std\backtrace\src\symbolize\gimli/
mmap_windows.rs

1use super::super::super::windows_sys::*;
2
3use super::mystd::fs::File;
4use super::mystd::os::windows::prelude::*;
5use core::ffi::c_void;
6use core::ops::Deref;
7use core::ptr;
8use core::slice;
9
10pub struct Mmap {
11    // keep the file alive to prevent it from being deleted which would cause
12    // us to read bad data.
13    _file: File,
14    ptr: *mut c_void,
15    len: usize,
16}
17
18impl Mmap {
19    pub unsafe fn map(file: &File, len: usize, offset: u64) -> Option<Mmap> {
20        unsafe {
21            let file = file.try_clone().ok()?;
22            let mapping = CreateFileMappingA(
23                file.as_raw_handle(),
24                ptr::null_mut(),
25                PAGE_READONLY,
26                0,
27                0,
28                ptr::null(),
29            );
30            if mapping.is_null() {
31                return None;
32            }
33            let ptr = MapViewOfFile(
34                mapping,
35                FILE_MAP_READ,
36                (offset >> 32) as u32,
37                offset as u32,
38                len,
39            );
40            CloseHandle(mapping);
41            if ptr.Value.is_null() {
42                return None;
43            }
44            Some(Mmap {
45                _file: file,
46                ptr: ptr.Value,
47                len,
48            })
49        }
50    }
51}
52impl Deref for Mmap {
53    type Target = [u8];
54
55    fn deref(&self) -> &[u8] {
56        unsafe { slice::from_raw_parts(self.ptr.cast_const().cast::<u8>(), self.len) }
57    }
58}
59
60impl Drop for Mmap {
61    fn drop(&mut self) {
62        unsafe {
63            let r = UnmapViewOfFile(MEMORY_MAPPED_VIEW_ADDRESS { Value: self.ptr });
64            debug_assert!(r != 0);
65        }
66    }
67}