[PATCH 01/11] Resumable clone: create service git-prime-clone

[Kevin Wern <kevin.m.wern@gmail.com>]

Create git-prime-clone, a program to be executed on the server that
returns the location and type of static resource to download before
performing the rest of a clone.

Additionally, as this executable's location will be configurable (see:
upload-pack and receive-pack), add the program to
BINDIR_PROGRAMS_NEED_X, in addition to the usual builtin places. Add
git-prime-clone executable to gitignore, as well

Signed-off-by: Kevin Wern <kevin.m.wern@gmail.com>
---
 .gitignore                        |  1 +
 Documentation/git-prime-clone.txt | 39 ++++++++++++++++++++
 Makefile                          |  2 +
 builtin.h                         |  1 +
 builtin/prime-clone.c             | 77 +++++++++++++++++++++++++++++++++++++++
 git.c                             |  1 +
 6 files changed, 121 insertions(+)
 create mode 100644 Documentation/git-prime-clone.txt
 create mode 100644 builtin/prime-clone.c

diff --git a/.gitignore b/.gitignore
index 5087ce1..bfea25c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -106,6 +106,7 @@
 /git-pack-refs
 /git-parse-remote
 /git-patch-id
+/git-prime-clone
 /git-prune
 /git-prune-packed
 /git-pull
diff --git a/Documentation/git-prime-clone.txt b/Documentation/git-prime-clone.txt
new file mode 100644
index 0000000..fc5917d
--- /dev/null
+++ b/Documentation/git-prime-clone.txt
@@ -0,0 +1,39 @@
+git-prime-clone(1)
+============
+
+NAME
+----
+git-prime-clone - Get the location of an alternate resource
+to fetch before clone
+
+
+SYNOPSIS
+--------
+[verse]
+'git prime-clone' [--strict] <dir>
+
+DESCRIPTION
+-----------
+
+Outputs the resource, if configured to do so. Otherwise, returns
+nothing (packet flush 0000).
+
+CONFIGURE
+---------
+
+primeclone.url::
+	The full url of the resource (e.g.
+	http://examplehost/pack-$NAME.pack).
+
+primeclone.filetype::
+	The type of the resource (e.g. pack).
+
+primeclone.enabled::
+	When 'false', git-prime-clone will return an empty response,
+	regardless of what the rest of the configuration specifies;
+	otherwise, it will return the configured response. Is 'true'
+	by default.
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Makefile b/Makefile
index 24bef8d..f2564ec 100644
--- a/Makefile
+++ b/Makefile
@@ -648,6 +648,7 @@ OTHER_PROGRAMS = git$X
 # what test wrappers are needed and 'install' will install, in bindir
 BINDIR_PROGRAMS_NEED_X += git
 BINDIR_PROGRAMS_NEED_X += git-upload-pack
+BINDIR_PROGRAMS_NEED_X += git-prime-clone
 BINDIR_PROGRAMS_NEED_X += git-receive-pack
 BINDIR_PROGRAMS_NEED_X += git-upload-archive
 BINDIR_PROGRAMS_NEED_X += git-shell
@@ -904,6 +905,7 @@ BUILTIN_OBJS += builtin/pack-objects.o
 BUILTIN_OBJS += builtin/pack-redundant.o
 BUILTIN_OBJS += builtin/pack-refs.o
 BUILTIN_OBJS += builtin/patch-id.o
+BUILTIN_OBJS += builtin/prime-clone.o
 BUILTIN_OBJS += builtin/prune-packed.o
 BUILTIN_OBJS += builtin/prune.o
 BUILTIN_OBJS += builtin/pull.o
diff --git a/builtin.h b/builtin.h
index 6b95006..c9e2254 100644
--- a/builtin.h
+++ b/builtin.h
@@ -97,6 +97,7 @@ extern int cmd_notes(int argc, const char **argv, const char *prefix);
