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/* libguestfs Rust bindings
* Copyright (C) 2019 Hiroyuki Katsura <hiroyuki.katsura.0513@gmail.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
use crate::base;
use crate::error;
use crate::guestfs;
use crate::utils;
use std::os::raw::{c_char, c_void};
use std::slice;
type GuestfsEventCallback = extern "C" fn(
*const base::guestfs_h,
*const c_void,
u64,
i32,
i32,
*const i8,
usize,
*const u64,
usize,
);
#[link(name = "guestfs")]
extern "C" {
fn guestfs_set_event_callback(
g: *const base::guestfs_h,
cb: GuestfsEventCallback,
event_bitmask: u64,
flags: i32,
opaque: *const c_void,
) -> i32;
fn guestfs_delete_event_callback(g: *const base::guestfs_h, eh: i32);
fn guestfs_event_to_string(bitmask: u64) -> *const c_char;
fn free(buf: *const c_void);
}
#[derive(Hash, PartialEq, Eq)]
pub struct EventHandle {
eh: i32,
}
fn events_to_bitmask(v: &[guestfs::Event]) -> u64 {
let mut r = 0u64;
for x in v.iter() {
r |= x.to_u64();
}
r
}
pub fn event_to_string(events: &[guestfs::Event]) -> Result<String, error::Error> {
let bitmask = events_to_bitmask(events);
let r = unsafe { guestfs_event_to_string(bitmask) };
if r.is_null() {
Err(error::unix_error("event_to_string"))
} else {
let s = unsafe { utils::char_ptr_to_string(r) };
unsafe { free(r as *const c_void) };
Ok(s?)
}
}
impl<'a> base::Handle<'a> {
pub fn set_event_callback<C: 'a>(
&mut self,
callback: C,
events: &[guestfs::Event],
) -> Result<EventHandle, error::Error>
where
C: Fn(guestfs::Event, EventHandle, &[u8], &[u64]) + 'a,
{
extern "C" fn trampoline<C>(
_g: *const base::guestfs_h,
opaque: *const c_void,
event: u64,
event_handle: i32,
_flags: i32,
buf: *const c_char,
buf_len: usize,
array: *const u64,
array_len: usize,
) where
C: Fn(guestfs::Event, EventHandle, &[u8], &[u64]),
{
// trampoline function
// c.f. https://s3.amazonaws.com/temp.michaelfbryan.com/callbacks/index.html
let event = match guestfs::Event::from_bitmask(event) {
Some(x) => x,
None => panic!("Failed to parse bitmask: {}", event),
};
let eh = EventHandle { eh: event_handle };
let buf = unsafe { slice::from_raw_parts(buf as *const u8, buf_len) };
let array = unsafe { slice::from_raw_parts(array, array_len) };
let callback: &Box<dyn Fn(guestfs::Event, EventHandle, &[u8], &[u64])> =
Box::leak(unsafe { Box::from_raw(opaque as *mut _) });
callback(event, eh, buf, array)
}
// Because trait pointer is fat pointer, in order to pass it to API,
// double Box is used.
let callback: Box<Box<dyn Fn(guestfs::Event, EventHandle, &[u8], &[u64]) + 'a>> =
Box::new(Box::new(callback));
let ptr = Box::into_raw(callback);
let callback = unsafe { Box::from_raw(ptr) };
let event_bitmask = events_to_bitmask(events);
let eh = {
unsafe {
guestfs_set_event_callback(
self.g,
trampoline::<C>,
event_bitmask,
0,
ptr as *const c_void,
)
}
};
if eh == -1 {
return Err(self.get_error_from_handle("set_event_callback"));
}
self.callbacks.insert(EventHandle { eh }, callback);
Ok(EventHandle { eh })
}
pub fn delete_event_callback(&mut self, eh: EventHandle) -> Result<(), error::Error> {
unsafe {
guestfs_delete_event_callback(self.g, eh.eh);
}
self.callbacks.remove(&eh);
Ok(())
}
}
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