Added basic support for backups.

librocksdb-sys/src/test.rs

@@ -41,11 +41,10 @@ fn internal() {
 
         let rustpath = "_rust_rocksdb_internaltest";
         let cpath = CString::new(rustpath).unwrap();
-        let cpath_ptr = cpath.as_ptr();
 
         let mut err: *mut c_char = ptr::null_mut();
         let err_ptr: *mut *mut c_char = &mut err;
-        let db = rocksdb_open(opts, cpath_ptr as *const _, err_ptr);
+        let db = rocksdb_open(opts, cpath.as_ptr() as *const _, err_ptr);
         if !err.is_null() {
             println!("failed to open rocksdb: {}", error_message(err));
         }
@@ -80,7 +79,7 @@ fn internal() {
         rocksdb_readoptions_destroy(readopts);
         assert!(err.is_null());
         rocksdb_close(db);
-        rocksdb_destroy_db(opts, cpath_ptr as *const _, err_ptr);
+        rocksdb_destroy_db(opts, cpath.as_ptr() as *const _, err_ptr);
         assert!(err.is_null());
     }
 }

src/backup.rs

@@ -0,0 +1,100 @@
+// Copyright 2016 Alex Regueiro
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+use std::ffi::CString;
+use std::path::{Path};
+
+use libc::{uint32_t};
+
+use {DB, Error};
+use ffi;
+
+pub struct BackupEngine {
+    inner: *mut ffi::rocksdb_backup_engine_t,
+}
+
+pub struct BackupEngineOptions {
+    inner: *mut ffi::rocksdb_options_t,
+}
+
+impl BackupEngine {
+    /// Open a backup engine with the specified options.
+    pub fn open<P: AsRef<Path>>(opts: &BackupEngineOptions, path: P) -> Result<BackupEngine, Error> {
+        let path = path.as_ref();
+        let cpath = match CString::new(path.to_string_lossy().as_bytes()) {
+            Ok(c) => c,
+            Err(_) => {
+                return Err(Error::new("Failed to convert path to CString \
+                                       when opening backup engine"
+                    .to_owned()))
+            }
+        };
+
+        let be: *mut ffi::rocksdb_backup_engine_t;
+        unsafe {
+            be = ffi_try!(ffi::rocksdb_backup_engine_open(opts.inner, cpath.as_ptr()))
+        }
+
+        if be.is_null() {
+            return Err(Error::new("Could not initialize backup engine.".to_owned()));
+        }
+
+        Ok(BackupEngine {
+            inner: be,
+        })
+    }
+
+    fn create_new_backup(&mut self, db: &DB) -> Result<(), Error> {
+        unsafe {
+            ffi_try!(ffi::rocksdb_backup_engine_create_new_backup(self.inner, db.inner));
+            Ok(())
+        }
+    }
+
+    fn purge_old_backups(&mut self, num_backups_to_keep: usize) -> Result<(), Error> {
+        unsafe {
+            ffi_try!(ffi::rocksdb_backup_engine_purge_old_backups(self.inner, num_backups_to_keep as uint32_t));
+            Ok(())
+        }
+    }
+}
+
+impl Default for BackupEngineOptions {
+    fn default() -> BackupEngineOptions {
+        unsafe {
+            let opts = ffi::rocksdb_options_create();
+            if opts.is_null() {
+                panic!("Could not create backup options".to_owned());
+            }
+            BackupEngineOptions { inner: opts }
+        }
+    }
+}
+
+impl Drop for BackupEngine {
+    fn drop(&mut self) {
+        unsafe {
+            ffi::rocksdb_backup_engine_close(self.inner);
+        }
+    }
+}
+
+impl Drop for BackupEngineOptions {
+    fn drop(&mut self) {
+        unsafe {
+            ffi::rocksdb_options_destroy(self.inner);
+        }
+    }
+}

src/lib.rs

@@ -37,15 +37,60 @@ extern crate librocksdb_sys as ffi;
 #[macro_use]
 mod ffi_util;
 
