summaryrefslogtreecommitdiff
path: root/reftable/stack.c
diff options
context:
space:
mode:
Diffstat (limited to 'reftable/stack.c')
-rw-r--r--reftable/stack.c1396
1 files changed, 1396 insertions, 0 deletions
diff --git a/reftable/stack.c b/reftable/stack.c
new file mode 100644
index 0000000000..df5021ebf0
--- /dev/null
+++ b/reftable/stack.c
@@ -0,0 +1,1396 @@
+/*
+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 "system.h"
+#include "merged.h"
+#include "reader.h"
+#include "refname.h"
+#include "reftable-error.h"
+#include "reftable-record.h"
+#include "reftable-merged.h"
+#include "writer.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, int first, int last,
+ struct reftable_log_expiry_config *config);
+static int stack_check_addition(struct reftable_stack *st,
+ const char *new_tab_name);
+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(*fdp, data, sz);
+}
+
+int reftable_new_stack(struct reftable_stack **dest, const char *dir,
+ struct reftable_write_options config)
+{
+ struct reftable_stack *p =
+ reftable_calloc(sizeof(struct reftable_stack));
+ struct strbuf list_file_name = STRBUF_INIT;
+ int err = 0;
+
+ if (config.hash_id == 0) {
+ config.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->reftable_dir = xstrdup(dir);
+ p->config = config;
+
+ 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;
+ }
+
+ buf = reftable_malloc(size + 1);
+ if (read(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) {
+ *namesp = reftable_calloc(sizeof(char *));
+ return 0;
+ }
+
+ return REFTABLE_IO_ERROR;
+ }
+ err = fd_read_lines(fd, namesp);
+ close(fd);
+ return err;
+}
+
+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_free(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);
+ }
+ 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(sizeof(struct reftable_reader *) * cur_len);
+ 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, char **names,
+ int reuse_open)
+{
+ int cur_len = !st->merged ? 0 : st->merged->stack_len;
+ struct reftable_reader **cur = stack_copy_readers(st, cur_len);
+ int err = 0;
+ int names_len = names_length(names);
+ struct reftable_reader **new_readers =
+ reftable_calloc(sizeof(struct reftable_reader *) * names_len);
+ struct reftable_table *new_tables =
+ reftable_calloc(sizeof(struct reftable_table) * names_len);
+ int new_readers_len = 0;
+ struct reftable_merged_table *new_merged = NULL;
+ int i;
+
+ while (*names) {
+ struct reftable_reader *rd = NULL;
+ char *name = *names++;
+
+ /* this is linear; we assume compaction keeps the number of
+ tables under control so this is not quadratic. */
+ int j = 0;
+ for (j = 0; reuse_open && j < cur_len; j++) {
+ if (cur[j] && 0 == strcmp(cur[j]->name, name)) {
+ rd = cur[j];
+ cur[j] = NULL;
+ break;
+ }
+ }
+
+ if (!rd) {
+ struct reftable_block_source src = { NULL };
+ struct strbuf table_path = STRBUF_INIT;
+ stack_filename(&table_path, st, name);
+
+ err = reftable_block_source_from_file(&src,
+ table_path.buf);
+ strbuf_release(&table_path);
+
+ if (err < 0)
+ goto done;
+
