glue code for CAPI custom user via callbacks (#7615)

* glue code for CAPI custom user via callbacks

* review feedback

* remove request_refresh_user from the SyncUser interface, it is unused

* further feedback addressed

CHANGELOG.md

@@ -20,7 +20,7 @@
 ### Internals
 * Follow on to ([PR #7300](https://github.com/realm/realm-core/pull/7300)) to allow SDKs to construct a fake user for testing SyncManager::get_user -> App::create_fake_user_for_testing ([PR #7632](https://github.com/realm/realm-core/pull/7632))
 * Fix build-apple-device.sh, broken in [#7603](https://github.com/realm/realm-core/pull/7603) ([PR #7640](https://github.com/realm/realm-core/pull/7640)).
-
+* Added a CAPI interface for SDKs to bring their own managed users with core's app services turned off. ([PR #7615](https://github.com/realm/realm-core/pull/7615)).
 ----------------------------------------------
 
 # 14.6.0 Release notes

bindgen/spec.yml

@@ -1236,7 +1236,6 @@ classes:
       path_for_realm: '(config: SyncConfig&, custom_file_name: std::optional<std::string>&) -> std::string'
       access_token_refresh_required: '() -> bool'
 # #      request_log_out: '(cb: AsyncCallback<(err: std::optional<AppError>)>&&)'
-      request_refresh_user: '(cb: AsyncCallback<(err: std::optional<AppError>)>&&)'
       request_refresh_location: '(cb: AsyncCallback<(err: std::optional<AppError>)>&&)'
       request_access_token: '(cb: AsyncCallback<(err: std::optional<AppError>)>&&)'
       track_realm: '(path: std::string_view)'

src/realm.h

@@ -3451,6 +3451,34 @@ RLM_API char* realm_user_get_custom_data(const realm_user_t*) RLM_API_NOEXCEPT;
  */
 RLM_API char* realm_user_get_profile_data(const realm_user_t*);
 
+/**
+ * Return the identiy for the user passed as argument
+ * @param user ptr to the user for which the identiy has to be retrieved
+ * @return a ptr to the identity string. This must be manually released with realm_free().
+ */
+RLM_API char* realm_user_get_identity(const realm_user_t* user) RLM_API_NOEXCEPT;
+
+/**
+ * Retrieve the state for the user passed as argument
+ * @param user ptr to the user for which the state has to be retrieved
+ * @return realm_user_state_e value
+ */
+RLM_API realm_user_state_e realm_user_get_state(const realm_user_t* user) RLM_API_NOEXCEPT;
+
+RLM_API bool realm_user_is_logged_in(const realm_user_t*) RLM_API_NOEXCEPT;
+
+/**
+ * Return the access token associated with the user.
+ * @return a string that rapresents the access token
+ */
+RLM_API char* realm_user_get_access_token(const realm_user_t*);
+
+/**
+ * Return the refresh token associated with the user.
+ * @return a string that represents the refresh token
+ */
+RLM_API char* realm_user_get_refresh_token(const realm_user_t*);
+
 typedef struct realm_app_user_subscription_token realm_app_user_subscription_token_t;
 typedef void (*realm_sync_on_user_state_changed_t)(realm_userdata_t userdata, realm_user_state_e s);
 /**
@@ -3482,35 +3510,6 @@ RLM_API realm_app_t* realm_user_get_app(const realm_user_t*) RLM_API_NOEXCEPT;
 
 #endif // REALM_APP_SERVICES
 
-/**
- * Return the identiy for the user passed as argument
- * @param user ptr to the user for which the identiy has to be retrieved
- * @return a ptr to the identity string. This must be manually released with realm_free().
- */
-RLM_API char* realm_user_get_identity(const realm_user_t* user) RLM_API_NOEXCEPT;
-
-/**
- * Retrieve the state for the user passed as argument
- * @param user ptr to the user for which the state has to be retrieved
- * @return realm_user_state_e value
- */
-RLM_API realm_user_state_e realm_user_get_state(const realm_user_t* user) RLM_API_NOEXCEPT;
-
-RLM_API bool realm_user_is_logged_in(const realm_user_t*) RLM_API_NOEXCEPT;
-
-/**
- * Return the access token associated with the user.
- * @return a string that rapresents the access token
- */
-RLM_API char* realm_user_get_access_token(const realm_user_t*);
-
-/**
- * Return the refresh token associated with the user.
- * @return a string that represents the refresh token
- */
-RLM_API char* realm_user_get_refresh_token(const realm_user_t*);
-
-
 /* Sync */
 typedef enum realm_sync_client_reconnect_mode {
     RLM_SYNC_CLIENT_RECONNECT_MODE_NORMAL,
@@ -3562,8 +3561,15 @@ typedef enum realm_sync_error_action {
     RLM_SYNC_ERROR_ACTION_REVERT_TO_PBS,
 } realm_sync_error_action_e;
 
