Existing callers provide the reverse index code with an array of 'struct
pack_idx_entry *'s, which is then sorted by pack order (comparing the
offsets of each object within the pack).
Prepare for the multi-pack index to write a .rev file by providing a way
to write the reverse index without an array of pack_idx_entry (which the
MIDX code does not have).
Instead, callers can invoke 'write_rev_index_positions()', which takes
an array of uint32_t's. The ith entry in this array specifies the ith
object's (in index order) position within the pack (in pack order).
Expose this new function for use in a later patch, and rewrite the
existing write_rev_file() in terms of this new function.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Implement reading for multi-pack reverse indexes, as described in the
previous patch.
Note that these functions don't yet have any callers, and won't until
multi-pack reachability bitmaps are introduced in a later patch series.
In the meantime, this patch implements some of the infrastructure
necessary to support multi-pack bitmaps.
There are three new functions exposed by the revindex API:
- load_midx_revindex(): loads the reverse index corresponding to the
given multi-pack index.
- midx_to_pack_pos() and pack_pos_to_midx(): these convert between the
multi-pack index and pseudo-pack order.
load_midx_revindex() and pack_pos_to_midx() are both relatively
straightforward.
load_midx_revindex() needs a few functions to be exposed from the midx
API. One to get the checksum of a midx, and another to get the .rev's
filename. Similar to recent changes in the packed_git struct, three new
fields are added to the multi_pack_index struct: one to keep track of
the size, one to keep track of the mmap'd pointer, and another to point
past the header and at the reverse index's data.
pack_pos_to_midx() simply reads the corresponding entry out of the
table.
midx_to_pack_pos() is the trickiest, since it needs to find an object's
position in the psuedo-pack order, but that order can only be recovered
in the .rev file itself. This mapping can be implemented with a binary
search, but note that the thing we're binary searching over isn't an
array of values, but rather a permuted order of those values.
So, when comparing two items, it's helpful to keep in mind the
difference. Instead of a traditional binary search, where you are
comparing two things directly, here we're comparing a (pack, offset)
tuple with an index into the multi-pack index. That index describes
another (pack, offset) tuple, and it is _those_ two tuples that are
compared.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As a prerequisite to implementing multi-pack bitmaps, motivate and
describe the format and ordering of the multi-pack reverse index.
The subsequent patch will implement reading this format, and the patch
after that will implement writing it while producing a multi-pack index.
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In a subsequent commit, pack-revindex.c will become responsible for
sorting a list of objects in the "MIDX pack order" (which will be
defined in the following patch). To do so, it will need to be know the
pack identifier and offset within that pack for each object in the MIDX.
The MIDX code already has functions for doing just that
(nth_midxed_offset() and nth_midxed_pack_int_id()), but they are
statically declared.
Since there is no reason that they couldn't be exposed publicly, and
because they are already doing exactly what the caller in
pack-revindex.c will want, expose them publicly so that they can be
reused there.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
write_midx_internal() uses a hashfile to write the multi-pack index, but
discards its checksum. This makes sense, since nothing that takes place
after writing the MIDX cares about its checksum.
That is about to change in a subsequent patch, when the optional
reverse index corresponding to the MIDX will want to include the MIDX's
checksum.
Store the checksum of the MIDX in preparation for that.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A subsequent patch will need to refer back to 'midx_name' later on in
the function. In fact, this variable is already free()'d later on, so
this makes the later free() no longer redundant.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When multiple packs in the multi-pack index contain the same object, the
MIDX machinery must make a choice about which pack it associates with
that object. Prior to this patch, the lowest-ordered[1] pack was always
selected.
Pack selection for duplicate objects is relatively unimportant today,
but it will become important for multi-pack bitmaps. This is because we
can only invoke the pack-reuse mechanism when all of the bits for reused
objects come from the reuse pack (in order to ensure that all reused
deltas can find their base objects in the same pack).
To encourage the pack selection process to prefer one pack over another
(the pack to be preferred is the one a caller would like to later use as
a reuse pack), introduce the concept of a "preferred pack". When
provided, the MIDX code will always prefer an object found in a
preferred pack over any other.
No format changes are required to store the preferred pack, since it
will be able to be inferred with a corresponding MIDX bitmap, by looking
up the pack associated with the object in the first bit position (this
ordering is described in detail in a subsequent commit).
[1]: the ordering is specified by MIDX internals; for our purposes we
can consider the "lowest ordered" pack to be "the one with the
most-recent mtime.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The 'read-midx' helper is used in places like t5319 to display basic
information about a multi-pack-index.
In the next patch, the MIDX writing machinery will learn a new way to
choose from which pack an object is selected when multiple copies of
that object exist.