+ err = reftable_new_reader(&rd, &src, name);
+ if (err < 0)
+ goto done;
+ }
+
+ new_readers[new_readers_len] = rd;
+ reftable_table_from_reader(&new_tables[new_readers_len], rd);
+ new_readers_len++;
+ }
+
+ /* success! */
+ err = reftable_new_merged_table(&new_merged, new_tables,
+ new_readers_len, st->config.hash_id);
+ if (err < 0)
+ goto done;
+
+ new_tables = NULL;
+ st->readers_len = new_readers_len;
+ if (st->merged) {
+ merged_table_release(st->merged);
+ reftable_merged_table_free(st->merged);
+ }
+ if (st->readers) {
+ reftable_free(st->readers);
+ }
+ st->readers = new_readers;
+ new_readers = NULL;
+ new_readers_len = 0;
+
+ new_merged->suppress_deletions = 1;
+ st->merged = new_merged;
+ for (i = 0; i < cur_len; i++) {
+ if (cur[i]) {
+ const char *name = reader_name(cur[i]);
+ struct strbuf filename = STRBUF_INIT;
+ stack_filename(&filename, st, name);
+
+ reader_close(cur[i]);
+ reftable_reader_free(cur[i]);
+
+ /* On Windows, can only unlink after closing. */
+ unlink(filename.buf);
+
+ strbuf_release(&filename);
+ }
+ }
+
+done:
+ for (i = 0; i < new_readers_len; i++) {
+ reader_close(new_readers[i]);
+ reftable_reader_free(new_readers[i]);
+ }
+ reftable_free(new_readers);
+ reftable_free(new_tables);
+ reftable_free(cur);
+ 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)
+{
+ struct timeval deadline = { 0 };
+ int err = gettimeofday(&deadline, NULL);
+ int64_t delay = 0;
+ int tries = 0;
+ if (err < 0)
+ return err;
+
+ deadline.tv_sec += 3;
+ while (1) {
+ char **names = NULL;
+ char **names_after = NULL;
+ struct timeval now = { 0 };
+ int err = gettimeofday(&now, NULL);
+ int err2 = 0;
+ if (err < 0) {
+ return err;
+ }
+
+ /* Only look at deadlines after the first few times. This
+ simplifies debugging in GDB */
+ tries++;
+ if (tries > 3 && tv_cmp(&now, &deadline) >= 0) {
+ break;
+ }
+
+ err = read_lines(st->list_file, &names);
+ if (err < 0) {
+ free_names(names);
+ return err;
+ }
+ err = reftable_stack_reload_once(st, names, reuse_open);
+ if (err == 0) {
+ free_names(names);
+ break;
+ }
+ if (err != REFTABLE_NOT_EXIST_ERROR) {
+ free_names(names);
+ return err;
+ }
+
+ /* err == REFTABLE_NOT_EXIST_ERROR can be caused by a concurrent
+ writer. Check if there was one by checking if the name list
+ changed.
+ */
+ err2 = read_lines(st->list_file, &names_after);
+ if (err2 < 0) {
+ free_names(names);
+ return err2;
+ }
+
+ if (names_equal(names_after, names)) {
+ free_names(names);
+ free_names(names_after);
+ return err;
+ }
+ free_names(names);
+ free_names(names_after);
+
+ delay = delay + (delay * rand()) / RAND_MAX + 1;
+ sleep_millisec(delay);
+ }
+
+ return 0;
+}
+
+/* -1 = error
+ 0 = up to date
+ 1 = changed. */
+static int stack_uptodate(struct reftable_stack *st)
+{
+ char **names = NULL;
+ int err = read_lines(st->list_file, &names);
+ int i = 0;
+ 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->stack_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_LOCK_ERROR) {
+ /* Ignore error return, we want to propagate
+ REFTABLE_LOCK_ERROR.
