lib: internal: add BT_ASSERT_POST()

[babeltrace.git] / src / lib / assert-post.h

diff --git a/src/lib/assert-post.h b/src/lib/assert-post.h
new file mode 100644 (file)
index 0000000..3e1a25d
--- /dev/null
+++ b/src/lib/assert-post.h
@@ -0,0 +1,115 @@
+#ifndef BABELTRACE_ASSERT_POST_INTERNAL_H
+#define BABELTRACE_ASSERT_POST_INTERNAL_H
+
+/*
+ * Copyright (c) 2019 EfficiOS Inc. and Linux Foundation
+ * Copyright (c) 2019 Philippe Proulx <pproulx@efficios.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+/*
+ * The macros in this header use macros defined in "lib/logging.h".
+ * We don't want this header to automatically include
+ * "lib/logging.h" because you need to manually define BT_LOG_TAG
+ * before including "lib/logging.h" and it is unexpected that you
+ * also need to define it before including this header.
+ *
+ * This is a reminder that in order to use "lib/assert-post.h", you also
+ * need to use logging explicitly.
+ */
+
+#ifndef BT_LIB_LOG_SUPPORTED
+# error Include "lib/logging.h" before this header.
+#endif
+
+#include <stdlib.h>
+#include <inttypes.h>
+#include "common/macros.h"
+
+#ifdef BT_DEV_MODE
+/*
+ * Prints the details of an unsatisfied postcondition without
+ * immediately aborting. You should use this within a function which
+ * checks postconditions, but which is called from a BT_ASSERT_POST()
+ * context, so that the function can still return its result for
+ * BT_ASSERT_POST() to evaluate it.
+ *
+ * Example:
+ *
+ *     BT_ASSERT_POST_FUNC
+ *     static inline bool check_complex_postcond(...)
+ *     {
+ *         ...
+ *
+ *         if (...) {
+ *             BT_ASSERT_POST_MSG("Unexpected status: ...", ...);
+ *             return false;
+ *         }
+ *
+ *         ...
+ *     }
+ *
+ *     ...
+ *
+ *     BT_ASSERT_POST(check_complex_postcond(...),
+ *                   "Postcondition is not satisfied: ...", ...);
+ */
+# define BT_ASSERT_POST_MSG(_fmt, ...)                                 \
+       do {                                                            \
+               bt_lib_log(_BT_LOG_SRCLOC_FUNCTION, __FILE__,           \
+                       __LINE__, BT_LOG_FATAL, BT_LOG_TAG,             \
+                       (_fmt), ##__VA_ARGS__);                         \
+       } while (0)
+
+/*
+ * Developer mode: asserts that the library postcondition `_cond` is
+ * satisfied.
+ *
+ * If `_cond` is false, log a fatal statement using `_fmt` and the
+ * optional arguments (same usage as BT_LIB_LOGF()), and abort.
+ *
+ * To assert that a library precondition is satisfied (parameters from
+ * the user), use BT_ASSERT_PRE().
+ *
+ * To assert that an internal postcondition is satisfied, use
+ * BT_ASSERT().
+ */
+# define BT_ASSERT_POST(_cond, _fmt, ...)                              \
+       do {                                                            \
+               if (!(_cond)) {                                         \
+                       BT_ASSERT_POST_MSG("Babeltrace 2 library postcondition not satisfied; error is:"); \
+                       BT_ASSERT_POST_MSG((_fmt), ##__VA_ARGS__);      \
+                       BT_ASSERT_POST_MSG("Aborting...");              \
+                       abort();                                        \
+               }                                                       \
+       } while (0)
+
+/*
+ * Marks a function as being only used within a BT_ASSERT_POST()
+ * context.
+ */
+# define BT_ASSERT_POST_FUNC
+#else
+# define BT_ASSERT_POST(_cond, _fmt, ...)      ((void) sizeof((void) (_cond), 0))
+# define BT_ASSERT_POST_FUNC   __attribute__((unused))
+# define BT_ASSERT_POST_MSG(_fmt, ...)
+#endif /* BT_DEV_MODE */
+
+#endif /* BABELTRACE_ASSERT_POST_INTERNAL_H */