embedded_sdmmc/

lib.rs

//! # embedded-sdmmc
//!
//! > An SD/MMC Library written in Embedded Rust
//!
//! This crate is intended to allow you to read/write files on a FAT formatted
//! SD card on your Rust Embedded device, as easily as using the `SdFat` Arduino
//! library. It is written in pure-Rust, is `#![no_std]` and does not use
//! `alloc` or `collections` to keep the memory footprint low. In the first
//! instance it is designed for readability and simplicity over performance.
//!
//! ## Using the crate
//!
//! You will need something that implements the `BlockDevice` trait, which can
//! read and write the 512-byte blocks (or sectors) from your card. If you were
//! to implement this over USB Mass Storage, there's no reason this crate
//! couldn't work with a USB Thumb Drive, but we only supply a `BlockDevice`
//! suitable for reading SD and SDHC cards over SPI.
//!
//! ```rust
//! use embedded_sdmmc::{Error, Mode, SdCard, SdCardError, TimeSource, VolumeIdx, VolumeManager};
//!
//! fn example<S, D, T>(spi: S, delay: D, ts: T) -> Result<(), Error<SdCardError>>
//! where
//!     S: embedded_hal::spi::SpiDevice,
//!     D: embedded_hal::delay::DelayNs,
//!     T: TimeSource,
//! {
//!     let sdcard = SdCard::new(spi, delay);
//!     println!("Card size is {} bytes", sdcard.num_bytes()?);
//!     let mut volume_mgr = VolumeManager::new(sdcard, ts);
//!     let mut volume0 = volume_mgr.open_volume(VolumeIdx(0))?;
//!     println!("Volume 0: {:?}", volume0);
//!     let mut root_dir = volume0.open_root_dir()?;
//!     let mut my_file = root_dir.open_file_in_dir("MY_FILE.TXT", Mode::ReadOnly)?;
//!     while !my_file.is_eof() {
//!         let mut buffer = [0u8; 32];
//!         let num_read = my_file.read(&mut buffer)?;
//!         for b in &buffer[0..num_read] {
//!             print!("{}", *b as char);
//!         }
//!     }
//!     Ok(())
//! }
//! ```
//!
//! ## Features
//!
//! * `log`: Enabled by default. Generates log messages using the `log` crate.
//! * `defmt-log`: By turning off the default features and enabling the
//! `defmt-log` feature you can configure this crate to log messages over defmt
//! instead.
//!
//! You cannot enable both the `log` feature and the `defmt-log` feature.

#![cfg_attr(not(test), no_std)]
#![deny(missing_docs)]

// ****************************************************************************
//
// Imports
//
// ****************************************************************************

#[cfg(test)]
#[macro_use]
extern crate hex_literal;

#[macro_use]
mod structure;

pub mod blockdevice;
pub mod fat;
pub mod filesystem;
pub mod sdcard;

use filesystem::SearchId;

#[doc(inline)]
pub use crate::blockdevice::{Block, BlockCount, BlockDevice, BlockIdx};

#[doc(inline)]
pub use crate::fat::FatVolume;

#[doc(inline)]
pub use crate::filesystem::{
    Attributes, ClusterId, DirEntry, Directory, File, FilenameError, Mode, RawDirectory, RawFile,
    ShortFileName, TimeSource, Timestamp, MAX_FILE_SIZE,
};

use filesystem::DirectoryInfo;

#[doc(inline)]
pub use crate::sdcard::Error as SdCardError;

#[doc(inline)]
pub use crate::sdcard::SdCard;

mod volume_mgr;
#[doc(inline)]
pub use volume_mgr::VolumeManager;

#[cfg(all(feature = "defmt-log", feature = "log"))]
compile_error!("Cannot enable both log and defmt-log");

#[cfg(feature = "log")]
use log::{debug, trace, warn};

#[cfg(feature = "defmt-log")]
use defmt::{debug, trace, warn};

#[cfg(all(not(feature = "defmt-log"), not(feature = "log")))]
#[macro_export]
/// Like log::debug! but does nothing at all
macro_rules! debug {
    ($($arg:tt)+) => {};
}

#[cfg(all(not(feature = "defmt-log"), not(feature = "log")))]
#[macro_export]
/// Like log::trace! but does nothing at all
macro_rules! trace {
    ($($arg:tt)+) => {};
}

#[cfg(all(not(feature = "defmt-log"), not(feature = "log")))]
#[macro_export]
/// Like log::warn! but does nothing at all
macro_rules! warn {
    ($($arg:tt)+) => {};
}

