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1632 lines (1422 loc) · 40.5 KB
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Copy pathstack.c
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1632 lines (1422 loc) · 40.5 KB
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/*
Copyright 2020 Google LLC
Use of this source code is governed by a BSD-style
license that can be found in the LICENSE file or at
https://developers.google.com/open-source/licenses/bsd
*/
#include "stack.h"
#include "../write-or-die.h"
#include "system.h"
#include "constants.h"
#include "merged.h"
#include "reader.h"
#include "reftable-error.h"
#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,
void *arg),
void *arg);
static int stack_write_compact(struct reftable_stack *st,
struct reftable_writer *wr,
size_t first, size_t last,
struct reftable_log_expiry_config *config);
static void reftable_addition_close(struct reftable_addition *add);
static int reftable_stack_reload_maybe_reuse(struct reftable_stack *st,
int reuse_open);
static void stack_filename(struct strbuf *dest, struct reftable_stack *st,
const char *name)
{
strbuf_reset(dest);
strbuf_addstr(dest, st->reftable_dir);
strbuf_addstr(dest, "/");
strbuf_addstr(dest, name);
}
static ssize_t reftable_fd_write(void *arg, const void *data, size_t sz)
{
int *fdp = (int *)arg;
return write_in_full(*fdp, data, sz);
}
static int reftable_fd_flush(void *arg)
{
int *fdp = (int *)arg;
return fsync_component(FSYNC_COMPONENT_REFERENCE, *fdp);
}
int reftable_new_stack(struct reftable_stack **dest, const char *dir,
const struct reftable_write_options *_opts)
{
struct reftable_stack *p = reftable_calloc(1, sizeof(*p));
struct strbuf list_file_name = STRBUF_INIT;
struct reftable_write_options opts = {0};
int err = 0;
if (_opts)
opts = *_opts;
if (opts.hash_id == 0)
opts.hash_id = GIT_SHA1_FORMAT_ID;
*dest = NULL;
strbuf_reset(&list_file_name);
strbuf_addstr(&list_file_name, dir);
strbuf_addstr(&list_file_name, "/tables.list");
p->list_file = strbuf_detach(&list_file_name, NULL);
p->list_fd = -1;
p->reftable_dir = xstrdup(dir);
p->opts = opts;
err = reftable_stack_reload_maybe_reuse(p, 1);
if (err < 0) {
reftable_stack_destroy(p);
} else {
*dest = p;
}
return err;
}
static int fd_read_lines(int fd, char ***namesp)
{
off_t size = lseek(fd, 0, SEEK_END);
char *buf = NULL;
int err = 0;
if (size < 0) {
err = REFTABLE_IO_ERROR;
goto done;
}
err = lseek(fd, 0, SEEK_SET);
if (err < 0) {
err = REFTABLE_IO_ERROR;
goto done;
}
REFTABLE_ALLOC_ARRAY(buf, size + 1);
if (read_in_full(fd, buf, size) != size) {
err = REFTABLE_IO_ERROR;
goto done;
}
buf[size] = 0;
parse_names(buf, size, namesp);
done:
reftable_free(buf);
return err;
}
int read_lines(const char *filename, char ***namesp)
{
int fd = open(filename, O_RDONLY);
int err = 0;
if (fd < 0) {
if (errno == ENOENT) {
REFTABLE_CALLOC_ARRAY(*namesp, 1);
return 0;
}
return REFTABLE_IO_ERROR;
}
err = fd_read_lines(fd, namesp);
close(fd);
return err;
}
void reftable_stack_init_ref_iterator(struct reftable_stack *st,
struct reftable_iterator *it)
{
merged_table_init_iter(reftable_stack_merged_table(st),
it, BLOCK_TYPE_REF);
}
void reftable_stack_init_log_iterator(struct reftable_stack *st,
struct reftable_iterator *it)
{
merged_table_init_iter(reftable_stack_merged_table(st),
it, BLOCK_TYPE_LOG);
}
struct reftable_merged_table *
reftable_stack_merged_table(struct reftable_stack *st)
{
return st->merged;
}
static int has_name(char **names, const char *name)
{
while (*names) {
if (!strcmp(*names, name))
return 1;
names++;
}
return 0;
}
/* Close and free the stack */
void reftable_stack_destroy(struct reftable_stack *st)
{
char **names = NULL;
int err = 0;
