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reftable: add merged table view

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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>
This commit is contained in:
Han-Wen Nienhuys 2021-10-07 20:25:11 +00:00 committed by Junio C Hamano
parent 3b34f636df
commit 1ae2b8cda8
6 changed files with 943 additions and 0 deletions
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2
Makefile
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@ -2462,6 +2462,7 @@ REFTABLE_OBJS += reftable/block.o
REFTABLE_OBJS += reftable/blocksource.o REFTABLE_OBJS += reftable/blocksource.o
REFTABLE_OBJS += reftable/iter.o REFTABLE_OBJS += reftable/iter.o
REFTABLE_OBJS += reftable/publicbasics.o REFTABLE_OBJS += reftable/publicbasics.o
REFTABLE_OBJS += reftable/merged.o
REFTABLE_OBJS += reftable/pq.o REFTABLE_OBJS += reftable/pq.o
REFTABLE_OBJS += reftable/reader.o REFTABLE_OBJS += reftable/reader.o
REFTABLE_OBJS += reftable/record.o REFTABLE_OBJS += reftable/record.o
@ -2473,6 +2474,7 @@ REFTABLE_OBJS += reftable/writer.o
REFTABLE_TEST_OBJS += reftable/basics_test.o REFTABLE_TEST_OBJS += reftable/basics_test.o
REFTABLE_TEST_OBJS += reftable/block_test.o REFTABLE_TEST_OBJS += reftable/block_test.o
REFTABLE_TEST_OBJS += reftable/merged_test.o
REFTABLE_TEST_OBJS += reftable/pq_test.o REFTABLE_TEST_OBJS += reftable/pq_test.o
REFTABLE_TEST_OBJS += reftable/record_test.o REFTABLE_TEST_OBJS += reftable/record_test.o
REFTABLE_TEST_OBJS += reftable/readwrite_test.o REFTABLE_TEST_OBJS += reftable/readwrite_test.o

362
reftable/merged.c Normal file
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@ -0,0 +1,362 @@
/*
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 "merged.h"
#include "constants.h"
#include "iter.h"
#include "pq.h"
#include "reader.h"
#include "record.h"
#include "generic.h"
#include "reftable-merged.h"
#include "reftable-error.h"
#include "system.h"
static int merged_iter_init(struct merged_iter *mi)
{
int i = 0;
for (i = 0; i < mi->stack_len; i++) {
struct reftable_record rec = reftable_new_record(mi->typ);
int err = iterator_next(&mi->stack[i], &rec);
if (err < 0) {
return err;
}
if (err > 0) {
reftable_iterator_destroy(&mi->stack[i]);
reftable_record_destroy(&rec);
} else {
struct pq_entry e = {
.rec = rec,
.index = i,
};
merged_iter_pqueue_add(&mi->pq, e);
}
}
return 0;
}
static void merged_iter_close(void *p)
{
struct merged_iter *mi = p;
int i = 0;
merged_iter_pqueue_release(&mi->pq);
for (i = 0; i < mi->stack_len; i++) {
reftable_iterator_destroy(&mi->stack[i]);
}
reftable_free(mi->stack);
}
static int merged_iter_advance_nonnull_subiter(struct merged_iter *mi,
size_t idx)
{
struct reftable_record rec = reftable_new_record(mi->typ);
struct pq_entry e = {
.rec = rec,
.index = idx,
};
int err = iterator_next(&mi->stack[idx], &rec);
if (err < 0)
return err;
if (err > 0) {
reftable_iterator_destroy(&mi->stack[idx]);
reftable_record_destroy(&rec);
return 0;
}
merged_iter_pqueue_add(&mi->pq, e);
return 0;
}
static int merged_iter_advance_subiter(struct merged_iter *mi, size_t idx)
{
if (iterator_is_null(&mi->stack[idx]))
return 0;
return merged_iter_advance_nonnull_subiter(mi, idx);
}
static int merged_iter_next_entry(struct merged_iter *mi,
struct reftable_record *rec)
{
struct strbuf entry_key = STRBUF_INIT;
struct pq_entry entry = { 0 };
int err = 0;
if (merged_iter_pqueue_is_empty(mi->pq))
return 1;
entry = merged_iter_pqueue_remove(&mi->pq);
err = merged_iter_advance_subiter(mi, entry.index);
if (err < 0)
return err;
/*
One can also use reftable as datacenter-local storage, where the ref
database is maintained in globally consistent database (eg.
