add rocksdb log dir option (#61)

librocksdb_sys/src/lib.rs

@@ -189,6 +189,7 @@ extern "C" {
     pub fn rocksdb_options_statistics_get_string(options: *mut DBOptions) -> *const c_char;
     pub fn rocksdb_options_set_stats_dump_period_sec(options: *mut DBOptions, v: usize);
     pub fn rocksdb_options_set_num_levels(options: *mut DBOptions, v: c_int);
+    pub fn rocksdb_options_set_db_log_dir(options: *mut DBOptions, path: *const c_char);
     pub fn rocksdb_filterpolicy_create_bloom_full(bits_per_key: c_int) -> *mut DBFilterPolicy;
     pub fn rocksdb_filterpolicy_create_bloom(bits_per_key: c_int) -> *mut DBFilterPolicy;
     pub fn rocksdb_open(options: *mut DBOptions,

src/rocksdb.rs

@@ -1043,6 +1043,8 @@ impl Drop for BackupEngine {
 #[cfg(test)]
 mod test {
     use rocksdb_options::*;
+    use std::fs;
+    use std::path::Path;
     use std::str;
     use super::*;
     use tempdir::TempDir;
@@ -1218,6 +1220,32 @@ mod test {
             assert!(r.unwrap().unwrap().to_utf8().unwrap() == str::from_utf8(value).unwrap());
         }
     }
+
+    #[test]
+    fn log_dir_test() {
+        let db_dir = TempDir::new("_rust_rocksdb_logdirtest").unwrap();
+        let db_path = db_dir.path().to_str().unwrap();
+        let log_path = format!("{}", Path::new(&db_path).join("log_path").display());
+        fs::create_dir_all(&log_path).unwrap();
+
+        let mut opts = Options::new();
+        opts.create_if_missing(true);
+        opts.set_db_log_dir(&log_path);
+
+        DB::open(opts, db_path).unwrap();
+
+        // Check LOG file.
+        let mut read_dir = fs::read_dir(&log_path).unwrap();
+        let entry = read_dir.next().unwrap().unwrap();
+        let name = entry.file_name();
+        name.to_str().unwrap().find("LOG").unwrap();
+
+        for entry in fs::read_dir(&db_path).unwrap() {
+            let entry = entry.unwrap();
+            let name = entry.file_name();
+            assert!(name.to_str().unwrap().find("LOG").is_none());
+        }
+    }
 }
 
 #[test]

src/rocksdb_options.rs

@@ -549,6 +549,13 @@ impl Options {
             rocksdb_ffi::rocksdb_options_set_num_levels(self.inner, n);
         }
     }
+
+    pub fn set_db_log_dir(&mut self, path: &str) {
+        let path = CString::new(path.as_bytes()).unwrap();
+        unsafe {
+            rocksdb_ffi::rocksdb_options_set_db_log_dir(self.inner, path.as_ptr());
+        }
+    }
 }
 
 pub struct FlushOptions {