jsscript.c

来自「一个基于alice开发的机器人」· C语言 代码 · 共 1,288 行 · 第 1/3 页

            continue;
        nsrcnotes = PTRDIFF(sn, notes, jssrcnote);
        nsrcnotes++;            /* room for the terminator */

        /* Count the trynotes. */
        if (script->trynotes) {
            while (script->trynotes[ntrynotes].catchStart)
                ntrynotes++;
            ntrynotes++;        /* room for the end marker */
        }
    }

    if (!JS_XDRUint32(xdr, &length))
        return JS_FALSE;
    if (magic >= JSXDR_MAGIC_SCRIPT_2) {
        if (!JS_XDRUint32(xdr, &prologLength))
            return JS_FALSE;
        if (!JS_XDRUint32(xdr, &version))
            return JS_FALSE;

        /* To fuse allocations, we need srcnote and trynote counts early. */
        if (magic >= JSXDR_MAGIC_SCRIPT_4) {
            if (!JS_XDRUint32(xdr, &nsrcnotes))
                return JS_FALSE;
            if (!JS_XDRUint32(xdr, &ntrynotes))
                return JS_FALSE;
        }
    }

    if (xdr->mode == JSXDR_DECODE) {
        script = js_NewScript(cx, length, nsrcnotes, ntrynotes);
        if (!script)
            return JS_FALSE;
        if (magic >= JSXDR_MAGIC_SCRIPT_2) {
            script->main += prologLength;
            script->version = (JSVersion) version;

            /* If we know nsrcnotes, we allocated space for notes in script. */
            if (magic >= JSXDR_MAGIC_SCRIPT_4)
                notes = SCRIPT_NOTES(script);
        }
        *scriptp = script;
    }

    /*
     * Control hereafter must goto error on failure, in order for the DECODE
     * case to destroy script and conditionally free notes, which if non-null
     * in the (DECODE and version < _4) case must point at a temporary vector
     * allocated just below.
     */
    if (!JS_XDRBytes(xdr, (char *)script->code, length * sizeof(jsbytecode)) ||
        !XDRAtomMap(xdr, &script->atomMap)) {
        goto error;
    }

    if (magic < JSXDR_MAGIC_SCRIPT_4) {
        if (!JS_XDRUint32(xdr, &nsrcnotes))
            goto error;
        if (xdr->mode == JSXDR_DECODE) {
            notes = (jssrcnote *) JS_malloc(cx, nsrcnotes * sizeof(jssrcnote));
            if (!notes)
                goto error;
        }
    }

    if (!JS_XDRBytes(xdr, (char *)notes, nsrcnotes * sizeof(jssrcnote)) ||
        !JS_XDRCStringOrNull(xdr, (char **)&script->filename) ||
        !JS_XDRUint32(xdr, &lineno) ||
        !JS_XDRUint32(xdr, &depth) ||
        (magic < JSXDR_MAGIC_SCRIPT_4 && !JS_XDRUint32(xdr, &ntrynotes))) {
        goto error;
    }

    /* Script principals transcoding support comes with versions >= _3. */
    if (magic >= JSXDR_MAGIC_SCRIPT_3) {
        JSPrincipals *principals;
        uint32 encodeable;

        if (xdr->mode == JSXDR_ENCODE) {
            principals = script->principals;
            encodeable = (cx->runtime->principalsTranscoder != NULL);
            if (!JS_XDRUint32(xdr, &encodeable))
                goto error;
            if (encodeable &&
                !cx->runtime->principalsTranscoder(xdr, &principals)) {
                goto error;
            }
        } else {
            if (!JS_XDRUint32(xdr, &encodeable))
                goto error;
            if (encodeable) {
                if (!cx->runtime->principalsTranscoder) {
                    JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL,
                                         JSMSG_CANT_DECODE_PRINCIPALS);
                    goto error;
                }
                if (!cx->runtime->principalsTranscoder(xdr, &principals))
                    goto error;
                script->principals = principals;
            }
        }
    }

    if (xdr->mode == JSXDR_DECODE) {
        const char *filename = script->filename;
        if (filename) {
            filename = js_SaveScriptFilename(cx, filename);
            if (!filename)
                goto error;
            JS_free(cx, (void *) script->filename);
            script->filename = filename;
            filenameWasSaved = JS_TRUE;
        }
        script->lineno = (uintN)lineno;
        script->depth = (uintN)depth;

        if (magic < JSXDR_MAGIC_SCRIPT_4) {
            /*
             * Argh, we have to reallocate script, copy notes into the extra
             * space after the bytecodes, and free the temporary notes vector.
             * First, add enough slop to nsrcnotes so we can align the address
             * after the srcnotes of the first trynote.
             */
            uint32 osrcnotes = nsrcnotes;

            if (ntrynotes)
                nsrcnotes += JSTRYNOTE_ALIGNMASK;
            newscript = (JSScript *) JS_realloc(cx, script,
                                                sizeof(JSScript) +
                                                length * sizeof(jsbytecode) +
                                                nsrcnotes * sizeof(jssrcnote) +
                                                ntrynotes * sizeof(JSTryNote));
            if (!newscript)
                goto error;