+ */
+ reftable_stack_reload(st);
+ }
+ return err;
+ }
+
+ if (!st->disable_auto_compact)
+ return reftable_stack_auto_compact(st);
+
+ return 0;
+}
+
+static void format_name(struct strbuf *dest, uint64_t min, uint64_t max)
+{
+ char buf[100];
+ uint32_t rnd = (uint32_t)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 {
+ int lock_file_fd;
+ struct strbuf lock_file_name;
+ struct reftable_stack *stack;
+
+ char **new_tables;
+ int new_tables_len;
+ uint64_t next_update_index;
+};
+
+#define REFTABLE_ADDITION_INIT \
+ { \
+ .lock_file_name = STRBUF_INIT \
+ }
+
+static int reftable_stack_init_addition(struct reftable_addition *add,
+ struct reftable_stack *st)
+{
+ int err = 0;
+ add->stack = st;
+
+ strbuf_reset(&add->lock_file_name);
+ strbuf_addstr(&add->lock_file_name, st->list_file);
+ strbuf_addstr(&add->lock_file_name, ".lock");
+
+ add->lock_file_fd = open(add->lock_file_name.buf,
+ O_EXCL | O_CREAT | O_WRONLY, 0644);
+ if (add->lock_file_fd < 0) {
+ if (errno == EEXIST) {
+ err = REFTABLE_LOCK_ERROR;
+ } else {
+ err = REFTABLE_IO_ERROR;
+ }
+ goto done;
+ }
+ err = stack_uptodate(st);
+ if (err < 0)
+ goto done;
+
+ if (err > 1) {
+ err = REFTABLE_LOCK_ERROR;
+ goto done;
+ }
+
+ add->next_update_index = reftable_stack_next_update_index(st);
+done:
+ if (err) {
+ reftable_addition_close(add);
+ }
+ return err;
+}
+
+static void reftable_addition_close(struct reftable_addition *add)
+{
+ int i = 0;
+ struct strbuf nm = STRBUF_INIT;
+ 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;
+
+ if (add->lock_file_fd > 0) {
+ close(add->lock_file_fd);
+ add->lock_file_fd = 0;
+ }
+ if (add->lock_file_name.len > 0) {
+ unlink(add->lock_file_name.buf);
+ strbuf_release(&add->lock_file_name);
+ }
+
+ 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 i = 0;
+ int err = 0;
+ if (add->new_tables_len == 0)
+ goto done;
+
+ for (i = 0; i < add->stack->merged->stack_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(add->lock_file_fd, table_list.buf, table_list.len);
+ strbuf_release(&table_list);
+ if (err < 0) {
+ err = REFTABLE_IO_ERROR;
+ goto done;
+ }
+
+ err = close(add->lock_file_fd);
+ add->lock_file_fd = 0;
+ if (err < 0) {
+ err = REFTABLE_IO_ERROR;
+ goto done;
+ }
+
+ err = rename(add->lock_file_name.buf, add->stack->list_file);
+ if (err < 0) {
+ err = REFTABLE_IO_ERROR;
+ goto done;
+ }
+
+ /* success, no more state to clean up. */
+ strbuf_release(&add->lock_file_name);
+ 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;
+
+ err = reftable_stack_reload(add->stack);
+done:
+ reftable_addition_close(add);
+ return err;
+}
+
+int reftable_stack_new_addition(struct reftable_addition **dest,
+ struct reftable_stack *st)
+{
+ int err = 0;
+ struct reftable_addition empty = REFTABLE_ADDITION_INIT;
+ *dest = reftable_calloc(sizeof(**dest));
+ **dest = empty;
+ err = reftable_stack_init_addition(*dest, st);
+ 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);
+ if (err < 0)
+ goto done;
+ if (err > 0) {
+ err = REFTABLE_LOCK_ERROR;
+ 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;
+ int err = 0;
+ int tab_fd = 0;
+
+ 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_fd = mkstemp(temp_tab_file_name.buf);
