simple reference counting shared pointer

Signed-off-by: Cedric Roux <cedric.roux@eurecom.fr>

common/utils/ds/CMakeLists.txt

@@ -7,6 +7,7 @@ add_library(ds OBJECT
             hashtable.c
             obj_hashtable.c
             spsc_q.c
+            shared_pointer.c
 )
 
 target_include_directories(ds PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})

common/utils/ds/shared_pointer.c

@@ -0,0 +1,56 @@
+/*
+ * SPDX-License-Identifier: LicenseRef-CSSL-1.0
+ */
+
+#include "shared_pointer.h"
+#include "common/utils/utils.h"
+
+#define fatal(x, ...) do { \
+    if (!(x)) { \
+      fprintf(stderr, __VA_ARGS__); \
+      fflush(stderr); \
+      exit(1); \
+    } \
+  } while (0)
+
+static void lock(shared_pointer_t *p)
+{
+  fatal(pthread_mutex_lock(&p->m) == 0, "pthread_mutex_lock failed\n");
+}
+
+static void unlock(shared_pointer_t *p)
+{
+  fatal(pthread_mutex_unlock(&p->m) == 0, "pthread_mutex_unlock failed\n");
+}
+
+shared_pointer_t *new_shared_pointer(void *p, void (*free)(void *p))
+{
+  shared_pointer_t *s = malloc_or_fail(sizeof(*s));
+  s->p = p;
+  s->free = free;
+  s->count = 1;
+  pthread_mutex_init(&s->m, NULL);
+  return s;
+}
+
+void unref_shared_pointer(shared_pointer_t *p)
+{
+  lock(p);
+  fatal(p->count, "unref_shared_pointer() called for a pointer with count == 0\n");
+  p->count--;
+  if (p->count) {
+    unlock(p);
+    return;
+  }
+  unlock(p);
+  p->free(p->p);
+  free(p);
+}
+
+void ref_shared_pointer(shared_pointer_t *p)
+{
+  lock(p);
+  fatal(p->count, "ref_shared_pointer() called for a pointer with count == 0\n");
+  p->count++;
+  unlock(p);
+}

common/utils/ds/shared_pointer.h

@@ -0,0 +1,21 @@
+/*
+ * SPDX-License-Identifier: LicenseRef-CSSL-1.0
+ */
+
+#ifndef COMMON_UTILS_DS_SHARED_POINTER_H
+#define COMMON_UTILS_DS_SHARED_POINTER_H
+
+#include <pthread.h>
+
+typedef struct {
+  void *p;
+  void (*free)(void *p);
+  int count;
+  pthread_mutex_t m;
+} shared_pointer_t;
+
+shared_pointer_t *new_shared_pointer(void *p, void (*free)(void *p));
+void unref_shared_pointer(shared_pointer_t *p);
+void ref_shared_pointer(shared_pointer_t *p);
+
+#endif /* COMMON_UTILS_DS_SHARED_POINTER_H */

common/utils/ds/tests/test_seq_array.c

@@ -7,6 +7,16 @@
 #include "../../alg/foreach.h"
 #include <assert.h>
 
+/* needed because shared_pointer.c is using DevAssert() and AssertFatal() */
+void exit_function(const char *file, const char *function, const int line, const char *s, const int assert)
+{
+  if (assert) {
+    abort();
+  } else {
+    exit(EXIT_SUCCESS);
+  }
+}
+
 /*
   Example to show seq_arr_t capabilities and usage
   To compile: gcc test_seq_array.c ../seq_arr.c  ../../alg/find.c ../../alg/foreach.c

common/utils/time_manager/tests/CMakeLists.txt

@@ -6,7 +6,7 @@ target_link_libraries(test_time_manager_manual LOG CONFIG_LIB)
 
 add_executable(test_time_manager_auto test_auto.c)
 target_link_libraries(test_time_manager_auto time_management)
-target_link_libraries(test_time_manager_auto LOG CONFIG_LIB)
+target_link_libraries(test_time_manager_auto LOG CONFIG_LIB ds)
 
 add_dependencies(tests test_time_manager_auto)
 add_test(NAME time_management_tests