[Python-checkins] CVS: python/dist/src/Modules zlibmodule.c,2.43,2.44

2001年10月16日 13:39:51 -0700

Update of /cvsroot/python/python/dist/src/Modules
In directory usw-pr-cvs1:/tmp/cvs-serv21328/Modules
Modified Files:
	zlibmodule.c 
Log Message:
[ #403753 ] zlib decompress; uncontrollable memory usage
Mostly by Toby Dickenson and Titus Brown.
Add an optional argument to a decompression object's decompress()
method. The argument specifies the maximum length of the return
value. If the uncompressed data exceeds this length, the excess data
is stored as the unconsumed_tail attribute. (Not to be confused with
unused_data, which is a separate issue.)
Difference from SF patch: Default value for unconsumed_tail is ""
rather than None. It's simpler if the attribute is always a string.
Index: zlibmodule.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Modules/zlibmodule.c,v
retrieving revision 2.43
retrieving revision 2.44
diff -C2 -d -r2.43 -r2.44
*** zlibmodule.c	2001年10月09日 10:54:31	2.43
--- zlibmodule.c	2001年10月16日 20:39:49	2.44
***************
*** 79,82 ****
--- 79,83 ----
 z_stream zst;
 PyObject *unused_data;
+ PyObject *unconsumed_tail;
 int is_initialised;
 } compobject;
***************
*** 101,104 ****
--- 102,114 ----
 	self->is_initialised = 0;
 	self->unused_data = PyString_FromString("");
+ 	if (self->unused_data == NULL) {
+ 	 Py_DECREF(self);
+ 	 return NULL;
+ 	}
+ 	self->unconsumed_tail = PyString_FromString("");
+ 	if (self->unconsumed_tail == NULL) {
+ 	 Py_DECREF(self);
+ 	 return NULL;
+ 	}
 return self;
 }
***************
*** 486,489 ****
--- 496,500 ----
 deflateEnd(&self->zst);
 Py_XDECREF(self->unused_data);
+ Py_XDECREF(self->unconsumed_tail);
 PyObject_Del(self);

***************
*** 499,502 ****
--- 510,514 ----
 inflateEnd(&self->zst);
 Py_XDECREF(self->unused_data);
+ Py_XDECREF(self->unconsumed_tail);
 PyObject_Del(self);

***************
*** 596,603 ****

 static char decomp_decompress__doc__[] =
! "decompress(data) -- Return a string containing the decompressed version of the data.\n\n"
 "After calling this function, some of the input data may still\n"
 "be stored in internal buffers for later processing.\n"
! "Call the flush() method to clear these buffers."
 ;

--- 608,619 ----

 static char decomp_decompress__doc__[] =
! "decompress(data, max_length) -- Return a string containing\n"
! "the decompressed version of the data.\n\n"
 "After calling this function, some of the input data may still\n"
 "be stored in internal buffers for later processing.\n"
! "Call the flush() method to clear these buffers.\n"
! "If the max_length parameter is specified then the return value will be\n"
! "no longer than max_length. Unconsumed input data will be stored in\n"
! "the unconsumed_tail attribute."
 ;

***************
*** 605,609 ****
 PyZlib_objdecompress(compobject *self, PyObject *args)
 {
! int err, inplen, length = DEFAULTALLOC;
 PyObject *RetVal;
 Byte *input;
--- 621,626 ----
 PyZlib_objdecompress(compobject *self, PyObject *args)
 {
! int err, inplen, old_length, length = DEFAULTALLOC;
! int max_length = 0;
 PyObject *RetVal;
 Byte *input;
***************
*** 612,620 ****
 PyObject * inputString;

! if (!PyArg_ParseTuple(args, "S:decompress", &inputString))
 return NULL;
 if (PyString_AsStringAndSize(inputString, (char**)&input, &inplen) == -1)
 return NULL;

 if (!(RetVal = PyString_FromStringAndSize(NULL, length))) {
 PyErr_SetString(PyExc_MemoryError,
--- 629,646 ----
 PyObject * inputString;

! if (!PyArg_ParseTuple(args, "S|i:decompress", &inputString, &max_length))
! return NULL;
! if (max_length < 0) {
! PyErr_SetString(PyExc_ValueError,
! 		 "max_length must be greater than zero");
 return NULL;
+ }
+ 
 if (PyString_AsStringAndSize(inputString, (char**)&input, &inplen) == -1)
 return NULL;

+ /* limit amount of data allocated to max_length */
+ if (max_length && length > max_length) 
+ length = max_length;
 if (!(RetVal = PyString_FromStringAndSize(NULL, length))) {
 PyErr_SetString(PyExc_MemoryError,
***************
*** 638,645 ****
 Py_END_ALLOW_THREADS

! /* while Z_OK and the output buffer is full, there might be more output,
! so extend the output buffer and try again */
 while (err == Z_OK && self->zst.avail_out == 0) { 
! if (_PyString_Resize(&RetVal, length << 1) == -1) {
 PyErr_SetString(PyExc_MemoryError,
 "Can't allocate memory to compress data");
--- 664,684 ----
 Py_END_ALLOW_THREADS

! /* While Z_OK and the output buffer is full, there might be more output.
! So extend the output buffer and try again.
! */
 while (err == Z_OK && self->zst.avail_out == 0) { 
! /* If max_length set, don't continue decompressing if we've already
! reached the limit.
! */
! if (max_length && length >= max_length)
! break;
! 
! /* otherwise, ... */
! old_length = length;
! length = length << 1;
! if (max_length && length > max_length) 
! length = max_length;
! 
! if (_PyString_Resize(&RetVal, length) == -1) {
 PyErr_SetString(PyExc_MemoryError,
 "Can't allocate memory to compress data");
***************
*** 647,653 ****
 break;
 }
! self->zst.next_out = (unsigned char *)PyString_AsString(RetVal) + length;
! self->zst.avail_out = length;
! length = length << 1;
 Py_BEGIN_ALLOW_THREADS
 err = inflate(&(self->zst), Z_SYNC_FLUSH);
--- 686,692 ----
 break;
 }
! self->zst.next_out = (unsigned char *)PyString_AsString(RetVal)+old_length;
! self->zst.avail_out = length - old_length;
! 
 Py_BEGIN_ALLOW_THREADS
 err = inflate(&(self->zst), Z_SYNC_FLUSH);
***************
*** 655,658 ****
--- 694,707 ----
 }

+ /* Not all of the compressed data could be accomodated in the output buffer
+ of specified size. Return the unconsumed tail in an attribute.*/
+ if(max_length) {
+ Py_DECREF(self->unconsumed_tail);
+ self->unconsumed_tail = PyString_FromStringAndSize(self->zst.next_in, 
+ 						 self->zst.avail_in);
+ if(!self->unconsumed_tail)
+ return_error = 1;
+ }
+ 
 /* The end of the compressed data has been reached, so set the unused_data 
 attribute to a string containing the remainder of the data in the string. 
***************
*** 885,888 ****
--- 934,942 ----
 	 Py_INCREF(self->unused_data);
 retval = self->unused_data;
+ 	 }
+ 	else if (strcmp(name, "unconsumed_tail") == 0) 
+ 	 { 
+ 	 Py_INCREF(self->unconsumed_tail);
+ 	 retval = self->unconsumed_tail;
 	 }
 	else 