reftable: pass opts as constant pointer

We sometimes pass the refatble write options as value and sometimes as a
pointer. This is quite confusing and makes the reader wonder whether the
options get modified sometimes.

In fact, `reftable_new_writer()` does cause the caller-provided options
to get updated when some values aren't set up. This is quite unexpected,
but didn't cause any harm until now.

Adapt the code so that we do not modify the caller-provided values
anymore. While at it, refactor the code to code to consistently pass the
options as a constant pointer to clarify that the caller-provided opts
will not ever get modified.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index 010ef811b6484197912189edf8a4cf901262bf9c..f8f930380d6e41f809221278fbb1bc8b496ac64a 100644 (file)
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -129,7 +129,7 @@ static struct reftable_stack *stack_for(struct reftable_ref_store *store,
                                    store->base.repo->commondir, wtname_buf.buf);
 
                        store->err = reftable_new_stack(&stack, wt_dir.buf,
-                                                       store->write_options);
+                                                       &store->write_options);
                        assert(store->err != REFTABLE_API_ERROR);
                        strmap_put(&store->worktree_stacks, wtname_buf.buf, stack);
                }
@@ -263,7 +263,7 @@ static struct ref_store *reftable_be_init(struct repository *repo,
        }
        strbuf_addstr(&path, "/reftable");
        refs->err = reftable_new_stack(&refs->main_stack, path.buf,
-                                      refs->write_options);
+                                      &refs->write_options);
        if (refs->err)
                goto done;
 
@@ -280,7 +280,7 @@ static struct ref_store *reftable_be_init(struct repository *repo,
                strbuf_addf(&path, "%s/reftable", gitdir);
 
                refs->err = reftable_new_stack(&refs->worktree_stack, path.buf,
-                                              refs->write_options);
+                                              &refs->write_options);
                if (refs->err)
                        goto done;
        }

diff --git a/reftable/dump.c b/reftable/dump.c
index 9c770a10cc45b13f3ea261ee47944b066ec3f3cb..586f3eb2883b62e641aedf4aedf02081f8ae77f4 100644 (file)
--- a/reftable/dump.c
+++ b/reftable/dump.c
@@ -29,7 +29,7 @@ static int compact_stack(const char *stackdir)
        struct reftable_stack *stack = NULL;
        struct reftable_write_options opts = { 0 };
 
-       int err = reftable_new_stack(&stack, stackdir, opts);
+       int err = reftable_new_stack(&stack, stackdir, &opts);
        if (err < 0)
                goto done;
 

diff --git a/reftable/reftable-stack.h b/reftable/reftable-stack.h
index 9c8e4eef49609d8fc85b560ad29c9356c3c67133..c15632c401dbfdee0fb6a828a48427f8abb52ebb 100644 (file)
--- a/reftable/reftable-stack.h
+++ b/reftable/reftable-stack.h
@@ -29,7 +29,7 @@ struct reftable_stack;
  *  stored in 'dir'. Typically, this should be .git/reftables.
  */
 int reftable_new_stack(struct reftable_stack **dest, const char *dir,
-                      struct reftable_write_options opts);
+                      const struct reftable_write_options *opts);
 
 /* returns the update_index at which a next table should be written. */
 uint64_t reftable_stack_next_update_index(struct reftable_stack *st);

diff --git a/reftable/reftable-writer.h b/reftable/reftable-writer.h
index b601a69a40251788094d9f3e64e9b90445dc2654..03df3a4963248ea091fa5e207eb767869a7ad438 100644 (file)
--- a/reftable/reftable-writer.h
+++ b/reftable/reftable-writer.h
@@ -88,7 +88,7 @@ struct reftable_stats {
 struct reftable_writer *
 reftable_new_writer(ssize_t (*writer_func)(void *, const void *, size_t),
                    int (*flush_func)(void *),
-                   void *writer_arg, struct reftable_write_options *opts);
+                   void *writer_arg, const struct reftable_write_options *opts);
 
