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[PATCH] index-pack: eliminate unlimited recursion in get_delta_base()

From
Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Date
Dec 7, 2011, 17:50 UTC
Message-ID
<1323280223-7990-1-git-send-email-pclouds@gmail.com>
In-Reply-To
<7vvcpthh97.fsf@alter.siamese.dyndns.org>

Revert the order of delta applying so that by the time a delta is applied, its base is either non-delta or already inflated. get_delta_base() is still recursive, but because base's data is always ready, the inner get_delta_base() call never has any chance to call itself again.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 builtin/index-pack.c |   30 +++++++++++++++++++++---------
 1 files changed, 21 insertions(+), 9 deletions(-)
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 0945adb..103e19c 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -508,10 +508,25 @@ static void *get_base_data(struct base_data *c)
 {
 	if (!c->data) {
 		struct object_entry *obj = c->obj;
+		struct base_data **delta = NULL;
+		int delta_nr = 0, delta_alloc = 0;
 
-		if (is_delta_type(obj->type)) {
-			void *base = get_base_data(c->base);
-			void *raw = get_data_from_pack(obj);
+		for (; is_delta_type(c->obj->type); c = c->base) {
+			ALLOC_GROW(delta, delta_nr + 1, delta_alloc);
+			delta[delta_nr++] = c;
+		}
+		if (!delta_nr) {
+			c->data = get_data_from_pack(obj);
+			c->size = obj->size;
+			base_cache_used += c->size;
+			prune_base_data(c);
+		}
+		for (; delta_nr > 0; delta_nr--) {
+			void *base, *raw;
+			c = delta[delta_nr - 1];
+			obj = c->obj;
+			base = get_base_data(c->base);
+			raw = get_data_from_pack(obj);
 			c->data = patch_delta(
 				base, c->base->size,
 				raw, obj->size,
@@ -519,13 +534,10 @@ static void *get_base_data(struct base_data *c)
 			free(raw);
 			if (!c->data)
 				bad_object(obj->idx.offset, "failed to apply delta");
-		} else {
-			c->data = get_data_from_pack(obj);
-			c->size = obj->size;
+			base_cache_used += c->size;
+			prune_base_data(c);
 		}
-
-		base_cache_used += c->size;
-		prune_base_data(c);
+		free(delta);
 	}
 	return c->data;
 }
-- 
1.7.8.36.g69ee2
Previous: Junio C HamanoNext: Shawn Pearce
Message 13 of 19 in “Set hard limit on delta chain depth”
  1. Set hard limit on delta chain depthNguyễn Thái Ngọc Duy, Dec 5, 2011
  2. Erik Faye-LundDec 6, 2011
  3. Nguyen Thai Ngoc DuyDec 6, 2011
  4. Erik Faye-LundDec 6, 2011
  5. Nguyen Thai Ngoc DuyDec 6, 2011
  6. Michael HaggertyDec 6, 2011
  7. Nguyen Thai Ngoc DuyDec 6, 2011
  8. Shawn PearceDec 6, 2011
  9. Jeff KingDec 6, 2011
  10. Junio C HamanoDec 6, 2011
  11. Nguyen Thai Ngoc DuyDec 6, 2011
  12. Junio C HamanoDec 10, 2011
  13. index-pack: eliminate unlimited recursion in get_delta_base()Nguyễn Thái Ngọc Duy, Dec 7, 2011
  14. Shawn PearceDec 8, 2011
  15. Nguyen Thai Ngoc DuyDec 8, 2011
  16. 1/2 index_pack: indent find_unresolved_detals one levelpclouds@gmail.com, Dec 8, 2011
  17. Junio C HamanoDec 9, 2011
  18. 2/2 index-pack: a naive attempt to flatten find_unresolved_deltaspclouds@gmail.com, Dec 8, 2011
  19. Shawn PearceDec 8, 2011

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