+typedef enum realm_sync_file_action {
+    RLM_SYNC_FILE_ACTION_DELETE_REALM,
+    RLM_SYNC_FILE_ACTION_BACK_UP_THEN_DELETE_REALM,
+} realm_sync_file_action_e;
+
+
 typedef struct realm_sync_session realm_sync_session_t;
 typedef struct realm_async_open_task realm_async_open_task_t;
+typedef struct realm_sync_manager realm_sync_manager_t;
 
 typedef struct realm_sync_error_user_info {
     const char* key;
@@ -3576,6 +3582,73 @@ typedef struct realm_sync_error_compensating_write_info {
     realm_value_t primary_key;
 } realm_sync_error_compensating_write_info_t;
 
+// The following interface allows C-API users to
+// bring their own users. This API shouldn't be mixed
+// with core's own implementation of User so it is
+// only defined with app services are compiled out
+#if !REALM_APP_SERVICES
+/**
+ * Generic completion callback for asynchronous Realm User operations.
+ * @param userdata This must be the faithfully forwarded data parameter that was provided along with this callback.
+ * @param error Pointer to an error object if the operation failed, otherwise null if it completed successfully.
+ */
+typedef void (*realm_user_void_completion_func_t)(realm_userdata_t userdata, const realm_app_error_t* error);
+
+
+typedef const char* (*realm_user_get_access_token_cb_t)(realm_userdata_t userdata);
+typedef const char* (*realm_user_get_refresh_token_cb_t)(realm_userdata_t userdata);
+typedef realm_user_state_e (*realm_user_state_cb_t)(realm_userdata_t userdata);
+typedef bool (*realm_user_access_token_refresh_required_cb_t)(realm_userdata_t userdata);
+typedef realm_sync_manager_t* (*realm_user_get_sync_manager_cb_t)(realm_userdata_t userdata);
+typedef void (*realm_user_request_log_out_cb_t)(realm_userdata_t userdata);
+typedef void (*realm_user_request_refresh_location_cb_t)(realm_userdata_t userdata,
+                                                         realm_user_void_completion_func_t cb,
+                                                         realm_userdata_t cb_data);
+typedef void (*realm_user_request_access_token_cb_t)(realm_userdata_t userdata, realm_user_void_completion_func_t cb,
+                                                     realm_userdata_t cb_data);
+typedef void (*realm_user_track_realm_cb_t)(realm_userdata_t userdata, const char* path);
+typedef const char* (*realm_user_create_file_action_cb_t)(realm_userdata_t userdata, realm_sync_file_action_e action,
+                                                          const char* original_path,
+                                                          const char* requested_recovery_dir);
+typedef struct realm_sync_user_create_config {
+    realm_userdata_t userdata;
+    realm_free_userdata_func_t free_func;
+    const char* app_id;
+    const char* user_id;
+    realm_user_get_access_token_cb_t access_token_cb;
+    realm_user_get_refresh_token_cb_t refresh_token_cb;
+    realm_user_state_cb_t state_cb;
+    realm_user_access_token_refresh_required_cb_t atrr_cb;
+    realm_user_get_sync_manager_cb_t sync_manager_cb;
+    realm_user_request_log_out_cb_t request_log_out_cb;
+    realm_user_request_refresh_location_cb_t request_refresh_location_cb;
+    realm_user_request_access_token_cb_t request_access_token_cb;
+    realm_user_track_realm_cb_t track_realm_cb;
+    realm_user_create_file_action_cb_t create_fa_cb;
+} realm_sync_user_create_config_t;
+
+/*
+ * Construct a SyncUser instance that uses SDK provided
+ * callbacks instead of core's User implementation. This type
+ * of user should not be used with core's App implementation.
+ */
+RLM_API realm_user_t* realm_user_new(realm_sync_user_create_config_t config) RLM_API_NOEXCEPT;
+
+/**
+ * Create realm_sync_manager_t* instance given a valid realm sync client configuration.
+ *
+ * @return A non-null pointer if no error occurred.
+ */
+RLM_API realm_sync_manager_t* realm_sync_manager_create(const realm_sync_client_config_t*);
+
+/**
+ * See SyncManager::set_sync_route()
+ */
+RLM_API void realm_sync_manager_set_route(const realm_sync_manager_t* session, const char* route, bool is_verified);
+
+
+#endif // !REALM_APP_SERVICES
+
 // This type should never be returned from a function.
 // It's only meant as an asynchronous callback argument.
 // Pointers to this struct and its pointer members are only valid inside the scope