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Diffstat (limited to 'xpcom/rust/nsstring/src/lib.rs')
| -rw-r--r-- | xpcom/rust/nsstring/src/lib.rs | 853 |
1 files changed, 0 insertions, 853 deletions
diff --git a/xpcom/rust/nsstring/src/lib.rs b/xpcom/rust/nsstring/src/lib.rs deleted file mode 100644 index cd518f3c5..000000000 --- a/xpcom/rust/nsstring/src/lib.rs +++ /dev/null @@ -1,853 +0,0 @@ -//! This module provides rust bindings for the XPCOM string types. -//! -//! # TL;DR (what types should I use) -//! -//! Use `&{mut,} nsA[C]String` for functions in rust which wish to take or -//! mutate XPCOM strings. The other string types `Deref` to this type. -//! -//! Use `ns[C]String<'a>` for string struct members which don't leave rust, and -//! as an intermediate between rust string data structures (such as `String`, -//! `Vec<u16>`, `&str`, and `&[u16]`) and `&{mut,} nsA[C]String` (using -//! `ns[C]String::from(value)`). These conversions, when possible, will not -//! perform any allocations. -//! -//! Use `nsFixed[C]String` or `ns_auto_[c]string!` for dynamic stack allocated -//! strings which are expected to hold short string values. -//! -//! Use `*{const,mut} nsA[C]String` (`{const,} nsA[C]String*` in C++) for -//! function arguments passed across the rust/C++ language boundary. -//! -//! Use `ns[C]StringRepr` for string struct members which are shared between -//! rust and C++, but be careful, because this type lacks a `Drop` -//! implementation. -//! -//! # String Types -//! -//! ## `nsA[C]String` -//! -//! The core types in this module are `nsAString` and `nsACString`. These types -//! are zero-sized as far as rust is concerned, and are safe to pass around -//! behind both references (in rust code), and pointers (in C++ code). They -//! represent a handle to a XPCOM string which holds either `u16` or `u8` -//! characters respectively. The backing character buffer is guaranteed to live -//! as long as the reference to the `nsAString` or `nsACString`. -//! -//! These types in rust are simply used as dummy types. References to them -//! represent a pointer to the beginning of a variable-sized `#[repr(C)]` struct -//! which is common between both C++ and Rust implementations. In C++, their -//! corresponding types are also named `nsAString` or `nsACString`, and they are -//! defined within the `nsTSubstring.{cpp,h}` file. -//! -//! ### Valid Operations -//! -//! An `&nsA[C]String` acts like rust's `&str`, in that it is a borrowed -//! reference to the backing data. When used as an argument to other functions -//! on `&mut nsA[C]String`, optimizations can be performed to avoid copying -//! buffers, as information about the backing storage is preserved. -//! -//! An `&mut nsA[C]String` acts like rust's `&mut Cow<str>`, in that it is a -//! mutable reference to a potentially borrowed string, which when modified will -//! ensure that it owns its own backing storage. This type can be appended to -//! with the methods `.append`, `.append_utf{8,16}`, and with the `write!` -//! macro, and can be assigned to with `.assign`. -//! -//! ## `ns[C]String<'a>` -//! -//! This type is an maybe-owned string type. It acts similarially to a -//! `Cow<[{u8,u16}]>`. This type provides `Deref` and `DerefMut` implementations -//! to `nsA[C]String`, which provides the methods for manipulating this type. -//! This type's lifetime parameter, `'a`, represents the lifetime of the backing -//! storage. When modified this type may re-allocate in order to ensure that it -//! does not mutate its backing storage. -//! -//! `ns[C]String`s can be constructed either with `ns[C]String::new()`, which -//! creates an empty `ns[C]String<'static>`, or through one of the provided -//! `From` implementations. Both string types may