filters can now report an HTTP error to the server. This is done

by sending a brigade where the first bucket is an error_bucket.
This bucket is a simple bucket that stores an HTTP error and
a string.  Currently the string is not used, but it may be needed
to output an error log.  The http_header_filter will find this
bucket, and output the error text, and then return
AP_FILTER_ERROR, which informs the server that the error web page
has already been sent.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@87863 13f79535-47bb-0310-9956-ffa450edef68

2 files changed, 43 insertions, 0 deletions

diff --git a/include/http_protocol.h b/include/http_protocol.h
index 578e03d170..09985a185b 100644
--- a/include/http_protocol.h
+++ b/include/http_protocol.h
@@ -59,9 +59,11 @@
 #ifndef APACHE_HTTP_PROTOCOL_H
 #define APACHE_HTTP_PROTOCOL_H
 
+#include "httpd.h"
 #include "apr_hooks.h"
 #include "apr_portable.h"
 #include "apr_mmap.h"
+#include "apr_buckets.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -550,6 +552,46 @@ AP_DECLARE_HOOK(const char *,http_method,(const request_rec *))
  */
 AP_DECLARE_HOOK(apr_port_t,default_port,(const request_rec *))
 
+typedef struct ap_bucket_error ap_bucket_error;
+/**
+ * A bucket referring to an HTTP error
+ * This bucket can be passed down the filter stack to indicate that an
+ * HTTP error occurred while running a filter.  In order for this bucket
+ * to be used successfully, it MUST be sent as the first bucket in the
+ * first brigade to be sent from a given filter.
+ */
+struct ap_bucket_error {
+    /** The start of the data actually allocated.  This should never be
+     * modified, it is only used to free the bucket.
+     */
+    char    *start;
+};
+
+extern const apr_bucket_type_t ap_bucket_type_error;
+
+/**
+ * Make the bucket passed in an error bucket
+ * @param b The bucket to make into an error bucket
+ * @param error The HTTP error code to put in the bucket. 
+ * @param buf An optional error string to put in the bucket.
+ * @param p A pool to allocate out of.
+ * @return The new bucket, or NULL if allocation failed
+ * @deffunc apr_bucket *ap_bucket_make_error(apr_bucket *b, int error, const char *buf, apr_pool_t *p)
+ */
+AP_DECLARE(apr_bucket *) ap_bucket_make_error(apr_bucket *b, int error,
+                const char *buf, apr_pool_t *p);
+
+/**
+ * Create a bucket referring to an HTTP error.
+ * @param error The HTTP error code to put in the bucket. 
+ * @param buf An optional error string to put in the bucket.
+ * @param p A pool to allocate out of.
+ * @return The new bucket, or NULL if allocation failed
+ * @deffunc apr_bucket *ap_bucket_create_error(int error, const char *buf, apr_pool_t *p)
+ */
+AP_DECLARE(apr_bucket *) ap_bucket_create_error(int error,
+                const char *buf, apr_pool_t *p);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/util_filter.h b/include/util_filter.h
index e01b04a264..e340bd70c9 100644
--- a/include/util_filter.h
+++ b/include/util_filter.h
@@ -73,6 +73,7 @@ extern "C" {
 
 #define AP_NOBODY_WROTE         -1
 #define AP_NOBODY_READ          -2
+#define AP_FILTER_ERROR         -3
 
 /* ap_input_mode_t - input filtering modes 
  *