+ if (tab_fd < 0) {
+ err = REFTABLE_IO_ERROR;
+ goto done;
+ }
+
+ wr = reftable_new_writer(reftable_fd_write, &tab_fd,
+ &add->stack->config);
+ 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(tab_fd);
+ tab_fd = 0;
+ if (err < 0) {
+ err = REFTABLE_IO_ERROR;
+ goto done;
+ }
+
+ err = stack_check_addition(add->stack, temp_tab_file_name.buf);
+ if (err < 0)
+ 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(temp_tab_file_name.buf, tab_file_name.buf);
+ if (err < 0) {
+ err = REFTABLE_IO_ERROR;
+ goto done;
+ }
+
+ add->new_tables = reftable_realloc(add->new_tables,
+ sizeof(*add->new_tables) *
+ (add->new_tables_len + 1));
+ add->new_tables[add->new_tables_len] = strbuf_detach(&next_name, NULL);
+ add->new_tables_len++;
+done:
+ if (tab_fd > 0) {
+ close(tab_fd);
+ tab_fd = 0;
+ }
+ if (temp_tab_file_name.len > 0) {
+ unlink(temp_tab_file_name.buf);
+ }
+
+ 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->stack_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, int first, int last,
+ struct strbuf *temp_tab,
+ struct reftable_log_expiry_config *config)
+{
+ struct strbuf next_name = STRBUF_INIT;
+ int tab_fd = -1;
+ struct reftable_writer *wr = NULL;
+ int err = 0;
+
+ format_name(&next_name,
+ reftable_reader_min_update_index(st->readers[first]),
+ reftable_reader_max_update_index(st->readers[last]));
+
+ stack_filename(temp_tab, st, next_name.buf);
+ strbuf_addstr(temp_tab, ".temp.XXXXXX");
+
+ tab_fd = mkstemp(temp_tab->buf);
+ wr = reftable_new_writer(reftable_fd_write, &tab_fd, &st->config);
+
+ 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(tab_fd);
+ tab_fd = 0;
+
+done:
+ reftable_writer_free(wr);
+ if (tab_fd > 0) {
+ close(tab_fd);
+ tab_fd = 0;
+ }
+ if (err != 0 && temp_tab->len > 0) {
+ unlink(temp_tab->buf);
+ strbuf_release(temp_tab);
+ }
+ strbuf_release(&next_name);
+ return err;
+}
+
+static int stack_write_compact(struct reftable_stack *st,
+ struct reftable_writer *wr, int first, int last,
+ struct reftable_log_expiry_config *config)
+{
+ int subtabs_len = last - first + 1;
+ struct reftable_table *subtabs = reftable_calloc(
+ sizeof(struct reftable_table) * (last - first + 1));
+ struct reftable_merged_table *mt = NULL;
+ int err = 0;
+ struct reftable_iterator it = { NULL };
+ struct reftable_ref_record ref = { NULL };
+ struct reftable_log_record log = { NULL };
+
+ uint64_t entries = 0;
+
+ int i = 0, j = 0;
+ for (i = first, j = 0; i <= last; i++) {
+ struct reftable_reader *t = st->readers[i];
+ reftable_table_from_reader(&subtabs[j++], t);
+ st->stats.bytes += t->size;
+ }
+ reftable_writer_set_limits(wr, st->readers[first]->min_update_index,
+ st->readers[last]->max_update_index);
+
+ err = reftable_new_merged_table(&mt, subtabs, subtabs_len,
+ st->config.hash_id);
+ if (err < 0) {
+ reftable_free(subtabs);
+ goto done;
+ }
+
+ err = reftable_merged_table_seek_ref(mt, &it, "");
+ if (err < 0)
+ goto done;
+
+ while (1) {
+ err = reftable_iterator_next_ref(&it, &ref);
+ if (err > 0) {
+ err = 0;
+ break;
+ }
+ if (err < 0) {
+ break;
+ }
+
+ if (first == 0 && reftable_ref_record_is_deletion(&ref)) {
+ continue;
+ }
+
+ err = reftable_writer_add_ref(wr, &ref);
+ if (err < 0) {