be constructed `From<&'a -//! str>`, with `nsCString` having a `'a` lifetime, as the storage is shared -//! with the `str`, while `nsString` has a `'static` lifetime, as its storage -//! has to be transcoded. -//! -//! When passing this type by reference, prefer passing a `&nsA[C]String` or -//! `&mut nsA[C]String`. to passing this type. -//! -//! This type is _not_ `#[repr(C)]`, as it has a `Drop` impl, which in versions -//! of `rustc < 1.13` adds drop flags to the struct, which messes up the layout, -//! making it unsafe to pass across the FFI boundary. The rust compiler will -//! warn if this type appears in `extern "C"` function definitions. -//! -//! When passing this type across the language boundary, pass it as `*const -//! nsA[C]String` for an immutable reference, or `*mut nsA[C]String` for a -//! mutable reference. -//! -//! This type is similar to the C++ type of the same name. -//! -//! ## `nsFixed[C]String<'a>` -//! -//! This type is a string type with fixed backing storage. It is created with -//! `nsFixed[C]String::new(buffer)`, passing a mutable reference to a buffer as -//! the argument. This buffer will be used as backing storage whenever the -//! resulting string will fit within it, falling back to heap allocations only -//! when the string size exceeds that of the backing buffer. -//! -//! Like `ns[C]String`, this type dereferences to `nsA[C]String` which provides -//! the methods for manipulating the type, and is not `#[repr(C)]`. -//! -//! When passing this type by reference, prefer passing a `&nsA[C]String` or -//! `&mut nsA[C]String`. to passing this type. -//! -//! This type is _not_ `#[repr(C)]`, as it has a `Drop` impl, which in versions -//! of `rustc < 1.13` adds drop flags to the struct, which messes up the layout, -//! making it unsafe to pass across the FFI boundary. The rust compiler will -//! warn if this type appears in `extern "C"` function definitions. -//! -//! When passing this type across the language boundary, pass it as `*const -//! nsA[C]String` for an immutable reference, or `*mut nsA[C]String` for a -//! mutable reference. -//! -//! This type is similar to the C++ type of the same name. -//! -//! ## `ns_auto_[c]string!($name)` -//! -//! This is a helper macro which defines a fixed size, (currently 64 character), -//! backing array on the stack, and defines a local variable with name `$name` -//! which is a `nsFixed[C]String` using this buffer as its backing storage. -//! -//! Usage of this macro is similar to the C++ type `nsAuto[C]String`, but could -//! not be implemented as a basic type due to the differences between rust and -//! C++'s move semantics. -//! -//! ## `ns[C]StringRepr` -//! -//! This type represents a C++ `ns[C]String`. This type is `#[repr(C)]` and is -//! safe to use in struct definitions which are shared across the language -//! boundary. It automatically dereferences to `&{mut,} nsA[C]String`, and thus -//! can be treated similarially to `ns[C]String`. -//! -//! If this type is dropped in rust, it will not free its backing storage. This -//! is because types implementing `Drop` have a drop flag added, which messes up -//! the layout of this type. When drop flags are removed, which should happen in -//! `rustc 1.13` (see rust-lang/rust#35764), this type will likely be removed, -//! and replaced with direct usage of `ns[C]String<'a>`, as its layout may be -//! identical. This module provides rust bindings to our xpcom ns[C]String -//! types. - -#![allow(non_camel_case_types)] - -use std::ops::{Deref, DerefMut}; -use std::marker::PhantomData; -use std::slice; -use std::ptr; -use std::mem; -use std::fmt; -use std::cmp; -use std::str; -use std::u32; - -////////////////////////////////// -// Internal Implemenation Flags // -////////////////////////////////// - -const F_NONE: u32 = 0; // no flags - -// data flags are in the lower 16-bits -const F_TERMINATED: u32 = 1 << 0; // IsTerminated returns true -const F_VOIDED: u32 = 1 << 1; // IsVoid returns true -const F_SHARED: u32 = 1 << 2; // mData points to a heap-allocated, shared buffer -const F_OWNED: u32 = 1 << 3; // mData points to a heap-allocated, raw buffer -const F_FIXED: u32 = 1 << 4; // mData points to a fixed-size writable, dependent buffer -const F_LITERAL: u32 = 1 << 5; // mData points to a string literal; F_TERMINATED will also be set - -// class flags are in the upper 16-bits -const F_CLASS_FIXED: u32 = 1 << 16; // indicates that |this| is of type nsTFixedString - -//////////////////////////////////// -// Generic String Bindings Macros // -//////////////////////////////////// - -macro_rules! define_string_types { - { - char_t = $char_t: ty; - AString = $AString: ident; - String = $String: ident; - FixedString = $FixedString: ident; - - StringRepr = $StringRepr: ident; - FixedStringRepr = $FixedStringRepr: ident; - AutoStringRepr = $AutoStringRepr: ident; - } => { - /// The representation of a ns[C]String type in C++. This type is - /// used internally by our definition of ns[C]String to ensure layout - /// compatibility with the C++ ns[C]String type. - /// - /// This type may also be used in place of a C++ ns[C]String inside of - /// struct definitions which are shared with C++, as it has identical - /// layout to our ns[C]String type. Due to drop flags, our ns[C]String - /// type does not have identical layout. When drop flags are removed, - /// this type will likely be made a private implementation detail, and - /// its uses will be replaced with `ns[C]String`. - /// - /// This struct will leak its data if dropped from rust. See the module - /// documentation for more information on this type. - #[repr(C)] - pub struct $StringRepr { - data: *const $char_t, - length: u32, - flags: u32, - } - - impl Deref for $StringRepr { - type Target = $AString; - fn deref(&self) -> &$AString { - unsafe { - mem::transmute(self) - } - } - } - - impl DerefMut for $StringRepr { - fn deref_mut(&mut self) -> &mut $AString { - unsafe { - mem::transmute(self) - } - } - } - - /// The representation of a nsFixed[C]String type in C++. This type is - /// used internally by our definition of nsFixed[C]String to ensure layout - /// compatibility with the C++ nsFixed[C]String type. - #[repr(C)] - struct $FixedStringRepr { - base: $StringRepr, - capacity: u32, - buffer: *mut $char_t, - } - - /// This type is the abstract type which is used for interacting with - /// strings in rust. Each string type can derefence to an instance of - /// this type, which provides the useful operations on strings. - /// - /// NOTE: Rust thinks this type has a size of 0, because the data - /// associated with it is not necessarially safe to move. It is not safe - /// to construct a nsAString yourself, unless it is received by - /// dereferencing one of these types. - /// - /// NOTE: The `[u8; 0]` member is zero sized, and only exists to prevent - /// the construction by code outside of this module. It is used instead - /// of a private `()` member because the `improper_ctypes` lint complains - /// about some ZST members in `extern "C"` function declarations. - #[repr(C)] - pub struct $AString { - _prohibit_constructor: [u8; 0], - } - - impl Deref for $AString { - type Target = [$char_t]; - fn deref(&self) -> &[$char_t] { - unsafe { - // This is legal, as all $AString values actually point to a - // $StringRepr - let this: &$StringRepr = mem::transmute(self); - if this.data.is_null() { - debug_assert!