CockroachDB or Spanner). In this scenario, replication delays together
with compaction may cause newer tables to contain older entries. In
such a deployment, the loop below must be changed to collect all
entries for the same key, and return new the newest one.
*/
reftable_record_key(&entry.rec, &entry_key);
while (!merged_iter_pqueue_is_empty(mi->pq)) {
struct pq_entry top = merged_iter_pqueue_top(mi->pq);
struct strbuf k = STRBUF_INIT;
int err = 0, cmp = 0;
reftable_record_key(&top.rec, &k);
cmp = strbuf_cmp(&k, &entry_key);
strbuf_release(&k);
if (cmp > 0) {
break;
}
merged_iter_pqueue_remove(&mi->pq);
err = merged_iter_advance_subiter(mi, top.index);
if (err < 0) {
return err;
}
reftable_record_destroy(&top.rec);
}
reftable_record_copy_from(rec, &entry.rec, hash_size(mi->hash_id));
reftable_record_destroy(&entry.rec);
strbuf_release(&entry_key);
return 0;
}
static int merged_iter_next(struct merged_iter *mi, struct reftable_record *rec)
{
while (1) {
int err = merged_iter_next_entry(mi, rec);
if (err == 0 && mi->suppress_deletions &&
reftable_record_is_deletion(rec)) {
continue;
}
return err;
}
}
static int merged_iter_next_void(void *p, struct reftable_record *rec)
{
struct merged_iter *mi = p;
if (merged_iter_pqueue_is_empty(mi->pq))
return 1;
return merged_iter_next(mi, rec);
}
static struct reftable_iterator_vtable merged_iter_vtable = {
.next = &merged_iter_next_void,
.close = &merged_iter_close,
};
static void iterator_from_merged_iter(struct reftable_iterator *it,
struct merged_iter *mi)
{
assert(!it->ops);
it->iter_arg = mi;
it->ops = &merged_iter_vtable;
}
int reftable_new_merged_table(struct reftable_merged_table **dest,
struct reftable_table *stack, int n,
uint32_t hash_id)
{
struct reftable_merged_table *m = NULL;
uint64_t last_max = 0;
uint64_t first_min = 0;
int i = 0;
for (i = 0; i < n; i++) {
uint64_t min = reftable_table_min_update_index(&stack[i]);
uint64_t max = reftable_table_max_update_index(&stack[i]);
if (reftable_table_hash_id(&stack[i]) != hash_id) {
return REFTABLE_FORMAT_ERROR;
}
if (i == 0 || min < first_min) {
first_min = min;
}
if (i == 0 || max > last_max) {
last_max = max;
}
}
m = reftable_calloc(sizeof(struct reftable_merged_table));
m->stack = stack;
m->stack_len = n;
m->min = first_min;
m->max = last_max;
m->hash_id = hash_id;
*dest = m;
return 0;
}
/* clears the list of subtable, without affecting the readers themselves. */
void merged_table_release(struct reftable_merged_table *mt)
{
FREE_AND_NULL(mt->stack);
mt->stack_len = 0;
}
void reftable_merged_table_free(struct reftable_merged_table *mt)
{
if (!mt) {
return;
}
merged_table_release(mt);
reftable_free(mt);
}
uint64_t
reftable_merged_table_max_update_index(struct reftable_merged_table *mt)
{
return mt->max;
}
uint64_t
reftable_merged_table_min_update_index(struct reftable_merged_table *mt)
{
return mt->min;
}
static int reftable_table_seek_record(struct reftable_table *tab,
struct reftable_iterator *it,
struct reftable_record *rec)
{
return tab->ops->seek_record(tab->table_arg, it, rec);
}
static int merged_table_seek_record(struct reftable_merged_table *mt,
struct reftable_iterator *it,
struct reftable_record *rec)
{
struct reftable_iterator *iters = reftable_calloc(
sizeof(struct reftable_iterator) * mt->stack_len);
struct merged_iter merged = {
.stack = iters,
.typ = reftable_record_type(rec),
.hash_id = mt->hash_id,
