winit/src/platform_impl/linux/x11/util/window_property.rs
2022-07-15 18:32:12 +02:00

142 lines
4.6 KiB
Rust

use super::*;
pub type Cardinal = c_long;
pub const CARDINAL_SIZE: usize = mem::size_of::<c_long>();
#[derive(Debug, Clone)]
pub enum GetPropertyError {
XError(XError),
TypeMismatch(ffi::Atom),
FormatMismatch(c_int),
NothingAllocated,
}
impl GetPropertyError {
pub fn is_actual_property_type(&self, t: ffi::Atom) -> bool {
if let GetPropertyError::TypeMismatch(actual_type) = *self {
actual_type == t
} else {
false
}
}
}
// Number of 32-bit chunks to retrieve per iteration of get_property's inner loop.
// To test if `get_property` works correctly, set this to 1.
const PROPERTY_BUFFER_SIZE: c_long = 1024; // 4k of RAM ought to be enough for anyone!
#[derive(Debug)]
#[allow(dead_code)]
pub enum PropMode {
Replace = ffi::PropModeReplace as isize,
Prepend = ffi::PropModePrepend as isize,
Append = ffi::PropModeAppend as isize,
}
impl XConnection {
pub fn get_property<T: Formattable>(
&self,
window: c_ulong,
property: ffi::Atom,
property_type: ffi::Atom,
) -> Result<Vec<T>, GetPropertyError> {
let mut data = Vec::new();
let mut offset = 0;
let mut done = false;
let mut actual_type = 0;
let mut actual_format = 0;
let mut quantity_returned = 0;
let mut bytes_after = 0;
let mut buf: *mut c_uchar = ptr::null_mut();
while !done {
unsafe {
(self.xlib.XGetWindowProperty)(
self.display,
window,
property,
// This offset is in terms of 32-bit chunks.
offset,
// This is the quantity of 32-bit chunks to receive at once.
PROPERTY_BUFFER_SIZE,
ffi::False,
property_type,
&mut actual_type,
&mut actual_format,
// This is the quantity of items we retrieved in our format, NOT of 32-bit chunks!
&mut quantity_returned,
// ...and this is a quantity of bytes. So, this function deals in 3 different units.
&mut bytes_after,
&mut buf,
);
if let Err(e) = self.check_errors() {
return Err(GetPropertyError::XError(e));
}
if actual_type != property_type {
return Err(GetPropertyError::TypeMismatch(actual_type));
}
let format_mismatch = Format::from_format(actual_format as _) != Some(T::FORMAT);
if format_mismatch {
return Err(GetPropertyError::FormatMismatch(actual_format));
}
if !buf.is_null() {
offset += PROPERTY_BUFFER_SIZE;
let new_data =
std::slice::from_raw_parts(buf as *mut T, quantity_returned as usize);
/*println!(
"XGetWindowProperty prop:{:?} fmt:{:02} len:{:02} off:{:02} out:{:02}, buf:{:?}",
property,
mem::size_of::<T>() * 8,
data.len(),
offset,
quantity_returned,
new_data,
);*/
data.extend_from_slice(new_data);
// Fun fact: XGetWindowProperty allocates one extra byte at the end.
(self.xlib.XFree)(buf as _); // Don't try to access new_data after this.
} else {
return Err(GetPropertyError::NothingAllocated);
}
done = bytes_after == 0;
}
}
Ok(data)
}
pub fn change_property<'a, T: Formattable>(
&'a self,
window: c_ulong,
property: ffi::Atom,
property_type: ffi::Atom,
mode: PropMode,
new_value: &[T],
) -> Flusher<'a> {
debug_assert_eq!(mem::size_of::<T>(), T::FORMAT.get_actual_size());
unsafe {
(self.xlib.XChangeProperty)(
self.display,
window,
property,
property_type,
T::FORMAT as c_int,
mode as c_int,
new_value.as_ptr() as *const c_uchar,
new_value.len() as c_int,
);
}
/*println!(
"XChangeProperty prop:{:?} val:{:?}",
property,
new_value,
);*/
Flusher::new(self)
}
}