C++ JSContext::names方法代码示例

JSAtom*
FrameIterator::functionDisplayAtom() const
{
    MOZ_ASSERT(!done());

    JSContext* cx = activation_->cx();

    if (missingFrameMessage_) {
        const char* msg = "asm.js/wasm frames may be missing; enable the profiler before running "
                          "to see all frames";
        JSAtom* atom = Atomize(cx, msg, strlen(msg));
        if (!atom) {
            cx->clearPendingException();
            return cx->names().empty;
        }

        return atom;
    }

    MOZ_ASSERT(codeRange_);

    JSAtom* atom = code_->getFuncDefAtom(cx, codeRange_->funcDefIndex());
    if (!atom) {
        cx->clearPendingException();
        return cx->names().empty;
    }

    return atom;
}

    bool report(Census &census, MutableHandleValue report) {
        JSContext *cx = census.cx;

        RootedObject obj(cx, NewBuiltinClassInstance(cx, &JSObject::class_));
        if (!obj)
            return false;

        RootedValue objectsReport(cx);
        if (!objects.report(census, &objectsReport) ||
            !JSObject::defineProperty(cx, obj, cx->names().objects, objectsReport))
            return false;

        RootedValue scriptsReport(cx);
        if (!scripts.report(census, &scriptsReport) ||
            !JSObject::defineProperty(cx, obj, cx->names().scripts, scriptsReport))
            return false;

        RootedValue stringsReport(cx);
        if (!strings.report(census, &stringsReport) ||
            !JSObject::defineProperty(cx, obj, cx->names().strings, stringsReport))
            return false;

        RootedValue otherReport(cx);
        if (!other.report(census, &otherReport) ||
            !JSObject::defineProperty(cx, obj, cx->names().other,   otherReport))
            return false;

        report.setObject(*obj);
        return true;
    }

UnrootedFlatString
StringBuffer::finishString()
{
    JSContext *cx = context();
    if (cb.empty())
        return UnrootedFlatString(cx->names().empty);

    size_t length = cb.length();
    if (!JSString::validateLength(cx, length))
        return UnrootedFlatString();

    JS_STATIC_ASSERT(JSShortString::MAX_SHORT_LENGTH < CharBuffer::InlineLength);
    if (JSShortString::lengthFits(length))
        return NewShortString<CanGC>(cx, TwoByteChars(cb.begin(), length));

    if (!cb.append('\0'))
        return UnrootedFlatString();

    jschar *buf = extractWellSized();
    if (!buf)
        return UnrootedFlatString();

    JSFlatString *str = js_NewString<CanGC>(cx, buf, length);
    if (!str)
        js_free(buf);
    return str;
}

/*
 * Since memory has been exhausted, avoid the normal error-handling path which
 * allocates an error object, report and callstack. If code is running, simply
 * throw the static atom "out of memory". If code is not running, call the
 * error reporter directly.
 *
 * Furthermore, callers of ReportOutOfMemory (viz., malloc) assume a GC does
 * not occur, so GC must be avoided or suppressed.
 */
void
js::ReportOutOfMemory(ExclusiveContext* cxArg)
{
#ifdef JS_MORE_DETERMINISTIC
    /*
     * OOMs are non-deterministic, especially across different execution modes
     * (e.g. interpreter vs JIT). In more-deterministic builds, print to stderr
     * so that the fuzzers can detect this.
     */
    fprintf(stderr, "ReportOutOfMemory called\n");
#endif

    if (!cxArg->isJSContext())
        return cxArg->addPendingOutOfMemory();

    JSContext* cx = cxArg->asJSContext();
    cx->runtime()->hadOutOfMemory = true;
    AutoSuppressGC suppressGC(cx);

