When serialising JS objects, we keep track of any encountered object,
and serialize it only once. Any further serialisation instead stores an
ID referring to the original object (essentially an opaque pointer).
The trouble of course is to have a unique, persistent identifier for
such an object.
svn uses an ObjectIDCache, essentially a "JS Object -> ID" map (which
internally is essentially a "JS heap pointer -> ID" map).
JS, since ES15, includes a "Symbol" primitive type, which is a unique,
immutable identifier. They are also not iterable by for..in or
GetOwnPropertyName or related.
This means they can be used to store the tag directly on the object
(since it's impossible overwrite a user property).
Thanks to this, we can forgo ObjectIDCache in the serializers, and since
following D2897 it becomes unused, we can delete it, along with the
Finalization code it used.
Part of SM52 migration, stage: SM45-compatible changes.
Patch by: Itms
Tested By: Freagarach
Refs #4893
Differential Revision: https://code.wildfiregames.com/D3085
This was SVN commit r24167.
This also adds some validation to ensure the correct order of JS_Init,
JS_NewRuntime, JS_DestroyRuntime and JS_ShutDown calls.
Refs #3708
This was SVN commit r18584.
This upgrade also introduces exact stack rooting (see to the wiki:
JSRootingGuide) and fixes problems with moving GC. This allows us to
enable generational garbage collection (GGC).
Measurements a few months ago have shown a performance improvement of a
non-visual replay of around 13.5%. This probably varies quite a bit, but
it should be somewhere between 5-20%. Memory usage has also been
improved. Check the forum thread for details.
Thanks to everyone from the team who helped with this directly or
indirectly (review, finding and fixing issues, the required C++11
upgrade, the new autobuilder etc.)! Also thanks to the SpiderMonkey
developers who helped on the #jsapi channel or elsewhere!
Fixes#2462, #2415, #2428, #2684, #1374
Refs #2973, #2669
This was SVN commit r16214.
The runtime is becoming more and more important in the JSAPI. As a
result, we also have more functionality on the runtime level and having
the whole ScriptRuntime class hidden in ScriptInterface.cpp doesn't make
sense anymore. ScriptInterface.cpp also has become quite a large file
and pulling out the runtime part makes it a bit smaller.
Refs #2462
This was SVN commit r15961.
