Direct exchange

Makefile

@@ -1,5 +1,6 @@
 TARGET = cmsg
-OBJECTS = main.o harness.o net.o util.o relay.o hashtable.o dataq.o sexp.o sexpio.o node.o queue.o
+OBJECTS = main.o harness.o net.o util.o relay.o hashtable.o dataq.o sexp.o sexpio.o node.o \
+	queue.o direct.o
 
 UUID_CFLAGS:=$(shell uuid-config --cflags)
 UUID_LDFLAGS:=$(shell uuid-config --ldflags)

direct.c

@@ -0,0 +1,184 @@
+/* Copyright (C) 2010 Tony Garnock-Jones. All rights reserved. */
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <stdint.h>
+#include <stddef.h>
+
+#include <assert.h>
+
+#include <ucontext.h>
+
+#include "cmsg_private.h"
+#include "harness.h"
+#include "ref.h"
+#include "sexp.h"
+#include "hashtable.h"
+#include "node.h"
+
+typedef struct direct_extension_t_ {
+  sexp_t *name;
+  hashtable_t routing_table;
+  hashtable_t subscriptions;
+} direct_extension_t;
+
+typedef struct subscription_t_ {
+  sexp_t *uuid;
+  sexp_t *sink;
+  sexp_t *name;
+  struct subscription_t_ *link;
+} subscription_t;
+
+static void free_subscription(subscription_t *sub) {
+  DECREF(sub->uuid, sexp_destructor);
+  DECREF(sub->sink, sexp_destructor);
+  DECREF(sub->name, sexp_destructor);
+  free(sub);
+}
+
+static void free_subscription_chain(void *context, cmsg_bytes_t key, void *value) {
+  subscription_t *chain = value;
+  while (chain != NULL) {
+    subscription_t *next = chain->link;
+    free_subscription(chain);
+    chain = next;
+  }
+}
+
+static sexp_t *direct_extend(node_t *n, sexp_t *args) {
+  if ((sexp_length(args) == 1) && sexp_stringp(sexp_head(args))) {
+    cmsg_bytes_t name = sexp_data(sexp_head(args));
+    direct_extension_t *d = calloc(1, sizeof(*d));
+    d->name = INCREF(sexp_head(args));
+    init_hashtable(&d->routing_table, 5, NULL, NULL);
+    init_hashtable(&d->subscriptions, 5, NULL, NULL);
+
+    n->extension = d;
+    return bind_node(name, n) ? NULL : sexp_cstring("bind failed");
+  } else {
+    return sexp_cstring("invalid args");
+  }
+}
+
+static void direct_destructor(node_t *n) {
+  direct_extension_t *d = n->extension;
+  if (d != NULL) { /* can be NULL if direct_extend was given invalid args */
+    DECREF(d->name, sexp_destructor);
+    hashtable_foreach(&d->routing_table, free_subscription_chain, NULL);
+    destroy_hashtable(&d->routing_table);
+    destroy_hashtable(&d->subscriptions);
+    free(d);
+  }
+}
+
+static int send_to_sub(subscription_t *sub, sexp_t *body) {
+  return post_node(sexp_data(sub->sink), sexp_data(sub->name), body, sub->uuid);
+}
+
+static void route_message(direct_extension_t *d, sexp_t *rk, sexp_t *body) {
+  subscription_t *chain = NULL;
+  subscription_t *prev = NULL;
+  hashtable_get(&d->routing_table, sexp_data(rk), (void **) &chain);
+  while (chain != NULL) {
+    subscription_t *next = chain->link;
+    if (!send_to_sub(chain, body)) { /* Destination no longer exists. */
+      info("Destination not found\n");
+      if (prev == NULL) {
+	hashtable_put(&d->routing_table, sexp_data(rk), chain->link);
+      } else {
+	prev->link = chain->link;
+      }
+      chain->link = NULL;
+      free_subscription(chain);
+    }
+    chain = next;
+  }
+}
+
