1 files changed, 1034 insertions, 0 deletions

diff --git a/examples/redis-unstable/deps/hiredis/async.c b/examples/redis-unstable/deps/hiredis/async.c
new file mode 100644
index 0000000..ac56353
--- /dev/null
+++ b/examples/redis-unstable/deps/hiredis/async.c
@@ -0,0 +1,1034 @@
+/*
+ * Copyright (c) 2009-2011, Salvatore Sanfilippo <antirez at gmail dot com>
+ * Copyright (c) 2010-2011, Pieter Noordhuis <pcnoordhuis at gmail dot com>
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *   * Neither the name of Redis nor the names of its contributors may be used
+ *     to endorse or promote products derived from this software without
+ *     specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "fmacros.h"
+#include "alloc.h"
+#include <stdlib.h>
+#include <string.h>
+#ifndef _MSC_VER
+#include <strings.h>
+#endif
+#include <assert.h>
+#include <ctype.h>
+#include <errno.h>
+#include "async.h"
+#include "net.h"
+#include "dict.c"
+#include "sds.h"
+#include "win32.h"
+
+#include "async_private.h"
+
+#ifdef NDEBUG
+#undef assert
+#define assert(e) (void)(e)
+#endif
+
+/* Forward declarations of hiredis.c functions */
+int __redisAppendCommand(redisContext *c, const char *cmd, size_t len);
+void __redisSetError(redisContext *c, int type, const char *str);
+
+/* Functions managing dictionary of callbacks for pub/sub. */
+static unsigned int callbackHash(const void *key) {
+    return dictGenHashFunction((const unsigned char *)key,
+                               hi_sdslen((const hisds)key));
+}
+
+static void *callbackValDup(void *privdata, const void *src) {
+    ((void) privdata);
+    redisCallback *dup;
+
+    dup = hi_malloc(sizeof(*dup));
+    if (dup == NULL)
+        return NULL;
+
+    memcpy(dup,src,sizeof(*dup));
+    return dup;
+}
+
+static int callbackKeyCompare(void *privdata, const void *key1, const void *key2) {
+    int l1, l2;
+    ((void) privdata);
+
+    l1 = hi_sdslen((const hisds)key1);
+    l2 = hi_sdslen((const hisds)key2);
+    if (l1 != l2) return 0;
+    return memcmp(key1,key2,l1) == 0;
+}
+
+static void callbackKeyDestructor(void *privdata, void *key) {
+    ((void) privdata);
+    hi_sdsfree((hisds)key);
+}
+
+static void callbackValDestructor(void *privdata, void *val) {
+    ((void) privdata);
+    hi_free(val);
+}
+
+static dictType callbackDict = {
+    callbackHash,
+    NULL,
+    callbackValDup,
+    callbackKeyCompare,
+    callbackKeyDestructor,
+    callbackValDestructor
+};
+
+static redisAsyncContext *redisAsyncInitialize(redisContext *c) {
+    redisAsyncContext *ac;
+    dict *channels = NULL, *patterns = NULL;
+
+    channels = dictCreate(&callbackDict,NULL);
+    if (channels == NULL)
+        goto oom;
+
+    patterns = dictCreate(&callbackDict,NULL);
+    if (patterns == NULL)
+        goto oom;
+
+    ac = hi_realloc(c,sizeof(redisAsyncContext));
+    if (ac == NULL)
+        goto oom;
+
+    c = &(ac->c);
+
+    /* The regular connect functions will always set the flag REDIS_CONNECTED.
