librepcb_rust_core/ffi/
cpp_ffi.rs

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
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
//! FFI for base types

use std::io::{Result, Seek, SeekFrom, Write};
use std::os::raw::c_char;
use std::ptr;

/// cbindgen:no-export
#[doc(hidden)]
pub struct QByteArray;

#[allow(improper_ctypes)]
extern "C" {
  fn ffi_qbytearray_len(obj: &QByteArray) -> usize;
  fn ffi_qbytearray_data(obj: &QByteArray) -> *const u8;
  fn ffi_qbytearray_data_mut(obj: &mut QByteArray) -> *mut u8;
  fn ffi_qbytearray_resize(obj: &mut QByteArray, len: usize, value: u8);
}

/// Convert `QByteArray` to [`Vec<u8>`]
#[allow(dead_code)]
pub fn from_qbytearray(obj: &QByteArray) -> Vec<u8> {
  unsafe {
    let data = ffi_qbytearray_data(obj);
    let len = ffi_qbytearray_len(obj);
    let sl = std::slice::from_raw_parts(data, len);
    sl.to_vec()
  }
}

/// Get the length of a `QByteArray`
#[allow(dead_code)]
pub fn qbytearray_len(obj: &mut QByteArray) -> usize {
  unsafe { ffi_qbytearray_len(obj) }
}

/// Resize a `QByteArray`
#[allow(dead_code)]
pub fn qbytearray_resize(obj: &mut QByteArray, len: usize, value: u8) {
  unsafe {
    ffi_qbytearray_resize(obj, len, value);
  }
}

/// Convert `QByteArray` to [`&[u8]`]
#[allow(dead_code)]
pub fn qbytearray_to_slice(obj: &QByteArray) -> &[u8] {
  unsafe {
    let data = ffi_qbytearray_data(obj);
    let len = ffi_qbytearray_len(obj);
    std::slice::from_raw_parts(data, len)
  }
}

/// Convert `QByteArray` to [`&mut[u8]`]
#[allow(dead_code)]
pub fn qbytearray_to_slice_mut(obj: &mut QByteArray) -> &mut [u8] {
  unsafe {
    let data = ffi_qbytearray_data_mut(obj);
    let len = ffi_qbytearray_len(obj);
    std::slice::from_raw_parts_mut(data, len)
  }
}

/// Helper type which implements the [Write] and [Seek] traits on `QByteArray`
pub struct QByteArrayWriter {
  /// Underlying buffer
  buf: *mut QByteArray,
  /// Current cursor position
  cursor: usize,
}

impl QByteArrayWriter {
  /// Create new writer
  ///
  /// <div class="warning">
  /// The buffer lifetime must not be shorter than the lifetime of the writer!
  /// </div>
  pub fn new(buf: *mut QByteArray) -> Self {
    QByteArrayWriter { buf, cursor: 0 }
  }
}

impl Write for QByteArrayWriter {
  fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
    unsafe {
      let self_buf = self.buf.as_mut().unwrap();
      if self.cursor + buf.len() > qbytearray_len(self_buf) {
        qbytearray_resize(self_buf, self.cursor + buf.len(), 0);
      }
      let ptr = ffi_qbytearray_data_mut(self_buf);
      ptr::copy(buf.as_ptr(), ptr.add(self.cursor), buf.len());
    }
    let bytes_written = buf.len();
    self.cursor += bytes_written;
    Ok(bytes_written)
  }

  fn flush(&mut self) -> Result<()> {
    Ok(())
  }
}

impl Seek for QByteArrayWriter {
  fn seek(&mut self, pos: SeekFrom) -> std::io::Result<u64> {
    unsafe {
      let self_buf = self.buf.as_mut().unwrap();
      let self_buf_len = qbytearray_len(self_buf);
      let new_pos = match pos {
        SeekFrom::Start(offset) => offset as usize,
        SeekFrom::End(offset) => {
          let new_pos = self_buf_len.wrapping_add(offset as usize);
          if new_pos > self_buf_len {
            return Err(std::io::Error::new(
              std::io::ErrorKind::InvalidInput,
              "Seek past end of buffer",
            ));
          }
          new_pos
        }
        SeekFrom::Current(offset) => {
          let new_pos = self.cursor.wrapping_add(offset as usize);
          if new_pos > self_buf_len {
            return Err(std::io::Error::new(
              std::io::ErrorKind::InvalidInput,
              "Seek past end of buffer",
            ));
          }
          new_pos
        }
      };
      self.cursor = new_pos;
    }
    Ok(self.cursor as u64)
  }
}

/// cbindgen:no-export
#[doc(hidden)]
pub struct QString;

#[allow(improper_ctypes)]
extern "C" {
  fn ffi_qstring_len(obj: &QString) -> usize;
  fn ffi_qstring_utf16(obj: &QString) -> *const u16;
  fn ffi_qstring_set(obj: &mut QString, s: *const c_char, len: usize);
}

/// Convert `QString` to [String]
#[allow(dead_code)]
pub fn from_qstring(obj: &QString) -> String {
  unsafe {
    let data = ffi_qstring_utf16(obj);
    let len = ffi_qstring_len(obj);
    // Don't use QString::toUtf8() as it would allocate a temporary QByteArray
    // for the whole string. The approach below avoids this unnecessary copy.
    String::from_utf16_lossy(std::slice::from_raw_parts(data, len))
  }
}

/// Convert [`&str`] to `QString`
#[allow(dead_code)]
pub fn qstring_set(obj: &mut QString, s: &str) {
  unsafe { ffi_qstring_set(obj, s.as_ptr().cast(), s.len()) }
}

/// cbindgen:no-export
#[doc(hidden)]
pub struct QStringList;

#[allow(improper_ctypes)]
extern "C" {
  fn ffi_qstringlist_len(obj: &QStringList) -> usize;
  fn ffi_qstringlist_at(obj: &QStringList, index: usize) -> *const QString;
}

/// Convert `QStringList` to [`Vec<String>`]
#[allow(dead_code)]
pub fn from_qstringlist(obj: &QStringList) -> Vec<String> {
  let mut vec = Vec::new();
  unsafe {
    for i in 0..ffi_qstringlist_len(obj) {
      let s = ffi_qstringlist_at(obj, i);
      assert!(!s.is_null());
      vec.push(from_qstring(&*s));
    }
  }
  vec
}