tor-browser

lib.rs (17326B)

---

// Copyright 2016-2017 The Servo Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

//! A reduced fork of Firefox's malloc_size_of crate, for bundling with WebRender.

#[cfg(feature = "app_units")]
extern crate app_units;
#[cfg(feature = "euclid")]
extern crate euclid;

use std::collections::{BTreeMap, BTreeSet};
use std::hash::{BuildHasher, Hash};
use std::mem::size_of;
use std::ops::Range;
use std::os::raw::c_void;
use std::path::PathBuf;

/// A C function that takes a pointer to a heap allocation and returns its size.
type VoidPtrToSizeFn = unsafe extern "C" fn(ptr: *const c_void) -> usize;

/// Operations used when measuring heap usage of data structures.
pub struct MallocSizeOfOps {
   /// A function that returns the size of a heap allocation.
   pub size_of_op: VoidPtrToSizeFn,

   /// Like `size_of_op`, but can take an interior pointer. Optional because
   /// not all allocators support this operation. If it's not provided, some
   /// memory measurements will actually be computed estimates rather than
   /// real and accurate measurements.
   pub enclosing_size_of_op: Option<VoidPtrToSizeFn>,
}

impl MallocSizeOfOps {
   pub fn new(
       size_of: VoidPtrToSizeFn,
       malloc_enclosing_size_of: Option<VoidPtrToSizeFn>,
   ) -> Self {
       MallocSizeOfOps {
           size_of_op: size_of,
           enclosing_size_of_op: malloc_enclosing_size_of,
       }
   }

   /// Check if an allocation is empty. This relies on knowledge of how Rust
   /// handles empty allocations, which may change in the future.
   fn is_empty<T: ?Sized>(ptr: *const T) -> bool {
       // The correct condition is this:
       //   `ptr as usize <= ::std::mem::align_of::<T>()`
       // But we can't call align_of() on a ?Sized T. So we approximate it
       // with the following. 256 is large enough that it should always be
       // larger than the required alignment, but small enough that it is
       // always in the first page of memory and therefore not a legitimate
       // address.
       ptr as *const usize as usize <= 256
   }

   /// Call `size_of_op` on `ptr`, first checking that the allocation isn't
   /// empty, because some types (such as `Vec`) utilize empty allocations.
   pub unsafe fn malloc_size_of<T: ?Sized>(&self, ptr: *const T) -> usize {
       if MallocSizeOfOps::is_empty(ptr) {
           0
       } else {
           (self.size_of_op)(ptr as *const c_void)
       }
   }

   /// Is an `enclosing_size_of_op` available?
   pub fn has_malloc_enclosing_size_of(&self) -> bool {
       self.enclosing_size_of_op.is_some()
   }

   /// Call `enclosing_size_of_op`, which must be available, on `ptr`, which
   /// must not be empty.
   pub unsafe fn malloc_enclosing_size_of<T>(&self, ptr: *const T) -> usize {
       assert!(!MallocSizeOfOps::is_empty(ptr));
       (self.enclosing_size_of_op.unwrap())(ptr as *const c_void)
   }
}

/// Trait for measuring the "deep" heap usage of a data structure. This is the
/// most commonly-used of the traits.
pub trait MallocSizeOf {
   /// Measure the heap usage of all descendant heap-allocated structures, but
   /// not the space taken up by the value itself.
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize;
}

/// Trait for measuring the "shallow" heap usage of a container.
pub trait MallocShallowSizeOf {
   /// Measure the heap usage of immediate heap-allocated descendant
   /// structures, but not the space taken up by the value itself. Anything
   /// beyond the immediate descendants must be measured separately, using
   /// iteration.
   fn shallow_size_of(&self, ops: &mut MallocSizeOfOps) -> usize;
}

impl MallocSizeOf for String {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       unsafe { ops.malloc_size_of(self.as_ptr()) }
   }
}

impl<T: ?Sized> MallocShallowSizeOf for Box<T> {
   fn shallow_size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       unsafe { ops.malloc_size_of(&**self) }
   }
}

impl<T: MallocSizeOf + ?Sized> MallocSizeOf for Box<T> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       self.shallow_size_of(ops) + (**self).size_of(ops)
   }
}

impl MallocSizeOf for () {
   fn size_of(&self, _ops: &mut MallocSizeOfOps) -> usize {
       0
   }
}

