Struct FuseWriter 

pub struct FuseWriter { /* private fields */ }

Builds a .fsdb file.

An object is stored once; any number of keys may point at it. That is the whole point of the format — a million keys sharing one payload cost one copy on disk.

Example

use fusedb::FuseWriter;
use std::collections::BTreeMap;

let mut w = FuseWriter::new();

let mut google = BTreeMap::new();
google.insert("company", "Google");

// one object, three keys
let oid = w.add_object(&google)?;
w.add_key("google.com", oid)?;
w.add_key("8.8.8.8", oid)?;
w.add_key("8.8.4.4", oid)?;

w.build("db.fsdb")?;

Deduplication

add_object always appends a new object, exactly like the Python FuseWriter. Use add_object_deduped when you want identical payloads collapsed into a single stored object.

Implementations

impl FuseWriter

pub fn new() -> Self

Create a new, empty writer.

pub fn add_object_raw(&mut self, raw: impl AsRef<[u8]>) -> usize

Store pre-encoded bytes as a new object. Returns its object ID.

The bytes are written to disk verbatim. If you want the file to be readable by the Python package, they must be MessagePack — which is what add_object produces for you.

pub fn add_object_raw_deduped(&mut self, raw: impl AsRef<[u8]>) -> usize

Store pre-encoded bytes, reusing an existing object when the payload is byte-identical to one already added through this method.

pub fn add_key( &mut self, key: impl AsRef<[u8]>, obj_id: usize, ) -> FuseResult<()>

Map key to an existing object ID.

Keys are arbitrary byte strings — UTF-8 text, binary, packed IPs. Adding the same key twice overwrites the earlier mapping.

Errors

FuseError::InvalidArg if obj_id was never returned by an add_object* call, or if key is longer than MAX_KEY_LEN bytes.

pub fn add_raw( &mut self, key: impl AsRef<[u8]>, raw: impl AsRef<[u8]>, ) -> FuseResult<usize>

Store raw bytes and point key at them, in one call.

pub fn add_object<T: Serialize + ?Sized>( &mut self, value: &T, ) -> FuseResult<usize>

Serialise value to MessagePack and store it as a new object.

The encoding matches Python’s msgpack.packb(value, use_bin_type=True), so anything written here decodes in the Python package unchanged.

pub fn add_object_deduped<T: Serialize + ?Sized>( &mut self, value: &T, ) -> FuseResult<usize>

Like add_object, but collapses values that encode to identical bytes into a single stored object.

pub fn add<T: Serialize + ?Sized>( &mut self, key: impl AsRef<[u8]>, value: &T, ) -> FuseResult<usize>

Convenience: add_object + add_key.

pub fn build(&self, path: impl AsRef<Path>) -> FuseResult<BuildReport>

Write the .fsdb file atomically: tmp → fsync → rename.

Readers holding the previous file open keep seeing consistent data through their existing mmap.

pub fn num_objects(&self) -> usize

Objects staged so far.

pub fn num_keys(&self) -> usize

Keys staged so far.

pub fn is_empty(&self) -> bool

Is the writer empty?

Trait Implementations

impl Debug for FuseWriter

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for FuseWriter

fn default() -> Self

Returns the “default value” for a type.