Add create_missing_column_families option (#573)

Add create_missing_column_families for DBOptions, so we can open a database with added column families.

Close #362.
Signed-off-by: Peilun Li <peilun.li@conflux-chain.org>

librocksdb_sys/src/lib.rs

@@ -646,6 +646,7 @@ extern "C" {
         filter: *mut DBCompactionFilterFactory,
     );
     pub fn crocksdb_options_set_create_if_missing(options: *mut Options, v: bool);
+    pub fn crocksdb_options_set_create_missing_column_families(options: *mut Options, v: bool);
     pub fn crocksdb_options_set_max_open_files(options: *mut Options, files: c_int);
     pub fn crocksdb_options_set_max_total_wal_size(options: *mut Options, size: u64);
     pub fn crocksdb_options_set_use_fsync(options: *mut Options, v: c_int);

src/rocksdb_options.rs

@@ -738,6 +738,15 @@ impl DBOptions {
         }
     }
 
+    pub fn create_missing_column_families(&mut self, create_missing_column_families: bool) {
+        unsafe {
+            crocksdb_ffi::crocksdb_options_set_create_missing_column_families(
+                self.inner,
+                create_missing_column_families,
+            )
+        }
+    }
+
     pub fn set_env(&mut self, env: Arc<Env>) {
         unsafe {
             crocksdb_ffi::crocksdb_options_set_env(self.inner, env.inner);