Currently static atoms are stored on the heap, but their char buffers are
stored in read-only static memory.
This patch changes the representation of nsStaticAtom (thus making it a
non-trivial subclass of nsAtom). Instead of a pointer to the string, it now has
an mStringOffset field which is a 32-bit offset to the string. (This requires
placement of the string and the atom within the same object so that the offset
is known to be small. The docs and macros in nsStaticAtom.h handle that.)
Static and dynamic atoms now store their chars in different ways: nsStaticAtom
stores them inline, nsDynamicAtom has a pointer to separate storage. So
`mString` and GetStringBuffer() move from nsAtom to nsDynamicAtom.
The change to static atoms means they can be made constexpr and stored in
read-only memory instead of on the heap. On 64-bit this reduces the per-process
overhead by 16 bytes; on 32-bit the saving is 12 bytes. (Further reductions
will be possible in follow-up patches.)
The increased use of constexpr required multiple workarounds for MSVC.
- Multiple uses of MOZ_{PUSH,POP}_DISABLE_INTEGRAL_CONSTANT_OVERFLOW_WARNING to
disable warnings about (well-defined!) overflow of unsigned integer
arithmetic.
- The use of -Zc:externConstexpr on all files defining static atoms, to make
MSVC follow the C++ standard(!) and let constexpr variables have external
linkage.
- The use of -constexpr:steps300000 to increase the number of operations
allowed in a constexpr value, in order to handle gGkAtoms, which requires
hashing ~2,500 atom strings.
The patch also changes how HTML5 atoms are handled. They are now treated as
dynamic atoms, i.e. we have "dynamic normal" atoms and "dynamic HTML5 atoms",
and "dynamic atoms" covers both cases, and both are represented via
nsDynamicAtom. The main difference between the two kinds is that dynamic HTML5
atoms still aren't allowed to be used in various operations, most notably
AddRef()/Release(). All this also required moving nsDynamicAtom into the header
file.
There is a slight performance cost to all these changes: now that nsStaticAtom
and nsDynamicAtom store their chars in different ways, a conditional branch is
required in the following functions: Equals(), GetUTF16String(),
WeakAtom::as_slice().
Finally, in about:memory the "explicit/atoms/static/atom-objects" value is no
longer needed, because that memory is static instead of heap-allocated.
MozReview-Commit-ID: 4AxPv05ngZy
It seems silly to have a tiny utils class with a single function in its own
module. This patch moves it into nsStaticAtom.h/nsAtomTable.cpp. It also
renames nsAtomListUtils as nsStaticAtomUtils. Finally, it uses templates to
remove the need for the `aCount` parameter at callsites.
MozReview-Commit-ID: DvJVoZFv89c
Because (a) that name better indicates that it's a pointer to a pointer, and
(b) because nsStaticAtom::mString is going to be renamed as mAtom in bug
1411469.
MozReview-Commit-ID: D5tuNOstMgr
This patch was generated automatically by the "modeline.py" script, available
here: https://github.com/amccreight/moz-source-tools/blob/master/modeline.py
For every file that is modified in this patch, the changes are as follows:
(1) The patch changes the file to use the exact C++ mode lines from the
Mozilla coding style guide, available here:
https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Coding_Style#Mode_Line
(2) The patch deletes any blank lines between the mode line & the MPL
boilerplate comment.
(3) If the file previously had the mode lines and MPL boilerplate in a
single contiguous C++ comment, then the patch splits them into
separate C++ comments, to match the boilerplate in the coding style.
MozReview-Commit-ID: EuRsDue63tK
There are four things that must be provided for every static atom, two of which
have a macro:
- the atom pointer declaration (no macro);
- the atom pointer definition (no macro);
- the atom char buffer (NS_STATIC_ATOM_BUFFER);
- the StaticAtomSetup struct (NS_STATIC_ATOM_SETUP).
This patch introduces new macros for the first two things: NS_STATIC_ATOM_DECL
and NS_STATIC_ATOM_DEFN, and changes the arguments of the existing two macros
to make them easier to use (e.g. all the '##' concatenation now happens within
the macros).
