Auto merge of #18334 - Manishearth:hashglobe, r=emilio,Gankro

Add fallible hashmaps from HashGlobe for stylo

HashGlobe code is r=emilio,Gankro

integration code is r=emilio from https://bugzilla.mozilla.org/show_bug.cgi?id=1393656

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Cargo.lock

@@ -1242,6 +1242,15 @@ dependencies = [
  "pkg-config 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "hashglobe"
+version = "0.1.0"
+dependencies = [
+ "heapsize 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "heapsize"
 version = "0.4.0"
@@ -3078,6 +3087,7 @@ dependencies = [
  "encoding 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.15.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hashglobe 0.1.0",
  "heapsize 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "heapsize_derive 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "html5ever 0.19.0 (registry+https://github.com/rust-lang/crates.io-index)",

components/hashglobe/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "hashglobe"
+version = "0.1.0"
+authors = ["The Rust Project Developers", "Manish Goregaokar <manishsmail@gmail.com>"]
+license = "MIT/Apache-2.0"
+description = "Fork of std::HashMap with stable fallible allocation."
+documentation = "https://docs.rs/hashglobe"
+repository = "https://github.com/Manishearth/hashglobe"
+
+readme = "README.md"
+
+[dependencies]
+libc = "0.2"
+heapsize = "0.4"
+
+[dev-dependencies]
+rand = "0.3"

components/hashglobe/LICENSE-APACHE

@@ -0,0 +1,201 @@
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components/hashglobe/LICENSE-MIT

@@ -0,0 +1,23 @@
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
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+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.

components/hashglobe/README.md

@@ -0,0 +1,17 @@
+hashglobe
+========
+
+
+This is a fork of Rust's `std::HashMap`. It works on stable out of the stdlib and has fallible APIs.
+
+We intend to diverge as little as possible from the original hashmap.
+
+
+Dual licensed Apache/MIT, the same as the stdlib.
+
+
+## Should I use this?
+
+No.
+
+Wait for https://github.com/rust-lang/rfcs/pull/2116 instead.

