[PATCH] add: add --bulk to index all objects into a pack file

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

The use case is

    tar -xzf bigproject.tar.gz
    cd bigproject
    git init
    git add .
    # git grep or something

The first add will generate a bunch of loose objects. With --bulk, all
of them are forced into a single pack instead, less clutter on disk
and maybe faster object access.

This is the equivalent of "git -c core.bigFileThreshold=0 add ." so
it's not really a new functionality. Just some convenient and public
exposure.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 Interestingly index_stream() seems a bit slower than standard
 index_core(). Perhaps mmap() is faster than a series of read() for
 small files. Room for improvement later.

 Documentation/git-add.txt |  6 ++++++
 builtin/add.c             | 10 +++++++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/Documentation/git-add.txt b/Documentation/git-add.txt
index 48754cb..36a77f6 100644
--- a/Documentation/git-add.txt
+++ b/Documentation/git-add.txt
@@ -160,6 +160,12 @@ today's "git add <pathspec>...", ignoring removed files.
 	be ignored, no matter if they are already present in the work
 	tree or not.
 
+--bulk::
+	Normally new objects are indexed and stored in loose format,
+	one file per new object in "$GIT_DIR/objects". This option
+	forces putting all objects into a single new pack. This may
+	be useful when you need to add a lot of files initially.
+
 \--::
 	This option can be used to separate command-line options from
 	the list of files, (useful when filenames might be mistaken
diff --git a/builtin/add.c b/builtin/add.c
index 226f758..40cbb71 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -336,7 +336,7 @@ static struct lock_file lock_file;
 static const char ignore_error[] =
 N_("The following paths are ignored by one of your .gitignore files:\n");
 
-static int verbose, show_only, ignored_too, refresh_only;
+static int verbose, show_only, ignored_too, refresh_only, bulk_index;
 static int ignore_add_errors, intent_to_add, ignore_missing;
 
 #define ADDREMOVE_DEFAULT 0 /* Change to 1 in Git 2.0 */
@@ -368,6 +368,7 @@ static struct option builtin_add_options[] = {
 	OPT_BOOL( 0 , "refresh", &refresh_only, N_("don't add, only refresh the index")),
 	OPT_BOOL( 0 , "ignore-errors", &ignore_add_errors, N_("just skip files which cannot be added because of errors")),
 	OPT_BOOL( 0 , "ignore-missing", &ignore_missing, N_("check if - even missing - files are ignored in dry run")),
+	OPT_BOOL( 0 , "bulk", &bulk_index, N_("pack all objects instead of creating loose ones")),
 	OPT_END(),
 };
 
@@ -560,6 +561,13 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 		free(seen);
 	}
 
+	if (bulk_index)
+		/*
+		 * Pretend all blobs are "large" files, forcing them
+		 * all into a pack
+		 */
+		big_file_threshold = 0;
+
 	plug_bulk_checkin();
 
 	if ((flags & ADD_CACHE_IMPLICIT_DOT) && prefix) {
-- 
1.8.2.82.gc24b958