dpkg-deb: shorten code, improve help text

function                                             old     new   delta
packed_usage                                       30261   30236     -25
dpkg_deb_main                                        437     401     -36
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-61)             Total: -61 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 34 insertions, 43 deletions

diff --git a/archival/dpkg_deb.c b/archival/dpkg_deb.c
index d34de254a..86850469d 100644
--- a/archival/dpkg_deb.c
+++ b/archival/dpkg_deb.c
@@ -22,14 +22,14 @@
 //kbuild:lib-$(CONFIG_DPKG_DEB) += dpkg_deb.o
 
 //usage:#define dpkg_deb_trivial_usage
-//usage:       "[-cefxX] FILE [argument]"
+//usage:       "[-cefxX] FILE [DIR]"
 //usage:#define dpkg_deb_full_usage "\n\n"
-//usage:       "Perform actions on Debian packages (.debs)\n"
-//usage:     "\n        -c      List contents of filesystem tree"
-//usage:     "\n        -e      Extract control files to [argument] directory"
-//usage:     "\n        -f      Display control field name starting with [argument]"
-//usage:     "\n        -x      Extract packages filesystem tree to directory"
-//usage:     "\n        -X      Verbose extract"
+//usage:       "Perform actions on Debian packages (.deb)\n"
+//usage:     "\n        -c      List files"
+//usage:     "\n        -f      Print control fields"
+//usage:     "\n        -e      Extract control files to DIR (default: ./DEBIAN)"
+//usage:     "\n        -x      Extract files to DIR (no default)"
+//usage:     "\n        -X      Verbose -x"
 //usage:
 //usage:#define dpkg_deb_example_usage
 //usage:       "$ dpkg-deb -X ./busybox_0.48-1_i386.deb /tmp\n"
@@ -40,18 +40,17 @@
 #define DPKG_DEB_OPT_CONTENTS         1
 #define DPKG_DEB_OPT_CONTROL          2
 #define DPKG_DEB_OPT_FIELD            4
-#define DPKG_DEB_OPT_EXTRACT          8
-#define DPKG_DEB_OPT_EXTRACT_VERBOSE 16
+#define DPKG_DEB_OPT_EXTRACT_VERBOSE  8
+#define DPKG_DEB_OPT_EXTRACT         16
 
 int dpkg_deb_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int dpkg_deb_main(int argc, char **argv)
+int dpkg_deb_main(int argc UNUSED_PARAM, char **argv)
 {
         archive_handle_t *ar_archive;
         archive_handle_t *tar_archive;
         llist_t *control_tar_llist = NULL;
         unsigned opt;
         const char *extract_dir;
-        int need_args;
 
         /* Setup the tar archive handle */
         tar_archive = init_handle();
@@ -80,53 +79,45 @@ int dpkg_deb_main(int argc, char **argv)
         llist_add_to(&control_tar_llist, (char*)"control.tar.xz");
 #endif
 
-        opt_complementary = "c--efXx:e--cfXx:f--ceXx:X--cefx:x--cefX";
+        /* Must have 1 or 2 args */
+        opt_complementary = "-1:?2:c--efXx:e--cfXx:f--ceXx:X--cefx:x--cefX";
         opt = getopt32(argv, "cefXx");
         argv += optind;
-        argc -= optind;
+        //argc -= optind;
 
-        if (opt & DPKG_DEB_OPT_CONTENTS) {
+        extract_dir = argv[1];
+        if (opt & DPKG_DEB_OPT_CONTENTS) { // -c
                 tar_archive->action_header = header_verbose_list;
+                if (extract_dir)
+                        bb_show_usage();
         }
-        extract_dir = NULL;
-        need_args = 1;
-        if (opt & DPKG_DEB_OPT_CONTROL) {
-                ar_archive->accept = control_tar_llist;
-                tar_archive->action_data = data_extract_all;
-                if (1 == argc) {
-                        extract_dir = "./DEBIAN";
-                } else {
-                        need_args++;
-                }
-        }
-        if (opt & DPKG_DEB_OPT_FIELD) {
-                /* Print the entire control file
-                 * it should accept a second argument which specifies a
-                 * specific field to print */
+        if (opt & DPKG_DEB_OPT_FIELD) { // -f
+                /* Print the entire control file */
+//TODO: standard tool accepts an optional list of fields to print
                 ar_archive->accept = control_tar_llist;
                 llist_add_to(&(tar_archive->accept), (char*)"./control");
                 tar_archive->filter = filter_accept_list;
                 tar_archive->action_data = data_extract_to_stdout;
+                if (extract_dir)
+                        bb_show_usage();
         }
-        if (opt & DPKG_DEB_OPT_EXTRACT) {
-                tar_archive->action_header = header_list;
-        }
-        if (opt & (DPKG_DEB_OPT_EXTRACT_VERBOSE | DPKG_DEB_OPT_EXTRACT)) {
+        if (opt & DPKG_DEB_OPT_CONTROL) { // -e
+                ar_archive->accept = control_tar_llist;
                 tar_archive->action_data = data_extract_all;
-                need_args = 2;
+                if (!extract_dir)
+                        extract_dir = "./DEBIAN";
         }
-
-        if (need_args != argc) {
-                bb_show_usage();
+        if (opt & (DPKG_DEB_OPT_EXTRACT_VERBOSE | DPKG_DEB_OPT_EXTRACT)) { // -Xx
+                if (opt & DPKG_DEB_OPT_EXTRACT_VERBOSE)
+                        tar_archive->action_header = header_list;
+                tar_archive->action_data = data_extract_all;
+                if (!extract_dir)
+                        bb_show_usage();
         }
 
-        tar_archive->src_fd = ar_archive->src_fd = xopen(argv[0], O_RDONLY);
+        /* Standard tool supports "-" */
+        tar_archive->src_fd = ar_archive->src_fd = xopen_stdin(argv[0]);
 
-        /* Work out where to extract the files */
-        /* 2nd argument is a dir name */
-        if (argv[1]) {
-                extract_dir = argv[1];
-        }
         if (extract_dir) {
                 mkdir(extract_dir, 0777); /* bb_make_directory(extract_dir, 0777, 0) */
                 xchdir(extract_dir);