1 files changed, 92 insertions, 0 deletions
diff --git a/ayafs/src/utils/mod.rs b/ayafs/src/utils/mod.rs
new file mode 100644
index 0000000..468ebdb
--- /dev/null
+++ b/ayafs/src/utils/mod.rs
@@ -0,0 +1,92 @@
+mod constants;
+pub mod permissions;
+
+use crate::block_device::BLOCK_SIZE;
+use crate::disk::inode::{Inode, INODE_SIZE};
+use crate::{AyaFS, INODE_PER_BLOCK};
+use fuser::{FileAttr, FileType};
+use std::time::{Duration, SystemTime, UNIX_EPOCH};
+
+pub(crate) fn time_now() -> u32 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .expect("How can current time be earlier than UNIX_EPOCH?")
+        .as_secs() as u32
+}
+
+pub(crate) fn from_systime(system_time: SystemTime) -> u32 {
+    system_time
+        .duration_since(UNIX_EPOCH)
+        .expect("How can current time be earlier than UNIX_EPOCH?")
+        .as_secs() as u32
+}
+
+pub(crate) fn to_systime(time: u32) -> SystemTime {
+    UNIX_EPOCH + Duration::from_secs(time as u64)
+}
+
+// File type code, one of:
+// 0x0 	Unknown.
+// 0x1 	Regular file.
+// 0x2 	Directory.
+// 0x3 	Character device file.
+// 0x4 	Block device file.
+// 0x5 	FIFO.
+// 0x6 	Socket.
+// 0x7 	Symbolic link.
+
+pub(crate) fn from_filetype(file_type: FileType) -> u8 {
+    match file_type {
+        FileType::NamedPipe => 0x5,
+        FileType::CharDevice => 0x3,
+        FileType::BlockDevice => 0x4,
+        FileType::Directory => 0x2,
+        FileType::RegularFile => 0x1,
+        FileType::Symlink => 0x7,
+        FileType::Socket => 0x6,
+    }
+}
+
+pub(crate) fn to_filetype(file_type: u8) -> Option<FileType> {
+    match file_type {
+        0x0 => None,
+        0x1 => Some(FileType::RegularFile),
+        0x2 => Some(FileType::Directory),
+        0x3 => Some(FileType::CharDevice),
+        0x4 => Some(FileType::BlockDevice),
+        0x5 => Some(FileType::NamedPipe),
+        0x6 => Some(FileType::Socket),
+        0x7 => Some(FileType::Symlink),
+        _ => panic!("bad filetype"),
+    }
+}
+
+pub(crate) fn to_fileattr(inode_index: usize, inode: &Inode) -> FileAttr {
+    FileAttr {
+        ino: inode_index as u64,
+        size: inode.size as u64,
+        blocks: inode.n_blocks as u64,
+        atime: to_systime(inode.atime),
+        mtime: to_systime(inode.mtime),
+        ctime: to_systime(inode.ctime),
+        crtime: to_systime(inode.crtime),
+        kind: inode.mode.into(),
+        perm: inode.mode.perm(),
+        nlink: inode.n_links as u32,
+        uid: inode.uid,
+        gid: inode.gid,
+        rdev: 0,
+        blksize: BLOCK_SIZE as u32,
+        flags: inode.flags,
+    }
+}
+
+impl AyaFS {
+    /// 输入 inode 编号, 返回它对应的 block number 和 block 内 offset
+    pub(crate) fn locate_inode(&self, inode_index: usize) -> (usize, usize) {
+        let block_number =
+            inode_index / INODE_PER_BLOCK + 1 + self.inode_bitmap.length + self.data_bitmap.length;
+        let block_offset = inode_index % INODE_PER_BLOCK * INODE_SIZE;
+        (block_number, block_offset)
+    }
+}