(this.length == 0); - // Use an arbitrary non-null value as the pointer - slice::from_raw_parts(0x1 as *const $char_t, 0) - } else { - slice::from_raw_parts(this.data, this.length as usize) - } - } - } - } - - impl cmp::PartialEq for $AString { - fn eq(&self, other: &$AString) -> bool { - &self[..] == &other[..] - } - } - - impl cmp::PartialEq<[$char_t]> for $AString { - fn eq(&self, other: &[$char_t]) -> bool { - &self[..] == other - } - } - - impl<'a> cmp::PartialEq<$String<'a>> for $AString { - fn eq(&self, other: &$String<'a>) -> bool { - self.eq(&**other) - } - } - - impl<'a> cmp::PartialEq<$FixedString<'a>> for $AString { - fn eq(&self, other: &$FixedString<'a>) -> bool { - self.eq(&**other) - } - } - - pub struct $String<'a> { - hdr: $StringRepr, - _marker: PhantomData<&'a [$char_t]>, - } - - impl $String<'static> { - pub fn new() -> $String<'static> { - $String { - hdr: $StringRepr { - data: ptr::null(), - length: 0, - flags: F_NONE, - }, - _marker: PhantomData, - } - } - } - - impl<'a> Deref for $String<'a> { - type Target = $AString; - fn deref(&self) -> &$AString { - &self.hdr - } - } - - impl<'a> DerefMut for $String<'a> { - fn deref_mut(&mut self) -> &mut $AString { - &mut self.hdr - } - } - - impl<'a> From<&'a String> for $String<'a> { - fn from(s: &'a String) -> $String<'a> { - $String::from(&s[..]) - } - } - - impl<'a> From<&'a Vec<$char_t>> for $String<'a> { - fn from(s: &'a Vec<$char_t>) -> $String<'a> { - $String::from(&s[..]) - } - } - - impl<'a> From<&'a [$char_t]> for $String<'a> { - fn from(s: &'a [$char_t]) -> $String<'a> { - assert!(s.len() < (u32::MAX as usize)); - $String { - hdr: $StringRepr { - data: s.as_ptr(), - length: s.len() as u32, - flags: F_NONE, - }, - _marker: PhantomData, - } - } - } - - impl From<Box<[$char_t]>> for $String<'static> { - fn from(s: Box<[$char_t]>) -> $String<'static> { - assert!(s.len() < (u32::MAX as usize)); - // SAFETY NOTE: This method produces an F_OWNED ns[C]String from - // a Box<[$char_t]>. this is only safe because in the Gecko - // tree, we use the same allocator for Rust code as for C++ - // code, meaning that our box can be legally freed with - // libc::free(). - let length = s.len() as u32; - let ptr = s.as_ptr(); - mem::forget(s); - $String { - hdr: $StringRepr { - data: ptr, - length: length, - flags: F_OWNED, - }, - _marker: PhantomData, - } - } - } - - impl From<Vec<$char_t>> for $String<'static> { - fn from(s: Vec<$char_t>) -> $String<'static> { - s.into_boxed_slice().into() - } - } - - impl<'a> From<&'a $AString> for $String<'static> { - fn from(s: &'a $AString) -> $String<'static> { - let mut string = $String::new(); - string.assign(s); - string - } - } - - impl<'a> fmt::Write for $String<'a> { - fn write_str(&mut self, s: &str) -> Result<(), fmt::Error> { - $AString::write_str(self, s) - } - } - - impl<'a> fmt::Display for $String<'a> { - fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> { - <$AString as fmt::Display>::fmt(self, f) - } - } - - impl<'a> fmt::Debug for $String<'a> { - fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> { - <$AString as fmt::Debug>::fmt(self, f) - } - } - - impl<'a> cmp::PartialEq for $String<'a> { - fn eq(&self, other: &$String<'a>) -> bool { - $AString::eq(self, other) - } - } - - impl<'a> cmp::PartialEq<[$char_t]> for $String<'a> { - fn eq(&self, other: &[$char_t]) -> bool { - $AString::eq(self, other) - } - } - - impl<'a, 'b> cmp::PartialEq<&'b [$char_t]> for $String<'a> { - fn eq(&self, other: &&'b [$char_t]) -> bool { - $AString::eq(self, *other) - } - } - - impl<'a> cmp::PartialEq<str> for $String<'a> { - fn eq(&self, other: &str) -> bool { - $AString::eq(self, other) - } - } - - impl<'a, 'b> cmp::PartialEq<&'b str> for $String<'a> { - fn eq(&self, other: &&'b str) -> bool { - $AString::eq(self, *other) - } - } - - impl<'a> Drop for $String<'a> { - fn drop(&mut self) { - unsafe { - self.finalize(); - } - } - } - - /// A nsFixed[C]String is a string which uses a fixed size mutable - /// backing buffer for storing strings which will fit within that - /// buffer, rather than using heap allocations. - pub struct $FixedString<'a> { - hdr: $FixedStringRepr, - _marker: PhantomData<&'a mut [$char_t]>, - } - - impl<'a> $FixedString<'a> { - pub fn new(buf: &'a mut [$char_t]) -> $FixedString<'a> { - let len = buf.len(); - assert!