1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139

use super::File;
use crate::drivers::BLOCK_DEVICE;
use crate::mm::UserBuffer;
use crate::sync::UPSafeCell;
use alloc::sync::Arc;
use alloc::vec::Vec;
use bitflags::*;
use easy_fs::{EasyFileSystem, Inode};
use lazy_static::*;

pub struct OSInode {
    readable: bool,
    writable: bool,
    inner: UPSafeCell<OSInodeInner>,
}

pub struct OSInodeInner {
    offset: usize,
    inode: Arc<Inode>,
}

impl OSInode {
    pub fn new(readable: bool, writable: bool, inode: Arc<Inode>) -> Self {
        Self {
            readable,
            writable,
            inner: unsafe { UPSafeCell::new(OSInodeInner { offset: 0, inode }) },
        }
    }
    pub fn read_all(&self) -> Vec<u8> {
        let mut inner = self.inner.exclusive_access();
        let mut buffer = [0u8; 512];
        let mut v: Vec<u8> = Vec::new();
        loop {
            let len = inner.inode.read_at(inner.offset, &mut buffer);
            if len == 0 {
                break;
            }
            inner.offset += len;
            v.extend_from_slice(&buffer[..len]);
        }
        v
    }
}

lazy_static! {
    pub static ref ROOT_INODE: Arc<Inode> = {
        let efs = EasyFileSystem::open(BLOCK_DEVICE.clone());
        Arc::new(EasyFileSystem::root_inode(&efs))
    };
}

pub fn list_apps() {
    println!("/**** APPS ****");
    for app in ROOT_INODE.ls() {
        println!("{}", app);
    }
    println!("**************/");
}

bitflags! {
    pub struct OpenFlags: u32 {
        const RDONLY = 0;
        const WRONLY = 1 << 0;
        const RDWR = 1 << 1;
        const CREATE = 1 << 9;
        const TRUNC = 1 << 10;
    }
}

impl OpenFlags {
    /// Do not check validity for simplicity
    /// Return (readable, writable)
    pub fn read_write(&self) -> (bool, bool) {
        if self.is_empty() {
            (true, false)
        } else if self.contains(Self::WRONLY) {
            (false, true)
        } else {
            (true, true)
        }
    }
}

pub fn open_file(name: &str, flags: OpenFlags) -> Option<Arc<OSInode>> {
    let (readable, writable) = flags.read_write();
    if flags.contains(OpenFlags::CREATE) {
        if let Some(inode) = ROOT_INODE.find(name) {
            // clear size
            inode.clear();
            Some(Arc::new(OSInode::new(readable, writable, inode)))
        } else {
            // create file
            ROOT_INODE
                .create(name)
                .map(|inode| Arc::new(OSInode::new(readable, writable, inode)))
        }
    } else {
        ROOT_INODE.find(name).map(|inode| {
            if flags.contains(OpenFlags::TRUNC) {
                inode.clear();
            }
            Arc::new(OSInode::new(readable, writable, inode))
        })
    }
}

impl File for OSInode {
    fn readable(&self) -> bool {
        self.readable
    }
    fn writable(&self) -> bool {
        self.writable
    }
    fn read(&self, mut buf: UserBuffer) -> usize {
        let mut inner = self.inner.exclusive_access();
        let mut total_read_size = 0usize;
        for slice in buf.buffers.iter_mut() {
            let read_size = inner.inode.read_at(inner.offset, *slice);
            if read_size == 0 {
                break;
            }
            inner.offset += read_size;
            total_read_size += read_size;
        }
        total_read_size
    }
    fn write(&self, buf: UserBuffer) -> usize {
        let mut inner = self.inner.exclusive_access();
        let mut total_write_size = 0usize;
        for slice in buf.buffers.iter() {
            let write_size = inner.inode.write_at(inner.offset, *slice);
            assert_eq!(write_size, slice.len());
            inner.offset += write_size;
            total_write_size += write_size;
        }
        total_write_size
    }
}