Return NGHTTP2_ERR_BUFFER_ERROR from nghttp2_hd_{deflate,inflate}_hd

It is generally useful to know what is the cause of the error.  Since
we expose HPACK API, it is friendly to tell application the
insufficient buffer size is a culprit.

lib/includes/nghttp2/nghttp2.h

@@ -200,6 +200,10 @@ typedef enum {
    * Invalid argument passed.
    */
   NGHTTP2_ERR_INVALID_ARGUMENT = -501,
+  /**
+   * Ouf of buffer space.
+   */
+  NGHTTP2_ERR_BUFFER_ERROR = -502,
   /**
    * The specified protocol version is not supported.
    */
@@ -2811,6 +2815,8 @@ typedef enum {
  *     Out of memory.
  * :enum:`NGHTTP2_ERR_HEADER_COMP`
  *     Inflation process has failed.
+ * :enum:`NGHTTP2_ERR_BUFFER_ERROR`
+ *     The heder field name or value is too large.
  *
  * Example follows::
  *

lib/nghttp2_frame.c

@@ -366,6 +366,10 @@ int nghttp2_frame_pack_headers(nghttp2_bufs *bufs,
   /* This call will adjust buf->last to the correct position */
   rv = nghttp2_hd_deflate_hd(deflater, bufs, frame->nva, frame->nvlen);
 
+  if(rv == NGHTTP2_ERR_BUFFER_ERROR) {
+    rv = NGHTTP2_ERR_HEADER_COMP;
+  }
+
   buf->pos -= nv_offset;
 
   if(rv != 0) {
@@ -593,6 +597,10 @@ int nghttp2_frame_pack_push_promise(nghttp2_bufs *bufs,
   /* This call will adjust buf->last to the correct position */
   rv = nghttp2_hd_deflate_hd(deflater, bufs, frame->nva, frame->nvlen);
 
+  if(rv == NGHTTP2_ERR_BUFFER_ERROR) {
+    rv = NGHTTP2_ERR_HEADER_COMP;
+  }
+
   buf->pos -= nv_offset;
 
   if(rv != 0) {

lib/nghttp2_hd.c

@@ -559,14 +559,6 @@ static  uint8_t* decode_length(ssize_t *res, int *final, ssize_t initial,
   return in + 1;
 }
 
-static int hd_handle_buffer_error(int rv)
-{
-  if(rv == NGHTTP2_ERR_BUFFER_ERROR) {
-    return NGHTTP2_ERR_HEADER_COMP;
-  }
-  return rv;
-}
-
 static int emit_clear_refset(nghttp2_bufs *bufs)
 {
   int rv;
@@ -575,7 +567,7 @@ static int emit_clear_refset(nghttp2_bufs *bufs)
 
   rv = nghttp2_bufs_addb(bufs, 0x30u);
   if(rv != 0) {
-    return hd_handle_buffer_error(rv);
+    return rv;
   }
 
   return 0;
@@ -604,7 +596,7 @@ static int emit_table_size(nghttp2_bufs *bufs, size_t table_size)
 
   rv = nghttp2_bufs_add(bufs, sb, blocklen);
   if(rv != 0) {
-    return hd_handle_buffer_error(rv);
+    return rv;
   }
 
   return 0;
@@ -632,7 +624,7 @@ static int emit_indexed_block(nghttp2_bufs *bufs, size_t index)
 
   rv = nghttp2_bufs_add(bufs, sb, blocklen);
   if(rv != 0) {
-    return hd_handle_buffer_error(rv);
+    return rv;
   }
 
   return 0;
@@ -665,7 +657,7 @@ static int emit_string(nghttp2_bufs *bufs,
 
   rv = nghttp2_bufs_add(bufs, sb, blocklen);
   if(rv != 0) {
-    return hd_handle_buffer_error(rv);
+    return rv;
   }
 
   if(huffman) {
@@ -675,7 +667,7 @@ static int emit_string(nghttp2_bufs *bufs,
     rv = nghttp2_bufs_add(bufs, str, len);
   }
 
