diff --git a/crates/libs/strings/src/hstring_builder.rs b/crates/libs/strings/src/hstring_builder.rs index 446451f0df..23679bb36a 100644 --- a/crates/libs/strings/src/hstring_builder.rs +++ b/crates/libs/strings/src/hstring_builder.rs @@ -9,7 +9,13 @@ pub struct HStringBuilder(*mut HStringHeader); impl HStringBuilder { /// Creates a preallocated `HSTRING` value. pub fn new(len: usize) -> Result { - Ok(Self(HStringHeader::alloc(len.try_into()?)?)) + let header = HStringHeader::alloc(len.try_into()?)?; + + if len > 0 { + unsafe { core::ptr::write_bytes((*header).data, 0, len) }; + } + + Ok(Self(header)) } /// Shortens the string by removing any trailing 0 characters. diff --git a/crates/libs/strings/src/hstring_header.rs b/crates/libs/strings/src/hstring_header.rs index 84c3851519..dac8760a12 100644 --- a/crates/libs/strings/src/hstring_header.rs +++ b/crates/libs/strings/src/hstring_header.rs @@ -14,18 +14,18 @@ pub struct HStringHeader { } impl HStringHeader { - pub fn alloc(len: u32) -> Result<*mut HStringHeader> { + pub fn alloc(len: u32) -> Result<*mut Self> { if len == 0 { return Ok(core::ptr::null_mut()); } // Allocate enough space for header and two bytes per character. // The space for the terminating null character is already accounted for inside of `HStringHeader`. - let bytes = core::mem::size_of::() + 2 * len as usize; + let bytes = core::mem::size_of::() + 2 * len as usize; #[cfg(windows)] - let header = unsafe { bindings::HeapAlloc(bindings::GetProcessHeap(), 0, bytes) } - as *mut HStringHeader; + let header = + unsafe { bindings::HeapAlloc(bindings::GetProcessHeap(), 0, bytes) } as *mut Self; #[cfg(not(windows))] let header = unsafe { @@ -33,7 +33,7 @@ impl HStringHeader { fn malloc(bytes: usize) -> *mut core::ffi::c_void; } - malloc(bytes) as *mut HStringHeader + malloc(bytes) as *mut Self }; if header.is_null() { @@ -42,7 +42,7 @@ impl HStringHeader { unsafe { // Use `ptr::write` (since `header` is unintialized). `HStringHeader` is safe to be all zeros. - header.write(core::mem::MaybeUninit::::zeroed().assume_init()); + header.write(core::mem::MaybeUninit::::zeroed().assume_init()); (*header).len = len; (*header).count = RefCount::new(1); (*header).data = &mut (*header).buffer_start; @@ -51,17 +51,13 @@ impl HStringHeader { Ok(header) } - pub unsafe fn free(header: *mut HStringHeader) { + pub unsafe fn free(header: *mut Self) { if header.is_null() { return; } - let header = header as *mut _; - #[cfg(windows)] - { - bindings::HeapFree(bindings::GetProcessHeap(), 0, header); - } + bindings::HeapFree(bindings::GetProcessHeap(), 0, header as *mut _); #[cfg(not(windows))] { @@ -69,18 +65,18 @@ impl HStringHeader { fn free(ptr: *mut core::ffi::c_void); } - free(header); + free(header as *mut _); } } - pub fn duplicate(&self) -> Result<*mut HStringHeader> { + pub fn duplicate(&self) -> Result<*mut Self> { if self.flags & HSTRING_REFERENCE_FLAG == 0 { // If this is not a "fast pass" string then simply increment the reference count. self.count.add_ref(); - Ok(self as *const HStringHeader as *mut HStringHeader) + Ok(self as *const Self as *mut Self) } else { // Otherwise, allocate a new string and copy the value into the new string. - let copy = HStringHeader::alloc(self.len)?; + let copy = Self::alloc(self.len)?; // SAFETY: since we are duplicating the string it is safe to copy all data from self to the initialized `copy`. // We copy `len + 1` characters since `len` does not account for the terminating null character. unsafe { diff --git a/crates/tests/strings/tests/hstring.rs b/crates/tests/strings/tests/hstring.rs index 13597f4b90..bb7a35a586 100644 --- a/crates/tests/strings/tests/hstring.rs +++ b/crates/tests/strings/tests/hstring.rs @@ -47,5 +47,9 @@ fn hstring_builder() -> Result<()> { assert_eq!(h.len(), 5); assert_eq!(h.as_wide(), HELLO); + // HStringBuilder will initialize memory to zero. + let b = HStringBuilder::new(5)?; + assert_eq!(*b, [0, 0, 0, 0, 0]); + Ok(()) }