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2019-09-06pack-objects: drop packlist index_pos optimizationLibravatar Jeff King1-1/+1
Once upon a time, the code to add an object to our packing list in pack-objects all lived in a single function. It computed the position within the hash table once, then used it to check if the object was already present, and if not, to add it. Later, in 2834bc27c1 (pack-objects: refactor the packing list, 2013-10-24), this was split into two functions: packlist_find() and packlist_alloc(). We ended up with an "index_pos" variable that gets passed through several functions to make it from one to the other. The resulting code is rather confusing to follow. The "index_pos" variable is sometimes undefined, if we don't yet have a hash table. This works out in practice because in that case packlist_alloc() won't use it at all, since it will have to create/grow the hash table. But it's hard to verify that, and it does cause gcc 9.2.1's -Wmaybe-uninitialized to complain when compiled with "-flto -O3" (rightfully, since we do pass the uninitialized value as a function parameter, even if nobody ends up using it). All of this is to save computing the hash index again when we're inserting into the hash table, which I found doesn't make a measurable difference in the program runtime (which is not surprising, since we're doing all kinds of other heavyweight things for each object). Let's just drop this index_pos variable entirely, simplifying the code (and pleasing the compiler). We might be better still refactoring this custom hash table to use one of our existing implementations (an oidmap, or a kh_oid_map). I stopped short of that here, but this would be the likely first step towards that anyway. Reported-by: Stephan Beyer <s-beyer@gmx.net> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-20pack-bitmap: convert khash_sha1 maps into kh_oid_mapLibravatar Jeff King1-7/+7
All of the users of our khash_sha1 maps actually have a "struct object_id". Let's use the more descriptive type. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-20pack-objects: convert packlist_find() to use object_idLibravatar Jeff King1-1/+1
We take a raw hash pointer, but most of our callers have a "struct object_id" already. Let's switch to taking the full struct, which will let us continue removing uses of raw sha1 buffers. There are two callers that do need special attention: - in rebuild_existing_bitmaps(), we need to switch to nth_packed_object_oid(). This incurs an extra hash copy over pointing straight to the mmap'd sha1, but it shouldn't be measurable compared to the rest of the operation. - in can_reuse_delta() we already spent the effort to copy the sha1 into a "struct object_id", but now we just have to do so a little earlier in the function (we can't easily convert that function's callers because they may be pointing at mmap'd REF_DELTA blocks). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-20pack-bitmap-write: convert some helpers to use object_idLibravatar Jeff King1-9/+9
A few functions take raw hash pointers, but all of their callers actually have a "struct object_id". Let's retain that extra type as long as possible (which will let future patches extend that further, and so on). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-01pack-bitmap: replace sha1_to_hexLibravatar brian m. carlson1-3/+3
Replace the uses of sha1_to_hex in the pack bitmap code with hash_to_hex to allow the use of SHA-256 as well. Rename a few variables since they are no longer limited to SHA-1. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-01pack-bitmap: make bitmap header handling hash agnosticLibravatar brian m. carlson1-1/+1
Increase the checksum field in struct bitmap_disk_header to be GIT_MAX_RAWSZ bytes in length and ensure that we hash the proper number of bytes out when computing the bitmap checksum. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-12pack-*.c: remove the_repository referencesLibravatar Nguyễn Thái Ngọc Duy1-3/+3
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-10-30Merge branch 'bc/hash-transition-part-15'Libravatar Junio C Hamano1-1/+1
More codepaths are moving away from hardcoded hash sizes. * bc/hash-transition-part-15: rerere: convert to use the_hash_algo submodule: make zero-oid comparison hash function agnostic apply: rename new_sha1_prefix and old_sha1_prefix apply: replace hard-coded constants tag: express constant in terms of the_hash_algo transport: use parse_oid_hex instead of a constant upload-pack: express constants in terms of the_hash_algo refs/packed-backend: express constants using the_hash_algo packfile: express constants in terms of the_hash_algo pack-revindex: express constants in terms of the_hash_algo builtin/fetch-pack: remove constants with parse_oid_hex builtin/mktree: remove hard-coded constant builtin/repack: replace hard-coded constants pack-bitmap-write: use GIT_MAX_RAWSZ for allocation object_id.cocci: match only expressions of type 'struct object_id'
