Overhaul MallocSizeOf and related things.

This patch makes the MallocSizeOf stuff in Stylo work more like the HeapSizeOf
stuff already in Servo, except better. In particular, it adds deriving support
for MallocSizeOf, which will make it easier to improve coverage.

The patch does the following.

- Combines servo/components/style/stylesheets/memory.rs and the heapsize crate
  into a new crate, malloc_size_of.

- Forks the heapsize_derive crate, calling it malloc_size_of, so that
  MallocSizeOf can be derived.

- Both the new crates have MIT/Apache licenses, like heapsize, in case they are
  incorporated into heapsize in the future.

- Renames the methods within MallocSizeOf and the related traits so they are
  more concise.

- Removes MallocSizeOfWithGuard.

- Adds `derive(MallocSizeOf)` to a lot of types, in some cases replacing an
  equivalent or almost-equivalent hand-written implementation.

- Adds stuff so that Rc/Arc can be handled properly.

ports/geckolib/Cargo.toml

@@ -19,6 +19,7 @@ cssparser = "0.20.2"
 env_logger = {version = "0.4", default-features = false} # disable `regex` to reduce code size
 libc = "0.2"
 log = {version = "0.3.5", features = ["release_max_level_info"]}
+malloc_size_of = {path = "../../components/malloc_size_of"}
 nsstring_vendor = {path = "../../components/style/gecko_bindings/nsstring_vendor"}
 parking_lot = "0.4"
 selectors = {path = "../../components/selectors"}

ports/geckolib/glue.rs

@@ -5,6 +5,7 @@
 use cssparser::{Parser, ParserInput};
 use cssparser::ToCss as ParserToCss;
 use env_logger::LogBuilder;
+use malloc_size_of::MallocSizeOfOps;
 use selectors::Element;
 use selectors::matching::{MatchingContext, MatchingMode, matches_selector};
 use servo_arc::{Arc, ArcBorrow, RawOffsetArc};
@@ -52,6 +53,7 @@ use style::gecko_bindings::bindings::Gecko_ConstructFontFeatureValueSet;
 use style::gecko_bindings::bindings::Gecko_GetOrCreateFinalKeyframe;
 use style::gecko_bindings::bindings::Gecko_GetOrCreateInitialKeyframe;
 use style::gecko_bindings::bindings::Gecko_GetOrCreateKeyframeAtStart;
+use style::gecko_bindings::bindings::Gecko_HaveSeenPtr;
 use style::gecko_bindings::bindings::Gecko_NewNoneTransform;
 use style::gecko_bindings::bindings::RawGeckoAnimationPropertySegmentBorrowed;
 use style::gecko_bindings::bindings::RawGeckoCSSPropertyIDListBorrowed;
@@ -120,9 +122,8 @@ use style::shared_lock::{SharedRwLockReadGuard, StylesheetGuards, ToCssWithGuard
 use style::string_cache::Atom;
 use style::style_adjuster::StyleAdjuster;
 use style::stylesheets::{CssRule, CssRules, CssRuleType, CssRulesHelpers, DocumentRule};
-use style::stylesheets::{FontFeatureValuesRule, ImportRule, KeyframesRule, MallocEnclosingSizeOfFn};
-use style::stylesheets::{MallocSizeOfFn, MallocSizeOfWithGuard, MediaRule};
-use style::stylesheets::{NamespaceRule, Origin, OriginSet, PageRule, SizeOfState, StyleRule};
+use style::stylesheets::{FontFeatureValuesRule, ImportRule, KeyframesRule, MediaRule};
+use style::stylesheets::{NamespaceRule, Origin, OriginSet, PageRule, StyleRule};
 use style::stylesheets::{StylesheetContents, SupportsRule};
 use style::stylesheets::StylesheetLoader as StyleStylesheetLoader;
 use style::stylesheets::keyframes_rule::{Keyframe, KeyframeSelector, KeyframesStepValue};
@@ -778,15 +779,13 @@ pub extern "C" fn Servo_Element_ClearData(element: RawGeckoElementBorrowed) {
 pub extern "C" fn Servo_Element_SizeOfExcludingThisAndCVs(malloc_size_of: GeckoMallocSizeOf,
                                                           seen_ptrs: *mut SeenPtrs,
                                                           element: RawGeckoElementBorrowed) -> usize {
-    let malloc_size_of = MallocSizeOfFn(malloc_size_of.unwrap());
     let element = GeckoElement(element);
     let borrow = element.borrow_data();
     if let Some(data) = borrow {
-        let mut state = SizeOfState {
-            malloc_size_of: malloc_size_of,
-            seen_ptrs: seen_ptrs,
-        };
-        (*data).malloc_size_of_children_excluding_cvs(&mut state)
+        let have_seen_ptr = move |ptr| { unsafe { Gecko_HaveSeenPtr(seen_ptrs, ptr) } };
+        let mut ops = MallocSizeOfOps::new(malloc_size_of.unwrap(), None,
+                                           Some(Box::new(have_seen_ptr)));
+        (*data).size_of_excluding_cvs(&mut ops)
     } else {
         0
     }
@@ -1086,8 +1085,8 @@ pub extern "C" fn Servo_StyleSheet_SizeOfIncludingThis(
 ) -> usize {
     let global_style_data = &*GLOBAL_STYLE_DATA;
     let guard = global_style_data.shared_lock.read();
-    let malloc_size_of = MallocSizeOfFn(malloc_size_of.unwrap());
-    StylesheetContents::as_arc(&sheet).malloc_size_of_children(&guard, malloc_size_of)
+    let mut ops = MallocSizeOfOps::new(malloc_size_of.unwrap(), None, None);
+    StylesheetContents::as_arc(&sheet).size_of(&guard, &mut ops)
 }
 
 #[no_mangle]
@@ -3710,10 +3709,10 @@ pub extern "C" fn Servo_StyleSet_AddSizeOfExcludingThis(
     raw_data: RawServoStyleSetBorrowed
 ) {
     let data = PerDocumentStyleData::from_ffi(raw_data).borrow_mut();
-    let malloc_size_of = MallocSizeOfFn(malloc_size_of.unwrap());
-    let malloc_enclosing_size_of = MallocEnclosingSizeOfFn(malloc_enclosing_size_of.unwrap());
+    let mut ops = MallocSizeOfOps::new(malloc_size_of.unwrap(),
+                                       malloc_enclosing_size_of, None);
     let sizes = unsafe { sizes.as_mut() }.unwrap();
-    data.malloc_add_size_of_children(malloc_size_of, malloc_enclosing_size_of, sizes);
+    data.add_size_of_children(&mut ops, sizes);
 }
 
 #[no_mangle]

ports/geckolib/lib.rs

@@ -8,6 +8,7 @@ extern crate cssparser;
 extern crate env_logger;
 extern crate libc;
 #[macro_use] extern crate log;
+extern crate malloc_size_of;
 extern crate selectors;
 extern crate servo_arc;
 #[macro_use] extern crate style;