    /* Report the oom. */
    if (JS::OutOfMemoryCallback oomCallback = cx->runtime()->oomCallback)
        oomCallback(cx, cx->runtime()->oomCallbackData);

    cx->setPendingException(StringValue(cx->names().outOfMemory));
}

/*
 * Since memory has been exhausted, avoid the normal error-handling path which
 * allocates an error object, report and callstack. If code is running, simply
 * throw the static atom "out of memory". If code is not running, call the
 * error reporter directly.
 *
 * Furthermore, callers of js_ReportOutOfMemory (viz., malloc) assume a GC does
 * not occur, so GC must be avoided or suppressed.
 */
void
js_ReportOutOfMemory(ThreadSafeContext *cxArg)
{
    if (!cxArg->isJSContext())
        return;
    JSContext *cx = cxArg->asJSContext();

    cx->runtime()->hadOutOfMemory = true;

    if (JS_IsRunning(cx)) {
        cx->setPendingException(StringValue(cx->names().outOfMemory));
        return;
    }

    /* Get the message for this error, but we don't expand any arguments. */
    const JSErrorFormatString *efs =
        js_GetLocalizedErrorMessage(cx, NULL, NULL, JSMSG_OUT_OF_MEMORY);
    const char *msg = efs ? efs->format : "Out of memory";

    /* Fill out the report, but don't do anything that requires allocation. */
    JSErrorReport report;
    PodZero(&report);
    report.flags = JSREPORT_ERROR;
    report.errorNumber = JSMSG_OUT_OF_MEMORY;
    PopulateReportBlame(cx, &report);

    /* Report the error. */
    if (JSErrorReporter onError = cx->errorReporter) {
        AutoSuppressGC suppressGC(cx);
        onError(cx, msg, &report);
    }
}

/*
 * Since memory has been exhausted, avoid the normal error-handling path which
 * allocates an error object, report and callstack. If code is running, simply
 * throw the static atom "out of memory". If code is not running, call the
 * error reporter directly.
 *
 * Furthermore, callers of js_ReportOutOfMemory (viz., malloc) assume a GC does
 * not occur, so GC must be avoided or suppressed.
 */
void
js_ReportOutOfMemory(ThreadSafeContext *cxArg)
{
#ifdef JS_MORE_DETERMINISTIC
    /*
     * OOMs are non-deterministic, especially across different execution modes
     * (e.g. interpreter vs JIT). In more-deterministic builds, print to stderr
     * so that the fuzzers can detect this.
     */
    fprintf(stderr, "js_ReportOutOfMemory called\n");
#endif

    if (cxArg->isForkJoinSlice()) {
        cxArg->asForkJoinSlice()->setPendingAbortFatal(ParallelBailoutOutOfMemory);
        return;
    }

    if (!cxArg->isJSContext())
        return;
    JSContext *cx = cxArg->asJSContext();

    cx->runtime()->hadOutOfMemory = true;

    if (JS_IsRunning(cx)) {
        cx->setPendingException(StringValue(cx->names().outOfMemory));
        return;
    }

    /* Get the message for this error, but we don't expand any arguments. */
    const JSErrorFormatString *efs =
        js_GetLocalizedErrorMessage(cx, nullptr, nullptr, JSMSG_OUT_OF_MEMORY);
    const char *msg = efs ? efs->format : "Out of memory";

    /* Fill out the report, but don't do anything that requires allocation. */
    JSErrorReport report;
    PodZero(&report);
    report.flags = JSREPORT_ERROR;
    report.errorNumber = JSMSG_OUT_OF_MEMORY;
    PopulateReportBlame(cx, &report);

    /* Report the error. */
    if (JSErrorReporter onError = cx->errorReporter) {
        AutoSuppressGC suppressGC(cx);
        onError(cx, msg, &report);
    }

    /*
     * We would like to enforce the invariant that any exception reported
     * during an OOM situation does not require wrapping. Besides avoiding
     * allocation when memory is low, this reduces the number of places where
     * we might need to GC.
     *
     * When JS code is running, we set the pending exception to an atom, which
     * does not need wrapping. If no JS code is running, no exception should be
     * set at all.
     */
    JS_ASSERT(!cx->isExceptionPending());
}

JSAtom *
StringBuffer::finishAtom()
{
    JSContext *cx = context();

    size_t length = cb.length();
    if (length == 0)
        return cx->names().empty;

    JSAtom *atom = AtomizeChars(cx, cb.begin(), length);
    cb.clear();
    return atom;
}

UnrootedAtom
StringBuffer::finishAtom()
{
    AssertCanGC();
    JSContext *cx = context();

    size_t length = cb.length();
    if (length == 0)
        return UnrootedAtom(cx->names().empty);