To disambiguate which pack introduces an object so that this feature can
be tested, add a '--show-objects' option which displays additional
information about each object in the MIDX.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When given a sub-command that it doesn't understand, 'git
multi-pack-index' dies with the following message:
$ git multi-pack-index bogus
fatal: unrecognized subcommand: bogus
Instead of 'die()'-ing, we can display the usage text, which is much
more helpful:
$ git.compile multi-pack-index bogus
error: unrecognized subcommand: bogus
usage: git multi-pack-index [<options>] write
or: git multi-pack-index [<options>] verify
or: git multi-pack-index [<options>] expire
or: git multi-pack-index [<options>] repack [--batch-size=<size>]
--object-dir <file> object directory containing set of packfile and pack-index pairs
--progress force progress reporting
While we're at it, clean up some duplication between the "no sub-command"
and "unrecognized sub-command" conditionals.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Even before the recent refactoring, 'git multi-pack-index' calls
'trace2_cmd_mode()' before verifying that the sub-command is recognized.
Push this call down into the individual sub-commands so that we don't
enter a bogus command mode.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Handle sub-commands of the 'git multi-pack-index' builtin (e.g.,
"write", "repack", etc.) separately from one another. This allows
sub-commands with unique options, without forcing cmd_multi_pack_index()
to reject invalid combinations itself.
This comes at the cost of some duplication and boilerplate. Luckily, the
duplication is reduced to a minimum, since common options are shared
among sub-commands due to a suggestion by Ævar. (Sub-commands do have to
retain the common options, too, since this builtin accepts common
options on either side of the sub-command).
Roughly speaking, cmd_multi_pack_index() parses options (including
common ones), and stops at the first non-option, which is the
sub-command. It then dispatches to the appropriate sub-command, which
parses the remaining options (also including common options).
Unknown options are kept by the sub-commands in order to detect their
presence (and complain that too many arguments were given).
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Factor out the usage message into pieces corresponding to each mode.
This avoids options specific to one sub-command from being shared with
another in the usage.
A subsequent commit will use these #define macros to have usage
variables for each sub-command without duplicating their contents.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that there is a shared 'flags' member in the options structure,
there is no need to keep track of whether to force progress or not,
since ultimately the decision of whether or not to show a progress meter
is controlled by a bit in the flags member.
Manipulate that bit directly, and drop the now-unnecessary 'progress'
field while we're at it.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Subcommands of the 'git multi-pack-index' command (e.g., 'write',
'verify', etc.) will want to optionally change a set of shared flags
that are eventually passed to the MIDX libraries.
Right now, options and flags are handled separately. That's fine, since
the options structure is never passed around. But a future patch will
make it so that common options shared by all sub-commands are defined in
a common location. That means that "flags" would have to become a global
variable.
Group it with the options structure so that we reduce the number of
global variables we have overall.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* ds/chunked-file-api:
commit-graph.c: display correct number of chunks when writing
chunk-format: add technical docs
chunk-format: restore duplicate chunk checks
midx: use 64-bit multiplication for chunk sizes
midx: use chunk-format read API
commit-graph: use chunk-format read API
chunk-format: create read chunk API
midx: use chunk-format API in write_midx_internal()
midx: drop chunk progress during write
midx: return success/failure in chunk write methods
midx: add num_large_offsets to write_midx_context
midx: add pack_perm to write_midx_context
midx: add entries to write_midx_context
midx: use context in write_midx_pack_names()
midx: rename pack_info to write_midx_context
commit-graph: use chunk-format write API
chunk-format: create chunk format write API
commit-graph: anonymize data in chunk_write_fn
When writing a commit-graph, a progress meter is shown which indicates
the number of pieces of data to write (one per commit in each chunk).
In 47410aa837 (commit-graph: use chunk-format write API, 2021-02-18),
the number of chunks became tracked by the new chunk-format API. But a
stray local variable was left behind from when write_commit_graph_file()
used to keep track of the same.
Since this was no longer updated after 47410aa837, the progress meter
appeared broken:
$ git commit-graph write --reachable
Expanding reachable commits in commit graph: 837569, done.
Writing out commit graph in 3 passes: 166% (4187845/2512707), done.
Drop the local variable and rely instead on the chunk-format API to tell
us the correct number of chunks.
Reported-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Acked-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Test framework clean-up.
* ab/test-lib:
test-lib-functions: assert correct parameter count
test-lib-functions: remove bug-inducing "diagnostics" helper param
test libs: rename "diff-lib" to "lib-diff"
t/.gitattributes: sort lines
test-lib-functions: move function to lib-bitmap.sh
test libs: rename gitweb-lib.sh to lib-gitweb.sh
test libs: rename bundle helper to "lib-bundle.sh"
test-lib-functions: remove generate_zero_bytes() wrapper
test-lib-functions: move test_set_index_version() to its user
test lib: change "error" to "BUG" as appropriate
test-lib: remove check_var_migration
A small memleak in "diff -I<regexp>" has been corrected.
