jscntxt.c

java script test programing source code

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sw=4 et tw=80:
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Communicator client code, released
 * March 31, 1998.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

/*
 * JS execution context.
 */
#include "jsstddef.h"
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include "jstypes.h"
#include "jsarena.h" /* Added by JSIFY */
#include "jsutil.h" /* Added by JSIFY */
#include "jsclist.h"
#include "jsprf.h"
#include "jsatom.h"
#include "jscntxt.h"
#include "jsconfig.h"
#include "jsdbgapi.h"
#include "jsexn.h"
#include "jsgc.h"
#include "jslock.h"
#include "jsnum.h"
#include "jsobj.h"
#include "jsopcode.h"
#include "jsscan.h"
#include "jsscope.h"
#include "jsscript.h"
#include "jsstr.h"

#ifdef JS_THREADSAFE

/*
 * Callback function to delete a JSThread info when the thread that owns it
 * is destroyed.
 */
void JS_DLL_CALLBACK
js_ThreadDestructorCB(void *ptr)
{
    JSThread *thread = (JSThread *)ptr;

    if (!thread)
        return;
    while (!JS_CLIST_IS_EMPTY(&thread->contextList)) {
        /* NB: use a temporary, as the macro evaluates its args many times. */
        JSCList *link = thread->contextList.next;

        JS_REMOVE_AND_INIT_LINK(link);
    }
    GSN_CACHE_CLEAR(&thread->gsnCache);
    free(thread);
}

/*
 * Get current thread-local JSThread info, creating one if it doesn't exist.
 * Each thread has a unique JSThread pointer.
 *
 * Since we are dealing with thread-local data, no lock is needed.
 *
 * Return a pointer to the thread local info, NULL if the system runs out
 * of memory, or it failed to set thread private data (neither case is very
 * likely; both are probably due to out-of-memory).  It is up to the caller
 * to report an error, if possible.
 */
JSThread *
js_GetCurrentThread(JSRuntime *rt)
{
    JSThread *thread;

    thread = (JSThread *)PR_GetThreadPrivate(rt->threadTPIndex);
    if (!thread) {
        thread = (JSThread *) calloc(1, sizeof(JSThread));
        if (!thread)
            return NULL;

        if (PR_FAILURE == PR_SetThreadPrivate(rt->threadTPIndex, thread)) {
            free(thread);
            return NULL;
        }

        JS_INIT_CLIST(&thread->contextList);
        thread->id = js_CurrentThreadId();

        /* js_SetContextThread initialize gcFreeLists as necessary. */
#ifdef DEBUG
        memset(thread->gcFreeLists, JS_FREE_PATTERN,
               sizeof(thread->gcFreeLists));
#endif
    }
    return thread;
}

/*
 * Sets current thread as owning thread of a context by assigning the
 * thread-private info to the context. If the current thread doesn't have
 * private JSThread info, create one.
 */
JSBool
js_SetContextThread(JSContext *cx)
{
    JSThread *thread = js_GetCurrentThread(cx->runtime);

    if (!thread) {
        JS_ReportOutOfMemory(cx);
        return JS_FALSE;
    }

    /*
     * Clear gcFreeLists on each transition from 0 to 1 context active on the
     * current thread. See bug 351602.
     */
    if (JS_CLIST_IS_EMPTY(&thread->contextList))
        memset(thread->gcFreeLists, 0, sizeof(thread->gcFreeLists));

    cx->thread = thread;
    JS_REMOVE_LINK(&cx->threadLinks);
    JS_APPEND_LINK(&cx->threadLinks, &thread->contextList);
    return JS_TRUE;
}

/* Remove the owning thread info of a context. */
void
js_ClearContextThread(JSContext *cx)
{
    JS_REMOVE_AND_INIT_LINK(&cx->threadLinks);
#ifdef DEBUG
    if (JS_CLIST_IS_EMPTY(&cx->thread->contextList)) {
        memset(cx->thread->gcFreeLists, JS_FREE_PATTERN,
               sizeof(cx->thread->gcFreeLists));
    }
#endif
    cx->thread = NULL;
}

#endif /* JS_THREADSAFE */

void
js_OnVersionChange(JSContext *cx)
{
#ifdef DEBUG
    JSVersion version = JSVERSION_NUMBER(cx);