if (st->merged) {
reftable_merged_table_free(st->merged);
st->merged = NULL;
}
err = read_lines(st->list_file, &names);
if (err < 0) {
FREE_AND_NULL(names);
}
if (st->readers) {
int i = 0;
struct strbuf filename = STRBUF_INIT;
for (i = 0; i < st->readers_len; i++) {
const char *name = reader_name(st->readers[i]);
strbuf_reset(&filename);
if (names && !has_name(names, name)) {
stack_filename(&filename, st, name);
}
reftable_reader_decref(st->readers[i]);
if (filename.len) {
/* On Windows, can only unlink after closing. */
unlink(filename.buf);
}
}
strbuf_release(&filename);
st->readers_len = 0;
FREE_AND_NULL(st->readers);
}
if (st->list_fd >= 0) {
close(st->list_fd);
st->list_fd = -1;
}
FREE_AND_NULL(st->list_file);
FREE_AND_NULL(st->reftable_dir);
reftable_free(st);
free_names(names);
}
static struct reftable_reader **stack_copy_readers(struct reftable_stack *st,
int cur_len)
{
struct reftable_reader **cur = reftable_calloc(cur_len, sizeof(*cur));
int i = 0;
for (i = 0; i < cur_len; i++) {
cur[i] = st->readers[i];
}
return cur;
}
static int reftable_stack_reload_once(struct reftable_stack *st,
const char **names,
int reuse_open)
{
size_t cur_len = !st->merged ? 0 : st->merged->readers_len;
struct reftable_reader **cur = stack_copy_readers(st, cur_len);
struct reftable_reader **reused = NULL;
size_t reused_len = 0, reused_alloc = 0;
size_t names_len = names_length(names);
struct reftable_reader **new_readers =
reftable_calloc(names_len, sizeof(*new_readers));
size_t new_readers_len = 0;
struct reftable_merged_table *new_merged = NULL;
struct strbuf table_path = STRBUF_INIT;
int err = 0;
size_t i;
while (*names) {
struct reftable_reader *rd = NULL;
const char *name = *names++;
/* this is linear; we assume compaction keeps the number of
tables under control so this is not quadratic. */
for (i = 0; reuse_open && i < cur_len; i++) {
if (cur[i] && 0 == strcmp(cur[i]->name, name)) {
rd = cur[i];
cur[i] = NULL;
/*
* When reloading the stack fails, we end up
* releasing all new readers. This also
* includes the reused readers, even though
* they are still in used by the old stack. We
* thus need to keep them alive here, which we
* do by bumping their refcount.
*/
REFTABLE_ALLOC_GROW(reused, reused_len + 1, reused_alloc);
reused[reused_len++] = rd;
reftable_reader_incref(rd);
break;
}
}
if (!rd) {
struct reftable_block_source src = { NULL };
stack_filename(&table_path, st, name);
err = reftable_block_source_from_file(&src,
table_path.buf);
if (err < 0)
goto done;
err = reftable_reader_new(&rd, &src, name);
if (err < 0)
goto done;
}
new_readers[new_readers_len] = rd;
new_readers_len++;
}
/* success! */
err = reftable_merged_table_new(&new_merged, new_readers,
new_readers_len, st->opts.hash_id);
if (err < 0)
goto done;
/*
* Close the old, non-reused readers and proactively try to unlink
* them. This is done for systems like Windows, where the underlying
* file of such an open reader wouldn't have been possible to be
* unlinked by the compacting process.
*/
for (i = 0; i < cur_len; i++) {
if (cur[i]) {
const char *name = reader_name(cur[i]);
stack_filename(&table_path, st, name);
reftable_reader_decref(cur[i]);
unlink(table_path.buf);
}
}
/* Update the stack to point to the new tables. */
if (st->merged)
reftable_merged_table_free(st->merged);
new_merged->suppress_deletions = 1;
st->merged = new_merged;
if (st->readers)
reftable_free(st->readers);
st->readers = new_readers;
st->readers_len = new_readers_len;
new_readers = NULL;
new_readers_len = 0;
/*
* Decrement the refcount of reused readers again. This only needs to
* happen on the successful case, because on the unsuccessful one we
* decrement their refcount via `new_readers`.