.suppress_deletions = mt->suppress_deletions,
};
int n = 0;
int err = 0;
int i = 0;
for (i = 0; i < mt->stack_len && err == 0; i++) {
int e = reftable_table_seek_record(&mt->stack[i], &iters[n],
rec);
if (e < 0) {
err = e;
}
if (e == 0) {
n++;
}
}
if (err < 0) {
int i = 0;
for (i = 0; i < n; i++) {
reftable_iterator_destroy(&iters[i]);
}
reftable_free(iters);
return err;
}
merged.stack_len = n;
err = merged_iter_init(&merged);
if (err < 0) {
merged_iter_close(&merged);
return err;
} else {
struct merged_iter *p =
reftable_malloc(sizeof(struct merged_iter));
*p = merged;
iterator_from_merged_iter(it, p);
}
return 0;
}
int reftable_merged_table_seek_ref(struct reftable_merged_table *mt,
struct reftable_iterator *it,
const char *name)
{
struct reftable_ref_record ref = {
.refname = (char *)name,
};
struct reftable_record rec = { NULL };
reftable_record_from_ref(&rec, &ref);
return merged_table_seek_record(mt, it, &rec);
}
int reftable_merged_table_seek_log_at(struct reftable_merged_table *mt,
struct reftable_iterator *it,
const char *name, uint64_t update_index)
{
struct reftable_log_record log = {
.refname = (char *)name,
.update_index = update_index,
};
struct reftable_record rec = { NULL };
reftable_record_from_log(&rec, &log);
return merged_table_seek_record(mt, it, &rec);
}
int reftable_merged_table_seek_log(struct reftable_merged_table *mt,
struct reftable_iterator *it,
const char *name)
{
uint64_t max = ~((uint64_t)0);
return reftable_merged_table_seek_log_at(mt, it, name, max);
}
uint32_t reftable_merged_table_hash_id(struct reftable_merged_table *mt)
{
return mt->hash_id;
}
static int reftable_merged_table_seek_void(void *tab,
struct reftable_iterator *it,
struct reftable_record *rec)
{
return merged_table_seek_record(tab, it, rec);
}
static uint32_t reftable_merged_table_hash_id_void(void *tab)
{
return reftable_merged_table_hash_id(tab);
}
static uint64_t reftable_merged_table_min_update_index_void(void *tab)
{
return reftable_merged_table_min_update_index(tab);
}
static uint64_t reftable_merged_table_max_update_index_void(void *tab)
{
return reftable_merged_table_max_update_index(tab);
}
static struct reftable_table_vtable merged_table_vtable = {
.seek_record = reftable_merged_table_seek_void,
.hash_id = reftable_merged_table_hash_id_void,
.min_update_index = reftable_merged_table_min_update_index_void,
.max_update_index = reftable_merged_table_max_update_index_void,
};
void reftable_table_from_merged_table(struct reftable_table *tab,
struct reftable_merged_table *merged)
{
assert(!tab->ops);
tab->ops = &merged_table_vtable;
tab->table_arg = merged;
}

38
reftable/merged.h Normal file
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@ -0,0 +1,38 @@
/*
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
*/
#ifndef MERGED_H
#define MERGED_H
#include "pq.h"
struct reftable_merged_table {
struct reftable_table *stack;
size_t stack_len;
uint32_t hash_id;
/* If unset, produce deletions. This is useful for compaction. For the
* full stack, deletions should be produced. */
int suppress_deletions;
uint64_t min;
uint64_t max;
};
struct merged_iter {
struct reftable_iterator *stack;
uint32_t hash_id;
size_t stack_len;
uint8_t typ;
int suppress_deletions;
struct merged_iter_pqueue pq;
};
void merged_table_release(struct reftable_merged_table *mt);
#endif

468
reftable/merged_test.c Normal file