(len < (u32::MAX as usize)); - let buf_ptr = buf.as_mut_ptr(); - $FixedString { - hdr: $FixedStringRepr { - base: $StringRepr { - data: ptr::null(), - length: 0, - flags: F_CLASS_FIXED, - }, - capacity: len as u32, - buffer: buf_ptr, - }, - _marker: PhantomData, - } - } - } - - impl<'a> Deref for $FixedString<'a> { - type Target = $AString; - fn deref(&self) -> &$AString { - &self.hdr.base - } - } - - impl<'a> DerefMut for $FixedString<'a> { - fn deref_mut(&mut self) -> &mut $AString { - &mut self.hdr.base - } - } - - impl<'a> fmt::Write for $FixedString<'a> { - fn write_str(&mut self, s: &str) -> Result<(), fmt::Error> { - $AString::write_str(self, s) - } - } - - impl<'a> fmt::Display for $FixedString<'a> { - fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> { - <$AString as fmt::Display>::fmt(self, f) - } - } - - impl<'a> fmt::Debug for $FixedString<'a> { - fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> { - <$AString as fmt::Debug>::fmt(self, f) - } - } - - impl<'a> cmp::PartialEq for $FixedString<'a> { - fn eq(&self, other: &$FixedString<'a>) -> bool { - $AString::eq(self, other) - } - } - - impl<'a> cmp::PartialEq<[$char_t]> for $FixedString<'a> { - fn eq(&self, other: &[$char_t]) -> bool { - $AString::eq(self, other) - } - } - - impl<'a, 'b> cmp::PartialEq<&'b [$char_t]> for $FixedString<'a> { - fn eq(&self, other: &&'b [$char_t]) -> bool { - $AString::eq(self, *other) - } - } - - impl<'a> cmp::PartialEq<str> for $FixedString<'a> { - fn eq(&self, other: &str) -> bool { - $AString::eq(self, other) - } - } - - impl<'a, 'b> cmp::PartialEq<&'b str> for $FixedString<'a> { - fn eq(&self, other: &&'b str) -> bool { - $AString::eq(self, *other) - } - } - - impl<'a> Drop for $FixedString<'a> { - fn drop(&mut self) { - unsafe { - self.finalize(); - } - } - } - } -} - -/////////////////////////////////////////// -// Bindings for nsCString (u8 char type) // -/////////////////////////////////////////// - -define_string_types! { - char_t = u8; - - AString = nsACString; - String = nsCString; - FixedString = nsFixedCString; - - StringRepr = nsCStringRepr; - FixedStringRepr = nsFixedCStringRepr; - AutoStringRepr = nsAutoCStringRepr; -} - -impl nsACString { - /// Leaves the nsACString in an unstable state with a dangling data pointer. - /// Should only be used in drop implementations of rust types which wrap - /// this type. - unsafe fn finalize(&mut self) { - Gecko_FinalizeCString(self); - } - - pub fn assign(&mut self, other: &nsACString) { - unsafe { - Gecko_AssignCString(self as *mut _, other as *const _); - } - } - - pub fn assign_utf16(&mut self, other: &nsAString) { - self.assign(&nsCString::new()); - self.append_utf16(other); - } - - pub fn append(&mut self, other: &nsACString) { - unsafe { - Gecko_AppendCString(self as *mut _, other as *const _); - } - } - - pub fn append_utf16(&mut self, other: &nsAString) { - unsafe { - Gecko_AppendUTF16toCString(self as *mut _, other as *const _); - } - } - - pub unsafe fn as_str_unchecked(&self) -> &str { - str::from_utf8_unchecked(self) - } -} - -impl<'a> From<&'a str> for nsCString<'a> { - fn from(s: &'a str) -> nsCString<'a> { - s.as_bytes().into() - } -} - -impl From<Box<str>> for nsCString<'static> { - fn from(s: Box<str>) -> nsCString<'static> { - s.into_string().into() - } -} - -impl From<String> for nsCString<'static> { - fn from(s: String) -> nsCString<'static> { - s.into_bytes().into() - } -} - -// Support for the write!