From 5a0a473c30925d63e1695a7b8b1cee8f73ad6e68 Mon Sep 17 00:00:00 2001
From: Yang Tse <yangsita@gmail.com>
Date: Fri, 20 Nov 2009 08:50:03 +0000
Subject: Initial support for the generic ares_free_data() function that will
 allow applications to free memory allocated and returned by some c-ares
 funtions.

---
 ares/ares_data.c | 142 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 142 insertions(+)
 create mode 100644 ares/ares_data.c

(limited to 'ares/ares_data.c')

diff --git a/ares/ares_data.c b/ares/ares_data.c
new file mode 100644
index 000000000..5d710ee65
--- /dev/null
+++ b/ares/ares_data.c
@@ -0,0 +1,142 @@
+/* $Id$ */
+
+/* Copyright (C) 2009 by Daniel Stenberg
+ *
+ * Permission to use, copy, modify, and distribute this
+ * software and its documentation for any purpose and without
+ * fee is hereby granted, provided that the above copyright
+ * notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting
+ * documentation, and that the name of M.I.T. not be used in
+ * advertising or publicity pertaining to distribution of the
+ * software without specific, written prior permission.
+ * M.I.T. makes no representations about the suitability of
+ * this software for any purpose.  It is provided "as is"
+ * without express or implied warranty.
+ */
+
+
+#include "ares_setup.h"
+
+#include <stddef.h>
+
+#include "ares.h"
+#include "ares_data.h"
+#include "ares_private.h"
+
+
+/*
+** ares_free_data() - c-ares external API function.
+**
+** This function must be used by the application to free data memory that
+** has been internally allocated by some c-ares function and for which a
+** pointer has already been returned to the calling application. The list
+** of c-ares functions returning pointers that must be free'ed using this
+** function is:
+**
+**   FIXME: specify function list.
+*/
+
+void ares_free_data(void *dataptr)
+{
+  struct ares_data *ptr;
+
+  if (!dataptr)
+    return;
+
+  ptr = (void *)((char *)dataptr - offsetof(struct ares_data, data));
+
+  if (ptr->mark != ARES_DATATYPE_MARK)
+    return;
+
+  switch (ptr->type)
+    {
+      case ARES_DATATYPE_SRV_REPLY:
+
+        if (ptr->data.srv_reply.next)
+          ares_free_data(ptr->data.srv_reply.next);
+        if (ptr->data.srv_reply.host)
+          free(ptr->data.srv_reply.host);
+        break;
+
+      case ARES_DATATYPE_TXT_REPLY:
+
+        if (ptr->data.txt_reply.next)
+          ares_free_data(ptr->data.txt_reply.next);
+        if (ptr->data.txt_reply.txt)
+          free(ptr->data.txt_reply.txt);
+        break;
+
+      default:
+        return;
+    }
+
+  free(ptr);
+}
+
+
+/*
+** ares_malloc_data() - c-ares internal helper function.
+**
+** This function allocates memory for a c-ares private ares_data struct
+** for the specified ares_datatype, initializes c-ares private fields
+** and zero initializes those which later might be used from the public
+** API. It returns an interior pointer which can be passed by c-ares
+** functions to the calling application, and that must be free'ed using
+** c-ares external API function ares_free_data().
+*/
+
+void *ares_malloc_data(ares_datatype type)
+{
+  struct ares_data *ptr;
+
+  ptr = malloc(sizeof(struct ares_data));
+  if (!ptr)
+    return NULL;
+
+  switch (type)
+    {
+      case ARES_DATATYPE_SRV_REPLY:
+        ptr->data.srv_reply.next = NULL;
+        ptr->data.srv_reply.host = NULL;
+        ptr->data.srv_reply.priority = 0;
+        ptr->data.srv_reply.weight = 0;
+        ptr->data.srv_reply.port = 0;
+        break;
+
+      case ARES_DATATYPE_TXT_REPLY:
+        ptr->data.txt_reply.next = NULL;
+        ptr->data.txt_reply.txt = NULL;
+        ptr->data.txt_reply.length  = 0;
+        break;
+
+      default:
+        free(ptr);
+        return NULL;
+    }
+
+  ptr->mark = ARES_DATATYPE_MARK;
+  ptr->type = type;
+
+  return &ptr->data;
+}
+
+
+/*
+** ares_get_datatype() - c-ares internal helper function.
+**
+** This function returns the ares_datatype of the data stored in a
+** private ares_data struct when given the public API pointer.
+*/
+
+ares_datatype ares_get_datatype(void * dataptr)
+{
+  struct ares_data *ptr;
+
+  ptr = (void *)((char *)dataptr - offsetof(struct ares_data, data));
+
+  if (ptr->mark == ARES_DATATYPE_MARK)
+    return ptr->type;
+
+  return ARES_DATATYPE_UNKNOWN;
+}
-- 
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