components/hashglobe/src/alloc.rs

@@ -0,0 +1,152 @@
+// FORK NOTE: Copied from liballoc_system, removed unnecessary APIs,
+// APIs take size/align directly instead of Layout
+
+
+
+
+// The minimum alignment guaranteed by the architecture. This value is used to
+// add fast paths for low alignment values. In practice, the alignment is a
+// constant at the call site and the branch will be optimized out.
+#[cfg(all(any(target_arch = "x86",
+              target_arch = "arm",
+              target_arch = "mips",
+              target_arch = "powerpc",
+              target_arch = "powerpc64",
+              target_arch = "asmjs",
+              target_arch = "wasm32")))]
+const MIN_ALIGN: usize = 8;
+#[cfg(all(any(target_arch = "x86_64",
+              target_arch = "aarch64",
+              target_arch = "mips64",
+              target_arch = "s390x",
+              target_arch = "sparc64")))]
+const MIN_ALIGN: usize = 16;
+
+pub use self::platform::{alloc, dealloc};
+
+#[cfg(any(unix, target_os = "redox"))]
+mod platform {
+    extern crate libc;
+
+    use std::ptr;
+
+    use super::MIN_ALIGN;
+
+    #[inline]
+    pub unsafe fn alloc(size: usize, align: usize) -> *mut u8 {
+        let ptr = if align <= MIN_ALIGN {
+            libc::malloc(size) as *mut u8
+        } else {
+            aligned_malloc(size, align)
+        };
+        ptr
+    }
+
+    #[inline]
+    pub unsafe fn dealloc(ptr: *mut u8, _align: usize) {
+        libc::free(ptr as *mut libc::c_void)
+    }
+
+    #[cfg(any(target_os = "android", target_os = "redox"))]
+    #[inline]
+    unsafe fn aligned_malloc(size: usize, align: usize) -> *mut u8 {
+        // On android we currently target API level 9 which unfortunately
+        // doesn't have the `posix_memalign` API used below. Instead we use
+        // `memalign`, but this unfortunately has the property on some systems
+        // where the memory returned cannot be deallocated by `free`!
+        //
+        // Upon closer inspection, however, this appears to work just fine with
+        // Android, so for this platform we should be fine to call `memalign`
+        // (which is present in API level 9). Some helpful references could
+        // possibly be chromium using memalign [1], attempts at documenting that
+        // memalign + free is ok [2] [3], or the current source of chromium
+        // which still uses memalign on android [4].
+        //
+        // [1]: https://codereview.chromium.org/10796020/
+        // [2]: https://code.google.com/p/android/issues/detail?id=35391
+        // [3]: https://bugs.chromium.org/p/chromium/issues/detail?id=138579
+        // [4]: https://chromium.googlesource.com/chromium/src/base/+/master/
+        //                                       /memory/aligned_memory.cc
+        libc::memalign(align, size) as *mut u8
+    }
+
+    #[cfg(not(any(target_os = "android", target_os = "redox")))]
+    #[inline]
+    unsafe fn aligned_malloc(size: usize, align: usize) -> *mut u8 {
+        let mut out = ptr::null_mut();
+        let ret = libc::posix_memalign(&mut out, align, size);
+        if ret != 0 {
+            ptr::null_mut()
+        } else {
+            out as *mut u8
+        }
+    }
+}
+
+#[cfg(windows)]
+#[allow(bad_style)]
+mod platform {
+
+    use super::MIN_ALIGN;
+    type LPVOID = *mut u8;
+    type HANDLE = LPVOID;
+    type SIZE_T = usize;
+    type DWORD = u32;
+    type BOOL = i32;
+
+
+    extern "system" {
+        fn GetProcessHeap() -> HANDLE;
+        fn HeapAlloc(hHeap: HANDLE, dwFlags: DWORD, dwBytes: SIZE_T) -> LPVOID;
+        fn HeapFree(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID) -> BOOL;
+        fn GetLastError() -> DWORD;
+    }
+
+    #[repr(C)]
+    struct Header(*mut u8);
+
+    unsafe fn get_header<'a>(ptr: *mut u8) -> &'a mut Header {
+        &mut *(ptr as *mut Header).offset(-1)
+    }
+
+    unsafe fn align_ptr(ptr: *mut u8, align: usize) -> *mut u8 {
+        let aligned = ptr.offset((align - (ptr as usize & (align - 1))) as isize);
+        *get_header(aligned) = Header(ptr);
+        aligned
+    }
+
+    #[inline]
+    unsafe fn allocate_with_flags(size: usize, align: usize, flags: DWORD) -> *mut u8
+    {
+        if align <= MIN_ALIGN {
+            HeapAlloc(GetProcessHeap(), flags, size)
+        } else {
+            let size = size + align;
+            let ptr = HeapAlloc(GetProcessHeap(), flags, size);
+            if ptr.is_null() {
+                ptr
+            } else {
+                align_ptr(ptr, align)
+            }
+        }
+    }
+
+    #[inline]
+    pub unsafe fn alloc(size: usize, align: usize) -> *mut u8 {
+        allocate_with_flags(size, align, 0)
+    }
+
+    #[inline]
+    pub unsafe fn dealloc(ptr: *mut u8, align: usize) {
+        if align <= MIN_ALIGN {
+            let err = HeapFree(GetProcessHeap(), 0, ptr as LPVOID);
+            debug_assert!(err != 0, "Failed to free heap memory: {}",
+                          GetLastError());
+        } else {
+            let header = get_header(ptr);
+            let err = HeapFree(GetProcessHeap(), 0, header.0 as LPVOID);
+            debug_assert!(err != 0, "Failed to free heap memory: {}",
+                          GetLastError());
+        }
+    }
+}

