Streams: augment client.bpop with XREAD specific fields.

src/blocked.c

@@ -384,6 +384,10 @@ void unblockClientWaitingData(client *c) {
         decrRefCount(c->bpop.target);
         c->bpop.target = NULL;
     }
+    if (c->bpop.xread_group) {
+        decrRefCount(c->bpop.xread_group);
+        c->bpop.xread_group = NULL;
+    }
 }
 
 /* If the specified key has clients blocked waiting for list pushes, this

src/networking.c

@@ -126,6 +126,7 @@ client *createClient(int fd) {
     c->bpop.timeout = 0;
     c->bpop.keys = dictCreate(&objectKeyHeapPointerValueDictType,NULL);
     c->bpop.target = NULL;
+    c->bpop.xread_group = NULL;
     c->bpop.numreplicas = 0;
     c->bpop.reploffset = 0;
     c->woff = 0;

src/server.h

@@ -648,6 +648,11 @@ typedef struct blockingState {
     robj *target;           /* The key that should receive the element,
                              * for BRPOPLPUSH. */
 
+    /* BLOCK_STREAM */
+    size_t xread_count;     /* XREAD COUNT option. */
+    robj *xread_group;      /* XREAD group name. */
+    mstime_t xread_retry_time, xread_retry_ttl;
+
     /* BLOCKED_WAIT */
     int numreplicas;        /* Number of replicas we are waiting for ACK. */
     long long reploffset;   /* Replication offset to reach. */

src/t_stream.c

@@ -392,3 +392,11 @@ void xlenCommand(client *c) {
     stream *s = o->ptr;
     addReplyLongLong(c,s->length);
 }
+
+/* XREAD [BLOCK <milliseconds>] [COUNT <count>] [GROUP <groupname> <ttl>]
+ *       [RETRY <milliseconds> <ttl>] STREAMS key_1 ID_1 key_2 ID_2 ...
+ *       key_N ID_N */
+void xreadCommand(client *c) {
+}
+
+