 /* Set the range of update indices for the records we will add. When writing a
    table into a stack, the min should be at least

diff --git a/reftable/stack.c b/reftable/stack.c
index 54e7473f3a01378cced629dcc32dbeb7f6a8621e..d2e68be7e867cc6b1acad758d45d27861072407a 100644 (file)
--- a/reftable/stack.c
+++ b/reftable/stack.c
@@ -54,12 +54,15 @@ static int reftable_fd_flush(void *arg)
 }
 
 int reftable_new_stack(struct reftable_stack **dest, const char *dir,
-                      struct reftable_write_options opts)
+                      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;
 
@@ -1438,7 +1441,7 @@ int reftable_stack_print_directory(const char *stackdir, uint32_t hash_id)
        struct reftable_merged_table *merged = NULL;
        struct reftable_table table = { NULL };
 
-       int err = reftable_new_stack(&stack, stackdir, opts);
+       int err = reftable_new_stack(&stack, stackdir, &opts);
        if (err < 0)
                goto done;
 

diff --git a/reftable/stack_test.c b/reftable/stack_test.c
index e17ad4dc62b448937d89d69b87c3c4a417f20a43..d15f11d712066fbdc1f675a87269fdb142d11bd2 100644 (file)
--- a/reftable/stack_test.c
+++ b/reftable/stack_test.c
@@ -163,7 +163,7 @@ static void test_reftable_stack_add_one(void)
        };
        struct reftable_ref_record dest = { NULL };
        struct stat stat_result = { 0 };
-       err = reftable_new_stack(&st, dir, opts);
+       err = reftable_new_stack(&st, dir, &opts);
        EXPECT_ERR(err);
 
        err = reftable_stack_add(st, &write_test_ref, &ref);
@@ -232,10 +232,10 @@ static void test_reftable_stack_uptodate(void)
        /* simulate multi-process access to the same stack
           by creating two stacks for the same directory.
         */
-       err = reftable_new_stack(&st1, dir, opts);
+       err = reftable_new_stack(&st1, dir, &opts);
        EXPECT_ERR(err);
 
-       err = reftable_new_stack(&st2, dir, opts);
+       err = reftable_new_stack(&st2, dir, &opts);
        EXPECT_ERR(err);
 
        err = reftable_stack_add(st1, &write_test_ref, &ref1);
@@ -270,7 +270,7 @@ static void test_reftable_stack_transaction_api(void)
        };
        struct reftable_ref_record dest = { NULL };
 
-       err = reftable_new_stack(&st, dir, opts);
+       err = reftable_new_stack(&st, dir, &opts);
        EXPECT_ERR(err);
 
        reftable_addition_destroy(add);
@@ -304,7 +304,7 @@ static void test_reftable_stack_transaction_api_performs_auto_compaction(void)
        struct reftable_stack *st = NULL;
        int i, n = 20, err;
 
-       err = reftable_new_stack(&st, dir, opts);
+       err = reftable_new_stack(&st, dir, &opts);
        EXPECT_ERR(err);
 
        for (i = 0; i <= n; i++) {
@@ -365,7 +365,7 @@ static void test_reftable_stack_auto_compaction_fails_gracefully(void)
        char *dir = get_tmp_dir(__LINE__);
        int err;
 
-       err = reftable_new_stack(&st, dir, opts);
+       err = reftable_new_stack(&st, dir, &opts);
        EXPECT_ERR(err);
 
        err = reftable_stack_add(st, write_test_ref, &ref);
@@ -418,7 +418,7 @@ static void test_reftable_stack_update_index_check(void)
                .value.symref = "master",
        };
 
-       err = reftable_new_stack(&st, dir, opts);
+       err = reftable_new_stack(&st, dir, &opts);
        EXPECT_ERR(err);
 
        err = reftable_stack_add(st, &write_test_ref, &ref1);
@@ -437,7 +437,7 @@ static void test_reftable_stack_lock_failure(void)
        struct reftable_stack *st = NULL;
        int err, i;
 