            *scriptp = script = newscript;
            script->code = (jsbytecode *)(script + 1);
            script->main = script->code + prologLength;
            memcpy(script->code + length, notes, osrcnotes * sizeof(jssrcnote));
            JS_free(cx, (void *) notes);
            notes = NULL;
            if (ntrynotes) {
                script->trynotes = (JSTryNote *)
                                   ((jsword)(SCRIPT_NOTES(script) + nsrcnotes) &
                                    ~(jsword)JSTRYNOTE_ALIGNMASK);
            }
        }
    }

    while (ntrynotes) {
        JSTryNote *tn = &script->trynotes[--ntrynotes];
        uint32 start = (uint32) tn->start,
               catchLength = (uint32) tn->length,
               catchStart = (uint32) tn->catchStart;

        if (!JS_XDRUint32(xdr, &start) ||
            !JS_XDRUint32(xdr, &catchLength) ||
            !JS_XDRUint32(xdr, &catchStart)) {
            goto error;
        }
        tn->start = (ptrdiff_t) start;
        tn->length = (ptrdiff_t) catchLength;
        tn->catchStart = (ptrdiff_t) catchStart;
    }
    return JS_TRUE;

  error:
    if (xdr->mode == JSXDR_DECODE) {
        if (script->filename && !filenameWasSaved) {
            JS_free(cx, (void *) script->filename);
            script->filename = NULL;
        }
        if (notes && magic < JSXDR_MAGIC_SCRIPT_4)
            JS_free(cx, (void *) notes);
        js_DestroyScript(cx, script);
        *scriptp = NULL;
    }
    return JS_FALSE;
}

#if JS_HAS_XDR_FREEZE_THAW
/*
 * These cannot be exposed to web content, and chrome does not need them, so
 * we take them out of the Mozilla client altogether.  Fortunately, there is
 * no way to serialize a native function (see fun_xdrObject in jsfun.c).
 */

static JSBool
script_freeze(JSContext *cx, JSObject *obj, uintN argc, jsval *argv,
              jsval *rval)
{
    JSXDRState *xdr;
    JSScript *script;
    JSBool ok, hasMagic;
    uint32 len;
    void *buf;
    JSString *str;

    if (!JS_InstanceOf(cx, obj, &js_ScriptClass, argv))
        return JS_FALSE;
    script = (JSScript *) JS_GetPrivate(cx, obj);
    if (!script)
        return JS_TRUE;

    /* create new XDR */
    xdr = JS_XDRNewMem(cx, JSXDR_ENCODE);
    if (!xdr)
        return JS_FALSE;

    /* write  */
    ok = js_XDRScript(xdr, &script, &hasMagic);
    if (!ok)
        goto out;
    if (!hasMagic) {
        *rval = JSVAL_VOID;
        goto out;
    }

    buf = JS_XDRMemGetData(xdr, &len);
    if (!buf) {
        ok = JS_FALSE;
        goto out;
    }

    JS_ASSERT((jsword)buf % sizeof(jschar) == 0);
    len /= sizeof(jschar);
    str = JS_NewUCStringCopyN(cx, (jschar *)buf, len);
    if (!str) {
        ok = JS_FALSE;
        goto out;
    }

#if IS_BIG_ENDIAN
  {
    jschar *chars;
    uint32 i;

    /* Swap bytes in Unichars to keep frozen strings machine-independent. */
    chars = JS_GetStringChars(str);
    for (i = 0; i < len; i++)
        chars[i] = JSXDR_SWAB16(chars[i]);
  }
#endif
    *rval = STRING_TO_JSVAL(str);

out:
    JS_XDRDestroy(xdr);
    return ok;
}

static JSBool
script_thaw(JSContext *cx, JSObject *obj, uintN argc, jsval *argv,
            jsval *rval)
{
    JSXDRState *xdr;
    JSString *str;
    void *buf;
    uint32 len;
    JSScript *script, *oldscript;
    JSBool ok, hasMagic;

    if (!JS_InstanceOf(cx, obj, &js_ScriptClass, argv))
        return JS_FALSE;

    if (argc == 0)
        return JS_TRUE;
    str = js_ValueToString(cx, argv[0]);
    if (!str)
        return JS_FALSE;

    /* create new XDR */
    xdr = JS_XDRNewMem(cx, JSXDR_DECODE);
    if (!xdr)
        return JS_FALSE;

    buf = JS_GetStringChars(str);
    len = JS_GetStringLength(str);
#if IS_BIG_ENDIAN
  {
    jschar *from, *to;
    uint32 i;