*/
for (i = 0; i < reused_len; i++)
reftable_reader_decref(reused[i]);
done:
for (i = 0; i < new_readers_len; i++)
reftable_reader_decref(new_readers[i]);
reftable_free(new_readers);
reftable_free(reused);
reftable_free(cur);
strbuf_release(&table_path);
return err;
}
/* return negative if a before b. */
static int tv_cmp(struct timeval *a, struct timeval *b)
{
time_t diff = a->tv_sec - b->tv_sec;
int udiff = a->tv_usec - b->tv_usec;
if (diff != 0)
return diff;
return udiff;
}
static int reftable_stack_reload_maybe_reuse(struct reftable_stack *st,
int reuse_open)
{
char **names = NULL, **names_after = NULL;
struct timeval deadline;
int64_t delay = 0;
int tries = 0, err;
int fd = -1;
err = gettimeofday(&deadline, NULL);
if (err < 0)
goto out;
deadline.tv_sec += 3;
while (1) {
struct timeval now;
err = gettimeofday(&now, NULL);
if (err < 0)
goto out;
/*
* Only look at deadlines after the first few times. This
* simplifies debugging in GDB.
*/
tries++;
if (tries > 3 && tv_cmp(&now, &deadline) >= 0)
goto out;
fd = open(st->list_file, O_RDONLY);
if (fd < 0) {
if (errno != ENOENT) {
err = REFTABLE_IO_ERROR;
goto out;
}
REFTABLE_CALLOC_ARRAY(names, 1);
} else {
err = fd_read_lines(fd, &names);
if (err < 0)
goto out;
}
err = reftable_stack_reload_once(st, (const char **) names, reuse_open);
if (!err)
break;
if (err != REFTABLE_NOT_EXIST_ERROR)
goto out;
/*
* REFTABLE_NOT_EXIST_ERROR can be caused by a concurrent
* writer. Check if there was one by checking if the name list
* changed.
*/
err = read_lines(st->list_file, &names_after);
if (err < 0)
goto out;
if (names_equal((const char **) names_after,
(const char **) names)) {
err = REFTABLE_NOT_EXIST_ERROR;
goto out;
}
free_names(names);
names = NULL;
free_names(names_after);
names_after = NULL;
close(fd);
fd = -1;
delay = delay + (delay * rand()) / RAND_MAX + 1;
sleep_millisec(delay);
}
out:
/*
* Invalidate the stat cache. It is sufficient to only close the file
* descriptor and keep the cached stat info because we never use the
* latter when the former is negative.
*/
if (st->list_fd >= 0) {
close(st->list_fd);
st->list_fd = -1;
}
/*
* Cache stat information in case it provides a useful signal to us.
* According to POSIX, "The st_ino and st_dev fields taken together
* uniquely identify the file within the system." That being said,
* Windows is not POSIX compliant and we do not have these fields
* available. So the information we have there is insufficient to
* determine whether two file descriptors point to the same file.
*
* While we could fall back to using other signals like the file's
* mtime, those are not sufficient to avoid races. We thus refrain from
* using the stat cache on such systems and fall back to the secondary
* caching mechanism, which is to check whether contents of the file
* have changed.
*
* On other systems which are POSIX compliant we must keep the file
* descriptor open. This is to avoid a race condition where two
* processes access the reftable stack at the same point in time:
*
* 1. A reads the reftable stack and caches its stat info.
*
* 2. B updates the stack, appending a new table to "tables.list".
* This will both use a new inode and result in a different file
* size, thus invalidating A's cache in theory.
*
* 3. B decides to auto-compact the stack and merges two tables. The
* file size now matches what A has cached again. Furthermore, the
* filesystem may decide to recycle the inode number of the file
* we have replaced in (2) because it is not in use anymore.
*
* 4. A reloads the reftable stack. Neither the inode number nor the
* file size changed. If the timestamps did not change either then
* we think the cached copy of our stack is up-to-date.
*
* By keeping the file descriptor open the inode number cannot be
* recycled, mitigating the race.
*/
if (!err && fd >= 0 && !fstat(fd, &st->list_st) &&
st->list_st.st_dev && st->list_st.st_ino) {
st->list_fd = fd;
fd = -1;
}
if (fd >= 0)
close(fd);
free_names(names);
free_names(names_after);
return err;
}
/* -1 = error
0 = up to date
1 = changed. */
static int stack_uptodate(struct reftable_stack *st)
{
char **names = NULL;
int err;
int i = 0;
/*
* When we have cached stat information available then we use it to
* verify whether the file has been rewritten.
*
* Note that we explicitly do not want to use `stat_validity_check()`
* and friends here because they may end up not comparing the `st_dev`
* and `st_ino` fields. These functions thus cannot guarantee that we
* indeed still have the same file.
