1 /*

     2  * Copyright (C) 2010 Apple Inc. All Rights Reserved.

     3  *

     4  * Redistribution and use in source and binary forms, with or without

     5  * modification, are permitted provided that the following conditions

     6  * are met:

     7  * 1. Redistributions of source code must retain the above copyright

     8  *    notice, this list of conditions and the following disclaimer.

     9  * 2. Redistributions in binary form must reproduce the above copyright

    10  *    notice, this list of conditions and the following disclaimer in the

    11  *    documentation and/or other materials provided with the distribution.

    12  *

    13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY

    14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

    15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

    16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR

    17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

    18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

    19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

    20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

    21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

    22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

    23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    24  */

    25 

    26 #include "config.h"

    27 

    28 #ifdef SKIP_STATIC_CONSTRUCTORS_ON_GCC

    29 #define ATOMICSTRING_HIDE_GLOBALS 1

    30 #endif

    31 

    32 #include "AtomicString.h"

    33 #include "StaticConstructors.h"

    34 #include "StringImpl.h"

    35 

    36 namespace WebCore {

    37 

    38 StringImpl* StringImpl::empty()

    39 {

    40     // FIXME: This works around a bug in our port of PCRE, that a regular expression

    41     // run on the empty string may still perform a read from the first element, and

    42     // as such we need this to be a valid pointer. No code should ever be reading

    43     // from a zero length string, so this should be able to be a non-null pointer

    44     // into the zero-page.

    45     // Replace this with 'reinterpret_cast<UChar*>(static_cast<intptr_t>(1))' once

    46     // PCRE goes away.

    47     static UChar emptyUCharData = 0;

    48     DEFINE_STATIC_LOCAL(StringImpl, emptyString, (&emptyUCharData, 0, ConstructStaticString));

    49     return &emptyString;

    50 }

    51 /*

    52 JS_EXPORTDATA DEFINE_GLOBAL(AtomicString, nullAtom)

    53 JS_EXPORTDATA DEFINE_GLOBAL(AtomicString, emptyAtom, "")

    54 JS_EXPORTDATA DEFINE_GLOBAL(AtomicString, textAtom, "#text")

    55 JS_EXPORTDATA DEFINE_GLOBAL(AtomicString, commentAtom, "#comment")

    56 JS_EXPORTDATA DEFINE_GLOBAL(AtomicString, starAtom, "*")

    57 JS_EXPORTDATA DEFINE_GLOBAL(AtomicString, xmlAtom, "xml")

    58 JS_EXPORTDATA DEFINE_GLOBAL(AtomicString, xmlnsAtom, "xmlns")

    59 */

    60 AtomicString nullAtom1;

    61 AtomicString emptyAtom1;

    62 AtomicString textAtom1;

    63 AtomicString commentAtom1;

    64 AtomicString starAtom1;

    65 AtomicString xmlAtom1;

    66 AtomicString xmlnsAtom1;

    67 

    68 void AtomicString::init()

    69 {

    70     static bool initialized;

    71     if (!initialized) {

    72         // Initialization is not thread safe, so this function must be called from the main thread first.

    73         ASSERT(isMainThread());

    74 

    75         // Use placement new to initialize the globals.

    76         new ((void*)&nullAtom1) AtomicString;

    77         new ((void*)&emptyAtom1) AtomicString("");

    78         new ((void*)&textAtom1) AtomicString("#text");

    79         new ((void*)&commentAtom1) AtomicString("#comment");

    80         new ((void*)&starAtom1) AtomicString("*");

    81         new ((void*)&xmlAtom1) AtomicString("xml");

    82         new ((void*)&xmlnsAtom1) AtomicString("xmlns");

    83 

    84         initialized = true;

    85     }

    86 }

    87 

    88 const AtomicString& AtomicString::nullAtom2() { return nullAtom1;}

    89 const AtomicString& AtomicString::emptyAtom2() { return emptyAtom1;}

    90 const AtomicString& AtomicString::textAtom2() { return textAtom1;}

    91 const AtomicString& AtomicString::commentAtom2() { return commentAtom1;}

    92 const AtomicString& AtomicString::starAtom2() { return starAtom1;}

    93 const AtomicString& AtomicString::xmlAtom2() { return xmlAtom1;}

    94 const AtomicString& AtomicString::xmlnsAtom2() { return xmlnsAtom1;}

    95 

    96 }