+     * For the async API, we want to wait until the first write event is
+     * received up before setting this flag, so reset it here. */
+    c->flags &= ~REDIS_CONNECTED;
+
+    ac->err = 0;
+    ac->errstr = NULL;
+    ac->data = NULL;
+    ac->dataCleanup = NULL;
+
+    ac->ev.data = NULL;
+    ac->ev.addRead = NULL;
+    ac->ev.delRead = NULL;
+    ac->ev.addWrite = NULL;
+    ac->ev.delWrite = NULL;
+    ac->ev.cleanup = NULL;
+    ac->ev.scheduleTimer = NULL;
+
+    ac->onConnect = NULL;
+    ac->onConnectNC = NULL;
+    ac->onDisconnect = NULL;
+
+    ac->replies.head = NULL;
+    ac->replies.tail = NULL;
+    ac->sub.replies.head = NULL;
+    ac->sub.replies.tail = NULL;
+    ac->sub.channels = channels;
+    ac->sub.patterns = patterns;
+    ac->sub.pending_unsubs = 0;
+
+    return ac;
+oom:
+    if (channels) dictRelease(channels);
+    if (patterns) dictRelease(patterns);
+    return NULL;
+}
+
+/* We want the error field to be accessible directly instead of requiring
+ * an indirection to the redisContext struct. */
+static void __redisAsyncCopyError(redisAsyncContext *ac) {
+    if (!ac)
+        return;
+
+    redisContext *c = &(ac->c);
+    ac->err = c->err;
+    ac->errstr = c->errstr;
+}
+
+redisAsyncContext *redisAsyncConnectWithOptions(const redisOptions *options) {
+    redisOptions myOptions = *options;
+    redisContext *c;
+    redisAsyncContext *ac;
+
+    /* Clear any erroneously set sync callback and flag that we don't want to
+     * use freeReplyObject by default. */
+    myOptions.push_cb = NULL;
+    myOptions.options |= REDIS_OPT_NO_PUSH_AUTOFREE;
+
+    myOptions.options |= REDIS_OPT_NONBLOCK;
+    c = redisConnectWithOptions(&myOptions);
+    if (c == NULL) {
+        return NULL;
+    }
+
+    ac = redisAsyncInitialize(c);
+    if (ac == NULL) {
+        redisFree(c);
+        return NULL;
+    }
+
+    /* Set any configured async push handler */
+    redisAsyncSetPushCallback(ac, myOptions.async_push_cb);
+
+    __redisAsyncCopyError(ac);
+    return ac;
+}
+
+redisAsyncContext *redisAsyncConnect(const char *ip, int port) {
+    redisOptions options = {0};
+    REDIS_OPTIONS_SET_TCP(&options, ip, port);
+    return redisAsyncConnectWithOptions(&options);
+}
+
+redisAsyncContext *redisAsyncConnectBind(const char *ip, int port,
+                                         const char *source_addr) {
+    redisOptions options = {0};
+    REDIS_OPTIONS_SET_TCP(&options, ip, port);
+    options.endpoint.tcp.source_addr = source_addr;
+    return redisAsyncConnectWithOptions(&options);
+}
+
+redisAsyncContext *redisAsyncConnectBindWithReuse(const char *ip, int port,
+                                                  const char *source_addr) {
+    redisOptions options = {0};
+    REDIS_OPTIONS_SET_TCP(&options, ip, port);
+    options.options |= REDIS_OPT_REUSEADDR;
+    options.endpoint.tcp.source_addr = source_addr;
+    return redisAsyncConnectWithOptions(&options);
+}
+
+redisAsyncContext *redisAsyncConnectUnix(const char *path) {
+    redisOptions options = {0};
+    REDIS_OPTIONS_SET_UNIX(&options, path);
+    return redisAsyncConnectWithOptions(&options);
+}
+
+static int
+redisAsyncSetConnectCallbackImpl(redisAsyncContext *ac, redisConnectCallback *fn,
+                                 redisConnectCallbackNC *fn_nc)
+{
+    /* If either are already set, this is an error */
+    if (ac->onConnect || ac->onConnectNC)
+        return REDIS_ERR;
+
+    if (fn) {
+        ac->onConnect = fn;
+    } else if (fn_nc) {
+        ac->onConnectNC = fn_nc;
+    }
+
+    /* The common way to detect an established connection is to wait for
+     * the first write event to be fired. This assumes the related event
+     * library functions are already set. */
+    _EL_ADD_WRITE(ac);
+
+    return REDIS_OK;
+}
+
+int redisAsyncSetConnectCallback(redisAsyncContext *ac, redisConnectCallback *fn) {
+    return redisAsyncSetConnectCallbackImpl(ac, fn, NULL);
+}
+
+int redisAsyncSetConnectCallbackNC(redisAsyncContext *ac, redisConnectCallbackNC *fn) {
+    return redisAsyncSetConnectCallbackImpl(ac, NULL, fn);
+}
+
+int redisAsyncSetDisconnectCallback(redisAsyncContext *ac, redisDisconnectCallback *fn) {
+    if (ac->onDisconnect == NULL) {
+        ac->onDisconnect = fn;
+        return REDIS_OK;
+    }
+    return REDIS_ERR;
+}
+
+/* Helper functions to push/shift callbacks */
+static int __redisPushCallback(redisCallbackList *list, redisCallback *source) {
+    redisCallback *cb;
+
+    /* Copy callback from stack to heap */
+    cb = hi_malloc(sizeof(*cb));
+    if (cb == NULL)
+        return REDIS_ERR_OOM;
+
+    if (source != NULL) {
+        memcpy(cb,source,sizeof(*cb));
+        cb->next = NULL;
+    }
+
+    /* Store callback in list */
+    if (list->head == NULL)
+        list->head = cb;
+    if (list->tail != NULL)
+        list->tail->next = cb;
+    list->tail = cb;
+    return REDIS_OK;
+}
+
+static int __redisShiftCallback(redisCallbackList *list, redisCallback *target) {
+    redisCallback *cb = list->head;
+    if (cb != NULL) {
+        list->head = cb->next;
+        if (cb == list->tail)
+            list->tail = NULL;
+
+        /* Copy callback from heap to stack */
+        if (target != NULL)
+            memcpy(target,cb,sizeof(*cb));
+        hi_free(cb);
+        return REDIS_OK;
+    }
+    return REDIS_ERR;
+}
+
+static void __redisRunCallback(redisAsyncContext *ac, redisCallback *cb, redisReply *reply) {
+    redisContext *c = &(ac->c);
+    if (cb->fn != NULL) {
+        c->flags |= REDIS_IN_CALLBACK;
+        cb->fn(ac,reply,cb->privdata);
+        c->flags &= ~REDIS_IN_CALLBACK;
+    }
+}
+
+static void __redisRunPushCallback(redisAsyncContext *ac, redisReply *reply) {
+    if (ac->push_cb != NULL) {
+        ac->c.flags |= REDIS_IN_CALLBACK;
+        ac->push_cb(ac, reply);
+        ac->c.flags &= ~REDIS_IN_CALLBACK;
+    }
+}
+
+static void __redisRunConnectCallback(redisAsyncContext *ac, int status)
+{
+    if (ac->onConnect == NULL && ac->onConnectNC == NULL)
+        return;
+
+    if (!(ac->c.flags & REDIS_IN_CALLBACK)) {
+        ac->c.flags |= REDIS_IN_CALLBACK;
+        if (ac->onConnect) {
+            ac->onConnect(ac, status);
+        } else {
+            ac->onConnectNC(ac, status);
+        }
+        ac->c.flags &= ~REDIS_IN_CALLBACK;
+    } else {
+        /* already in callback */
+        if (ac->onConnect) {
+            ac->onConnect(ac, status);
+        } else {
+            ac->onConnectNC(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);
+    redisCallback cb;
+    dictIterator it;
+    dictEntry *de;
+
+    /* Execute pending callbacks with NULL reply. */
+    while (__redisShiftCallback(&ac->replies,&cb) == REDIS_OK)
+        __redisRunCallback(ac,&cb,NULL);
+    while (__redisShiftCallback(&ac->sub.replies,&cb) == REDIS_OK)
+        __redisRunCallback(ac,&cb,NULL);
+
+    /* Run subscription callbacks with NULL reply */
