Remove cargo nsstring component

Part 3 for #58

13 files changed, 0 insertions, 1150 deletions

diff --git a/toolkit/library/gtest/rust/Cargo.lock b/toolkit/library/gtest/rust/Cargo.lock
index 4f0318ab41..21b54ca305 100644
--- a/toolkit/library/gtest/rust/Cargo.lock
+++ b/toolkit/library/gtest/rust/Cargo.lock
@@ -39,17 +39,6 @@ version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
-name = "nsstring"
-version = "0.1.0"
-
-[[package]]
-name = "nsstring-gtest"
-version = "0.1.0"
-dependencies = [
- "nsstring 0.1.0",
-]
-
-[[package]]
 name = "unicode-bidi"
 version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
diff --git a/toolkit/library/gtest/rust/Cargo.toml b/toolkit/library/gtest/rust/Cargo.toml
index 38ca72d2c8..f1a52aa4f3 100644
--- a/toolkit/library/gtest/rust/Cargo.toml
+++ b/toolkit/library/gtest/rust/Cargo.toml
@@ -6,7 +6,6 @@ license = "MPL-2.0"
 description = "Testing code for libgkrust"
 
 [dependencies]
-nsstring-gtest = { path = "../../../../xpcom/rust/nsstring/gtest" }
 gkrust-shared = { path = "../../rust/shared" }
 
 [lib]
diff --git a/toolkit/library/gtest/rust/lib.rs b/toolkit/library/gtest/rust/lib.rs
index eb0f102b99..69dd0b9e64 100644
--- a/toolkit/library/gtest/rust/lib.rs
+++ b/toolkit/library/gtest/rust/lib.rs
@@ -3,4 +3,3 @@
 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 extern crate gkrust_shared;
-extern crate nsstring_gtest;
diff --git a/toolkit/library/rust/Cargo.lock b/toolkit/library/rust/Cargo.lock
index 5ab22840ac..ae9d84eed5 100644
--- a/toolkit/library/rust/Cargo.lock
+++ b/toolkit/library/rust/Cargo.lock
@@ -38,10 +38,6 @@ version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
-name = "nsstring"
-version = "0.1.0"
-
-[[package]]
 name = "unicode-bidi"
 version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
diff --git a/toolkit/library/rust/shared/Cargo.toml b/toolkit/library/rust/shared/Cargo.toml
index 4b94a1c94d..d4b57dd10b 100644
--- a/toolkit/library/rust/shared/Cargo.toml
+++ b/toolkit/library/rust/shared/Cargo.toml
@@ -5,9 +5,6 @@ authors = ["nobody@mozilla.org"]
 license = "MPL-2.0"
 description = "Shared Rust code for libxul"
 
-[dependencies]
-nsstring = { path = "../../../../xpcom/rust/nsstring" }
-
 [lib]
 path = "lib.rs"
 test = false
diff --git a/toolkit/library/rust/shared/lib.rs b/toolkit/library/rust/shared/lib.rs
index f6d7a5ae03..6fbb80a0bb 100644
--- a/toolkit/library/rust/shared/lib.rs
+++ b/toolkit/library/rust/shared/lib.rs
@@ -2,4 +2,3 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-extern crate nsstring;
diff --git a/xpcom/moz.build b/xpcom/moz.build
index 45a83c5c81..fe94edfce2 100644
--- a/xpcom/moz.build
+++ b/xpcom/moz.build
@@ -31,7 +31,6 @@ if CONFIG['OS_ARCH'] == 'WINNT' and CONFIG['MOZ_DEBUG']:
 
 TEST_DIRS += [
     'tests',
-    'rust/nsstring/gtest',
 ]
 
