src/third_party/mozjs-45/js/src/vm/RegExpStatics.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sts=4 et sw=4 tw=99:
 * 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/. */

#include "vm/RegExpStatics.h"

#include "vm/RegExpStaticsObject.h"

#include "vm/NativeObject-inl.h"

using namespace js;

/*
 * RegExpStatics allocates memory -- in order to keep the statics stored
 * per-global and not leak, we create a js::Class to wrap the C++ instance and
 * provide an appropriate finalizer. We lazily create and store an instance of
 * that js::Class in a global reserved slot.
 */

static void
resc_finalize(FreeOp* fop, JSObject* obj)
{
    RegExpStatics* res = static_cast<RegExpStatics*>(obj->as<RegExpStaticsObject>().getPrivate());
    fop->delete_(res);
}

static void
resc_trace(JSTracer* trc, JSObject* obj)
{
    void* pdata = obj->as<RegExpStaticsObject>().getPrivate();
    MOZ_ASSERT(pdata);
    RegExpStatics* res = static_cast<RegExpStatics*>(pdata);
    res->mark(trc);
}

const Class RegExpStaticsObject::class_ = {
    "RegExpStatics",
    JSCLASS_HAS_PRIVATE,
    nullptr, /* addProperty */
    nullptr, /* delProperty */
    nullptr, /* getProperty */
    nullptr, /* setProperty */
    nullptr, /* enumerate */
    nullptr, /* resolve */
    nullptr, /* mayResolve */
    resc_finalize,
    nullptr, /* call */
    nullptr, /* hasInstance */
    nullptr, /* construct */
    resc_trace
};

RegExpStaticsObject*
RegExpStatics::create(ExclusiveContext* cx, Handle<GlobalObject*> parent)
{
    RegExpStaticsObject* obj = NewObjectWithGivenProto<RegExpStaticsObject>(cx, nullptr);
    if (!obj)
        return nullptr;
    RegExpStatics* res = cx->new_<RegExpStatics>();
    if (!res)
        return nullptr;
    obj->setPrivate(static_cast<void*>(res));
    return obj;
}

void
RegExpStatics::markFlagsSet(JSContext* cx)
{
    // Flags set on the RegExp function get propagated to constructed RegExp
    // objects, which interferes with optimizations that inline RegExp cloning
    // or avoid cloning entirely. Scripts making this assumption listen to
    // type changes on RegExp.prototype, so mark a state change to trigger
    // recompilation of all such code (when recompiling, a stub call will
    // always be performed).
    MOZ_ASSERT_IF(cx->global()->hasRegExpStatics(), this == cx->global()->getRegExpStatics(cx));

    MarkObjectGroupFlags(cx, cx->global(), OBJECT_FLAG_REGEXP_FLAGS_SET);
}

bool
RegExpStatics::executeLazy(JSContext* cx)
{
    if (!pendingLazyEvaluation)
        return true;

    MOZ_ASSERT(lazySource);
    MOZ_ASSERT(matchesInput);
    MOZ_ASSERT(lazyIndex != size_t(-1));

    /* Retrieve or create the RegExpShared in this compartment. */
    RegExpGuard g(cx);
    if (!cx->compartment()->regExps.get(cx, lazySource, lazyFlags, &g))
        return false;

    /*
     * It is not necessary to call aboutToWrite(): evaluation of
     * implicit copies is safe.
     */

    /* Execute the full regular expression. */
    RootedLinearString input(cx, matchesInput);
    RegExpRunStatus status = g->execute(cx, input, lazyIndex, &this->matches);
    if (status == RegExpRunStatus_Error)
        return false;

    /*
     * RegExpStatics are only updated on successful (matching) execution.
     * Re-running the same expression must therefore produce a matching result.
     */
    MOZ_ASSERT(status == RegExpRunStatus_Success);

    /* Unset lazy state and remove rooted values that now have no use. */
    pendingLazyEvaluation = false;
    lazySource = nullptr;
    lazyIndex = size_t(-1);

    return true;
}