components/hashglobe/src/fake.rs

@@ -0,0 +1,294 @@
+// Copyright 2014-2015 The Rust 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.
+
+//! This module contains shims around the stdlib HashMap
+//! that add fallible methods
+//!
+//! These methods are a lie. They are not actually fallible. This is just to make
+//! it smooth to switch between hashmap impls in a codebase.
+
+use heapsize::HeapSizeOf;
+use std::collections::HashMap as StdMap;
+use std::collections::HashSet as StdSet;
+use std::fmt;
+use std::hash::{BuildHasher, Hash};
+use std::ops::{Deref, DerefMut};
+
+pub use std::collections::hash_map::{Entry, RandomState, Iter as MapIter, IterMut as MapIterMut};
+pub use std::collections::hash_set::{Iter as SetIter, IntoIter as SetIntoIter};
+
+#[derive(Clone)]
+pub struct HashMap<K, V, S = RandomState>(StdMap<K, V, S>);
+
+
+use FailedAllocationError;
+
+impl<K, V, S> Deref for HashMap<K, V, S> {
+    type Target = StdMap<K, V, S>;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<K, V, S> DerefMut for HashMap<K, V, S> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+impl<K: Hash + Eq, V> HashMap<K, V, RandomState> {
+    #[inline]
+    pub fn new() -> HashMap<K, V, RandomState> {
+        HashMap(StdMap::new())
+    }
+
+    #[inline]
+    pub fn with_capacity(capacity: usize) -> HashMap<K, V, RandomState> {
+        HashMap(StdMap::with_capacity(capacity))
+    }
+
+    #[inline]
+    pub fn try_with_capacity(capacity: usize) -> Result<HashMap<K, V, RandomState>, FailedAllocationError> {
+        Ok(HashMap(StdMap::with_capacity(capacity)))
+    }
+}
+
+
+impl<K, V, S> HashMap<K, V, S>
+    where K: Eq + Hash,
+          S: BuildHasher
+{
+    #[inline]
+    pub fn try_with_hasher(hash_builder: S) -> Result<HashMap<K, V, S>, FailedAllocationError> {
+        Ok(HashMap(StdMap::with_hasher(hash_builder)))
+    }
+
+    #[inline]
+    pub fn try_with_capacity_and_hasher(capacity: usize,
+                                        hash_builder: S)
+        -> Result<HashMap<K, V, S>, FailedAllocationError> {
+        Ok(HashMap(StdMap::with_capacity_and_hasher(capacity, hash_builder)))
+    }
+
+    pub fn with_capacity_and_hasher(capacity: usize, hash_builder: S) -> HashMap<K, V, S> {
+        HashMap(StdMap::with_capacity_and_hasher(capacity, hash_builder))
+    }
+
+
+    #[inline]
+    pub fn try_reserve(&mut self, additional: usize) -> Result<(), FailedAllocationError> {
+        Ok(self.reserve(additional))
+    }
+
+    pub fn try_shrink_to_fit(&mut self) -> Result<(), FailedAllocationError> {
+        Ok(self.shrink_to_fit())
+    }
+
+    pub fn try_entry(&mut self, key: K) -> Result<Entry<K, V>, FailedAllocationError> {
+        Ok(self.entry(key))
+    }
+
+    #[inline]
+    pub fn try_insert(&mut self, k: K, v: V) -> Result<Option<V>, FailedAllocationError> {
+        Ok(self.insert(k, v))
+    }
+}
+
+#[derive(Clone)]
+pub struct HashSet<T, S = RandomState>(StdSet<T, S>);
+
+
+impl<T, S> Deref for HashSet<T, S> {
+    type Target = StdSet<T, S>;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<T, S> DerefMut for HashSet<T, S> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+impl<T: Hash + Eq> HashSet<T, RandomState> {
+    #[inline]
+    pub fn new() -> HashSet<T, RandomState> {
+        HashSet(StdSet::new())
+    }
+
+    #[inline]
+    pub fn with_capacity(capacity: usize) -> HashSet<T, RandomState> {
+        HashSet(StdSet::with_capacity(capacity))
+    }
+}
+
+
+impl<T, S> HashSet<T, S>
+    where T: Eq + Hash,
+          S: BuildHasher
+{
