upload-archive: allow user to turn off filters

Some tar filters may be very expensive to run, so sites do
not want to expose them via upload-archive. This patch lets
users configure tar.<filter>.remote to turn them off.

By default, gzip filters are left on, as they are about as
expensive as creating zip archives.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-archive.txt

@@ -114,6 +114,12 @@ tar.<format>.command::
 The "tar.gz" and "tgz" formats are defined automatically and default to
 `gzip -cn`. You may override them with custom commands.
 
+tar.<format>.remote::
+	If true, enable `<format>` for use by remote clients via
+	linkgit:git-upload-archive[1]. Defaults to false for
+	user-defined formats, but true for the "tar.gz" and "tgz"
+	formats.
+
 ATTRIBUTES
 ----------
 

archive-tar.c

@@ -274,6 +274,13 @@ static int tar_filter_config(const char *var, const char *value, void *data)
 		ar->data = xstrdup(value);
 		return 0;
 	}
+	if (!strcmp(type, "remote")) {
+		if (git_config_bool(var, value))
+			ar->flags |= ARCHIVER_REMOTE;
+		else
+			ar->flags &= ~ARCHIVER_REMOTE;
+		return 0;
+	}
 
 	return 0;
 }
@@ -349,7 +356,7 @@ static int write_tar_filter_archive(const struct archiver *ar,
 static struct archiver tar_archiver = {
 	"tar",
 	write_tar_archive,
-	0
+	ARCHIVER_REMOTE
 };
 
 void init_tar_archiver(void)
@@ -358,7 +365,9 @@ void init_tar_archiver(void)
 	register_archiver(&tar_archiver);
 
 	tar_filter_config("tar.tgz.command", "gzip -cn", NULL);
+	tar_filter_config("tar.tgz.remote", "true", NULL);
 	tar_filter_config("tar.tar.gz.command", "gzip -cn", NULL);
+	tar_filter_config("tar.tar.gz.remote", "true", NULL);
 	git_config(git_tar_config, NULL);
 	for (i = 0; i < nr_tar_filters; i++) {
 		/* omit any filters that never had a command configured */

archive-zip.c

@@ -283,7 +283,7 @@ static int write_zip_archive(const struct archiver *ar,
 static struct archiver zip_archiver = {
 	"zip",
 	write_zip_archive,
-	ARCHIVER_WANT_COMPRESSION_LEVELS
+	ARCHIVER_WANT_COMPRESSION_LEVELS|ARCHIVER_REMOTE
 };
 
 void init_zip_archiver(void)

archive.c

@@ -299,7 +299,7 @@ static void parse_treeish_arg(const char **argv,
 
 static int parse_archive_args(int argc, const char **argv,
 		const struct archiver **ar, struct archiver_args *args,
-		const char *name_hint)
+		const char *name_hint, int is_remote)
 {
 	const char *format = NULL;
 	const char *base = NULL;
@@ -356,7 +356,8 @@ static int parse_archive_args(int argc, const char **argv,
 
 	if (list) {
 		for (i = 0; i < nr_archivers; i++)
-			printf("%s\n", archivers[i]->name);
+			if (!is_remote || archivers[i]->flags & ARCHIVER_REMOTE)
+				printf("%s\n", archivers[i]->name);
 		exit(0);
 	}
 
@@ -369,7 +370,7 @@ static int parse_archive_args(int argc, const char **argv,
 	if (argc < 1)
 		usage_with_options(archive_usage, opts);
 	*ar = lookup_archiver(format);
-	if (!*ar)
+	if (!*ar || (is_remote && !((*ar)->flags & ARCHIVER_REMOTE)))
 		die("Unknown archive format '%s'", format);
 
 	args->compression_level = Z_DEFAULT_COMPRESSION;
@@ -390,7 +391,7 @@ static int parse_archive_args(int argc, const char **argv,
 }
 
 int write_archive(int argc, const char **argv, const char *prefix,
-		  int setup_prefix, const char *name_hint)
+		  int setup_prefix, const char *name_hint, int remote)
 {
 	int nongit = 0;
 	const struct archiver *ar = NULL;
@@ -403,7 +404,7 @@ int write_archive(int argc, const char **argv, const char *prefix,
 	init_tar_archiver();
 	init_zip_archiver();
 