2018-10-19Merge branch 'nd/the-index'Libravatar Junio C Hamano1-1/+1
Various codepaths in the core-ish part learn to work on an arbitrary in-core index structure, not necessarily the default instance "the_index". * nd/the-index: (23 commits) revision.c: reduce implicit dependency the_repository revision.c: remove implicit dependency on the_index ws.c: remove implicit dependency on the_index tree-diff.c: remove implicit dependency on the_index submodule.c: remove implicit dependency on the_index line-range.c: remove implicit dependency on the_index userdiff.c: remove implicit dependency on the_index rerere.c: remove implicit dependency on the_index sha1-file.c: remove implicit dependency on the_index patch-ids.c: remove implicit dependency on the_index merge.c: remove implicit dependency on the_index merge-blobs.c: remove implicit dependency on the_index ll-merge.c: remove implicit dependency on the_index diff-lib.c: remove implicit dependency on the_index read-cache.c: remove implicit dependency on the_index diff.c: remove implicit dependency on the_index grep.c: remove implicit dependency on the_index diff.c: remove the_index dependency in textconv() functions blame.c: rename "repo" argument to "r" combine-diff.c: remove implicit dependency on the_index ...
2018-10-15pack-bitmap-write: use GIT_MAX_RAWSZ for allocationLibravatar brian m. carlson1-1/+1
Reviewed-by: Stefan Beller <sbeller@google.com> Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-21revision.c: remove implicit dependency on the_indexLibravatar Nguyễn Thái Ngọc Duy1-1/+1
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-17Merge branch 'ds/reachable'Libravatar Junio C Hamano1-0/+1
The code for computing history reachability has been shuffled, obtained a bunch of new tests to cover them, and then being improved. * ds/reachable: commit-reach: correct accidental #include of C file commit-reach: use can_all_from_reach commit-reach: make can_all_from_reach... linear commit-reach: replace ref_newer logic test-reach: test commit_contains test-reach: test can_all_from_reach_with_flags test-reach: test reduce_heads test-reach: test get_merge_bases_many test-reach: test is_descendant_of test-reach: test in_merge_bases test-reach: create new test tool for ref_newer commit-reach: move can_all_from_reach_with_flags upload-pack: generalize commit date cutoff upload-pack: refactor ok_to_give_up() upload-pack: make reachable() more generic commit-reach: move commit_contains from ref-filter commit-reach: move ref_newer from remote.c commit.h: remove method declarations commit-reach: move walk methods from commit.c
2018-07-20commit.h: remove method declarationsLibravatar Derrick Stolee1-0/+1
These methods are now declared in commit-reach.h. Remove them from commit.h and add new include statements in all files that require these declarations. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-18Merge branch 'jt/remove-pack-bitmap-global'Libravatar Junio C Hamano1-2/+8
The effort to move globals to per-repository in-core structure continues. * jt/remove-pack-bitmap-global: pack-bitmap: add free function pack-bitmap: remove bitmap_git global variable
2018-07-18Merge branch 'sb/object-store-grafts'Libravatar Junio C Hamano1-0/+1
The conversion to pass "the_repository" and then "a_repository" throughout the object access API continues. * sb/object-store-grafts: commit: allow lookup_commit_graft to handle arbitrary repositories commit: allow prepare_commit_graft to handle arbitrary repositories shallow: migrate shallow information into the object parser path.c: migrate global git_path_* to take a repository argument cache: convert get_graft_file to handle arbitrary repositories commit: convert read_graft_file to handle arbitrary repositories commit: convert register_commit_graft to handle arbitrary repositories commit: convert commit_graft_pos() to handle arbitrary repositories shallow: add repository argument to is_repository_shallow shallow: add repository argument to check_shallow_file_for_update shallow: add repository argument to register_shallow shallow: add repository argument to set_alternate_shallow_file commit: add repository argument to lookup_commit_graft commit: add repository argument to prepare_commit_graft commit: add repository argument to read_graft_file commit: add repository argument to register_commit_graft commit: add repository argument to commit_graft_pos object: move grafts to object parser object-store: move object access functions to object-store.h