*/
if (st->list_fd >= 0) {
struct stat list_st;
if (stat(st->list_file, &list_st) < 0) {
/*
* It's fine for "tables.list" to not exist. In that
* case, we have to refresh when the loaded stack has
* any readers.
*/
if (errno == ENOENT)
return !!st->readers_len;
return REFTABLE_IO_ERROR;
}
/*
* When "tables.list" refers to the same file we can assume
* that it didn't change. This is because we always use
* rename(3P) to update the file and never write to it
* directly.
*/
if (st->list_st.st_dev == list_st.st_dev &&
st->list_st.st_ino == list_st.st_ino)
return 0;
}
err = read_lines(st->list_file, &names);
if (err < 0)
return err;
for (i = 0; i < st->readers_len; i++) {
if (!names[i]) {
err = 1;
goto done;
}
if (strcmp(st->readers[i]->name, names[i])) {
err = 1;
goto done;
}
}
if (names[st->merged->readers_len]) {
err = 1;
goto done;
}
done:
free_names(names);
return err;
}
int reftable_stack_reload(struct reftable_stack *st)
{
int err = stack_uptodate(st);
if (err > 0)
return reftable_stack_reload_maybe_reuse(st, 1);
return err;
}
int reftable_stack_add(struct reftable_stack *st,
int (*write)(struct reftable_writer *wr, void *arg),
void *arg)
{
int err = stack_try_add(st, write, arg);
if (err < 0) {
if (err == REFTABLE_OUTDATED_ERROR) {
/* Ignore error return, we want to propagate
REFTABLE_OUTDATED_ERROR.
*/
reftable_stack_reload(st);
}
return err;
}
return 0;
}
static void format_name(struct strbuf *dest, uint64_t min, uint64_t max)
{
char buf[100];
uint32_t rnd = (uint32_t)git_rand();
snprintf(buf, sizeof(buf), "0x%012" PRIx64 "-0x%012" PRIx64 "-%08x",
min, max, rnd);
strbuf_reset(dest);
strbuf_addstr(dest, buf);
}
struct reftable_addition {
struct lock_file tables_list_lock;
struct reftable_stack *stack;
char **new_tables;
size_t new_tables_len, new_tables_cap;
uint64_t next_update_index;
};
#define REFTABLE_ADDITION_INIT {0}
static int reftable_stack_init_addition(struct reftable_addition *add,
struct reftable_stack *st,
unsigned int flags)
{
struct strbuf lock_file_name = STRBUF_INIT;
int err;
add->stack = st;
err = hold_lock_file_for_update_timeout(&add->tables_list_lock,
st->list_file,
LOCK_NO_DEREF,
st->opts.lock_timeout_ms);
if (err < 0) {
if (errno == EEXIST) {
err = REFTABLE_LOCK_ERROR;
} else {
err = REFTABLE_IO_ERROR;
}
goto done;
}
if (st->opts.default_permissions) {
if (chmod(get_lock_file_path(&add->tables_list_lock),
st->opts.default_permissions) < 0) {
err = REFTABLE_IO_ERROR;
goto done;
}
}
err = stack_uptodate(st);
if (err < 0)
goto done;
if (err > 0 && flags & REFTABLE_STACK_NEW_ADDITION_RELOAD) {
err = reftable_stack_reload_maybe_reuse(add->stack, 1);
if (err)
goto done;
}
if (err > 0) {
err = REFTABLE_OUTDATED_ERROR;
goto done;
}
add->next_update_index = reftable_stack_next_update_index(st);
done:
if (err)
reftable_addition_close(add);
strbuf_release(&lock_file_name);
return err;
}
static void reftable_addition_close(struct reftable_addition *add)
{
struct strbuf nm = STRBUF_INIT;
size_t i;
for (i = 0; i < add->new_tables_len; i++) {
stack_filename(&nm, add->stack, add->new_tables[i]);
unlink(nm.buf);
reftable_free(add->new_tables[i]);
add->new_tables[i] = NULL;
}
reftable_free(add->new_tables);
add->new_tables = NULL;
add->new_tables_len = 0;
add->new_tables_cap = 0;
rollback_lock_file(&add->tables_list_lock);
strbuf_release(&nm);
}
void reftable_addition_destroy(struct reftable_addition *add)
{
if (!add) {
return;
}
reftable_addition_close(add);
reftable_free(add);
}
int reftable_addition_commit(struct reftable_addition *add)
{
struct strbuf table_list = STRBUF_INIT;
int lock_file_fd = get_lock_file_fd(&add->tables_list_lock);
