::move(tmp.m_history);
-            m_advancer_sg = std::move(tmp.m_shared_group);
             m_advancer_sg->begin_read(versionid);
         }
         catch (...) {
@@ -242,7 +240,7 @@ void RealmCoordinator::pin_version(uint_fast64_t version, uint_fast32_t index)
 void RealmCoordinator::register_query(std::shared_ptr<AsyncQuery> query)
 {
     auto version = query->version();
-    auto& self = *query->get_realm().m_coordinator;
+    auto& self = Realm::Internal::get_coordinator(query->get_realm());
     {
         std::lock_guard<std::mutex> lock(self.m_query_mutex);
         self.pin_version(version.version, version.index);
@@ -266,7 +264,7 @@ void RealmCoordinator::unregister_query(AsyncQuery& query)
         return false;
     };
 
-    auto& self = *query.get_realm().m_coordinator;
+    auto& self = Realm::Internal::get_coordinator(query.get_realm());
     std::lock_guard<std::mutex> lock(self.m_query_mutex);
     if (swap_remove(self.m_queries)) {
         // Make sure we aren't holding on to read versions needlessly if there
@@ -348,9 +346,9 @@ void RealmCoordinator::open_helper_shared_group()
 {
     if (!m_query_sg) {
         try {
-            Realm tmp(m_config);
+            std::unique_ptr<Group> read_only_group;
-            m_query_history = std::move(tmp.m_history);
+            Realm::open_with_config(m_config, m_query_history, m_query_sg, read_only_group);
-            m_query_sg = std::move(tmp.m_shared_group);
+            REALM_ASSERT(!read_only_group);
             m_query_sg->begin_read();
         }
         catch (...) {
@@ -412,6 +410,9 @@ void RealmCoordinator::advance_to_ready(Realm& realm)
 {
     decltype(m_queries) queries;
 
+    auto& sg = Realm::Internal::get_shared_group(realm);
+    auto& history = Realm::Internal::get_history(realm);
+
     std::lock_guard<std::mutex> lock(m_query_version_mutex);
     {
         std::lock_guard<std::mutex> lock(m_query_mutex);
@@ -426,20 +427,20 @@ void RealmCoordinator::advance_to_ready(Realm& realm)
 
         // no untargeted async queries; just advance to latest
         if (version.version == 0) {
-            transaction::advance(*realm.m_shared_group, *realm.m_history, realm.m_binding_context.get());
+            transaction::advance(sg, history, realm.m_binding_context.get());
             return;
         }
         // async results are out of date; ignore
-        else if (version < realm.m_shared_group->get_version_of_current_transaction()) {
+        else if (version < sg.get_version_of_current_transaction()) {
             return;
         }
 
-        transaction::advance(*realm.m_shared_group, *realm.m_history, realm.m_binding_context.get(), version);
+        transaction::advance(sg, history, realm.m_binding_context.get(), version);
         queries = m_queries;
     }
 
     for (auto& query : queries) {
-        query->deliver(*realm.m_shared_group, m_async_error);
+        query->deliver(sg, m_async_error);
     }
 }
 
@@ -451,8 +452,9 @@ void RealmCoordinator::process_available_async(Realm& realm)
         queries = m_queries;
     }
 
+    auto& sg = Realm::Internal::get_shared_group(realm);
     std::lock_guard<std::mutex> lock(m_query_version_mutex);
     for (auto& query : queries) {
-        query->deliver(*realm.m_shared_group, m_async_error);
+        query->deliver(sg, m_async_error);
     }
 }