+pub mod backup;
 mod comparator;
 pub mod merge_operator;
 mod rocksdb;
 mod rocksdb_options;
 
-pub use rocksdb::{DB, DBCompactionStyle, DBCompressionType, DBIterator, DBRecoveryMode, DBVector,
-                  Direction, Error, IteratorMode, Snapshot, WriteBatch, new_bloom_filter};
+use std::collections::BTreeMap;
+use std::error;
+use std::fmt;
+use std::path::{PathBuf};
 
 pub use merge_operator::MergeOperands;
+pub use rocksdb::{DBCompactionStyle, DBCompressionType, DBIterator, DBRecoveryMode, DBVector,
+                  Direction, IteratorMode, Snapshot, WriteBatch, new_bloom_filter};
+
+/// A RocksDB database.
+pub struct DB {
+    inner: *mut ffi::rocksdb_t,
+    cfs: BTreeMap<String, *mut ffi::rocksdb_column_family_handle_t>,
+    path: PathBuf,
+}
+
+#[derive(Debug, PartialEq)]
+pub struct Error {
+    message: String,
+}
+
+impl Error {
+    fn new(message: String) -> Error {
+        Error { message: message }
+    }
+
+    pub fn to_string(self) -> String {
+        self.into()
+    }
+}
+
+impl From<Error> for String {
+    fn from(e: Error) -> String {
+        e.message
+    }
+}
+
+impl error::Error for Error {
+    fn description(&self) -> &str {
+        &self.message
+    }
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        self.message.fmt(formatter)
+    }
+}
 
 /// For configuring block-based file storage.
 pub struct BlockBasedOptions {

src/rocksdb.rs

@@ -14,19 +14,18 @@
 //
 
 use std::collections::BTreeMap;
-use std::error;
 use std::ffi::CString;
 use std::fmt;
 use std::fs;
 use std::ops::Deref;
-use std::path::{Path, PathBuf};
+use std::path::{Path};
 use std::ptr;
 use std::slice;
 use std::str;
 
 use libc::{self, c_char, c_int, c_uchar, c_void, size_t};
 
-use {Options, WriteOptions};
+use {DB, Error, Options, WriteOptions};
 use ffi;
 
 pub fn new_bloom_filter(bits: c_int) -> *mut ffi::rocksdb_filterpolicy_t {
@@ -37,13 +36,6 @@ pub fn new_cache(capacity: size_t) -> *mut ffi::rocksdb_cache_t {
     unsafe { ffi::rocksdb_cache_create_lru(capacity) }
 }
 
-/// A RocksDB database.
-pub struct DB {
-    inner: *mut ffi::rocksdb_t,
-    cfs: BTreeMap<String, *mut ffi::rocksdb_column_family_handle_t>,
-    path: PathBuf,
-}
-
 unsafe impl Send for DB {}
 unsafe impl Sync for DB {}
 
@@ -151,39 +143,6 @@ pub enum Direction {
 
 pub type KVBytes = (Box<[u8]>, Box<[u8]>);
 
-#[derive(Debug, PartialEq)]
-pub struct Error {
-    message: String,
-}
-
-impl Error {
-    fn new(message: String) -> Error {
-        Error { message: message }
-    }
-
-    pub fn to_string(self) -> String {
-        self.into()
-    }
-}
-
-impl From<Error> for String {
-    fn from(e: Error) -> String {
-        e.message
-    }
-}
-
-impl error::Error for Error {
-    fn description(&self) -> &str {
-        &self.message
-    }
-}
-
-impl fmt::Display for Error {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        self.message.fmt(formatter)
-    }
-}
-
 impl Iterator for DBIterator {
     type Item = KVBytes;
 
