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use std::ffi::OsStr;
use std::os::unix::ffi::OsStrExt;
use libc::{c_int, ENOENT, ENOSPC};
use crate::disk::block::{DirectoryBlock, DirectoryEntry};
use crate::disk::inode::{Inode};
use crate::AyaFS;
impl AyaFS {
pub(crate) fn remove_direntry(
&mut self,
parent_inode: &mut Inode,
entry_index: u32
) -> Result<(), c_int> {
let block_index_within_inode = (entry_index / 15) as usize;
let entry_index_within_block = (entry_index % 15) as usize;
match self.access_block_mut::<DirectoryBlock>(parent_inode, block_index_within_inode) {
Some(directory_block) => {
if directory_block.block.query(entry_index_within_block) {
directory_block.block.deallocate(entry_index_within_block);
directory_block.block.entries[entry_index_within_block] = DirectoryEntry::default();
Ok(())
} else {
Err(ENOENT)
}
}
None => Err(ENOENT),
}
}
pub(crate) fn add_direntry(
&mut self,
parent_inode: &mut Inode,
child_inode_index: u32,
child_inode_name: &OsStr,
child_inode: &Inode,
) -> Result<u32, c_int> {
// 找到第一个有空闲 DirEntry 的块, 从中分配一个 entry
let mut block_index_within_inode: usize = 0;
loop {
// 所有已经分配的块都用完, 需要额外分配一个块了
if block_index_within_inode as u32 == parent_inode.n_blocks {
if self.allocate_block_for(parent_inode).is_none() {
return Err(ENOSPC);
}
}
// 寻找当前块里有没有空闲空间
if let Some(directory_block) = self.access_block_mut::<DirectoryBlock>(parent_inode, block_index_within_inode) {
if let Some(entry_index_within_block) = directory_block.block.allocate() {
// 如果有空闲空间, 可以分配一个块
let name_len = child_inode_name.len() as u8;
let file_type = child_inode.mode.into();
let mut name = [0u8; 256];
name.copy_from_slice(child_inode_name.as_bytes());
let dir_entry = DirectoryEntry {
inode: child_inode_index,
record_len: 264,
name_len,
file_type,
name,
};
directory_block.block.entries[entry_index_within_block] = dir_entry;
let entry_index = block_index_within_inode * 15 + entry_index_within_block;
return Ok(entry_index as u32);
}
}
block_index_within_inode += 1;
};
}
pub(crate) fn get_direntry(
&mut self,
parent_inode: &Inode,
entry_index: u32
) -> Option<DirectoryEntry> {
let block_index_within_inode = (entry_index / 15) as usize;
let entry_index_within_block = (entry_index % 15) as usize;
self.access_block::<DirectoryBlock>(parent_inode, block_index_within_inode)
.and_then(|directory_block| {
if directory_block.block.query(entry_index_within_block) {
Some(directory_block.block.entries[entry_index_within_block].clone())
} else {
None
}
})
}
// TODO 实现一个带 cache 的版本
pub fn lookup_name(&mut self, parent_inode: &Inode, name: &OsStr) -> Result<(u32, u32, Inode), c_int> {
let mut entry_index = 0;
while entry_index < parent_inode.size {
if let Some(entry) = self.get_direntry(parent_inode, entry_index) {
if entry.name() == name {
let inode = self.get_inode(entry.inode as usize).unwrap().clone();
return Ok((entry.inode, entry_index, inode))
}
}
entry_index += 1;
}
Err(ENOENT)
}
}
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