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[PATCH v2 3/6] log: make the intent of cmd_show()'s "rev.pending" juggling clearer

From
Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date
Jul 29, 2022, 08:31 UTC
Message-ID
<patch-v2-3.6-1629299f883-20220729T082919Z-avarab@gmail.com>
In-Reply-To
<cover-v2-0.6-00000000000-20220729T082919Z-avarab@gmail.com>

Adjust code added in 5d7eeee2ac6 (git-show: grok blobs, trees and tags, too, 2006-12-14) to use the "memcpy a &blank" idiom introduced in 5726a6b4012 (*.c *_init(): define in terms of corresponding *_INIT macro, 2021-07-01).

Now the types in play are guaranteed to correspond, i.e. we used "int" here for the "count" before, but the corresponding "nr" is an "unsigned int". By using a "blank" object we almost entirely bypass that, we'll only need to declare our own "unsigned int i".

There are no functional changes here aside from potential overflow guard rails, the structure only has these three members ("nr", "alloc" and "objects"), but now we're obviously future-proof against assuming that.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 builtin/log.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/builtin/log.c b/builtin/log.c
index 88a5e98875a..6135f8191a9 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -668,10 +668,12 @@ static void show_setup_revisions_tweak(struct rev_info *rev,
 int cmd_show(int argc, const char **argv, const char *prefix)
 {
 	struct rev_info rev;
-	struct object_array_entry *objects;
+	struct object_array blank = OBJECT_ARRAY_INIT;
+	struct object_array pending = OBJECT_ARRAY_INIT;
+	unsigned int i;
 	struct setup_revision_opt opt;
 	struct pathspec match_all;
-	int i, count, ret = 0;
+	int ret = 0;
 
 	init_log_defaults();
 	git_config(git_log_config, NULL);
@@ -698,12 +700,11 @@ int cmd_show(int argc, const char **argv, const char *prefix)
 	if (!rev.no_walk)
 		return cmd_log_deinit(cmd_log_walk(&rev), &rev);
 