@@ -357,23 +316,21 @@ impl DB {
     ///
     /// # Panics
     ///
-    /// * Panics if the column family doesn't exist
+    /// * Panics if the column family doesn't exist.
     pub fn open_cf<P: AsRef<Path>>(opts: &Options, path: P, cfs: &[&str]) -> Result<DB, Error> {
         let path = path.as_ref();
-
         let cpath = match CString::new(path.to_string_lossy().as_bytes()) {
             Ok(c) => c,
             Err(_) => {
                 return Err(Error::new("Failed to convert path to CString \
-                                       when opening rocksdb"
+                                       when opening DB."
                     .to_owned()))
             }
         };
-        let cpath_ptr = cpath.as_ptr();
 
         if let Err(e) = fs::create_dir_all(&path) {
-            return Err(Error::new(format!("Failed to create rocksdb \
-                                           directory: {:?}",
+            return Err(Error::new(format!("Failed to create RocksDB\
+                                           directory: `{:?}`.",
                                           e)));
         }
 
@@ -382,7 +339,7 @@ impl DB {
 
         if cfs.len() == 0 {
             unsafe {
-                db = ffi_try!(ffi::rocksdb_open(opts.inner, cpath_ptr as *const _));
+                db = ffi_try!(ffi::rocksdb_open(opts.inner, cpath.as_ptr() as *const _));
             }
         } else {
             let mut cfs_v = cfs.to_vec();
@@ -409,7 +366,7 @@ impl DB {
 
             unsafe {
                 db = ffi_try!(ffi::rocksdb_open_column_families(opts.inner,
-                                                                cpath_ptr as *const _,
+                                                                cpath.as_ptr() as *const _,
                                                                 cfs_v.len() as c_int,
                                                                 cfnames.as_ptr() as *const _,
                                                                 cfopts.as_ptr(),
@@ -479,10 +436,10 @@ impl DB {
 
     pub fn get_opt(&self, key: &[u8], readopts: &ReadOptions) -> Result<Option<DBVector>, Error> {
         if readopts.inner.is_null() {
-            return Err(Error::new("Unable to create rocksdb read options. \
+            return Err(Error::new("Unable to create RocksDB read options. \
                                    This is a fairly trivial call, and its \
                                    failure may be indicative of a \
-                                   mis-compiled or mis-loaded rocksdb \
+                                   mis-compiled or mis-loaded RocksDB \
                                    library."
                 .to_owned()));
         }
@@ -513,10 +470,10 @@ impl DB {
                       readopts: &ReadOptions)
                       -> Result<Option<DBVector>, Error> {
         if readopts.inner.is_null() {
-            return Err(Error::new("Unable to create rocksdb read options. \
+            return Err(Error::new("Unable to create RocksDB read options. \
                                    This is a fairly trivial call, and its \
                                    failure may be indicative of a \
-                                   mis-compiled or mis-loaded rocksdb \
+                                   mis-compiled or mis-loaded RocksDB \
                                    library."
                 .to_owned()));
         }

src/rocksdb_options.rs

@@ -88,7 +88,7 @@ impl Default for BlockBasedOptions {
     fn default() -> BlockBasedOptions {
         let block_opts = unsafe { ffi::rocksdb_block_based_options_create() };
         if block_opts.is_null() {
-            panic!("Could not create rocksdb block based options".to_owned());
+            panic!("Could not create RocksDB block based options");
         }
         BlockBasedOptions { inner: block_opts }
     }
@@ -828,14 +828,13 @@ impl Default for Options {
         unsafe {
             let opts = ffi::rocksdb_options_create();
             if opts.is_null() {
-                panic!("Could not create rocksdb options".to_owned());
+                panic!("Could not create RocksDB options");
             }
             Options { inner: opts }
         }
     }
 }
 
-
 impl WriteOptions {
     pub fn new() -> WriteOptions {
         WriteOptions::default()
@@ -858,7 +857,7 @@ impl Default for WriteOptions {
     fn default() -> WriteOptions {
         let write_opts = unsafe { ffi::rocksdb_writeoptions_create() };
         if write_opts.is_null() {
-            panic!("Could not create rocksdb write options".to_owned());
+            panic!("Could not create RocksDB write options");
         }
         WriteOptions { inner: write_opts }
     }