Add Deref implementation for HSTRING

crates/libs/result/src/bstr.rs

@@ -1,36 +1,26 @@
 use super::*;
+use core::ops::Deref;
 
 #[repr(transparent)]
 pub struct BasicString(*const u16);
 
-impl BasicString {
- pub fn is_empty(&self) -> bool {
- self.len() == 0
- }
+impl Deref for BasicString {
+ type Target = [u16];
 
- pub fn len(&self) -> usize {
- if self.0.is_null() {
+ fn deref(&self) -> &[u16] {
+ let len = if self.0.is_null() {
  0
  } else {
  unsafe { SysStringLen(self.0) as usize }
- }
- }
-
- pub fn as_wide(&self) -> &[u16] {
- let len = self.len();
- if len != 0 {
- unsafe { core::slice::from_raw_parts(self.as_ptr(), len) }
- } else {
- &[]
- }
- }
+ };
 
- pub fn as_ptr(&self) -> *const u16 {
- if !self.is_empty() {
- self.0
+ if len > 0 {
+ unsafe { core::slice::from_raw_parts(self.0, len) }
  } else {
+ // This ensures that if `as_ptr` is called on the slice that the resulting pointer
+ // will still refer to a null-terminated string.
  const EMPTY: [u16; 1] = [0];
- EMPTY.as_ptr()
+ &EMPTY[..0]
  }
  }
 }

crates/libs/result/src/error.rs

@@ -343,7 +343,7 @@ mod error_info {
  }
  }
 
- Some(String::from_utf16_lossy(wide_trim_end(message.as_wide())))
+ Some(String::from_utf16_lossy(wide_trim_end(&message)))
  }
 
  pub(crate) fn as_ptr(&self) -> *mut core::ffi::c_void {

crates/libs/strings/src/bstr.rs

@@ -1,4 +1,5 @@
 use super::*;
+use core::ops::Deref;
 
 /// A BSTR string ([BSTR](https://learn.microsoft.com/en-us/previous-versions/windows/desktop/automat/string-manipulation-functions))
 /// is a length-prefixed wide string.
@@ -13,35 +14,6 @@ impl BSTR {
  Self(core::ptr::null_mut())
  }
 
- /// Returns `true` if the string is empty.
- pub fn is_empty(&self) -> bool {
- self.len() == 0
- }
-
- /// Returns the length of the string.
- pub fn len(&self) -> usize {
- if self.0.is_null() {
- 0
- } else {
- unsafe { bindings::SysStringLen(self.0) as usize }
- }
- }
-
- /// Get the string as 16-bit wide characters (wchars).
- pub fn as_wide(&self) -> &[u16] {
- unsafe { core::slice::from_raw_parts(self.as_ptr(), self.len()) }
- }
-
- /// Returns a raw pointer to the `BSTR` buffer.
- pub fn as_ptr(&self) -> *const u16 {
- if !self.is_empty() {
- self.0
- } else {
- const EMPTY: [u16; 1] = [0];
- EMPTY.as_ptr()
- }
- }
-
  /// Create a `BSTR` from a slice of 16 bit characters (wchars).
  pub fn from_wide(value: &[u16]) -> Self {
  if value.is_empty() {
@@ -75,9 +47,30 @@ impl BSTR {
  }
 }
 
+impl Deref for BSTR {
+ type Target = [u16];
+
+ fn deref(&self) -> &[u16] {
+ let len = if self.0.is_null() {
+ 0
+ } else {
+ unsafe { bindings::SysStringLen(self.0) as usize }
+ };
+
+ if len > 0 {
+ unsafe { core::slice::from_raw_parts(self.0, len) }
+ } else {
+ // This ensures that if `as_ptr` is called on the slice that the resulting pointer
+ // will still refer to a null-terminated string.
+ const EMPTY: [u16; 1] = [0];
+ &EMPTY[..0]
+ }
+ }
+}
+
 impl Clone for BSTR {
  fn clone(&self) -> Self {
- Self::from_wide(self.as_wide())
+ Self::from_wide(self)
  }
 }
 
