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src/pxar/fuse.rs: Refactor run_in_context and remove inode_to_offset and offset_to_inode 

as their functionality is used only once so it makes more sense to keep them
inline.

Signed-off-by: Christian Ebner <c.ebner@proxmox.com>
This commit is contained in:
Christian Ebner 2019-09-06 11:38:27 +02:00 committed by Dietmar Maurer
parent 8413083fc5
commit ec04ea81f2
1 changed files with 27 additions and 48 deletions
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75
src/pxar/fuse.rs
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@ -27,6 +27,7 @@ use super::format_definition::PxarGoodbyeItem;
/// required. /// required.
const FUSE_ROOT_ID: u64 = 1; const FUSE_ROOT_ID: u64 = 1;
const GOODBYE_ITEM_SIZE: u64 = std::mem::size_of::<PxarGoodbyeItem>() as u64;
/// Callback function for `super::decoder::Decoder`. /// Callback function for `super::decoder::Decoder`.
/// ///
/// At the moment, this is only needed to satisfy the `SequentialDecoder`. /// At the moment, this is only needed to satisfy the `SequentialDecoder`.
@ -252,47 +253,19 @@ impl Drop for Session {
} }
} }
const GOODBYE_ITEM_SIZE: u64 = std::mem::size_of::<PxarGoodbyeItem>() as u64;
/// Converts the inode to the file offset
///
/// Since the inodes are defined as the file offset,
/// this simply returns the inode value.
/// The only exception to this is the inode of root,
/// which is defined as `FUSE_ROOT_ID` by libfuse and therefore mapped
/// to the roots goodbye table tail.
fn inode_to_offset(inode: u64, root_end: u64) -> u64 {
if inode == FUSE_ROOT_ID {
root_end - GOODBYE_ITEM_SIZE
} else {
inode
}
}
/// Converts the file offset to an inode
///
/// Since the inodes are defined as the file offset,
/// this simply returns the offset value.
/// The only exception to this is the inode of root,
/// which is defined as `FUSE_ROOT_ID` by libfuse, so the roots goodbye tail
/// offset gets mapped to `FUSE_ROOT_ID`.
pub(crate) fn offset_to_inode(offset: u64, root_end: u64) -> u64 {
if offset == root_end - GOODBYE_ITEM_SIZE {
FUSE_ROOT_ID
} else {
offset
}
}
/// Creates a context providing an exclusive mutable reference to the decoder. /// Creates a context providing an exclusive mutable reference to the decoder.
/// ///
/// Each callback function needing access to the decoder can easily get an /// Each callback function needing access to the decoder can easily get an
/// exclusive handle by running the code inside this context. /// exclusive handle by running the code inside this context.
/// Responses with error code can easily be generated by returning with the /// Responses with error code can easily be generated by returning with the
/// error code. /// error code.
fn run_in_context<F>(req: Request, code: F) /// The error code will be used to reply to libfuse.
fn run_in_context<F>(req: Request, inode: u64, code: F)
where where
F: FnOnce(&mut Decoder<BufReader<File>, fn(&Path) -> Result<(), Error>>) -> Result<(), i32>, F: FnOnce(
&mut Decoder<BufReader<File>, fn(&Path) -> Result<(), Error>>,
u64,
) -> Result<(), i32>,
{ {
let ptr = unsafe { let ptr = unsafe {
fuse_req_userdata(req) fuse_req_userdata(req)
@ -301,8 +274,14 @@ where
let boxed_decoder = unsafe { Box::from_raw(ptr) }; let boxed_decoder = unsafe { Box::from_raw(ptr) };
let result = boxed_decoder let result = boxed_decoder
.lock() .lock()
.map(|mut decoder| code(&mut decoder)) .map(|mut decoder| {
.unwrap_or(Err(libc::ENOENT)); let ino_offset = match inode {
FUSE_ROOT_ID => decoder.root_end_offset() - GOODBYE_ITEM_SIZE,
_ => inode,
};
code(&mut decoder, ino_offset)
})
.unwrap_or(Err(libc::EIO));
if let Err(err) = result { if let Err(err) = result {
unsafe { unsafe {
@ -327,48 +306,48 @@ extern "C" fn destroy(decoder: MutPtr) {
} }
} }
extern "C" fn lookup(req: Request, _parent: u64, _name: StrPtr) { extern "C" fn lookup(req: Request, parent: u64, _name: StrPtr) {
run_in_context(req, |_decoder| { run_in_context(req, parent, |_decoder, _ino_offset| {
// code goes here // code goes here
Err(libc::ENOENT) Err(libc::ENOENT)
}); });
} }
extern "C" fn getattr(req: Request, _inode: u64, _fileinfo: MutPtr) { extern "C" fn getattr(req: Request, inode: u64, _fileinfo: MutPtr) {
run_in_context(req, |_decoder| { run_in_context(req, inode, |_decoder, _ino_offset| {
// code goes here // code goes here
Err(libc::ENOENT) Err(libc::ENOENT)
}); });
} }
extern "C" fn open(req: Request, _inode: u64, _fileinfo: MutPtr) { extern "C" fn open(req: Request, inode: u64, _fileinfo: MutPtr) {
run_in_context(req, |_decoder| { run_in_context(req, inode, |_decoder, _ino_offset| {
// code goes here // code goes here
Err(libc::ENOENT) Err(libc::ENOENT)
}); });
} }
extern "C" fn read(req: Request, _inode: u64, _size: size_t, _offset: c_int, _fileinfo: MutPtr) { extern "C" fn read(req: Request, inode: u64, _size: size_t, _offset: c_int, _fileinfo: MutPtr) {
run_in_context(req, |_decoder| { run_in_context(req, inode, |_decoder, _ino_offset| {
// code goes here // code goes here
Err(libc::ENOENT) Err(libc::ENOENT)
}); });
} }
extern "C" fn opendir(req: Request, _inode: u64, _fileinfo: MutPtr) { extern "C" fn opendir(req: Request, inode: u64, _fileinfo: MutPtr) {
run_in_context(req, |_decoder| { run_in_context(req, inode, |_decoder, _ino_offset| {
// code goes here // code goes here
Err(libc::ENOENT) Err(libc::ENOENT)
}); });
} }
extern "C" fn readdir(req: Request, _inode: u64, _size: size_t, _offset: c_int, _fileinfo: MutPtr) { extern "C" fn readdir(req: Request, inode: u64, _size: size_t, _offset: c_int, _fileinfo: MutPtr) {
run_in_context(req, |_decoder| { run_in_context(req, inode, |_decoder, _ino_offset| {
// code goes here // code goes here
Err(libc::ENOENT) Err(libc::ENOENT)