* ab/diff-deferred-free:
diff: plug memory leak from regcomp() on {log,diff} -I
diff: add an API for deferred freeing
When a pager spawned by us exited, the trace log did not record its
exit status correctly, which has been corrected.
* ab/pager-exit-log:
pager: properly log pager exit code when signalled
run-command: add braces for "if" block in wait_or_whine()
pager: test for exit code with and without SIGPIPE
pager: refactor wait_for_pager() function
Update formatting and grammar of the hash transition plan
documentation, plus some updates.
* ta/hash-function-transition-doc:
doc: use https links
doc hash-function-transition: move rationale upwards
doc hash-function-transition: fix incomplete sentence
doc hash-function-transition: use upper case consistently
doc hash-function-transition: use SHA-1 and SHA-256 consistently
doc hash-function-transition: fix asciidoc output
Signed commits and tags now allow verification of objects, whose
two object names (one in SHA-1, the other in SHA-256) are both
signed.
* bc/signed-objects-with-both-hashes:
gpg-interface: remove other signature headers before verifying
ref-filter: hoist signature parsing
commit: allow parsing arbitrary buffers with headers
gpg-interface: improve interface for parsing tags
commit: ignore additional signatures when parsing signed commits
ref-filter: switch some uses of unsigned long to size_t
Documentation, code and test clean-up around "git stash".
* dl/stash-cleanup:
stash: declare ref_stash as an array
t3905: use test_cmp() to check file contents
t3905: replace test -s with test_file_not_empty
t3905: remove nested git in command substitution
t3905: move all commands into test cases
t3905: remove spaces after redirect operators
git-stash.txt: be explicit about subcommand options
The chunk-based file format is now an API in the code, but we should
also take time to document it as a file format. Specifically, it matches
the CHUNK LOOKUP sections of the commit-graph and multi-pack-index
files, but there are some commonalities that should be grouped in this
document.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Before refactoring into the chunk-format API, the commit-graph parsing
logic included checks for duplicate chunks. It is unlikely that we would
desire a chunk-based file format that allows duplicate chunk IDs in the
table of contents, so add duplicate checks into
read_table_of_contents().
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When calculating the sizes of certain chunks, we should use 64-bit
multiplication always. This allows us to properly predict the chunk
sizes without risk of overflow.
Other possible overflows were discovered by evaluating each
multiplication in midx.c and ensuring that at least one side of the
operator was of type size_t or off_t.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of parsing the table of contents directly, use the chunk-format
API methods read_table_of_contents() and pair_chunk(). In particular, we
can use the return value of pair_chunk() to generate an error when a
required chunk is missing.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of parsing the table of contents directly, use the chunk-format
API methods read_table_of_contents() and pair_chunk(). While the current
implementation loses the duplicate-chunk detection, that will be added
in a future change.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add the capability to read the table of contents, then pair the chunks
with necessary logic using read_chunk_fn pointers. Callers will be added
in future changes, but the typical outline will be:
1. initialize a 'struct chunkfile' with init_chunkfile(NULL).
2. call read_table_of_contents().
3. for each chunk to parse,
a. call pair_chunk() to assign a pointer with the chunk position, or
b. call read_chunk() to run a callback on the chunk start and size.
4. call free_chunkfile() to clear the 'struct chunkfile' data.
We are re-using the anonymous 'struct chunkfile' data, as it is internal
to the chunk-format API. This gives it essentially two modes: write and
read. If the same struct instance was used for both reads and writes,
then there would be failures.
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The chunk-format API allows writing the table of contents and all chunks
using the anonymous 'struct chunkfile' type. We only need to convert our
local chunk logic to this API for the multi-pack-index writes to share
that logic with the commit-graph file writes.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Most expensive operations in write_midx_internal() use the context
struct's progress member, and these indicate the process of the
expensive operations within the chunk writing methods. However, there is
a competing progress struct that counts the progress over all chunks.
This is not very helpful compared to the others, so drop it.
This also reduces our barriers to combining the chunk writing code with
chunk-format.c.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Historically, the chunk-writing methods in midx.c have returned the
amount of data written so the writer method could compare this with the
table of contents. This presents with some interesting issues:
1. If a chunk writing method has a bug that miscalculates the written
bytes, then we can satisfy the table of contents without actually
writing the right amount of data to the hashfile. The commit-graph
writing code checks the hashfile struct directly for a more robust
verification.
2. There is no way for a chunk writing method to gracefully fail.
Returning an int presents an opportunity to fail without a die().