 #  Can't build internal xptcall tests that use symbols which are not exported.
diff --git a/xpcom/rust/nsstring/Cargo.toml b/xpcom/rust/nsstring/Cargo.toml
deleted file mode 100644
index d86a1ad264..0000000000
--- a/xpcom/rust/nsstring/Cargo.toml
+++ /dev/null
@@ -1,8 +0,0 @@
-[package]
-name = "nsstring"
-version = "0.1.0"
-authors = ["nobody@mozilla.com"]
-license = "MPL-2.0"
-description = "Rust bindings to xpcom string types"
-
-[dependencies]
diff --git a/xpcom/rust/nsstring/gtest/Cargo.toml b/xpcom/rust/nsstring/gtest/Cargo.toml
deleted file mode 100644
index 44897ec98f..0000000000
--- a/xpcom/rust/nsstring/gtest/Cargo.toml
+++ /dev/null
@@ -1,12 +0,0 @@
-[package]
-name = "nsstring-gtest"
-version = "0.1.0"
-authors = ["nobody@mozilla.com"]
-license = "MPL-2.0"
-description = "Tests for rust bindings to xpcom string types"
-
-[dependencies]
-nsstring = { path = "../" }
-
-[lib]
-path = "test.rs"
diff --git a/xpcom/rust/nsstring/gtest/Test.cpp b/xpcom/rust/nsstring/gtest/Test.cpp
deleted file mode 100644
index 93d2ee1d79..0000000000
--- a/xpcom/rust/nsstring/gtest/Test.cpp
+++ /dev/null
@@ -1,131 +0,0 @@
-#include "gtest/gtest.h"
-#include <stdint.h>
-#include "nsString.h"
-
-extern "C" {
-  // This function is called by the rust code in test.rs if a non-fatal test
-  // failure occurs.
-  void GTest_ExpectFailure(const char* aMessage) {
-    EXPECT_STREQ(aMessage, "");
-  }
-}
-
-#define SIZE_ALIGN_CHECK(Clazz)                                         \
-  extern "C" void Rust_Test_ReprSizeAlign_##Clazz(size_t* size, size_t* align); \
-  TEST(RustNsString, ReprSizeAlign_##Clazz) {                           \
-    size_t size, align;                                                 \
-    Rust_Test_ReprSizeAlign_##Clazz(&size, &align);                     \
-    EXPECT_EQ(size, sizeof(Clazz));                                     \
-    EXPECT_EQ(align, alignof(Clazz));                                   \
-  }
-
-SIZE_ALIGN_CHECK(nsString)
-SIZE_ALIGN_CHECK(nsCString)
-SIZE_ALIGN_CHECK(nsFixedString)
-SIZE_ALIGN_CHECK(nsFixedCString)
-
-#define MEMBER_CHECK(Clazz, Member)                                     \
-  extern "C" void Rust_Test_Member_##Clazz##_##Member(size_t* size,     \
-                                                      size_t* align,    \
-                                                      size_t* offset);  \
-  TEST(RustNsString, ReprMember_##Clazz##_##Member) {                   \
-    class Hack : public Clazz {                                         \
-    public:                                                             \
-      static void RunTest() {                                           \
-        size_t size, align, offset;                                     \
-        Rust_Test_Member_##Clazz##_##Member(&size, &align, &offset);    \
-        EXPECT_EQ(size, sizeof(mozilla::DeclVal<Hack>().Member));       \
-        EXPECT_EQ(size, alignof(decltype(mozilla::DeclVal<Hack>().Member))); \
-        EXPECT_EQ(offset, offsetof(Hack, Member));                      \
-      }                                                                 \
-    };                                                                  \
-    static_assert(sizeof(Clazz) == sizeof(Hack), "Hack matches class"); \
-    Hack::RunTest();                                                    \
-  }
-
-MEMBER_CHECK(nsString, mData)
-MEMBER_CHECK(nsString, mLength)
-MEMBER_CHECK(nsString, mFlags)
