xz: Fix suffix check.

The suffix refactor done in 99575947a58a60416c570eb78038d18a1ea4cef4
had a small regression where raw format compression to standard out
failed if a suffix was not set. In this case, setting the suffix did
not make sense since a file is not created.

Now, xz should only fail when a suffix is not provided when it is
actually needed.

For instance:

    echo "foo" | xz --format=raw --lzma2 | wc -c

does not need a suffix check since it creates no files. But:

    xz --format=raw --lzma2 --suffix=.bar foo

Needs the suffix to be set since it must create foo.bar.

1 files changed, 22 insertions, 8 deletions

diff --git a/src/xz/args.c b/src/xz/args.c
index 17e778c5..a94e0d9e 100644
--- a/src/xz/args.c
+++ b/src/xz/args.c
@@ -718,6 +718,28 @@ args_parse(args_info *args, int argc, char **argv)
 	if (opt_mode == MODE_COMPRESS && opt_format == FORMAT_AUTO)
 		opt_format = FORMAT_XZ;
 
+	// If raw format is used and a custom suffix is not provided,
+	// then only stdout mode can be used when compressing or
+	// decompressing.
+	if (opt_format == FORMAT_RAW && !suffix_is_set() && !opt_stdout
+			&& (opt_mode == MODE_COMPRESS
+				|| opt_mode == MODE_DECOMPRESS)) {
+		if (args->files_name != NULL)
+			message_fatal(_("With --format=raw, "
+					"--suffix=.SUF is required "
+					"unless writing to stdout"));
+
+		// If all of the filenames provided are "-" (more than one
+		// "-" could be specified) or no filenames are provided,
+		// then we are only going to be writing to standard out.
+		for (int i = optind; i < argc; i++) {
+			if (strcmp(argv[i], "-") != 0)
+				message_fatal(_("With --format=raw, "
+						"--suffix=.SUF is required "
+						"unless writing to stdout"));
+		}
+	}
+
 	// Compression settings need to be validated (options themselves and
 	// their memory usage) when compressing to any file format. It has to
 	// be done also when uncompressing raw data, since for raw decoding
@@ -727,14 +749,6 @@ args_parse(args_info *args, int argc, char **argv)
 			&& opt_mode != MODE_LIST))
 		coder_set_compression_settings();
 
-	// If raw format is used and a custom suffix is not provided,
-	// then only stdout mode can be used when compressing or decompressing.
-	if (opt_format == FORMAT_RAW && !suffix_is_set() && !opt_stdout
-			&& (opt_mode == MODE_COMPRESS
-				|| opt_mode == MODE_DECOMPRESS))
-		message_fatal(_("With --format=raw, --suffix=.SUF is "
-				"required unless writing to stdout"));
-
 	// If no filenames are given, use stdin.
 	if (argv[optind] == NULL && args->files_name == NULL) {
 		// We don't modify or free() the "-" constant. The caller