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0027345: Foundation Classes, OSD_Environment - use consistent way to retrieve environment variable value on Windows

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OSD_Environment::Value() now uses GetEnvironmentVariableW() instead of _wgetenv()
which might provide outdated variable value cached by C runtime library.
This commit is contained in:
kgv 2017-04-18 14:23:40 +03:00 committed by bugmaster
parent 85719f0ef9
commit e87d0237d8
1 changed files with 21 additions and 17 deletions

38
src/OSD/OSD_Environment.cxx

@ -287,32 +287,36 @@ TCollection_AsciiString OSD_Environment::Value()
Standard_Mutex::Sentry aLock (THE_ENV_LOCK);
THE_ENV_MAP.Find (myName, myValue);
#else
// msvc C-runtime (_wputenv()) puts variable using WinAPI internally (calls SetEnvironmentVariableW())
// and also caches its value in its own map,
// so that _wgetenv() ignores WinAPI and retieves variable from this cache.
//
// Using _wgetenv() might lead to awkward results in context when several C-runtimes are used
// at once within application or WinAPI is used directly for setting environment variable.
//
// Using _wputenv() + GetEnvironmentVariableW() pair should provide most robust behavior in tricky scenarios.
// So that _wgetenv() users will retrieve proper value set by OSD_Environment if used C-runtime library is the same as used by OCCT,
// and OSD_Environment will retreieve most up-to-date value of environment variable nevertheless C-runtime version used (or not used at all) for setting value externally,
// considering msvc C-runtime implementation details.
SetLastError (ERROR_SUCCESS);
wchar_t* anEnvVal = NULL;
NCollection_UtfWideString aNameWide (myName.ToCString());
DWORD aSize = GetEnvironmentVariableW (aNameWide.ToCString(), NULL, 0);
if ((aSize == 0 && GetLastError() != ERROR_SUCCESS)
|| (anEnvVal = _wgetenv (aNameWide.ToCString())) == NULL)
if (aSize == 0 && GetLastError() != ERROR_SUCCESS)
{
_set_error (myError, ERROR_ENVVAR_NOT_FOUND);
return myValue;
}
NCollection_Utf8String aValue;
if (anEnvVal != NULL)
{
aValue.FromUnicode (anEnvVal);
}
else
{
aSize += 1; // NULL-terminator
wchar_t* aBuff = new wchar_t[aSize];
GetEnvironmentVariableW (aNameWide.ToCString(), aBuff, aSize);
aBuff[aSize - 1] = L'\0';
aValue.FromUnicode (aBuff);
delete[] aBuff;
Reset();
}
aSize += 1; // NULL-terminator
wchar_t* aBuff = new wchar_t[aSize];
GetEnvironmentVariableW (aNameWide.ToCString(), aBuff, aSize);
aBuff[aSize - 1] = L'\0';
aValue.FromUnicode (aBuff);
delete[] aBuff;
Reset();
myValue = aValue.ToCString();
#endif
return myValue;