unsigned lastUsed;
};
- // notice that we must use an accessor function and not a static variable
- // because when the TLS variables support is implemented in the library (and
- // not by the compiler), the global s_cache variable could be not yet
- // initialized when a ctor of another global object is executed and if that
- // ctor uses any wxString methods, bad things happen
+#ifndef wxHAS_COMPILER_TLS
+ // we must use an accessor function and not a static variable when the TLS
+ // variables support is implemented in the library (and not by the compiler)
+ // because the global s_cache variable could be not yet initialized when a
+ // ctor of another global object is executed and if that ctor uses any
+ // wxString methods, bad things happen
//
- // also note that for the same reason this function _is_ MT-safe: we know
- // it's going to be called during the program startup (currently during
- // globals initialization but even if they ever stop using wxString, it would
- // still be called by wxInitialize()), i.e. before any threads are created
- static Cache& GetCache()
+ // however notice that this approach does not work when compiler TLS is used,
+ // at least not with g++ 4.1.2 under amd64 as it apparently compiles code
+ // using this accessor incorrectly when optimizations are enabled (-O2 is
+ // enough) -- luckily we don't need it then neither as static __thread
+ // variables are initialized by 0 anyhow then and so we can use the variable
+ // directly
+ WXEXPORT static Cache& GetCache()
{
static wxTLS_TYPE(Cache) s_cache;
return wxTLS_VALUE(s_cache);
}
+
+ // this helper struct is used to ensure that GetCache() is called during
+ // static initialization time, i.e. before any threads creation, as otherwise
+ // the static s_cache construction inside GetCache() wouldn't be MT-safe
+ friend struct wxStrCacheInitializer;
+#else // wxHAS_COMPILER_TLS
+ static wxTLS_TYPE(Cache) ms_cache;
+ static Cache& GetCache() { return wxTLS_VALUE(ms_cache); }
+#endif // !wxHAS_COMPILER_TLS/wxHAS_COMPILER_TLS
static Cache::Element *GetCacheBegin() { return GetCache().cached; }
static Cache::Element *GetCacheEnd() { return GetCacheBegin() + Cache::SIZE; }
static unsigned& LastUsedCacheElement() { return GetCache().lastUsed; }
+ // this is used in debug builds only to provide a convenient function,
+ // callable from a debugger, to show the cache contents
friend struct wxStrCacheDumper;
// uncomment this to have access to some profiling statistics on program
lenhits; // number of cache hits in length()
} ms_cacheStats;
- friend struct ShowCacheStats;
+ friend struct wxStrCacheStatsDumper;
#define wxCACHE_PROFILE_FIELD_INC(field) ms_cacheStats.field++
#define wxCACHE_PROFILE_FIELD_ADD(field, val) ms_cacheStats.field += (val)
// profiling seems to show a small but consistent gain if we use this
// simple loop instead of starting from the last used element (there are
// a lot of misses in this function...)