// ****************************************************************************
//
// Public Types
//
// ****************************************************************************

/// All the ways the functions in this crate can fail.
#[cfg_attr(feature = "defmt-log", derive(defmt::Format))]
#[derive(Debug, Clone)]
pub enum Error<E>
where
    E: core::fmt::Debug,
{
    /// The underlying block device threw an error.
    DeviceError(E),
    /// The filesystem is badly formatted (or this code is buggy).
    FormatError(&'static str),
    /// The given `VolumeIdx` was bad,
    NoSuchVolume,
    /// The given filename was bad
    FilenameError(FilenameError),
    /// Out of memory opening volumes
    TooManyOpenVolumes,
    /// Out of memory opening directories
    TooManyOpenDirs,
    /// Out of memory opening files
    TooManyOpenFiles,
    /// Bad handle given
    BadHandle,
    /// That file or directory doesn't exist
    NotFound,
    /// You can't open a file twice or delete an open file
    FileAlreadyOpen,
    /// You can't open a directory twice
    DirAlreadyOpen,
    /// You can't open a directory as a file
    OpenedDirAsFile,
    /// You can't open a file as a directory
    OpenedFileAsDir,
    /// You can't delete a directory as a file
    DeleteDirAsFile,
    /// You can't close a volume with open files or directories
    VolumeStillInUse,
    /// You can't open a volume twice
    VolumeAlreadyOpen,
    /// We can't do that yet
    Unsupported,
    /// Tried to read beyond end of file
    EndOfFile,
    /// Found a bad cluster
    BadCluster,
    /// Error while converting types
    ConversionError,
    /// The device does not have enough space for the operation
    NotEnoughSpace,
    /// Cluster was not properly allocated by the library
    AllocationError,
    /// Jumped to free space during FAT traversing
    UnterminatedFatChain,
    /// Tried to open Read-Only file with write mode
    ReadOnly,
    /// Tried to create an existing file
    FileAlreadyExists,
    /// Bad block size - only 512 byte blocks supported
    BadBlockSize(u16),
    /// Bad offset given when seeking
    InvalidOffset,
    /// Disk is full
    DiskFull,
    /// A directory with that name already exists
    DirAlreadyExists,
}

impl<E> From<E> for Error<E>
where
    E: core::fmt::Debug,
{
    fn from(value: E) -> Error<E> {
        Error::DeviceError(value)
    }
}

/// A partition with a filesystem within it.
#[cfg_attr(feature = "defmt-log", derive(defmt::Format))]
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub struct RawVolume(SearchId);

impl RawVolume {
    /// Convert a raw volume into a droppable [`Volume`]
    pub fn to_volume<
        D,
        T,
        const MAX_DIRS: usize,
        const MAX_FILES: usize,
        const MAX_VOLUMES: usize,
    >(
        self,
        volume_mgr: &mut VolumeManager<D, T, MAX_DIRS, MAX_FILES, MAX_VOLUMES>,
    ) -> Volume<D, T, MAX_DIRS, MAX_FILES, MAX_VOLUMES>
    where
        D: crate::BlockDevice,
        T: crate::TimeSource,
    {
        Volume::new(self, volume_mgr)
    }
}

/// An open volume on disk, which closes on drop.
///
/// In contrast to a `RawVolume`, a `Volume` holds a mutable reference to its
/// parent `VolumeManager`, which restricts which operations you can perform.
///
/// If you drop a value of this type, it closes the volume automatically, but
/// any error that may occur will be ignored. To handle potential errors, use
/// the [`Volume::close`] method.
pub struct Volume<'a, D, T, const MAX_DIRS: usize, const MAX_FILES: usize, const MAX_VOLUMES: usize>
where
    D: crate::BlockDevice,
    T: crate::TimeSource,
{
    raw_volume: RawVolume,
    volume_mgr: &'a mut VolumeManager<D, T, MAX_DIRS, MAX_FILES, MAX_VOLUMES>,
}

impl<'a, D, T, const MAX_DIRS: usize, const MAX_FILES: usize, const MAX_VOLUMES: usize>
    Volume<'a, D, T, MAX_DIRS, MAX_FILES, MAX_VOLUMES>
where
    D: crate::BlockDevice,
    T: crate::TimeSource,
{
    /// Create a new `Volume` from a `RawVolume`
    pub fn new(
        raw_volume: RawVolume,
        volume_mgr: &'a mut VolumeManager<D, T, MAX_DIRS, MAX_FILES, MAX_VOLUMES>,
    ) -> Volume<'a, D, T, MAX_DIRS, MAX_FILES, MAX_VOLUMES> {
        Volume {
            raw_volume,
            volume_mgr,
        }
    }