    JS_ASSERT(version == JSVERSION_DEFAULT || version >= JSVERSION_ECMA_3);
#endif
}

void
js_SetVersion(JSContext *cx, JSVersion version)
{
    cx->version = version;
    js_OnVersionChange(cx);
}

JSContext *
js_NewContext(JSRuntime *rt, size_t stackChunkSize)
{
    JSContext *cx;
    JSBool ok, first;
    JSContextCallback cxCallback;

    cx = (JSContext *) malloc(sizeof *cx);
    if (!cx)
        return NULL;
    memset(cx, 0, sizeof *cx);

    cx->runtime = rt;
#if JS_STACK_GROWTH_DIRECTION > 0
    cx->stackLimit = (jsuword)-1;
#endif
#ifdef JS_THREADSAFE
    JS_INIT_CLIST(&cx->threadLinks);
    js_SetContextThread(cx);
#endif

    JS_LOCK_GC(rt);
    for (;;) {
        first = (rt->contextList.next == &rt->contextList);
        if (rt->state == JSRTS_UP) {
            JS_ASSERT(!first);
            break;
        }
        if (rt->state == JSRTS_DOWN) {
            JS_ASSERT(first);
            rt->state = JSRTS_LAUNCHING;
            break;
        }
        JS_WAIT_CONDVAR(rt->stateChange, JS_NO_TIMEOUT);
    }
    JS_APPEND_LINK(&cx->links, &rt->contextList);
    JS_UNLOCK_GC(rt);

    /*
     * First we do the infallible, every-time per-context initializations.
     * Should a later, fallible initialization (js_InitRegExpStatics, e.g.,
     * or the stuff under 'if (first)' below) fail, at least the version
     * and arena-pools will be valid and safe to use (say, from the last GC
     * done by js_DestroyContext).
     */
    cx->version = JSVERSION_DEFAULT;
    cx->jsop_eq = JSOP_EQ;
    cx->jsop_ne = JSOP_NE;
    JS_InitArenaPool(&cx->stackPool, "stack", stackChunkSize, sizeof(jsval));
    JS_InitArenaPool(&cx->tempPool, "temp", 1024, sizeof(jsdouble));

    if (!js_InitRegExpStatics(cx, &cx->regExpStatics)) {
        js_DestroyContext(cx, JSDCM_NEW_FAILED);
        return NULL;
    }

    /*
     * If cx is the first context on this runtime, initialize well-known atoms,
     * keywords, numbers, and strings.  If one of these steps should fail, the
     * runtime will be left in a partially initialized state, with zeroes and
     * nulls stored in the default-initialized remainder of the struct.  We'll
     * clean the runtime up under js_DestroyContext, because cx will be "last"
     * as well as "first".
     */
    if (first) {
#ifdef JS_THREADSAFE
        JS_BeginRequest(cx);
#endif
        /*
         * Both atomState and the scriptFilenameTable may be left over from a
         * previous episode of non-zero contexts alive in rt, so don't re-init
         * either table if it's not necessary.  Just repopulate atomState with
         * well-known internal atoms, and with the reserved identifiers added
         * by the scanner.
         */
        ok = (rt->atomState.liveAtoms == 0)
             ? js_InitAtomState(cx, &rt->atomState)
             : js_InitPinnedAtoms(cx, &rt->atomState);
        if (ok && !rt->scriptFilenameTable)
            ok = js_InitRuntimeScriptState(rt);
        if (ok)
            ok = js_InitRuntimeNumberState(cx);
        if (ok)
            ok = js_InitRuntimeStringState(cx);
#ifdef JS_THREADSAFE
        JS_EndRequest(cx);
#endif
        if (!ok) {
            js_DestroyContext(cx, JSDCM_NEW_FAILED);
            return NULL;
        }

