The `struct reftable_reader` subsystem encapsulates a table that has
been read from the disk. As such, the current name of that structure is
somewhat hard to understand as it only talks about the fact that we read
something from disk, without really giving an indicator _what_ that is.
Furthermore, this naming schema doesn't really fit well into how the
other structures are named: `reftable_merged_table`, `reftable_stack`,
`reftable_block` and `reftable_record` are all named after what they
encapsulate.
Rename the subsystem to `reftable_table`, which directly gives a hint
that the data structure is about handling the individual tables part of
the stack.
While this change results in a lot of churn, it prepares for us exposing
the APIs to third-party callers now that the reftable library is a
standalone library that can be linked against by other projects.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The license headers used across the reftable library doesn't follow our
typical coding style for multi-line comments. Fix it.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We include "hash.h" in "reftable/system.h" such that we can use hash
format IDs as well as the raw size of SHA1 and SHA256. As we are in the
process of converting the reftable library to become standalone we of
course cannot rely on those constants anymore.
Introduce a new `enum reftable_hash` to replace internal uses of the
hash format IDs and new constants that replace internal uses of the hash
size. Adapt the reftable backend to set up the correct hash function.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Handle allocation failures in `merged_table_init_iter()`. While at it,
merge `merged_iter_init()` into the function. It only has a single
caller and merging them makes it easier to handle allocation failures
consistently.
This change also requires us to adapt `reftable_stack_init_*_iterator()`
to bubble up the new error codes of `merged_table_iter_init()`. Adapt
callsites accordingly.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `reftable_table` interface provides a generic infrastructure that
can abstract away whether the underlying table is a single table, or a
merged table. This abstraction can make it rather hard to reason about
the code. We didn't ever use it to implement the reftable backend, and
with the preceding patches in this patch series we in fact don't use it
at all anymore. Furthermore, it became somewhat useless with the recent
refactorings that made it possible to seek reftable iterators multiple
times, as these now provide generic access to tables for us. The
interface is thus redundant and only brings unnecessary complexity with
it.
Remove the `struct reftable_table` interface and its associated
functions.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The merged table provides access to a reftable stack by merging the
contents of those tables into a virtual table. These subtables are being
tracked via `struct reftable_table`, which is a generic interface for
accessing either a single reftable or a merged reftable. So in theory,
it would be possible for the merged table to merge together other merged
tables.
This is somewhat nonsensical though: we only ever set up a merged table
over normal reftables, and there is no reason to do otherwise. This
generic interface thus makes the code way harder to follow and reason
about than really necessary. The abstraction layer may also have an
impact on performance, even though the extra set of vtable function
calls probably doesn't really matter.
Refactor the merged tables to use a `struct reftable_reader` for each of
the subtables instead, which gives us direct access to the underlying
tables. Adjust names accordingly.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Rename `reftable_new_merged_table()` to `reftable_merged_table_new()`
such that the name matches our coding style.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We do not expose any functions via our public headers that would allow a
caller to initialize a reftable iterator from a merged table. Instead,
they are expected to go via the generic `reftable_table` interface,
which is somewhat roundabout.
Implement two new functions to initialize iterators for ref and log
records to plug this gap.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Refactor the interfaces exposed by `struct reftable_merged_table` and
`struct merged_iter` such that they support iterator reuse. This is done
by separating initialization of the iterator and seeking on it.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
While the stack length is already stored as `size_t`, we frequently use
`int`s to refer to those stacks throughout the reftable library. Convert
those cases to use `size_t` instead to make things consistent.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This adds an abstract, read-only interface to the ref database.
This primitive is used to construct the read view of the ref database
(the read view is constructed by merging several *.ref files). It also
provides the mechanism to provide a unified view of the refs in the main
repository and the per-worktree refs.
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Patrick Steinhardt