-	count = rev.pending.nr;
-	objects = rev.pending.objects;
+	memcpy(&pending, &rev.pending, sizeof(rev.pending));
 	rev.diffopt.no_free = 1;
-	for (i = 0; i < count && !ret; i++) {
-		struct object *o = objects[i].item;
-		const char *name = objects[i].name;
+	for (i = 0; i < pending.nr && !ret; i++) {
+		struct object *o = pending.objects[i].item;
+		const char *name = pending.objects[i].name;
 		switch (o->type) {
 		case OBJ_BLOB:
 			ret = show_blob_object(&o->oid, &rev, name);
@@ -726,7 +727,7 @@ int cmd_show(int argc, const char **argv, const char *prefix)
 			if (!o)
 				ret = error(_("could not read object %s"),
 					    oid_to_hex(oid));
-			objects[i].item = o;
+			pending.objects[i].item = o;
 			i--;
 			break;
 		}
@@ -743,8 +744,7 @@ int cmd_show(int argc, const char **argv, const char *prefix)
 			rev.shown_one = 1;
 			break;
 		case OBJ_COMMIT:
-			rev.pending.nr = rev.pending.alloc = 0;
-			rev.pending.objects = NULL;
+			memcpy(&rev.pending, &blank, sizeof(rev.pending));
 			add_object_array(o, name, &rev.pending);
 			ret = cmd_log_walk_no_free(&rev);
 			break;
-- 
2.37.1.1196.g8af3636bc64
Previous: Eric SunshineNext: Junio C Hamano
Message 25 of 52 in “revisions API: fix more memory leaks”
  1. 0/6 revisions API: fix more memory leaksÆvar Arnfjörð Bjarmason, Jul 13, 2022
  2. 1/6 bisect.c: add missing "goto" for release_revisions()Ævar Arnfjörð Bjarmason, Jul 13, 2022
  3. 2/6 test-fast-rebase helper: use release_revisions() (again)Ævar Arnfjörð Bjarmason, Jul 13, 2022
  4. 3/6 log: make the intent of cmd_show()'s "rev.pending" juggling clearerÆvar Arnfjörð Bjarmason, Jul 13, 2022
  5. Jeff KingJul 18, 2022
  6. 4/6 log: fix common "rev.pending" memory leak in "git show"Ævar Arnfjörð Bjarmason, Jul 13, 2022
  7. Jeff KingJul 18, 2022
  8. Ævar Arnfjörð BjarmasonJul 18, 2022
  9. 5/6 bisect.c: partially fix bisect_rev_setup() memory leakÆvar Arnfjörð Bjarmason, Jul 13, 2022
  10. Jeff KingJul 18, 2022
  11. 6/6 revisions API: don't leak memory on argv elements that need free()-ingÆvar Arnfjörð Bjarmason, Jul 13, 2022
  12. Jeff KingJul 18, 2022
  13. Ævar Arnfjörð BjarmasonJul 18, 2022
  14. Jeff KingJul 18, 2022
  15. Ævar Arnfjörð BjarmasonJul 29, 2022
  16. Jeff KingJul 29, 2022
  17. Jeff KingJul 29, 2022
  18. Junio C HamanoJul 29, 2022
  19. Jeff KingJul 29, 2022
  20. Jeff KingJul 18, 2022
  21. 0/6 revisions API: fix more memory leaksÆvar Arnfjörð Bjarmason, Jul 29, 2022
  22. 1/6 bisect.c: add missing "goto" for release_revisions()Ævar Arnfjörð Bjarmason, Jul 29, 2022
  23. 2/6 test-fast-rebase helper: use release_revisions() (again)Ævar Arnfjörð Bjarmason, Jul 29, 2022
  24. Eric SunshineJul 30, 2022
  25. 3/6 log: make the intent of cmd_show()'s "rev.pending" juggling clearerÆvar Arnfjörð Bjarmason, Jul 29, 2022
  26. Junio C HamanoJul 29, 2022
  27. 4/6 log: fix common "rev.pending" memory leak in "git show"Ævar Arnfjörð Bjarmason, Jul 29, 2022
  28. Jeff KingJul 29, 2022
  29. Jeff KingJul 29, 2022
  30. Jeff KingJul 29, 2022
  31. 5/6 bisect.c: partially fix bisect_rev_setup() memory leakÆvar Arnfjörð Bjarmason, Jul 29, 2022
  32. 6/6 revisions API: don't leak memory on argv elements that need free()-ingÆvar Arnfjörð Bjarmason, Jul 29, 2022
  33. Jeff KingJul 29, 2022
  34. Jeff KingJul 29, 2022
  35. 0/6 revisions API: fix more memory leaksÆvar Arnfjörð Bjarmason, Aug 2, 2022
  36. 1/6 bisect.c: add missing "goto" for release_revisions()Ævar Arnfjörð Bjarmason, Aug 2, 2022
  37. Junio C HamanoAug 3, 2022
  38. 2/6 test-fast-rebase helper: use release_revisions() (again)Ævar Arnfjörð Bjarmason, Aug 2, 2022
  39. 3/6 log: fix a memory leak in "git show <revision>..."Ævar Arnfjörð Bjarmason, Aug 2, 2022
  40. Jeff KingAug 3, 2022
  41. Jeff KingAug 3, 2022
  42. Junio C HamanoAug 3, 2022
  43. 5/6 bisect.c: partially fix bisect_rev_setup() memory leakÆvar Arnfjörð Bjarmason, Aug 2, 2022
  44. 4/6 log: refactor "rev.pending" code in cmd_show()Ævar Arnfjörð Bjarmason, Aug 2, 2022
  45. Jeff KingAug 3, 2022
  46. Junio C HamanoAug 3, 2022
  47. Ævar Arnfjörð BjarmasonAug 4, 2022
  48. Junio C HamanoAug 4, 2022
  49. Ævar Arnfjörð BjarmasonAug 5, 2022
  50. 6/6 revisions API: don't leak memory on argv elements that need free()-ingÆvar Arnfjörð Bjarmason, Aug 2, 2022
  51. Junio C HamanoAug 3, 2022
  52. Jeff KingAug 3, 2022

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