Crate freqfs 

freqfs is an in-memory cache layer over tokio::fs with least-frequently-used eviction.

freqfs automatically caches the most frequently-used files and backs up the others to disk. This allows the developer to create and update large collections of data purely in-memory without explicitly sync’ing to disk, while still retaining the flexibility to run on a host with extremely limited memory. This is especially useful for web serving, database, and data science applications.

See the examples directory for detailed usage examples.

This crate assumes that file paths are valid Unicode and may panic if it encounters a file path which is not valid Unicode.

It also assumes that all file I/O under the cache root directory (the one whose path is passed to load) is routed through the cache (not e.g. via tokio::fs or std::fs elsewhere). It may raise an std::io::Error or panic if this assumption is not valid.

In the case that your program may not have permission to write to a filesystem entry, be sure to check the permissions before modifying it. The background cleanup thread will panic if it attempts an impermissible write operation.

Macros

name_from_str

Implement Name for a type which implements std::str::FromStr, to compare with a key type which dereferences to a str.

Structs

Cache

An in-memory cache layer over tokio::fs with least-frequently-used (LFU) eviction.

Dir

A filesystem directory

DirLock

A clone-able wrapper type over a RwLock on a directory.

FileLock

A futures-aware read-write lock on a file

Enums

DirEntry

A directory entry, either a FileLock or a sub-DirLock.

Traits

DirDeref

A helper trait to coerce container types like Arc into a borrowed Dir.

FileDeref

A helper trait to coerce container types like Arc into a borrowed file.

FileLoad

Load a file-backed data structure.

FileSave

Write a file-backed data structure to the filesystem.

Name

A type that can be used to look up a directory entry without calling to_string(), to avoid unnecessary heap allocations.

Type Aliases

DirReadGuard

A read lock on a directory.

DirReadGuardOwned

An owned read lock on a directory.

DirWriteGuard

A write lock on a directory.

DirWriteGuardOwned

An owned write lock on a directory.

FileReadGuard

A read guard on a file

FileReadGuardOwned

An owned read guard on a file

FileWriteGuard

A write guard on a file

FileWriteGuardOwned

An owned write guard on a file