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@ -0,0 +1,468 @@
/*
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 "merged.h"
#include "system.h"
#include "basics.h"
#include "blocksource.h"
#include "constants.h"
#include "reader.h"
#include "record.h"
#include "test_framework.h"
#include "reftable-merged.h"
#include "reftable-tests.h"
#include "reftable-generic.h"
#include "reftable-writer.h"
static void write_test_table(struct strbuf *buf,
struct reftable_ref_record refs[], int n)
{
int min = 0xffffffff;
int max = 0;
int i = 0;
int err;
struct reftable_write_options opts = {
.block_size = 256,
};
struct reftable_writer *w = NULL;
for (i = 0; i < n; i++) {
uint64_t ui = refs[i].update_index;
if (ui > max) {
max = ui;
}
if (ui < min) {
min = ui;
}
}
w = reftable_new_writer(&strbuf_add_void, buf, &opts);
reftable_writer_set_limits(w, min, max);
for (i = 0; i < n; i++) {
uint64_t before = refs[i].update_index;
int n = reftable_writer_add_ref(w, &refs[i]);
EXPECT(n == 0);
EXPECT(before == refs[i].update_index);
}
err = reftable_writer_close(w);
EXPECT_ERR(err);
reftable_writer_free(w);
}
static void write_test_log_table(struct strbuf *buf,
struct reftable_log_record logs[], int n,
uint64_t update_index)
{
int i = 0;
int err;
struct reftable_write_options opts = {
.block_size = 256,
.exact_log_message = 1,
};
struct reftable_writer *w = NULL;
w = reftable_new_writer(&strbuf_add_void, buf, &opts);
reftable_writer_set_limits(w, update_index, update_index);
for (i = 0; i < n; i++) {
int err = reftable_writer_add_log(w, &logs[i]);
EXPECT_ERR(err);
}
err = reftable_writer_close(w);
EXPECT_ERR(err);
reftable_writer_free(w);
}
static struct reftable_merged_table *
merged_table_from_records(struct reftable_ref_record **refs,
struct reftable_block_source **source,
struct reftable_reader ***readers, int *sizes,
struct strbuf *buf, int n)
{
int i = 0;
struct reftable_merged_table *mt = NULL;
int err;
struct reftable_table *tabs =
reftable_calloc(n * sizeof(struct reftable_table));
*readers = reftable_calloc(n * sizeof(struct reftable_reader *));
*source = reftable_calloc(n * sizeof(**source));
for (i = 0; i < n; i++) {
write_test_table(&buf[i], refs[i], sizes[i]);
block_source_from_strbuf(&(*source)[i], &buf[i]);
err = reftable_new_reader(&(*readers)[i], &(*source)[i],
"name");
EXPECT_ERR(err);
reftable_table_from_reader(&tabs[i], (*readers)[i]);
}
err = reftable_new_merged_table(&mt, tabs, n, GIT_SHA1_FORMAT_ID);
EXPECT_ERR(err);
return mt;
}
static void readers_destroy(struct reftable_reader **readers, size_t n)
{
int i = 0;
for (; i < n; i++)
reftable_reader_free(readers[i]);
reftable_free(readers);
}
static void test_merged_between(void)
{
uint8_t hash1[GIT_SHA1_RAWSZ] = { 1, 2, 3, 0 };
struct reftable_ref_record r1[] = { {
.refname = "b",
.update_index = 1,
.value_type = REFTABLE_REF_VAL1,
.value.val1 = hash1,
} };
struct reftable_ref_record r2[] = { {
.refname = "a",
.update_index = 2,
.value_type = REFTABLE_REF_DELETION,
} };
struct reftable_ref_record *refs[] = { r1, r2 };
int sizes[] = { 1, 1 };
struct strbuf bufs[2] = { STRBUF_INIT, STRBUF_INIT };
struct reftable_block_source *bs = NULL;
struct reftable_reader **readers = NULL;
struct reftable_merged_table *mt =
merged_table_from_records(refs, &bs, &readers, sizes, bufs, 2);
int i;
struct reftable_ref_record ref = { NULL };
struct reftable_iterator it = { NULL };