impl<T1, T2> MallocSizeOf for (T1, T2)
where
   T1: MallocSizeOf,
   T2: MallocSizeOf,
{
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       self.0.size_of(ops) + self.1.size_of(ops)
   }
}

impl<T1, T2, T3> MallocSizeOf for (T1, T2, T3)
where
   T1: MallocSizeOf,
   T2: MallocSizeOf,
   T3: MallocSizeOf,
{
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       self.0.size_of(ops) + self.1.size_of(ops) + self.2.size_of(ops)
   }
}

impl<T1, T2, T3, T4> MallocSizeOf for (T1, T2, T3, T4)
where
   T1: MallocSizeOf,
   T2: MallocSizeOf,
   T3: MallocSizeOf,
   T4: MallocSizeOf,
{
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       self.0.size_of(ops) + self.1.size_of(ops) + self.2.size_of(ops) + self.3.size_of(ops)
   }
}

impl<T: MallocSizeOf> MallocSizeOf for Option<T> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       if let Some(val) = self.as_ref() {
           val.size_of(ops)
       } else {
           0
       }
   }
}

impl<T: MallocSizeOf, E: MallocSizeOf> MallocSizeOf for Result<T, E> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       match *self {
           Ok(ref x) => x.size_of(ops),
           Err(ref e) => e.size_of(ops),
       }
   }
}

impl<T: MallocSizeOf + Copy> MallocSizeOf for std::cell::Cell<T> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       self.get().size_of(ops)
   }
}

impl<T: MallocSizeOf> MallocSizeOf for std::cell::RefCell<T> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       self.borrow().size_of(ops)
   }
}

impl<'a, B: ?Sized + ToOwned> MallocSizeOf for std::borrow::Cow<'a, B>
where
   B::Owned: MallocSizeOf,
{
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       match *self {
           std::borrow::Cow::Borrowed(_) => 0,
           std::borrow::Cow::Owned(ref b) => b.size_of(ops),
       }
   }
}

impl<T: MallocSizeOf> MallocSizeOf for [T] {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       let mut n = 0;
       for elem in self.iter() {
           n += elem.size_of(ops);
       }
       n
   }
}

impl<T> MallocShallowSizeOf for Vec<T> {
   fn shallow_size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       unsafe { ops.malloc_size_of(self.as_ptr()) }
   }
}

impl<T: MallocSizeOf> MallocSizeOf for Vec<T> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       let mut n = self.shallow_size_of(ops);
       for elem in self.iter() {
           n += elem.size_of(ops);
       }
       n
   }
}

macro_rules! malloc_size_of_hash_set {
   ($ty:ty) => {
       impl<T, S> MallocShallowSizeOf for $ty
       where
           T: Eq + Hash,
           S: BuildHasher,
       {
           fn shallow_size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
               if ops.has_malloc_enclosing_size_of() {
                   // The first value from the iterator gives us an interior pointer.
                   // `ops.malloc_enclosing_size_of()` then gives us the storage size.
                   // This assumes that the `HashSet`'s contents (values and hashes)
                   // are all stored in a single contiguous heap allocation.
                   self.iter()
                       .next()
                       .map_or(0, |t| unsafe { ops.malloc_enclosing_size_of(t) })
               } else {
                   // An estimate.
                   self.capacity() * (size_of::<T>() + size_of::<usize>())
               }
           }
       }

       impl<T, S> MallocSizeOf for $ty
       where
           T: Eq + Hash + MallocSizeOf,
           S: BuildHasher,
       {
           fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
               let mut n = self.shallow_size_of(ops);
               for t in self.iter() {
                   n += t.size_of(ops);
               }
               n
           }
       }
   };
}

malloc_size_of_hash_set!(std::collections::HashSet<T, S>);

macro_rules! malloc_size_of_hash_map {
   ($ty:ty) => {
       impl<K, V, S> MallocShallowSizeOf for $ty
       where
           K: Eq + Hash,
           S: BuildHasher,
       {
           fn shallow_size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
               // See the implementation for std::collections::HashSet for details.
               if ops.has_malloc_enclosing_size_of() {
                   self.values()
                       .next()
                       .map_or(0, |v| unsafe { ops.malloc_enclosing_size_of(v) })
               } else {
                   self.capacity() * (size_of::<V>() + size_of::<K>() + size_of::<usize>())
               }
           }
       }

