jsxdrapi.c

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    if (xdr->mode == JSXDR_ENCODE) {
        if (!xdr->ops->setbytes(xdr, bytes, len))
            return JS_FALSE;
    } else {
        if (!xdr->ops->getbytes(xdr, bytes, len))
            return JS_FALSE;
    }
    len = xdr->ops->tell(xdr);
    if (len % JSXDR_ALIGN) {
        padlen = JSXDR_ALIGN - (len % JSXDR_ALIGN);
        if (xdr->mode == JSXDR_ENCODE) {
            if (!xdr->ops->setbytes(xdr, padbuf, padlen))
                return JS_FALSE;
        } else {
            if (!xdr->ops->seek(xdr, padlen, JSXDR_SEEK_CUR))
                return JS_FALSE;
        }
    }
    return JS_TRUE;
}

/**
 * Convert between a C string and the XDR representation:
 * leading 32-bit count, then counted vector of chars,
 * then possibly \0 padding to multiple of 4.
 */
JS_PUBLIC_API(JSBool)
JS_XDRCString(JSXDRState *xdr, char **sp)
{
    uint32 len;

    if (xdr->mode == JSXDR_ENCODE)
        len = strlen(*sp);
    JS_XDRUint32(xdr, &len);
    if (xdr->mode == JSXDR_DECODE) {
        if (!(*sp = (char *) JS_malloc(xdr->cx, len + 1)))
            return JS_FALSE;
    }
    if (!JS_XDRBytes(xdr, *sp, len)) {
        if (xdr->mode == JSXDR_DECODE)
            JS_free(xdr->cx, *sp);
        return JS_FALSE;
    }
    if (xdr->mode == JSXDR_DECODE) {
        (*sp)[len] = '\0';
    } else if (xdr->mode == JSXDR_FREE) {
        JS_free(xdr->cx, *sp);
        *sp = NULL;
    }
    return JS_TRUE;
}

JS_PUBLIC_API(JSBool)
JS_XDRCStringOrNull(JSXDRState *xdr, char **sp)
{
    uint32 null = (*sp == NULL);
    if (!JS_XDRUint32(xdr, &null))
        return JS_FALSE;
    if (null) {
        *sp = NULL;
        return JS_TRUE;
    }
    return JS_XDRCString(xdr, sp);
}

/*
 * Convert between a JS (Unicode) string and the XDR representation.
 */
JS_PUBLIC_API(JSBool)
JS_XDRString(JSXDRState *xdr, JSString **strp)
{
    uint32 i, len, padlen, nbytes;
    jschar *chars = NULL, *raw;

    if (xdr->mode == JSXDR_ENCODE)
        len = JSSTRING_LENGTH(*strp);
    if (!JS_XDRUint32(xdr, &len))
        return JS_FALSE;
    nbytes = len * sizeof(jschar);

    if (xdr->mode == JSXDR_DECODE) {
        if (!(chars = (jschar *) JS_malloc(xdr->cx, nbytes + sizeof(jschar))))
            return JS_FALSE;
    } else {
        chars = JSSTRING_CHARS(*strp);
    }

    padlen = nbytes % JSXDR_ALIGN;
    if (padlen) {
        padlen = JSXDR_ALIGN - padlen;
        nbytes += padlen;
    }
    if (!(raw = (jschar *) xdr->ops->raw(xdr, nbytes)))
        goto bad;
    if (xdr->mode == JSXDR_ENCODE) {
        for (i = 0; i < len; i++)
            raw[i] = JSXDR_SWAB16(chars[i]);
        if (padlen)
            memset((char *)raw + nbytes - padlen, 0, padlen);
    } else if (xdr->mode == JSXDR_DECODE) {
        for (i = 0; i < len; i++)
            chars[i] = JSXDR_SWAB16(raw[i]);
        chars[len] = 0;

        if (!(*strp = JS_NewUCString(xdr->cx, chars, len)))
            goto bad;
    }
    return JS_TRUE;

bad:
    if (xdr->mode == JSXDR_DECODE)
        JS_free(xdr->cx, chars);
    return JS_FALSE;
}