2018-06-29Merge branch 'sb/object-store-grafts' into sb/object-store-lookupLibravatar Junio C Hamano1-0/+1
* sb/object-store-grafts: commit: allow lookup_commit_graft to handle arbitrary repositories commit: allow prepare_commit_graft to handle arbitrary repositories shallow: migrate shallow information into the object parser path.c: migrate global git_path_* to take a repository argument cache: convert get_graft_file to handle arbitrary repositories commit: convert read_graft_file to handle arbitrary repositories commit: convert register_commit_graft to handle arbitrary repositories commit: convert commit_graft_pos() to handle arbitrary repositories shallow: add repository argument to is_repository_shallow shallow: add repository argument to check_shallow_file_for_update shallow: add repository argument to register_shallow shallow: add repository argument to set_alternate_shallow_file commit: add repository argument to lookup_commit_graft commit: add repository argument to prepare_commit_graft commit: add repository argument to read_graft_file commit: add repository argument to register_commit_graft commit: add repository argument to commit_graft_pos object: move grafts to object parser object-store: move object access functions to object-store.h
2018-06-21pack-bitmap: add free functionLibravatar Jonathan Tan1-0/+4
Add a function to free struct bitmap_index instances, and use it where needed (except when rebuild_existing_bitmaps() is used, since it creates references to the bitmaps within the struct bitmap_index passed to it). Note that the hashes field in struct bitmap_index is not freed because it points to another field within the same struct. The documentation for that field has been updated to clarify that. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-06-21pack-bitmap: remove bitmap_git global variableLibravatar Jonathan Tan1-2/+4
Remove the bitmap_git global variable. Instead, generate on demand an instance of struct bitmap_index for code that needs to access it. This allows us significant control over the lifetime of instances of struct bitmap_index. In particular, packs can now be closed without worrying if an unnecessarily long-lived "pack" field in struct bitmap_index still points to it. The bitmap API is also clearer in that we need to first obtain a struct bitmap_index, then we use it. This patch raises two potential issues: (1) memory for the struct bitmap_index is allocated without being freed, and (2) prepare_bitmap_git() and prepare_bitmap_walk() can reuse a previously loaded bitmap. For (1), this will be dealt with in a subsequent patch in this patch set that also deals with freeing the contents of the struct bitmap_index (which were not freed previously, because they have global scope). For (2), current bitmap users only load the bitmap once at most (note that pack-objects can use bitmaps or write bitmaps, but not both at the same time), so support for reuse has no effect - and future users can pass around the struct bitmap_index * obtained if they need to do 2 or more things with the same bitmap. Helped-by: Stefan Beller <sbeller@google.com> Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Helped-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-05-30Merge branch 'js/use-bug-macro'Libravatar Junio C Hamano1-1/+1
Developer support update, by using BUG() macro instead of die() to mark codepaths that should not happen more clearly. * js/use-bug-macro: BUG_exit_code: fix sparse "symbol not declared" warning Convert remaining die*(BUG) messages Replace all die("BUG: ...") calls by BUG() ones run-command: use BUG() to report bugs, not die() test-tool: help verifying BUG() code paths
2018-05-23Merge branch 'nd/pack-objects-pack-struct'Libravatar Junio C Hamano1-6/+8
"git pack-objects" needs to allocate tons of "struct object_entry" while doing its work, and shrinking its size helps the performance quite a bit. * nd/pack-objects-pack-struct: ci: exercise the whole test suite with uncommon code in pack-objects pack-objects: reorder members to shrink struct object_entry pack-objects: shrink delta_size field in struct object_entry pack-objects: shrink size field in struct object_entry pack-objects: clarify the use of object_entry::size pack-objects: don't check size when the object is bad pack-objects: shrink z_delta_size field in struct object_entry pack-objects: refer to delta objects by index instead of pointer pack-objects: move in_pack out of struct object_entry pack-objects: move in_pack_pos out of struct object_entry pack-objects: use bitfield for object_entry::depth pack-objects: use bitfield for object_entry::dfs_state pack-objects: turn type and in_pack_type to bitfields pack-objects: a bit of document about struct object_entry read-cache.c: make $GIT_TEST_SPLIT_INDEX boolean
