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reftable/system: provide thin wrapper for tempfile subsystem

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We use the tempfile subsystem to write temporary tables, but given that
we're in the process of converting the reftable library to become
standalone we cannot use this subsystem directly anymore. While we could
in theory convert the code to use mkstemp(3p) instead, we'd lose access
to our infrastructure that automatically prunes tempfiles via atexit(3p)
or signal handlers.

Provide a thin wrapper for the tempfile subsystem instead. Like this,
the compatibility shim is fully self-contained in "reftable/system.c".
Downstream users of the reftable library would have to implement their
own tempfile shims by replacing "system.c" with a custom version.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Patrick Steinhardt
2024-11-18 16:34:03 +01:00
committed by Junio C Hamano
parent 86b770b0bb
commit 01e49941d6
4 changed files with 114 additions and 35 deletions
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57
reftable/stack.c
View File

@ -16,7 +16,6 @@ https://developers.google.com/open-source/licenses/bsd
#include "reftable-record.h"
#include "reftable-merged.h"
#include "writer.h"
#include "tempfile.h"
static int stack_try_add(struct reftable_stack *st,
int (*write_table)(struct reftable_writer *wr,
@ -867,7 +866,7 @@ int reftable_addition_add(struct reftable_addition *add,
struct reftable_buf tab_file_name = REFTABLE_BUF_INIT;
struct reftable_buf next_name = REFTABLE_BUF_INIT;
struct reftable_writer *wr = NULL;
struct tempfile *tab_file = NULL;
struct reftable_tmpfile tab_file = REFTABLE_TMPFILE_INIT;
struct fd_writer writer = {
.opts = &add->stack->opts,
};
@ -887,20 +886,18 @@ int reftable_addition_add(struct reftable_addition *add,
if (err < 0)
goto done;
tab_file = mks_tempfile(temp_tab_file_name.buf);
if (!tab_file) {
err = REFTABLE_IO_ERROR;
err = tmpfile_from_pattern(&tab_file, temp_tab_file_name.buf);
if (err < 0)
goto done;
}
if (add->stack->opts.default_permissions) {
if (chmod(get_tempfile_path(tab_file),
if (chmod(tab_file.path,
add->stack->opts.default_permissions)) {
err = REFTABLE_IO_ERROR;
goto done;
}
}
writer.fd = get_tempfile_fd(tab_file);
writer.fd = tab_file.fd;
err = reftable_writer_new(&wr, fd_writer_write, fd_writer_flush,
&writer, &add->stack->opts);
if (err < 0)
@ -918,11 +915,9 @@ int reftable_addition_add(struct reftable_addition *add,
if (err < 0)
goto done;
err = close_tempfile_gently(tab_file);
if (err < 0) {
err = REFTABLE_IO_ERROR;
err = tmpfile_close(&tab_file);
if (err < 0)
goto done;
}
if (wr->min_update_index < add->next_update_index) {
err = REFTABLE_API_ERROR;
@ -945,11 +940,9 @@ int reftable_addition_add(struct reftable_addition *add,
On windows, this relies on rand() picking a unique destination name.
Maybe we should do retry loop as well?
*/
err = rename_tempfile(&tab_file, tab_file_name.buf);
if (err < 0) {
err = REFTABLE_IO_ERROR;
err = tmpfile_rename(&tab_file, tab_file_name.buf);
if (err < 0)
goto done;
}
REFTABLE_ALLOC_GROW(add->new_tables, add->new_tables_len + 1,
add->new_tables_cap);
@ -960,7 +953,7 @@ int reftable_addition_add(struct reftable_addition *add,
add->new_tables[add->new_tables_len++] = reftable_buf_detach(&next_name);
done:
delete_tempfile(&tab_file);
tmpfile_delete(&tab_file);
reftable_buf_release(&temp_tab_file_name);
reftable_buf_release(&tab_file_name);
reftable_buf_release(&next_name);
@ -980,7 +973,7 @@ uint64_t reftable_stack_next_update_index(struct reftable_stack *st)
static int stack_compact_locked(struct reftable_stack *st,
size_t first, size_t last,
struct reftable_log_expiry_config *config,
struct tempfile **tab_file_out)
struct reftable_tmpfile *tab_file_out)
{
struct reftable_buf next_name = REFTABLE_BUF_INIT;
struct reftable_buf tab_file_path = REFTABLE_BUF_INIT;
@ -988,7 +981,7 @@ static int stack_compact_locked(struct reftable_stack *st,
struct fd_writer writer= {
.opts = &st->opts,
};
struct tempfile *tab_file;
struct reftable_tmpfile tab_file = REFTABLE_TMPFILE_INIT;
int err = 0;
err = format_name(&next_name, reftable_reader_min_update_index(st->readers[first]),
@ -1004,19 +997,17 @@ static int stack_compact_locked(struct reftable_stack *st,
if (err < 0)
goto done;
tab_file = mks_tempfile(tab_file_path.buf);
if (!tab_file) {
err = REFTABLE_IO_ERROR;
err = tmpfile_from_pattern(&tab_file, tab_file_path.buf);
if (err < 0)
goto done;
}
if (st->opts.default_permissions &&
chmod(get_tempfile_path(tab_file), st->opts.default_permissions) < 0) {
chmod(tab_file.path, st->opts.default_permissions) < 0) {
err = REFTABLE_IO_ERROR;
goto done;
}
writer.fd = get_tempfile_fd(tab_file);
writer.fd = tab_file.fd;
err = reftable_writer_new(&wr, fd_writer_write, fd_writer_flush,
&writer, &st->opts);
if (err < 0)
@ -1030,15 +1021,15 @@ static int stack_compact_locked(struct reftable_stack *st,
if (err < 0)
goto done;
err = close_tempfile_gently(tab_file);
err = tmpfile_close(&tab_file);
if (err < 0)
goto done;
*tab_file_out = tab_file;
tab_file = NULL;
tab_file = REFTABLE_TMPFILE_INIT;
done:
delete_tempfile(&tab_file);
tmpfile_delete(&tab_file);
reftable_writer_free(wr);
reftable_buf_release(&next_name);
reftable_buf_release(&tab_file_path);
@ -1171,7 +1162,7 @@ static int stack_compact_range(struct reftable_stack *st,
struct reftable_buf table_name = REFTABLE_BUF_INIT;
struct lock_file tables_list_lock = LOCK_INIT;
struct lock_file *table_locks = NULL;
struct tempfile *new_table = NULL;
struct reftable_tmpfile new_table = REFTABLE_TMPFILE_INIT;
int is_empty_table = 0, err = 0;
size_t first_to_replace, last_to_replace;
size_t i, nlocks = 0;
@ -1439,11 +1430,9 @@ static int stack_compact_range(struct reftable_stack *st,
if (err < 0)
goto done;
err = rename_tempfile(&new_table, new_table_path.buf);
if (err < 0) {
err = REFTABLE_IO_ERROR;
err = tmpfile_rename(&new_table, new_table_path.buf);
if (err < 0)
goto done;
}
}
/*
@ -1515,7 +1504,7 @@ done:
rollback_lock_file(&table_locks[i]);
reftable_free(table_locks);
delete_tempfile(&new_table);
tmpfile_delete(&new_table);
reftable_buf_release(&new_table_name);
reftable_buf_release(&new_table_path);
reftable_buf_release(&tables_list_buf);