+    if (ac->sub.channels) {
+        dictInitIterator(&it,ac->sub.channels);
+        while ((de = dictNext(&it)) != NULL)
+            __redisRunCallback(ac,dictGetEntryVal(de),NULL);
+
+        dictRelease(ac->sub.channels);
+    }
+
+    if (ac->sub.patterns) {
+        dictInitIterator(&it,ac->sub.patterns);
+        while ((de = dictNext(&it)) != NULL)
+            __redisRunCallback(ac,dictGetEntryVal(de),NULL);
+
+        dictRelease(ac->sub.patterns);
+    }
+
+    /* Signal event lib to clean up */
+    _EL_CLEANUP(ac);
+
+    /* Execute disconnect callback. When redisAsyncFree() initiated destroying
+     * this context, the status will always be REDIS_OK. */
+    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) {
+        ac->dataCleanup(ac->data);
+    }
+
+    /* Cleanup self */
+    redisFree(c);
+}
+
+/* Free the async context. When this function is called from a callback,
+ * control needs to be returned to redisProcessCallbacks() before actual
+ * free'ing. To do so, a flag is set on the context which is picked up by
+ * redisProcessCallbacks(). Otherwise, the context is immediately free'd. */
+void redisAsyncFree(redisAsyncContext *ac) {
+    if (ac == NULL)
+        return;
+
+    redisContext *c = &(ac->c);
+
+    c->flags |= REDIS_FREEING;
+    if (!(c->flags & REDIS_IN_CALLBACK))
+        __redisAsyncFree(ac);
+}
+
+/* Helper function to make the disconnect happen and clean up. */
+void __redisAsyncDisconnect(redisAsyncContext *ac) {
+    redisContext *c = &(ac->c);
+
+    /* Make sure error is accessible if there is any */
+    __redisAsyncCopyError(ac);
+
+    if (ac->err == 0) {
+        /* For clean disconnects, there should be no pending callbacks. */
+        int ret = __redisShiftCallback(&ac->replies,NULL);
+        assert(ret == REDIS_ERR);
+    } else {
+        /* Disconnection is caused by an error, make sure that pending
+         * callbacks cannot call new commands. */
+        c->flags |= REDIS_DISCONNECTING;
+    }
+
+    /* cleanup event library on disconnect.
+     * this is safe to call multiple times */
+    _EL_CLEANUP(ac);
+
+    /* For non-clean disconnects, __redisAsyncFree() will execute pending
+     * callbacks with a NULL-reply. */
+    if (!(c->flags & REDIS_NO_AUTO_FREE)) {
+      __redisAsyncFree(ac);
+    }
+}
+
+/* Tries to do a clean disconnect from Redis, meaning it stops new commands
+ * from being issued, but tries to flush the output buffer and execute
+ * callbacks for all remaining replies. When this function is called from a
+ * callback, there might be more replies and we can safely defer disconnecting
+ * to redisProcessCallbacks(). Otherwise, we can only disconnect immediately
+ * when there are no pending callbacks. */
+void redisAsyncDisconnect(redisAsyncContext *ac) {
+    redisContext *c = &(ac->c);
+    c->flags |= REDIS_DISCONNECTING;
+
+    /** unset the auto-free flag here, because disconnect undoes this */
+    c->flags &= ~REDIS_NO_AUTO_FREE;
+    if (!(c->flags & REDIS_IN_CALLBACK) && ac->replies.head == NULL)
+        __redisAsyncDisconnect(ac);
+}
+
+static int __redisGetSubscribeCallback(redisAsyncContext *ac, redisReply *reply, redisCallback *dstcb) {
+    redisContext *c = &(ac->c);
+    dict *callbacks;
+    redisCallback *cb = NULL;
+    dictEntry *de;
+    int pvariant;
+    char *stype;
+    hisds sname = NULL;
+
+    /* Match reply with the expected format of a pushed message.
