archive: support compression levels beyond 9

Compression programs like zip, gzip, bzip2 and xz allow to adjust the
trade-off between CPU cost and size gain with numerical options from -1
for fast compression and -9 for high compression ratio.  zip also
accepts -0 for storing files verbatim.  git archive directly support
these single-digit compression levels for ZIP output and passes them to
filters like gzip.

Zstandard additionally supports compression level options -10 to -19, or
up to -22 with --ultra.  This *seems* to work with git archive in most
cases, e.g. it will produce an archive with -19 without complaining, but
since it only supports single-digit compression level options this is
the same as -1 -9 and thus -9.

Allow git archive to accept multi-digit compression levels to support
the full range supported by zstd.  Explicitly reject them for the ZIP
format, as otherwise deflateInit2() would just fail with a somewhat
cryptic "stream consistency error".

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/archive-tar.c b/archive-tar.c
index f1a1447ebda0a11b62cfead71a0f41a22439b392..a971fdc0f6326e0829225d4a2bfe87df48b82a42 100644 (file)
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -374,7 +374,8 @@ static int tar_filter_config(const char *var, const char *value, void *data)
                ar = xcalloc(1, sizeof(*ar));
                ar->name = xmemdupz(name, namelen);
                ar->write_archive = write_tar_filter_archive;
-               ar->flags = ARCHIVER_WANT_COMPRESSION_LEVELS;
+               ar->flags = ARCHIVER_WANT_COMPRESSION_LEVELS |
+                           ARCHIVER_HIGH_COMPRESSION_LEVELS;
                ALLOC_GROW(tar_filters, nr_tar_filters + 1, alloc_tar_filters);
                tar_filters[nr_tar_filters++] = ar;
        }

diff --git a/archive.c b/archive.c
index 3c1541af9e2dfbb9189890beee745bc8574f82fe..7a888c5338bc6ea57621845deadec8549445d6c5 100644 (file)
--- a/archive.c
+++ b/archive.c
@@ -529,10 +529,12 @@ static int add_file_cb(const struct option *opt, const char *arg, int unset)
        return 0;
 }
 
-#define OPT__COMPR(s, v, h, p) \
-       OPT_SET_INT_F(s, NULL, v, h, p, PARSE_OPT_NONEG)
-#define OPT__COMPR_HIDDEN(s, v, p) \
-       OPT_SET_INT_F(s, NULL, v, "", p, PARSE_OPT_NONEG | PARSE_OPT_HIDDEN)
+static int number_callback(const struct option *opt, const char *arg, int unset)
+{
+       BUG_ON_OPT_NEG(unset);
+       *(int *)opt->value = strtol(arg, NULL, 10);
+       return 0;
+}
 
 static int parse_archive_args(int argc, const char **argv,
                const struct archiver **ar, struct archiver_args *args,
@@ -561,16 +563,8 @@ static int parse_archive_args(int argc, const char **argv,
                OPT_BOOL(0, "worktree-attributes", &worktree_attributes,
                        N_("read .gitattributes in working directory")),
                OPT__VERBOSE(&verbose, N_("report archived files on stderr")),
-               OPT__COMPR('0', &compression_level, N_("store only"), 0),
-               OPT__COMPR('1', &compression_level, N_("compress faster"), 1),
-               OPT__COMPR_HIDDEN('2', &compression_level, 2),
-               OPT__COMPR_HIDDEN('3', &compression_level, 3),
-               OPT__COMPR_HIDDEN('4', &compression_level, 4),
-               OPT__COMPR_HIDDEN('5', &compression_level, 5),
-               OPT__COMPR_HIDDEN('6', &compression_level, 6),
-               OPT__COMPR_HIDDEN('7', &compression_level, 7),
-               OPT__COMPR_HIDDEN('8', &compression_level, 8),
-               OPT__COMPR('9', &compression_level, N_("compress better"), 9),
+               OPT_NUMBER_CALLBACK(&compression_level,
+                       N_("set compression level"), number_callback),
                OPT_GROUP(""),
                OPT_BOOL('l', "list", &list,
                        N_("list supported archive formats")),
@@ -617,7 +611,9 @@ static int parse_archive_args(int argc, const char **argv,
 
        args->compression_level = Z_DEFAULT_COMPRESSION;
        if (compression_level != -1) {
-               if ((*ar)->flags & ARCHIVER_WANT_COMPRESSION_LEVELS)
+               int levels_ok = (*ar)->flags & ARCHIVER_WANT_COMPRESSION_LEVELS;
+               int high_ok = (*ar)->flags & ARCHIVER_HIGH_COMPRESSION_LEVELS;
+               if (levels_ok && (compression_level <= 9 || high_ok))
                        args->compression_level = compression_level;
                else {
                        die(_("Argument not supported for format '%s': -%d"),

diff --git a/archive.h b/archive.h
index 82b226011abb60e017cba0bcda355f1a6af6aa5e..e3d04e8ab313d2a86f7c040492999bf43d0874e8 100644 (file)
--- a/archive.h
+++ b/archive.h
@@ -36,6 +36,7 @@ const char *archive_format_from_filename(const char *filename);
 
 #define ARCHIVER_WANT_COMPRESSION_LEVELS 1
 #define ARCHIVER_REMOTE 2
+#define ARCHIVER_HIGH_COMPRESSION_LEVELS 4
 struct archiver {
        const char *name;
        int (*write_archive)(const struct archiver *, struct archiver_args *);