[pbs-devel] [PATCH proxmox-backup] data_blob: add TODO comment for zstd api

[Dominik Csapak]

we currently use the behavior of zstd that is not part of the public
api, so this is at risk to be changed without notice.

There is a public api that we could use, but it's only available
with zstd_sys >= 2.0.9, which at this time, is not yet packaged for/by
us.

Add a comment that we can use the public api for this when the
new version of the crate gets available.

Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
---
after looking whom to report that the api would benefit from better
error handling, i noticed that zstd_sys already has what we need, but
only in a newer version, which we currently don't package

 pbs-datastore/src/data_blob.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pbs-datastore/src/data_blob.rs b/pbs-datastore/src/data_blob.rs
index fd84f4be..0fb4d44c 100644
--- a/pbs-datastore/src/data_blob.rs
+++ b/pbs-datastore/src/data_blob.rs
@@ -556,6 +556,8 @@ impl<'a, 'b> DataChunkBuilder<'a, 'b> {
 ///
 /// There is a test below to ensure we catch any change in the interface or internal value.
 fn zstd_error_is_target_too_small(err: usize) -> bool {
+    // TODO: when zstd_sys >= 2.0.9 is available, we can use
+    // ZSTD_getErrorCode and the enum to use the public zstd API
     let (real_code, _) = 0usize.overflowing_sub(err);
     // see ZSTD_ErrorCode in https://github.com/facebook/zstd/blob/dev/lib/zstd_errors.h
     real_code == 70 // ZSTD_error_dstSize_tooSmall
-- 
2.39.2