+     * The type and number of elements (3 to 4) are specified at:
+     * https://redis.io/docs/latest/develop/interact/pubsub/#format-of-pushed-messages */
+    if ((reply->type == REDIS_REPLY_ARRAY && !(c->flags & REDIS_SUPPORTS_PUSH) && reply->elements >= 3) ||
+        reply->type == REDIS_REPLY_PUSH) {
+        assert(reply->element[0]->type == REDIS_REPLY_STRING);
+        stype = reply->element[0]->str;
+        pvariant = (tolower(stype[0]) == 'p') ? 1 : 0;
+
+        if (pvariant)
+            callbacks = ac->sub.patterns;
+        else
+            callbacks = ac->sub.channels;
+
+        /* Locate the right callback */
+        if (reply->element[1]->type == REDIS_REPLY_STRING) {
+            sname = hi_sdsnewlen(reply->element[1]->str,reply->element[1]->len);
+            if (sname == NULL) goto oom;
+
+            if ((de = dictFind(callbacks,sname)) != NULL) {
+                cb = dictGetEntryVal(de);
+                memcpy(dstcb,cb,sizeof(*dstcb));
+            }
+        }
+
+        /* If this is an subscribe reply decrease pending counter. */
+        if (strcasecmp(stype+pvariant,"subscribe") == 0) {
+            assert(cb != NULL);
+            cb->pending_subs -= 1;
+
+        } else if (strcasecmp(stype+pvariant,"unsubscribe") == 0) {
+            if (cb == NULL)
+                ac->sub.pending_unsubs -= 1;
+            else if (cb->pending_subs == 0)
+                dictDelete(callbacks,sname);
+
+            /* If this was the last unsubscribe message, revert to
+             * non-subscribe mode. */
+            assert(reply->element[2]->type == REDIS_REPLY_INTEGER);
+
+            /* Unset subscribed flag only when no pipelined pending subscribe
+             * or pending unsubscribe replies. */
+            if (reply->element[2]->integer == 0
+                && dictSize(ac->sub.channels) == 0
+                && dictSize(ac->sub.patterns) == 0
+                && ac->sub.pending_unsubs == 0) {
+                c->flags &= ~REDIS_SUBSCRIBED;
+
+                /* Move ongoing regular command callbacks. */
+                redisCallback cb;
+                while (__redisShiftCallback(&ac->sub.replies,&cb) == REDIS_OK) {
+                    __redisPushCallback(&ac->replies,&cb);
+                }
+            }
+        }
+        hi_sdsfree(sname);
+    } else {
+        /* Shift callback for pending command in subscribed context. */
+        __redisShiftCallback(&ac->sub.replies,dstcb);
+    }
+    return REDIS_OK;
+oom:
+    __redisSetError(&(ac->c), REDIS_ERR_OOM, "Out of memory");
+    __redisAsyncCopyError(ac);
+    return REDIS_ERR;
+}
+
+#define redisIsSpontaneousPushReply(r) \
+    (redisIsPushReply(r) && !redisIsSubscribeReply(r))
+
+static int redisIsSubscribeReply(redisReply *reply) {
+    char *str;
+    size_t len, off;
+
+    /* We will always have at least one string with the subscribe/message type */
+    if (reply->elements < 1 || reply->element[0]->type != REDIS_REPLY_STRING ||
+        reply->element[0]->len < sizeof("message") - 1)
+    {
+        return 0;
+    }
+
+    /* Get the string/len moving past 'p' if needed */
+    off = tolower(reply->element[0]->str[0]) == 'p';
+    str = reply->element[0]->str + off;
+    len = reply->element[0]->len - off;
+
+    return !strncasecmp(str, "subscribe", len) ||
+           !strncasecmp(str, "message", len) ||
+           !strncasecmp(str, "unsubscribe", len);
+}
+
+void redisProcessCallbacks(redisAsyncContext *ac) {
+    redisContext *c = &(ac->c);
+    void *reply = NULL;
+    int status;
+
+    while((status = redisGetReply(c,&reply)) == REDIS_OK) {
+        if (reply == NULL) {
+            /* When the connection is being disconnected and there are
+             * no more replies, this is the cue to really disconnect. */
+            if (c->flags & REDIS_DISCONNECTING && hi_sdslen(c->obuf) == 0
+                && ac->replies.head == NULL) {
+                __redisAsyncDisconnect(ac);
+                return;
+            }
+            /* When the connection is not being disconnected, simply stop
+             * trying to get replies and wait for the next loop tick. */
+            break;
+        }
+
+        /* Keep track of push message support for subscribe handling */
+        if (redisIsPushReply(reply)) c->flags |= REDIS_SUPPORTS_PUSH;
+
+        /* Send any non-subscribe related PUSH messages to our PUSH handler
+         * while allowing subscribe related PUSH messages to pass through.
+         * This allows existing code to be backward compatible and work in
+         * either RESP2 or RESP3 mode. */
+        if (redisIsSpontaneousPushReply(reply)) {
+            __redisRunPushCallback(ac, reply);
+            c->reader->fn->freeObject(reply);
+            continue;
+        }
+
+        /* Even if the context is subscribed, pending regular
+         * callbacks will get a reply before pub/sub messages arrive. */
+        redisCallback cb = {NULL, NULL, 0, 0, NULL};
+        if (__redisShiftCallback(&ac->replies,&cb) != REDIS_OK) {
+            /*
+             * A spontaneous reply in a not-subscribed context can be the error
+             * reply that is sent when a new connection exceeds the maximum
+             * number of allowed connections on the server side.