+    #[inline]
+    pub fn with_hasher(hasher: S) -> HashSet<T, S> {
+        HashSet(StdSet::with_hasher(hasher))
+    }
+
+
+    #[inline]
+    pub fn with_capacity_and_hasher(capacity: usize, hasher: S) -> HashSet<T, S> {
+        HashSet(StdSet::with_capacity_and_hasher(capacity, hasher))
+    }
+
+    #[inline]
+    pub fn try_reserve(&mut self, additional: usize) -> Result<(), FailedAllocationError> {
+        Ok(self.reserve(additional))
+    }
+
+    #[inline]
+    pub fn try_shrink_to_fit(&mut self) -> Result<(), FailedAllocationError> {
+        Ok(self.shrink_to_fit())
+    }
+
+    #[inline]
+    pub fn try_insert(&mut self, value: T) -> Result<bool, FailedAllocationError> {
+        Ok(self.insert(value))
+    }
+}
+
+// Pass through trait impls
+// We can't derive these since the bounds are not obvious to the derive macro
+
+
+impl<K: HeapSizeOf + Hash + Eq, V: HeapSizeOf, S: BuildHasher>
+        HeapSizeOf for HashMap<K, V, S> {
+    fn heap_size_of_children(&self) -> usize {
+        self.0.heap_size_of_children()
+    }
+}
+
+impl<K: Hash + Eq, V, S: BuildHasher + Default> Default for HashMap<K, V, S> {
+    fn default() -> Self {
+        HashMap(Default::default())
+    }
+}
+
+impl<K, V, S> fmt::Debug for HashMap<K, V, S>
+    where K: Eq + Hash + fmt::Debug,
+          V: fmt::Debug,
+          S: BuildHasher {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+impl<K, V, S> PartialEq for HashMap<K, V, S>
+    where K: Eq + Hash,
+          V: PartialEq,
+          S: BuildHasher
+{
+    fn eq(&self, other: &HashMap<K, V, S>) -> bool {
+        self.0.eq(&other.0)
+    }
+}
+
+impl<K, V, S> Eq for HashMap<K, V, S>
+    where K: Eq + Hash,
+          V: Eq,
+          S: BuildHasher
+{
+}
+
+impl<'a, K, V, S> IntoIterator for &'a HashMap<K, V, S>
+    where K: Eq + Hash,
+          S: BuildHasher
+{
+    type Item = (&'a K, &'a V);
+    type IntoIter = MapIter<'a, K, V>;
+
+    fn into_iter(self) -> MapIter<'a, K, V> {
+        self.0.iter()
+    }
+}
+
+impl<'a, K, V, S> IntoIterator for &'a mut HashMap<K, V, S>
+    where K: Eq + Hash,
+          S: BuildHasher
+{
+    type Item = (&'a K, &'a mut V);
+    type IntoIter = MapIterMut<'a, K, V>;
+
+    fn into_iter(self) -> MapIterMut<'a, K, V> {
+        self.0.iter_mut()
+    }
+}
+
+
+impl<T: HeapSizeOf + Eq + Hash, S: BuildHasher> HeapSizeOf for HashSet<T, S> {
+    fn heap_size_of_children(&self) -> usize {
+        self.0.heap_size_of_children()
+    }
+}
+
+impl<T: Eq + Hash, S: BuildHasher + Default> Default for HashSet<T, S> {
+    fn default() -> Self {
+        HashSet(Default::default())
+    }
+}
+
+impl<T, S> fmt::Debug for HashSet<T, S>
+    where T: Eq + Hash + fmt::Debug,
+          S: BuildHasher
+{
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+impl<T, S> PartialEq for HashSet<T, S>
+    where T: Eq + Hash,
+          S: BuildHasher
+{
+    fn eq(&self, other: &HashSet<T, S>) -> bool {
+        self.0.eq(&other.0)
+    }
+}
+
+impl<T, S> Eq for HashSet<T, S>
+    where T: Eq + Hash,
+          S: BuildHasher
+{
+}
+
+impl<'a, T, S> IntoIterator for &'a HashSet<T, S>
+    where T: Eq + Hash,
+          S: BuildHasher
+{
+    type Item = &'a T;
+    type IntoIter = SetIter<'a, T>;
+
+    fn into_iter(self) -> SetIter<'a, T> {
+        self.0.iter()
+    }
+}
+
+impl<T, S> IntoIterator for HashSet<T, S>
+    where T: Eq + Hash,
+          S: BuildHasher
+{
+    type Item = T;
+    type IntoIter = SetIntoIter<T>;
+
+
+    fn into_iter(self) -> SetIntoIter<T> {
+        self.0.into_iter()
+    }
+}
+
+

