reftable: stop using `strbuf_addf()`

We're about to introduce our own `reftable_buf` type to replace
`strbuf`. One function we'll have to convert is `strbuf_addf()`, which
is used in a handful of places. This function uses `snprintf()`
internally, which makes porting it a bit more involved:

  - It is not available on all platforms.

  - Some platforms like Windows have broken implementations.

So by using `snprintf()` we'd also push the burden on downstream users
of the reftable library to make available a properly working version of
it.

Most callsites of `strbuf_addf()` are trivial to convert to not using
it. We do end up using `snprintf()` in our unit tests, but that isn't
much of a problem for downstream users of the reftable library.

While at it, remove a useless call to `strbuf_reset()` in
`t_reftable_stack_auto_compaction_with_locked_tables()`. We don't write
to the buffer before this and initialize it with `STRBUF_INIT`, so there
is no need to reset anything.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Taylor Blau <me@ttaylorr.com>

1 files changed, 24 insertions, 18 deletions

diff --git a/t/unit-tests/t-reftable-stack.c b/t/unit-tests/t-reftable-stack.c
index 874095b9ee..b56ea77431 100644
--- a/t/unit-tests/t-reftable-stack.c
+++ b/t/unit-tests/t-reftable-stack.c
@@ -105,7 +105,6 @@ static int write_test_ref(struct reftable_writer *wr, void *arg)
 static void write_n_ref_tables(struct reftable_stack *st,
 			       size_t n)
 {
-	struct strbuf buf = STRBUF_INIT;
 	int disable_auto_compact;
 	int err;
 
@@ -117,10 +116,10 @@ static void write_n_ref_tables(struct reftable_stack *st,
 			.update_index = reftable_stack_next_update_index(st),
 			.value_type = REFTABLE_REF_VAL1,
 		};
+		char buf[128];
 
-		strbuf_reset(&buf);
-		strbuf_addf(&buf, "refs/heads/branch-%04"PRIuMAX, (uintmax_t)i);
-		ref.refname = buf.buf;
+		snprintf(buf, sizeof(buf), "refs/heads/branch-%04"PRIuMAX, (uintmax_t)i);
+		ref.refname = buf;
 		t_reftable_set_hash(ref.value.val1, i, GIT_SHA1_FORMAT_ID);
 
 		err = reftable_stack_add(st, &write_test_ref, &ref);
@@ -128,7 +127,6 @@ static void write_n_ref_tables(struct reftable_stack *st,
 	}
 
 	st->opts.disable_auto_compact = disable_auto_compact;
-	strbuf_release(&buf);
 }
 
 struct write_log_arg {
@@ -434,7 +432,10 @@ static void t_reftable_stack_auto_compaction_fails_gracefully(void)
 	 * Adding a new table to the stack should not be impacted by this, even
 	 * though auto-compaction will now fail.
 	 */
-	strbuf_addf(&table_path, "%s/%s.lock", dir, st->readers[0]->name);
+	strbuf_addstr(&table_path, dir);
+	strbuf_addstr(&table_path, "/");
+	strbuf_addstr(&table_path, st->readers[0]->name);
+	strbuf_addstr(&table_path, ".lock");
 	write_file_buf(table_path.buf, "", 0);
 
 	ref.update_index = 2;
@@ -1077,8 +1078,10 @@ static void t_reftable_stack_auto_compaction_with_locked_tables(void)
 	 * size, we expect that auto-compaction will want to compact all of the
 	 * tables. Locking any of the tables will keep it from doing so.
 	 */
-	strbuf_reset(&buf);
-	strbuf_addf(&buf, "%s/%s.lock", dir, st->readers[2]->name);
+	strbuf_addstr(&buf, dir);
+	strbuf_addstr(&buf, "/");
+	strbuf_addstr(&buf, st->readers[2]->name);
+	strbuf_addstr(&buf, ".lock");
 	write_file_buf(buf.buf, "", 0);
 
 	/*
@@ -1101,7 +1104,6 @@ static void t_reftable_stack_add_performs_auto_compaction(void)
 {
 	struct reftable_write_options opts = { 0 };
 	struct reftable_stack *st = NULL;
-	struct strbuf refname = STRBUF_INIT;
 	char *dir = get_tmp_dir(__LINE__);
 	int err;
 	size_t i, n = 20;
@@ -1115,6 +1117,7 @@ static void t_reftable_stack_add_performs_auto_compaction(void)
 			.value_type = REFTABLE_REF_SYMREF,
 			.value.symref = (char *) "master",
 		};
+		char buf[128];
 
 		/*
 		 * Disable auto-compaction for all but the last runs. Like this
@@ -1123,9 +1126,8 @@ static void t_reftable_stack_add_performs_auto_compaction(void)
 		 */
 		st->opts.disable_auto_compact = i != n;
 
-		strbuf_reset(&refname);
-		strbuf_addf(&refname, "branch-%04"PRIuMAX, (uintmax_t)i);
-		ref.refname = refname.buf;
+		snprintf(buf, sizeof(buf), "branch-%04"PRIuMAX, (uintmax_t)i);
+		ref.refname = buf;
 
 		err = reftable_stack_add(st, write_test_ref, &ref);
 		check(!err);
@@ -1142,7 +1144,6 @@ static void t_reftable_stack_add_performs_auto_compaction(void)
 	}
 
 	reftable_stack_destroy(st);
-	strbuf_release(&refname);
 	clear_dir(dir);
 }
 
@@ -1163,8 +1164,10 @@ static void t_reftable_stack_compaction_with_locked_tables(void)
 	check_int(st->merged->readers_len, ==, 3);
 
 	/* Lock one of the tables that we're about to compact. */
-	strbuf_reset(&buf);
-	strbuf_addf(&buf, "%s/%s.lock", dir, st->readers[1]->name);
+	strbuf_addstr(&buf, dir);
+	strbuf_addstr(&buf, "/");
+	strbuf_addstr(&buf, st->readers[1]->name);
+	strbuf_addstr(&buf, ".lock");
 	write_file_buf(buf.buf, "", 0);
 
 	/*
@@ -1321,10 +1324,13 @@ static void t_reftable_stack_reload_with_missing_table(void)
 	 * our old readers. This should trigger a partial reload of the stack,
 	 * where we try to reuse our old readers.
 	*/
-	strbuf_addf(&content, "%s\n", st->readers[0]->name);
-	strbuf_addf(&content, "%s\n", st->readers[1]->name);
+	strbuf_addstr(&content, st->readers[0]->name);
+	strbuf_addstr(&content, "\n");
+	strbuf_addstr(&content, st->readers[1]->name);
+	strbuf_addstr(&content, "\n");
 	strbuf_addstr(&content, "garbage\n");
-	strbuf_addf(&table_path, "%s.lock", st->list_file);
+	strbuf_addstr(&table_path, st->list_file);
+	strbuf_addstr(&table_path, ".lock");
 	write_file_buf(table_path.buf, content.buf, content.len);
 	err = rename(table_path.buf, st->list_file);
 	check(!err);