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/* 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
#![allow(unsafe_code)]
// This is needed for the constants in atom_macro.rs, because we have some
// atoms whose names differ only by case, e.g. datetime and dateTime.
#![allow(non_upper_case_globals)]
//! A drop-in replacement for string_cache, but backed by Gecko `nsAtom`s.
use crate::gecko_bindings::bindings::Gecko_AddRefAtom;
use crate::gecko_bindings::bindings::Gecko_Atomize;
use crate::gecko_bindings::bindings::Gecko_Atomize16;
use crate::gecko_bindings::bindings::Gecko_ReleaseAtom;
use crate::gecko_bindings::structs::root::mozilla::detail::gGkAtoms;
use crate::gecko_bindings::structs::root::mozilla::detail::GkAtoms_Atoms_AtomsCount;
use crate::gecko_bindings::structs::{nsAtom, nsDynamicAtom, nsStaticAtom};
use nsstring::{nsAString, nsStr};
use precomputed_hash::PrecomputedHash;
use std::borrow::{Borrow, Cow};
use std::char::{self, DecodeUtf16};
use std::fmt::{self, Write};
use std::hash::{Hash, Hasher};
use std::iter::Cloned;
use std::mem::{self, ManuallyDrop};
use std::num::NonZeroUsize;
use std::ops::Deref;
use std::{slice, str};
use style_traits::SpecifiedValueInfo;
use to_shmem::{SharedMemoryBuilder, ToShmem};
#[macro_use]
#[allow(improper_ctypes, non_camel_case_types, missing_docs)]
pub mod atom_macro {
include!(concat!(env!("OUT_DIR"), "/gecko/atom_macro.rs"));
}
#[macro_use]
pub mod namespace;
pub use self::namespace::{Namespace, WeakNamespace};
/// A handle to a Gecko atom. This is a type that can represent either:
///
/// * A strong reference to a dynamic atom (an `nsAtom` pointer), in which case
/// the `usize` just holds the pointer value.
///
/// * An index from `gGkAtoms` to the `nsStaticAtom` object (shifted to the left one bit, and with
/// the lower bit set to `1` to differentiate it from the above), so `(index << 1 | 1)`.
///
#[derive(Eq, PartialEq)]
#[repr(C)]
pub struct Atom(NonZeroUsize);
/// An atom *without* a strong reference.
///
/// Only usable as `&'a WeakAtom`,
/// where `'a` is the lifetime of something that holds a strong reference to that atom.
pub struct WeakAtom(nsAtom);
/// The number of static atoms we have.
const STATIC_ATOM_COUNT: usize = GkAtoms_Atoms_AtomsCount as usize;
impl Deref for Atom {
type Target = WeakAtom;
#[inline]
fn deref(&self) -> &WeakAtom {
unsafe {
let addr = if self.is_static() {
// This is really hot.
&gGkAtoms.mAtoms.get_unchecked(self.0.get() >> 1)._base as *const nsAtom
} else {
self.0.get() as *const nsAtom
};
WeakAtom::new(addr as *const nsAtom)
}
}
}
impl PrecomputedHash for Atom {
#[inline]
fn precomputed_hash(&self) -> u32 {
self.get_hash()
}
}
impl Borrow<WeakAtom> for Atom {
#[inline]
fn borrow(&self) -> &WeakAtom {
self
}
}
impl ToShmem for Atom {
fn to_shmem(&self, _builder: &mut SharedMemoryBuilder) -> to_shmem::Result<Self> {
if !self.is_static() {
return Err(format!(
"ToShmem failed for Atom: must be a static atom: {}",
self
));
}
Ok(ManuallyDrop::new(Atom(self.0)))
}
}
impl Eq for WeakAtom {}
impl PartialEq for WeakAtom {
#[inline]
fn eq(&self, other: &Self) -> bool {
let weak: *const WeakAtom = self;
let other: *const WeakAtom = other;
weak == other
}
}
impl PartialEq<Atom> for WeakAtom {
#[inline]
fn eq(&self, other: &Atom) -> bool {
self == &**other
}
}
unsafe impl Send for Atom {}
unsafe impl Sync for Atom {}
unsafe impl Sync for WeakAtom {}
impl WeakAtom {
/// Construct a `WeakAtom` from a raw `nsAtom`.
#[inline]
pub unsafe fn new<'a>(atom: *const nsAtom) -> &'a mut Self {
&mut *(atom as *mut WeakAtom)
}
/// Clone this atom, bumping the refcount if the atom is not static.
#[inline]
pub fn clone(&self) -> Atom {
unsafe { Atom::from_raw(self.as_ptr()) }
}
/// Get the atom hash.
#[inline]
pub fn get_hash(&self) -> u32 {
self.0.mHash
}
/// Get the atom as a slice of utf-16 chars.
