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use crate::layout::{FATDirEnt, FATShortDirEnt};
use crate::vfs::FileContent;
use crate::{CacheManager, Inode};
use alloc::string::{String, ToString};
use spin::MutexGuard;
pub enum DirIterMode {
LongIter,
ShortIter,
UsedIter,
Unused,
Enum,
Dirent,
}
#[allow(unused)]
impl DirIterMode {
pub fn is_long_iter(&self) -> bool {
matches!(self, Self::LongIter)
}
pub fn is_short_iter(&self) -> bool {
matches!(self, Self::ShortIter)
}
pub fn is_all_iter(&self) -> bool {
matches!(self, Self::UsedIter)
}
pub fn is_unused(&self) -> bool {
matches!(self, Self::Unused)
}
}
pub const FORWARD: bool = true;
pub const BACKWARD: bool = false;
const STEP_SIZE: u32 = core::mem::size_of::<FATDirEnt>() as u32;
pub struct DirIter<'a, T: CacheManager, F: CacheManager> {
pub lock: MutexGuard<'a, FileContent<T>>,
pub offset: Option<u32>,
pub mode: DirIterMode,
pub forward: bool,
pub inode: &'a Inode<T, F>,
}
impl<'a, T: CacheManager, F: CacheManager> DirIter<'a, T, F> {
#[allow(unused)]
#[inline(always)]
fn file_size(&self) -> u32 {
self.lock.size
}
#[allow(unused)]
#[inline(always)]
pub fn get_offset(&self) -> Option<u32> {
self.offset
}
#[allow(unused)]
#[inline(always)]
pub fn set_iter_offset(&mut self, offset: u32) {
if self.forward {
if offset == 0 {
self.offset = None;
} else {
self.offset = Some(offset - STEP_SIZE);
}
} else {
self.offset = Some(offset + STEP_SIZE);
}
}
pub fn current_clone(&mut self) -> Option<FATDirEnt> {
let mut dir_ent = FATDirEnt::empty();
if self.offset.is_some()
&& self.offset.unwrap() < self.file_size()
&& self.inode.read_at_block_cache(
&mut self.lock,
self.offset.unwrap() as usize,
dir_ent.as_bytes_mut(),
) != 0
{
Some(dir_ent)
} else {
None
}
}
#[allow(unused)]
#[inline(always)]
pub fn backward(mut self) -> Self {
self.forward = false;
self
}
#[allow(unused)]
#[inline(always)]
pub fn to_backward(&mut self) {
self.forward = false;
}
#[allow(unused)]
#[inline(always)]
pub fn forward(mut self) -> Self {
self.forward = true;
self
}
#[allow(unused)]
#[inline(always)]
pub fn toggle_direction(mut self) -> Self {
self.forward = !self.forward;
self
}
#[allow(unused)]
#[inline(always)]
pub fn short(mut self) -> Self {
self.mode = DirIterMode::ShortIter;
self
}
#[allow(unused)]
#[inline(always)]
pub fn long(mut self) -> Self {
self.mode = DirIterMode::LongIter;
self
}
#[allow(unused)]
#[inline(always)]
pub fn everything(mut self) -> Self {
self.mode = DirIterMode::Enum;
self
}
#[allow(unused)]
#[inline(always)]
pub fn all(mut self) -> Self {
self.mode = DirIterMode::UsedIter;
self
}
#[allow(unused)]
#[inline(always)]
pub fn unused(mut self) -> Self {
self.mode = DirIterMode::Unused;
self
}
pub fn write_to_current_ent(&mut self, ent: &FATDirEnt) {
if self.inode.write_at_block_cache(
&mut self.lock,
self.offset.unwrap() as usize,
ent.as_bytes(),
) != ent.as_bytes().len()
{
panic!("failed!");
}
}
pub fn step(&mut self) -> Option<FATDirEnt> {
let mut dir_ent: FATDirEnt = FATDirEnt::empty();
if self.forward {
let offset = self.offset.map(|offset| offset + STEP_SIZE).unwrap_or(0);
if offset >= self.file_size() {
return None;
}
self.inode
.read_at_block_cache(&mut self.lock, offset as usize, dir_ent.as_bytes_mut());
match self.mode {
DirIterMode::Enum | DirIterMode::Dirent => (),
_ => {
if dir_ent.last_and_unused() {
return None;
}
}
}
self.offset = Some(offset);
} else {
if self.offset.is_none() {
return None;
}
if self.offset.unwrap() == 0 {
self.offset = None;
return None;
}
self.offset = self.offset.map(|offset| offset - STEP_SIZE);
self.inode.read_at_block_cache(
&mut self.lock,
self.offset.unwrap() as usize,
dir_ent.as_bytes_mut(),
);
}
Some(dir_ent)
}
pub fn walk(self) -> DirWalker<'a, T, F> {
DirWalker { iter: self }
}
}
impl<T: CacheManager, F: CacheManager> Iterator for DirIter<'_, T, F> {
type Item = FATDirEnt;
fn next(&mut self) -> Option<Self::Item> {
while let Some(dir_ent) = self.step() {
fn check_dir_ent_legality(mode: &DirIterMode, dir_ent: &FATDirEnt) -> bool {
match mode {
DirIterMode::Unused => dir_ent.unused_not_last(),
DirIterMode::UsedIter => !dir_ent.unused(),
DirIterMode::LongIter => !dir_ent.unused() && dir_ent.is_long(),
DirIterMode::ShortIter => !dir_ent.unused() && dir_ent.is_short(),
DirIterMode::Enum => true,
DirIterMode::Dirent => !dir_ent.unused() || dir_ent.last_and_unused(),
}
}
if check_dir_ent_legality(&self.mode, &dir_ent) {
return Some(dir_ent);
}
}
None
}
}
pub struct DirWalker<'a, T: CacheManager, F: CacheManager> {
pub iter: DirIter<'a, T, F>,
}
impl<T: CacheManager, F: CacheManager> Iterator for DirWalker<'_, T, F> {
type Item = (String, FATShortDirEnt);
fn next(&mut self) -> Option<Self::Item> {
let mut name = String::new();
let mut should_be_ord = usize::MAX;
while let Some(dir_ent) = self.iter.next() {
if dir_ent.is_long() {
if dir_ent.is_last_long_dir_ent() {
name = dir_ent.get_name() + &name;
should_be_ord = dir_ent.ord() - 1;
} else if dir_ent.ord() == should_be_ord {
name = dir_ent.get_name() + &name;
should_be_ord -= 1;
} else {
unreachable!()
}
} else if dir_ent.is_short() {
if name.is_empty() {
name = dir_ent.get_name();
}
return Some((name, dir_ent.get_short_ent().unwrap().clone()));
}
}
None
}
}