lib/object.h: log conditionally to `BT_OBJECT_DONT_LOG` undefined

There are a few places within the project, but outside the library, that
for historic reasons use the library's internal `bt_object` API to have
reference counting. The `bt_object` API belongs to the library for the
moment and should not be included as such.

There's an issue when you need logging in your module and the functions
which log within `object.h` cannot make sense of the
`BT_LOG_OUTPUT_LEVEL` expression. To avoid this and save short-term
development time, make them not log if `BT_OBJECT_DONT_LOG` is defined.
Then, outside the library, you can do something like:

    #define BT_LOG_OUTPUT_LEVEL my_log_level
    #define BT_LOG_TAG MY-TAG
    #include "logging/log.h"

    #define BT_OBJECT_DONT_LOG
    #include "lib/object.h"

Another solution would be to include `lib/logging.h` before
`logging/log.h`, but that's not always easy.

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Change-Id: If3037b67e5c4f87f57db96528d0a9516c8f9d6ea
Reviewed-on: https://review.lttng.org/c/babeltrace/+/1493
Tested-by: jenkins <jenkins@lttng.org>
Reviewed-by: Francis Deslauriers <francis.deslauriers@efficios.com>

diff --git a/src/lib/object.h b/src/lib/object.h
index 61a502f4254f1a98855c86e30cce553e161922b9..b8cb33bfdf7c673450c604cf79832f2415f5aac0 100644 (file)
--- a/src/lib/object.h
+++ b/src/lib/object.h
@@ -28,6 +28,18 @@
 #include "common/assert.h"
 #include <stdbool.h>
 
+/*
+ * Some parts of the Babeltrace project use this internal library header
+ * for internal reference counting. Until we make this header generic
+ * for the whole project, make it possible to disable logging in this
+ * file by defining `BT_OBJECT_DONT_LOG` because it's possible that the
+ * BT_LOGV() statements here won't find the log level
+ * (`BT_LOG_OUTPUT_LEVEL`).
+ */
+#if defined(BT_LOGV) && !defined(BT_OBJECT_DONT_LOG)
+# define _BT_OBJECT_LOGGING_ENABLED
+#endif
+
 struct bt_object;
 
 typedef void (*bt_object_release_func)(struct bt_object *);
@@ -126,7 +138,7 @@ void bt_object_set_parent(struct bt_object *child, struct bt_object *parent)
        BT_ASSERT(child);
        BT_ASSERT(child->is_shared);
 
-#ifdef BT_LOGV
+#ifdef _BT_OBJECT_LOGGING_ENABLED
        BT_LOGV("Setting object's parent: addr=%p, parent-addr=%p",
                child, parent);
 #endif
@@ -173,7 +185,7 @@ void bt_object_with_parent_release_func(struct bt_object *obj)
                 */
                struct bt_object *parent = obj->parent;
 
-#ifdef BT_LOGV
+#ifdef _BT_OBJECT_LOGGING_ENABLED
                BT_LOGV("Releasing parented object: addr=%p, ref-count=%llu, "
                        "parent-addr=%p, parent-ref-count=%llu",
                        obj, obj->ref_count,
@@ -263,7 +275,7 @@ void bt_object_get_no_null_check_no_parent_check(const struct bt_object *c_obj)
        BT_ASSERT(obj);
        BT_ASSERT(obj->is_shared);
 
-#ifdef BT_LOGV
+#ifdef _BT_OBJECT_LOGGING_ENABLED
        BT_LOGV("Incrementing object's reference count: %llu -> %llu: "
                "addr=%p, cur-count=%llu, new-count=%llu",
                obj->ref_count, obj->ref_count + 1,
@@ -282,7 +294,7 @@ void bt_object_get_no_null_check(const void *c_obj)
        BT_ASSERT(obj->is_shared);
 
        if (G_UNLIKELY(obj->parent && bt_object_get_ref_count(obj) == 0)) {
-#ifdef BT_LOGV
+#ifdef _BT_OBJECT_LOGGING_ENABLED
                BT_LOGV("Incrementing object's parent's reference count: "
                        "addr=%p, parent-addr=%p", obj, obj->parent);
 #endif
@@ -290,7 +302,7 @@ void bt_object_get_no_null_check(const void *c_obj)
                bt_object_get_no_null_check(obj->parent);
        }
 
-#ifdef BT_LOGV
+#ifdef _BT_OBJECT_LOGGING_ENABLED
        BT_LOGV("Incrementing object's reference count: %llu -> %llu: "
                "addr=%p, cur-count=%llu, new-count=%llu",
                obj->ref_count, obj->ref_count + 1,
@@ -309,7 +321,7 @@ void bt_object_put_no_null_check(const void *c_obj)
        BT_ASSERT(obj->is_shared);
        BT_ASSERT(obj->ref_count > 0);
 
-#ifdef BT_LOGV
+#ifdef _BT_OBJECT_LOGGING_ENABLED
        BT_LOGV("Decrementing object's reference count: %llu -> %llu: "
                "addr=%p, cur-count=%llu, new-count=%llu",
                obj->ref_count, obj->ref_count - 1,