#[inline]
pub fn as_slice(&self) -> &[u16] {
let string = if self.is_static() {
let atom_ptr = self.as_ptr() as *const nsStaticAtom;
let string_offset = unsafe { (*atom_ptr).mStringOffset };
let string_offset = -(string_offset as isize);
let u8_ptr = atom_ptr as *const u8;
// It is safe to use offset() here because both addresses are within
// the same struct, e.g. mozilla::detail::gGkAtoms.
unsafe { u8_ptr.offset(string_offset) as *const u16 }
} else {
let atom_ptr = self.as_ptr() as *const nsDynamicAtom;
let buffer_ptr = unsafe { (*atom_ptr).mStringBuffer.mRawPtr };
// Dynamic atom chars are stored at the end of the string buffer.
unsafe { buffer_ptr.offset(1) as *const u16 }
};
unsafe { slice::from_raw_parts(string, self.len() as usize) }
}
// NOTE: don't expose this, since it's slow, and easy to be misused.
fn chars(&self) -> DecodeUtf16<Cloned<slice::Iter<u16>>> {
char::decode_utf16(self.as_slice().iter().cloned())
}
/// Execute `cb` with the string that this atom represents.
///
/// Find alternatives to this function when possible, please, since it's
/// pretty slow.
pub fn with_str<F, Output>(&self, cb: F) -> Output
where
F: FnOnce(&str) -> Output,
{
let mut buffer = mem::MaybeUninit::<[u8; 64]>::uninit();
let buffer = unsafe { &mut *buffer.as_mut_ptr() };
// The total string length in utf16 is going to be less than or equal
// the slice length (each utf16 character is going to take at least one
// and at most 2 items in the utf16 slice).
//
// Each of those characters will take at most four bytes in the utf8
// one. Thus if the slice is less than 64 / 4 (16) we can guarantee that
// we'll decode it in place.
let owned_string;
let len = self.len();
let utf8_slice = if len <= 16 {
let mut total_len = 0;
for c in self.chars() {
let c = c.unwrap_or(char::REPLACEMENT_CHARACTER);
let utf8_len = c.encode_utf8(&mut buffer[total_len..]).len();
total_len += utf8_len;
}
let slice = unsafe { str::from_utf8_unchecked(&buffer[..total_len]) };
debug_assert_eq!(slice, String::from_utf16_lossy(self.as_slice()));
slice
} else {
owned_string = String::from_utf16_lossy(self.as_slice());
&*owned_string
};
cb(utf8_slice)
}
/// Returns whether this atom is static.
#[inline]
pub fn is_static(&self) -> bool {
self.0.mIsStatic() != 0
}
/// Returns whether this atom is ascii lowercase.
#[inline]
fn is_ascii_lowercase(&self) -> bool {
self.0.mIsAsciiLowercase() != 0
}
/// Returns the length of the atom string.
#[inline]
pub fn len(&self) -> u32 {
self.0.mLength()
}
/// Returns whether this atom is the empty string.
#[inline]
pub fn is_empty(&self) -> bool {
self.len() == 0
}
/// Returns the atom as a mutable pointer.
#[inline]
pub fn as_ptr(&self) -> *mut nsAtom {
let const_ptr: *const nsAtom = &self.0;
const_ptr as *mut nsAtom
}
/// Convert this atom to ASCII lower-case
pub fn to_ascii_lowercase(&self) -> Atom {
if self.is_ascii_lowercase() {
return self.clone();
}
let slice = self.as_slice();
let mut buffer = mem::MaybeUninit::<[u16; 64]>::uninit();
let buffer = unsafe { &mut *buffer.as_mut_ptr() };
let mut vec;
let mutable_slice = if let Some(buffer_prefix) = buffer.get_mut(..slice.len()) {
buffer_prefix.copy_from_slice(slice);
buffer_prefix
} else {
vec = slice.to_vec();
&mut vec
};
for char16 in &mut *mutable_slice {
if *char16 <= 0x7F {
*char16 = (*char16 as u8).to_ascii_lowercase() as u16
}
}
Atom::from(&*mutable_slice)
}
/// Return whether two atoms are ASCII-case-insensitive matches
#[inline]
pub fn eq_ignore_ascii_case(&self, other: &Self) -> bool {
if self == other {
return true;
}
// If we know both atoms are ascii-lowercase, then we can stick with
// pointer equality.
if self.is_ascii_lowercase() && other.is_ascii_lowercase() {
debug_assert!(!self.eq_ignore_ascii_case_slow(other));
return false;
}
self.eq_ignore_ascii_case_slow(other)
}
fn eq_ignore_ascii_case_slow(&self, other: &Self) -> bool {
let a = self.as_slice();
let b = other.as_slice();
if a.len() != b.len() {
return false;
}
a.iter().zip(b).all(|(&a16, &b16)| {
if a16 <= 0x7F && b16 <= 0x7F {
(a16 as u8).eq_ignore_ascii_case(&(b16 as u8))
} else {
a16 == b16
}
})
}
}
impl fmt::Debug for WeakAtom {
fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
write!(w, "Gecko WeakAtom({:p}, {})", self, self)
}
}
impl fmt::Display for WeakAtom {
fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
for c in self.chars() {
w.write_char(c.unwrap_or(char::REPLACEMENT_CHARACTER))?
