Replace libxml2's xmlNode with a custom XML structure

The new structure (rexmpp_xml) is simpler, and should allow
manipulation from Rust without any dependency on libxml2 from the Rust
code (while Rust has its own parsers, such as rxml). Alternative XML
parsers (e.g., libexpat) now can be used from the C code.

The replacement/abstraction is not quite complete yet: the parsing
process itself (xmlParseChunk and friends) should be abstracted out.

1 files changed, 36 insertions, 40 deletions

diff --git a/src/rexmpp_roster.c b/src/rexmpp_roster.c
index 63a52b9..db09ff0 100644
--- a/src/rexmpp_roster.c
+++ b/src/rexmpp_roster.c
@@ -7,24 +7,25 @@
 */
 
 #include "rexmpp.h"
+#include "rexmpp_xml.h"
 #include <syslog.h>
 #include <string.h>
 #include <libxml/tree.h>
 #include <libxml/xmlsave.h>
 
-xmlNodePtr rexmpp_roster_find_item (rexmpp_t *s,
-                                    const char *jid,
-                                    xmlNodePtr *prev_item)
+rexmpp_xml_t *
+rexmpp_roster_find_item (rexmpp_t *s,
+                         const char *jid,
+                         rexmpp_xml_t **prev_item)
 {
-  xmlNodePtr prev = NULL, cur = s->roster_items;
+  rexmpp_xml_t *prev = NULL, *cur = s->roster_items;
   while (cur != NULL) {
-    char *cur_jid = xmlGetProp(cur, "jid");
+    const char *cur_jid = rexmpp_xml_find_attr_val(cur, "jid");
     if (cur_jid == NULL) {
       rexmpp_log(s, LOG_ALERT, "No jid found in a roster item.");
       return NULL;
     }
     int match = (strcmp(cur_jid, jid) == 0);
-    free(cur_jid);
     if (match) {
       if (prev_item != NULL) {
         *prev_item = prev;
@@ -37,17 +38,17 @@ xmlNodePtr rexmpp_roster_find_item (rexmpp_t *s,
   return NULL;
 }
 
-rexmpp_err_t rexmpp_modify_roster (rexmpp_t *s, xmlNodePtr item) {
+rexmpp_err_t rexmpp_modify_roster (rexmpp_t *s, rexmpp_xml_t *item) {
   rexmpp_err_t ret = REXMPP_SUCCESS;
   if (! rexmpp_xml_match(item, "jabber:iq:roster", "item")) {
     rexmpp_log(s, LOG_ERR, "No roster item.");
     return REXMPP_E_PARAM;
   }
-  char *subscription = xmlGetProp(item, "subscription");
-  char *jid = xmlGetProp(item, "jid");
+  const char *subscription = rexmpp_xml_find_attr_val(item, "subscription");
+  const char *jid = rexmpp_xml_find_attr_val(item, "jid");
   if (subscription != NULL && strcmp(subscription, "remove") == 0) {
     /* Delete the item. */
-    xmlNodePtr prev, cur;
+    rexmpp_xml_t *prev, *cur;
     cur = rexmpp_roster_find_item(s, jid, &prev);
     if (cur != NULL) {
       if (prev != NULL) {
@@ -55,13 +56,13 @@ rexmpp_err_t rexmpp_modify_roster (rexmpp_t *s, xmlNodePtr item) {
       } else {
         s->roster_items = cur->next;
       }
-      xmlFreeNode(cur);
+      rexmpp_xml_free(cur);
     } else {
       ret = REXMPP_E_ROSTER_ITEM_NOT_FOUND;
     }
   } else {
     /* Add or modify the item. */
-    xmlNodePtr cur, prev;
+    rexmpp_xml_t *cur, *prev;
     cur = rexmpp_roster_find_item(s, jid, &prev);
     /* Remove the item if it was in the roster before. */
     if (cur != NULL) {
@@ -70,37 +71,33 @@ rexmpp_err_t rexmpp_modify_roster (rexmpp_t *s, xmlNodePtr item) {
       } else {
         s->roster_items = cur->next;
       }
-      xmlFreeNode(cur);
+      rexmpp_xml_free(cur);
     }
     /* Add the new item. */
-    xmlNodePtr new_item = xmlCopyNode(item, 1);
+    rexmpp_xml_t *new_item = rexmpp_xml_clone(item);
     new_item->next = s->roster_items;
     s->roster_items = new_item;
   }
-  free(jid);
-  if (subscription != NULL) {
-    free(subscription);
-  }
   if (s->roster_modify_cb != NULL) {
     s->roster_modify_cb(s, item);
   }
   return ret;
 }
 