+ break;
+ }
+ entries++;
+ }
+ reftable_iterator_destroy(&it);
+
+ err = reftable_merged_table_seek_log(mt, &it, "");
+ if (err < 0)
+ goto done;
+
+ while (1) {
+ err = reftable_iterator_next_log(&it, &log);
+ if (err > 0) {
+ err = 0;
+ break;
+ }
+ if (err < 0) {
+ break;
+ }
+ 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 &&
+ log.value.update.time < config->time) {
+ continue;
+ }
+
+ err = reftable_writer_add_log(wr, &log);
+ if (err < 0) {
+ break;
+ }
+ entries++;
+ }
+
+done:
+ reftable_iterator_destroy(&it);
+ if (mt) {
+ merged_table_release(mt);
+ reftable_merged_table_free(mt);
+ }
+ reftable_ref_record_release(&ref);
+ reftable_log_record_release(&log);
+ st->stats.entries_written += entries;
+ return err;
+}
+
+/* < 0: error. 0 == OK, > 0 attempt failed; could retry. */
+static int stack_compact_range(struct reftable_stack *st, int first, int last,
+ struct reftable_log_expiry_config *expiry)
+{
+ struct strbuf temp_tab_file_name = STRBUF_INIT;
+ struct strbuf new_table_name = STRBUF_INIT;
+ struct strbuf lock_file_name = STRBUF_INIT;
+ struct strbuf ref_list_contents = STRBUF_INIT;
+ struct strbuf new_table_path = STRBUF_INIT;
+ int err = 0;
+ int have_lock = 0;
+ int lock_file_fd = 0;
+ int compact_count = last - first + 1;
+ char **listp = NULL;
+ char **delete_on_success =
+ reftable_calloc(sizeof(char *) * (compact_count + 1));
+ char **subtable_locks =
+ reftable_calloc(sizeof(char *) * (compact_count + 1));
+ int i = 0;
+ int j = 0;
+ int is_empty_table = 0;
+
+ if (first > last || (!expiry && first == last)) {
+ err = 0;
+ goto done;
+ }
+
+ st->stats.attempts++;
+
+ strbuf_reset(&lock_file_name);
+ strbuf_addstr(&lock_file_name, st->list_file);
+ strbuf_addstr(&lock_file_name, ".lock");
+
+ lock_file_fd =
+ open(lock_file_name.buf, O_EXCL | O_CREAT | O_WRONLY, 0644);
+ if (lock_file_fd < 0) {
+ if (errno == EEXIST) {
+ err = 1;
+ } else {
+ err = REFTABLE_IO_ERROR;
+ }
+ goto done;
+ }
+ /* Don't want to write to the lock for now. */
+ close(lock_file_fd);
+ lock_file_fd = 0;
+
+ have_lock = 1;
+ err = stack_uptodate(st);
+ if (err != 0)
+ goto done;
+
+ for (i = first, j = 0; i <= last; i++) {
+ struct strbuf subtab_file_name = STRBUF_INIT;
+ struct strbuf subtab_lock = STRBUF_INIT;
+ int sublock_file_fd = -1;
+
+ stack_filename(&subtab_file_name, st,
+ reader_name(st->readers[i]));
+
+ strbuf_reset(&subtab_lock);
+ strbuf_addbuf(&subtab_lock, &subtab_file_name);
+ strbuf_addstr(&subtab_lock, ".lock");
+
+ sublock_file_fd = open(subtab_lock.buf,
+ O_EXCL | O_CREAT | O_WRONLY, 0644);
+ if (sublock_file_fd > 0) {
+ close(sublock_file_fd);
+ } else if (sublock_file_fd < 0) {
+ if (errno == EEXIST) {
+ err = 1;
+ } else {
+ err = REFTABLE_IO_ERROR;
+ }
+ }
+
+ subtable_locks[j] = subtab_lock.buf;
+ delete_on_success[j] = subtab_file_name.buf;
+ j++;
+
+ if (err != 0)
+ goto done;
+ }
+
+ err = unlink(lock_file_name.buf);
+ if (err < 0)
+ goto done;
+ have_lock = 0;
+
+ err = stack_compact_locked(st, first, last, &temp_tab_file_name,
+ expiry);
+ /* Compaction + tombstones can create an empty table out of non-empty
+ * tables. */
+ is_empty_table = (err == REFTABLE_EMPTY_TABLE_ERROR);
+ if (is_empty_table) {
