From 3ac8ef927d86df1d7ff1a6546fe590d9bcc0bbd3 Mon Sep 17 00:00:00 2001
From: Pieter Noordhuis <pcnoordhuis@gmail.com>
Date: Fri, 31 Dec 2010 13:46:08 +0100
Subject: [PATCH] Add callbacks to channel/pattern dictionaries

---
 async.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 64 insertions(+), 8 deletions(-)

diff --git a/async.c b/async.c
index dbb70ec..3a5fe2d 100644
--- a/async.c
+++ b/async.c
@@ -31,6 +31,7 @@
 
 #include <string.h>
 #include <assert.h>
+#include <ctype.h>
 #include "async.h"
 #include "sds.h"
 #include "util.h"
@@ -366,23 +367,78 @@ void redisAsyncHandleWrite(redisAsyncContext *ac) {
     }
 }
 
-/* Helper function for the redisAsyncCommand* family of functions.
- *
- * Write a formatted command to the output buffer and register the provided
- * callback function with the context.
- */
+/* Sets a pointer to the first argument and its length starting at p. Returns
+ * the number of bytes to skip to get to the following argument. */
+static char *nextArgument(char *start, char **str, size_t *len) {
+    char *p = start;
+    if (p[0] != '$') {
+        p = strchr(p,'$');
+        if (p == NULL) return NULL;
+    }
+
+    *len = (int)strtol(p+1,NULL,10);
+    p = strchr(p,'\r');
+    assert(p);
+    *str = p+2;
+    return p+2+(*len)+2;
+}
+
+/* Helper function for the redisAsyncCommand* family of functions. Writes a
+ * formatted command to the output buffer and registers the provided callback
+ * function with the context. */
 static int __redisAsyncCommand(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, char *cmd, size_t len) {
     redisContext *c = &(ac->c);
     redisCallback cb;
+    int pvariant, hasnext;
+    char *cstr, *astr;
+    size_t clen, alen;
+    char *p;
+    sds sname;
 
     /* Don't accept new commands when the connection is about to be closed. */
     if (c->flags & (REDIS_DISCONNECTING | REDIS_FREEING)) return REDIS_ERR;
-    __redisAppendCommand(c,cmd,len);
 
-    /* Store callback */
+    /* Setup callback */
     cb.fn = fn;
     cb.privdata = privdata;
-    __redisPushCallback(&ac->replies,&cb);
+
+    /* Find out which command will be appended. */
+    p = nextArgument(cmd,&cstr,&clen);
+    assert(p != NULL);
+    hasnext = (p[0] == '$');
+    pvariant = (tolower(cstr[0]) == 'p') ? 1 : 0;
+    cstr += pvariant;
+    clen -= pvariant;
+
+    if (hasnext && strncasecmp(cstr,"subscribe\r\n",11) == 0) {
+        c->flags |= REDIS_SUBSCRIBED;
+
+        /* Add every channel/pattern to the list of subscription callbacks. */
+        while ((p = nextArgument(p,&astr,&alen)) != NULL) {
+            sname = sdsnewlen(astr,alen);
+            if (pvariant)
+                dictReplace(ac->sub.patterns,sname,&cb);
+            else
+                dictReplace(ac->sub.channels,sname,&cb);
+        }
+    } else if (strncasecmp(cstr,"unsubscribe\r\n",13) == 0) {
+        /* It is only useful to call (P)UNSUBSCRIBE when the context is
+         * subscribed to one or more channels or patterns. */
+        if (!(c->flags & REDIS_SUBSCRIBED)) return REDIS_ERR;
+
+        /* (P)UNSUBSCRIBE does not have its own response: every channel or
+         * pattern that is unsubscribed will receive a message. This means we
+         * should not append a callback function for this command. */
+    } else {
+        if (c->flags & REDIS_SUBSCRIBED)
+            /* This will likely result in an error reply, but it needs to be
+             * received and passed to the callback. */
+            __redisPushCallback(&ac->sub.invalid,&cb);
+        else
+            __redisPushCallback(&ac->replies,&cb);
+    }
+
+    __redisAppendCommand(c,cmd,len);
 
     /* Always schedule a write when the write buffer is non-empty */
     if (ac->ev.addWrite) ac->ev.addWrite(ac->ev.data);