Struct FrozenFile

Source

pub struct FrozenFile { /* private fields */ }

Expand description

Custom implementation of std::fs::File

§Example

use frozen_core::ffile::{FrozenFile, FFCfg};

let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("tmp_frozen_file");

let cfg = FFCfg {
    mid: 0x00,
    chunk_size: 0x10,
    path: path.to_path_buf(),
    initial_chunk_amount: 0x0A,
};

let file = FrozenFile::new(cfg.clone()).unwrap();
assert_eq!(file.length().unwrap(), 0x10 * 0x0A);

let mut data = vec![1u8; 0x10];
assert!(file.pwrite(data.as_mut_ptr(), 0).is_ok());
assert!(file.sync().is_ok());

let mut buf = vec![0u8; data.len()];
assert!(file.pread(buf.as_mut_ptr(), 0).is_ok());
assert_eq!(buf, data);

assert!(FrozenFile::new(cfg.clone()).is_err());

assert!(file.delete().is_ok());
assert!(!path.exists());

drop(file);
assert!(FrozenFile::new(cfg).is_ok());

Implementations§

Source §

impl FrozenFile

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pub fn cfg(&self) -> &FFCfg

Fetch config used for FrozenFile

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pub fn length(&self) -> FrozenRes<usize>

Read current length of FrozenFile

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pub fn fd(&self) -> i32

Get file descriptor for FrozenFile

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pub fn exists(&self) -> FrozenRes<bool>

Check if FrozenFile exists on the fs

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pub fn new(cfg: FFCfg) -> FrozenRes<Self>

Create a new or open an existing FrozenFile

§`FFCfg`

All configs for FrozenFile are stored in FFCfg

§Important

The cfg must not change any of its properties for the entire life of FrozenFile, one must use config stores like Rta to store config

§Multiple Instances

We acquire an exclusive lock for the entire file, this protects against operating with multiple simultenious instance of FrozenFile, when trying to call FrozenFile::new when already called, FFileErr::Lck error will be thrown

§Example

use frozen_core::ffile::{FrozenFile, FFCfg};

let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("tmp_frozen_file");

let cfg = FFCfg {
    mid: 0x00,
    chunk_size: 0x10,
    path: path.to_path_buf(),
    initial_chunk_amount: 0x0A,
};

let file = FrozenFile::new(cfg).unwrap();
assert_eq!(file.length().unwrap(), 0x10 * 0x0A);

Source

pub fn grow(&self, count: usize) -> FrozenRes<()>

Grow file size of FrozenFile by given count of chunks

§Example

use frozen_core::ffile::{FrozenFile, FFCfg};

let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("tmp_frozen_file");

let cfg = FFCfg {
    mid: 0x00,
    chunk_size: 0x10,
    path: path.to_path_buf(),
    initial_chunk_amount: 0x0A,
};

let file = FrozenFile::new(cfg).unwrap();
assert_eq!(file.length().unwrap(), 0x10 * 0x0A);

file.grow(0x20).unwrap();
assert_eq!(file.length().unwrap(), 0x10 * (0x0A + 0x20));

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pub fn sync(&self) -> FrozenRes<()>

Syncs in-mem data on the storage device

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pub fn sync_range(&self, index: usize, count: usize) -> FrozenRes<()>

Initiates writeback (best-effort) of dirty pages in the specified range

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pub fn delete(&self) -> FrozenRes<()>

Delete FrozenFile from fs

§Example

use frozen_core::ffile::{FrozenFile, FFCfg};

let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("tmp_frozen_file");

let cfg = FFCfg {
    mid: 0x00,
    chunk_size: 0x10,
    path: path.to_path_buf(),
    initial_chunk_amount: 0x0A,
};

let file = FrozenFile::new(cfg).unwrap();
assert!(file.exists().unwrap());

file.delete().unwrap();
assert!(!file.exists().unwrap());