gecko/js/xpconnect/loader/mozJSLoaderUtils.cpp

/* ***** 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,
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 * for the specific language governing rights and limitations under the
 * License.
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 * The Original Code is mozilla.org
 *
 * The Initial Developer of the Original Code is
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 * Portions created by the Initial Developer are Copyright (C) 2010-2011
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Michael Wu <mwu@mozilla.com>
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 * 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"),
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#include "nsAutoPtr.h"
#include "nsScriptLoader.h"

#include "jsapi.h"
#include "jsdbgapi.h"

#include "nsJSPrincipals.h"

#include "mozilla/scache/StartupCache.h"
#include "mozilla/scache/StartupCacheUtils.h"

using namespace mozilla::scache;

// We only serialize scripts with system principals. So we don't serialize the
// principals when writing a script. Instead, when reading it back, we set the
// principals to the system principals.
nsresult
ReadCachedScript(StartupCache* cache, nsACString &uri, JSContext *cx,
                 nsIPrincipal *systemPrincipal, JSScript **scriptp)
{
    nsAutoArrayPtr<char> buf;
    PRUint32 len;
    nsresult rv = cache->GetBuffer(PromiseFlatCString(uri).get(),
                                   getter_Transfers(buf), &len);
    if (NS_FAILED(rv))
        return rv; // don't warn since NOT_AVAILABLE is an ok error

    JSScript *script = JS_DecodeScript(cx, buf, len, nsJSPrincipals::get(systemPrincipal), nsnull);
    if (!script)
        return NS_ERROR_OUT_OF_MEMORY;
    *scriptp = script;
    return NS_OK;
}

nsresult
WriteCachedScript(StartupCache* cache, nsACString &uri, JSContext *cx,
                  nsIPrincipal *systemPrincipal, JSScript *script)
{
    MOZ_ASSERT(JS_GetScriptPrincipals(script) == nsJSPrincipals::get(systemPrincipal));
    MOZ_ASSERT(JS_GetScriptOriginPrincipals(script) == nsJSPrincipals::get(systemPrincipal));

    uint32_t size;
    void *data = JS_EncodeScript(cx, script, &size);
    if (!data)
        return NS_ERROR_OUT_OF_MEMORY;

    MOZ_ASSERT(size);
    nsresult rv = cache->PutBuffer(PromiseFlatCString(uri).get(), static_cast<char *>(data), size);
    js_free(data);
    return rv;
}