2018-05-23Merge branch 'sb/oid-object-info'Libravatar Junio C Hamano1-1/+2
The codepath around object-info API has been taught to take the repository object (which in turn tells the API which object store the objects are to be located). * sb/oid-object-info: cache.h: allow oid_object_info to handle arbitrary repositories packfile: add repository argument to cache_or_unpack_entry packfile: add repository argument to unpack_entry packfile: add repository argument to read_object packfile: add repository argument to packed_object_info packfile: add repository argument to packed_to_object_type packfile: add repository argument to retry_bad_packed_offset cache.h: add repository argument to oid_object_info cache.h: add repository argument to oid_object_info_extended
2018-05-16object-store: move object access functions to object-store.hLibravatar Stefan Beller1-0/+1
This should make these functions easier to find and cache.h less overwhelming to read. In particular, this moves: - read_object_file - oid_object_info - write_object_file As a result, most of the codebase needs to #include object-store.h. In this patch the #include is only added to files that would fail to compile otherwise. It would be better to #include wherever identifiers from the header are used. That can happen later when we have better tooling for it. Signed-off-by: Stefan Beller <sbeller@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-05-08Merge branch 'ds/commit-graph'Libravatar Junio C Hamano1-1/+1
Precompute and store information necessary for ancestry traversal in a separate file to optimize graph walking. * ds/commit-graph: commit-graph: implement "--append" option commit-graph: build graph from starting commits commit-graph: read only from specific pack-indexes commit: integrate commit graph with commit parsing commit-graph: close under reachability commit-graph: add core.commitGraph setting commit-graph: implement git commit-graph read commit-graph: implement git-commit-graph write commit-graph: implement write_commit_graph() commit-graph: create git-commit-graph builtin graph: add commit graph design document commit-graph: add format document csum-file: refactor finalize_hashfile() method csum-file: rename hashclose() to finalize_hashfile()
2018-05-06Replace all die("BUG: ...") calls by BUG() onesLibravatar Johannes Schindelin1-1/+1
In d8193743e08 (usage.c: add BUG() function, 2017-05-12), a new macro was introduced to use for reporting bugs instead of die(). It was then subsequently used to convert one single caller in 588a538ae55 (setup_git_env: convert die("BUG") to BUG(), 2017-05-12). The cover letter of the patch series containing this patch (cf 20170513032414.mfrwabt4hovujde2@sigill.intra.peff.net) is not terribly clear why only one call site was converted, or what the plan is for other, similar calls to die() to report bugs. Let's just convert all remaining ones in one fell swoop. This trick was performed by this invocation: sed -i 's/die("BUG: /BUG("/g' $(git grep -l 'die("BUG' \*.c) Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-26cache.h: add repository argument to oid_object_infoLibravatar Stefan Beller1-1/+2
Add a repository argument to allow the callers of oid_object_info to be more specific about which repository to handle. This is a small mechanical change; it doesn't change the implementation to handle repositories other than the_repository yet. As with the previous commits, use a macro to catch callers passing a repository other than the_repository at compile time. Signed-off-by: Stefan Beller <sbeller@google.com> Reviewed-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-16pack-objects: move in_pack_pos out of struct object_entryLibravatar Nguyễn Thái Ngọc Duy1-3/+5
This field is only need for pack-bitmap, which is an optional feature. Move it to a separate array that is only allocated when pack-bitmap is used (like objects[], it is not freed, since we need it until the end of the process) Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-16pack-objects: turn type and in_pack_type to bitfieldsLibravatar Nguyễn Thái Ngọc Duy1-3/+3