}
Ok(())
}
}
#[inline]
unsafe fn make_handle(ptr: *const nsAtom) -> NonZeroUsize {
debug_assert!(!ptr.is_null());
if !WeakAtom::new(ptr).is_static() {
NonZeroUsize::new_unchecked(ptr as usize)
} else {
make_static_handle(ptr as *mut nsStaticAtom)
}
}
#[inline]
unsafe fn make_static_handle(ptr: *const nsStaticAtom) -> NonZeroUsize {
let index = ptr.offset_from(&gGkAtoms.mAtoms[0] as *const _);
debug_assert!(index >= 0, "Should be a non-negative index");
debug_assert!(
(index as usize) < STATIC_ATOM_COUNT,
"Should be a valid static atom index"
);
NonZeroUsize::new_unchecked(((index as usize) << 1) | 1)
}
impl Atom {
#[inline]
fn is_static(&self) -> bool {
self.0.get() & 1 == 1
}
/// Execute a callback with the atom represented by `ptr`.
pub unsafe fn with<F, R>(ptr: *const nsAtom, callback: F) -> R
where
F: FnOnce(&Atom) -> R,
{
let atom = Atom(make_handle(ptr as *mut nsAtom));
let ret = callback(&atom);
mem::forget(atom);
ret
}
/// Creates a static atom from its index in the static atom table, without
/// checking.
#[inline]
pub const unsafe fn from_index_unchecked(index: u16) -> Self {
debug_assert!((index as usize) < STATIC_ATOM_COUNT);
Atom(NonZeroUsize::new_unchecked(((index as usize) << 1) | 1))
}
/// Creates an atom from an atom pointer.
#[inline(always)]
pub unsafe fn from_raw(ptr: *mut nsAtom) -> Self {
let atom = Atom(make_handle(ptr));
if !atom.is_static() {
Gecko_AddRefAtom(ptr);
}
atom
}
/// Creates an atom from an atom pointer that has already had AddRef
/// called on it. This may be a static or dynamic atom.
#[inline]
pub unsafe fn from_addrefed(ptr: *mut nsAtom) -> Self {
assert!(!ptr.is_null());
Atom(make_handle(ptr))
}
/// Convert this atom into an addrefed nsAtom pointer.
#[inline]
pub fn into_addrefed(self) -> *mut nsAtom {
let ptr = self.as_ptr();
mem::forget(self);
ptr
}
}
impl Hash for Atom {
fn hash<H>(&self, state: &mut H)
where
H: Hasher,
{
state.write_u32(self.get_hash());
}
}
impl Hash for WeakAtom {
fn hash<H>(&self, state: &mut H)
where
H: Hasher,
{
state.write_u32(self.get_hash());
}
}
impl Clone for Atom {
#[inline(always)]
fn clone(&self) -> Atom {
unsafe {
let atom = Atom(self.0);
if !atom.is_static() {
Gecko_AddRefAtom(atom.as_ptr());
}
atom
}
}
}
impl Drop for Atom {
#[inline]
fn drop(&mut self) {
if !self.is_static() {
unsafe {
Gecko_ReleaseAtom(self.as_ptr());
}
}
}
}
impl Default for Atom {
#[inline]
fn default() -> Self {
atom!("")
}
}
impl fmt::Debug for Atom {
fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
write!(w, "Atom(0x{:08x}, {})", self.0, self)
}
}
impl fmt::Display for Atom {
fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
self.deref().fmt(w)
}
}
impl<'a> From<&'a str> for Atom {
#[inline]
fn from(string: &str) -> Atom {
debug_assert!(string.len() <= u32::max_value() as usize);
unsafe {
Atom::from_addrefed(Gecko_Atomize(
string.as_ptr() as *const _,
string.len() as u32,
))
}
}
}
impl<'a> From<&'a [u16]> for Atom {
#[inline]
fn from(slice: &[u16]) -> Atom {
Atom::from(&*nsStr::from(slice))
}
}
impl<'a> From<&'a nsAString> for Atom {
#[inline]
fn from(string: &nsAString) -> Atom {
unsafe { Atom::from_addrefed(Gecko_Atomize16(string)) }
}
}
impl<'a> From<Cow<'a, str>> for Atom {
#[inline]
fn from(string: Cow<'a, str>) -> Atom {
Atom::from(&*string)
}
}
impl From<String> for Atom {
#[inline]
fn from(string: String) -> Atom {
Atom::from(&*string)
}
}
malloc_size_of_is_0!(Atom);
impl SpecifiedValueInfo for Atom {}