git/reftable/blocksource.c, branch main

reftable/system: add abstraction to mmap files

2026-04-02T17:45:44Z

In our codebase we have a couple of wrappers around mmap(3p) that allow us to reimplement the syscall on platforms that don't have it natively, like for example Windows. Other projects that embed the reftable library may have a different infra though to hook up mmap wrappers, but these are currently hard to integrate. Provide the infrastructure to let projects easily define the mmap interface with a custom struct and custom functions. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

reftable/block: rename `block` to `block_data`

2025-04-07T21:53:10Z

The `reftable_block` structure associates a byte slice with a block source. As such it only holds the data of a reftable block without actually encoding any of the details for how to access that data. Rename the structure to instead be called `reftable_block_data`. Besides clarifying that this really only holds data, it also allows us to rename the `reftable_block_reader` to `reftable_block` in the next commit, as this is the structure that actually encapsulates access to the reftable blocks. Rename the `struct reftable_block_reader::block` member accordingly. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

reftable/blocksource: consolidate code into a single file

2025-04-07T21:53:09Z

The code that implements block sources is distributed across a couple of files. Consolidate all of it into "reftable/blocksource.c" and its accompanying header so that it is easier to locate and more self contained. While at it, rename some of the functions to have properly scoped names. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

reftable: fix formatting of the license header

2025-04-07T21:53:09Z

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 Signed-off-by: Junio C Hamano

reftable/basics: introduce `REFTABLE_UNUSED` annotation

2025-02-18T18:55:38Z

Introduce the `REFTABLE_UNUSED` annotation and replace all existing users of `UNUSED` in the reftable library to use the new macro instead. Note that we unconditionally define `MAYBE_UNUSED` in the exact same way, so doing so unconditionally for `REFTABLE_UNUSED` should be fine, too. Suggested-by: Toon Claes Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

reftable/blocksource: stop using `xmmap()`

2025-02-18T18:55:35Z

We use `xmmap()` to map reftables into memory. This function has two problems: - It causes us to die in case the mmap fails. - It ties us to the Git codebase. Refactor the code to use mmap(3p) instead with manual error checking. Note that this function may not be the system-provided mmap(3p), but may point to our `git_mmap()` wrapper that emulates the syscall on systems that do not have mmap(3p) available. Fix `reftable_block_source_from_file()` to properly bubble up the error code in case the map(3p) call fails. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

reftable/blocksource: adjust `read_block()` to return `ssize_t`

2025-01-21T22:20:30Z

The `block_source_read_block()` function and its implementations return an integer as a result that reflects either the number of bytes read, or an error. As such its return type, a signed integer, isn't wrong, but it doesn't give the reader a good hint what it actually returns. Refactor the function to return an `ssize_t` instead, which is typical for functions similar to read(3p) and should thus give readers a better signal what they can expect as a result. Adjust callers to better handle the returned value to avoid warnings with -Wsign-compare. One of these callers is `reader_get_block()`, whose return value is only ever used by its callers to figure out whether or not the read was successful. So instead of bubbling up the `ssize_t` there, too, we adapt it to only indicate success or errors. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

reftable/blocksource: adapt interface name

2024-10-17T20:59:56Z

Adapt the name of the `strbuf` block source to no longer relate to this interface, but instead to the `reftable_buf` interface. Signed-off-by: Patrick Steinhardt Signed-off-by: Taylor Blau

reftable: convert from `strbuf` to `reftable_buf`

2024-10-17T20:59:56Z

Convert the reftable library to use the `reftable_buf` interface instead of the `strbuf` interface. This is mostly a mechanical change via sed(1) with some manual fixes where functions for `strbuf` and `reftable_buf` differ. The converted code does not yet handle allocation failures. This will be handled in subsequent commits. Signed-off-by: Patrick Steinhardt Signed-off-by: Taylor Blau

reftable/blocksource: handle allocation failures

2024-10-02T14:53:54Z

Handle allocation failures in the blocksource code. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano