Allow users to replace allocator and handle OOM everywhere. (#800)

* Adds an indirection to every allocation/deallocation to allow users to 
  plug in ones of their choosing (use custom functions, jemalloc, etc).

* Gracefully handle OOM everywhere in hiredis.  This should make it possible
  for users of the library to have more flexibility in how they handle such situations.

* Changes `redisReaderTask->elements` from an `int` to a `long long` to prevent
  a possible overflow when transferring the task elements into a `redisReply`.

* Adds a configurable `max elements` member to `redisReader` that defaults to
  2^32 - 1.  This can be set to "unlimited" by setting the value to zero.

1 files changed, 4 insertions, 3 deletions

diff --git a/adapters/macosx.h b/adapters/macosx.h
index 72121f6..3c87f1b 100644
--- a/adapters/macosx.h
+++ b/adapters/macosx.h
@@ -27,7 +27,7 @@ static int freeRedisRunLoop(RedisRunLoop* redisRunLoop) {
             CFSocketInvalidate(redisRunLoop->socketRef);
             CFRelease(redisRunLoop->socketRef);
         }
-        free(redisRunLoop);
+        hi_free(redisRunLoop);
     }
     return REDIS_ERR;
 }
@@ -80,8 +80,9 @@ static int redisMacOSAttach(redisAsyncContext *redisAsyncCtx, CFRunLoopRef runLo
     /* Nothing should be attached when something is already attached */
     if( redisAsyncCtx->ev.data != NULL ) return REDIS_ERR;
 
-    RedisRunLoop* redisRunLoop = (RedisRunLoop*) calloc(1, sizeof(RedisRunLoop));
-    if( !redisRunLoop ) return REDIS_ERR;
+    RedisRunLoop* redisRunLoop = (RedisRunLoop*) hi_calloc(1, sizeof(RedisRunLoop));
+    if (redisRunLoop == NULL)
+        return REDIS_ERR;
 
     /* Setup redis stuff */
     redisRunLoop->context = redisAsyncCtx;