-MEMBER_CHECK(nsCString, mData)
-MEMBER_CHECK(nsCString, mLength)
-MEMBER_CHECK(nsCString, mFlags)
-MEMBER_CHECK(nsFixedString, mFixedCapacity)
-MEMBER_CHECK(nsFixedString, mFixedBuf)
-MEMBER_CHECK(nsFixedCString, mFixedCapacity)
-MEMBER_CHECK(nsFixedCString, mFixedBuf)
-
-extern "C" void Rust_Test_NsStringFlags(uint32_t* f_none,
-                                        uint32_t* f_terminated,
-                                        uint32_t* f_voided,
-                                        uint32_t* f_shared,
-                                        uint32_t* f_owned,
-                                        uint32_t* f_fixed,
-                                        uint32_t* f_literal,
-                                        uint32_t* f_class_fixed);
-TEST(RustNsString, NsStringFlags) {
-  uint32_t f_none, f_terminated, f_voided, f_shared, f_owned, f_fixed, f_literal, f_class_fixed;
-  Rust_Test_NsStringFlags(&f_none, &f_terminated,
-                          &f_voided, &f_shared,
-                          &f_owned, &f_fixed,
-                          &f_literal, &f_class_fixed);
-  EXPECT_EQ(f_none, nsAString::F_NONE);
-  EXPECT_EQ(f_none, nsACString::F_NONE);
-  EXPECT_EQ(f_terminated, nsAString::F_TERMINATED);
-  EXPECT_EQ(f_terminated, nsACString::F_TERMINATED);
-  EXPECT_EQ(f_voided, nsAString::F_VOIDED);
-  EXPECT_EQ(f_voided, nsACString::F_VOIDED);
-  EXPECT_EQ(f_shared, nsAString::F_SHARED);
-  EXPECT_EQ(f_shared, nsACString::F_SHARED);
-  EXPECT_EQ(f_owned, nsAString::F_OWNED);
-  EXPECT_EQ(f_owned, nsACString::F_OWNED);
-  EXPECT_EQ(f_fixed, nsAString::F_FIXED);
-  EXPECT_EQ(f_fixed, nsACString::F_FIXED);
-  EXPECT_EQ(f_literal, nsAString::F_LITERAL);
-  EXPECT_EQ(f_literal, nsACString::F_LITERAL);
-  EXPECT_EQ(f_class_fixed, nsAString::F_CLASS_FIXED);
-  EXPECT_EQ(f_class_fixed, nsACString::F_CLASS_FIXED);
-}
-
-extern "C" void Rust_StringFromCpp(const nsACString* aCStr, const nsAString* aStr);
-TEST(RustNsString, StringFromCpp) {
-  nsAutoCString foo;
-  foo.AssignASCII("Hello, World!");
-
-  nsAutoString bar;
-  bar.AssignASCII("Hello, World!");
-
-  Rust_StringFromCpp(&foo, &bar);
-}
-
-extern "C" void Rust_AssignFromRust(nsACString* aCStr, nsAString* aStr);
-TEST(RustNsString, AssignFromRust) {
-  nsAutoCString cs;
-  nsAutoString s;
-  Rust_AssignFromRust(&cs, &s);
-  EXPECT_TRUE(cs.EqualsASCII("Hello, World!"));
-  EXPECT_TRUE(s.EqualsASCII("Hello, World!"));
-}
-
-extern "C" {
-  void Cpp_AssignFromCpp(nsACString* aCStr, nsAString* aStr) {
-    aCStr->AssignASCII("Hello, World!");
-    aStr->AssignASCII("Hello, World!");
-  }
-}
-extern "C" void Rust_AssignFromCpp();
-TEST(RustNsString, AssignFromCpp) {
-  Rust_AssignFromCpp();
-}
-extern "C" void Rust_FixedAssignFromCpp();
-TEST(RustNsString, FixedAssignFromCpp) {
-  Rust_FixedAssignFromCpp();
-}
-extern "C" void Rust_AutoAssignFromCpp();
-TEST(RustNsString, AutoAssignFromCpp) {
-  Rust_AutoAssignFromCpp();
-}
-
-extern "C" void Rust_StringWrite();
-TEST(RustNsString, StringWrite) {
-  Rust_StringWrite();
-}
diff --git a/xpcom/rust/nsstring/gtest/moz.build b/xpcom/rust/nsstring/gtest/moz.build
deleted file mode 100644
index 5bed9e57e5..0000000000
--- a/xpcom/rust/nsstring/gtest/moz.build
+++ /dev/null
@@ -1,12 +0,0 @@
-# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
-# vim: set filetype=python:
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-if CONFIG['MOZ_RUST']:
-    UNIFIED_SOURCES += [
-        'Test.cpp'
