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* tree-walk: store object_id in a separate memberbrian m. carlson2019-01-151-1/+1
| | | | | | | | | | | | | | | | | When parsing a tree, we read the object ID directly out of the tree buffer. This is normally fine, but such an object ID cannot be used with oidcpy, which copies GIT_MAX_RAWSZ bytes, because if we are using SHA-1, there may not be that many bytes to copy. Instead, store the object ID in a separate struct member. Since we can no longer efficiently compute the path length, store that information as well in struct name_entry. Ensure we only copy the object ID into the new buffer if the path length is nonzero, as some callers will pass us an empty path with no object ID following it, and we will not want to read past the end of the buffer. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* delta-islands.c: remove the_repository referencesNguyễn Thái Ngọc Duy2018-11-121-10/+14
| | | | | Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* pack-objects: move 'layer' into 'struct packing_data'Christian Couder2018-08-161-2/+2
| | | | | | | | | | | | | | This reduces the size of 'struct object_entry' from 88 bytes to 80 and therefore makes packing objects more efficient. For example on a Linux repo with 12M objects, `git pack-objects --all` needs extra 96MB memory even if the layer feature is not used. Helped-by: Jeff King <peff@peff.net> Helped-by: Duy Nguyen <pclouds@gmail.com> Signed-off-by: Christian Couder <chriscool@tuxfamily.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* pack-objects: move tree_depth into 'struct packing_data'Christian Couder2018-08-161-9/+18
| | | | | | | | | | | | | | This reduces the size of 'struct object_entry' and therefore makes packing objects more efficient. This also renames cmp_tree_depth() into tree_depth_compare(), as it is more modern to have the name of the compare functions end with "compare". Helped-by: Jeff King <peff@peff.net> Helped-by: Duy Nguyen <pclouds@gmail.com> Signed-off-by: Christian Couder <chriscool@tuxfamily.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* Add delta-islands.{c,h}Jeff King2018-08-161-0/+493
Hosting providers that allow users to "fork" existing repos want those forks to share as much disk space as possible. Alternates are an existing solution to keep all the objects from all the forks into a unique central repo, but this can have some drawbacks. Especially when packing the central repo, deltas will be created between objects from different forks. This can make cloning or fetching a fork much slower and much more CPU intensive as Git might have to compute new deltas for many objects to avoid sending objects from a different fork. Because the inefficiency primarily arises when an object is deltified against another object that does not exist in the same fork, we partition objects into sets that appear in the same fork, and define "delta islands". When finding delta base, we do not allow an object outside the same island to be considered as its base. So "delta islands" is a way to store objects from different forks in the same repo and packfile without having deltas between objects from different forks. This patch implements the delta islands mechanism in "delta-islands.{c,h}", but does not yet make use of it. A few new fields are added in 'struct object_entry' in "pack-objects.h" though. The documentation will follow in a patch that actually uses delta islands in "builtin/pack-objects.c". Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Christian Couder <chriscool@tuxfamily.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>