int err = reftable_merged_table_seek_ref(mt, &it, "a");
EXPECT_ERR(err);
err = reftable_iterator_next_ref(&it, &ref);
EXPECT_ERR(err);
EXPECT(ref.update_index == 2);
reftable_ref_record_release(&ref);
reftable_iterator_destroy(&it);
readers_destroy(readers, 2);
reftable_merged_table_free(mt);
for (i = 0; i < ARRAY_SIZE(bufs); i++) {
strbuf_release(&bufs[i]);
}
reftable_free(bs);
}
static void test_merged(void)
{
uint8_t hash1[GIT_SHA1_RAWSZ] = { 1 };
uint8_t hash2[GIT_SHA1_RAWSZ] = { 2 };
struct reftable_ref_record r1[] = {
{
.refname = "a",
.update_index = 1,
.value_type = REFTABLE_REF_VAL1,
.value.val1 = hash1,
},
{
.refname = "b",
.update_index = 1,
.value_type = REFTABLE_REF_VAL1,
.value.val1 = hash1,
},
{
.refname = "c",
.update_index = 1,
.value_type = REFTABLE_REF_VAL1,
.value.val1 = hash1,
}
};
struct reftable_ref_record r2[] = { {
.refname = "a",
.update_index = 2,
.value_type = REFTABLE_REF_DELETION,
} };
struct reftable_ref_record r3[] = {
{
.refname = "c",
.update_index = 3,
.value_type = REFTABLE_REF_VAL1,
.value.val1 = hash2,
},
{
.refname = "d",
.update_index = 3,
.value_type = REFTABLE_REF_VAL1,
.value.val1 = hash1,
},
};
struct reftable_ref_record want[] = {
r2[0],
r1[1],
r3[0],
r3[1],
};
struct reftable_ref_record *refs[] = { r1, r2, r3 };
int sizes[3] = { 3, 1, 2 };
struct strbuf bufs[3] = { STRBUF_INIT, STRBUF_INIT, STRBUF_INIT };
struct reftable_block_source *bs = NULL;
struct reftable_reader **readers = NULL;
struct reftable_merged_table *mt =
merged_table_from_records(refs, &bs, &readers, sizes, bufs, 3);
struct reftable_iterator it = { NULL };
int err = reftable_merged_table_seek_ref(mt, &it, "a");
struct reftable_ref_record *out = NULL;
size_t len = 0;
size_t cap = 0;
int i = 0;
EXPECT_ERR(err);
EXPECT(reftable_merged_table_hash_id(mt) == GIT_SHA1_FORMAT_ID);
EXPECT(reftable_merged_table_min_update_index(mt) == 1);
while (len < 100) { /* cap loops/recursion. */
struct reftable_ref_record ref = { NULL };
int err = reftable_iterator_next_ref(&it, &ref);
if (err > 0) {
break;
}
if (len == cap) {
cap = 2 * cap + 1;
out = reftable_realloc(
out, sizeof(struct reftable_ref_record) * cap);
}
out[len++] = ref;
}
reftable_iterator_destroy(&it);
EXPECT(ARRAY_SIZE(want) == len);
for (i = 0; i < len; i++) {
EXPECT(reftable_ref_record_equal(&want[i], &out[i],
GIT_SHA1_RAWSZ));
}
for (i = 0; i < len; i++) {
reftable_ref_record_release(&out[i]);
}
reftable_free(out);
for (i = 0; i < 3; i++) {
strbuf_release(&bufs[i]);
}
readers_destroy(readers, 3);
reftable_merged_table_free(mt);
reftable_free(bs);
}
static struct reftable_merged_table *
merged_table_from_log_records(struct reftable_log_record **logs,
struct reftable_block_source **source,
struct reftable_reader ***readers, int *sizes,
struct strbuf *buf, int n)
{
int i = 0;
struct reftable_merged_table *mt = NULL;
int err;
struct reftable_table *tabs =
reftable_calloc(n * sizeof(struct reftable_table));
*readers = reftable_calloc(n * sizeof(struct reftable_reader *));
*source = reftable_calloc(n * sizeof(**source));
for (i = 0; i < n; i++) {
write_test_log_table(&buf[i], logs[i], sizes[i], i + 1);
block_source_from_strbuf(&(*source)[i], &buf[i]);
err = reftable_new_reader(&(*readers)[i], &(*source)[i],
"name");
EXPECT_ERR(err);
reftable_table_from_reader(&tabs[i], (*readers)[i]);
}
err = reftable_new_merged_table(&mt, tabs, n, GIT_SHA1_FORMAT_ID);