+ err = 0;
+ }
+ if (err < 0)
+ goto done;
+
+ lock_file_fd =
+ open(lock_file_name.buf, O_EXCL | O_CREAT | O_WRONLY, 0644);
+ if (lock_file_fd < 0) {
+ if (errno == EEXIST) {
+ err = 1;
+ } else {
+ err = REFTABLE_IO_ERROR;
+ }
+ goto done;
+ }
+ have_lock = 1;
+
+ format_name(&new_table_name, st->readers[first]->min_update_index,
+ st->readers[last]->max_update_index);
+ strbuf_addstr(&new_table_name, ".ref");
+
+ stack_filename(&new_table_path, st, new_table_name.buf);
+
+ if (!is_empty_table) {
+ /* retry? */
+ err = rename(temp_tab_file_name.buf, new_table_path.buf);
+ if (err < 0) {
+ err = REFTABLE_IO_ERROR;
+ goto done;
+ }
+ }
+
+ for (i = 0; i < first; i++) {
+ strbuf_addstr(&ref_list_contents, st->readers[i]->name);
+ strbuf_addstr(&ref_list_contents, "\n");
+ }
+ if (!is_empty_table) {
+ strbuf_addbuf(&ref_list_contents, &new_table_name);
+ strbuf_addstr(&ref_list_contents, "\n");
+ }
+ for (i = last + 1; i < st->merged->stack_len; i++) {
+ strbuf_addstr(&ref_list_contents, st->readers[i]->name);
+ strbuf_addstr(&ref_list_contents, "\n");
+ }
+
+ err = write(lock_file_fd, ref_list_contents.buf, ref_list_contents.len);
+ if (err < 0) {
+ err = REFTABLE_IO_ERROR;
+ unlink(new_table_path.buf);
+ goto done;
+ }
+ err = close(lock_file_fd);
+ lock_file_fd = 0;
+ if (err < 0) {
+ err = REFTABLE_IO_ERROR;
+ unlink(new_table_path.buf);
+ goto done;
+ }
+
+ err = rename(lock_file_name.buf, st->list_file);
+ if (err < 0) {
+ err = REFTABLE_IO_ERROR;
+ unlink(new_table_path.buf);
+ goto done;
+ }
+ have_lock = 0;
+
+ /* Reload the stack before deleting. On windows, we can only delete the
+ files after we closed them.
+ */
+ err = reftable_stack_reload_maybe_reuse(st, first < last);
+
+ listp = delete_on_success;
+ while (*listp) {
+ if (strcmp(*listp, new_table_path.buf)) {
+ unlink(*listp);
+ }
+ listp++;
+ }
+
+done:
+ free_names(delete_on_success);
+
+ listp = subtable_locks;
+ while (*listp) {
+ unlink(*listp);
+ listp++;
+ }
+ free_names(subtable_locks);
+ if (lock_file_fd > 0) {
+ close(lock_file_fd);
+ lock_file_fd = 0;
+ }
+ if (have_lock) {
+ unlink(lock_file_name.buf);
+ }
+ strbuf_release(&new_table_name);
+ strbuf_release(&new_table_path);
+ strbuf_release(&ref_list_contents);
+ strbuf_release(&temp_tab_file_name);
+ strbuf_release(&lock_file_name);
+ return err;
+}
+
+int reftable_stack_compact_all(struct reftable_stack *st,
+ struct reftable_log_expiry_config *config)
+{
+ return stack_compact_range(st, 0, st->merged->stack_len - 1, config);
+}
+
+static int stack_compact_range_stats(struct reftable_stack *st, int first,
+ int last,
+ struct reftable_log_expiry_config *config)
+{
+ int err = stack_compact_range(st, first, last, config);
+ if (err > 0) {
+ st->stats.failures++;
+ }
+ return err;
+}
+
+static int segment_size(struct segment *s)
+{
+ return s->end - s->start;
+}
+
+int fastlog2(uint64_t sz)
+{
+ int l = 0;
+ if (sz == 0)
+ return 0;
+ for (; sz; sz /= 2) {
+ l++;
+ }
+ return l - 1;
+}
+
+struct segment *sizes_to_segments(int *seglen, uint64_t *sizes, int n)
+{
+ struct segment *segs = reftable_calloc(sizeof(struct segment) * n);
+ int next = 0;
+ struct segment cur = { 0 };
+ int i = 0;
+