@@ -104,7 +97,7 @@ impl<'a> TryFrom<&'a BSTR> for String {
  type Error = alloc::string::FromUtf16Error;
 
  fn try_from(value: &BSTR) -> core::result::Result<Self, Self::Error> {
- String::from_utf16(value.as_wide())
+ String::from_utf16(value)
  }
 }
 
@@ -127,7 +120,7 @@ impl core::fmt::Display for BSTR {
  core::write!(
  f,
  "{}",
- Decode(|| core::char::decode_utf16(self.as_wide().iter().cloned()))
+ Decode(|| core::char::decode_utf16(self.iter().cloned()))
  )
  }
 }
@@ -140,7 +133,7 @@ impl core::fmt::Debug for BSTR {
 
 impl PartialEq for BSTR {
  fn eq(&self, other: &Self) -> bool {
- self.as_wide() == other.as_wide()
+ self.deref() == other.deref()
  }
 }
 
@@ -160,10 +153,7 @@ impl PartialEq<BSTR> for String {
 
 impl<T: AsRef<str> + ?Sized> PartialEq<T> for BSTR {
  fn eq(&self, other: &T) -> bool {
- self.as_wide()
- .iter()
- .copied()
- .eq(other.as_ref().encode_utf16())
+ self.iter().copied().eq(other.as_ref().encode_utf16())
  }
 }
 

crates/libs/strings/src/hstring.rs

@@ -1,4 +1,5 @@
 use super::*;
+use core::ops::Deref;
 
 /// An ([HSTRING](https://docs.microsoft.com/en-us/windows/win32/winrt/hstring))
 /// is a reference-counted and immutable UTF-16 string type.
@@ -13,50 +14,20 @@ impl HSTRING {
  Self(core::ptr::null_mut())
  }
 
- /// Returns `true` if the string is empty.
- pub fn is_empty(&self) -> bool {
- // An empty HSTRING is represented by a null pointer.
- self.0.is_null()
- }
-
- /// Returns the length of the string. The length is measured in `u16`s (UTF-16 code units), not including the terminating null character.
- pub fn len(&self) -> usize {
- if let Some(header) = self.as_header() {
- header.len as usize
- } else {
- 0
- }
- }
-
- /// Get the string as 16-bit wide characters (wchars).
- pub fn as_wide(&self) -> &[u16] {
- unsafe { core::slice::from_raw_parts(self.as_ptr(), self.len()) }
- }
-
- /// Returns a raw pointer to the `HSTRING` buffer.
- pub fn as_ptr(&self) -> *const u16 {
- if let Some(header) = self.as_header() {
- header.data
- } else {
- const EMPTY: [u16; 1] = [0];
- EMPTY.as_ptr()
- }
- }
-
  /// Create a `HSTRING` from a slice of 16 bit characters (wchars).
  pub fn from_wide(value: &[u16]) -> Self {
  unsafe { Self::from_wide_iter(value.iter().copied(), value.len()) }
  }
 
  /// Get the contents of this `HSTRING` as a String lossily.
  pub fn to_string_lossy(&self) -> String {
- String::from_utf16_lossy(self.as_wide())
+ String::from_utf16_lossy(self)
  }
 
  /// Get the contents of this `HSTRING` as a OsString.
  #[cfg(feature = "std")]
  pub fn to_os_string(&self) -> std::ffi::OsString {
- std::os::windows::ffi::OsStringExt::from_wide(self.as_wide())
+ std::os::windows::ffi::OsStringExt::from_wide(self)
  }
 
