Fix jerry_get_context_data() API function (#3127)

If manager_p->bytes_needed == 0, jerry_get_context_data() should return
NULL pointer. Additionally init_cb, deinit_cb and finalize_cb should be
called with NULL pointer in this case.

JerryScript-DCO-1.0-Signed-off-by: Csaba Osztrogonác oszi@inf.u-szeged.hu

Author: ossy-szeged

docs/02.API-REFERENCE.md

@@ -224,6 +224,7 @@ for the item by default, and if the `init_cb` field is not NULL, it will be call
 an additional custom initializer. The `deinit_cb` (if non-`NULL`) is called during a call to `jerry_cleanup ()` to run
 any custom deinitialization *before* the VM has been fully cleaned up. The `finalize_cb` (if non-`NULL`) is also called
 during a call to `jerry_cleanup ()` to run any custom deinitialization *after* the VM has been fully cleaned up.
+If bytes_needed field is 0, no buffer is allocated for the manager, callback functions are called with NULL pointer.
 
 **Prototype**
 

jerry-core/api/jerry.c

@@ -206,7 +206,8 @@ jerry_cleanup (void)
   {
     if (this_p->manager_p->deinit_cb)
     {
-      this_p->manager_p->deinit_cb (JERRY_CONTEXT_DATA_HEADER_USER_DATA (this_p));
+      void *data = (this_p->manager_p->bytes_needed > 0) ? JERRY_CONTEXT_DATA_HEADER_USER_DATA (this_p) : NULL;
+      this_p->manager_p->deinit_cb (data);
     }
   }
 
@@ -223,7 +224,8 @@ jerry_cleanup (void)
     next_p = this_p->next_p;
     if (this_p->manager_p->finalize_cb)
     {
-      this_p->manager_p->finalize_cb (JERRY_CONTEXT_DATA_HEADER_USER_DATA (this_p));
+      void *data = (this_p->manager_p->bytes_needed > 0) ? JERRY_CONTEXT_DATA_HEADER_USER_DATA (this_p) : NULL;
+      this_p->manager_p->finalize_cb (data);
     }
     jmem_heap_free_block (this_p, sizeof (jerry_context_data_header_t) + this_p->manager_p->bytes_needed);
   }
@@ -249,17 +251,21 @@ jerry_get_context_data (const jerry_context_data_manager_t *manager_p)
   {
     if (item_p->manager_p == manager_p)
     {
-      return JERRY_CONTEXT_DATA_HEADER_USER_DATA (item_p);
+      return (manager_p->bytes_needed > 0) ? JERRY_CONTEXT_DATA_HEADER_USER_DATA (item_p) : NULL;
     }
   }
 
   item_p = jmem_heap_alloc_block (sizeof (jerry_context_data_header_t) + manager_p->bytes_needed);
   item_p->manager_p = manager_p;
   item_p->next_p = JERRY_CONTEXT (context_data_p);
   JERRY_CONTEXT (context_data_p) = item_p;
-  ret = JERRY_CONTEXT_DATA_HEADER_USER_DATA (item_p);
 
-  memset (ret, 0, manager_p->bytes_needed);
+  if (manager_p->bytes_needed > 0)
+  {
+    ret = JERRY_CONTEXT_DATA_HEADER_USER_DATA (item_p);
+    memset (ret, 0, manager_p->bytes_needed);
+  }
+
   if (manager_p->init_cb)
   {
     manager_p->init_cb (ret);

tests/unit-core/test-context-data.c

@@ -20,9 +20,12 @@
 static bool test_context_data1_new_called = false;
 static bool test_context_data2_new_called = false;
 static bool test_context_data3_new_called = false;
+static bool test_context_data4_new_called = false;
 static bool test_context_data1_free_called = false;
 static bool test_context_data2_free_called = false;
+static bool test_context_data4_free_called = false;
 static bool test_context_data1_finalize_called = false;
+static bool test_context_data4_finalize_called = false;
 
 /* Context item 1 */
 const char *string1 = "item1";
@@ -84,13 +87,12 @@ static const jerry_context_data_manager_t manager2 =
 };
 
 /* Context item 3 */
-const char *string3 = "item3";
 
 static void
 test_context_data3_new (void *user_data_p)
 {
+  JERRY_UNUSED (user_data_p);
   test_context_data3_new_called = true;
-  *((const char **) user_data_p) = string3;
 } /* test_context_data3_new */
 
 static const jerry_context_data_manager_t manager3 =
@@ -102,6 +104,41 @@ static const jerry_context_data_manager_t manager3 =
   .bytes_needed = 0,
 };
 
+/* Context item 4 */
+
+static void
+test_context_data4_new (void *user_data_p)
+{
+  test_context_data4_new_called = true;
+  TEST_ASSERT (user_data_p == NULL);
+} /* test_context_data4_new */
+
+
+static void
+test_context_data4_free (void *user_data_p)
+{
+  test_context_data4_free_called = true;
+  TEST_ASSERT (user_data_p == NULL);
+  TEST_ASSERT (!test_context_data4_finalize_called);
+} /* test_context_data4_free */
+
+static void
+test_context_data4_finalize (void *user_data_p)
+{
+  TEST_ASSERT (!test_context_data4_finalize_called);
+  test_context_data4_finalize_called = true;
+  TEST_ASSERT (user_data_p == NULL);
+} /* test_context_data4_finalize */
+
+static const jerry_context_data_manager_t manager4 =
+{
+  .init_cb = test_context_data4_new,
+  .deinit_cb = test_context_data4_free,
+  .finalize_cb = test_context_data4_finalize,
+  .bytes_needed = 0
+};
+
+
 int
 main (void)
 {
@@ -111,19 +148,26 @@ main (void)
 
   TEST_ASSERT (!strcmp (*((const char **) jerry_get_context_data (&manager1)), "item1"));
   TEST_ASSERT (!strcmp (*((const char **) jerry_get_context_data (&manager2)), "item2"));
-  TEST_ASSERT (!strcmp (*((const char **) jerry_get_context_data (&manager3)), "item3"));
+  TEST_ASSERT (jerry_get_context_data (&manager3) == NULL);
+  TEST_ASSERT (jerry_get_context_data (&manager4) == NULL);
 
   TEST_ASSERT (test_context_data1_new_called);
   TEST_ASSERT (test_context_data2_new_called);
   TEST_ASSERT (test_context_data3_new_called);
+  TEST_ASSERT (test_context_data4_new_called);
 
   TEST_ASSERT (!test_context_data1_free_called);
   TEST_ASSERT (!test_context_data2_free_called);
+  TEST_ASSERT (!test_context_data4_free_called);
 
   jerry_cleanup ();
 
   TEST_ASSERT (test_context_data1_free_called);
   TEST_ASSERT (test_context_data2_free_called);
+  TEST_ASSERT (test_context_data4_free_called);
+
+  TEST_ASSERT (test_context_data1_finalize_called);
+  TEST_ASSERT (test_context_data4_finalize_called);
 
   return 0;
 } /* main */