3. The current pattern doesn't match chunk_write_fn type exactly, so we
cannot share code with commit-graph.c
For these reasons, convert the midx chunk writer methods to return an
'int'. Since none of them fail at the moment, they all return 0.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In an effort to align write_midx_internal() with the chunk-format API,
continue to group necessary data into "struct write_midx_context". This
change collects the "uint32_t num_large_offsets" into the context. With
this new data, write_midx_large_offsets() now matches the
chunk_write_fn type.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In an effort to align write_midx_internal() with the chunk-format API,
continue to group necessary data into "struct write_midx_context". This
change collects the "uint32_t *pack_perm" and large_offsets_needed bit
into the context.
Update write_midx_object_offsets() to match chunk_write_fn.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In an effort to align write_midx_internal() with the chunk-format API,
continue to group necessary data into "struct write_midx_context". This
change collects the "struct pack_midx_entry *entries" list and its count
into the context.
Update write_midx_oid_fanout() and write_midx_oid_lookup() to take the
context directly, as these are easy conversions with this new data.
Only the callers of write_midx_object_offsets() and
write_midx_large_offsets() are updated here, since additional data in
the context before those methods can match chunk_write_fn.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In an effort to align the write_midx_internal() to use the chunk-format
API, start converting chunk writing methods to match chunk_write_fn. The
first case is to convert write_midx_pack_names() to take "void *data".
We already have the necessary data in "struct write_midx_context", so
this conversion is rather mechanical.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In an effort to streamline our chunk-based file formats, align some of
the code structure in write_midx_internal() to be similar to the
patterns in write_commit_graph_file().
Specifically, let's create a "struct write_midx_context" that can be
used as a data parameter to abstract function types.
This change only renames "struct pack_info" to "struct
write_midx_context" and the names of instances from "packs" to "ctx". In
future changes, we will expand the data inside "struct
write_midx_context" and align our chunk-writing method with the
chunk-format API.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The commit-graph write logic is ready to make use of the chunk-format
write API. Each chunk write method is already in the correct prototype.
We only need to use the 'struct chunkfile' pointer and the correct API
calls.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In anticipation of combining the logic from the commit-graph and
multi-pack-index file formats, create a new chunk-format API. Use a
'struct chunkfile' pointer to keep track of data that has been
registered for writes. This struct is anonymous outside of
chunk-format.c to ensure no user attempts to interfere with the data.
The next change will use this API in commit-graph.c, but the general
approach is:
1. initialize the chunkfile with init_chunkfile(f).
2. add chunks in the intended writing order with add_chunk().
3. write any header information to the hashfile f.
4. write the chunkfile data using write_chunkfile().
5. free the chunkfile struct using free_chunkfile().
Helped-by: Taylor Blau <me@ttaylorr.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The error message given when a configuration variable that is
expected to have a boolean value has been improved.
* ak/config-bad-bool-error:
config: improve error message for boolean config
"git reflog expire --stale-fix" can be used to repair the reflog by
removing entries that refer to objects that have been pruned away,
but was not careful to tolerate missing objects.
* js/reflog-expire-stale-fix:
reflog expire --stale-fix: be generous about missing objects
When certain features (e.g. grafts) used in the repository are
incompatible with the use of the commit-graph, we used to silently
turned commit-graph off; we now tell the user what we are doing.
* js/commit-graph-warning:
commit-graph: when incompatible with graphs, indicate why
Test to make sure "git rev-parse one-thing one-thing" gives
the same thing twice (when one-thing is --since=X).
* ew/rev-parse-since-test:
t1500: ensure current --since= behavior remains
Avoid individual tests in t5411 from getting affected by each other
by forcing them to use separate output files during the test.
* jx/t5411-unique-filenames:
t5411: refactor check of refs using test_cmp_refs
t5411: use different out file to prevent overwriting
Fix "git fsck --name-objects" which apparently has not been used by
anybody who is motivated enough to report breakage.
* js/fsck-name-objects-fix:
fsck --name-objects: be more careful parsing generation numbers
t1450: robustify `remove_object()`
The .mailmap is documented to be read only from the root level of a
working tree, but a stray file in a bare repository also was read
by accident, which has been corrected.
* jk/mailmap-only-at-root:
mailmap: only look for .mailmap in work tree
"git grep --untracked" is meant to be "let's ALSO find in these
files on the filesystem" when looking for matches in the working
tree files, and does not make any sense if the primary search is
done against the index, or the tree objects. The "--cached" and
"--untracked" options have been marked as mutually incompatible.
* mt/grep-cached-untracked:
grep: error out if --untracked is used with --cached
"git mergetool" feeds three versions (base, local and remote) of
a conflicted path unmodified. The command learned to optionally
prepare these files with unconflicted parts already resolved.
* sh/mergetool-hideresolved:
mergetool: add per-tool support and overrides for the hideResolved flag
mergetool: break setup_tool out into separate initialization function
mergetool: add hideResolved configuration
