Add API entry-point for getting compression method version numbers.

This patch adds `tor_compress_version_str()` and
`tor_compress_header_version_str()` to get the version strings of the
different compression schema providers. Both functions returns `NULL` in
case a given `compress_method_t` is unknown or unsupported.

See: https://bugs.torproject.org/21662

1 files changed, 4 insertions, 4 deletions

diff --git a/src/common/compress_zstd.c b/src/common/compress_zstd.c
index dca4dbdab5..c838cd9364 100644
--- a/src/common/compress_zstd.c
+++ b/src/common/compress_zstd.c
@@ -38,7 +38,7 @@ tor_zstd_method_supported(void)
 }
 
 /** Return a string representation of the version of the currently running
- * version of libzstd. */
+ * version of libzstd. Returns NULL if Zstandard is unsupported. */
 const char *
 tor_zstd_get_version_str(void)
 {
@@ -55,19 +55,19 @@ tor_zstd_get_version_str(void)
 
   return version_str;
 #else
-  return "N/A";
+  return NULL;
 #endif
 }
 
 /** Return a string representation of the version of the version of libzstd
- * used at compilation. */
+ * used at compilation time. Returns NULL if Zstandard is unsupported. */
 const char *
 tor_zstd_get_header_version_str(void)
 {
 #ifdef HAVE_ZSTD
   return ZSTD_VERSION_STRING;
 #else
-  return "N/A";
+  return NULL;
 #endif
 }