+             *
+             * This is seen as an error instead of a regular reply because the
+             * server closes the connection after sending it.
+             *
+             * To prevent the error from being overwritten by an EOF error the
+             * connection is closed here. See issue #43.
+             *
+             * Another possibility is that the server is loading its dataset.
+             * In this case we also want to close the connection, and have the
+             * user wait until the server is ready to take our request.
+             */
+            if (((redisReply*)reply)->type == REDIS_REPLY_ERROR) {
+                c->err = REDIS_ERR_OTHER;
+                snprintf(c->errstr,sizeof(c->errstr),"%s",((redisReply*)reply)->str);
+                c->reader->fn->freeObject(reply);
+                __redisAsyncDisconnect(ac);
+                return;
+            }
+            /* No more regular callbacks and no errors, the context *must* be subscribed. */
+            assert(c->flags & REDIS_SUBSCRIBED);
+            if (c->flags & REDIS_SUBSCRIBED)
+                __redisGetSubscribeCallback(ac,reply,&cb);
+        }
+
+        if (cb.fn != NULL) {
+            __redisRunCallback(ac,&cb,reply);
+            if (!(c->flags & REDIS_NO_AUTO_FREE_REPLIES)){
+                c->reader->fn->freeObject(reply);
+            }
+
+            /* Proceed with free'ing when redisAsyncFree() was called. */
+            if (c->flags & REDIS_FREEING) {
+                __redisAsyncFree(ac);
+                return;
+            }
+        } else {
+            /* No callback for this reply. This can either be a NULL callback,
+             * or there were no callbacks to begin with. Either way, don't
+             * abort with an error, but simply ignore it because the client
+             * doesn't know what the server will spit out over the wire. */
+            c->reader->fn->freeObject(reply);
+        }
+
+        /* If in monitor mode, repush the callback */
+        if (c->flags & REDIS_MONITORING) {
+            __redisPushCallback(&ac->replies,&cb);
+        }
+    }
+
+    /* Disconnect when there was an error reading the reply */
+    if (status != REDIS_OK)
+        __redisAsyncDisconnect(ac);
+}
+
+static void __redisAsyncHandleConnectFailure(redisAsyncContext *ac) {
+    __redisRunConnectCallback(ac, REDIS_ERR);
+    __redisAsyncDisconnect(ac);
+}
+
+/* Internal helper function to detect socket status the first time a read or
+ * write event fires. When connecting was not successful, the connect callback
+ * is called with a REDIS_ERR status and the context is free'd. */
+static int __redisAsyncHandleConnect(redisAsyncContext *ac) {
+    int completed = 0;
+    redisContext *c = &(ac->c);
+
+    if (redisCheckConnectDone(c, &completed) == REDIS_ERR) {
+        /* Error! */
+        if (redisCheckSocketError(c) == REDIS_ERR)
+            __redisAsyncCopyError(ac);
+        __redisAsyncHandleConnectFailure(ac);
+        return REDIS_ERR;
+    } else if (completed == 1) {
+        /* connected! */
+        if (c->connection_type == REDIS_CONN_TCP &&
+            redisSetTcpNoDelay(c) == REDIS_ERR) {
+            __redisAsyncHandleConnectFailure(ac);
+            return REDIS_ERR;
+        }
+
+        /* 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;
+    }
+}
+
+void redisAsyncRead(redisAsyncContext *ac) {
+    redisContext *c = &(ac->c);
+
+    if (redisBufferRead(c) == REDIS_ERR) {
+        __redisAsyncDisconnect(ac);
+    } else {
+        /* Always re-schedule reads */
+        _EL_ADD_READ(ac);
+        redisProcessCallbacks(ac);
+    }
+}
+
+/* This function should be called when the socket is readable.
+ * It processes all replies that can be read and executes their callbacks.
