Bugfix: check context manager deinit callback for NULL before calling it (#2222)

The deinit_cb should be allowed to be NULL.

JerryScript-DCO-1.0-Signed-off-by: Martijn The martijn.the@intel.com

docs/02.API-REFERENCE.md

@@ -122,8 +122,9 @@ typedef uint32_t jerry_value_t;
 **Summary**
 
 Structure that defines how a context data item will be initialized and deinitialized. JerryScript zeroes out the memory
-for the item by default, and if the `init_cb` field is not NULL, it will be called with the pointer to the memory  as
-an additional custom initializer.
+for the item by default, and if the `init_cb` field is not NULL, it will be called with the pointer to the memory as
+an additional custom initializer. The `deinit_cb` (if non-`NULL`) is called during a call to `jerry_cleanup()` to run
+any custom deinitialization.
 
 **Prototype**
 
@@ -131,7 +132,7 @@ an additional custom initializer.
 typedef struct
 {
   void (*init_cb) (void *); /**< callback responsible for initializing a context item, or NULL */
-  void (*deinit_cb) (void *); /**< callback responsible for deinitializing a context item */
+  void (*deinit_cb) (void *); /**< callback responsible for deinitializing a context item, or NULL */
   size_t bytes_needed; /**< number of bytes to allocate for this manager */
 } jerry_context_data_manager_t;
 ```

jerry-core/api/jerry.c

@@ -215,7 +215,10 @@ jerry_cleanup (void)
        this_p = next_p)
   {
     next_p = this_p->next_p;
-    this_p->manager_p->deinit_cb (JERRY_CONTEXT_DATA_HEADER_USER_DATA (this_p));
+    if (this_p->manager_p->deinit_cb)
+    {
+      this_p->manager_p->deinit_cb (JERRY_CONTEXT_DATA_HEADER_USER_DATA (this_p));
+    }
     jmem_heap_free_block (this_p, sizeof (jerry_context_data_header_t) + this_p->manager_p->bytes_needed);
   }
 

jerry-core/include/jerryscript-core.h

@@ -217,7 +217,7 @@ typedef bool (*jerry_object_property_foreach_t) (const jerry_value_t property_na
 typedef struct
 {
   void (*init_cb) (void *); /**< callback responsible for initializing a context item, or NULL to zero out the memory */
-  void (*deinit_cb) (void *); /**< callback responsible for deinitializing a context item */
+  void (*deinit_cb) (void *); /**< callback responsible for deinitializing a context item, or NULL */
   size_t bytes_needed; /**< number of bytes to allocate for this manager */
 } jerry_context_data_manager_t;
 

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

@@ -21,6 +21,7 @@ static bool test_context_data1_new_called = false;
 static bool test_context_data2_new_called = false;
 static bool test_context_data1_free_called = false;
 static bool test_context_data2_free_called = false;
+static bool test_context_data3_new_called = false;
 
 /* Context item 1 */
 const char *string1 = "item1";
@@ -70,6 +71,24 @@ static const jerry_context_data_manager_t manager2 =
   .bytes_needed = sizeof (const char *)
 };
 
+/* Context item 3 */
+const char *string3 = "item3";
+
+static void
+test_context_data3_new (void *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 =
+{
+  .init_cb = test_context_data3_new,
+  /* NULL is allowed: */
+  .deinit_cb = NULL,
+  .bytes_needed = 0,
+};
+
 int
 main (void)
 {
@@ -79,9 +98,11 @@ 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 (test_context_data1_new_called);
   TEST_ASSERT (test_context_data2_new_called);
+  TEST_ASSERT (test_context_data3_new_called);
 
   TEST_ASSERT (!test_context_data1_free_called);
   TEST_ASSERT (!test_context_data2_free_called);