-    ]
-
-FINAL_LIBRARY = 'xul-gtest'
diff --git a/xpcom/rust/nsstring/gtest/test.rs b/xpcom/rust/nsstring/gtest/test.rs
deleted file mode 100644
index 2968a1be79..0000000000
--- a/xpcom/rust/nsstring/gtest/test.rs
+++ /dev/null
@@ -1,112 +0,0 @@
-#![allow(non_snake_case)]
-
-#[macro_use]
-extern crate nsstring;
-
-use std::fmt::Write;
-use std::ffi::CString;
-use std::os::raw::c_char;
-use nsstring::*;
-
-fn nonfatal_fail(msg: String) {
-    extern "C" {
-        fn GTest_ExpectFailure(message: *const c_char);
-    }
-    unsafe {
-        GTest_ExpectFailure(CString::new(msg).unwrap().as_ptr());
-    }
-}
-
-/// This macro checks if the two arguments are equal, and causes a non-fatal
-/// GTest test failure if they are not.
-macro_rules! expect_eq {
-    ($x:expr, $y:expr) => {
-        match (&$x, &$y) {
-            (x, y) => if *x != *y {
-                nonfatal_fail(format!("check failed: (`{:?}` == `{:?}`) at {}:{}",
-                                      x, y, file!(), line!()))
-            }
-        }
-    }
-}
-
-#[no_mangle]
-pub extern fn Rust_StringFromCpp(cs: *const nsACString, s: *const nsAString) {
-    unsafe {
-        expect_eq!(&*cs, "Hello, World!");
-        expect_eq!(&*s, "Hello, World!");
-    }
-}
-
-#[no_mangle]
-pub extern fn Rust_AssignFromRust(cs: *mut nsACString, s: *mut nsAString) {
-    unsafe {
-        (*cs).assign(&nsCString::from("Hello, World!"));
-        expect_eq!(&*cs, "Hello, World!");
-        (*s).assign(&nsString::from("Hello, World!"));
-        expect_eq!(&*s, "Hello, World!");
-    }
-}
-
-extern "C" {
-    fn Cpp_AssignFromCpp(cs: *mut nsACString, s: *mut nsAString);
-}
-
-#[no_mangle]
-pub extern fn Rust_AssignFromCpp() {
-    let mut cs = nsCString::new();
-    let mut s = nsString::new();
-    unsafe {
-        Cpp_AssignFromCpp(&mut *cs, &mut *s);
-    }
-    expect_eq!(cs, "Hello, World!");
-    expect_eq!(s, "Hello, World!");
-}
-
-#[no_mangle]
-pub extern fn Rust_FixedAssignFromCpp() {
-    let mut cs_buf: [u8; 64] = [0; 64];
-    let cs_buf_ptr = &cs_buf as *const _ as usize;
-    let mut s_buf: [u16; 64] = [0; 64];
-    let s_buf_ptr = &s_buf as *const _ as usize;
-    let mut cs = nsFixedCString::new(&mut cs_buf);
-    let mut s = nsFixedString::new(&mut s_buf);
-    unsafe {
-        Cpp_AssignFromCpp(&mut *cs, &mut *s);
-    }
-    expect_eq!(cs, "Hello, World!");
-    expect_eq!(s, "Hello, World!");
-    expect_eq!(cs.as_ptr() as usize, cs_buf_ptr);
-    expect_eq!(s.as_ptr() as usize, s_buf_ptr);
-}
-
-#[no_mangle]
-pub extern fn Rust_AutoAssignFromCpp() {
-    ns_auto_cstring!(cs);
-    ns_auto_string!(s);
-    unsafe {
-        Cpp_AssignFromCpp(&mut *cs, &mut *s);
-    }
-    expect_eq!(cs, "Hello, World!");
-    expect_eq!(s, "Hello, World!");
-}
-
-#[no_mangle]
-pub extern fn Rust_StringWrite() {
-    ns_auto_cstring!(cs);
-    ns_auto_string!(s);
-
-    write!(s, "a").unwrap();
-    write!(cs, "a").unwrap();
-    expect_eq!(s, "a");
-    expect_eq!(cs, "a");
-    write!(s, "bc").unwrap();
-    write!(cs, "bc").unwrap();
-    expect_eq!(s, "abc");
-    expect_eq!(cs, "abc");
-    write!(s, "{}", 123).unwrap();
-    write!(cs, "{}", 123).unwrap();
-    expect_eq!(s, "abc123");
-    expect_eq!(cs, "abc123");
-}
-
diff --git a/xpcom/rust/nsstring/src/lib.rs b/xpcom/rust/nsstring/src/lib.rs
deleted file mode 100644
index cd518f3c5c..0000000000
--- 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;
-        }
-    }
-}