+ */
+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. */
+        if (__redisAsyncHandleConnect(ac) != REDIS_OK)
+            return;
+        /* Try again later when the context is still not connected. */
+        if (!(c->flags & REDIS_CONNECTED))
+            return;
+    }
+
+    c->funcs->async_read(ac);
+}
+
+void redisAsyncWrite(redisAsyncContext *ac) {
+    redisContext *c = &(ac->c);
+    int done = 0;
+
+    if (redisBufferWrite(c,&done) == REDIS_ERR) {
+        __redisAsyncDisconnect(ac);
+    } else {
+        /* Continue writing when not done, stop writing otherwise */
+        if (!done)
+            _EL_ADD_WRITE(ac);
+        else
+            _EL_DEL_WRITE(ac);
+
+        /* Always schedule reads after writes */
+        _EL_ADD_READ(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. */
+        if (__redisAsyncHandleConnect(ac) != REDIS_OK)
+            return;
+        /* Try again later when the context is still not connected. */
+        if (!(c->flags & REDIS_CONNECTED))
+            return;
+    }
+
+    c->funcs->async_write(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) {
+            /* Nothing to do - just an idle timeout */
+            return;
+        }
+
+        if (!ac->c.command_timeout ||
+            (!ac->c.command_timeout->tv_sec && !ac->c.command_timeout->tv_usec)) {
+            /* A belated connect timeout arriving, ignore */
+            return;
+        }
+    }
+
+    if (!c->err) {
+        __redisSetError(c, REDIS_ERR_TIMEOUT, "Timeout");
+        __redisAsyncCopyError(ac);
+    }
+
+    if (!(c->flags & REDIS_CONNECTED)) {
+        __redisRunConnectCallback(ac, REDIS_ERR);
+    }
+
+    while (__redisShiftCallback(&ac->replies, &cb) == REDIS_OK) {
+        __redisRunCallback(ac, &cb, NULL);
+    }
+
+    /**
+     * TODO: Don't automatically sever the connection,
+     * rather, allow to ignore <x> responses before the queue is clear
+     */
+    __redisAsyncDisconnect(ac);
+}
+
+/* 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 const char *nextArgument(const char *start, const char **str, size_t *len) {
+    const 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, const char *cmd, size_t len) {
+    redisContext *c = &(ac->c);
+    redisCallback cb;
+    struct dict *cbdict;
+    dictIterator it;
+    dictEntry *de;
+    redisCallback *existcb;
+    int pvariant, hasnext;
+    const char *cstr, *astr;
+    size_t clen, alen;
+    const char *p;
+    hisds sname;
+    int ret;
+
+    /* Don't accept new commands when the connection is about to be closed. */
+    if (c->flags & (REDIS_DISCONNECTING | REDIS_FREEING)) return REDIS_ERR;
+
+    /* Setup callback */
+    cb.fn = fn;
+    cb.privdata = privdata;
+    cb.pending_subs = 1;
+    cb.unsubscribe_sent = 0;
+
+    /* 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 = hi_sdsnewlen(astr,alen);
+            if (sname == NULL)
+                goto oom;
+
+            if (pvariant)
+                cbdict = ac->sub.patterns;
+            else
+                cbdict = ac->sub.channels;
+
+            de = dictFind(cbdict,sname);
+
+            if (de != NULL) {
+                existcb = dictGetEntryVal(de);
+                cb.pending_subs = existcb->pending_subs + 1;
+            }
+
+            ret = dictReplace(cbdict,sname,&cb);
+
+            if (ret == 0) hi_sdsfree(sname);
+        }
+    } 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;
+
+        if (pvariant)
+            cbdict = ac->sub.patterns;
+        else
+            cbdict = ac->sub.channels;
+
+        if (hasnext) {
+            /* Send an unsubscribe with specific channels/patterns.
+             * Bookkeeping the number of expected replies */
+            while ((p = nextArgument(p,&astr,&alen)) != NULL) {
+                sname = hi_sdsnewlen(astr,alen);
+                if (sname == NULL)
+                    goto oom;
+
+                de = dictFind(cbdict,sname);
+                if (de != NULL) {
+                    existcb = dictGetEntryVal(de);
+                    if (existcb->unsubscribe_sent == 0)
+                        existcb->unsubscribe_sent = 1;
+                    else
+                        /* Already sent, reply to be ignored */
+                        ac->sub.pending_unsubs += 1;
+                } else {
+                    /* Not subscribed to, reply to be ignored */
+                    ac->sub.pending_unsubs += 1;
+                }
+                hi_sdsfree(sname);
+            }
+        } else {
+            /* Send an unsubscribe without specific channels/patterns.
