[PATCH 16/20] upload-pack: support define shallow boundary by excluding revisions

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

This should allow the user to say "create a shallow clone of this branch
after version <some-tag>".

deepen-not cannot be used with deepen the same way deepen-since cannot
be used with deepen. But deepen-not can be mixed with deepen-since. The
result is exactly how you do the command "git rev-list --since=... --not
ref".

FIXME: restrict dwim_ref. Access to reflog at server side may not be a
good idea. Either that or force the user to specify full ref names at
client side (a bit annoying).

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 Documentation/technical/pack-protocol.txt         |  3 ++-
 Documentation/technical/protocol-capabilities.txt |  9 +++++++++
 upload-pack.c                                     | 24 +++++++++++++++++++++--
 3 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/Documentation/technical/pack-protocol.txt b/Documentation/technical/pack-protocol.txt
index 9251df1..dee33a6 100644
--- a/Documentation/technical/pack-protocol.txt
+++ b/Documentation/technical/pack-protocol.txt
@@ -220,7 +220,8 @@ out of what the server said it could do with the first 'want' line.
   shallow-line      =  PKT-LINE("shallow" SP obj-id)
 
   depth-request     =  PKT-LINE("deepen" SP depth) /
-		       PKT-LINE("deepen-since" SP timestamp)
+		       PKT-LINE("deepen-since" SP timestamp) /
+		       PKT-LINE("deepen-not" SP ref)
 
   first-want        =  PKT-LINE("want" SP obj-id SP capability-list)
   additional-want   =  PKT-LINE("want" SP obj-id)
diff --git a/Documentation/technical/protocol-capabilities.txt b/Documentation/technical/protocol-capabilities.txt
index f08cc4e..0e6b57d 100644
--- a/Documentation/technical/protocol-capabilities.txt
+++ b/Documentation/technical/protocol-capabilities.txt
@@ -188,6 +188,15 @@ specific time, instead of depth. Internally it's equivalent of doing
 "rev-list --max-age=<timestamp>" on the server side. "deepen-since"
 cannot be used with "deepen".
 
+deepen-not
+----------
+
+This capability adds "deepen-not" command to fetch-pack/upload-pack
+protocol so the client can request shallow clones that are cut at a
+specific revision, instead of depth. Internally it's equivalent of
+doing "rev-list --not <rev>" on the server side. "deepen-not"
+cannot be used with "deepen", but can be used with "deepen-since".
+
 no-progress
 -----------
 
diff --git a/upload-pack.c b/upload-pack.c
index 100b604..90ecb5b 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -617,6 +617,7 @@ static void deepen_by_rev_list(int ac, const char **av,
 static void receive_needs(void)
 {
 	struct object_array shallows = OBJECT_ARRAY_INIT;
+	struct string_list deepen_not = STRING_LIST_INIT_DUP;
 	int depth = 0;
 	int has_non_tip = 0;
 	unsigned long deepen_since = 0;
@@ -667,6 +668,18 @@ static void receive_needs(void)
 			deepen_rev_list = 1;
 			continue;
 		}
+		if (skip_prefix(line, "deepen-not ", &arg)) {
+			char *ref = NULL;
+			unsigned char sha1[20];
+			if (dwim_ref(arg, strlen(arg), sha1, &ref) != 1)
+				die("Ambiguous deepen-not: %s", line);
+			if (!ref || check_refname_format(ref, 0))
+				die("Invalid deepen-not: %s", line);
+			string_list_append(&deepen_not, ref);
+			free(ref);
+			deepen_rev_list = 1;
+			continue;
+		}
 		if (!skip_prefix(line, "want ", &arg) ||
 		    get_sha1_hex(arg, sha1_buf))
 			die("git upload-pack: protocol error, "
@@ -721,7 +734,7 @@ static void receive_needs(void)
 	if (depth == 0 && !deepen_rev_list && shallows.nr == 0)
 		return;
 	if (depth > 0 && deepen_rev_list)
-		die("--depth and --since cannot be used together");
+		die("--depth and --since (or --not) cannot be used together");
 	if (depth > 0)
 		deepen(depth, &shallows);
 	else if (deepen_rev_list) {
@@ -735,6 +748,13 @@ static void receive_needs(void)
 			struct object *o = want_obj.objects[i].item;
 			argv_array_push(&av, oid_to_hex(&o->oid));
 		}
+		if (deepen_not.nr) {
+			argv_array_push(&av, "--not");
+			for (i = 0; i < deepen_not.nr; i++) {
+				struct string_list_item *s = deepen_not.items + i;
+				argv_array_push(&av, s->string);
+			}
+		}
 		deepen_by_rev_list(av.argc, av.argv, &shallows);
 		argv_array_clear(&av);
 	}
@@ -786,7 +806,7 @@ static int send_ref(const char *refname, const struct object_id *oid,
 		    int flag, void *cb_data)
 {
 	static const char *capabilities = "multi_ack thin-pack side-band"
-		" side-band-64k ofs-delta shallow deepen-since no-progress"
+		" side-band-64k ofs-delta shallow deepen-since deepen-not no-progress"
 		" include-tag multi_ack_detailed";
 	const char *refname_nons = strip_namespace(refname);
 	struct object_id peeled;
-- 
2.3.0.rc1.137.g477eb31