JS_PUBLIC_API(JSBool)
JS_XDRStringOrNull(JSXDRState *xdr, JSString **strp)
{
    uint32 null = (*strp == NULL);
    if (!JS_XDRUint32(xdr, &null))
        return JS_FALSE;
    if (null) {
        *strp = NULL;
        return JS_TRUE;
    }
    return JS_XDRString(xdr, strp);
}

JS_PUBLIC_API(JSBool)
JS_XDRDouble(JSXDRState *xdr, jsdouble **dp)
{
    jsdouble d;
    if (xdr->mode == JSXDR_ENCODE)
        d = **dp;
#if IS_BIG_ENDIAN
    if (!JS_XDRUint32(xdr, (uint32 *)&d + 1) ||
        !JS_XDRUint32(xdr, (uint32 *)&d))
#else
    if (!JS_XDRUint32(xdr, (uint32 *)&d) ||
        !JS_XDRUint32(xdr, (uint32 *)&d + 1))
#endif
        return JS_FALSE;
    if (xdr->mode == JSXDR_DECODE) {
        *dp = JS_NewDouble(xdr->cx, d);
        if (!*dp)
            return JS_FALSE;
    }
    return JS_TRUE;
}

/* These are magic pseudo-tags: see jsapi.h, near the top, for real tags. */
#define JSVAL_XDRNULL   0x8
#define JSVAL_XDRVOID   0xA

JS_PUBLIC_API(JSBool)
JS_XDRValue(JSXDRState *xdr, jsval *vp)
{
    uint32 type;
    
    if (xdr->mode == JSXDR_ENCODE) {
        if (JSVAL_IS_NULL(*vp))
            type = JSVAL_XDRNULL;
        else if (JSVAL_IS_VOID(*vp))
            type = JSVAL_XDRVOID;
        else
            type = JSVAL_TAG(*vp);
    }
    if (!JS_XDRUint32(xdr, &type))
        return JS_FALSE;

    switch (type) {
      case JSVAL_XDRNULL:
        *vp = JSVAL_NULL;
        break;
      case JSVAL_XDRVOID:
        *vp = JSVAL_VOID;
        break;
      case JSVAL_STRING: {
        JSString *str;
        if (xdr->mode == JSXDR_ENCODE)
            str = JSVAL_TO_STRING(*vp);
        if (!JS_XDRString(xdr, &str))
            return JS_FALSE;
        if (xdr->mode == JSXDR_DECODE)
            *vp = STRING_TO_JSVAL(str);
        break;
      }
      case JSVAL_DOUBLE: {
        jsdouble *dp;
        if (xdr->mode == JSXDR_ENCODE)
            dp = JSVAL_TO_DOUBLE(*vp);
        if (!JS_XDRDouble(xdr, &dp))
            return JS_FALSE;
        if (xdr->mode == JSXDR_DECODE)
            *vp = DOUBLE_TO_JSVAL(dp);
        break;
      }
      case JSVAL_OBJECT: {
        JSObject *obj;
        if (xdr->mode == JSXDR_ENCODE)
            obj = JSVAL_TO_OBJECT(*vp);
        if (!js_XDRObject(xdr, &obj))
            return JS_FALSE;
        if (xdr->mode == JSXDR_DECODE)
            *vp = OBJECT_TO_JSVAL(obj);
        break;
      }
      case JSVAL_BOOLEAN: {
        uint32 b;
        if (xdr->mode == JSXDR_ENCODE)
            b = (uint32) JSVAL_TO_BOOLEAN(*vp);
        if (!JS_XDRUint32(xdr, &b))
            return JS_FALSE;
        if (xdr->mode == JSXDR_DECODE)
            *vp = BOOLEAN_TO_JSVAL((JSBool) b);
        break;
      }
      default: {
        uint32 i;

        JS_ASSERT(type & JSVAL_INT);
        if (xdr->mode == JSXDR_ENCODE)
            i = (uint32) JSVAL_TO_INT(*vp);
        if (!JS_XDRUint32(xdr, &i))
            return JS_FALSE;
        if (xdr->mode == JSXDR_DECODE)
            *vp = INT_TO_JSVAL((int32) i);
        break;
      }
    }
    return JS_TRUE;
}