    /// Open the volume's root directory.
    ///
    /// You can then read the directory entries with `iterate_dir`, or you can
    /// use `open_file_in_dir`.
    pub fn open_root_dir(
        &mut self,
    ) -> Result<crate::Directory<D, T, MAX_DIRS, MAX_FILES, MAX_VOLUMES>, Error<D::Error>> {
        let d = self.volume_mgr.open_root_dir(self.raw_volume)?;
        Ok(d.to_directory(self.volume_mgr))
    }

    /// Convert back to a raw volume
    pub fn to_raw_volume(self) -> RawVolume {
        let v = self.raw_volume;
        core::mem::forget(self);
        v
    }

    /// Consume the `Volume` handle and close it. The behavior of this is similar
    /// to using [`core::mem::drop`] or letting the `Volume` go out of scope,
    /// except this lets the user handle any errors that may occur in the process,
    /// whereas when using drop, any errors will be discarded silently.
    pub fn close(self) -> Result<(), Error<D::Error>> {
        let result = self.volume_mgr.close_volume(self.raw_volume);
        core::mem::forget(self);
        result
    }
}

impl<'a, D, T, const MAX_DIRS: usize, const MAX_FILES: usize, const MAX_VOLUMES: usize> Drop
    for Volume<'a, D, T, MAX_DIRS, MAX_FILES, MAX_VOLUMES>
where
    D: crate::BlockDevice,
    T: crate::TimeSource,
{
    fn drop(&mut self) {
        _ = self.volume_mgr.close_volume(self.raw_volume)
    }
}

impl<'a, D, T, const MAX_DIRS: usize, const MAX_FILES: usize, const MAX_VOLUMES: usize>
    core::fmt::Debug for Volume<'a, D, T, MAX_DIRS, MAX_FILES, MAX_VOLUMES>
where
    D: crate::BlockDevice,
    T: crate::TimeSource,
{
    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
        write!(f, "Volume({})", self.raw_volume.0 .0)
    }
}

#[cfg(feature = "defmt-log")]
impl<'a, D, T, const MAX_DIRS: usize, const MAX_FILES: usize, const MAX_VOLUMES: usize>
    defmt::Format for Volume<'a, D, T, MAX_DIRS, MAX_FILES, MAX_VOLUMES>
where
    D: crate::BlockDevice,
    T: crate::TimeSource,
{
    fn format(&self, fmt: defmt::Formatter) {
        defmt::write!(fmt, "Volume({})", self.raw_volume.0 .0)
    }
}

/// Internal information about a Volume
#[cfg_attr(feature = "defmt-log", derive(defmt::Format))]
#[derive(Debug, PartialEq, Eq)]
pub(crate) struct VolumeInfo {
    /// Search ID for this volume.
    volume_id: RawVolume,
    /// TODO: some kind of index
    idx: VolumeIdx,
    /// What kind of volume this is
    volume_type: VolumeType,
}

/// This enum holds the data for the various different types of filesystems we
/// support.
#[cfg_attr(feature = "defmt-log", derive(defmt::Format))]
#[derive(Debug, PartialEq, Eq)]
pub enum VolumeType {
    /// FAT16/FAT32 formatted volumes.
    Fat(FatVolume),
}

/// A number which identifies a volume (or partition) on a disk.
///
/// `VolumeIdx(0)` is the first primary partition on an MBR partitioned disk.
#[cfg_attr(feature = "defmt-log", derive(defmt::Format))]
#[derive(Debug, PartialEq, Eq, Copy, Clone)]
pub struct VolumeIdx(pub usize);

/// Marker for a FAT32 partition. Sometimes also use for FAT16 formatted
/// partitions.
const PARTITION_ID_FAT32_LBA: u8 = 0x0C;
/// Marker for a FAT16 partition with LBA. Seen on a Raspberry Pi SD card.
const PARTITION_ID_FAT16_LBA: u8 = 0x0E;
/// Marker for a FAT16 partition. Seen on a card formatted with the official
/// SD-Card formatter.
const PARTITION_ID_FAT16: u8 = 0x06;
/// Marker for a FAT32 partition. What Macosx disk utility (and also SD-Card formatter?)
/// use.
const PARTITION_ID_FAT32_CHS_LBA: u8 = 0x0B;

// ****************************************************************************
//
// Unit Tests
//
// ****************************************************************************

// None

// ****************************************************************************
//
// End Of File
//
// ****************************************************************************