        JS_LOCK_GC(rt);
        rt->state = JSRTS_UP;
        JS_NOTIFY_ALL_CONDVAR(rt->stateChange);
        JS_UNLOCK_GC(rt);
    }

    cxCallback = rt->cxCallback;
    if (cxCallback && !cxCallback(cx, JSCONTEXT_NEW)) {
        js_DestroyContext(cx, JSDCM_NEW_FAILED);
        return NULL;
    }
    return cx;
}

void
js_DestroyContext(JSContext *cx, JSDestroyContextMode mode)
{
    JSRuntime *rt;
    JSContextCallback cxCallback;
    JSBool last;
    JSArgumentFormatMap *map;
    JSLocalRootStack *lrs;
    JSLocalRootChunk *lrc;

    rt = cx->runtime;

    if (mode != JSDCM_NEW_FAILED) {
        cxCallback = rt->cxCallback;
        if (cxCallback) {
            /*
             * JSCONTEXT_DESTROY callback is not allowed to fail and must
             * return true.
             */
#ifdef DEBUG
            JSBool callbackStatus =
#endif
            cxCallback(cx, JSCONTEXT_DESTROY);
            JS_ASSERT(callbackStatus);
        }
    }

    /* Remove cx from context list first. */
    JS_LOCK_GC(rt);
    JS_ASSERT(rt->state == JSRTS_UP || rt->state == JSRTS_LAUNCHING);
    JS_REMOVE_LINK(&cx->links);
    last = (rt->contextList.next == &rt->contextList);
    if (last)
        rt->state = JSRTS_LANDING;
    JS_UNLOCK_GC(rt);

    if (last) {
#ifdef JS_THREADSAFE
        /*
         * If cx is not in a request already, begin one now so that we wait
         * for any racing GC started on a not-last context to finish, before
         * we plow ahead and unpin atoms.  Note that even though we begin a
         * request here if necessary, we end all requests on cx below before
         * forcing a final GC.  This lets any not-last context destruction
         * racing in another thread try to force or maybe run the GC, but by
         * that point, rt->state will not be JSRTS_UP, and that GC attempt
         * will return early.
         */
        if (cx->requestDepth == 0)
            JS_BeginRequest(cx);
#endif

        /* Unpin all pinned atoms before final GC. */
        js_UnpinPinnedAtoms(&rt->atomState);

        /* Unlock and clear GC things held by runtime pointers. */
        js_FinishRuntimeNumberState(cx);
        js_FinishRuntimeStringState(cx);

        /* Clear debugging state to remove GC roots. */
        JS_ClearAllTraps(cx);
        JS_ClearAllWatchPoints(cx);
    }

    /*
     * Remove more GC roots in regExpStatics, then collect garbage.
     * XXX anti-modularity alert: we rely on the call to js_RemoveRoot within
     * XXX this function call to wait for any racing GC to complete, in the
     * XXX case where JS_DestroyContext is called outside of a request on cx
     */
    js_FreeRegExpStatics(cx, &cx->regExpStatics);

#ifdef JS_THREADSAFE
    /*
     * Destroying a context implicitly calls JS_EndRequest().  Also, we must
     * end our request here in case we are "last" -- in that event, another
     * js_DestroyContext that was not last might be waiting in the GC for our
     * request to end.  We'll let it run below, just before we do the truly
     * final GC and then free atom state.
     *
     * At this point, cx must be inaccessible to other threads.  It's off the
     * rt->contextList, and it should not be reachable via any object private
     * data structure.
     */
    while (cx->requestDepth != 0)
        JS_EndRequest(cx);
#endif

    if (last) {
        js_GC(cx, GC_LAST_CONTEXT);

        /* Try to free atom state, now that no unrooted scripts survive. */
        if (rt->atomState.liveAtoms == 0)
            js_FreeAtomState(cx, &rt->atomState);

        /* Also free the script filename table if it exists and is empty. */
        if (rt->scriptFilenameTable && rt->scriptFilenameTable->nentries == 0)
            js_FinishRuntimeScriptState(rt);

        /*
         * Free the deflated string cache, but only after the last GC has
         * collected all unleaked strings.
         */
        js_FinishDeflatedStringCache(rt);

        /* Take the runtime down, now that it has no contexts or atoms. */
        JS_LOCK_GC(rt);
        rt->state = JSRTS_DOWN;
        JS_NOTIFY_ALL_CONDVAR(rt->stateChange);
        JS_UNLOCK_GC(rt);
    } else {
        if (mode == JSDCM_FORCE_GC)
            js_GC(cx, GC_NORMAL);
        else if (mode == JSDCM_MAYBE_GC)