One consequence of the change is that all static atoms must be within a class,
so the patch adds a couple of classes where necessary (DefaultAtoms, TSAtoms).
The patch also adds a big comment explaining how the macros are used, and what
their expansion looks like. This makes it a lot easier to understand how static
atoms work. Correspondingly, the patch removes some small comments scattered
around the macro use points.
MozReview-Commit-ID: wpRyrEOTHE
Because it's the type we use to set up static atoms at startup, not the static
atom itself.
The patch accordingly renames some parameters, variables, and NS_STATIC_ATOM,
for consistency.
MozReview-Commit-ID: 1a0KvhYNNw2
(Path is actually r=froydnj.)
Bug 1400459 devirtualized nsIAtom so that it is no longer a subclass of
nsISupports. This means that nsAtom is now a better name for it than nsIAtom.
MozReview-Commit-ID: 91U22X2NydP
This patch merges nsAtom into nsIAtom. For the moment, both names can be used
interchangeably due to a typedef. The patch also devirtualizes nsIAtom, by
making it not inherit from nsISupports, removing NS_DECL_NSIATOM, and dropping
the use of NS_IMETHOD_. It also removes nsIAtom's IIDs.
These changes trigger knock-on changes throughout the codebase, changing the
types of lots of things as follows.
- nsCOMPtr<nsIAtom> --> RefPtr<nsIAtom>
- nsCOMArray<nsIAtom> --> nsTArray<RefPtr<nsIAtom>>
- Count() --> Length()
- ObjectAt() --> ElementAt()
- AppendObject() --> AppendElement()
- RemoveObjectAt() --> RemoveElementAt()
- ns*Hashtable<nsISupportsHashKey, ...> -->
ns*Hashtable<nsRefPtrHashKey<nsIAtom>, ...>
- nsInterfaceHashtable<T, nsIAtom> --> nsRefPtrHashtable<T, nsIAtom>
- This requires adding a Get() method to nsRefPtrHashtable that it lacks but
nsInterfaceHashtable has.
- nsCOMPtr<nsIMutableArray> --> nsTArray<RefPtr<nsIAtom>>
- nsArrayBase::Create() --> nsTArray()
- GetLength() --> Length()
- do_QueryElementAt() --> operator[]
The patch also has some changes to Rust code that manipulates nsIAtom.
MozReview-Commit-ID: DykOl8aEnUJ
In this patch, we implement nsIDOMWindowUtils::GetUnanimatedComputedStyle
which returns computed value of given CSS property without animation rule. This
method is used from the DevTools animation inspector to fill in keyframe values
when the property value is null (indicating that the underlying/base value is
being used).
In order to implement this, we extend nsComputedDOMStyle constructor to fetch
the computed style minus animation style (i.e. the base style). This is somewhat
complicated by the fact that for discrete animation.
StyleAnimationValue::ExtractComputedValue may return ‘unset’, ‘initial’ or
‘inherit’. For example, if the author uses the 'unset' 'initial' or 'inherit'
keyword for a discrete property (e.g. 'align-content’), ExtractComputedValue
returns the keywords as-is. Furthermore, if the user does not set any specific
keyword, ExtractComputedValue returns ‘unset’. We use this new
nsComputedDOMStyle mechanism to resolve these keywords into a valid keyword for
computed style in the same way as other properties (e.g. ‘opacity’).
MozReview-Commit-ID: HffJ9SCDf2k
The idea is to be able to call the right function during style resolution time
without doing a linear walk via nsCSSAnonBoxes::IsNonInheritingAnonBox.
MozReview-Commit-ID: JKt33GggTjz
In order to convert CSSPseudoElementType into its underlying type easier,
we define CSSPseudoElementTypeBase. However, keep using uint8_t directly for
forward declarations.
selectors containing unrecognized pseudo-classes and pseudo-elements (bug
145968). Fix some CSS rules in quirk.css and xul.css that were bogus (no
bug). Patch in bug 62843. r+sr=dbaron