() macro for appending to nsACStrings -impl fmt::Write for nsACString { - fn write_str(&mut self, s: &str) -> Result<(), fmt::Error> { - self.append(&nsCString::from(s)); - Ok(()) - } -} - -impl fmt::Display for nsACString { - fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> { - fmt::Display::fmt(&String::from_utf8_lossy(&self[..]), f) - } -} - -impl fmt::Debug for nsACString { - fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> { - fmt::Debug::fmt(&String::from_utf8_lossy(&self[..]), f) - } -} - -impl cmp::PartialEq<str> for nsACString { - fn eq(&self, other: &str) -> bool { - &self[..] == other.as_bytes() - } -} - -#[macro_export] -macro_rules! ns_auto_cstring { - ($name:ident) => { - let mut buf: [u8; 64] = [0; 64]; - let mut $name = $crate::nsFixedCString::new(&mut buf); - } -} - -/////////////////////////////////////////// -// Bindings for nsString (u16 char type) // -/////////////////////////////////////////// - -define_string_types! { - char_t = u16; - - AString = nsAString; - String = nsString; - FixedString = nsFixedString; - - StringRepr = nsStringRepr; - FixedStringRepr = nsFixedStringRepr; - AutoStringRepr = nsAutoStringRepr; -} - -impl nsAString { - /// Leaves the nsAString in an unstable state with a dangling data pointer. - /// Should only be used in drop implementations of rust types which wrap - /// this type. - unsafe fn finalize(&mut self) { - Gecko_FinalizeString(self); - } - - pub fn assign(&mut self, other: &nsAString) { - unsafe { - Gecko_AssignString(self as *mut _, other as *const _); - } - } - - pub fn assign_utf8(&mut self, other: &nsACString) { - self.assign(&nsString::new()); - self.append_utf8(other); - } - - pub fn append(&mut self, other: &nsAString) { - unsafe { - Gecko_AppendString(self as *mut _, other as *const _); - } - } - - pub fn append_utf8(&mut self, other: &nsACString) { - unsafe { - Gecko_AppendUTF8toString(self as *mut _, other as *const _); - } - } -} - -// NOTE: The From impl for a string slice for nsString produces a <'static> -// lifetime, as it allocates. -impl<'a> From<&'a str> for nsString<'static> { - fn from(s: &'a str) -> nsString<'static> { - s.encode_utf16().collect::<Vec<u16>>().into() - } -} - -// Support for the write!() macro for writing to nsStrings -impl fmt::Write for nsAString { - fn write_str(&mut self, s: &str) -> Result<(), fmt::Error> { - // Directly invoke gecko's routines for appending utf8 strings to - // nsAString values, to avoid as much overhead as possible - self.append_utf8(&nsCString::from(s)); - Ok(()) - } -} - -impl fmt::Display for nsAString { - fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> { - fmt::Display::fmt(&String::from_utf16_lossy(&self[..]), f) - } -} - -impl fmt::Debug for nsAString { - fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> { - fmt::Debug::fmt(&String::from_utf16_lossy(&self[..]), f) - } -} - -impl cmp::PartialEq<str> for nsAString { - fn eq(&self, other: &str) -> bool { - other.encode_utf16().eq(self.iter().cloned()) - } -} - -#[macro_export] -macro_rules! ns_auto_string { - ($name:ident) => { - let mut buf: [u16; 64] = [0; 64]; - let mut $name = $crate::nsFixedString::new(&mut buf); - } -} - -// NOTE: These bindings currently only expose infallible operations. Perhaps -// consider allowing for fallible methods? -extern "C" { - // Gecko implementation in nsSubstring.cpp - fn Gecko_FinalizeCString(this: *mut nsACString); - fn Gecko_AssignCString(this: *mut nsACString, other: *const nsACString); - fn Gecko_AppendCString(this: *mut nsACString, other: *const nsACString); - - fn Gecko_FinalizeString(this: *mut nsAString); - fn Gecko_AssignString(this: *mut