Support self-defined base env for encrypted env (#254)

* Support encrypted env

* Support encrypted env

* Add tests

* guard base env

* guard base env

* guard base env

librocksdb_sys/crocksdb/c.cc

@@ -3282,15 +3282,16 @@ struct CTRBlockCipher : public BlockCipher {
   size_t block_size_;
 };
 
-crocksdb_env_t* crocksdb_default_ctr_encrypted_env_create(
+crocksdb_env_t*
+crocksdb_ctr_encrypted_env_create(crocksdb_env_t* base_env,
     const char* ciphertext, size_t ciphertext_len) {
   auto result = new crocksdb_env_t;
   result->block_cipher = new CTRBlockCipher(
       ciphertext_len, std::string(ciphertext, ciphertext_len));
   result->encryption_provoider =
       new CTREncryptionProvider(*result->block_cipher);
-  result->rep = NewEncryptedEnv(Env::Default(), result->encryption_provoider);
-  result->is_default = true;
+  result->rep = NewEncryptedEnv(base_env->rep, result->encryption_provoider);
+  result->is_default = false;
 
   return result;
 }

librocksdb_sys/crocksdb/crocksdb/c.h

@@ -1309,7 +1309,8 @@ extern C_ROCKSDB_LIBRARY_API void crocksdb_cache_set_capacity(
 extern C_ROCKSDB_LIBRARY_API crocksdb_env_t* crocksdb_default_env_create();
 extern C_ROCKSDB_LIBRARY_API crocksdb_env_t* crocksdb_mem_env_create();
 extern C_ROCKSDB_LIBRARY_API crocksdb_env_t*
-crocksdb_default_ctr_encrypted_env_create(const char* ciphertext,
+crocksdb_ctr_encrypted_env_create(crocksdb_env_t* base_env,
+                                  const char* ciphertext,
                                   size_t ciphertext_len);
 extern C_ROCKSDB_LIBRARY_API void crocksdb_env_set_background_threads(
     crocksdb_env_t* env, int n);

librocksdb_sys/src/lib.rs

@@ -1128,7 +1128,8 @@ extern "C" {
     // Env
     pub fn crocksdb_default_env_create() -> *mut DBEnv;
     pub fn crocksdb_mem_env_create() -> *mut DBEnv;
-    pub fn crocksdb_default_ctr_encrypted_env_create(
+    pub fn crocksdb_ctr_encrypted_env_create(
+        base_env: *mut DBEnv,
         ciphertext: *const c_char,
         ciphertext_len: size_t,
     ) -> *mut DBEnv;

src/rocksdb.rs

@@ -1664,7 +1664,10 @@ impl Drop for DB {
     fn drop(&mut self) {
         // SyncWAL before call close.
         if !self.readonly {
-            self.sync_wal().unwrap();
+            // DB::SyncWal requires writable file support thread safe sync, but
+            // not all types of env can create writable file that support thread
+            // safe sync. eg, MemEnv.
+            self.sync_wal().unwrap_or_else(|_| {});
         }
         unsafe {
             self.cfs.clear();
@@ -2082,6 +2085,8 @@ pub fn supported_compression() -> Vec<DBCompressionType> {
 
 pub struct Env {
     pub inner: *mut DBEnv,
+    #[allow(dead_code)]
+    base: Option<Arc<Env>>,
 }
 
 unsafe impl Send for Env {}
@@ -2093,6 +2098,7 @@ impl Default for Env {
         unsafe {
             Env {
                 inner: crocksdb_ffi::crocksdb_default_env_create(),
+                base: None,
             }
         }
     }
@@ -2103,14 +2109,15 @@ impl Env {
         unsafe {
             Env {
                 inner: crocksdb_ffi::crocksdb_mem_env_create(),
+                base: None,
             }
         }
     }
 
-    // Create a ctr encrypted env with the default env and a given ciper text.
+    // Create a ctr encrypted env with a given base env and a given ciper text.
     // The length of ciper text must be 2^n, and must be less or equal to 2048.
     // The recommanded block size are 1024, 512 and 256.
-    pub fn new_default_ctr_encrypted_env(ciphertext: &[u8]) -> Result<Env, String> {
+    pub fn new_ctr_encrypted_env(base_env: Arc<Env>, ciphertext: &[u8]) -> Result<Env, String> {
         let len = ciphertext.len();
         if len > 2048 || !is_power_of_two(len) {
             return Err(
@@ -2119,12 +2126,21 @@ impl Env {
             );
         }
         let env = unsafe {
-            crocksdb_ffi::crocksdb_default_ctr_encrypted_env_create(
+            crocksdb_ffi::crocksdb_ctr_encrypted_env_create(
+                base_env.inner,
                 mem::transmute(&ciphertext[0]),
                 len,
             )
         };
-        Ok(Env { inner: env })
+        Ok(Env {
+            inner: env,
+            base: Some(base_env),
+        })
+    }
+
+    // Create a ctr encrypted env with the default env
+    pub fn new_default_ctr_encrypted_env(ciphertext: &[u8]) -> Result<Env, String> {
+        Env::new_ctr_encrypted_env(Arc::new(Env::default()), ciphertext)
     }
 
     pub fn new_sequential_file(

tests/cases/test_encryption.rs

@@ -22,6 +22,12 @@ fn test_ctr_encrypted_env() {
         &[16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1],
         &[8, 7, 6, 5, 4, 3, 2, 1],
     ];
+    for ciphertext in test_cipher_texts {
+        let base_env = Arc::new(Env::new_mem());
+        test_ctr_encrypted_env_impl(Arc::new(
+            Env::new_ctr_encrypted_env(Arc::clone(&base_env), ciphertext).unwrap(),
+        ));
+    }
     for ciphertext in test_cipher_texts {
         test_ctr_encrypted_env_impl(Arc::new(
             Env::new_default_ctr_encrypted_env(ciphertext).unwrap(),