Add piping API to buffered writer

This commit is contained in:
Yinan Zhang 2020-03-20 13:47:09 -07:00
parent 09cd79495f
commit f9aad7a49b
3 changed files with 106 additions and 1 deletions

View File

@ -27,4 +27,8 @@ void buf_writer_flush(buf_writer_t *buf_writer);
write_cb_t buf_writer_cb;
void buf_writer_terminate(tsdn_t *tsdn, buf_writer_t *buf_writer);
typedef ssize_t (read_cb_t)(void *read_cbopaque, void *buf, size_t limit);
void buf_writer_pipe(buf_writer_t *buf_writer, read_cb_t *read_cb,
void *read_cbopaque);
#endif /* JEMALLOC_INTERNAL_BUF_WRITER_H */

View File

@ -110,3 +110,36 @@ buf_writer_terminate(tsdn_t *tsdn, buf_writer_t *buf_writer) {
buf_writer_free_internal_buf(tsdn, buf_writer->buf);
}
}
void
buf_writer_pipe(buf_writer_t *buf_writer, read_cb_t *read_cb,
void *read_cbopaque) {
/*
* A tiny local buffer in case the buffered writer failed to allocate
* at init.
*/
static char backup_buf[16];
static buf_writer_t backup_buf_writer;
buf_writer_assert(buf_writer);
assert(read_cb != NULL);
if (buf_writer->buf == NULL) {
buf_writer_init(TSDN_NULL, &backup_buf_writer,
buf_writer->write_cb, buf_writer->cbopaque, backup_buf,
sizeof(backup_buf));
buf_writer = &backup_buf_writer;
}
assert(buf_writer->buf != NULL);
ssize_t nread = 0;
do {
buf_writer->buf_end += nread;
buf_writer_assert(buf_writer);
if (buf_writer->buf_end == buf_writer->buf_size) {
buf_writer_flush(buf_writer);
}
nread = read_cb(read_cbopaque,
buf_writer->buf + buf_writer->buf_end,
buf_writer->buf_size - buf_writer->buf_end);
} while (nread > 0);
buf_writer_flush(buf_writer);
}

View File

@ -119,10 +119,78 @@ TEST_BEGIN(test_buf_write_oom) {
}
TEST_END
static int test_read_count;
static size_t test_read_len;
static uint64_t arg_sum;
ssize_t
test_read_cb(void *cbopaque, void *buf, size_t limit) {
static uint64_t rand = 4;
arg_sum += *(uint64_t *)cbopaque;
assert_zu_gt(limit, 0, "Limit for read_cb must be positive");
--test_read_count;
if (test_read_count == 0) {
return -1;
} else {
size_t read_len = limit;
if (limit > 1) {
rand = prng_range_u64(&rand, (uint64_t)limit);
read_len -= (size_t)rand;
}
assert(read_len > 0);
memset(buf, 'a', read_len);
size_t prev_test_read_len = test_read_len;
test_read_len += read_len;
assert_zu_le(prev_test_read_len, test_read_len,
"Test read overflowed");
return read_len;
}
}
static void
test_buf_writer_pipe_body(tsdn_t *tsdn, buf_writer_t *buf_writer) {
arg = 4; /* Starting value of random argument. */
for (int count = 5; count > 0; --count) {
arg = prng_lg_range_u64(&arg, 64);
arg_sum = 0;
test_read_count = count;
test_read_len = 0;
test_write_len = 0;
buf_writer_pipe(buf_writer, test_read_cb, &arg);
assert(test_read_count == 0);
expect_u64_eq(arg_sum, arg * count, "");
expect_zu_eq(test_write_len, test_read_len,
"Write length should be equal to read length");
}
buf_writer_terminate(tsdn, buf_writer);
}
TEST_BEGIN(test_buf_write_pipe) {
buf_writer_t buf_writer;
tsdn_t *tsdn = tsdn_fetch();
assert_false(buf_writer_init(tsdn, &buf_writer, test_write_cb, &arg,
test_buf, TEST_BUF_SIZE),
"buf_writer_init() should not encounter error on static buffer");
test_buf_writer_pipe_body(tsdn, &buf_writer);
}
TEST_END
TEST_BEGIN(test_buf_write_pipe_oom) {
buf_writer_t buf_writer;
tsdn_t *tsdn = tsdn_fetch();
assert_true(buf_writer_init(tsdn, &buf_writer, test_write_cb, &arg,
NULL, SC_LARGE_MAXCLASS + 1), "buf_writer_init() should OOM");
test_buf_writer_pipe_body(tsdn, &buf_writer);
}
TEST_END
int
main(void) {
return test(
test_buf_write_static,
test_buf_write_dynamic,
test_buf_write_oom);
test_buf_write_oom,
test_buf_write_pipe,
test_buf_write_pipe_oom);
}