From 005d7edebe098bcc90dd0c0003c5710e60d44b63 Mon Sep 17 00:00:00 2001
From: Kristján Valur Jónsson <sweskman@gmail.com>
Date: Tue, 20 Apr 2021 16:16:09 +0000
Subject: Support calling redisAsyncDisconnect from the onConnected callback,
 by deferring context deletion

---
 async.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 54 insertions(+), 10 deletions(-)

diff --git a/async.c b/async.c
index 3dad137..73b7980 100644
--- a/async.c
+++ b/async.c
@@ -303,6 +303,34 @@ static void __redisRunPushCallback(redisAsyncContext *ac, redisReply *reply) {
     }
 }
 
+static void __redisRunConnectCallback(redisAsyncContext *ac, int status)
+{
+    if (ac->onConnect) {
+        if (!(ac->c.flags & REDIS_IN_CALLBACK)) {
+            ac->c.flags |= REDIS_IN_CALLBACK;
+            ac->onConnect(ac, status);
+            ac->c.flags &= ~REDIS_IN_CALLBACK;
+        } else {
+            /* already in callback */
+            ac->onConnect(ac, status);
+        }
+    }
+}
+
+static void __redisRunDisconnectCallback(redisAsyncContext *ac, int status)
+{
+    if (ac->onDisconnect) {
+        if (!(ac->c.flags & REDIS_IN_CALLBACK)) {
+            ac->c.flags |= REDIS_IN_CALLBACK;
+            ac->onDisconnect(ac, status);
+            ac->c.flags &= ~REDIS_IN_CALLBACK;
+        } else {
+            /* already in callback */
+            ac->onDisconnect(ac, status);
+        }
+    }
+}
+
 /* Helper function to free the context. */
 static void __redisAsyncFree(redisAsyncContext *ac) {
     redisContext *c = &(ac->c);
@@ -338,12 +366,11 @@ static void __redisAsyncFree(redisAsyncContext *ac) {
 
     /* Execute disconnect callback. When redisAsyncFree() initiated destroying
      * this context, the status will always be REDIS_OK. */
-    if (ac->onDisconnect && (c->flags & REDIS_CONNECTED)) {
-        if (c->flags & REDIS_FREEING) {
-            ac->onDisconnect(ac,REDIS_OK);
-        } else {
-            ac->onDisconnect(ac,(ac->err == 0) ? REDIS_OK : REDIS_ERR);
-        }
+    if (c->flags & REDIS_CONNECTED) {
+        int status = ac->err == 0 ? REDIS_OK : REDIS_ERR;
+        if (c->flags & REDIS_FREEING)
+            status = REDIS_OK;
+        __redisRunDisconnectCallback(ac, status);
     }
 
     if (ac->dataCleanup) {
@@ -603,7 +630,7 @@ void redisProcessCallbacks(redisAsyncContext *ac) {
 }
 
 static void __redisAsyncHandleConnectFailure(redisAsyncContext *ac) {
-    if (ac->onConnect) ac->onConnect(ac, REDIS_ERR);
+    __redisRunConnectCallback(ac, REDIS_ERR);
     __redisAsyncDisconnect(ac);
 }
 
@@ -628,8 +655,19 @@ static int __redisAsyncHandleConnect(redisAsyncContext *ac) {
             return REDIS_ERR;
         }
 
-        if (ac->onConnect) ac->onConnect(ac, REDIS_OK);
+        /* flag us as fully connect, but allow the callback
+         * to disconnect.  For that reason, permit the function
+         * to delete the context here after callback return.
+         */
         c->flags |= REDIS_CONNECTED;
+        __redisRunConnectCallback(ac, REDIS_OK);
+        if ((ac->c.flags & REDIS_DISCONNECTING)) {
+            redisAsyncDisconnect(ac);
+            return REDIS_ERR;
+        } else if ((ac->c.flags & REDIS_FREEING)) {
+            redisAsyncFree(ac);
+            return REDIS_ERR;
+        }
         return REDIS_OK;
     } else {
         return REDIS_OK;
@@ -653,6 +691,8 @@ void redisAsyncRead(redisAsyncContext *ac) {
  */
 void redisAsyncHandleRead(redisAsyncContext *ac) {
     redisContext *c = &(ac->c);
+    /* must not be called from a callback */
+    assert(!(c->flags & REDIS_IN_CALLBACK));
 
     if (!(c->flags & REDIS_CONNECTED)) {
         /* Abort connect was not successful. */
@@ -686,6 +726,8 @@ void redisAsyncWrite(redisAsyncContext *ac) {
 
 void redisAsyncHandleWrite(redisAsyncContext *ac) {
     redisContext *c = &(ac->c);
+    /* must not be called from a callback */
+    assert(!(c->flags & REDIS_IN_CALLBACK));
 
     if (!(c->flags & REDIS_CONNECTED)) {
         /* Abort connect was not successful. */
@@ -702,6 +744,8 @@ void redisAsyncHandleWrite(redisAsyncContext *ac) {
 void redisAsyncHandleTimeout(redisAsyncContext *ac) {
     redisContext *c = &(ac->c);
     redisCallback cb;
+    /* must not be called from a callback */
+    assert(!(c->flags & REDIS_IN_CALLBACK));
 
     if ((c->flags & REDIS_CONNECTED)) {
         if (ac->replies.head == NULL && ac->sub.replies.head == NULL) {
@@ -721,8 +765,8 @@ void redisAsyncHandleTimeout(redisAsyncContext *ac) {
         __redisAsyncCopyError(ac);
     }
 
-    if (!(c->flags & REDIS_CONNECTED) && ac->onConnect) {
-        ac->onConnect(ac, REDIS_ERR);
+    if (!(c->flags & REDIS_CONNECTED)) {
+        __redisRunConnectCallback(ac, REDIS_ERR);
     }
 
     while (__redisShiftCallback(&ac->replies, &cb) == REDIS_OK) {
-- 
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