Re-wrote xenDomainLookupByID to use more efficient XenD access

ChangeLog

@@ -1,8 +1,16 @@
+Fri Jul  7 09:47:14 EDT 2006 Daniel Berrange <berrange@redhat.com>
+	* src/xend_internal.c: changed xenDaemonLookupByID to simply do
+	an sexpr GET on /xend/domain/[ID] instead of listing all names
+	and iterating over /xend/domain/[NAME]. Reduces the running time
+	and number of GETs from O(n^2) to O(n).
+
+	* src/xend_internal.c: fixed xenDaemonOpen() to try both unix and
+
 Wed Jul  5 17:11:32 IST 2006 Mark McLoughlin <markmc@redhat.com>
 
 	* xml.c: allow a <domain> to not have any <disk> devices - e.g.
 	when using an NFS root.
-	
+
 Thu Jul  6 10:32:14 CEST 2006 Daniel Veillard <veillard@redhat.com>
 
 	* src/xend_internal.c: fixed xenDaemonOpen() to try both unix and

proxy/libvirt_proxy.c

@@ -454,33 +454,14 @@ retry2:
 	    }
 	    break;
 	case VIR_PROXY_LOOKUP_ID: {
-	    char **names;
-	    char **tmp;
-	    int ident, len;
 	    char *name = NULL;
 	    unsigned char uuid[16];
+	    int len;
 
 	    if (req->len != sizeof(virProxyPacket))
 	        goto comm_error;
 
-	    /*
-	     * Xend API forces to collect the full domain list by names, and
-             * then query each of them until the id is found
-	     */
-	    names = xenDaemonListDomainsOld(conn);
-	    tmp = names;
-
-	    if (names != NULL) {
-	       while (*tmp != NULL) {
-		  ident = xenDaemonDomainLookupByName_ids(conn, *tmp, &uuid[0]);
-		  if (ident == req->data.arg) {
-		     name = *tmp;
-		     break;
-		  }
-		  tmp++;
-	       }
-	    }
-            if (name == NULL) {
+	    if (xenDaemonDomainLookupByID(conn, req->data.arg, &name, uuid) < 0) {
                 req->data.arg = -1;
             } else {
 	        len = strlen(name);
@@ -492,7 +473,8 @@ retry2:
 		memcpy(&request.extra.str[0], uuid, 16);
 		strcpy(&request.extra.str[16], name);
 	    }
-	    free(names);
+	    if (name)
+	        free(name);
 	    break;
 	}
 	case VIR_PROXY_LOOKUP_UUID: {

src/xend_internal.c

@@ -1082,7 +1082,7 @@ xenDaemonDomainCreateLinux(virConnectPtr xend, const char *sexpr)
  */
 int
 xenDaemonDomainLookupByName_ids(virConnectPtr xend, const char *domname,
-                    unsigned char *uuid)
+				unsigned char *uuid)
 {
     struct sexpr *root;
     const char *value;
@@ -1119,6 +1119,62 @@ xenDaemonDomainLookupByName_ids(virConnectPtr xend, const char *domname,
     return (ret);
 }
 
+
+/**
+ * xenDaemonDomainLookupByID:
+ * @xend: A xend instance
+ * @id: The id of the domain
+ * @name: return value for the name if not NULL
+ * @uuid: return value for the UUID if not NULL
+ *
+ * This method looks up the name of a domain based on its id
+ *
+ * Returns the 0 on success; -1 (with errno) on error
+ */
+int
+xenDaemonDomainLookupByID(virConnectPtr xend,
+			  int id,
+			  char **domname,
+			  unsigned char *uuid)
+{
+    const char *name = NULL;
+    char *dst_uuid;
+    struct sexpr *root;
+
+    memset(uuid, 0, 16);
+
+    root = sexpr_get(xend, "/xend/domain/%d?detail=1", id);
+    if (root == NULL)
+      goto error;
+
+    name = sexpr_node(root, "domain/name");
+    if (name == NULL) {
+      virXendError(xend, VIR_ERR_INTERNAL_ERROR,
+                   "domain informations incomplete, missing name");
+      goto error;
+    }
+    if (domname)
+      *domname = strdup(name);
+
+    dst_uuid = (char *)&uuid[0];
+    if (sexpr_uuid(&dst_uuid, root, "domain/uuid") == NULL) {
+      virXendError(xend, VIR_ERR_INTERNAL_ERROR,
+                   "domain informations incomplete, missing uuid");
+      goto error;
+    }
+
+    sexpr_free(root);
+    return (0);
+
+error:
+    sexpr_free(root);
+    if (domname && *domname) {
+      free(*domname);
+      *domname = NULL;
+    }
+    return (-1);
+}
+
 /**
  * xend_get_node:
  * @xend: A xend instance
@@ -2264,33 +2320,13 @@ error:
  */
 static virDomainPtr
 xenDaemonLookupByID(virConnectPtr conn, int id) {
-    char **names;
-    char **tmp;
-    int ident;
     char *name = NULL;
     unsigned char uuid[16];
     virDomainPtr ret;
 
-    /*
-     * Xend API forces to collect the full domain list by names, and then
-     * query each of them until the id is found
-     */
-    names = xenDaemonListDomainsOld(conn);
-    tmp = names;
-
-    if (names != NULL) {
-       while (*tmp != NULL) {
-          ident = xenDaemonDomainLookupByName_ids(conn, *tmp, &uuid[0]);
-          if (ident == id) {
-             name = strdup(*tmp);
-             break;
-          }
-          tmp++;
-       }
-       free(names);
-    }
-    if (name == NULL)
+    if (xenDaemonDomainLookupByID(conn, id, &name, uuid) < 0) {
         goto error;
+    }
 
     ret = virGetDomain(conn, name, uuid);
     if (ret == NULL) {
@@ -2298,13 +2334,12 @@ xenDaemonLookupByID(virConnectPtr conn, int id) {
         goto error;
     }
     ret->handle = id;
-    if (name != NULL)
-        free(name);
+    free(name);
     return (ret);
 
-error:
+ error:
     if (name != NULL)
-        free(name);
+      free(name);
     return (NULL);
 }
 

src/xend_internal.h

@@ -534,6 +534,20 @@ int xenDaemonDomainLookupByName_ids(virConnectPtr xend,
                             const char *name, unsigned char *uuid);
 
 
+/**
+ * \brief Lookup the name of a domain
+ * \param xend A xend instance
+ * \param id The id of the domain
+ * \param name pointer to store a copy of the name
+ * \param uuid pointer to store a copy of the uuid
+ *
+ * This method looks up the name/uuid of a domain
+ */
+int xenDaemonDomainLookupByID(virConnectPtr xend,
+			      int id,
+			      char **name, unsigned char *uuid);
+
+
 /**
  * \brief Lookup information about the host machine
  * \param xend A xend instance