+ if (n == 0) {
+ *seglen = 0;
+ return segs;
+ }
+ for (i = 0; i < n; i++) {
+ int log = fastlog2(sizes[i]);
+ if (cur.log != log && cur.bytes > 0) {
+ struct segment fresh = {
+ .start = i,
+ };
+
+ segs[next++] = cur;
+ cur = fresh;
+ }
+
+ cur.log = log;
+ cur.end = i + 1;
+ cur.bytes += sizes[i];
+ }
+ segs[next++] = cur;
+ *seglen = next;
+ return segs;
+}
+
+struct segment suggest_compaction_segment(uint64_t *sizes, int n)
+{
+ int seglen = 0;
+ struct segment *segs = sizes_to_segments(&seglen, sizes, n);
+ struct segment min_seg = {
+ .log = 64,
+ };
+ int i = 0;
+ for (i = 0; i < seglen; i++) {
+ if (segment_size(&segs[i]) == 1) {
+ continue;
+ }
+
+ if (segs[i].log < min_seg.log) {
+ min_seg = segs[i];
+ }
+ }
+
+ while (min_seg.start > 0) {
+ int prev = min_seg.start - 1;
+ if (fastlog2(min_seg.bytes) < fastlog2(sizes[prev])) {
+ break;
+ }
+
+ min_seg.start = prev;
+ min_seg.bytes += sizes[prev];
+ }
+
+ reftable_free(segs);
+ return min_seg;
+}
+
+static uint64_t *stack_table_sizes_for_compaction(struct reftable_stack *st)
+{
+ uint64_t *sizes =
+ reftable_calloc(sizeof(uint64_t) * st->merged->stack_len);
+ int version = (st->config.hash_id == GIT_SHA1_FORMAT_ID) ? 1 : 2;
+ int overhead = header_size(version) - 1;
+ int i = 0;
+ for (i = 0; i < st->merged->stack_len; i++) {
+ sizes[i] = st->readers[i]->size - overhead;
+ }
+ return sizes;
+}
+
+int reftable_stack_auto_compact(struct reftable_stack *st)
+{
+ uint64_t *sizes = stack_table_sizes_for_compaction(st);
+ struct segment seg =
+ suggest_compaction_segment(sizes, st->merged->stack_len);
+ reftable_free(sizes);
+ if (segment_size(&seg) > 0)
+ return stack_compact_range_stats(st, seg.start, seg.end - 1,
+ NULL);
+
+ return 0;
+}
+
+struct reftable_compaction_stats *
+reftable_stack_compaction_stats(struct reftable_stack *st)
+{
+ return &st->stats;
+}
+
+int reftable_stack_read_ref(struct reftable_stack *st, const char *refname,
+ struct reftable_ref_record *ref)
+{
+ struct reftable_table tab = { NULL };
+ reftable_table_from_merged_table(&tab, reftable_stack_merged_table(st));
+ return reftable_table_read_ref(&tab, refname, ref);
+}
+
+int reftable_stack_read_log(struct reftable_stack *st, const char *refname,
+ struct reftable_log_record *log)
+{
+ struct reftable_iterator it = { NULL };
+ struct reftable_merged_table *mt = reftable_stack_merged_table(st);
+ int err = reftable_merged_table_seek_log(mt, &it, refname);
+ if (err)
+ goto done;
+
+ err = reftable_iterator_next_log(&it, log);
+ if (err)
+ goto done;
+
+ if (strcmp(log->refname, refname) ||
+ reftable_log_record_is_deletion(log)) {
+ err = 1;
+ goto done;
+ }
+
+done:
+ if (err) {
+ reftable_log_record_release(log);
+ }
+ reftable_iterator_destroy(&it);
+ return err;
+}
+
+static int stack_check_addition(struct reftable_stack *st,
+ const char *new_tab_name)
+{
+ int err = 0;
+ struct reftable_block_source src = { NULL };
+ struct reftable_reader *rd = NULL;
+ struct reftable_table tab = { NULL };
+ struct reftable_ref_record *refs = NULL;
+ struct reftable_iterator it = { NULL };
+ int cap = 0;
+ int len = 0;
+ int i = 0;
+
+ if (st->config.skip_name_check)
+ return 0;
+
+ err = reftable_block_source_from_file(&src, new_tab_name);