-       err = reftable_new_stack(&st, dir, opts);
+       err = reftable_new_stack(&st, dir, &opts);
        EXPECT_ERR(err);
        for (i = -1; i != REFTABLE_EMPTY_TABLE_ERROR; i--) {
                err = reftable_stack_add(st, &write_error, &i);
@@ -465,7 +465,7 @@ static void test_reftable_stack_add(void)
        struct stat stat_result;
        int N = ARRAY_SIZE(refs);
 
-       err = reftable_new_stack(&st, dir, opts);
+       err = reftable_new_stack(&st, dir, &opts);
        EXPECT_ERR(err);
 
        for (i = 0; i < N; i++) {
@@ -575,7 +575,7 @@ static void test_reftable_stack_log_normalize(void)
                .update_index = 1,
        };
 
-       err = reftable_new_stack(&st, dir, opts);
+       err = reftable_new_stack(&st, dir, &opts);
        EXPECT_ERR(err);
 
        input.value.update.message = "one\ntwo";
@@ -617,7 +617,7 @@ static void test_reftable_stack_tombstone(void)
        struct reftable_ref_record dest = { NULL };
        struct reftable_log_record log_dest = { NULL };
 
-       err = reftable_new_stack(&st, dir, opts);
+       err = reftable_new_stack(&st, dir, &opts);
        EXPECT_ERR(err);
 
        /* even entries add the refs, odd entries delete them. */
@@ -701,18 +701,18 @@ static void test_reftable_stack_hash_id(void)
        struct reftable_stack *st_default = NULL;
        struct reftable_ref_record dest = { NULL };
 
-       err = reftable_new_stack(&st, dir, opts);
+       err = reftable_new_stack(&st, dir, &opts);
        EXPECT_ERR(err);
 
        err = reftable_stack_add(st, &write_test_ref, &ref);
        EXPECT_ERR(err);
 
        /* can't read it with the wrong hash ID. */
-       err = reftable_new_stack(&st32, dir, opts32);
+       err = reftable_new_stack(&st32, dir, &opts32);
        EXPECT(err == REFTABLE_FORMAT_ERROR);
 
        /* check that we can read it back with default opts too. */
-       err = reftable_new_stack(&st_default, dir, opts_default);
+       err = reftable_new_stack(&st_default, dir, &opts_default);
        EXPECT_ERR(err);
 
        err = reftable_stack_read_ref(st_default, "master", &dest);
@@ -756,7 +756,7 @@ static void test_reflog_expire(void)
        };
        struct reftable_log_record log = { NULL };
 
-       err = reftable_new_stack(&st, dir, opts);
+       err = reftable_new_stack(&st, dir, &opts);
        EXPECT_ERR(err);
 
        for (i = 1; i <= N; i++) {
@@ -825,13 +825,13 @@ static void test_empty_add(void)
        char *dir = get_tmp_dir(__LINE__);
        struct reftable_stack *st2 = NULL;
 
-       err = reftable_new_stack(&st, dir, opts);
+       err = reftable_new_stack(&st, dir, &opts);
        EXPECT_ERR(err);
 
        err = reftable_stack_add(st, &write_nothing, NULL);
        EXPECT_ERR(err);
 
-       err = reftable_new_stack(&st2, dir, opts);
+       err = reftable_new_stack(&st2, dir, &opts);
        EXPECT_ERR(err);
        clear_dir(dir);
        reftable_stack_destroy(st);
@@ -858,7 +858,7 @@ static void test_reftable_stack_auto_compaction(void)
        int err, i;
        int N = 100;
 
-       err = reftable_new_stack(&st, dir, opts);
+       err = reftable_new_stack(&st, dir, &opts);
        EXPECT_ERR(err);
 
        for (i = 0; i < N; i++) {
@@ -894,7 +894,7 @@ static void test_reftable_stack_add_performs_auto_compaction(void)
        char *dir = get_tmp_dir(__LINE__);
        int err, i, n = 20;
 
