[Python-checkins] python/dist/src/Python import.c,2.192.6.2,2.192.6.3

[gvanrossum@users.sourceforge.net]

Update of /cvsroot/python/python/dist/src/Python
In directory sc8-pr-cvs1:/tmp/cvs-serv3041

Modified Files:
      Tag: release22-maint
	import.c 
Log Message:
Backport 2.217 and 2.218:
Provide access to the import lock, fixing SF bug #580952.  This is
mostly from SF patch #683257, but I had to change unlock_import() to
return an error value to avoid fatal error.


Index: import.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Python/import.c,v
retrieving revision 2.192.6.2
retrieving revision 2.192.6.3
diff -C2 -d -r2.192.6.2 -r2.192.6.3
*** import.c	1 Jun 2002 18:26:22 -0000	2.192.6.2
--- import.c	13 Feb 2003 17:01:28 -0000	2.192.6.3
***************
*** 162,166 ****
  		return;
  	}
! 	if (import_lock_thread != -1 || !PyThread_acquire_lock(import_lock, 0)) {
  		PyThreadState *tstate = PyEval_SaveThread();
  		PyThread_acquire_lock(import_lock, 1);
--- 162,167 ----
  		return;
  	}
! 	if (import_lock_thread != -1 || !PyThread_acquire_lock(import_lock, 0))
! 	{
  		PyThreadState *tstate = PyEval_SaveThread();
  		PyThread_acquire_lock(import_lock, 1);
***************
*** 171,182 ****
  }
  
! static void
  unlock_import(void)
  {
  	long me = PyThread_get_thread_ident();
  	if (me == -1)
! 		return; /* Too bad */
  	if (import_lock_thread != me)
! 		Py_FatalError("unlock_import: not holding the import lock");
  	import_lock_level--;
  	if (import_lock_level == 0) {
--- 172,183 ----
  }
  
! static int
  unlock_import(void)
  {
  	long me = PyThread_get_thread_ident();
  	if (me == -1)
! 		return 0; /* Too bad */
  	if (import_lock_thread != me)
! 		return -1;
  	import_lock_level--;
  	if (import_lock_level == 0) {
***************
*** 184,187 ****
--- 185,189 ----
  		PyThread_release_lock(import_lock);
  	}
+ 	return 1;
  }
  
***************
*** 189,193 ****
  
  #define lock_import()
! #define unlock_import()
  
  #endif
--- 191,195 ----
  
  #define lock_import()
! #define unlock_import() 0
  
  #endif
***************
*** 205,208 ****
--- 207,238 ----
  }
  
+ static PyObject *
+ imp_acquire_lock(PyObject *self, PyObject *args)
+ {
+ 	if (!PyArg_ParseTuple(args, ":acquire_lock"))
+ 		return NULL;
+ #ifdef WITH_THREAD
+ 	lock_import();
+ #endif
+ 	Py_INCREF(Py_None);
+ 	return Py_None;
+ }
+ 
+ static PyObject *
+ imp_release_lock(PyObject *self, PyObject *args)
+ {
+ 	if (!PyArg_ParseTuple(args, ":release_lock"))
+ 		return NULL;
+ #ifdef WITH_THREAD
+ 	if (unlock_import() < 0) {
+ 		PyErr_SetString(PyExc_RuntimeError,
+ 				"not holding the import lock");
+ 		return NULL;
+ 	}
+ #endif
+ 	Py_INCREF(Py_None);
+ 	return Py_None;
+ }
+ 
  /* Helper for sys */
  
***************
*** 1657,1661 ****
  	lock_import();
  	result = import_module_ex(name, globals, locals, fromlist);
! 	unlock_import();
  	return result;
  }
--- 1687,1696 ----
  	lock_import();
  	result = import_module_ex(name, globals, locals, fromlist);
! 	if (unlock_import() < 0) {
! 		Py_XDECREF(result);
! 		PyErr_SetString(PyExc_RuntimeError,
! 				"not holding the import lock");
! 		return NULL;
! 	}
  	return result;
  }
***************
*** 2427,2430 ****
--- 2462,2477 ----
  ";
  
+ static char doc_acquire_lock[] = "\
+ acquire_lock() -> None\n\
+ Acquires the interpreter's import lock for the current thread.\n\
+ This lock should be used by import hooks to ensure thread-safety\n\
+ when importing modules.\n\
+ On platforms without threads, this function does nothing.";
+ 
+ static char doc_release_lock[] = "\
+ release_lock() -> None\n\
+ Release the interpreter's import lock.\n\
+ On platforms without threads, this function does nothing.";
+ 
  static PyMethodDef imp_methods[] = {
  	{"find_module",		imp_find_module,	1, doc_find_module},
***************
*** 2434,2437 ****
--- 2481,2486 ----
  	{"new_module",		imp_new_module,		1, doc_new_module},
  	{"lock_held",		imp_lock_held,		1, doc_lock_held},
+ 	{"acquire_lock",	imp_acquire_lock,	1, doc_acquire_lock},
+ 	{"release_lock",	imp_release_lock,	1, doc_release_lock},
  	/* The rest are obsolete */
  	{"get_frozen_object",	imp_get_frozen_object,	1},