- for ( Cache::Element *c = GetCacheBegin(); c != GetCacheEnd(); c++ )
+ Cache::Element * const cacheBegin = GetCacheBegin();
+#ifndef wxHAS_COMPILER_TLS
+ // during destruction tls calls may return NULL, in this case return NULL
+ // immediately without accessing anything else
+ if ( cacheBegin == NULL )
+ return NULL;
+#endif
+ Cache::Element * const cacheEnd = GetCacheEnd();
+ for ( Cache::Element *c = cacheBegin; c != cacheEnd; c++ )
{
if ( c->str == this )
return c;
// used for length caching only so far, i.e. it doesn't count as a hit
// from our point of view
if ( cache->pos )
+ {
wxCACHE_PROFILE_FIELD_INC(poshits);
+ }
if ( pos == cache->pos )
return cache->impl;
#else
#define WX_STR_ITERATOR_TAG std::random_access_iterator_tag
#endif
- #define WX_STR_ITERATOR_CATEGORY typedef WX_STR_ITERATOR_TAG iterator_category;
+ #define WX_DEFINE_ITERATOR_CATEGORY(cat) typedef cat iterator_category;
#else
// not defining iterator_category at all in this case is better than defining
// it as some dummy type -- at least it results in more intelligible error
// messages
- #define WX_STR_ITERATOR_CATEGORY
+ #define WX_DEFINE_ITERATOR_CATEGORY(cat)
#endif
#define WX_STR_ITERATOR_IMPL(iterator_name, pointer_type, reference_type) \
private: \
typedef wxStringImpl::iterator_name underlying_iterator; \
public: \
- WX_STR_ITERATOR_CATEGORY \
+ WX_DEFINE_ITERATOR_CATEGORY(WX_STR_ITERATOR_TAG) \
typedef wxUniChar value_type; \
typedef int difference_type; \
typedef reference_type reference; \
public:
typedef T iterator_type;
- typedef typename T::iterator_category iterator_category;
+ WX_DEFINE_ITERATOR_CATEGORY(typename T::iterator_category)
typedef typename T::value_type value_type;
typedef typename T::difference_type difference_type;
typedef typename T::reference reference;
// truncate the string to given length
wxString& Truncate(size_t uiLen);
// empty string contents
- void Empty()
- {
- Truncate(0);
-
- wxASSERT_MSG( empty(), _T("string not empty after call to Empty()?") );
- }
+ void Empty() { clear(); }
// empty the string and free memory
void Clear() { clear(); }
{ return at(n); }
#endif // size_t != unsigned int
- // explicit conversion to C string (use this with printf()!)
+
+ /*
+ Overview of wxString conversions, implicit and explicit:
+
+ - wxString has a std::[w]string-like c_str() method, however it does
+ not return a C-style string directly but instead returns wxCStrData
+ helper object which is convertible to either "char *" narrow string
+ or "wchar_t *" wide string. Usually the correct conversion will be
+ applied by the compiler automatically but if this doesn't happen you
+ need to explicitly choose one using wxCStrData::AsChar() or AsWChar()
+ methods or another wxString conversion function.
+
+ - One of the places where the conversion does *NOT* happen correctly is
+ when c_str() is passed to a vararg function such as printf() so you
+ must *NOT* use c_str() with them. Either use wxPrintf() (all wx
+ functions do handle c_str() correctly, even if they appear to be
+ vararg (but they're not, really)) or add an explicit AsChar() or, if
+ compatibility with previous wxWidgets versions is important, add a
+ cast to "const char *".
+
+ - In non-STL mode only, wxString is also implicitly convertible to
+ wxCStrData. The same warning as above applies.
+
+ - c_str() is polymorphic as it can be converted to either narrow or
+ wide string. If you explicitly need one or the other, choose to use
+ mb_str() (for narrow) or wc_str() (for wide) instead. Notice that
+ these functions can return either the pointer to string directly (if
+ this is what the string uses internally) or a temporary buffer
+ containing the string and convertible to it. Again, conversion will
+ usually be done automatically by the compiler but beware of the
+ vararg functions: you need an explicit cast when using them.
+
+ - There are also non-const versions of mb_str() and wc_str() called
+ char_str() and wchar_str(). They are only meant to be used with
+ non-const-correct functions and they always return buffers.
+
+ - Finally wx_str() returns whatever string representation is used by
+ wxString internally. It may be either a narrow or wide string
+ depending on wxWidgets build mode but it will always be a raw pointer
+ (and not a buffer).
+ */
+
+ // explicit conversion to wxCStrData
wxCStrData c_str() const { return wxCStrData(this); }
wxCStrData data() const { return c_str(); }
- // implicit conversion to C string
+ // implicit conversion to wxCStrData
operator wxCStrData() const { return c_str(); }
// the first two operators conflict with operators for conversion to
projects / wxWidgets.git / blobdiff