+             * Bookkeeping the number of expected replies */
+            int no_subs = 1;
+            dictInitIterator(&it,cbdict);
+            while ((de = dictNext(&it)) != NULL) {
+                existcb = dictGetEntryVal(de);
+                if (existcb->unsubscribe_sent == 0) {
+                    existcb->unsubscribe_sent = 1;
+                    no_subs = 0;
+                }
+            }
+            /* Unsubscribing to all channels/patterns, where none is
+             * subscribed to, results in a single reply to be ignored. */
+            if (no_subs == 1)
+                ac->sub.pending_unsubs += 1;
+        }
+
+        /* (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 (strncasecmp(cstr,"monitor\r\n",9) == 0) {
+        /* Set monitor flag and push callback */
+        c->flags |= REDIS_MONITORING;
+        if (__redisPushCallback(&ac->replies,&cb) != REDIS_OK)
+            goto oom;
+    } else {
+        if (c->flags & REDIS_SUBSCRIBED) {
+            if (__redisPushCallback(&ac->sub.replies,&cb) != REDIS_OK)
+                goto oom;
+        } else {
+            if (__redisPushCallback(&ac->replies,&cb) != REDIS_OK)
+                goto oom;
+        }
+    }
+
+    __redisAppendCommand(c,cmd,len);
+
+    /* Always schedule a write when the write buffer is non-empty */
+    _EL_ADD_WRITE(ac);
+
+    return REDIS_OK;
+oom:
+    __redisSetError(&(ac->c), REDIS_ERR_OOM, "Out of memory");
+    __redisAsyncCopyError(ac);
+    return REDIS_ERR;
+}
+
+int redisvAsyncCommand(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, const char *format, va_list ap) {
+    char *cmd;
+    int len;
+    int status;
+    len = redisvFormatCommand(&cmd,format,ap);
+
+    /* We don't want to pass -1 or -2 to future functions as a length. */
+    if (len < 0)
+        return REDIS_ERR;
+
+    status = __redisAsyncCommand(ac,fn,privdata,cmd,len);
+    hi_free(cmd);
+    return status;
+}
+
+int redisAsyncCommand(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, const char *format, ...) {
+    va_list ap;
+    int status;
+    va_start(ap,format);
+    status = redisvAsyncCommand(ac,fn,privdata,format,ap);
+    va_end(ap);
+    return status;
+}
+
+int redisAsyncCommandArgv(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, int argc, const char **argv, const size_t *argvlen) {
+    hisds cmd;
+    long long len;
+    int status;
+    len = redisFormatSdsCommandArgv(&cmd,argc,argv,argvlen);
+    if (len < 0)
+        return REDIS_ERR;
+    status = __redisAsyncCommand(ac,fn,privdata,cmd,len);
+    hi_sdsfree(cmd);
+    return status;
+}
+
+int redisAsyncFormattedCommand(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, const char *cmd, size_t len) {
+    int status = __redisAsyncCommand(ac,fn,privdata,cmd,len);
+    return status;
+}
+
+redisAsyncPushFn *redisAsyncSetPushCallback(redisAsyncContext *ac, redisAsyncPushFn *fn) {
+    redisAsyncPushFn *old = ac->push_cb;
+    ac->push_cb = fn;
+    return old;
+}
+
+int redisAsyncSetTimeout(redisAsyncContext *ac, struct timeval tv) {
+    if (!ac->c.command_timeout) {
+        ac->c.command_timeout = hi_calloc(1, sizeof(tv));
+        if (ac->c.command_timeout == NULL) {
+            __redisSetError(&ac->c, REDIS_ERR_OOM, "Out of memory");
+            __redisAsyncCopyError(ac);
+            return REDIS_ERR;
+        }
+    }
+
+    if (tv.tv_sec != ac->c.command_timeout->tv_sec ||
+        tv.tv_usec != ac->c.command_timeout->tv_usec)
+    {
+        *ac->c.command_timeout = tv;
+    }
+
+    return REDIS_OK;
+}