Mercurial > lbo > hg > leveldb-rs
view src/types.rs @ 144:a60c595dcb4e
Make publishing leveldb impossible (set publish = false)
author | Lewin Bormann <lbo@spheniscida.de> |
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date | Tue, 03 Jan 2017 19:41:19 +0100 |
parents | 06c8d65b6367 |
children | 4a41aab21046 |
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//! A collection of fundamental and/or simple types used by other modules use std::error::Error; use std::fmt::{self, Display, Formatter}; use std::io; use std::result; #[derive(Debug, PartialOrd, PartialEq)] pub enum ValueType { TypeDeletion = 0, TypeValue = 1, } /// Represents a sequence number of a single entry. pub type SequenceNumber = u64; pub const MAX_SEQUENCE_NUMBER: SequenceNumber = (1 << 56) - 1; #[derive(Clone, Debug)] #[allow(dead_code)] pub enum Status { OK, NotFound(String), Corruption(String), NotSupported(String), InvalidArgument(String), PermissionDenied(String), IOError(String), Unknown(String), } impl Display for Status { fn fmt(&self, fmt: &mut Formatter) -> result::Result<(), fmt::Error> { fmt.write_str(self.description()) } } impl Error for Status { fn description(&self) -> &str { match *self { Status::OK => "ok", Status::NotFound(ref s) => s, Status::Corruption(ref s) => s, Status::NotSupported(ref s) => s, Status::InvalidArgument(ref s) => s, Status::PermissionDenied(ref s) => s, Status::IOError(ref s) => s, Status::Unknown(ref s) => s, } } } /// LevelDB's result type pub type Result<T> = result::Result<T, Status>; pub fn from_io_result<T>(e: io::Result<T>) -> Result<T> { match e { Ok(r) => result::Result::Ok(r), Err(e) => { let err = e.description().to_string(); let r = match e.kind() { io::ErrorKind::NotFound => Err(Status::NotFound(err)), io::ErrorKind::InvalidData => Err(Status::Corruption(err)), io::ErrorKind::InvalidInput => Err(Status::InvalidArgument(err)), io::ErrorKind::PermissionDenied => Err(Status::PermissionDenied(err)), _ => Err(Status::IOError(err)), }; r } } } /// Denotes a key range pub struct Range<'a> { pub start: &'a [u8], pub limit: &'a [u8], } /// An extension of the standard `Iterator` trait that supports some methods necessary for LevelDB. /// This works because the iterators used are stateful and keep the last returned element. /// /// Note: Implementing types are expected to hold `!valid()` before the first call to `next()`. pub trait LdbIterator: Iterator { // We're emulating LevelDB's Slice type here using actual slices with the lifetime of the // iterator. The lifetime of the iterator is usually the one of the backing storage (Block, // MemTable, SkipMap...) // type Item = (&'a [u8], &'a [u8]); /// Seek the iterator to `key` or the next bigger key. If the seek is invalid (past last /// element), the iterator is reset() and not valid. /// After a seek to an existing key, current() returns that entry. fn seek(&mut self, key: &[u8]); /// Resets the iterator to be `!valid()` again (before first element) fn reset(&mut self); /// Returns true if `current()` would return a valid item. fn valid(&self) -> bool; /// Return the current item (i.e. the item most recently returned by next()) fn current(&self) -> Option<Self::Item>; /// Go to the previous item. This is inefficient for most iterators. fn prev(&mut self) -> Option<Self::Item>; fn seek_to_first(&mut self) { self.reset(); self.next(); } } /// Describes a file on disk. #[derive(Clone, Debug, PartialEq)] pub struct FileMetaData { pub allowed_seeks: isize, pub num: u64, pub size: u64, // these are in InternalKey format: pub smallest: Vec<u8>, pub largest: Vec<u8>, }