+static void direct_handle_message(node_t *n, sexp_t *m) {
+  direct_extension_t *d = n->extension;
+
+  size_t msglen = sexp_length(m);
+  sexp_t *args;
+  cmsg_bytes_t selector;
+
+  if (msglen == 0 || !sexp_stringp(sexp_head(m))) {
+    warn("Invalid message in direct\n");
+    return;
+  }
+
+  selector = sexp_data(sexp_head(m));
+  args = sexp_tail(m);
+
+  if ((msglen == 4) && !cmsg_bytes_cmp(selector, cmsg_cstring_bytes("post"))) {
+    sexp_t *rk = sexp_listref(args, 0);
+    if (sexp_stringp(rk)) {
+      route_message(d, rk, sexp_listref(args, 1));
+    } else {
+      warn("Non-string routing key in direct\n");
+    }
+  } else if ((msglen == 6) && !cmsg_bytes_cmp(selector, cmsg_cstring_bytes("subscribe"))) {
+    unsigned char uuid[CMSG_UUID_BUF_SIZE];
+    if (gen_uuid(uuid) != 0) {
+      warn("Could not generate UUID\n");
+    } else {
+      sexp_t *filter = sexp_listref(args, 0);
+      sexp_t *reply_sink = sexp_listref(args, 3);
+      sexp_t *reply_name = sexp_listref(args, 4);
+      subscription_t *sub = malloc(sizeof(*sub));
+      sub->uuid = INCREF(sexp_bytes(CMSG_BYTES(sizeof(uuid), uuid)));
+      sub->sink = sexp_listref(args, 1);
+      sub->name = sexp_listref(args, 2);
+      sub->link = NULL;
+      if (!sexp_stringp(filter)
+	  || !sexp_stringp(sub->sink) || !sexp_stringp(sub->name)
+	  || !sexp_stringp(reply_sink) || !sexp_stringp(reply_name)) {
+	DECREF(sub->uuid, sexp_destructor);
+	free(sub);
+	warn("Bad sink/name/reply_sink/reply_name in subscribe");
+      } else {
+	INCREF(sub->sink);
+	INCREF(sub->name);
+	hashtable_put(&d->subscriptions, sexp_data(sub->uuid), sub);
+	hashtable_get(&d->routing_table, sexp_data(filter), (void **) &sub->link);
+	hashtable_put(&d->routing_table, sexp_data(filter), sub);
+	{
+	  sexp_t *subok = sexp_cons(sexp_cstring("subscribe-ok"), sexp_cons(sub->uuid, NULL));
+	  INCREF(subok);
+	  post_node(sexp_data(reply_sink), sexp_data(reply_name), subok, sexp_empty_bytes);
+	  DECREF(subok, sexp_destructor);
+	}
+      }
+    }
+  } else if ((msglen == 2) && !cmsg_bytes_cmp(selector, cmsg_cstring_bytes("unsubscribe"))) {
+    if (sexp_stringp(sexp_head(args))) {
+      cmsg_bytes_t uuid = sexp_data(sexp_head(args));
+      subscription_t *sub;
+      if (hashtable_get(&d->subscriptions, uuid, (void **) &sub)) {
+	/* TODO: clean up more eagerly perhaps? */
+	hashtable_erase(&d->subscriptions, uuid);
+	DECREF(sub->uuid, sexp_destructor);
+	sub->uuid = NULL;
+      }
+    } else {
+      warn("Invalid unsubscription\n");
+    }
+  } else {
+    warn("Message not understood in direct; selector <<%.*s>>, length %u\n",
+	 selector.len, selector.bytes,
+	 msglen);
+  }
+}
+
+static node_class_t direct_class = {
+  .name = "direct",
+  .extend = direct_extend,
+  .destroy = direct_destructor,
+  .handle_message = direct_handle_message
+};
+
+void init_direct(void) {
+  register_node_class(&direct_class);
+}

direct.h

@@ -0,0 +1,6 @@
+#ifndef cmsg_direct_h
+#define cmsg_direct_h
+
+extern void init_direct(void);
+
+#endif

main.c

@@ -21,6 +21,7 @@ typedef unsigned char u_char;
 #include "hashtable.h"
 #include "node.h"
 #include "queue.h"
+#include "direct.h"
 
