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use std::ffi::OsStr;
use std::os::unix::ffi::OsStrExt;
use libc::{c_int, ENOENT, ENOSPC};
use crate::disk::block::{Block, DirectoryBlock, DirectoryEntry, DoubleIndirectBlock, IndirectBlock, TripleIndirectBlock};
use crate::disk::inode::{Inode, DIRECT_NUMBER};
use crate::{AyaFS, INODE_PER_BLOCK};
use crate::memory::cached_block::CachedBlock;
impl AyaFS {
pub(crate) fn access_block<T: Block>(&mut self, inode: &Inode, mut block_index_within_inode: usize) -> Option<&CachedBlock<T>> {
// direct block
if block_index_within_inode < DIRECT_NUMBER {
let block_index = inode.direct[block_index_within_inode] as usize;
return self.get_block::<T>(block_index);
} else {
block_index_within_inode -= DIRECT_NUMBER;
}
// indirect block
let indirect_number = INODE_PER_BLOCK;
if block_index_within_inode < indirect_number {
return if let Some(indirect_block) =
self.get_block::<IndirectBlock>(inode.single_indirect as usize)
{
let block_index = indirect_block.block.entries[block_index_within_inode] as usize;
self.get_block::<T>(block_index)
} else {
None
};
} else {
block_index_within_inode -= indirect_number;
}
// double indirect block
let double_indirect_number = INODE_PER_BLOCK * INODE_PER_BLOCK;
if block_index_within_inode < double_indirect_number {
if let Some(double_indirect_block) =
self.get_block::<DoubleIndirectBlock>(inode.double_indirect as usize)
{
// 取出 double indirect block
let indirect_block_index = double_indirect_block.block.indirect
[block_index_within_inode / INODE_PER_BLOCK]
as usize;
// 要找的 entry 在 double indirect block 中的第几个 indirect block
if let Some(indirect_block) = self.get_block::<IndirectBlock>(indirect_block_index)
{
let block_index = indirect_block.block.entries
[block_index_within_inode % INODE_PER_BLOCK]
as usize;
// 拿到 DirectoryBlock 的 index
return self.get_block::<T>(block_index);
}
}
return None;
} else {
block_index_within_inode -= double_indirect_number;
}
// triple indirect block
if let Some(triple_indirect_block) =
self.get_block::<TripleIndirectBlock>(inode.triple_indirect as usize)
{
// 取出 triple indirect block
let double_indirect_block_index = triple_indirect_block.block.double_indirect
[block_index_within_inode / (INODE_PER_BLOCK * INODE_PER_BLOCK)]
as usize;
// 要找的 entry 在 triple indirect block 中的第几个 double indirect block
if let Some(double_indirect_block) =
self.get_block::<DoubleIndirectBlock>(double_indirect_block_index)
{
// 取出 double indirect block
let indirect_block_index = double_indirect_block.block.indirect
[block_index_within_inode % (INODE_PER_BLOCK * INODE_PER_BLOCK)
/ INODE_PER_BLOCK] as usize;
// 要找的 entry 在 double indirect block 中的第几个 indirect block
if let Some(indirect_block) = self.get_block::<IndirectBlock>(indirect_block_index)
{
let block_index = indirect_block.block.entries
[block_index_within_inode % INODE_PER_BLOCK]
as usize;
// DirectoryBlock 的 index
return self.get_block::<T>(block_index);
}
}
}
None
}
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> {
let entry_index = parent_inode.size;
let block_index_within_inode = (entry_index / 15) as usize;
let entry_index_within_block = (entry_index % 15) as usize;
// TODO 如果 block 内 offset 是 0 （或者访问到 block_index_within_inode 无效?）则为 Inode 分配新的 block
// TODO 把新的 entry 写到对应位置
Err(ENOSPC)
}
pub(crate) fn get_direntry(
&mut self,
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>(inode, block_index_within_inode)
.map(|directory_block| {
directory_block.block.entries[entry_index_within_block].clone()
})
}
// pub(crate) fn get_direntry(
// &mut self,
// inode: &Inode,