    /* Swap bytes in Unichars to keep frozen strings machine-independent. */
    from = (jschar *)buf;
    to = (jschar *) JS_malloc(cx, len * sizeof(jschar));
    if (!to) {
        JS_XDRDestroy(xdr);
        return JS_FALSE;
    }
    for (i = 0; i < len; i++)
        to[i] = JSXDR_SWAB16(from[i]);
    buf = (char *)to;
  }
#endif
    len *= sizeof(jschar);
    JS_XDRMemSetData(xdr, buf, len);

    /* XXXbe should magic mismatch be error, or false return value? */
    ok = js_XDRScript(xdr, &script, &hasMagic);
    if (!ok)
        goto out;
    if (!hasMagic) {
        *rval = JSVAL_FALSE;
        goto out;
    }

    /* Swap script for obj's old script, if any. */
    oldscript = (JSScript *) JS_GetPrivate(cx, obj);
    ok = JS_SetPrivate(cx, obj, script);
    if (!ok) {
        JS_free(cx, script);
        goto out;
    }
    if (oldscript)
        js_DestroyScript(cx, oldscript);

    script->object = obj;
    js_CallNewScriptHook(cx, script, NULL);

out:
    /*
     * We reset the buffer to be NULL so that it doesn't free the chars
     * memory owned by str (argv[0]).
     */
    JS_XDRMemSetData(xdr, NULL, 0);
    JS_XDRDestroy(xdr);
#if IS_BIG_ENDIAN
    JS_free(cx, buf);
#endif
    *rval = JSVAL_TRUE;
    return ok;
}

static const char js_thaw_str[] = "thaw";

#endif /* JS_HAS_XDR_FREEZE_THAW */
#endif /* JS_HAS_XDR */

static JSFunctionSpec script_methods[] = {
#if JS_HAS_TOSOURCE
    {js_toSource_str,   script_toSource,        0,0,0},
#endif
    {js_toString_str,   script_toString,        0,0,0},
    {"compile",         script_compile,         2,0,0},
    {"exec",            script_exec,            1,0,0},
#if JS_HAS_XDR_FREEZE_THAW
    {"freeze",          script_freeze,          0,0,0},
    {js_thaw_str,       script_thaw,            1,0,0},
#endif /* JS_HAS_XDR_FREEZE_THAW */
    {0,0,0,0,0}
};

#endif /* JS_HAS_SCRIPT_OBJECT */

static void
script_finalize(JSContext *cx, JSObject *obj)
{
    JSScript *script;

    script = (JSScript *) JS_GetPrivate(cx, obj);
    if (script)
        js_DestroyScript(cx, script);
}

static JSBool
script_call(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
{
#if JS_HAS_SCRIPT_OBJECT
    return script_exec(cx, JSVAL_TO_OBJECT(argv[-2]), argc, argv, rval);
#else
    return JS_FALSE;
#endif
}

static uint32
script_mark(JSContext *cx, JSObject *obj, void *arg)
{
    JSScript *script;

    script = (JSScript *) JS_GetPrivate(cx, obj);
    if (script)
        js_MarkScript(cx, script, arg);
    return 0;
}

JS_FRIEND_DATA(JSClass) js_ScriptClass = {
    js_Script_str,
    JSCLASS_HAS_PRIVATE,
    JS_PropertyStub,  JS_PropertyStub,  JS_PropertyStub,  JS_PropertyStub,
    JS_EnumerateStub, JS_ResolveStub,   JS_ConvertStub,   script_finalize,
    NULL,             NULL,             script_call,      NULL,/*XXXbe xdr*/
    NULL,             NULL,             script_mark,      0
};

#if JS_HAS_SCRIPT_OBJECT

static JSBool
Script(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
{
    /* If not constructing, replace obj with a new Script object. */
    if (!(cx->fp->flags & JSFRAME_CONSTRUCTING)) {
        obj = js_NewObject(cx, &js_ScriptClass, NULL, NULL);
        if (!obj)
            return JS_FALSE;
    }
    return script_compile(cx, obj, argc, argv, rval);
}

#if JS_HAS_XDR_FREEZE_THAW

static JSBool
script_static_thaw(JSContext *cx, JSObject *obj, uintN argc, jsval *argv,
                   jsval *rval)
{
    obj = js_NewObject(cx, &js_ScriptClass, NULL, NULL);
    if (!obj)
        return JS_FALSE;
    if (!script_thaw(cx, obj, argc, argv, rval))
        return JS_FALSE;
    *rval = OBJECT_TO_JSVAL(obj);
    return JS_TRUE;
}

static JSFunctionSpec script_static_methods[] = {
    {js_thaw_str,       script_static_thaw,     1,0,0},
    {0,0,0,0,0}
};

#else  /* !JS_HAS_XDR_FREEZE_THAW */