SoW-2020-0002: Trace Hit Counters: trigger error reporting integration

[lttng-tools.git] / src / common / optional.h

diff --git a/src/common/optional.h b/src/common/optional.h
index 1da5fda5da21ac0e8d9acd9c4b7f9f3821b950a9..ca7d1f043d21bdef1b9ad8dc716452ee49fe7858 100644 (file)
--- a/src/common/optional.h
+++ b/src/common/optional.h
@@ -1,18 +1,8 @@
 /*
- * Copyright (C) 2019 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ * Copyright (C) 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License, version 2 only,
- * as published by the Free Software Foundation.
+ * SPDX-License-Identifier: GPL-2.0-only
  *
- * 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, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
 #ifndef LTTNG_OPTIONAL_H
@@ -32,9 +22,6 @@
  * Prefer using this macro where "special" values would be used, e.g.
  * -1ULL for uint64_t types.
  *
- * LTTNG_OPTIONAL should be combined with the LTTNG_PACKED macro when
- * used for IPC / network communication.
- *
  * Declaration example:
  * struct my_struct {
  *     int a;
@@ -57,6 +44,16 @@
                type value;  \
        }
 
+/*
+ * Alias used for communication structures. If the layout of an LTTNG_OPTIONAL
+ * is changed, the original layout should still be used for communication
+ * purposes.
+ *
+ * LTTNG_OPTIONAL_COMM should be combined with the LTTNG_PACKED macro when
+ * used for IPC / network communication.
+ */
+#define LTTNG_OPTIONAL_COMM LTTNG_OPTIONAL
+
 /*
  * This macro is available as a 'convenience' to allow sites that assume
  * an optional value is set to assert() that it is set when accessing it.
@@ -65,26 +62,46 @@
  * wrapped optional types. It is meant to be used with PODs.
  */
 #define LTTNG_OPTIONAL_GET(optional)                   \
-        ({                                             \
-               assert(optional.is_set);                \
-               optional.value;                         \
+       ({                                              \
+               assert((optional).is_set);              \
+               (optional).value;                       \
        })
 
 /*
- * Initialize an optional field.
+ * This macro is available as a 'convenience' to allow sites that assume
+ * an optional value is set to assert() that it is set when fecthing the
+ * underlying value's address.
+ */
+#define LTTNG_OPTIONAL_GET_PTR(optional)                       \
+       ({                                              \
+               assert((optional).is_set);              \
+               &(optional).value;                      \
+       })
+
+/*
+ * Initialize an optional field as unset.
  *
  * The wrapped field is set to the value it would gave if it had static storage
  * duration.
  */
-#define LTTNG_OPTIONAL_INIT { .is_set = 0 }
+#define LTTNG_OPTIONAL_INIT_UNSET { .is_set = 0 }
+
+/*
+ * Initialize an optional field as 'set' with a given value.
+ */
+#define LTTNG_OPTIONAL_INIT_VALUE(val) { .value = val, .is_set = 1 }
 
 /* Set the value of an optional field. */
-#define LTTNG_OPTIONAL_SET(field_ptr, val) \
-       (field_ptr)->value = val;          \
-       (field_ptr)->is_set = 1;
+#define LTTNG_OPTIONAL_SET(field_ptr, val)     \
+       do {                                    \
+               (field_ptr)->value = (val);     \
+               (field_ptr)->is_set = 1;        \
+       } while (0)
 
 /* Put an optional field in the "unset" (NULL-ed) state. */
-#define LTTNG_OPTIONAL_UNSET(field_ptr)    \
-       (field_ptr)->is_set = 0;
+#define LTTNG_OPTIONAL_UNSET(field_ptr)                \
+       do {                                    \
+               (field_ptr)->is_set = 0;        \
+       } while (0)
 
 #endif /* LTTNG_OPTIONAL_H */