Expose Cache::DisownData in C API (#8160)

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/8160

Reviewed By: riversand963

Differential Revision: D27672474

Pulled By: ajkr

fbshipit-source-id: fdbbc3398f0b1d4cef6b68636e5caf369c34b3a7

db/c.cc

@@ -4112,6 +4112,10 @@ void rocksdb_cache_destroy(rocksdb_cache_t* cache) {
   delete cache;
 }
 
+void rocksdb_cache_disown_data(rocksdb_cache_t* cache) {
+  cache->rep->DisownData();
+}
+
 void rocksdb_cache_set_capacity(rocksdb_cache_t* cache, size_t capacity) {
   cache->rep->SetCapacity(capacity);
 }

db/c_test.c

@@ -2869,6 +2869,7 @@ int main(int argc, char** argv) {
   rocksdb_readoptions_destroy(roptions);
   rocksdb_writeoptions_destroy(woptions);
   rocksdb_compactoptions_destroy(coptions);
+  rocksdb_cache_disown_data(cache);
   rocksdb_cache_destroy(cache);
   rocksdb_comparator_destroy(cmp);
   rocksdb_dbpath_destroy(dbpath);

include/rocksdb/c.h

@@ -1712,6 +1712,8 @@ extern ROCKSDB_LIBRARY_API unsigned char rocksdb_flushoptions_get_wait(
 extern ROCKSDB_LIBRARY_API rocksdb_cache_t* rocksdb_cache_create_lru(
     size_t capacity);
 extern ROCKSDB_LIBRARY_API void rocksdb_cache_destroy(rocksdb_cache_t* cache);
+extern ROCKSDB_LIBRARY_API void rocksdb_cache_disown_data(
+    rocksdb_cache_t* cache);
 extern ROCKSDB_LIBRARY_API void rocksdb_cache_set_capacity(
     rocksdb_cache_t* cache, size_t capacity);
 extern ROCKSDB_LIBRARY_API size_t