components/hashglobe/src/lib.rs

@@ -0,0 +1,48 @@
+// Copyright 2014-2015 The Rust 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.
+
+pub use std::*;
+
+extern crate heapsize;
+
+mod alloc;
+pub mod hash_map;
+pub mod hash_set;
+mod shim;
+mod table;
+
+pub mod fake;
+
+use std::{error, fmt};
+
+trait Recover<Q: ?Sized> {
+    type Key;
+
+    fn get(&self, key: &Q) -> Option<&Self::Key>;
+    fn take(&mut self, key: &Q) -> Option<Self::Key>;
+    fn replace(&mut self, key: Self::Key) -> Option<Self::Key>;
+}
+
+#[derive(Debug)]
+pub struct FailedAllocationError {
+    reason: &'static str,
+}
+
+impl error::Error for FailedAllocationError {
+    fn description(&self) -> &str {
+        self.reason
+    }
+}
+
+impl fmt::Display for FailedAllocationError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.reason.fmt(f)
+    }
+}

components/hashglobe/src/shim.rs

@@ -0,0 +1,60 @@
+use std::marker::PhantomData;
+
+pub struct NonZeroPtr<T: 'static>(&'static T);
+
+impl<T: 'static> NonZeroPtr<T> {
+    pub unsafe fn new_unchecked(ptr: *mut T) -> Self {
+        NonZeroPtr(&*ptr)
+    }
+    pub fn as_ptr(&self) -> *mut T {
+        self.0 as *const T as *mut T
+    }
+}
+
+pub struct Unique<T: 'static> {
+    ptr: NonZeroPtr<T>,
+    _marker: PhantomData<T>,
+}
+
+impl<T: 'static> Unique<T> {
+    pub unsafe fn new_unchecked(ptr: *mut T) -> Self {
+        Unique {
+            ptr: NonZeroPtr::new_unchecked(ptr),
+            _marker: PhantomData,
+        }
+    }
+    pub fn as_ptr(&self) -> *mut T {
+        self.ptr.as_ptr()
+    }
+}
+
+unsafe impl<T: Send + 'static> Send for Unique<T> { }
+
+unsafe impl<T: Sync + 'static> Sync for Unique<T> { }
+
+pub struct Shared<T: 'static>  {
+    ptr: NonZeroPtr<T>,
+    _marker: PhantomData<T>,
+    // force it to be !Send/!Sync
+    _marker2: PhantomData<*const u8>,
+}
+
+impl<T: 'static> Shared<T> {
+    pub unsafe fn new_unchecked(ptr: *mut T) -> Self {
+        Shared {
+            ptr: NonZeroPtr::new_unchecked(ptr),
+            _marker: PhantomData,
+            _marker2: PhantomData,
+        }
+    }
+
+    pub unsafe fn as_mut(&self) -> &mut T {
+        &mut *self.ptr.as_ptr()
+    }
+}
+
+impl<'a, T> From<&'a mut T> for Shared<T> {
+    fn from(reference: &'a mut T) -> Self {
+        unsafe { Shared::new_unchecked(reference) }
+    }
+}

components/style/Cargo.toml

@@ -41,6 +41,7 @@ cssparser = "0.19.5"
 encoding = {version = "0.2", optional = true}
 euclid = "0.15"
 fnv = "1.0"
+hashglobe = { path = "../hashglobe" }
 heapsize = {version = "0.4", optional = true}
 heapsize_derive = {version = "0.1", optional = true}
 itertools = "0.5"

components/style/custom_properties.rs

@@ -8,13 +8,13 @@
 
 use Atom;
 use cssparser::{Delimiter, Parser, ParserInput, SourcePosition, Token, TokenSerializationType};
+use hash::{HashMap, HashSet};
 use parser::ParserContext;
 use properties::{CSSWideKeyword, DeclaredValue};
 use selectors::parser::SelectorParseError;
 use servo_arc::Arc;
 use std::ascii::AsciiExt;
 use std::borrow::{Borrow, Cow};
-use std::collections::{HashMap, HashSet};
 use std::fmt;
 use std::hash::Hash;
 use style_traits::{ToCss, StyleParseError, ParseError};

components/style/dom.rs

@@ -28,7 +28,7 @@ use servo_arc::{Arc, ArcBorrow};
 use shared_lock::Locked;
 use smallvec::VecLike;
 use std::fmt;
-#[cfg(feature = "gecko")] use std::collections::HashMap;
+#[cfg(feature = "gecko")] use hash::HashMap;
 use std::fmt::Debug;
 use std::hash::Hash;
 use std::ops::Deref;

