wtf/text/StringStatics.cpp

   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 "DynamicAnnotations.h"
  34 #include "StaticConstructors.h"
  35 #include "StringImpl.h"
  36
  37 namespace WTF {
  38
  39 StringImpl* StringImpl::empty()
  40 {
  41     // FIXME: This works around a bug in our port of PCRE, that a regular expression
  42     // run on the empty string may still perform a read from the first element, and
  43     // as such we need this to be a valid pointer. No code should ever be reading
  44     // from a zero length string, so this should be able to be a non-null pointer
  45     // into the zero-page.
  46     // Replace this with 'reinterpret_cast<UChar*>(static_cast<intptr_t>(1))' once
  47     // PCRE goes away.
  48     static UChar emptyUCharData = 0;
  49     DEFINE_STATIC_LOCAL(StringImpl, emptyString, (&emptyUCharData, 0, ConstructStaticString));
  50     WTF_ANNOTATE_BENIGN_RACE(&emptyString, "Benign race on StringImpl::emptyString reference counter");
  51     return &emptyString;
  52 }
  53
  54 JS_EXPORTDATA DEFINE_GLOBAL(AtomicString, nullAtom)
  55 JS_EXPORTDATA DEFINE_GLOBAL(AtomicString, emptyAtom, "")
  56 JS_EXPORTDATA DEFINE_GLOBAL(AtomicString, textAtom, "#text")
  57 JS_EXPORTDATA DEFINE_GLOBAL(AtomicString, commentAtom, "#comment")
  58 JS_EXPORTDATA DEFINE_GLOBAL(AtomicString, starAtom, "*")
  59 JS_EXPORTDATA DEFINE_GLOBAL(AtomicString, xmlAtom, "xml")
  60 JS_EXPORTDATA DEFINE_GLOBAL(AtomicString, xmlnsAtom, "xmlns")
  61
  62 void AtomicString::init()
  63 {
  64     static bool initialized;
  65     if (!initialized) {
  66         // On iPhone WebKit, isMainThread() tests for the Web Thread, so use pthread_main_np() instead.
  67         ASSERT(pthread_main_np());
  68
  69         // Use placement new to initialize the globals.
  70         new ((void*)&nullAtom) AtomicString;
  71         new ((void*)&emptyAtom) AtomicString("");
  72         new ((void*)&textAtom) AtomicString("#text");
  73         new ((void*)&commentAtom) AtomicString("#comment");
  74         new ((void*)&starAtom) AtomicString("*");
  75         new ((void*)&xmlAtom) AtomicString("xml");
  76         new ((void*)&xmlnsAtom) AtomicString("xmlns");
  77
  78         initialized = true;
  79     }
  80 }
  81
  82 }