src/shared_realm.cpp

@@ -63,22 +63,33 @@ Realm::Config& Realm::Config::operator=(realm::Realm::Config const& c)
 Realm::Realm(Config config)
 : m_config(std::move(config))
 {
-    try {
+    open_with_config(m_config, m_history, m_shared_group, m_read_only_group);
-        if (m_config.read_only) {
+
-            m_read_only_group = std::make_unique<Group>(m_config.path, m_config.encryption_key.data(), Group::mode_ReadOnly);
+    if (m_read_only_group) {
         m_group = m_read_only_group.get();
     }
+}
+
+void Realm::open_with_config(const Config& config,
+                             std::unique_ptr<ClientHistory>& history,
+                             std::unique_ptr<SharedGroup>& shared_group,
+                             std::unique_ptr<Group>& read_only_group)
+{
+    try {
+        if (config.read_only) {
+            read_only_group = std::make_unique<Group>(config.path, config.encryption_key.data(), Group::mode_ReadOnly);
+        }
         else {
-            m_history = realm::make_client_history(m_config.path, m_config.encryption_key.data());
+            history = realm::make_client_history(config.path, config.encryption_key.data());
-            SharedGroup::DurabilityLevel durability = m_config.in_memory ? SharedGroup::durability_MemOnly :
+            SharedGroup::DurabilityLevel durability = config.in_memory ? SharedGroup::durability_MemOnly :
                                                                            SharedGroup::durability_Full;
-            m_shared_group = std::make_unique<SharedGroup>(*m_history, durability, m_config.encryption_key.data(), !m_config.disable_format_upgrade);
+            shared_group = std::make_unique<SharedGroup>(*history, durability, config.encryption_key.data(), !config.disable_format_upgrade);
         }
     }
     catch (util::File::PermissionDenied const& ex) {
         throw RealmFileException(RealmFileException::Kind::PermissionDenied, ex.get_path(),
                                  "Unable to open a realm at path '" + ex.get_path() +
-                                 "'. Please use a path where your app has " + (m_config.read_only ? "read" : "read-write") + " permissions.");
+                                 "'. Please use a path where your app has " + (config.read_only ? "read" : "read-write") + " permissions.");
     }
     catch (util::File::Exists const& ex) {
         throw RealmFileException(RealmFileException::Kind::Exists, ex.get_path(),
@@ -93,12 +104,12 @@ Realm::Realm(Config config)
                                  "Unable to open a realm at path '" + ex.get_path() + "'");
     }
     catch (IncompatibleLockFile const& ex) {
-        throw RealmFileException(RealmFileException::Kind::IncompatibleLockFile, m_config.path,
+        throw RealmFileException(RealmFileException::Kind::IncompatibleLockFile, config.path,
                                  "Realm file is currently open in another process "
                                  "which cannot share access with this process. All processes sharing a single file must be the same architecture.");
     }
     catch (FileFormatUpgradeRequired const& ex) {
-        throw RealmFileException(RealmFileException::Kind::FormatUpgradeRequired, m_config.path,
+        throw RealmFileException(RealmFileException::Kind::FormatUpgradeRequired, config.path,
                                  "The Realm file format must be allowed to be upgraded "
                                  "in order to proceed.");
     }

src/shared_realm.hpp

@@ -116,6 +116,21 @@ namespace realm {
         void init(std::shared_ptr<_impl::RealmCoordinator> coordinator);
         Realm(Config config);
 
+        // Give AsyncQuery direct access to the shared group as it needs it to
+        // call the handover functions
+        class Internal {
+            friend class _impl::AsyncQuery;
+            friend class _impl::RealmCoordinator;
+            static SharedGroup& get_shared_group(Realm& realm) { return *realm.m_shared_group; }
+            static ClientHistory& get_history(Realm& realm) { return *realm.m_history; }
+            static _impl::RealmCoordinator& get_coordinator(Realm& realm) { return *realm.m_coordinator; }
+        };
+
+        static void open_with_config(const Config& config,
+                                     std::unique_ptr<ClientHistory>& history,
+                                     std::unique_ptr<SharedGroup>& shared_group,
+                                     std::unique_ptr<Group>& read_only_group);
+
       private:
         Config m_config;
         std::thread::id m_thread_id = std::this_thread::get_id();
@@ -135,9 +150,6 @@ namespace realm {
 
         // FIXME private
         Group *read_group();
-
-        friend class _impl::AsyncQuery;
-        friend class _impl::RealmCoordinator;
     };
 
     class RealmFileException : public std::runtime_error {