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
140
141
142

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)
    }
}