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#![allow(non_snake_case)]
use crate::co;
use crate::decl::*;
use crate::oleaut::ffi;
/// A
/// [string data type](https://learn.microsoft.com/en-us/previous-versions/windows/desktop/automat/bstr)
/// used with COM automation.
///
/// Automatically calls
/// [`SysFreeString`](https://learn.microsoft.com/en-us/windows/win32/api/oleauto/nf-oleauto-sysfreestring)
/// when the object goes out of scope.
#[repr(transparent)]
pub struct BSTR(*mut u16);
impl Drop for BSTR {
fn drop(&mut self) {
if !self.0.is_null() {
unsafe { ffi::SysFreeString(self.0); }
}
}
}
impl Default for BSTR {
fn default() -> Self {
Self(std::ptr::null_mut())
}
}
impl From<BSTR> for WString {
fn from(v: BSTR) -> WString {
unsafe { WString::from_wchars_nullt(v.as_ptr()) }
}
}
impl std::fmt::Display for BSTR {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
std::fmt::Display::fmt(
unsafe { &WString::from_wchars_nullt(self.as_ptr()) }, f)
}
}
impl std::fmt::Debug for BSTR {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "BSTR \"{}\"", self)
}
}
impl BSTR {
/// [`SysAllocString`](https://learn.microsoft.com/en-us/windows/win32/api/oleauto/nf-oleauto-sysallocstring)
/// function.
#[must_use]
pub fn SysAllocString(s: &str) -> HrResult<Self> {
let str_obj = WString::from_str(s);
let ptr = unsafe { ffi::SysAllocString(str_obj.as_ptr()) };
if ptr.is_null() {
Err(co::HRESULT::E_OUTOFMEMORY)
} else {
Ok(Self(ptr))
}
}
/// [`SysReAllocString`](https://learn.microsoft.com/en-us/windows/win32/api/oleauto/nf-oleauto-sysreallocstring)
/// function.
///
/// The underlying pointer is automatically updated.
pub fn SysReAllocString(&mut self, s: &str) -> HrResult<()> {
let str_obj = WString::from_str(s);
let ptr = unsafe { ffi::SysReAllocString(self.0, str_obj.as_ptr()) };
if ptr.is_null() {
Err(co::HRESULT::E_OUTOFMEMORY)
} else {
self.0 = ptr;
Ok(())
}
}
/// [`SysStringLen`](https://learn.microsoft.com/en-us/windows/win32/api/oleauto/nf-oleauto-sysstringlen)
/// function.
#[must_use]
pub fn SysStringLen(&self) -> u32 {
unsafe { ffi::SysStringLen(self.0) }
}
/// Creates a new `BSTR` by wrapping a pointer.
///
/// # Safety
///
/// Be sure the pointer has the correct type and isn't owned by anyone else,
/// otherwise you may cause memory access violations.
#[must_use]
pub const unsafe fn from_ptr(p: *mut u16) -> Self {
Self(p)
}
/// Returns the underlying
/// [`LPWSTR`](https://learn.microsoft.com/en-us/windows/win32/learnwin32/working-with-strings)
/// pointer to the null-terminated wide string.
#[must_use]
pub const fn as_ptr(&self) -> *mut u16 {
self.0
}
/// Returns the underlying
/// [`LPWSTR`](https://learn.microsoft.com/en-us/windows/win32/learnwin32/working-with-strings)
/// memory block as a null-terminated `u16` slice.
#[must_use]
pub fn as_slice(&self) -> &[u16] {
unsafe {
std::slice::from_raw_parts(self.0, self.SysStringLen() as usize + 1)
}
}
/// Ejects the underlying
/// [`LPWSTR`](https://learn.microsoft.com/en-us/windows/win32/learnwin32/working-with-strings)
/// pointer leaving a null pointer in its place, so that
/// [`SysFreeString`](https://learn.microsoft.com/en-us/windows/win32/api/oleauto/nf-oleauto-sysfreestring)
/// won't be called.
///
/// Be sure to free the pointer, otherwise, as the name of this method
/// implies, you will cause a memory leak.
#[must_use]
pub fn leak(&mut self) -> *mut u16 {
std::mem::replace(&mut self.0, std::ptr::null_mut())
}
}