  /// # Safety
@@ -87,6 +58,21 @@ impl HSTRING {
  }
 }
 
+impl Deref for HSTRING {
+ type Target = [u16];
+
+ fn deref(&self) -> &[u16] {
+ if let Some(header) = self.as_header() {
+ unsafe { core::slice::from_raw_parts(header.data, header.len as usize) }
+ } else {
+ // This ensures that if `as_ptr` is called on the slice that the resulting pointer
+ // will still refer to a null-terminated string.
+ const EMPTY: [u16; 1] = [0];
+ &EMPTY[..0]
+ }
+ }
+}
+
 impl Default for HSTRING {
  fn default() -> Self {
  Self::new()
@@ -125,7 +111,7 @@ impl core::fmt::Display for HSTRING {
  write!(
  f,
  "{}",
- Decode(|| core::char::decode_utf16(self.as_wide().iter().cloned()))
+ Decode(|| core::char::decode_utf16(self.iter().cloned()))
  )
  }
 }
@@ -191,13 +177,13 @@ impl Eq for HSTRING {}
 
 impl Ord for HSTRING {
  fn cmp(&self, other: &Self) -> core::cmp::Ordering {
- self.as_wide().cmp(other.as_wide())
+ self.deref().cmp(other)
  }
 }
 
 impl core::hash::Hash for HSTRING {
  fn hash<H: core::hash::Hasher>(&self, hasher: &mut H) {
- self.as_wide().hash(hasher)
+ self.deref().hash(hasher)
  }
 }
 
@@ -209,7 +195,7 @@ impl PartialOrd for HSTRING {
 
 impl PartialEq for HSTRING {
  fn eq(&self, other: &Self) -> bool {
- *self.as_wide() == *other.as_wide()
+ self.deref() == other.deref()
  }
 }
 
@@ -233,7 +219,7 @@ impl PartialEq<&String> for HSTRING {
 
 impl PartialEq<str> for HSTRING {
  fn eq(&self, other: &str) -> bool {
- self.as_wide().iter().copied().eq(other.encode_utf16())
+ self.iter().copied().eq(other.encode_utf16())
  }
 }
 
@@ -309,8 +295,7 @@ impl PartialEq<&std::ffi::OsString> for HSTRING {
 #[cfg(feature = "std")]
 impl PartialEq<std::ffi::OsStr> for HSTRING {
  fn eq(&self, other: &std::ffi::OsStr) -> bool {
- self.as_wide()
- .iter()
+ self.iter()
  .copied()
  .eq(std::os::windows::ffi::OsStrExt::encode_wide(other))
  }
@@ -376,7 +361,7 @@ impl<'a> TryFrom<&'a HSTRING> for String {
  type Error = alloc::string::FromUtf16Error;
 
  fn try_from(hstring: &HSTRING) -> core::result::Result<Self, Self::Error> {
- String::from_utf16(hstring.as_wide())
+ String::from_utf16(hstring)
  }
 }
 

crates/tests/misc/literals/tests/win.rs

@@ -47,8 +47,6 @@ fn test() {
 fn into() {
  let a = h!("");
  assert!(a.is_empty());
- assert!(!a.as_ptr().is_null());
- assert!(a.as_wide().is_empty());
  let b = PCWSTR(a.as_ptr());
  // Even though an empty HSTRING is internally represented by a null pointer, the PCWSTR
  // will still be a non-null pointer to a null terminated empty string.
@@ -80,7 +78,7 @@ fn assert_hstring(left: &HSTRING, right: &[u16]) {
  unsafe { wcslen(PCWSTR::from_raw(left.as_ptr())) },
  right.len() - 1
  );
- let left = unsafe { std::slice::from_raw_parts(left.as_wide().as_ptr(), right.len()) };
+ let left = unsafe { std::slice::from_raw_parts(left.as_ptr(), right.len()) };
  assert_eq!(left, right);
 }
 

crates/tests/misc/string_param/tests/pwstr.rs

@@ -1,20 +1,4 @@
-use windows::{core::*, Win32::Foundation::*, Win32::UI::Shell::*};
-
-#[test]
-fn error() {
- unsafe {
- SetLastError(ERROR_BUSY_DRIVE);
-
- let utf8 = "test\0".as_bytes();
- let utf16 = HSTRING::from("test\0");
- let utf16 = utf16.as_wide();
- let len = 5;
- assert_eq!(utf8.len(), len);
- assert_eq!(utf16.len(), len);
-
- assert_eq!(GetLastError(), ERROR_BUSY_DRIVE);
- }
-}
+use windows::{core::*, Win32::UI::Shell::*};
 
 #[test]
 fn convert() {