    UnrootedAtom atom = AtomizeChars<CanGC>(cx, cb.begin(), length);
    cb.clear();
    return atom;
}

static bool
MaybeCheckEvalFreeVariables(ExclusiveContext *cxArg, HandleScript evalCaller, HandleObject scopeChain,
                            Parser<FullParseHandler> &parser,
                            ParseContext<FullParseHandler> &pc)
{
    if (!evalCaller || !evalCaller->functionOrCallerFunction())
        return true;

    // Eval scripts are only compiled on the main thread.
    JSContext *cx = cxArg->asJSContext();

    // Watch for uses of 'arguments' within the evaluated script, both as
    // free variables and as variables redeclared with 'var'.
    RootedFunction fun(cx, evalCaller->functionOrCallerFunction());
    HandlePropertyName arguments = cx->names().arguments;
    for (AtomDefnRange r = pc.lexdeps->all(); !r.empty(); r.popFront()) {
        if (r.front().key() == arguments) {
            if (!CheckArgumentsWithinEval(cx, parser, fun))
                return false;
        }
    }
    for (AtomDefnListMap::Range r = pc.decls().all(); !r.empty(); r.popFront()) {
        if (r.front().key() == arguments) {
            if (!CheckArgumentsWithinEval(cx, parser, fun))
                return false;
        }
    }

    // If the eval'ed script contains any debugger statement, force construction
    // of arguments objects for the caller script and any other scripts it is
    // transitively nested inside. The debugger can access any variable on the
    // scope chain.
    if (pc.sc->hasDebuggerStatement()) {
        RootedObject scope(cx, scopeChain);
        while (scope->is<ScopeObject>() || scope->is<DebugScopeObject>()) {
            if (scope->is<CallObject>() && !scope->as<CallObject>().isForEval()) {
                RootedScript script(cx, scope->as<CallObject>().callee().getOrCreateScript(cx));
                if (!script)
                    return false;
                if (script->argumentsHasVarBinding()) {
                    if (!JSScript::argumentsOptimizationFailed(cx, script))
                        return false;
                }
            }
            scope = scope->enclosingScope();
        }
    }

    return true;
}

/*
 * Since memory has been exhausted, avoid the normal error-handling path which
 * allocates an error object, report and callstack. If code is running, simply
 * throw the static atom "out of memory". If code is not running, call the
 * error reporter directly.
 *
 * Furthermore, callers of js_ReportOutOfMemory (viz., malloc) assume a GC does
 * not occur, so GC must be avoided or suppressed.
 */
void
js_ReportOutOfMemory(ThreadSafeContext *cxArg)
{
    if (!cxArg->isJSContext())
        return;
    JSContext *cx = cxArg->asJSContext();

    cx->runtime()->hadOutOfMemory = true;

    if (JS_IsRunning(cx)) {
        cx->setPendingException(StringValue(cx->names().outOfMemory));
        return;
    }

    /* Get the message for this error, but we don't expand any arguments. */
    const JSErrorFormatString *efs =
        js_GetLocalizedErrorMessage(cx, NULL, NULL, JSMSG_OUT_OF_MEMORY);
    const char *msg = efs ? efs->format : "Out of memory";

    /* Fill out the report, but don't do anything that requires allocation. */
    JSErrorReport report;
    PodZero(&report);
    report.flags = JSREPORT_ERROR;
    report.errorNumber = JSMSG_OUT_OF_MEMORY;
    PopulateReportBlame(cx, &report);

    /* Report the error. */
    if (JSErrorReporter onError = cx->errorReporter) {
        AutoSuppressGC suppressGC(cx);
        onError(cx, msg, &report);
    }

    /*
     * We would like to enforce the invariant that any exception reported
     * during an OOM situation does not require wrapping. Besides avoiding
     * allocation when memory is low, this reduces the number of places where
     * we might need to GC.
     *
     * When JS code is running, we set the pending exception to an atom, which
     * does not need wrapping. If no JS code is running, no exception should be
     * set at all.
     */
    JS_ASSERT(!cx->isExceptionPending());
}