EXPECT_ERR(err);
return mt;
}
static void test_merged_logs(void)
{
uint8_t hash1[GIT_SHA1_RAWSZ] = { 1 };
uint8_t hash2[GIT_SHA1_RAWSZ] = { 2 };
uint8_t hash3[GIT_SHA1_RAWSZ] = { 3 };
struct reftable_log_record r1[] = {
{
.refname = "a",
.update_index = 2,
.value_type = REFTABLE_LOG_UPDATE,
.value.update = {
.old_hash = hash2,
/* deletion */
.name = "jane doe",
.email = "jane@invalid",
.message = "message2",
}
},
{
.refname = "a",
.update_index = 1,
.value_type = REFTABLE_LOG_UPDATE,
.value.update = {
.old_hash = hash1,
.new_hash = hash2,
.name = "jane doe",
.email = "jane@invalid",
.message = "message1",
}
},
};
struct reftable_log_record r2[] = {
{
.refname = "a",
.update_index = 3,
.value_type = REFTABLE_LOG_UPDATE,
.value.update = {
.new_hash = hash3,
.name = "jane doe",
.email = "jane@invalid",
.message = "message3",
}
},
};
struct reftable_log_record r3[] = {
{
.refname = "a",
.update_index = 2,
.value_type = REFTABLE_LOG_DELETION,
},
};
struct reftable_log_record want[] = {
r2[0],
r3[0],
r1[1],
};
struct reftable_log_record *logs[] = { r1, r2, r3 };
int sizes[3] = { 2, 1, 1 };
struct strbuf bufs[3] = { STRBUF_INIT, STRBUF_INIT, STRBUF_INIT };
struct reftable_block_source *bs = NULL;
struct reftable_reader **readers = NULL;
struct reftable_merged_table *mt = merged_table_from_log_records(
logs, &bs, &readers, sizes, bufs, 3);
struct reftable_iterator it = { NULL };
int err = reftable_merged_table_seek_log(mt, &it, "a");
struct reftable_log_record *out = NULL;
size_t len = 0;
size_t cap = 0;
int i = 0;
EXPECT_ERR(err);
EXPECT(reftable_merged_table_hash_id(mt) == GIT_SHA1_FORMAT_ID);
EXPECT(reftable_merged_table_min_update_index(mt) == 1);
while (len < 100) { /* cap loops/recursion. */
struct reftable_log_record log = { NULL };
int err = reftable_iterator_next_log(&it, &log);
if (err > 0) {
break;
}
if (len == cap) {
cap = 2 * cap + 1;
out = reftable_realloc(
out, sizeof(struct reftable_log_record) * cap);
}
out[len++] = log;
}
reftable_iterator_destroy(&it);
EXPECT(ARRAY_SIZE(want) == len);
for (i = 0; i < len; i++) {
EXPECT(reftable_log_record_equal(&want[i], &out[i],
GIT_SHA1_RAWSZ));
}
err = reftable_merged_table_seek_log_at(mt, &it, "a", 2);
EXPECT_ERR(err);
reftable_log_record_release(&out[0]);
err = reftable_iterator_next_log(&it, &out[0]);
EXPECT_ERR(err);
EXPECT(reftable_log_record_equal(&out[0], &r3[0], GIT_SHA1_RAWSZ));
reftable_iterator_destroy(&it);
for (i = 0; i < len; i++) {
reftable_log_record_release(&out[i]);
}
reftable_free(out);
for (i = 0; i < 3; i++) {
strbuf_release(&bufs[i]);
}
readers_destroy(readers, 3);
reftable_merged_table_free(mt);
reftable_free(bs);
}
static void test_default_write_opts(void)
{
struct reftable_write_options opts = { 0 };
struct strbuf buf = STRBUF_INIT;
struct reftable_writer *w =
reftable_new_writer(&strbuf_add_void, &buf, &opts);
struct reftable_ref_record rec = {
.refname = "master",
.update_index = 1,
};
int err;
struct reftable_block_source source = { NULL };
struct reftable_table *tab = reftable_calloc(sizeof(*tab) * 1);
uint32_t hash_id;
struct reftable_reader *rd = NULL;
struct reftable_merged_table *merged = NULL;
reftable_writer_set_limits(w, 1, 1);
err = reftable_writer_add_ref(w, &rec);
EXPECT_ERR(err);
err = reftable_writer_close(w);
EXPECT_ERR(err);
reftable_writer_free(w);
block_source_from_strbuf(&source, &buf);
