[PATCH 12/17] clone: support --narrow option

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 Documentation/git-clone.txt |   14 +++++++++++++-
 builtin/clone.c             |   43 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 1 deletions(-)

diff --git a/Documentation/git-clone.txt b/Documentation/git-clone.txt
index dc7d3d1..d9a5729 100644
--- a/Documentation/git-clone.txt
+++ b/Documentation/git-clone.txt
@@ -12,7 +12,8 @@ SYNOPSIS
 'git clone' [--template=<template_directory>]
 	  [-l] [-s] [--no-hardlinks] [-q] [-n] [--bare] [--mirror]
 	  [-o <name>] [-b <name>] [-u <upload-pack>] [--reference <repository>]
-	  [--depth <depth>] [--recursive] [--] <repository> [<directory>]
+	  [--depth <depth>] [--narrow <path>] [--recursive]
+	  [--] <repository> [<directory>]
 
 DESCRIPTION
 -----------
@@ -161,6 +162,17 @@ objects from the source repository into a pack in the cloned repository.
 	with a long history, and would want to send in fixes
 	as patches.
 
+--narrow <path>::
+	Create a 'narrow' clone with all commit trees limited to
+	the given path. A narrow repository has a number of
+	limititations (you cannot clone or fech from it, nor push
+	into it), but is adequate if you are only interested in
+	certain paths of a large repository, and would want to
+	push some fixes.
++
+Multiple --narrow can be given. This option can also be used together
+with --depth to truncate both history and path.
+
 --recursive::
 	After the clone is created, initialize all submodules within,
 	using their default settings. This is equivalent to running
diff --git a/builtin/clone.c b/builtin/clone.c
index efb1e6f..439ce8a 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -23,6 +23,7 @@
 #include "branch.h"
 #include "remote.h"
 #include "run-command.h"
+#include "narrow-tree.h"
 
 /*
  * Overall FIXMEs:
@@ -40,11 +41,15 @@ static const char * const builtin_clone_usage[] = {
 static int option_no_checkout, option_bare, option_mirror;
 static int option_local, option_no_hardlinks, option_shared, option_recursive;
 static char *option_template, *option_reference, *option_depth;
+static const char **option_narrow;
 static char *option_origin = NULL;
 static char *option_branch = NULL;
 static char *option_upload_pack = "git-upload-pack";
 static int option_verbosity;
 static int option_progress;
+static int narrow_nr;
+
+static int add_narrow_prefix(const struct option *opt, const char *arg, int unset);
 
 static struct option builtin_clone_options[] = {
 	OPT__VERBOSITY(&option_verbosity),
@@ -78,6 +83,8 @@ static struct option builtin_clone_options[] = {
 		   "path to git-upload-pack on the remote"),
 	OPT_STRING(0, "depth", &option_depth, "depth",
 		    "create a shallow clone of that depth"),
+	OPT_CALLBACK(0, "narrow", NULL, "prefix", "narrow clone",
+		     add_narrow_prefix),
 
 	OPT_END()
 };
@@ -86,6 +93,22 @@ static const char *argv_submodule[] = {
 	"submodule", "update", "--init", "--recursive", NULL
 };
 
+static int add_narrow_prefix(const struct option *opt, const char *arg, int unset)
+{
+	if (unset)
+		die("--no-narrow is not supported");
+
+	narrow_nr++;
+	option_narrow = xrealloc(option_narrow, sizeof(*option_narrow)*narrow_nr);
+	option_narrow[narrow_nr-1] = arg;
+	return 0;
+}
+
+static int narrow_cmp(const void *a, const void *b)
+{
+	return strcmp(*(const char**)a, *(const char **)b);
+}
+
 static char *get_repo_path(const char *repo, int *is_bundle)
 {
 	static char *suffix[] = { "/.git", ".git", "" };
@@ -443,6 +466,14 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 		git_dir = xstrdup(mkpath("%s/.git", dir));
 	}
 
+	if (option_narrow) {
+		int i;
+		qsort(option_narrow, narrow_nr, sizeof(*option_narrow), narrow_cmp);
+		for (i = 0; i < narrow_nr; i++)
+			if (!valid_narrow_prefix(option_narrow[i], i ? option_narrow[i-1] : NULL, 0))
+				die("Invalid narrow prefix");
+	}
+
 	if (!option_bare) {
 		junk_work_tree = work_tree;
 		if (safe_create_leading_directories_const(work_tree) < 0)
@@ -515,6 +546,8 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	strbuf_reset(&value);
 
 	if (path && !is_bundle) {
+		if (option_narrow)
+			die("--narrow is not really for local clone. Please consider --shared");
 		refs = clone_local(path, git_dir);
 		mapped_refs = wanted_peer_refs(refs, refspec);
 	} else {
@@ -530,6 +563,16 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 			transport_set_option(transport, TRANS_OPT_DEPTH,
 					     option_depth);
 
+		/* Do this early in order to set get_narrow_prefix() != NULL */
+		if (option_narrow) {
+			int i;
+			FILE *fp = fopen(git_path("narrow"), "w+");
+			for (i = 0; i < narrow_nr; i++)
+				fprintf(fp, "%s\n", option_narrow[i]);
+			fclose(fp);
+			check_narrow_prefix(); /* Install the prefix */
+		}
+
 		transport_set_verbosity(transport, option_verbosity, option_progress);
 
 		if (option_upload_pack)
-- 
1.7.1.rc1.69.g24c2f7