nsAString, other: *const nsAString); - fn Gecko_AppendString(this: *mut nsAString, other: *const nsAString); - - // Gecko implementation in nsReadableUtils.cpp - fn Gecko_AppendUTF16toCString(this: *mut nsACString, other: *const nsAString); - fn Gecko_AppendUTF8toString(this: *mut nsAString, other: *const nsACString); -} - -////////////////////////////////////// -// Repr Validation Helper Functions // -////////////////////////////////////// - -pub mod test_helpers { - //! This module only exists to help with ensuring that the layout of the - //! structs inside of rust and C++ are identical. - //! - //! It is public to ensure that these testing functions are avaliable to - //! gtest code. - - use super::{ - nsFixedCStringRepr, - nsFixedStringRepr, - nsCStringRepr, - nsStringRepr, - F_NONE, - F_TERMINATED, - F_VOIDED, - F_SHARED, - F_OWNED, - F_FIXED, - F_LITERAL, - F_CLASS_FIXED, - }; - use std::mem; - - /// Generates an #[no_mangle] extern "C" function which returns the size and - /// alignment of the given type with the given name. - macro_rules! size_align_check { - ($T:ty, $fname:ident) => { - #[no_mangle] - #[allow(non_snake_case)] - pub extern fn $fname(size: *mut usize, align: *mut usize) { - unsafe { - *size = mem::size_of::<$T>(); - *align = mem::align_of::<$T>(); - } - } - } - } - - size_align_check!(nsStringRepr, Rust_Test_ReprSizeAlign_nsString); - size_align_check!(nsCStringRepr, Rust_Test_ReprSizeAlign_nsCString); - size_align_check!(nsFixedStringRepr, Rust_Test_ReprSizeAlign_nsFixedString); - size_align_check!(nsFixedCStringRepr, Rust_Test_ReprSizeAlign_nsFixedCString); - - /// Generates a $[no_mangle] extern "C" function which returns the size, - /// alignment and offset in the parent struct of a given member, with the - /// given name. - /// - /// This method can trigger Undefined Behavior if the accessing the member - /// $member on a given type would use that type's `Deref` implementation. - macro_rules! member_check { - ($T:ty, $member:ident, $method:ident) => { - #[no_mangle] - #[allow(non_snake_case)] - pub extern fn $method(size: *mut usize, - align: *mut usize, - offset: *mut usize) { - unsafe { - // Create a temporary value of type T to get offsets, sizes - // and aligns off of - let tmp: $T = mem::zeroed(); - *size = mem::size_of_val(&tmp.$member); - *align = mem::align_of_val(&tmp.$member); - *offset = - (&tmp.$member as *const _ as usize) - - (&tmp as *const _ as usize); - mem::forget(tmp); - } - } - } - } - - member_check!(nsStringRepr, data, Rust_Test_Member_nsString_mData); - member_check!(nsStringRepr, length, Rust_Test_Member_nsString_mLength); - member_check!(nsStringRepr, flags, Rust_Test_Member_nsString_mFlags); - member_check!(nsCStringRepr, data, Rust_Test_Member_nsCString_mData); - member_check!(nsCStringRepr, length, Rust_Test_Member_nsCString_mLength); - member_check!(nsCStringRepr, flags, Rust_Test_Member_nsCString_mFlags); - member_check!(nsFixedStringRepr, capacity, Rust_Test_Member_nsFixedString_mFixedCapacity); - member_check!(nsFixedStringRepr, buffer, Rust_Test_Member_nsFixedString_mFixedBuf); - member_check!(nsFixedCStringRepr, capacity, Rust_Test_Member_nsFixedCString_mFixedCapacity); - member_check!(nsFixedCStringRepr, buffer, Rust_Test_Member_nsFixedCString_mFixedBuf); - - #[no_mangle] - #[allow(non_snake_case)] - pub extern fn Rust_Test_NsStringFlags(f_none: *mut u32, - f_terminated: *mut u32, - f_voided: *mut u32, - f_shared: *mut u32, - f_owned: *mut u32, - f_fixed: *mut u32, - f_literal: *mut u32, - f_class_fixed: *mut u32) { - unsafe { - *f_none = F_NONE; - *f_terminated = F_TERMINATED; - *f_voided = F_VOIDED; - *f_shared = F_SHARED; - *f_owned = F_OWNED; - *f_fixed = F_FIXED; - *f_literal = F_LITERAL; - *f_class_fixed = F_CLASS_FIXED; - } - } -} |