code review: fixed several review comments.

lib/ngx/resolver.lua

@@ -2,7 +2,6 @@ local base = require "resty.core.base"
 local get_request = base.get_request
 local ffi = require "ffi"
 local C = ffi.C
-local ffi_new = ffi.new
 local ffi_str = ffi.string
 local ffi_gc = ffi.gc
 local FFI_OK = base.FFI_OK
@@ -33,7 +32,8 @@ typedef struct {
     unsigned                         ipv6:1;
 } ngx_http_lua_resolver_ctx_t;
 
-int ngx_http_lua_ffi_resolve(ngx_http_lua_resolver_ctx_t *ctx, const char *hostname);
+int ngx_http_lua_ffi_resolve(ngx_http_lua_resolver_ctx_t *ctx,
+    const char *hostname);
 
 void ngx_http_lua_ffi_resolver_destroy(ngx_http_lua_resolver_ctx_t *ctx);
 ]]
@@ -47,18 +47,22 @@ local mt = {
 local Ctx = ffi.metatype("ngx_http_lua_resolver_ctx_t", mt)
 
 function _M.resolve(hostname, ipv4, ipv6)
-    assert(type(hostname) == "string", "hostname must be string")
-    assert(ipv4 == nil or type(ipv4) == "boolean", "ipv4 must be boolean or nil")
-    assert(ipv6 == nil or type(ipv6) == "boolean", "ipv6 must be boolean or nil")
-
     local buf = get_string_buf(BUF_SIZE)
     local buf_size = get_size_ptr()
     buf_size[0] = BUF_SIZE
 
-    local ctx = Ctx({get_request(), buf, buf_size})
+    local ctx = Ctx()
+    ctx.request = get_request()
+    ctx.buf = buf
+    ctx.buf_size = buf_size
+
+    if ipv4 == nil or ipv4 then
+        ctx.ipv4 = 1
+    end
 
-    ctx.ipv4 = ipv4 == nil and 1 or ipv4
-    ctx.ipv6 = ipv6 == nil and 0 or ipv6
+    if ipv6 then
+        ctx.ipv6 = 1
+    end
 
     local rc = C.ngx_http_lua_ffi_resolve(ctx, hostname)