-	argc = parse_archive_args(argc, argv, &ar, &args, name_hint);
+	argc = parse_archive_args(argc, argv, &ar, &args, name_hint, remote);
 	if (nongit) {
 		/*
 		 * We know this will die() with an error, so we could just

archive.h

@@ -15,6 +15,7 @@ struct archiver_args {
 };
 
 #define ARCHIVER_WANT_COMPRESSION_LEVELS 1
+#define ARCHIVER_REMOTE 2
 struct archiver {
 	const char *name;
 	int (*write_archive)(const struct archiver *, struct archiver_args *);
@@ -29,7 +30,7 @@ extern void init_zip_archiver(void);
 typedef int (*write_archive_entry_fn_t)(struct archiver_args *args, const unsigned char *sha1, const char *path, size_t pathlen, unsigned int mode, void *buffer, unsigned long size);
 
 extern int write_archive_entries(struct archiver_args *args, write_archive_entry_fn_t write_entry);
-extern int write_archive(int argc, const char **argv, const char *prefix, int setup_prefix, const char *name_hint);
+extern int write_archive(int argc, const char **argv, const char *prefix, int setup_prefix, const char *name_hint, int remote);
 
 const char *archive_format_from_filename(const char *filename);
 

builtin/archive.c

@@ -106,5 +106,5 @@ int cmd_archive(int argc, const char **argv, const char *prefix)
 
 	setvbuf(stderr, NULL, _IOLBF, BUFSIZ);
 
-	return write_archive(argc, argv, prefix, 1, output);
+	return write_archive(argc, argv, prefix, 1, output, 0);
 }

builtin/upload-archive.c

@@ -64,7 +64,7 @@ static int run_upload_archive(int argc, const char **argv, const char *prefix)
 	sent_argv[sent_argc] = NULL;
 
 	/* parse all options sent by the client */
-	return write_archive(sent_argc, sent_argv, prefix, 0, NULL);
+	return write_archive(sent_argc, sent_argv, prefix, 0, NULL, 1);
 }
 
 __attribute__((format (printf, 1, 2)))

t/t5000-tar-tree.sh

@@ -256,7 +256,8 @@ test_expect_success 'git-archive --prefix=olde-' '
 
 test_expect_success 'setup tar filters' '
 	git config tar.tar.foo.command "tr ab ba" &&
-	git config tar.bar.command "tr ab ba"
+	git config tar.bar.command "tr ab ba" &&
+	git config tar.bar.remote true
 '
 
 test_expect_success 'archive --list mentions user filter' '
@@ -265,9 +266,9 @@ test_expect_success 'archive --list mentions user filter' '
 	grep "^bar\$" output
 '
 
-test_expect_success 'archive --list shows remote user filters' '
+test_expect_success 'archive --list shows only enabled remote filters' '
 	git archive --list --remote=. >output &&
-	grep "^tar\.foo\$" output &&
+	! grep "^tar\.foo\$" output &&
 	grep "^bar\$" output
 '
 
@@ -297,6 +298,13 @@ test_expect_success 'extension matching requires dot' '
 	test_cmp b.tar config-implicittar.foo
 '
 
+test_expect_success 'only enabled filters are available remotely' '
+	test_must_fail git archive --remote=. --format=tar.foo HEAD \
+		>remote.tar.foo &&
+	git archive --remote=. --format=bar >remote.bar HEAD &&
+	test_cmp remote.bar config.bar
+'
+
 if $GZIP --version >/dev/null 2>&1; then
 	test_set_prereq GZIP
 else
@@ -333,4 +341,15 @@ test_expect_success GZIP,GUNZIP 'extract tgz file' '
 	test_cmp b.tar j.tar
 '
 
+test_expect_success GZIP 'remote tar.gz is allowed by default' '
+	git archive --remote=. --format=tar.gz HEAD >remote.tar.gz &&
+	test_cmp j.tgz remote.tar.gz
+'
+
+test_expect_success GZIP 'remote tar.gz can be disabled' '
+	git config tar.tar.gz.remote false &&
+	test_must_fail git archive --remote=. --format=tar.gz HEAD \
+		>remote.tar.gz
+'
+
 test_done