int err = 0;
size_t i;
if (add->new_tables_len == 0)
goto done;
for (i = 0; i < add->stack->merged->readers_len; i++) {
strbuf_addstr(&table_list, add->stack->readers[i]->name);
strbuf_addstr(&table_list, "\n");
}
for (i = 0; i < add->new_tables_len; i++) {
strbuf_addstr(&table_list, add->new_tables[i]);
strbuf_addstr(&table_list, "\n");
}
err = write_in_full(lock_file_fd, table_list.buf, table_list.len);
strbuf_release(&table_list);
if (err < 0) {
err = REFTABLE_IO_ERROR;
goto done;
}
err = fsync_component(FSYNC_COMPONENT_REFERENCE, lock_file_fd);
if (err < 0) {
err = REFTABLE_IO_ERROR;
goto done;
}
err = commit_lock_file(&add->tables_list_lock);
if (err < 0) {
err = REFTABLE_IO_ERROR;
goto done;
}
/* success, no more state to clean up. */
for (i = 0; i < add->new_tables_len; i++)
reftable_free(add->new_tables[i]);
reftable_free(add->new_tables);
add->new_tables = NULL;
add->new_tables_len = 0;
add->new_tables_cap = 0;
err = reftable_stack_reload_maybe_reuse(add->stack, 1);
if (err)
goto done;
if (!add->stack->opts.disable_auto_compact) {
/*
* Auto-compact the stack to keep the number of tables in
* control. It is possible that a concurrent writer is already
* trying to compact parts of the stack, which would lead to a
* `REFTABLE_LOCK_ERROR` because parts of the stack are locked
* already. This is a benign error though, so we ignore it.
*/
err = reftable_stack_auto_compact(add->stack);
if (err < 0 && err != REFTABLE_LOCK_ERROR)
goto done;
err = 0;
}
done:
reftable_addition_close(add);
return err;
}
int reftable_stack_new_addition(struct reftable_addition **dest,
struct reftable_stack *st,
unsigned int flags)
{
int err = 0;
struct reftable_addition empty = REFTABLE_ADDITION_INIT;
REFTABLE_CALLOC_ARRAY(*dest, 1);
**dest = empty;
err = reftable_stack_init_addition(*dest, st, flags);
if (err) {
reftable_free(*dest);
*dest = NULL;
}
return err;
}
static int stack_try_add(struct reftable_stack *st,
int (*write_table)(struct reftable_writer *wr,
void *arg),
void *arg)
{
struct reftable_addition add = REFTABLE_ADDITION_INIT;
int err = reftable_stack_init_addition(&add, st, 0);
if (err < 0)
goto done;
err = reftable_addition_add(&add, write_table, arg);
if (err < 0)
goto done;
err = reftable_addition_commit(&add);
done:
reftable_addition_close(&add);
return err;
}
int reftable_addition_add(struct reftable_addition *add,
int (*write_table)(struct reftable_writer *wr,
void *arg),
void *arg)
{
struct strbuf temp_tab_file_name = STRBUF_INIT;
struct strbuf tab_file_name = STRBUF_INIT;
struct strbuf next_name = STRBUF_INIT;
struct reftable_writer *wr = NULL;
struct tempfile *tab_file = NULL;
int err = 0;
int tab_fd;
strbuf_reset(&next_name);
format_name(&next_name, add->next_update_index, add->next_update_index);
stack_filename(&temp_tab_file_name, add->stack, next_name.buf);
strbuf_addstr(&temp_tab_file_name, ".temp.XXXXXX");
tab_file = mks_tempfile(temp_tab_file_name.buf);
if (!tab_file) {
err = REFTABLE_IO_ERROR;
goto done;
}
if (add->stack->opts.default_permissions) {
if (chmod(get_tempfile_path(tab_file),
add->stack->opts.default_permissions)) {
err = REFTABLE_IO_ERROR;
goto done;
}
}
tab_fd = get_tempfile_fd(tab_file);
wr = reftable_new_writer(reftable_fd_write, reftable_fd_flush, &tab_fd,
&add->stack->opts);
err = write_table(wr, arg);
if (err < 0)
goto done;
err = reftable_writer_close(wr);
if (err == REFTABLE_EMPTY_TABLE_ERROR) {
err = 0;
goto done;
}
if (err < 0)
goto done;
err = close_tempfile_gently(tab_file);
if (err < 0) {
err = REFTABLE_IO_ERROR;
goto done;
}
if (wr->min_update_index < add->next_update_index) {
