lib-mail: message_header_parser_next() updates istream position immed…

…iately now.

Earlier it updated the position only on the next call or at deinit. This was
because some earlier code kept pointers to the stream data and stored them
to the returned struct message_header_line, but we don't do this anymore.

This allows more easily accessing the same istream for other purposes during
the header parsing.

src/lib-mail/message-header-parser.c

@@ -15,7 +15,6 @@ struct message_header_parser_ctx {
 
 	string_t *name;
 	buffer_t *value_buf;
-	size_t skip;
 
 	enum message_header_parser_flags flags;
 	unsigned int skip_line:1;
@@ -44,7 +43,6 @@ void message_parse_header_deinit(struct message_header_parser_ctx **_ctx)
 {
 	struct message_header_parser_ctx *ctx = *_ctx;
 
-	i_stream_skip(ctx->input, ctx->skip);
 	buffer_free(&ctx->value_buf);
 	str_free(&ctx->name);
 	i_free(ctx);
@@ -57,7 +55,7 @@ int message_parse_header_next(struct message_header_parser_ctx *ctx,
 {
         struct message_header_line *line = &ctx->line;
 	const unsigned char *msg;
-	size_t i, size, startpos, colon_pos, parse_size;
+	size_t i, size, startpos, colon_pos, parse_size, skip = 0;
 	int ret;
 	bool continued, continues, last_no_newline, last_crlf;
 	bool no_newline, crlf_newline;
@@ -66,11 +64,6 @@ int message_parse_header_next(struct message_header_parser_ctx *ctx,
 	if (line->eoh)
 		return -1;
 
-	if (ctx->skip > 0) {
-		i_stream_skip(ctx->input, ctx->skip);
-		ctx->skip = 0;
-	}
-
 	if (line->continues)
 		colon_pos = 0;
 	else {
@@ -100,10 +93,11 @@ int message_parse_header_next(struct message_header_parser_ctx *ctx,
 				if (startpos > 0) {
 					/* header ended unexpectedly. */
 					no_newline = TRUE;
-					ctx->skip = startpos;
+					skip = startpos;
 					break;
 				}
 				/* error / EOF with no bytes */
+				i_assert(skip == 0);
 				return -1;
 			}
 
@@ -117,17 +111,18 @@ int message_parse_header_next(struct message_header_parser_ctx *ctx,
 				if (ctx->hdr_size != NULL)
 					ctx->hdr_size->lines++;
 				if (msg[0] == '\r') {
-					ctx->skip = 2;
+					skip = 2;
 					crlf_newline = TRUE;
 				} else {
-					ctx->skip = 1;
+					skip = 1;
 					if (ctx->hdr_size != NULL)
 						ctx->hdr_size->virtual_size++;
 				}
 				break;
 			}
 			if (ret == 0 && !ctx->input->eof) {
 				/* stream is nonblocking - need more data */
+				i_assert(skip == 0);
 				return 0;
 			}
 			i_assert(size > 0);
@@ -161,7 +156,7 @@ int message_parse_header_next(struct message_header_parser_ctx *ctx,
 				continues = TRUE;
 			}
 			no_newline = TRUE;
-			ctx->skip = size;
+			skip = size;
 			break;
 		}
 
@@ -236,7 +231,7 @@ int message_parse_header_next(struct message_header_parser_ctx *ctx,
 				crlf_newline = TRUE;
 			}
 
-			ctx->skip = i+1;
+			skip = i+1;
 			break;
 		}
 
@@ -367,9 +362,10 @@ int message_parse_header_next(struct message_header_parser_ctx *ctx,
 	line->use_full_value = FALSE;
 
 	if (ctx->hdr_size != NULL) {
-		ctx->hdr_size->physical_size += ctx->skip;
-		ctx->hdr_size->virtual_size += ctx->skip;
+		ctx->hdr_size->physical_size += skip;
+		ctx->hdr_size->virtual_size += skip;
 	}
+	i_stream_skip(ctx->input, skip);
 
 	*hdr_r = line;
 	return 1;