// entry_index: u32,
// ) -> Option<DirectoryEntry> {
// // 每个 DirectoryBlock 里有 15 个 entry, 先确定 block 再确定 offset
// let mut block_index_within_inode = (entry_index / 15) as usize;
// let entry_index_within_block = (entry_index % 15) as usize;
//
// // direct block
// if block_index_within_inode < DIRECT_NUMBER {
// let block_index = inode.direct[block_index_within_inode] as usize;
// return self
// .get_block::<DirectoryBlock>(block_index)
// .map(|inode_block| inode_block.block.entries[entry_index_within_block].clone());
// } else {
// block_index_within_inode -= DIRECT_NUMBER;
// }
//
// // indirect block
// let indirect_number = INODE_PER_BLOCK;
// if block_index_within_inode < indirect_number {
// return if let Some(indirect_block) =
// self.get_block::<IndirectBlock>(inode.single_indirect as usize)
// {
// let block_index = indirect_block.block.entries[block_index_within_inode] as usize;
// self.get_block::<DirectoryBlock>(block_index)
// .map(|inode_block| inode_block.block.entries[entry_index_within_block].clone())
// } else {
// None
// };
// } else {
// block_index_within_inode -= indirect_number;
// }
//
// // double indirect block
// let double_indirect_number = INODE_PER_BLOCK * INODE_PER_BLOCK;
// if block_index_within_inode < double_indirect_number {
// if let Some(double_indirect_block) =
// self.get_block::<DoubleIndirectBlock>(inode.double_indirect as usize)
// {
// // 取出 double indirect block
// let indirect_block_index = double_indirect_block.block.indirect
// [block_index_within_inode / INODE_PER_BLOCK]
// as usize;
// // 要找的 entry 在 double indirect block 中的第几个 indirect block
// if let Some(indirect_block) = self.get_block::<IndirectBlock>(indirect_block_index)
// {
// let block_index = indirect_block.block.entries
// [block_index_within_inode % INODE_PER_BLOCK]
// as usize;
// // 拿到 DirectoryBlock 的 index
// return self
// .get_block::<DirectoryBlock>(block_index)
// .map(|inode_block| {
// inode_block.block.entries[entry_index_within_block].clone()
// });
// }
// }
// return None;
// } else {
// block_index_within_inode -= double_indirect_number;
// }
//
// // triple indirect block
// if let Some(triple_indirect_block) =
// self.get_block::<TripleIndirectBlock>(inode.triple_indirect as usize)
// {
// // 取出 triple indirect block
// let double_indirect_block_index = triple_indirect_block.block.double_indirect
// [block_index_within_inode / (INODE_PER_BLOCK * INODE_PER_BLOCK)]
// as usize;
// // 要找的 entry 在 triple indirect block 中的第几个 double indirect block
// if let Some(double_indirect_block) =
// self.get_block::<DoubleIndirectBlock>(double_indirect_block_index)
// {
// // 取出 double indirect block
// let indirect_block_index = double_indirect_block.block.indirect
// [block_index_within_inode % (INODE_PER_BLOCK * INODE_PER_BLOCK)
// / INODE_PER_BLOCK] as usize;
// // 要找的 entry 在 double indirect block 中的第几个 indirect block
// if let Some(indirect_block) = self.get_block::<IndirectBlock>(indirect_block_index)
// {
// let block_index = indirect_block.block.entries
// [block_index_within_inode % INODE_PER_BLOCK]
// as usize;
// // DirectoryBlock 的 index
// return self
// .get_block::<DirectoryBlock>(block_index)
// .map(|inode_block| {
// inode_block.block.entries[entry_index_within_block].clone()
// });
// }
// }
// }
// None
// }
// TODO 实现一个带 cache 的版本
pub fn lookup_name(&mut self, parent_inode: &Inode, name: &OsStr) -> Result<(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, inode))
}
}
entry_index += 1;
}
Err(ENOENT)
}
}
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