winctx 0.0.20

A minimal window context for Rust on Windows.
Documentation 
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
143
144
145
146
147
148
149
150
151
152
153
154

use std::ffi::OsStr;
use std::fmt;
use std::io;
use std::ptr;

use windows_sys::Win32::Foundation::HWND;
use windows_sys::Win32::System::DataExchange::COPYDATASTRUCT;
use windows_sys::Win32::UI::WindowsAndMessaging::FindWindowExW;
use windows_sys::Win32::UI::WindowsAndMessaging::SendMessageW;
use windows_sys::Win32::UI::WindowsAndMessaging::WM_COPYDATA;

use crate::convert::ToWide;

/// Helper to find windows by title or class.
#[derive(Default)]
pub struct FindWindow {
    class: Option<Vec<u16>>,
    title: Option<Vec<u16>>,
}

impl FindWindow {
    /// Creates a blank find window query.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use winctx::window::FindWindow;
    ///
    /// let mut options = FindWindow::new().class("se.tedro.Example");
    /// ```
    #[inline]
    pub fn new() -> Self {
        Self::default()
    }

    /// Find window by the specified class name.
    ///
    /// The `class` argument matches what has been provided to
    /// [`CreateWindow::new`].
    ///
    /// [`CreateWindow::new`]: crate::CreateWindow::new
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use winctx::window::FindWindow;
    ///
    /// let window = FindWindow::new().class("se.tedro.Example").find()?;
    /// # Ok::<_, std::io::Error>(())
    /// ```
    pub fn class<C>(&mut self, class: C) -> &mut Self
    where
        C: AsRef<OsStr>,
    {
        self.class = Some(class.as_ref().to_wide_null());
        self
    }

    /// Find window by the specified class name.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use winctx::window::FindWindow;
    ///
    /// let window = FindWindow::new().title("Example Application").find()?;
    /// # Ok::<_, std::io::Error>(())
    /// ```
    pub fn title<T>(&mut self, title: T) -> &mut Self
    where
        T: AsRef<OsStr>,
    {
        self.title = Some(title.as_ref().to_wide_null());
        self
    }

    /// Construct an iterator over all matching windows.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use winctx::window::FindWindow;
    ///
    /// let window = FindWindow::new().class("se.tedro.Example").find()?;
    /// # Ok::<_, std::io::Error>(())
    /// ```
    pub fn find(&self) -> io::Result<Option<Window>> {
        // SAFETY: All arguments are correctly popuplated by this builder.
        unsafe {
            let hwnd = FindWindowExW(
                ptr::null_mut(),
                ptr::null_mut(),
                self.class.as_ref().map_or(ptr::null(), |c| c.as_ptr()),
                self.title.as_ref().map_or(ptr::null(), |c| c.as_ptr()),
            );

            if hwnd.is_null() {
                return Err(io::Error::last_os_error());
            }

            Ok(Some(Window { hwnd }))
        }
    }
}

/// Handle to a window on the system.
pub struct Window {
    hwnd: HWND,
}

impl Window {
    /// Copy bytes to the given process.
    ///
    /// Data is received as an [`Event::CopyData`] event.
    ///
    /// [`Event::CopyData`]: crate::Event::CopyData
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use winctx::window::FindWindow;
    ///
    /// let Some(window) = FindWindow::new().class("se.tedro.Example").find()? else {
    ///     println!("Could not find window");
    ///     return Ok(());
    /// };
    ///
    /// window.copy_data(42, b"foobar")?;
    /// # Ok::<_, std::io::Error>(())
    /// ```
    pub fn copy_data(&self, ty: usize, bytes: &[u8]) -> io::Result<()> {
        // SAFETY: All arguments are correctly popuplated by this builder.
        unsafe {
            let data = COPYDATASTRUCT {
                dwData: ty,
                cbData: bytes.len() as u32,
                lpData: (bytes.as_ptr() as *mut u8).cast(),
            };

            SendMessageW(self.hwnd, WM_COPYDATA, 0, &data as *const _ as isize);
            Ok(())
        }
    }
}

impl fmt::Debug for Window {
    #[inline]
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Window").field("hwnd", &self.hwnd).finish()
    }
}

unsafe impl Send for Window {}
unsafe impl Sync for Window {}