Merge pull request #246 from nervosnetwork/pinnable-slice

Implement PinnableSlice based API
master
Oleksandr Anyshchenko 6 years ago committed by GitHub
commit 5023d717af
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GPG Key ID: 4AEE18F83AFDEB23
  1. 139
      src/db.rs
  2. 4
      src/lib.rs
  3. 26
      tests/test_pinnable_slice.rs

@ -938,6 +938,95 @@ impl DB {
self.get_cf_opt(cf, key.as_ref(), &ReadOptions::default())
}
/// Return the value associated with a key using RocksDB's PinnableSlice
/// so as to avoid unnecessary memory copy.
pub fn get_pinned_opt<K: AsRef<[u8]>>(
&self,
key: K,
readopts: &ReadOptions,
) -> Result<Option<DBPinnableSlice>, Error> {
if readopts.inner.is_null() {
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 \
library."
.to_owned(),
));
}
let key = key.as_ref();
unsafe {
let val = ffi_try!(ffi::rocksdb_get_pinned(
self.inner,
readopts.inner,
key.as_ptr() as *const c_char,
key.len() as size_t,
));
if val.is_null() {
Ok(None)
} else {
Ok(Some(DBPinnableSlice::from_c(val)))
}
}
}
/// Return the value associated with a key using RocksDB's PinnableSlice
/// so as to avoid unnecessary memory copy. Similar to get_pinned_opt but
/// leverages default options.
pub fn get_pinned<K: AsRef<[u8]>>(&self, key: K) -> Result<Option<DBPinnableSlice>, Error> {
self.get_pinned_opt(key, &ReadOptions::default())
}
/// Return the value associated with a key using RocksDB's PinnableSlice
/// so as to avoid unnecessary memory copy. Similar to get_pinned_opt but
/// allows specifying ColumnFamily
pub fn get_pinned_cf_opt<K: AsRef<[u8]>>(
&self,
cf: ColumnFamily,
key: K,
readopts: &ReadOptions,
) -> Result<Option<DBPinnableSlice>, Error> {
if readopts.inner.is_null() {
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 \
library."
.to_owned(),
));
}
let key = key.as_ref();
unsafe {
let val = ffi_try!(ffi::rocksdb_get_pinned_cf(
self.inner,
readopts.inner,
cf.inner,
key.as_ptr() as *const c_char,
key.len() as size_t,
));
if val.is_null() {
Ok(None)
} else {
Ok(Some(DBPinnableSlice::from_c(val)))
}
}
}
/// Return the value associated with a key using RocksDB's PinnableSlice
/// so as to avoid unnecessary memory copy. Similar to get_pinned_cf_opt but
/// leverages default options.
pub fn get_pinned_cf<K: AsRef<[u8]>>(
&self,
cf: ColumnFamily,
key: K,
) -> Result<Option<DBPinnableSlice>, Error> {
self.get_pinned_cf_opt(cf, key, &ReadOptions::default())
}
pub fn create_cf(&self, name: &str, opts: &Options) -> Result<ColumnFamily, Error> {
let cname = match CString::new(name.as_bytes()) {
Ok(c) => c,
@ -1597,6 +1686,56 @@ fn to_cpath<P: AsRef<Path>>(path: P) -> Result<CString, Error> {
}
}
/// Wrapper around RocksDB PinnableSlice struct.
///
/// With a pinnable slice, we can directly leverage in-memory data within
/// RocksDB toa void unnecessary memory copies. The struct here wraps the
/// returned raw pointer and ensures proper finalization work.
pub struct DBPinnableSlice<'a> {
ptr: *mut ffi::rocksdb_pinnableslice_t,
db: PhantomData<&'a DB>,
}
impl<'a> AsRef<[u8]> for DBPinnableSlice<'a> {
fn as_ref(&self) -> &[u8] {
// Implement this via Deref so as not to repeat ourselves
&*self
}
}
impl<'a> Deref for DBPinnableSlice<'a> {
type Target = [u8];
fn deref(&self) -> &[u8] {
unsafe {
let mut val_len: size_t = 0;
let val = ffi::rocksdb_pinnableslice_value(self.ptr, &mut val_len) as *mut u8;
slice::from_raw_parts(val, val_len)
}
}
}
impl<'a> Drop for DBPinnableSlice<'a> {
fn drop(&mut self) {
unsafe {
ffi::rocksdb_pinnableslice_destroy(self.ptr);
}
}
}
impl<'a> DBPinnableSlice<'a> {
/// Used to wrap a PinnableSlice from rocksdb to avoid unnecessary memcpy
///
/// # Unsafe
/// Requires that the pointer must be generated by rocksdb_get_pinned
pub unsafe fn from_c(ptr: *mut ffi::rocksdb_pinnableslice_t) -> DBPinnableSlice<'a> {
DBPinnableSlice {
ptr,
db: PhantomData,
}
}
}
#[test]
fn test_db_vector() {
use std::mem;

@ -71,8 +71,8 @@ mod slice_transform;
pub use compaction_filter::Decision as CompactionDecision;
pub use db::{
DBCompactionStyle, DBCompressionType, DBIterator, DBRawIterator, DBRecoveryMode, DBVector,
Direction, IteratorMode, ReadOptions, Snapshot, WriteBatch,
DBCompactionStyle, DBCompressionType, DBIterator, DBPinnableSlice, DBRawIterator,
DBRecoveryMode, DBVector, Direction, IteratorMode, ReadOptions, Snapshot, WriteBatch,
};
pub use slice_transform::SliceTransform;

@ -0,0 +1,26 @@
extern crate rocksdb;
mod util;
use rocksdb::{Options, DB};
use util::DBPath;
#[test]
fn test_pinnable_slice() {
let path = DBPath::new("_rust_rocksdb_pinnable_slice_test");
let mut opts = Options::default();
opts.create_if_missing(true);
let db = DB::open(&opts, &path).unwrap();
db.put(b"k1", b"value12345").unwrap();
let result = db.get_pinned(b"k1");
assert!(result.is_ok());
let value = result.unwrap();
assert!(value.is_some());
let pinnable_slice = value.unwrap();
assert_eq!(b"12345", &pinnable_slice[5..10]);
}
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