An extra field type_valid is added to carry the equivalent of OBJ_BAD in the original "type" field. in_pack_type always contains a valid type so we only need 3 bits for it. A note about accepting OBJ_NONE as "valid" type. The function read_object_list_from_stdin() can pass this value [1] and it eventually calls create_object_entry() where current code skip setting "type" field if the incoming type is zero. This does not have any bad side effects because "type" field should be memset()'d anyway. But since we also need to set type_valid now, skipping oe_set_type() leaves type_valid zero/false, which will make oe_type() return OBJ_BAD, not OBJ_NONE anymore. Apparently we do care about OBJ_NONE in prepare_pack(). This switch from OBJ_NONE to OBJ_BAD may trigger fatal: unable to get type of object ... Accepting OBJ_NONE [2] does sound wrong, but this is how it is has been for a very long time and I haven't time to dig in further. [1] See 5c49c11686 (pack-objects: better check_object() performances - 2007-04-16) [2] 21666f1aae (convert object type handling from a string to a number - 2007-02-26) Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-02csum-file: refactor finalize_hashfile() methodLibravatar Derrick Stolee1-1/+1
If we want to use a hashfile on the temporary file for a lockfile, then we need finalize_hashfile() to fully write the trailing hash but also keep the file descriptor open. Do this by adding a new CSUM_HASH_IN_STREAM flag along with a functional change that checks this flag before writing the checksum to the stream. This differs from previous behavior since it would be written if either CSUM_CLOSE or CSUM_FSYNC is provided. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-02csum-file: rename hashclose() to finalize_hashfile()Libravatar Derrick Stolee1-1/+1
The hashclose() method behaves very differently depending on the flags parameter. In particular, the file descriptor is not always closed. Perform a simple rename of "hashclose()" to "finalize_hashfile()" in preparation for functional changes. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-03-14sha1_file: convert sha1_object_info* to object_idLibravatar brian m. carlson1-2/+1
Convert sha1_object_info and sha1_object_info_extended to take pointers to struct object_id and rename them to use "oid" instead of "sha1" in their names. Update the declaration and definition and apply the following semantic patch, plus the standard object_id transforms: @@ expression E1, E2; @@ - sha1_object_info(E1.hash, E2) + oid_object_info(&E1, E2) @@ expression E1, E2; @@ - sha1_object_info(E1->hash, E2) + oid_object_info(E1, E2) @@ expression E1, E2, E3; @@ - sha1_object_info_extended(E1.hash, E2, E3) + oid_object_info_extended(&E1, E2, E3) @@ expression E1, E2, E3; @@ - sha1_object_info_extended(E1->hash, E2, E3) + oid_object_info_extended(E1, E2, E3) Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-02-02csum-file: rename sha1file to hashfileLibravatar brian m. carlson1-15/+15
Rename struct sha1file to struct hashfile, along with all of its related functions. The transformation in this commit was made by global search-and-replace. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-24pack-bitmap[-write]: use `object_array_clear()`, don't leakLibravatar Martin Ågren1-3/+1
Instead of setting the fields of rev->pending to 0/NULL, thereby leaking memory, call `object_array_clear(&rev->pending)`. In pack-bitmap.c, we make copies of those fields as `pending_nr` and `pending_e`. We never update the aliases and the original fields never change, so the aliases are not really needed and just make it harder than necessary to understand the code. While we're here, remove the aliases to make the code easier to follow. Signed-off-by: Martin Ågren <martin.agren@gmail.com> Reviewed-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-08pack: convert struct pack_idx_entry to struct object_idLibravatar brian m. carlson1-3/+5
Convert struct pack_idx_entry to use struct object_id by changing the definition and applying the following semantic patch, plus the standard object_id transforms: @@ struct pack_idx_entry E1; @@ - E1.sha1 + E1.oid.hash @@ struct pack_idx_entry *E1; @@ - E1->sha1 + E1->oid.hash Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-28odb_mkstemp: write filename into strbufLibravatar Jeff King1-5/+7
The odb_mkstemp() function expects the caller to provide a fixed buffer to write the resulting tempfile name into. But it creates the template using snprintf without checking the return value. This means we could silently truncate the filename. In practice, it's unlikely that the truncation would end in the template-pattern that mkstemp needs to open the file. So we'd probably end up failing either way, unless the path was specially crafted. The simplest fix would be to notice the truncation and die. However, we can observe that most callers immediately xstrdup() the result anyway. So instead, let's switch to using a strbuf, which is easier for them (and isn't a big deal for the other 2 callers, who can just strbuf_release when they're done with it). Note that many of the callers used static buffers, but this was purely to avoid putting a large buffer on the stack. We never passed the static buffers out of the function, so there's no complicated memory handling we need to change. Signed-off-by: Jeff King <peff@peff.net>