 extern int cmd_pack_objects(int argc, const char **argv, const char *prefix);
 extern int cmd_pack_redundant(int argc, const char **argv, const char *prefix);
 extern int cmd_patch_id(int argc, const char **argv, const char *prefix);
+extern int cmd_prime_clone(int argc, const char **argv, const char *prefix);
 extern int cmd_prune(int argc, const char **argv, const char *prefix);
 extern int cmd_prune_packed(int argc, const char **argv, const char *prefix);
 extern int cmd_pull(int argc, const char **argv, const char *prefix);
diff --git a/builtin/prime-clone.c b/builtin/prime-clone.c
new file mode 100644
index 0000000..ce914d3
--- /dev/null
+++ b/builtin/prime-clone.c
@@ -0,0 +1,77 @@
+#include "cache.h"
+#include "parse-options.h"
+#include "pkt-line.h"
+
+static char const * const prime_clone_usage[] = {
+	N_("git prime-clone [--strict] <dir>"),
+	NULL
+};
+
+static unsigned int enabled = 1;
+static const char *url = NULL, *filetype = NULL;
+static int strict;
+
+static struct option prime_clone_options[] = {
+	OPT_BOOL(0, "strict", &strict, N_("Do not attempt <dir>/.git if <dir> "
+					  "is not a git directory")),
+	OPT_END(),
+};
+
+static void prime_clone(void)
+{
+	if (!enabled) {
+		fprintf(stderr, _("prime-clone not enabled\n"));
+	}
+	else if (url && filetype){
+		packet_write(1, "%s %s\n", filetype, url);
+	}
+	else if (url || filetype) {
+		if (filetype)
+			fprintf(stderr, _("prime-clone not properly "
+					  "configured: missing url\n"));
+		else if (url)
+			fprintf(stderr, _("prime-clone not properly "
+					  "configured: missing filetype\n"));
+	}
+	packet_flush(1);
+}
+
+static int prime_clone_config(const char *var, const char *value, void *unused)
+{
+	if (!strcmp("primeclone.url",var)) {
+		return git_config_pathname(&url, var, value);
+	}
+	if (!strcmp("primeclone.enabled",var)) {
+		enabled = git_config_bool(var, value);
+		return 0;
+	}
+	if (!strcmp("primeclone.filetype",var)) {
+		return git_config_string(&filetype, var, value);
+	}
+	return git_default_config(var, value, unused);
+}
+
+int cmd_prime_clone(int argc, const char **argv, const char *prefix)
+{
+	const char *dir;
+	argc = parse_options(argc, argv, prefix, prime_clone_options,
+			     prime_clone_usage, 0);
+	if (argc == 0) {
+		usage_msg_opt(_("No repository specified."), prime_clone_usage,
+			      prime_clone_options);
+	}
+	else if (argc > 1) {
+		usage_msg_opt(_("Too many arguments."), prime_clone_usage,
+			      prime_clone_options);
+	}
+
+	dir = argv[0];
+
+	if (!enter_repo(dir, 0)){
+		die(_("'%s' does not appear to be a git repository"), dir);
+	}
+
+	git_config(prime_clone_config, NULL);
+	prime_clone();
+	return 0;
+}
diff --git a/git.c b/git.c
index 6cc0c07..a5681fb 100644
--- a/git.c
+++ b/git.c
@@ -447,6 +447,7 @@ static struct cmd_struct commands[] = {
 	{ "pack-refs", cmd_pack_refs, RUN_SETUP },
 	{ "patch-id", cmd_patch_id },
 	{ "pickaxe", cmd_blame, RUN_SETUP },
+	{ "prime-clone", cmd_prime_clone },
 	{ "prune", cmd_prune, RUN_SETUP },
 	{ "prune-packed", cmd_prune_packed, RUN_SETUP },
 	{ "pull", cmd_pull, RUN_SETUP | NEED_WORK_TREE },
-- 
2.7.4