Add linkhash accessor functions (lh_table_head(), lh_entry_next(), etc...) to pave the way for making the lh_table and lh_entry structure opaque in the future.

Update the docs to mark all members of those structures deprecated, and
 suggest what to use instead.

ChangeLog

@@ -4,9 +4,11 @@ Next Release 0.16
 
 Significant changes and bug fixes
 ---------------------------------
-* Introduction of constant JSON_C_OBJECT_ADD_CONSTANT_KEY
+* Introduce constant JSON_C_OBJECT_ADD_CONSTANT_KEY
    as a replacement of JSON_C_OBJECT_KEY_IS_CONSTANT,
    JSON_C_OBJECT_KEY_IS_CONSTANT becoming legacy.
+* Direct access to lh_table and lh_entry structure members is deprecated.  
+  Use access functions instead, lh_table_head(), lh_entry_next(), etc...
 * Drop REFCOUNT_DEBUG code.
 
 ***

doc/Doxyfile.in

@@ -427,7 +427,7 @@ EXTRACT_PACKAGE        = NO
 # included in the documentation.
 # The default value is: NO.
 
-EXTRACT_STATIC         = NO
+EXTRACT_STATIC         = YES
 
 # If the EXTRACT_LOCAL_CLASSES tag is set to YES classes (and structs) defined
 # locally in source files will be included in the documentation. If set to NO
@@ -1984,7 +1984,9 @@ INCLUDE_FILE_PATTERNS  =
 # recursively expanded use the := operator instead of the = operator.
 # This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
 
-PREDEFINED             = THIS_FUNCTION_IS_DEPRECATED(f)=f
+PREDEFINED             = \
+	_LH_INLINE=inline \
+	JSON_C_CONST_FUNCTION(func)=func
 
 # If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then this
 # tag can be used to specify a list of macro names that should be expanded. The

json_object.c

@@ -498,7 +498,7 @@ static int json_object_object_to_json_string(struct json_object *jso, struct pri
 
 static void json_object_lh_entry_free(struct lh_entry *ent)
 {
-	if (!ent->k_is_constant)
+	if (!lh_entry_k_is_constant(ent))
 		free(lh_entry_k(ent));
 	json_object_put((struct json_object *)lh_entry_v(ent));
 }
@@ -569,7 +569,7 @@ int json_object_object_add_ex(struct json_object *jso, const char *const key,
 	existing_value = (json_object *)lh_entry_v(existing_entry);
 	if (existing_value)
 		json_object_put(existing_value);
-	existing_entry->v = val;
+	lh_entry_set_val(existing_entry, val);
 	return 0;
 }
 

json_object.h

@@ -483,14 +483,14 @@ JSON_EXPORT void json_object_object_del(struct json_object *obj, const char *key
 #define json_object_object_foreach(obj, key, val)                                \
 	char *key = NULL;                                                        \
 	struct json_object *val __attribute__((__unused__)) = NULL;              \
-	for (struct lh_entry *entry##key = json_object_get_object(obj)->head,    \
+	for (struct lh_entry *entry##key = lh_table_head(json_object_get_object(obj)),    \
 	                     *entry_next##key = NULL;                            \
 	     ({                                                                  \
 		     if (entry##key)                                             \
 		     {                                                           \
 			     key = (char *)lh_entry_k(entry##key);               \
 			     val = (struct json_object *)lh_entry_v(entry##key); \
-			     entry_next##key = entry##key->next;                 \
+			     entry_next##key = lh_entry_next(entry##key);        \
 		     };                                                          \
 		     entry##key;                                                 \
 	     });                                                                 \
@@ -503,10 +503,10 @@ JSON_EXPORT void json_object_object_del(struct json_object *obj, const char *key
 	struct json_object *val = NULL;                                        \
 	struct lh_entry *entry##key;                                           \
 	struct lh_entry *entry_next##key = NULL;                               \
-	for (entry##key = json_object_get_object(obj)->head;                   \
+	for (entry##key = lh_table_head(json_object_get_object(obj));          \
 	     (entry##key ? (key = (char *)lh_entry_k(entry##key),              \
 	                   val = (struct json_object *)lh_entry_v(entry##key), \
-	                   entry_next##key = entry##key->next, entry##key)     \
+	                   entry_next##key = lh_entry_next(entry##key), entry##key)     \
 	                 : 0);                                                 \
 	     entry##key = entry_next##key)
 