       impl<K, V, S> MallocSizeOf for $ty
       where
           K: Eq + Hash + MallocSizeOf,
           V: MallocSizeOf,
           S: BuildHasher,
       {
           fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
               let mut n = self.shallow_size_of(ops);
               for (k, v) in self.iter() {
                   n += k.size_of(ops);
                   n += v.size_of(ops);
               }
               n
           }
       }
   };
}

malloc_size_of_hash_map!(std::collections::HashMap<K, V, S>);

impl<K, V> MallocShallowSizeOf for BTreeMap<K, V> {
   fn shallow_size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       if ops.has_malloc_enclosing_size_of() {
           self.values()
               .next()
               .map_or(0, |v| unsafe { ops.malloc_enclosing_size_of(v) })
       } else {
           self.len() * (size_of::<V>() + size_of::<K>() + size_of::<usize>())
       }
   }
}

impl<K, V> MallocSizeOf for BTreeMap<K, V>
where
   K: MallocSizeOf,
   V: MallocSizeOf,
{
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       let mut n = self.shallow_size_of(ops);
       for (k, v) in self.iter() {
           n += k.size_of(ops);
           n += v.size_of(ops);
       }
       n
   }
}

impl<T> MallocShallowSizeOf for BTreeSet<T> {
   fn shallow_size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       if ops.has_malloc_enclosing_size_of() {
           self.iter()
               .next()
               .map_or(0, |v| unsafe { ops.malloc_enclosing_size_of(v) })
       } else {
           self.len() * (size_of::<T>() + size_of::<usize>())
       }
   }
}

impl<T> MallocSizeOf for BTreeSet<T>
where
   T: MallocSizeOf,
{
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       let mut n = self.shallow_size_of(ops);
       for v in self.iter() {
           n += v.size_of(ops);
       }
       n
   }
}

// PhantomData is always 0.
impl<T> MallocSizeOf for std::marker::PhantomData<T> {
   fn size_of(&self, _ops: &mut MallocSizeOfOps) -> usize {
       0
   }
}

impl MallocSizeOf for PathBuf {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       match self.to_str() {
           Some(s) => unsafe { ops.malloc_size_of(s.as_ptr()) },
           None => self.as_os_str().len(),
       }
   }
}

#[cfg(feature = "euclid")]
impl<T: MallocSizeOf, Unit> MallocSizeOf for euclid::Length<T, Unit> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       self.0.size_of(ops)
   }
}

#[cfg(feature = "euclid")]
impl<T: MallocSizeOf, Src, Dst> MallocSizeOf for euclid::Scale<T, Src, Dst> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       self.0.size_of(ops)
   }
}

#[cfg(feature = "euclid")]
impl<T: MallocSizeOf, U> MallocSizeOf for euclid::Point2D<T, U> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       self.x.size_of(ops) + self.y.size_of(ops)
   }
}

#[cfg(feature = "euclid")]
impl<T: MallocSizeOf, U> MallocSizeOf for euclid::Rect<T, U> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       self.origin.size_of(ops) + self.size.size_of(ops)
   }
}

#[cfg(feature = "euclid")]
impl<T: MallocSizeOf, U> MallocSizeOf for euclid::Box2D<T, U> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       self.min.size_of(ops) + self.max.size_of(ops)
   }
}

#[cfg(feature = "euclid")]
impl<T: MallocSizeOf, U> MallocSizeOf for euclid::SideOffsets2D<T, U> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       self.top.size_of(ops) +
           self.right.size_of(ops) +
           self.bottom.size_of(ops) +
           self.left.size_of(ops)
   }
}

#[cfg(feature = "euclid")]
impl<T: MallocSizeOf, U> MallocSizeOf for euclid::Size2D<T, U> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       self.width.size_of(ops) + self.height.size_of(ops)
   }
}

#[cfg(feature = "euclid")]
impl<T: MallocSizeOf, Src, Dst> MallocSizeOf for euclid::Transform2D<T, Src, Dst> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       self.m11.size_of(ops) +
           self.m12.size_of(ops) +
           self.m21.size_of(ops) +
           self.m22.size_of(ops) +
           self.m31.size_of(ops) +
           self.m32.size_of(ops)
   }
}