-       err = reftable_new_stack(&st, dir, opts);
+       err = reftable_new_stack(&st, dir, &opts);
        EXPECT_ERR(err);
 
        for (i = 0; i <= n; i++) {
@@ -942,7 +942,7 @@ static void test_reftable_stack_compaction_concurrent(void)
        int err, i;
        int N = 3;
 
-       err = reftable_new_stack(&st1, dir, opts);
+       err = reftable_new_stack(&st1, dir, &opts);
        EXPECT_ERR(err);
 
        for (i = 0; i < N; i++) {
@@ -959,7 +959,7 @@ static void test_reftable_stack_compaction_concurrent(void)
                EXPECT_ERR(err);
        }
 
-       err = reftable_new_stack(&st2, dir, opts);
+       err = reftable_new_stack(&st2, dir, &opts);
        EXPECT_ERR(err);
 
        err = reftable_stack_compact_all(st1, NULL);
@@ -991,7 +991,7 @@ static void test_reftable_stack_compaction_concurrent_clean(void)
        int err, i;
        int N = 3;
 
-       err = reftable_new_stack(&st1, dir, opts);
+       err = reftable_new_stack(&st1, dir, &opts);
        EXPECT_ERR(err);
 
        for (i = 0; i < N; i++) {
@@ -1008,7 +1008,7 @@ static void test_reftable_stack_compaction_concurrent_clean(void)
                EXPECT_ERR(err);
        }
 
-       err = reftable_new_stack(&st2, dir, opts);
+       err = reftable_new_stack(&st2, dir, &opts);
        EXPECT_ERR(err);
 
        err = reftable_stack_compact_all(st1, NULL);
@@ -1017,7 +1017,7 @@ static void test_reftable_stack_compaction_concurrent_clean(void)
        unclean_stack_close(st1);
        unclean_stack_close(st2);
 
-       err = reftable_new_stack(&st3, dir, opts);
+       err = reftable_new_stack(&st3, dir, &opts);
        EXPECT_ERR(err);
 
        err = reftable_stack_clean(st3);

diff --git a/reftable/writer.c b/reftable/writer.c
index 10eccaaa07f568ecc78bcb58adc90429ad5393c7..4cc6e2ebd83017da3030390fa7c4da7dcf707607 100644 (file)
--- a/reftable/writer.c
+++ b/reftable/writer.c
@@ -122,20 +122,25 @@ static struct strbuf reftable_empty_strbuf = STRBUF_INIT;
 struct reftable_writer *
 reftable_new_writer(ssize_t (*writer_func)(void *, const void *, size_t),
                    int (*flush_func)(void *),
-                   void *writer_arg, struct reftable_write_options *opts)
+                   void *writer_arg, const struct reftable_write_options *_opts)
 {
        struct reftable_writer *wp = reftable_calloc(1, sizeof(*wp));
-       strbuf_init(&wp->block_writer_data.last_key, 0);
-       options_set_defaults(opts);
-       if (opts->block_size >= (1 << 24)) {
+       struct reftable_write_options opts = {0};
+
+       if (_opts)
+               opts = *_opts;
+       options_set_defaults(&opts);
+       if (opts.block_size >= (1 << 24)) {
                /* TODO - error return? */
                abort();
        }
+
+       strbuf_init(&wp->block_writer_data.last_key, 0);
        wp->last_key = reftable_empty_strbuf;
-       REFTABLE_CALLOC_ARRAY(wp->block, opts->block_size);
+       REFTABLE_CALLOC_ARRAY(wp->block, opts.block_size);
        wp->write = writer_func;
        wp->write_arg = writer_arg;
-       wp->opts = *opts;
+       wp->opts = opts;
        wp->flush = flush_func;
        writer_reinit_block_writer(wp, BLOCK_TYPE_REF);