From d1e95674256636c6810012aa1772eb1440579dd5 Mon Sep 17 00:00:00 2001
From: Igor Sysoev <igor@sysoev.ru>
Date: Tue, 15 Sep 2009 15:12:03 +0000
Subject: [PATCH] do not pass buf with empty cached response, this fixes "zero
 size buf in output" alert

---
 src/http/ngx_http_file_cache.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/http/ngx_http_file_cache.c b/src/http/ngx_http_file_cache.c
index a6271a8e9..ca333fc14 100644
--- a/src/http/ngx_http_file_cache.c
+++ b/src/http/ngx_http_file_cache.c
@@ -767,6 +767,7 @@ ngx_http_file_cache_update(ngx_http_request_t *r, ngx_temp_file_t *tf)
 ngx_int_t
 ngx_http_cache_send(ngx_http_request_t *r)
 {
+    off_t              size;
     ngx_int_t          rc;
     ngx_buf_t         *b;
     ngx_chain_t        out;
@@ -795,10 +796,15 @@ ngx_http_cache_send(ngx_http_request_t *r)
         return rc;
     }
 
+    size = c->length - c->body_start;
+    if (size == 0) {
+        return rc;
+    }
+
     b->file_pos = c->body_start;
     b->file_last = c->length;
 
-    b->in_file = (c->length - c->body_start) ? 1: 0;
+    b->in_file = size ? 1: 0;
     b->last_buf = (r == r->main) ? 1: 0;
     b->last_in_chain = 1;