JS_PUBLIC_API(JSBool)
JS_XDRScript(JSXDRState *xdr, JSScript **scriptp)
{
    if (!js_XDRScript(xdr, scriptp, NULL))
        return JS_FALSE;
    if (xdr->mode == JSXDR_DECODE)
        js_CallNewScriptHook(xdr->cx, *scriptp, NULL);
    return JS_TRUE;
}

#define CLASS_REGISTRY_MIN      8
#define CLASS_INDEX_TO_ID(i)    ((i)+1)
#define CLASS_ID_TO_INDEX(id)   ((id)-1)

typedef struct JSRegHashEntry {
    JSDHashEntryHdr hdr;
    const char      *name;
    uint32          index;
} JSRegHashEntry;

JS_PUBLIC_API(JSBool)
JS_XDRRegisterClass(JSXDRState *xdr, JSClass *clasp, uint32 *idp)
{
    uintN numclasses, maxclasses;
    JSClass **registry;

    numclasses = xdr->numclasses;
    maxclasses = xdr->maxclasses;
    if (numclasses == maxclasses) {
        maxclasses = (maxclasses == 0) ? CLASS_REGISTRY_MIN : maxclasses << 1;
        registry = (JSClass **)
            JS_realloc(xdr->cx, xdr->registry, maxclasses * sizeof(JSClass *));
        if (!registry)
            return JS_FALSE;
        xdr->registry = registry;
        xdr->maxclasses = maxclasses;
    } else {
        JS_ASSERT(numclasses && numclasses < maxclasses);
        registry = xdr->registry;
    }

    registry[numclasses] = clasp;
    if (xdr->reghash) {
        JSRegHashEntry *entry = (JSRegHashEntry *)
            JS_DHashTableOperate(xdr->reghash, clasp->name, JS_DHASH_ADD);
        if (!entry) {
            JS_ReportOutOfMemory(xdr->cx);
            return JS_FALSE;
        }
        entry->name = clasp->name;
        entry->index = numclasses;
    }
    *idp = CLASS_INDEX_TO_ID(numclasses);
    xdr->numclasses = ++numclasses;
    return JS_TRUE;
}

JS_PUBLIC_API(uint32)
JS_XDRFindClassIdByName(JSXDRState *xdr, const char *name)
{
    uintN i, numclasses;

    numclasses = xdr->numclasses;
    if (numclasses >= 10) {
        JSRegHashEntry *entry;

        /* Bootstrap reghash from registry on first overpopulated Find. */
        if (!xdr->reghash) {
            xdr->reghash = JS_NewDHashTable(JS_DHashGetStubOps(), NULL,
                                            sizeof(JSRegHashEntry),
                                            numclasses);
            if (xdr->reghash) {
                for (i = 0; i < numclasses; i++) {
                    JSClass *clasp = xdr->registry[i];
                    entry = (JSRegHashEntry *)
                        JS_DHashTableOperate(xdr->reghash, clasp->name,
                                             JS_DHASH_ADD);
                    entry->name = clasp->name;
                    entry->index = i;
                }
            }
        }

        /* If we managed to create reghash, use it for O(1) Find. */
        if (xdr->reghash) {
            entry = (JSRegHashEntry *)
                JS_DHashTableOperate(xdr->reghash, name, JS_DHASH_LOOKUP);
            if (JS_DHASH_ENTRY_IS_BUSY(&entry->hdr))
                return CLASS_INDEX_TO_ID(entry->index);
        }
    }

    /* Only a few classes, or we couldn't malloc reghash: use linear search. */
    for (i = 0; i < numclasses; i++) {
        if (!strcmp(name, xdr->registry[i]->name))
            return CLASS_INDEX_TO_ID(i);
    }
    return 0;
}

JS_PUBLIC_API(JSClass *)
JS_XDRFindClassById(JSXDRState *xdr, uint32 id)
{
    uintN i = CLASS_ID_TO_INDEX(id);

    if (i >= xdr->numclasses)
        return NULL;
    return xdr->registry[i];
}

#endif /* JS_HAS_XDR */