Move prepareClientToWrite out of loop for lrange command to reduce the redundant call.

src/networking.c

@@ -1037,6 +1037,11 @@ void addReplyArrayLen(client *c, long length) {
     addReplyAggregateLen(c, length, '*');
 }
 
+void addReplyArrayLenSkipPrepareClient(client *c, long length) {
+    serverAssert(length >= 0);
+    _addReplyLongLongWithPrefix(c, length, '*');
+}
+
 void addReplyMapLen(client *c, long length) {
     int prefix = c->resp == 2 ? '*' : '%';
     if (c->resp == 2) length *= 2;
@@ -1104,6 +1109,10 @@ void addReplyBulk(client *c, robj *obj) {
 /* Add a C buffer as bulk reply */
 void addReplyBulkCBuffer(client *c, const void *p, size_t len) {
     if (prepareClientToWrite(c) != C_OK) return;
+    addReplyBulkCBufferSkipPrepareClient(c, p, len);
+}
+
+void addReplyBulkCBufferSkipPrepareClient(client *c, const void *p, size_t len) {
     _addReplyLongLongWithPrefix(c, len, '$');
     _addReplyToBufferOrList(c, p, len);
     _addReplyToBufferOrList(c, "\r\n", 2);
@@ -1147,6 +1156,14 @@ void addReplyBulkLongLong(client *c, long long ll) {
     addReplyBulkCBuffer(c, buf, len);
 }
 
+void addReplyBulkLongLongSkipPrepareClient(client *c, long long ll) {
+    char buf[64];
+    int len;
+
+    len = ll2string(buf, 64, ll);
+    addReplyBulkCBufferSkipPrepareClient(c, buf, len);
+}
+
 /* Reply with a verbatim type having the specified extension.
  *
  * The 'ext' is the "extension" of the file, actually just a three

src/server.h

@@ -2774,7 +2774,9 @@ void AddReplyFromClient(client *c, client *src);
 void addReplyBulk(client *c, robj *obj);
 void addReplyBulkCString(client *c, const char *s);
 void addReplyBulkCBuffer(client *c, const void *p, size_t len);
+void addReplyBulkCBufferSkipPrepareClient(client *c, const void *p, size_t len);
 void addReplyBulkLongLong(client *c, long long ll);
+void addReplyBulkLongLongSkipPrepareClient(client *c, long long ll);
 void addReply(client *c, robj *obj);
 void addReplyStatusLength(client *c, const char *s, size_t len);
 void addReplySds(client *c, sds s);
@@ -2796,6 +2798,7 @@ void addReplyBigNum(client *c, const char *num, size_t len);
 void addReplyHumanLongDouble(client *c, long double d);
 void addReplyLongLong(client *c, long long ll);
 void addReplyArrayLen(client *c, long length);
+void addReplyArrayLenSkipPrepareClient(client *c, long length);
 void addReplyMapLen(client *c, long length);
 void addReplySetLen(client *c, long length);
 void addReplyAttributeLen(client *c, long length);

src/t_list.c

@@ -650,6 +650,7 @@ void listPopRangeAndReplyWithKey(client *c, robj *o, robj *key, int where, long
  * Note that the purpose is to make the methods small so that the
  * code in the loop can be inlined better to improve performance. */
 void addListQuicklistRangeReply(client *c, robj *o, int from, int rangelen, int reverse) {
+    if (prepareClientToWrite(c) != C_OK) return;
     /* Return the result in form of a multi-bulk reply */
     addReplyArrayLen(c, rangelen);
 
@@ -659,9 +660,9 @@ void addListQuicklistRangeReply(client *c, robj *o, int from, int rangelen, int
         quicklistEntry qe;
         serverAssert(quicklistNext(iter, &qe)); /* fail on corrupt data */
         if (qe.value) {
-            addReplyBulkCBuffer(c, qe.value, qe.sz);
+            addReplyBulkCBufferSkipPrepareClient(c, qe.value, qe.sz);
         } else {
-            addReplyBulkLongLong(c, qe.longval);
+            addReplyBulkLongLongSkipPrepareClient(c, qe.longval);
         }
     }
     quicklistReleaseIterator(iter);
@@ -671,21 +672,21 @@ void addListQuicklistRangeReply(client *c, robj *o, int from, int rangelen, int
  * Note that the purpose is to make the methods small so that the
  * code in the loop can be inlined better to improve performance. */
 void addListListpackRangeReply(client *c, robj *o, int from, int rangelen, int reverse) {
+    if (prepareClientToWrite(c) != C_OK) return;
+    /* Return the result in form of a multi-bulk reply */
+    addReplyArrayLen(c, rangelen);
     unsigned char *p = lpSeek(o->ptr, from);
     unsigned char *vstr;
     unsigned int vlen;
     long long lval;
 
-    /* Return the result in form of a multi-bulk reply */
-    addReplyArrayLen(c, rangelen);
-
     while (rangelen--) {
         serverAssert(p); /* fail on corrupt data */
         vstr = lpGetValue(p, &vlen, &lval);
         if (vstr) {
-            addReplyBulkCBuffer(c, vstr, vlen);
+            addReplyBulkCBufferSkipPrepareClient(c, vstr, vlen);
         } else {
-            addReplyBulkLongLong(c, lval);
+            addReplyBulkLongLongSkipPrepareClient(c, lval);
         }
         p = reverse ? lpPrev(o->ptr, p) : lpNext(o->ptr, p);
     }