#[cfg(feature = "euclid")]
impl<T: MallocSizeOf, Src, Dst> MallocSizeOf for euclid::Transform3D<T, Src, Dst> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       self.m11.size_of(ops) +
           self.m12.size_of(ops) +
           self.m13.size_of(ops) +
           self.m14.size_of(ops) +
           self.m21.size_of(ops) +
           self.m22.size_of(ops) +
           self.m23.size_of(ops) +
           self.m24.size_of(ops) +
           self.m31.size_of(ops) +
           self.m32.size_of(ops) +
           self.m33.size_of(ops) +
           self.m34.size_of(ops) +
           self.m41.size_of(ops) +
           self.m42.size_of(ops) +
           self.m43.size_of(ops) +
           self.m44.size_of(ops)
   }
}

#[cfg(feature = "euclid")]
impl<T: MallocSizeOf, U> MallocSizeOf for euclid::Vector2D<T, U> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       self.x.size_of(ops) + self.y.size_of(ops)
   }
}

/// For use on types where size_of() returns 0.
#[macro_export]
macro_rules! malloc_size_of_is_0(
   ($($ty:ty),+) => (
       $(
           impl $crate::MallocSizeOf for $ty {
               #[inline(always)]
               fn size_of(&self, _: &mut $crate::MallocSizeOfOps) -> usize {
                   0
               }
           }
       )+
   );
   ($($ty:ident<$($gen:ident),+>),+) => (
       $(
       impl<$($gen: $crate::MallocSizeOf),+> $crate::MallocSizeOf for $ty<$($gen),+> {
           #[inline(always)]
           fn size_of(&self, _: &mut $crate::MallocSizeOfOps) -> usize {
               0
           }
       }
       )+
   );
);

malloc_size_of_is_0!(bool, char, str);
malloc_size_of_is_0!(u8, u16, u32, u64, u128, usize);
malloc_size_of_is_0!(i8, i16, i32, i64, i128, isize);
malloc_size_of_is_0!(f32, f64);

malloc_size_of_is_0!(std::sync::atomic::AtomicBool);
malloc_size_of_is_0!(std::sync::atomic::AtomicIsize);
malloc_size_of_is_0!(std::sync::atomic::AtomicUsize);
malloc_size_of_is_0!(
   std::sync::atomic::AtomicU8,
   std::sync::atomic::AtomicU16,
   std::sync::atomic::AtomicU32,
   std::sync::atomic::AtomicU64
);
malloc_size_of_is_0!(
   std::sync::atomic::AtomicI8,
   std::sync::atomic::AtomicI16,
   std::sync::atomic::AtomicI32,
   std::sync::atomic::AtomicI64
);

malloc_size_of_is_0!(std::num::NonZeroUsize);
malloc_size_of_is_0!(std::num::NonZeroU32);

malloc_size_of_is_0!(std::time::Duration);
malloc_size_of_is_0!(std::time::Instant);
malloc_size_of_is_0!(std::time::SystemTime);

malloc_size_of_is_0!(Range<u8>, Range<u16>, Range<u32>, Range<u64>, Range<usize>);
malloc_size_of_is_0!(Range<i8>, Range<i16>, Range<i32>, Range<i64>, Range<isize>);
malloc_size_of_is_0!(Range<f32>, Range<f64>);

#[cfg(feature = "app_units")]
malloc_size_of_is_0!(app_units::Au);

#[cfg(feature = "once_cell")]
impl<T: MallocSizeOf, F: FnOnce() -> T> MallocSizeOf for once_cell::sync::Lazy<T, F> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       once_cell::sync::Lazy::get(self).map(|obj| obj.size_of(ops)).unwrap_or(0)
   }
}

#[cfg(feature = "once_cell")]
impl<T: MallocSizeOf> MallocSizeOf for once_cell::sync::OnceCell<T> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       once_cell::sync::OnceCell::get(self).map(|obj| obj.size_of(ops)).unwrap_or(0)
   }
}

#[cfg(feature = "once_cell")]
impl<T: MallocSizeOf, F: FnOnce() -> T> MallocSizeOf for &'static once_cell::sync::Lazy<T, F> {
   fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
       once_cell::sync::Lazy::get(self).map(|obj| obj.size_of(ops)).unwrap_or(0)
   }
}