@@ -517,11 +517,11 @@ JSON_EXPORT void json_object_object_del(struct json_object *obj, const char *key
  * @param iter the object iterator, use type json_object_iter
  */
 #define json_object_object_foreachC(obj, iter)                                                  \
-	for (iter.entry = json_object_get_object(obj)->head;                                    \
+	for (iter.entry = lh_table_head(json_object_get_object(obj));                                    \
 	     (iter.entry ? (iter.key = (char *)lh_entry_k(iter.entry),                          \
 	                   iter.val = (struct json_object *)lh_entry_v(iter.entry), iter.entry) \
 	                 : 0);                                                                  \
-	     iter.entry = iter.entry->next)
+	     iter.entry = lh_entry_next(iter.entry))
 
 /* Array type methods */
 

json_object_iterator.c

@@ -71,7 +71,7 @@ struct json_object_iterator json_object_iter_begin(struct json_object *obj)
 
 	/// @note For a pair-less Object, head is NULL, which matches our
 	///       definition of the "end" iterator
-	iter.opaque_ = pTable->head;
+	iter.opaque_ = lh_table_head(pTable);
 	return iter;
 }
 
@@ -98,7 +98,7 @@ void json_object_iter_next(struct json_object_iterator *iter)
 	JASSERT(NULL != iter);
 	JASSERT(kObjectEndIterValue != iter->opaque_);
 
-	iter->opaque_ = ((const struct lh_entry *)iter->opaque_)->next;
+	iter->opaque_ = lh_entry_next(((const struct lh_entry *)iter->opaque_));
 }
 
 /**

linkhash.h

@@ -80,64 +80,84 @@ typedef unsigned long(lh_hash_fn)(const void *k);
 typedef int(lh_equal_fn)(const void *k1, const void *k2);
 
 /**
- * An entry in the hash table
+ * An entry in the hash table.  Outside of linkhash.c, treat this as opaque.
  */
 struct lh_entry
 {
 	/**
-	 * The key.  Use lh_entry_k() instead of accessing this directly.
+	 * The key.
+	 * @deprecated Use lh_entry_k() instead of accessing this directly.
 	 */
 	const void *k;
 	/**
 	 * A flag for users of linkhash to know whether or not they
 	 * need to free k.
+	 * @deprecated use lh_entry_k_is_constant() instead.
 	 */
 	int k_is_constant;
 	/**
-	 * The value.  Use lh_entry_v() instead of accessing this directly.
+	 * The value.
+	 * @deprecated Use lh_entry_v() instead of accessing this directly.
 	 */
 	const void *v;
 	/**
-	 * The next entry
+	 * The next entry.
+	 * @deprecated Use lh_entry_next() instead of accessing this directly.
 	 */
 	struct lh_entry *next;
 	/**
 	 * The previous entry.
+	 * @deprecated Use lh_entry_prev() instead of accessing this directly.
 	 */
 	struct lh_entry *prev;
 };
 
 /**
- * The hash table structure.
+ * The hash table structure.  Outside of linkhash.c, treat this as opaque.
  */
 struct lh_table
 {
 	/**
 	 * Size of our hash.
+	 * @deprecated do not use outside of linkhash.c
 	 */
 	int size;
 	/**
 	 * Numbers of entries.
+	 * @deprecated Use lh_table_length() instead.
 	 */
 	int count;
 
 	/**
 	 * The first entry.
+	 * @deprecated Use lh_table_head() instead.
 	 */
 	struct lh_entry *head;
 
 	/**
 	 * The last entry.
+	 * @deprecated Do not use, may be removed in a future release.
 	 */
 	struct lh_entry *tail;
 
+	/**
+	 * Internal storage of the actual table of entries.
+	 * @deprecated do not use outside of linkhash.c
+	 */
 	struct lh_entry *table;
 
 	/**
-	 * A pointer onto the function responsible for freeing an entry.
+	 * A pointer to the function responsible for freeing an entry.
+	 * @deprecated do not use outside of linkhash.c
 	 */
 	lh_entry_free_fn *free_fn;
+	/**
+	 * @deprecated do not use outside of linkhash.c
+	 */
 	lh_hash_fn *hash_fn;
+	/**
+	 * @deprecated do not use outside of linkhash.c
+	 */
 	lh_equal_fn *equal_fn;
 };
 typedef struct lh_table lh_table;
@@ -145,7 +165,7 @@ typedef struct lh_table lh_table;
 /**
  * Convenience list iterator.
  */
-#define lh_foreach(table, entry) for (entry = table->head; entry; entry = entry->next)
+#define lh_foreach(table, entry) for (entry = lh_table_head(table); entry; entry = lh_entry_next(entry))
 