-void rexmpp_roster_set (rexmpp_t *s, xmlNodePtr query) {
+void rexmpp_roster_set (rexmpp_t *s, rexmpp_xml_t *query) {
   if (s->roster_items != NULL) {
-    xmlFreeNodeList(s->roster_items);
+    rexmpp_xml_free_list(s->roster_items);
   }
   if (s->roster_ver != NULL) {
     free(s->roster_ver);
   }
-  s->roster_ver = xmlGetProp(query, "ver");
-  s->roster_items = xmlCopyNodeList(xmlFirstElementChild(query));
+  s->roster_ver = strdup(rexmpp_xml_find_attr_val(query, "ver"));
+  s->roster_items = rexmpp_xml_clone_list(query->alt.elem.children);
   if (s->roster_modify_cb != NULL) {
-    xmlNodePtr item;
-    for (item = xmlFirstElementChild(query);
+    rexmpp_xml_t *item;
+    for (item = query->alt.elem.children;
          item != NULL;
-         item = xmlNextElementSibling(item))
+         item = item->next)
       {
         s->roster_modify_cb(s, item);
       }
@@ -112,10 +109,11 @@ void rexmpp_roster_cache_read (rexmpp_t *s) {
     rexmpp_log(s, LOG_WARNING, "No roster cache file path is set.");
     return;
   }
-  xmlDocPtr doc = xmlReadFile(s->roster_cache_file, "utf-8", XML_PARSE_NONET);
-  xmlNodePtr query = xmlDocGetRootElement(doc);
-  rexmpp_roster_set(s, query);
-  xmlFreeDoc(doc);
+  rexmpp_xml_t *query = rexmpp_xml_read_file(s->roster_cache_file);
+  if (query != NULL) {
+    rexmpp_roster_set(s, query);
+    rexmpp_xml_free(query);
+  }
 }
 
 void rexmpp_roster_cache_write (rexmpp_t *s) {
@@ -123,24 +121,22 @@ void rexmpp_roster_cache_write (rexmpp_t *s) {
     rexmpp_log(s, LOG_WARNING, "No roster cache file path is set.");
     return;
   }
-  xmlDocPtr doc = xmlNewDoc("1.0");
-  xmlNodePtr query = xmlNewDocNode(doc, NULL, "query", NULL);
-  xmlDocSetRootElement(doc, query);
-  xmlNewNs(query, "jabber:iq:roster", NULL);
+
+  rexmpp_xml_t *query = rexmpp_xml_new_elem("query", "jabber:iq:roster");
   if (s->roster_ver != NULL) {
-    xmlNewProp(query, "ver", s->roster_ver);
+    rexmpp_xml_add_attr(query, "ver", s->roster_ver);
   }
   if (s->roster_items != NULL) {
-    xmlAddChild(query, xmlDocCopyNodeList(doc, s->roster_items));
+    rexmpp_xml_add_child(query, rexmpp_xml_clone_list(s->roster_items));
   }
-  xmlSaveFileEnc(s->roster_cache_file, doc, "utf-8");
-  xmlFreeDoc(doc);
+  rexmpp_xml_write_file(s->roster_cache_file, query);
+  rexmpp_xml_free(query);
 }
 
 void rexmpp_iq_roster_get (rexmpp_t *s,
                            void *ptr,
-                           xmlNodePtr req,
-                           xmlNodePtr response,
+                           rexmpp_xml_t *req,
+                           rexmpp_xml_t *response,
                            int success)
 {
   (void)ptr;
@@ -149,7 +145,7 @@ void rexmpp_iq_roster_get (rexmpp_t *s,
     rexmpp_log(s, LOG_ERR, "Roster loading failed.");
     return;
   }
-  xmlNodePtr query = xmlFirstElementChild(response);
+  rexmpp_xml_t *query = response->alt.elem.children;
   if (! rexmpp_xml_match(query, "jabber:iq:roster", "query")) {
     rexmpp_log(s, LOG_DEBUG, "No roster query in reply.");
     return;