components/style/gecko/wrapper.rs

@@ -66,6 +66,7 @@ use gecko_bindings::structs::nsChangeHint;
 use gecko_bindings::structs::nsIDocument_DocumentTheme as DocumentTheme;
 use gecko_bindings::structs::nsRestyleHint;
 use gecko_bindings::sugar::ownership::{HasArcFFI, HasSimpleFFI};
+use hash::HashMap;
 use logical_geometry::WritingMode;
 use media_queries::Device;
 use properties::{ComputedValues, parse_style_attribute};
@@ -83,7 +84,6 @@ use selectors::sink::Push;
 use servo_arc::{Arc, ArcBorrow, RawOffsetArc};
 use shared_lock::Locked;
 use std::cell::RefCell;
-use std::collections::HashMap;
 use std::fmt;
 use std::hash::{Hash, Hasher};
 use std::mem;
@@ -1361,7 +1361,7 @@ impl<'le> TElement for GeckoElement<'le> {
                                 after_change_style: &ComputedValues)
                                 -> bool {
         use gecko_bindings::structs::nsCSSPropertyID;
-        use std::collections::HashSet;
+        use hash::HashSet;
 
         debug_assert!(self.might_need_transitions_update(Some(before_change_style),
                                                          after_change_style),

components/style/hash.rs

@@ -0,0 +1,32 @@
+/* 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/. */
+
+//! Reexports of hashglobe types in Gecko mode, and stdlib hashmap shims in Servo mode
+//!
+//! Can go away when the stdlib gets fallible collections
+//! https://github.com/rust-lang/rfcs/pull/2116
+
+use fnv;
+
+#[cfg(feature = "gecko")]
+pub use hashglobe::hash_map::HashMap;
+#[cfg(feature = "gecko")]
+pub use hashglobe::hash_set::HashSet;
+
+
+#[cfg(feature = "servo")]
+pub use hashglobe::fake::{HashMap, HashSet};
+
+/// Appropriate reexports of hash_map types
+pub mod map {
+    #[cfg(feature = "gecko")]
+    pub use hashglobe::hash_map::{Entry, Iter};
+    #[cfg(feature = "servo")]
+    pub use std::collections::hash_map::{Entry, Iter};
+}
+
+/// Hash map that uses the FNV hasher
+pub type FnvHashMap<K, V> = HashMap<K, V, fnv::FnvBuildHasher>;
+/// Hash set that uses the FNV hasher
+pub type FnvHashSet<T> = HashSet<T, fnv::FnvBuildHasher>;

components/style/lib.rs

@@ -49,6 +49,7 @@ extern crate bitflags;
 extern crate euclid;
 extern crate fnv;
 #[cfg(feature = "gecko")] #[macro_use] pub mod gecko_string_cache;
+extern crate hashglobe;
 #[cfg(feature = "servo")] extern crate heapsize;
 #[cfg(feature = "servo")] #[macro_use] extern crate heapsize_derive;
 extern crate itertools;
@@ -112,6 +113,7 @@ pub mod font_face;
 pub mod font_metrics;
 #[cfg(feature = "gecko")] #[allow(unsafe_code)] pub mod gecko;
 #[cfg(feature = "gecko")] #[allow(unsafe_code)] pub mod gecko_bindings;
+pub mod hash;
 pub mod invalidation;
 #[allow(missing_docs)] // TODO.
 pub mod logical_geometry;

components/style/properties/helpers/animated_properties.mako.rs

@@ -31,7 +31,7 @@ use selectors::parser::SelectorParseError;
 use smallvec::SmallVec;
 use std::borrow::Cow;
 use std::cmp;
-#[cfg(feature = "gecko")] use fnv::FnvHashMap;
+#[cfg(feature = "gecko")] use hash::FnvHashMap;
 use style_traits::ParseError;
 use super::ComputedValues;
 #[cfg(feature = "gecko")]

components/style/properties/longhand/position.mako.rs

@@ -416,7 +416,7 @@ ${helpers.predefined_type("object-position",
         products="gecko"
         animation_value_type="discrete"
         boxed="True">
-    use std::collections::HashMap;
+    use hash::HashMap;
     use std::fmt;
     use std::ops::Range;
     use str::HTML_SPACE_CHARACTERS;

components/style/properties/properties.mako.rs

@@ -13,7 +13,7 @@
 #[cfg(feature = "servo")] use app_units::Au;
 use servo_arc::{Arc, UniqueArc};
 use std::borrow::Cow;
-use std::collections::HashSet;
+use hash::HashSet;
 use std::{fmt, mem, ops};
 #[cfg(feature = "gecko")] use std::ptr;
 