err = REFTABLE_API_ERROR;
goto done;
}
format_name(&next_name, wr->min_update_index, wr->max_update_index);
strbuf_addstr(&next_name, ".ref");
stack_filename(&tab_file_name, add->stack, next_name.buf);
/*
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;
goto done;
}
REFTABLE_ALLOC_GROW(add->new_tables, add->new_tables_len + 1,
add->new_tables_cap);
add->new_tables[add->new_tables_len++] = strbuf_detach(&next_name, NULL);
done:
delete_tempfile(&tab_file);
strbuf_release(&temp_tab_file_name);
strbuf_release(&tab_file_name);
strbuf_release(&next_name);
reftable_writer_free(wr);
return err;
}
uint64_t reftable_stack_next_update_index(struct reftable_stack *st)
{
int sz = st->merged->readers_len;
if (sz > 0)
return reftable_reader_max_update_index(st->readers[sz - 1]) +
1;
return 1;
}
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 strbuf next_name = STRBUF_INIT;
struct strbuf tab_file_path = STRBUF_INIT;
struct reftable_writer *wr = NULL;
struct tempfile *tab_file;
int tab_fd, err = 0;
format_name(&next_name,
reftable_reader_min_update_index(st->readers[first]),
reftable_reader_max_update_index(st->readers[last]));
stack_filename(&tab_file_path, st, next_name.buf);
strbuf_addstr(&tab_file_path, ".temp.XXXXXX");
tab_file = mks_tempfile(tab_file_path.buf);
if (!tab_file) {
err = REFTABLE_IO_ERROR;
goto done;
}
tab_fd = get_tempfile_fd(tab_file);
if (st->opts.default_permissions &&
chmod(get_tempfile_path(tab_file), st->opts.default_permissions) < 0) {
err = REFTABLE_IO_ERROR;
goto done;
}
wr = reftable_new_writer(reftable_fd_write, reftable_fd_flush,
&tab_fd, &st->opts);
err = stack_write_compact(st, wr, first, last, config);
if (err < 0)
goto done;
err = reftable_writer_close(wr);
if (err < 0)
goto done;
err = close_tempfile_gently(tab_file);
if (err < 0)
goto done;
*tab_file_out = tab_file;
tab_file = NULL;
done:
delete_tempfile(&tab_file);
reftable_writer_free(wr);
strbuf_release(&next_name);
strbuf_release(&tab_file_path);
return err;
}
static int stack_write_compact(struct reftable_stack *st,
struct reftable_writer *wr,
size_t first, size_t last,
struct reftable_log_expiry_config *config)
{
struct reftable_merged_table *mt = NULL;
struct reftable_iterator it = { NULL };
struct reftable_ref_record ref = { NULL };
struct reftable_log_record log = { NULL };
size_t subtabs_len = last - first + 1;
uint64_t entries = 0;
int err = 0;
for (size_t i = first; i <= last; i++)
st->stats.bytes += st->readers[i]->size;
reftable_writer_set_limits(wr, st->readers[first]->min_update_index,
st->readers[last]->max_update_index);
err = reftable_merged_table_new(&mt, st->readers + first, subtabs_len,
st->opts.hash_id);
if (err < 0)
goto done;
merged_table_init_iter(mt, &it, BLOCK_TYPE_REF);
err = reftable_iterator_seek_ref(&it, "");
if (err < 0)
goto done;
while (1) {
err = reftable_iterator_next_ref(&it, &ref);
if (err > 0) {
err = 0;
break;
}
if (err < 0)
goto done;
if (first == 0 && reftable_ref_record_is_deletion(&ref)) {
continue;
}
err = reftable_writer_add_ref(wr, &ref);
if (err < 0)
goto done;
entries++;
}
reftable_iterator_destroy(&it);
merged_table_init_iter(mt, &it, BLOCK_TYPE_LOG);
err = reftable_iterator_seek_log(&it, "");
if (err < 0)
goto done;
while (1) {
err = reftable_iterator_next_log(&it, &log);
if (err > 0) {
err = 0;
break;
}
if (err < 0)
goto done;
if (first == 0 && reftable_log_record_is_deletion(&log)) {
continue;
}
if (config && config->min_update_index > 0 &&
log.update_index < config->min_update_index) {
continue;
}
if (config && config->time > 0 &&
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