allow to pass image filter errors via the same location where the filter is set

src/http/modules/ngx_http_image_filter_module.c

diff --git a/src/http/modules/ngx_http_image_filter_module.c b/src/http/modules/ngx_http_image_filter_module.c
index c68ecb5..83fc145 100644
--- a/src/http/modules/ngx_http_image_filter_module.c
+++ b/src/http/modules/ngx_http_image_filter_module.c
@@ -181,6 +181,13 @@
         return NGX_ERROR;
     }
 
+    ctx = ngx_http_get_module_ctx(r, ngx_http_image_filter_module);
+
+    if (ctx) {
+        ngx_http_set_ctx(r, NULL, ngx_http_image_filter_module);
+        return ngx_http_next_header_filter(r);
+    }
+
     ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_image_filter_ctx_t));
     if (ctx == NULL) {
         return NGX_ERROR;
@@ -258,6 +265,7 @@
             }
 
             return ngx_http_filter_finalize_request(r,
+                                              &ngx_http_image_filter_module,
                                               NGX_HTTP_UNSUPPORTED_MEDIA_TYPE);
         }
 
@@ -287,6 +295,7 @@
 
         if (rc == NGX_ERROR) {
             return ngx_http_filter_finalize_request(r,
+                                              &ngx_http_image_filter_module,
                                               NGX_HTTP_UNSUPPORTED_MEDIA_TYPE);
         }
 
@@ -298,6 +307,7 @@
 
         if (out.buf == NULL) {
             return ngx_http_filter_finalize_request(r,
+                                              &ngx_http_image_filter_module,
                                               NGX_HTTP_UNSUPPORTED_MEDIA_TYPE);
         }
 

src/http/modules/ngx_http_xslt_filter_module.c

diff --git a/src/http/modules/ngx_http_xslt_filter_module.c b/src/http/modules/ngx_http_xslt_filter_module.c
index 4759308..220400c 100644
--- a/src/http/modules/ngx_http_xslt_filter_module.c
+++ b/src/http/modules/ngx_http_xslt_filter_module.c
@@ -319,7 +319,7 @@
     ctx->done = 1;
 
     if (b == NULL) {
-        return ngx_http_filter_finalize_request(r,
+        return ngx_http_filter_finalize_request(r, NULL,
                                                NGX_HTTP_INTERNAL_SERVER_ERROR);
     }
 
@@ -327,7 +327,7 @@
 
     if (cln == NULL) {
         ngx_free(b->pos);
-        return ngx_http_filter_finalize_request(r,
+        return ngx_http_filter_finalize_request(r, NULL,
                                                NGX_HTTP_INTERNAL_SERVER_ERROR);
     }
 

src/http/ngx_http.h

diff --git a/src/http/ngx_http.h b/src/http/ngx_http.h
index 2c442be..9444b11 100644
--- a/src/http/ngx_http.h
+++ b/src/http/ngx_http.h
@@ -104,7 +104,7 @@
 ngx_int_t ngx_http_special_response_handler(ngx_http_request_t *r,
     ngx_int_t error);
 ngx_int_t ngx_http_filter_finalize_request(ngx_http_request_t *r,
-    ngx_int_t error);
+    ngx_module_t *m, ngx_int_t error);
 void ngx_http_clean_header(ngx_http_request_t *r);
 
 

src/http/ngx_http_special_response.c

diff --git a/src/http/ngx_http_special_response.c b/src/http/ngx_http_special_response.c
index 8f0a207..9bf9916 100644
--- a/src/http/ngx_http_special_response.c
+++ b/src/http/ngx_http_special_response.c
@@ -446,15 +446,25 @@
 
 
 ngx_int_t
-ngx_http_filter_finalize_request(ngx_http_request_t *r, ngx_int_t error)
+ngx_http_filter_finalize_request(ngx_http_request_t *r, ngx_module_t *m,
+    ngx_int_t error)
 {
-    ngx_int_t  rc;
+    void       *ctx;
+    ngx_int_t   rc;
 
     ngx_http_clean_header(r);
 
+    if (m) {
+        ctx = r->ctx[m->ctx_index];
+    }
+
     /* clear the modules contexts */
     ngx_memzero(r->ctx, sizeof(void *) * ngx_http_max_module);
 
+    if (m) {
+        r->ctx[m->ctx_index] = ctx;
+    }
+
     r->filter_finalize = 1;
 
     rc = ngx_http_special_response_handler(r, error);