err = reftable_new_reader(&rd, &source, "filename");
EXPECT_ERR(err);
hash_id = reftable_reader_hash_id(rd);
EXPECT(hash_id == GIT_SHA1_FORMAT_ID);
reftable_table_from_reader(&tab[0], rd);
err = reftable_new_merged_table(&merged, tab, 1, GIT_SHA1_FORMAT_ID);
EXPECT_ERR(err);
reftable_reader_free(rd);
reftable_merged_table_free(merged);
strbuf_release(&buf);
}
/* XXX test refs_for(oid) */
int merged_test_main(int argc, const char *argv[])
{
RUN_TEST(test_merged_logs);
RUN_TEST(test_merged_between);
RUN_TEST(test_merged);
RUN_TEST(test_default_write_opts);
return 0;
}

72
reftable/reftable-merged.h Normal file
View File

@ -0,0 +1,72 @@
/*
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
*/
#ifndef REFTABLE_MERGED_H
#define REFTABLE_MERGED_H
#include "reftable-iterator.h"
/*
* Merged tables
*
* A ref database kept in a sequence of table files. The merged_table presents a
* unified view to reading (seeking, iterating) a sequence of immutable tables.
*
* The merged tables are on purpose kept disconnected from their actual storage
* (eg. files on disk), because it is useful to merge tables aren't files. For
* example, the per-workspace and global ref namespace can be implemented as a
* merged table of two stacks of file-backed reftables.
*/
/* A merged table is implements seeking/iterating over a stack of tables. */
struct reftable_merged_table;
/* A generic reftable; see below. */
struct reftable_table;
/* reftable_new_merged_table creates a new merged table. It takes ownership of
the stack array.
*/
int reftable_new_merged_table(struct reftable_merged_table **dest,
struct reftable_table *stack, int n,
uint32_t hash_id);
/* returns an iterator positioned just before 'name' */
int reftable_merged_table_seek_ref(struct reftable_merged_table *mt,
struct reftable_iterator *it,
const char *name);
/* returns an iterator for log entry, at given update_index */
int reftable_merged_table_seek_log_at(struct reftable_merged_table *mt,
struct reftable_iterator *it,
const char *name, uint64_t update_index);
/* like reftable_merged_table_seek_log_at but look for the newest entry. */
int reftable_merged_table_seek_log(struct reftable_merged_table *mt,
struct reftable_iterator *it,
const char *name);
/* returns the max update_index covered by this merged table. */
uint64_t
reftable_merged_table_max_update_index(struct reftable_merged_table *mt);
/* returns the min update_index covered by this merged table. */
uint64_t
reftable_merged_table_min_update_index(struct reftable_merged_table *mt);
/* releases memory for the merged_table */
void reftable_merged_table_free(struct reftable_merged_table *m);
/* return the hash ID of the merged table. */
uint32_t reftable_merged_table_hash_id(struct reftable_merged_table *m);
/* create a generic table from reftable_merged_table */
void reftable_table_from_merged_table(struct reftable_table *tab,
struct reftable_merged_table *table);
#endif

1
t/helper/test-reftable.c
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@ -5,6 +5,7 @@ int cmd__reftable(int argc, const char **argv)
{ {
basics_test_main(argc, argv); basics_test_main(argc, argv);
block_test_main(argc, argv); block_test_main(argc, argv);
merged_test_main(argc, argv);
pq_test_main(argc, argv); pq_test_main(argc, argv);
record_test_main(argc, argv); record_test_main(argc, argv);
readwrite_test_main(argc, argv); readwrite_test_main(argc, argv);