2017-03-28do not check odb_mkstemp return value for errorsLibravatar Jeff King1-2/+0
The odb_mkstemp function does not return an error; it dies on failure instead. But many of its callers compare the resulting descriptor against -1 and die themselves. Mostly this is just pointless, but it does raise a question when looking at the callers: if they show the results of the "template" buffer after a failure, what's in it? The answer is: it doesn't matter, because it cannot happen. So let's make that clear by removing the bogus error checks. In bitmap_writer_finish(), we can drop the error-handling code entirely. In the other two cases, it's shared with the open() in another code path; we can just move the error-check next to that open() call. And while we're at it, let's flesh out the function's docstring a bit to make the error behavior clear. Signed-off-by: Jeff King <peff@peff.net>
2016-09-29use QSORTLibravatar René Scharfe1-2/+1
Apply the semantic patch contrib/coccinelle/qsort.cocci to the code base, replacing calls of qsort(3) with QSORT. The resulting code is shorter and supports empty arrays with NULL pointers. Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-02-12list-objects: pass full pathname to callbacksLibravatar Jeff King1-2/+1
When we find a blob at "a/b/c", we currently pass this to our show_object_fn callbacks as two components: "a/b/" and "c". Callbacks which want the full value then call path_name(), which concatenates the two. But this is an inefficient interface; the path is a strbuf, and we could simply append "c" to it temporarily, then roll back the length, without creating a new copy. So we could improve this by teaching the callsites of path_name() this trick (and there are only 3). But we can also notice that no callback actually cares about the broken-down representation, and simply pass each callback the full path "a/b/c" as a string. The callback code becomes even simpler, then, as we do not have to worry about freeing an allocated buffer, nor rolling back our modification to the strbuf. This is theoretically less efficient, as some callbacks would not bother to format the final path component. But in practice this is not measurable. Since we use the same strbuf over and over, our work to grow it is amortized, and we really only pay to memcpy a few bytes. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-02-12list-objects: drop name_path entirelyLibravatar Jeff King1-1/+1
In the previous commit, we left name_path as a thin wrapper around a strbuf. This patch drops it entirely. As a result, every show_object_fn callback needs to be adjusted. However, none of their code needs to be changed at all, because the only use was to pass it to path_name(), which now handles the bare strbuf. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-11-20Remove get_object_hash.Libravatar brian m. carlson1-7/+7
Convert all instances of get_object_hash to use an appropriate reference to the hash member of the oid member of struct object. This provides no functional change, as it is essentially a macro substitution. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Jeff King <peff@peff.net>
2015-11-20Convert struct object to object_idLibravatar brian m. carlson1-1/+1
struct object is one of the major data structures dealing with object IDs. Convert it to use struct object_id instead of an unsigned char array. Convert get_object_hash to refer to the new member as well. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Jeff King <peff@peff.net>
2015-11-20Add several uses of get_object_hash.Libravatar brian m. carlson1-7/+7
Convert most instances where the sha1 member of struct object is dereferenced to use get_object_hash. Most instances that are passed to functions that have versions taking struct object_id, such as get_sha1_hex/get_oid_hex, or instances that can be trivially converted to use struct object_id instead, are not converted. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Jeff King <peff@peff.net>
2014-12-12Merge branch 'jk/pack-bitmap'Libravatar Junio C Hamano1-5/+3
* jk/pack-bitmap: pack-bitmap: do not use gcc packed attribute
2014-11-30pack-bitmap: do not use gcc packed attributeLibravatar Karsten Blees1-5/+3
The "__attribute__" flag may be a noop on some compilers. That's OK as long as the code is correct without the attribute, but in this case it is not. We would typically end up with a struct that is 2 bytes too long due to struct padding, breaking both reading and writing of bitmaps. Instead of marshalling the data in a struct, let's just provide helpers for reading and writing the appropriate types. Besides being correct on all platforms, the result is more efficient and simpler to read. Signed-off-by: Karsten Blees <blees@dcon.de> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-09-18use REALLOC_ARRAY for changing the allocation size of arraysLibravatar René Scharfe1-2/+1
Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-03-06Use hashcpy() when copying object namesLibravatar Sun He1-1/+1
We invented hashcpy() to keep the abstraction of "object name" behind it. Use it instead of calling memcpy() with hard-coded 20-byte length when moving object names between pieces of memory. Leave ppc/sha1.c as-is, because the function is about the SHA-1 hash algorithm whose output is and will always be 20 bytes. Helped-by: Michael Haggerty <mhagger@alum.mit.edu> Helped-by: Duy Nguyen <pclouds@gmail.com> Signed-off-by: Sun He <sunheehnus@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-30pack-bitmap: implement optional name_hash cacheLibravatar Vicent Marti1-2/+19
When we use pack bitmaps rather than walking the object graph, we end up with the list of objects to include in the packfile, but we do not know the path at which any tree or blob objects would be found. In a recently packed repository, this is fine. A fetch would use the paths only as a heuristic in the delta compression phase, and a fully packed repository should not need to do much delta compression. As time passes, though, we may acquire more objects on top of our large bitmapped pack. If clients fetch frequently, then they never even look at the bitmapped history, and all works as usual. However, a client who has not fetched since the last bitmap repack will have "have" tips in the bitmapped history, but "want" newer objects. The bitmaps themselves degrade gracefully in this circumstance. We manually walk the more recent bits of history, and then use bitmaps when we hit them. But we would also like to perform delta compression between the newer objects and the bitmapped objects (both to delta against what we know the user already has, but also between "new" and "old" objects that the user is fetching). The lack of pathnames makes our delta heuristics much less effective. This patch adds an optional cache of the 32-bit name_hash values to the end of the bitmap file. If present, a reader can use it to match bitmapped and non-bitmapped names during delta compression. Here are perf results for p5310: Test origin/master HEAD^ HEAD ------------------------------------------------------------------------------------------------- 5310.2: repack to disk 36.81(37.82+1.43) 47.70(48.74+1.41) +29.6% 47.75(48.70+1.51) +29.7% 5310.3: simulated clone 30.78(29.70+2.14) 1.08(0.97+0.10) -96.5% 1.07(0.94+0.12) -96.5% 5310.4: simulated fetch 3.16(6.10+0.08) 3.54(10.65+0.06) +12.0% 1.70(3.07+0.06) -46.2% 5310.6: partial bitmap 36.76(43.19+1.81) 6.71(11.25+0.76) -81.7% 4.08(6.26+0.46) -88.9% You can see that the time spent on an incremental fetch goes down, as our delta heuristics are able to do their work. And we save time on the partial bitmap clone for the same reason. Signed-off-by: Vicent Marti <tanoku@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-30pack-objects: implement bitmap writingLibravatar Vicent Marti1-0/+535
This commit extends more the functionality of `pack-objects` by allowing it to write out a `.bitmap` index next to any written packs, together with the `.idx` index that currently gets written. If bitmap writing is enabled for a given repository (either by calling `pack-objects` with the `--write-bitmap-index` flag or by having `pack.writebitmaps` set to `true` in the config) and pack-objects is writing a packfile that would normally be indexed (i.e. not piping to stdout), we will attempt to write the corresponding bitmap index for the packfile. Bitmap index writing happens after the packfile and its index has been successfully written to disk (`finish_tmp_packfile`). The process is performed in several steps: 1. `bitmap_writer_set_checksum`: this call stores the partial checksum for the packfile being written; the checksum will be written in the resulting bitmap index to verify its integrity 2. `bitmap_writer_build_type_index`: this call uses the array of `struct object_entry` that has just been sorted when writing out the actual packfile index to disk to generate 4 type-index bitmaps (one for each object type). These bitmaps have their nth bit set if the given object is of the bitmap's type. E.g. the nth bit of the Commits bitmap will be 1 if the nth object in the packfile index is a commit. This is a very cheap operation because the bitmap writing code has access to the metadata stored in the `struct object_entry` array, and hence the real type for each object in the packfile. 