DP: Introduce new interface for backend

Terminology:
* Backend: Implemenation of domain
* Data Provider: interface between backend and responders
* Module: ldap/ipa/ad/... dlopened library that implements dp interface
* Target: id/autofs/sudo/... functionality of module

Benefits over current code:
* data provider is a black box completely separated from backend
* method handlers are just simple tevent requests on backend side
* no need of spy on be_client
* simplified and error proof adding of new responders
* simplified adding of new methods
* reply to D-Bus message is completely handled by DP code
* each target can have several methods defined
* properties can be added on objects
* each method can have output parameters
* modules now support constructor
* improved debugging
* clear memory hierarchy
* ability to chain requests
* type safe private data

Reviewed-by: Sumit Bose <sbose@redhat.com>
Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
Reviewed-by: Lukáš Slebodník <lslebodn@redhat.com>

1 files changed, 77 insertions, 0 deletions

diff --git a/src/providers/data_provider/dp_request.h b/src/providers/data_provider/dp_request.h
new file mode 100644
index 000000000..361ab2536
--- /dev/null
+++ b/src/providers/data_provider/dp_request.h
@@ -0,0 +1,77 @@
+/*
+    Authors:
+        Pavel Březina <pbrezina@redhat.com>
+
+    Copyright (C) 2016 Red Hat
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef _DP_REQUEST_H_
+#define _DP_REQUEST_H_
+
+#include <talloc.h>
+
+#include "providers/data_provider/dp.h"
+
+struct data_provider;
+struct dp_client;
+enum dp_targets;
+enum dp_methods;
+
+struct tevent_req *dp_req_send(TALLOC_CTX *mem_ctx,
+                               struct data_provider *provider,
+                               struct dp_client *dp_cli,
+                               const char *domain,
+                               const char *name,
+                               enum dp_targets target,
+                               enum dp_methods method,
+                               uint32_t dp_flags,
+                               void *request_data,
+                               const char **_request_name);
+
+errno_t _dp_req_recv(TALLOC_CTX *mem_ctx,
+                     struct tevent_req *req,
+                     const char *data_type,
+                     void **_data);
+
+/**
+ * Returns value of output data.
+ *
+ * @example
+ *     struct dp_reply_std reply;
+ *     ret = dp_req_recv(mem_ctx, req, struct dp_reply_std, &reply);
+ */
+#define dp_req_recv(mem_ctx, req, data_type, _data)                        \
+({                                                                         \
+    data_type *__value = NULL;                                             \
+    errno_t __ret;                                                         \
+    __ret = _dp_req_recv(mem_ctx, req, #data_type, (void**)&__value);      \
+    if (__ret == EOK) {                                                    \
+        *(_data) = *__value;                                               \
+    }                                                                      \
+    __ret;                                                                 \
+})
+
+/**
+ * Returns pointer to output data type.
+ *
+ * @example
+ *     struct dp_reply_std *reply;
+ *     ret = dp_req_recv_ptr(mem_ctx, req, struct dp_reply_std, &reply);
+ */
+#define dp_req_recv_ptr(mem_ctx, req, data_type, _data) \
+    _dp_req_recv(mem_ctx, req, #data_type, (void**)_data)
+
+#endif /* _DP_REQUEST_H_ */