 /**
  * lh_foreach_safe allows calling of deletion routine while iterating.
@@ -155,7 +175,7 @@ typedef struct lh_table lh_table;
  * @param tmp a struct lh_entry * variable to hold a temporary pointer to the next element
  */
 #define lh_foreach_safe(table, entry, tmp) \
-	for (entry = table->head; entry && ((tmp = entry->next) || 1); entry = tmp)
+	for (entry = lh_table_head(table); entry && ((tmp = lh_entry_next(entry)) || 1); entry = tmp)
 
 /**
  * Create a new linkhash table.
@@ -295,6 +315,9 @@ extern int lh_table_delete_entry(struct lh_table *t, struct lh_entry *e);
  */
 extern int lh_table_delete(struct lh_table *t, const void *k);
 
+/**
+ * Return the number of entries in the table.
+ */
 extern int lh_table_length(struct lh_table *t);
 
 /**
@@ -318,6 +341,15 @@ int lh_table_resize(struct lh_table *t, int new_size);
 #define _LH_INLINE inline
 #endif
 
+/**
+ * Return the first entry in the lh_table.
+ * @see lh_entry_next()
+ */
+static _LH_INLINE struct lh_entry *lh_table_head(const lh_table *t)
+{
+	return t->head;
+}
+
 /**
  * Calculate the hash of a key for a given table.
  *
@@ -334,7 +366,6 @@ static _LH_INLINE unsigned long lh_get_hash(const struct lh_table *t, const void
 	return t->hash_fn(k);
 }
 
-#undef _LH_INLINE
 
 /**
  * @deprecated Don't use this outside of linkhash.h:
@@ -350,9 +381,22 @@ static _LH_INLINE unsigned long lh_get_hash(const struct lh_table *t, const void
  *
  * lh_entry.k is const to indicate and help ensure that linkhash itself doesn't modify
  * it, but callers are allowed to do what they want with it.
- * See also lh_entry.k_is_constant
+ * @see lh_entry_k_is_constant()
+ */
+static _LH_INLINE void *lh_entry_k(const struct lh_entry *e)
+{
+	return _LH_UNCONST(e->k);
+}
+
+/**
+ * Returns 1 if the key for the given entry is constant, and thus
+ *  does not need to be freed when the lh_entry is freed.
+ * @see lh_table_insert_w_hash()
  */
-#define lh_entry_k(entry) _LH_UNCONST((entry)->k)
+static _LH_INLINE int lh_entry_k_is_constant(const struct lh_entry *e)
+{
+	return e->k_is_constant;
+}
 
 /**
  * Return a non-const version of lh_entry.v.
@@ -360,7 +404,41 @@ static _LH_INLINE unsigned long lh_get_hash(const struct lh_table *t, const void
  * v is const to indicate and help ensure that linkhash itself doesn't modify
  * it, but callers are allowed to do what they want with it.
  */
-#define lh_entry_v(entry) _LH_UNCONST((entry)->v)
+static _LH_INLINE void *lh_entry_v(const struct lh_entry *e)
+{
+	return _LH_UNCONST(e->v);
+}
+
+/**
+ * Change the value for an entry.  The caller is responsible for freeing
+ *  the previous value.
+ */
+static _LH_INLINE void lh_entry_set_val(struct lh_entry *e, void *newval)
+{
+	e->v = newval;
+}
+
+/**
+ * Return the next element, or NULL if there is no next element.
+ * @see lh_table_head()
+ * @see lh_entry_prev()
+ */
+static _LH_INLINE struct lh_entry *lh_entry_next(const struct lh_entry *e)
+{
+	return e->next;
+}
+
+/**
+ * Return the previous element, or NULL if there is no previous element.
+ * @see lh_table_head()
+ * @see lh_entry_next()
+ */
+static _LH_INLINE struct lh_entry *lh_entry_prev(const struct lh_entry *e)
+{
+	return e->prev;
+}
+
+#undef _LH_INLINE
 
 #ifdef __cplusplus
 }