harmos-storage 0.1.2

/* ***
 *
 * Harmos
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * ***
 */

/* === Modules === */

pub(super) mod checkpoint;
mod creation;
mod mutations;
mod perform;
mod producer;
mod session;
mod state;

/* === Re-Exports === */

pub(crate) use perform::perform;

/* === Imports === */

// Standard Library Imports
use std::sync::atomic::{AtomicU64, Ordering};
use std::sync::{Arc, Mutex};
use std::time::Duration;

// Third Party Imports
use sha2::{Digest, Sha256};

// Local Imports
use super::manager::{ENTRY_OVERHEAD, Operation, Pending, State, Target, encoded_size};
use super::*;
use crate::{Error, Result};
use session::Session;

/* === Constants === */

static NEXT_FILE: AtomicU64 = AtomicU64::new(1);

/* === Macros === */

/* === Type Aliases === */

/* === Structs === */

pub struct StorageFile {
    manager: StorageManager<super::manager::ErasedCatalog>,
    id: u64,
    progress: Arc<Mutex<Progress>>,
    session: Option<FileSession>,
}

struct CancelProduction {
    manager: StorageManager<super::manager::ErasedCatalog>,
    id: u64,
    armed: bool,
    generation: Option<u64>,
}

#[derive(Default)]
struct Progress {
    generation: u64,
    ready: bool,
    closed: bool,
    completed: u64,
    length: u64,
    reference: Option<FileReference>,
    failure: Option<Arc<Error>>,
}

pub(super) struct FileState {
    metadata: Arc<FileMetadata>,
    staging: StagedFile,
    session: Option<Session>,
    mutation: Option<mutations::Mutation>,
    extra: Option<StagedFile>,
    progress: Arc<Mutex<Progress>>,
    hash: Sha256,
    length: u64,
    ticket: u64,
    command: Option<Command>,
    abandoned: bool,
    in_flight: bool,
    retrying: bool,
    base_bytes: usize,
    reference_bytes: usize,
}

/* === Enums === */

enum Command {
    Create,
    Resume { expected: u64, next: u64 },
    Write(Arc<[u8]>),
    Finish { target: Option<Target>, sha256: [u8; 32] },
    Abort,
}

enum Await {
    Ready,
    Written(u64),
    Finished,
    Aborted,
}

pub(super) enum FileAction {
    Create { id: u64, metadata: Arc<FileMetadata>, staging: StagedFile, resumable: bool },
    Resume { id: u64, staging: StagedFile, expected: u64, next: u64 },
    Write { id: u64, staging: StagedFile, offset: u64, bytes: Arc<[u8]> },
    Finish { id: u64, staging: StagedFile, metadata: Arc<FileMetadata>, target: Target, length: u64, sha256: [u8; 32] },
    Abandon { id: u64, staging: StagedFile, extra: Option<StagedFile> },
    Abort { id: u64, staging: StagedFile, extra: Option<StagedFile> },
    Refuse { id: u64 },
}

pub(super) enum FileCompleted {
    Created,
    Resumed(u64),
    Written,
    Finished(Box<FileReference>),
    Aborted,
}

/* === Traits === */

/* === Implementations === */

/* === Public Functions === */

/* === Private Functions === */

fn file_bytes(metadata: &FileMetadata, history: &StoreHistory) -> Result<(usize, usize)> {
    let reference = encoded_size(metadata)?
        .checked_add(encoded_size(history)?)
        .and_then(|size| size.checked_add(ENTRY_OVERHEAD))
        .ok_or_else(size_error)?;
    let base = reference.checked_mul(8).ok_or_else(size_error)?;
    Ok((reference, base))
}

fn closed() -> Error {
    Error::Closing { domain: "storage file" }
}

fn size_error() -> Error {
    Error::InvalidInput { field: "file admission", reason: "size or position overflow" }
}

fn admission(state: &State) -> Result<()> {
    if state.status.closing {
        return Err(closed());
    }
    if !state.ready || !state.status.running {
        return Err(Error::NotReady { domain: "storage" });
    }
    if let Some(source) = &state.status.failure {
        return Err(Error::Persistence { source: source.clone() });
    }
    Ok(())
}

/* === Tests === */