Generate a unique ID per message

Add a ID per message. Seems to fix the duplicate messages seen with MUCs
on the Conversations android client whenever the network is switched
(e.g., from wifi to cell).

Introduce a dependency on Linux's libuuid which introduces portability
issues. However, it should be simple to add support for the BSD UUID
interface.

libuuid was used because it is a fast and simple way of generating
a unique id.  Realistically, the ID only needs to be unique within
the MUC and so could probably be replaced with an sprintf() combining
time of day, PID and a random number.

Makefile

@@ -1,7 +1,7 @@
 RM=rm
 
 all:
-	$(CC) -g -Wall $(CFLAGS) -o xmppipe src/*.c $(LDFLAGS) -lstrophe
+	$(CC) -g -Wall $(CFLAGS) -o xmppipe src/*.c $(LDFLAGS) -lstrophe -luuid
 
 clean:
 	-@$(RM) xmppipe

src/xmppipe.c

@@ -145,7 +145,9 @@ main(int argc, char **argv)
         state->mucjid = xmppipe_mucjid(state->out, state->resource);
     }
 
-    encode_init();
+    if (xmppipe_encode_init() < 0)
+        errx(EXIT_FAILURE, "xmppipe_encode_init");
+
     xmpp_initialize();
 
     log = xmpp_get_default_logger(XMPP_LEVEL_DEBUG);
@@ -366,7 +368,7 @@ handle_stdin(xmppipe_state_t *state, int fd, char *buf, size_t len)
         if ((state->opt & XMPPIPE_OPT_DISCARD) && state->occupants == 0) {
             if (state->opt & XMPPIPE_OPT_DISCARD_TO_STDOUT) {
                 char *enc = NULL;
-                enc = encode(buf);
+                enc = xmppipe_encode(buf);
                 (void)printf("!:%s\n", enc);
                 free(enc);
             }
@@ -598,9 +600,9 @@ handle_presence(xmpp_conn_t * const conn, xmpp_stanza_t * const stanza,
     if (state->status == XMPPIPE_S_READY_AVAIL && state->occupants == 0)
         state->status = XMPPIPE_S_READY_EMPTY;
 
-    etype = encode(type);
-    efrom = encode(from);
-    eto = encode(to);
+    etype = xmppipe_encode(type);
+    efrom = xmppipe_encode(from);
+    eto = xmppipe_encode(to);
 
     (void)printf("p:%s:%s:%s\n", etype, efrom, eto);
     state->interval = 0;
@@ -687,9 +689,9 @@ handle_message(xmpp_conn_t * const conn, xmpp_stanza_t * const stanza,
     if (!message)
         return 1;
 
-    etype = encode(type);
-    efrom = encode(from);
-    emessage = encode(message);
+    etype = xmppipe_encode(type);
+    efrom = xmppipe_encode(from);
+    emessage = xmppipe_encode(message);
 
     (void)printf("m:%s:%s:%s\n", etype, efrom, emessage);
     state->interval = 0;
@@ -782,11 +784,15 @@ xmppipe_send_message(xmppipe_state_t *state, char *to, char *type, char *buf)
     xmpp_stanza_t *message = NULL;
     xmpp_stanza_t *body = NULL;
     xmpp_stanza_t *text = NULL;
+    char *id = NULL;
+
+    id = xmppipe_id_alloc();
 
     message = xmpp_stanza_new(state->ctx);
     xmpp_stanza_set_name(message, "message");
     xmpp_stanza_set_type(message, type);
     xmpp_stanza_set_attribute(message, "to", to);
+    xmpp_stanza_set_id(message, id);
 
     body = xmpp_stanza_new(state->ctx);
     xmpp_stanza_set_name(body, "body");
@@ -799,6 +805,7 @@ xmppipe_send_message(xmppipe_state_t *state, char *to, char *type, char *buf)
 
     xmpp_send(state->conn, message);
     xmpp_stanza_release(message);
+    free(id);
 }
 
     void

src/xmppipe.h

@@ -73,8 +73,9 @@ typedef struct {
 } xmppipe_state_t;
 
 
-void encode_init();
-char *encode(const char *);
+int xmppipe_encode_init();
+char *xmppipe_encode(const char *);
+char *xmppipe_id_alloc();
 int xmppipe_set_nonblock(int fd);
 
 char *xmppipe_servername(char *);

src/xmppipe_encode.c

@@ -16,17 +16,19 @@
 
 static unsigned char rfc3986[256];
 
-    void
-encode_init()
+    int
+xmppipe_encode_init()
 {
     int i = 0;
 
     for (i = 0; i < 256; i++)
         rfc3986[i] = isalnum(i) || i == '~' || i == '-' || i == '.' || i == '_'
             ? i : 0;
+
+    return 0;
 }
     char *
-encode(const char *s)
+xmppipe_encode(const char *s)
 {
     // XXX overflow
     size_t len = strlen(s);

src/xmppipe_id.c

@@ -0,0 +1,30 @@
+/* Copyright (c) 2015, Michael Santos <michael.santos@gmail.com>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+#include "xmppipe.h"
+
+#include <uuid/uuid.h>
+
+    char *
+xmppipe_id_alloc()
+{
+    uuid_t uu = {0};
+    char *out = NULL;
+
+    out = xmppipe_calloc(1,37);
+    uuid_generate(uu);
+    uuid_unparse(uu, out);
+
+    return out;
+}