+ if (err < 0)
+ goto done;
+
+ err = reftable_new_reader(&rd, &src, new_tab_name);
+ if (err < 0)
+ goto done;
+
+ err = reftable_reader_seek_ref(rd, &it, "");
+ if (err > 0) {
+ err = 0;
+ goto done;
+ }
+ if (err < 0)
+ goto done;
+
+ while (1) {
+ struct reftable_ref_record ref = { NULL };
+ err = reftable_iterator_next_ref(&it, &ref);
+ if (err > 0) {
+ break;
+ }
+ if (err < 0)
+ goto done;
+
+ if (len >= cap) {
+ cap = 2 * cap + 1;
+ refs = reftable_realloc(refs, cap * sizeof(refs[0]));
+ }
+
+ refs[len++] = ref;
+ }
+
+ reftable_table_from_merged_table(&tab, reftable_stack_merged_table(st));
+
+ err = validate_ref_record_addition(tab, refs, len);
+
+done:
+ for (i = 0; i < len; i++) {
+ reftable_ref_record_release(&refs[i]);
+ }
+
+ free(refs);
+ reftable_iterator_destroy(&it);
+ reftable_reader_free(rd);
+ return err;
+}
+
+static int is_table_name(const char *s)
+{
+ const char *dot = strrchr(s, '.');
+ return dot && !strcmp(dot, ".ref");
+}
+
+static void remove_maybe_stale_table(struct reftable_stack *st, uint64_t max,
+ const char *name)
+{
+ int err = 0;
+ uint64_t update_idx = 0;
+ struct reftable_block_source src = { NULL };
+ struct reftable_reader *rd = NULL;
+ struct strbuf table_path = STRBUF_INIT;
+ stack_filename(&table_path, st, name);
+
+ err = reftable_block_source_from_file(&src, table_path.buf);
+ if (err < 0)
+ goto done;
+
+ err = reftable_new_reader(&rd, &src, name);
+ if (err < 0)
+ goto done;
+
+ update_idx = reftable_reader_max_update_index(rd);
+ reftable_reader_free(rd);
+
+ if (update_idx <= max) {
+ unlink(table_path.buf);
+ }
+done:
+ strbuf_release(&table_path);
+}
+
+static int reftable_stack_clean_locked(struct reftable_stack *st)
+{
+ uint64_t max = reftable_merged_table_max_update_index(
+ reftable_stack_merged_table(st));
+ DIR *dir = opendir(st->reftable_dir);
+ struct dirent *d = NULL;
+ if (!dir) {
+ return REFTABLE_IO_ERROR;
+ }
+
+ while ((d = readdir(dir))) {
+ int i = 0;
+ int found = 0;
+ if (!is_table_name(d->d_name))
+ continue;
+
+ for (i = 0; !found && i < st->readers_len; i++) {
+ found = !strcmp(reader_name(st->readers[i]), d->d_name);
+ }
+ if (found)
+ continue;
+
+ remove_maybe_stale_table(st, max, d->d_name);
+ }
+
+ closedir(dir);
+ return 0;
+}
+
+int reftable_stack_clean(struct reftable_stack *st)
+{
+ struct reftable_addition *add = NULL;
+ int err = reftable_stack_new_addition(&add, st);
+ if (err < 0) {
+ goto done;
+ }
+
+ err = reftable_stack_reload(st);
+ if (err < 0) {
+ goto done;
+ }
+
+ err = reftable_stack_clean_locked(st);
+
+done:
+ reftable_addition_destroy(add);
+ return err;
+}
+
+int reftable_stack_print_directory(const char *stackdir, uint32_t hash_id)
+{
+ struct reftable_stack *stack = NULL;
+ struct reftable_write_options cfg = { .hash_id = hash_id };
+ struct reftable_merged_table *merged = NULL;
+ struct reftable_table table = { NULL };
+
+ int err = reftable_new_stack(&stack, stackdir, cfg);
+ if (err < 0)
+ goto done;
+
+ merged = reftable_stack_merged_table(stack);
+ reftable_table_from_merged_table(&table, merged);
+ err = reftable_table_print(&table);
+done:
+ if (stack)
+ reftable_stack_destroy(stack);
+ return err;
+}