rocksdb: add supported_compression function (#88)

librocksdb_sys/crocksdb/c.cc

@@ -2947,6 +2947,18 @@ const char* crocksdb_pinnableslice_value(const crocksdb_pinnableslice_t* v,
   return v->rep.data();
 }
 
+size_t crocksdb_get_supported_compression_number() {
+  return rocksdb::GetSupportedCompressions().size();
+}
+
+void crocksdb_get_supported_compression(int* v, size_t l) {
+  auto compressions = rocksdb::GetSupportedCompressions();
+  assert(compressions.size() == l);
+  for (size_t i = 0; i < compressions.size(); i++) {
+    v[i] = static_cast<int>(compressions[i]);
+  }
+}
+
 /* Table Properties */
 
 struct crocksdb_user_collected_properties_t {

librocksdb_sys/crocksdb/rocksdb/c.h

@@ -1218,6 +1218,9 @@ extern C_ROCKSDB_LIBRARY_API void crocksdb_pinnableslice_destroy(
 extern C_ROCKSDB_LIBRARY_API const char* crocksdb_pinnableslice_value(
     const crocksdb_pinnableslice_t* t, size_t* vlen);
 
+extern C_ROCKSDB_LIBRARY_API size_t crocksdb_get_supported_compression_number();
+extern C_ROCKSDB_LIBRARY_API void crocksdb_get_supported_compression(int *, size_t);
+
 /* Table Properties */
 
 extern C_ROCKSDB_LIBRARY_API crocksdb_table_properties_t*

librocksdb_sys/src/lib.rs

@@ -82,6 +82,7 @@ pub enum DBCompressionType {
     DBLz4hc = 5,
     // DBXpress = 6, not support currently.
     DBZstd = 7,
+    DBZstdNotFinal = 0x40,
 }
 
 #[repr(C)]
@@ -852,6 +853,8 @@ extern "C" {
                                         valLen: *mut size_t)
                                         -> *const u8;
     pub fn crocksdb_pinnableslice_destroy(v: *mut DBPinnableSlice);
+    pub fn crocksdb_get_supported_compression_number() -> size_t;
+    pub fn crocksdb_get_supported_compression(v: *mut DBCompressionType, l: size_t);
 
     pub fn crocksdb_user_collected_properties_add(props: *mut DBUserCollectedProperties,
                                                   key: *const uint8_t,

src/rocksdb.rs

@@ -14,7 +14,8 @@
 //
 
 use crocksdb_ffi::{self, DBWriteBatch, DBCFHandle, DBInstance, DBBackupEngine,
-                   DBStatisticsTickerType, DBStatisticsHistogramType, DBPinnableSlice};
+                   DBStatisticsTickerType, DBStatisticsHistogramType, DBPinnableSlice,
+                   DBCompressionType};
 use libc::{self, c_int, c_void, size_t};
 use rocksdb_options::{Options, ReadOptions, UnsafeSnap, WriteOptions, FlushOptions, EnvOptions,
                       RestoreOptions, IngestExternalFileOptions, HistogramData, CompactOptions};
@@ -1459,6 +1460,17 @@ impl Drop for SstFileWriter {
     }
 }
 
+pub fn supported_compression() -> Vec<DBCompressionType> {
+    unsafe {
+        let size = crocksdb_ffi::crocksdb_get_supported_compression_number() as usize;
+        let mut v: Vec<DBCompressionType> = Vec::with_capacity(size);
+        let pv = v.as_mut_ptr();
+        crocksdb_ffi::crocksdb_get_supported_compression(pv, size as size_t);
+        v.set_len(size);
+        v
+    }
+}
+
 #[cfg(test)]
 mod test {
     use std::fs;
@@ -1889,4 +1901,21 @@ mod test {
             .unwrap();
         assert!(total_sst_files_size > 0);
     }
+
+    #[test]
+    fn test_supported_compression() {
+        let mut com = supported_compression();
+        let len_before = com.len();
+        assert!(com.len() != 0);
+        com.dedup();
+        assert_eq!(len_before, com.len());
+        for c in com {
+            println!("{:?}", c);
+            println!("{}", c as u32);
+            match c as u32 {
+                0...5 | 7 | 0x40 => assert!(true),
+                _ => assert!(false),
+            }
+        }
+    }
 }