source: trunk/essentials/dev-lang/python/PC/import_nt.c@ 3315

/********************************************************************

 import_nt.c 

  Win32 specific import code.

*/

#include "Python.h"
#include "osdefs.h"
#include <windows.h>
#include "importdl.h"
#include "malloc.h" /* for alloca */

/* a string loaded from the DLL at startup */
extern const char *PyWin_DLLVersionString;

FILE *PyWin_FindRegisteredModule(const char *moduleName,
                                 struct filedescr **ppFileDesc,
                                 char *pathBuf,
                                 Py_ssize_t pathLen)
{
        char *moduleKey;
        const char keyPrefix[] = "Software\\Python\\PythonCore\\";
        const char keySuffix[] = "\\Modules\\";
#ifdef _DEBUG
        /* In debugging builds, we _must_ have the debug version
         * registered.
         */
        const char debugString[] = "\\Debug";
#else
        const char debugString[] = "";
#endif
        struct filedescr *fdp = NULL;
        FILE *fp;
        HKEY keyBase = HKEY_CURRENT_USER;
        int modNameSize;
        long regStat;

        /* Calculate the size for the sprintf buffer.
         * Get the size of the chars only, plus 1 NULL.
         */
        size_t bufSize = sizeof(keyPrefix)-1 +
                         strlen(PyWin_DLLVersionString) +
                         sizeof(keySuffix) +
                         strlen(moduleName) +
                         sizeof(debugString) - 1;
        /* alloca == no free required, but memory only local to fn,
         * also no heap fragmentation!
         */
        moduleKey = alloca(bufSize); 
        PyOS_snprintf(moduleKey, bufSize,
                      "Software\\Python\\PythonCore\\%s\\Modules\\%s%s",
                      PyWin_DLLVersionString, moduleName, debugString);

        assert(pathLen < INT_MAX);
        modNameSize = (int)pathLen;
        regStat = RegQueryValue(keyBase, moduleKey, pathBuf, &modNameSize);
        if (regStat != ERROR_SUCCESS) {
                /* No user setting - lookup in machine settings */
                keyBase = HKEY_LOCAL_MACHINE;
                /* be anal - failure may have reset size param */
                modNameSize = (int)pathLen;
                regStat = RegQueryValue(keyBase, moduleKey, 
                                        pathBuf, &modNameSize);

                if (regStat != ERROR_SUCCESS)
                        return NULL;
        }
        /* use the file extension to locate the type entry. */
        for (fdp = _PyImport_Filetab; fdp->suffix != NULL; fdp++) {
                size_t extLen = strlen(fdp->suffix);
                assert(modNameSize >= 0); /* else cast to size_t is wrong */
                if ((size_t)modNameSize > extLen &&
                    strnicmp(pathBuf + ((size_t)modNameSize-extLen-1),
                             fdp->suffix,
                             extLen) == 0)
                        break;
        }
        if (fdp->suffix == NULL)
                return NULL;
        fp = fopen(pathBuf, fdp->mode);
        if (fp != NULL)
                *ppFileDesc = fdp;
        return fp;
}