 #define WANT_CONSOLE_LISTENER 1
 
@@ -101,6 +102,7 @@ int main(int argc, char *argv[]) {
   init_node();
   init_factory();
   init_queue();
+  init_direct();
 #if WANT_CONSOLE_LISTENER
   spawn(console_listener, NULL);
 #endif

queue.c

@@ -179,7 +179,7 @@ static void queue_handle_message(node_t *n, sexp_t *m) {
   cmsg_bytes_t selector;
 
   if (msglen == 0 || !sexp_stringp(sexp_head(m))) {
-    warn("Invalid message in factory\n");
+    warn("Invalid message in queue\n");
     return;
   }
 
@@ -204,6 +204,7 @@ static void queue_handle_message(node_t *n, sexp_t *m) {
       if (!sexp_stringp(sub->sink) || !sexp_stringp(sub->name)
 	  || !sexp_stringp(reply_sink) || !sexp_stringp(reply_name)) {
 	DECREF(sub->uuid, sexp_destructor);
+	free(sub);
 	warn("Bad sink/name/reply_sink/reply_name in subscribe");
       } else {
 	INCREF(sub->sink);

sexp.c

@@ -48,6 +48,14 @@ static inline void release_shell(sexp_t *x) {
   freelist = x;
 }
 
+sexp_t *sexp_incref(sexp_t *x) {
+  return INCREF(x);
+}
+
+sexp_t *sexp_decref(sexp_t *x) {
+  return DECREF(x, sexp_destructor);
+}
+
 void sexp_data_destructor(sexp_data_t *data) {
   cmsg_bytes_free(data->data);
   free(data);

sexp.h

@@ -35,6 +35,9 @@ extern sexp_t *sexp_empty_bytes;
 extern void init_sexp(void);
 extern void done_sexp(void);
 
+extern sexp_t *sexp_incref(sexp_t *x);
+extern sexp_t *sexp_decref(sexp_t *x);
+
 extern void sexp_data_destructor(sexp_data_t *data);
 extern void sexp_destructor(sexp_t *x);
 

t4

@@ -0,0 +1,4 @@
+(9:subscribe5:test40:0:5:test45:login)
+(4:post7:factory(6:create6:direct(2:dx)5:test41:k)0:)
+(4:post2:dx(9:subscribe1:a5:test48:consumer5:test41:k)0:)
+(4:post2:dx(9:subscribe1:c5:test48:consumer5:test41:k)0:)

t5

@@ -0,0 +1,7 @@
+(9:subscribe5:test50:0:5:test55:login)
+(4:post7:factory(6:create6:direct(2:dx)5:test51:k)0:)
+(4:post7:factory(6:create5:queue(2:q5)5:test51:k)0:)
+(4:post2:q5(9:subscribe0:5:test59:consumer15:test51:k)0:)
+(4:post2:q5(9:subscribe0:5:test59:consumer25:test51:k)0:)
+(4:post2:dx(9:subscribe1:a2:q50:5:test51:k)0:)
+(4:post2:dx(9:subscribe1:b2:q50:5:test51:k)0:)

t6

@@ -0,0 +1,6 @@
+(9:subscribe5:test60:0:5:test65:login)
+(4:post2:dx(4:post1:a9:messageA10:)0:)
+(4:post2:dx(4:post1:a9:messageA20:)0:)
+(4:post2:dx(4:post1:b8:messageB0:)0:)
+(4:post2:dx(4:post1:c8:messageC0:)0:)
+(11:unsubscribe5:test6)