3. `bitmap_writer_reuse_bitmaps`: if there exists an existing bitmap index for one of the packfiles we're trying to repack, this call will efficiently rebuild the existing bitmaps so they can be reused on the new index. All the existing bitmaps will be stored in a `reuse` hash table, and the commit selection phase will prioritize these when selecting, as they can be written directly to the new index without having to perform a revision walk to fill the bitmap. This can greatly speed up the repack of a repository that already has bitmaps. 4. `bitmap_writer_select_commits`: if bitmap writing is enabled for a given `pack-objects` run, the sequence of commits generated during the Counting Objects phase will be stored in an array. We then use that array to build up the list of selected commits. Writing a bitmap in the index for each object in the repository would be cost-prohibitive, so we use a simple heuristic to pick the commits that will be indexed with bitmaps. The current heuristics are a simplified version of JGit's original implementation. We select a higher density of commits depending on their age: the 100 most recent commits are always selected, after that we pick 1 commit of each 100, and the gap increases as the commits grow older. On top of that, we make sure that every single branch that has not been merged (all the tips that would be required from a clone) gets their own bitmap, and when selecting commits between a gap, we tend to prioritize the commit with the most parents. Do note that there is no right/wrong way to perform commit selection; different selection algorithms will result in different commits being selected, but there's no such thing as "missing a commit". The bitmap walker algorithm implemented in `prepare_bitmap_walk` is able to adapt to missing bitmaps by performing manual walks that complete the bitmap: the ideal selection algorithm, however, would select the commits that are more likely to be used as roots for a walk in the future (e.g. the tips of each branch, and so on) to ensure a bitmap for them is always available. 5. `bitmap_writer_build`: this is the computationally expensive part of bitmap generation. Based on the list of commits that were selected in the previous step, we perform several incremental walks to generate the bitmap for each commit. The walks begin from the oldest commit, and are built up incrementally for each branch. E.g. consider this dag where A, B, C, D, E, F are the selected commits, and a, b, c, e are a chunk of simplified history that will not receive bitmaps. A---a---B--b--C--c--D \ E--e--F We start by building the bitmap for A, using A as the root for a revision walk and marking all the objects that are reachable until the walk is over. Once this bitmap is stored, we reuse the bitmap walker to perform the walk for B, assuming that once we reach A again, the walk will be terminated because A has already been SEEN on the previous walk. This process is repeated for C, and D, but when we try to generate the bitmaps for E, we can reuse neither the current walk nor the bitmap we have generated so far. What we do now is resetting both the walk and clearing the bitmap, and performing the walk from scratch using E as the origin. This new walk, however, does not need to be completed. Once we hit B, we can lookup the bitmap we have already stored for that commit and OR it with the existing bitmap we've composed so far, allowing us to limit the walk early. After all the bitmaps have been generated, another iteration through the list of commits is performed to find the best XOR offsets for compression before writing them to disk. Because of the incremental nature of these bitmaps, XORing one of them with its predecesor results in a minimal "bitmap delta" most of the time. We can write this delta to the on-disk bitmap index, and then re-compose the original bitmaps by XORing them again when loaded. This is a phase very similar to pack-object's `find_delta` (using bitmaps instead of objects, of course), except the heuristics have been greatly simplified: we only check the 10 bitmaps before any given one to find best compressing one. This gives good results in practice, because there is locality in the ordering of the objects (and therefore bitmaps) in the packfile. 6. `bitmap_writer_finish`: the last step in the process is serializing to disk all the bitmap data that has been generated in the two previous steps. The bitmap is written to a tmp file and then moved atomically to its final destination, using the same process as `pack-write.c:write_idx_file`. Signed-off-by: Vicent Marti <tanoku@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>