-  return hd_handle_buffer_error(rv);
+  return rv;
 }
 
 static uint8_t pack_first_byte(int inc_indexing, int no_index)
@@ -737,7 +729,7 @@ static int emit_indname_block(nghttp2_bufs *bufs, size_t index,
 
   rv = nghttp2_bufs_add(bufs, sb, blocklen);
   if(rv != 0) {
-    return hd_handle_buffer_error(rv);
+    return rv;
   }
 
   rv = emit_string(bufs, encvallen, huffman, nv->value, nv->valuelen);
@@ -779,7 +771,7 @@ static int emit_newname_block(nghttp2_bufs *bufs, nghttp2_nv *nv,
 
   rv = nghttp2_bufs_addb(bufs, pack_first_byte(inc_indexing, no_index));
   if(rv != 0) {
-    return hd_handle_buffer_error(rv);
+    return rv;
   }
 
   rv = emit_string(bufs, encnamelen, name_huffman, nv->name, nv->namelen);
@@ -1319,6 +1311,8 @@ static ssize_t hd_inflate_read_len(nghttp2_hd_inflater *inflater,
  *   Out of memory
  * NGHTTP2_ERR_HEADER_COMP
  *   Huffman decoding failed
+ * NGHTTP2_ERR_BUFFER_ERROR
+ *     Out of buffer space.
  */
 static ssize_t hd_inflate_read_huff(nghttp2_hd_inflater *inflater,
                                     nghttp2_bufs *bufs,
@@ -1332,9 +1326,7 @@ static ssize_t hd_inflate_read_huff(nghttp2_hd_inflater *inflater,
   }
   rv = nghttp2_hd_huff_decode(&inflater->huff_decode_ctx, bufs,
                               in, last - in, final);
-  if(rv == NGHTTP2_ERR_BUFFER_ERROR) {
-    return NGHTTP2_ERR_HEADER_COMP;
-  }
+
   if(rv < 0) {
     DEBUGF(fprintf(stderr, "inflatehd: huffman decoding failed\n"));
     return rv;
@@ -1354,6 +1346,8 @@ static ssize_t hd_inflate_read_huff(nghttp2_hd_inflater *inflater,
  *   Out of memory
  * NGHTTP2_ERR_HEADER_COMP
  *   Header decompression failed
+ * NGHTTP2_ERR_BUFFER_ERROR
+ *     Out of buffer space.
  */
 static ssize_t hd_inflate_read(nghttp2_hd_inflater *inflater,
                                nghttp2_bufs *bufs,
@@ -1362,9 +1356,6 @@ static ssize_t hd_inflate_read(nghttp2_hd_inflater *inflater,
   int rv;
   size_t len = nghttp2_min(last - in, inflater->left);
   rv = nghttp2_bufs_add(bufs, in, len);
-  if(rv == NGHTTP2_ERR_BUFFER_ERROR) {
-    return NGHTTP2_ERR_HEADER_COMP;
-  }
   if(rv != 0) {
     return rv;
   }

lib/nghttp2_hd.h

@@ -286,6 +286,8 @@ int nghttp2_hd_deflate_change_table_size(nghttp2_hd_deflater *deflater,
  *     Out of memory.
  * NGHTTP2_ERR_HEADER_COMP
  *     Deflation process has failed.
+ * NGHTTP2_ERR_BUFFER_ERROR
+ *     Out of buffer space.
  */
 int nghttp2_hd_deflate_hd(nghttp2_hd_deflater *deflater,
                           nghttp2_bufs *bufs,

lib/nghttp2_helper.c

@@ -167,6 +167,8 @@ const char* nghttp2_strerror(int error_code)
     return "Success";
   case NGHTTP2_ERR_INVALID_ARGUMENT:
     return "Invalid argument";
+  case NGHTTP2_ERR_BUFFER_ERROR:
+    return "Out of buffer space";
   case NGHTTP2_ERR_UNSUPPORTED_VERSION:
     return "Unsupported SPDY version";
   case NGHTTP2_ERR_WOULDBLOCK:

lib/nghttp2_int.h

@@ -45,7 +45,6 @@ typedef int (*nghttp2_compar)(const void *lhs, const void *rhs);
    inclusive. */
 typedef enum {
   NGHTTP2_ERR_CREDENTIAL_PENDING = -101,
-  NGHTTP2_ERR_BUFFER_ERROR = -102,
   NGHTTP2_ERR_IGN_HEADER_BLOCK = -103,
   NGHTTP2_ERR_IGN_PAYLOAD = -104
 } nghttp2_internal_error;