components/style/rule_tree/mod.rs

@@ -1007,7 +1007,7 @@ impl StrongRuleNode {
 
     unsafe fn assert_free_list_has_no_duplicates_or_null(&self) {
         assert!(cfg!(debug_assertions), "This is an expensive check!");
-        use std::collections::HashSet;
+        use hash::HashSet;
 
         let me = &*self.ptr();
         assert!(me.is_root());

components/style/selector_map.rs

@@ -9,6 +9,8 @@ use {Atom, LocalName};
 use applicable_declarations::ApplicableDeclarationBlock;
 use context::QuirksMode;
 use dom::TElement;
+use hash::{HashMap, HashSet};
+use hash::map as hash_map;
 use pdqsort::sort_by;
 use precomputed_hash::PrecomputedHash;
 use rule_tree::CascadeLevel;
@@ -16,8 +18,6 @@ use selector_parser::SelectorImpl;
 use selectors::matching::{matches_selector, MatchingContext, ElementSelectorFlags};
 use selectors::parser::{Component, Combinator, SelectorIter};
 use smallvec::{SmallVec, VecLike};
-use std::collections::{HashMap, HashSet};
-use std::collections::hash_map;
 use std::hash::{BuildHasherDefault, Hash, Hasher};
 use stylist::Rule;
 
@@ -93,7 +93,7 @@ pub trait SelectorMapEntry : Sized + Clone {
 /// TODO: Tune the initial capacity of the HashMap
 #[derive(Debug)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-pub struct SelectorMap<T> {
+pub struct SelectorMap<T: 'static> {
     /// A hash from an ID to rules which contain that ID selector.
     pub id_hash: MaybeCaseInsensitiveHashMap<Atom, SmallVec<[T; 1]>>,
     /// A hash from a class name to rules which contain that class selector.
@@ -111,7 +111,10 @@ fn sort_by_key<T, F: Fn(&T) -> K, K: Ord>(v: &mut [T], f: F) {
     sort_by(v, |a, b| f(a).cmp(&f(b)))
 }
 
-impl<T> SelectorMap<T> {
+// FIXME(Manishearth) the 'static bound can be removed when
+// our HashMap fork (hashglobe) is able to use NonZero,
+// or when stdlib gets fallible collections
+impl<T: 'static> SelectorMap<T> {
     /// Trivially constructs an empty `SelectorMap`.
     pub fn new() -> Self {
         SelectorMap {
@@ -461,9 +464,12 @@ fn find_push<Str: Eq + Hash, V, VL>(map: &mut PrecomputedHashMap<Str, VL>,
 /// Wrapper for PrecomputedHashMap that does ASCII-case-insensitive lookup in quirks mode.
 #[derive(Debug)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-pub struct MaybeCaseInsensitiveHashMap<K: PrecomputedHash + Hash + Eq, V>(PrecomputedHashMap<K, V>);
+pub struct MaybeCaseInsensitiveHashMap<K: PrecomputedHash + Hash + Eq, V: 'static>(PrecomputedHashMap<K, V>);
 
-impl<V> MaybeCaseInsensitiveHashMap<Atom, V> {
+// FIXME(Manishearth) the 'static bound can be removed when
+// our HashMap fork (hashglobe) is able to use NonZero,
+// or when stdlib gets fallible collections
+impl<V: 'static> MaybeCaseInsensitiveHashMap<Atom, V> {
     /// Empty map
     pub fn new() -> Self {
         MaybeCaseInsensitiveHashMap(PrecomputedHashMap::default())

servo-tidy.toml

@@ -15,6 +15,7 @@ lint-scripts = [
 rand = [
   "deque",
   "gaol",
+  "hashglobe", # only uses in tests
   "ipc-channel",
   "num-bigint",
   "parking_lot_core",
@@ -74,6 +75,7 @@ directories = [
   "./components/script/dom/bindings/codegen/parser",
   "./components/script/dom/bindings/codegen/ply",
   "./python/_virtualenv",
+  "./components/hashglobe/src",
   # Generated and upstream code combined with our own. Could use cleanup
   "./target",
   "./ports/cef",