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Simplify and fix error handling for most cases.

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Many functions used a local variable called return_error, which was
initialized to zero.  If an error occurred, it was set to true.  Most
of the code paths checked were only executed if return_error was
false.  goto is clearer.

The code also seemed to be written under the curious assumption that
calling Py_DECREF() on a local variable would assign the variable to
NULL.  As a result, more of the error-exit code paths returned an
object that had a reference count of zero instead of just returning
NULL.  Fixed the code to explicitly assign NULL after the DECREF.

A bit more reformatting, but not much.

XXX Need a much better test suite for zlib, since it the current tests
don't exercise any of this broken code.
This commit is contained in:
Jeremy Hylton 2001-10-16 23:02:32 +00:00
parent 61acf067ac
commit 9d620d018c
1 changed files with 112 additions and 166 deletions
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172
Modules/zlibmodule.c
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@ -136,7 +136,6 @@ PyZlib_compress(PyObject *self, PyObject *args)
Byte *input, *output;
int length, level=Z_DEFAULT_COMPRESSION, err;
z_stream zst;
int return_error;
PyObject * inputString;
/* require Python string object, optional 'level' arg */
@ -150,8 +149,7 @@ PyZlib_compress(PyObject *self, PyObject *args)
zst.avail_out = length + length/1000 + 12 + 1;
output = (Byte*)malloc(zst.avail_out);
if (output==NULL)
{
if (output == NULL) {
PyErr_SetString(PyExc_MemoryError,
"Can't allocate memory to compress data");
return NULL;
@ -169,28 +167,23 @@ PyZlib_compress(PyObject *self, PyObject *args)
zst.avail_in = length;
err = deflateInit(&zst, level);
return_error = 0;
switch(err)
{
switch(err) {
case(Z_OK):
break;
case(Z_MEM_ERROR):
PyErr_SetString(PyExc_MemoryError,
"Out of memory while compressing data");
return_error = 1;
break;
goto error;
case(Z_STREAM_ERROR):
PyErr_SetString(ZlibError,
"Bad compression level");
return_error = 1;
break;
goto error;
default:
deflateEnd(&zst);
zlib_error(zst, err, "while compressing data");
return_error = 1;
goto error;
}
if (!return_error) {
Py_BEGIN_ALLOW_THREADS;
err = deflate(&zst, Z_FINISH);
Py_END_ALLOW_THREADS;
@ -198,19 +191,17 @@ PyZlib_compress(PyObject *self, PyObject *args)
if (err != Z_STREAM_END) {
zlib_error(zst, err, "while compressing data");
deflateEnd(&zst);
return_error = 1;
goto error;
}
if (!return_error) {
err=deflateEnd(&zst);
if (err == Z_OK)
ReturnVal = PyString_FromStringAndSize((char *)output,
zst.total_out);
else
zlib_error(zst, err, "while finishing compression");
}
}
error:
free(output);
Py_DECREF(inputString);
@ -231,7 +222,6 @@ PyZlib_decompress(PyObject *self, PyObject *args)
int length, err;
int wsize=DEF_WBITS, r_strlen=DEFAULTALLOC;
z_stream zst;
int return_error;
PyObject * inputString;
if (!PyArg_ParseTuple(args, "S|ii:decompress",
@ -260,24 +250,20 @@ PyZlib_decompress(PyObject *self, PyObject *args)
zst.next_in = (Byte *)input;
err = inflateInit2(&zst, wsize);
return_error = 0;
switch(err) {
case(Z_OK):
break;
case(Z_MEM_ERROR):
PyErr_SetString(PyExc_MemoryError,
"Out of memory while decompressing data");
return_error = 1;
goto error;
default:
inflateEnd(&zst);
zlib_error(zst, err, "while preparing to decompress data");
return_error = 1;
goto error;
}
do {
if (return_error)
break;
Py_BEGIN_ALLOW_THREADS
err=inflate(&zst, Z_FINISH);
Py_END_ALLOW_THREADS
@ -295,8 +281,7 @@ PyZlib_decompress(PyObject *self, PyObject *args)
PyErr_Format(ZlibError, "Error %i while decompressing data",
err);
inflateEnd(&zst);
return_error = 1;
break;
goto error;
}
/* fall through */
case(Z_OK):
@ -304,7 +289,7 @@ PyZlib_decompress(PyObject *self, PyObject *args)
if (_PyString_Resize(&result_str, r_strlen << 1) == -1) {
inflateEnd(&zst);
result_str = NULL;
return_error = 1;
goto error;
}
zst.next_out = (unsigned char *)PyString_AsString(result_str) \
+ r_strlen;
@ -314,25 +299,24 @@ PyZlib_decompress(PyObject *self, PyObject *args)
default:
inflateEnd(&zst);
zlib_error(zst, err, "while decompressing data");
return_error = 1;
goto error;
}
} while (err != Z_STREAM_END);
if (!return_error) {
err = inflateEnd(&zst);
if (err != Z_OK) {
zlib_error(zst, err, "while finishing data decompression");
return NULL;
}
}
if (!return_error)
_PyString_Resize(&result_str, zst.total_out);
else
Py_XDECREF(result_str); /* sets result_str == NULL, if not already */
Py_DECREF(inputString);
return result_str;
error:
Py_DECREF(inputString);
Py_XDECREF(result_str);
return NULL;
}
static PyObject *
@ -363,8 +347,7 @@ PyZlib_compressobj(PyObject *selfptr, PyObject *args)
return NULL;
case(Z_STREAM_ERROR):
Py_DECREF(self);
PyErr_SetString(PyExc_ValueError,
"Invalid initialization option");
PyErr_SetString(PyExc_ValueError, "Invalid initialization option");
return NULL;
default:
zlib_error(self->zst, err, "while creating compression object");
@ -393,8 +376,7 @@ PyZlib_decompressobj(PyObject *selfptr, PyObject *args)
return (PyObject*)self;
case(Z_STREAM_ERROR):
Py_DECREF(self);
PyErr_SetString(PyExc_ValueError,
"Invalid initialization option");
PyErr_SetString(PyExc_ValueError, "Invalid initialization option");
return NULL;
case (Z_MEM_ERROR):
Py_DECREF(self);
@ -451,11 +433,11 @@ PyZlib_objcompress(compobject *self, PyObject *args)
PyObject *RetVal;
Byte *input;
unsigned long start_total_out;
int return_error;
PyObject *inputString;
if (!PyArg_ParseTuple(args, "S:compress", &inputString))
return NULL;
if (PyString_AsStringAndSize(inputString, (char**)&input, &inplen) == -1)
return NULL;
@ -476,14 +458,12 @@ PyZlib_objcompress(compobject *self, PyObject *args)
err = deflate(&(self->zst), Z_NO_FLUSH);
Py_END_ALLOW_THREADS
return_error = 0;
/* 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) {
return_error = 1;
break;
RetVal = NULL;
goto error;
}
self->zst.next_out = (unsigned char *)PyString_AsString(RetVal) \
+ length;
@ -499,29 +479,19 @@ PyZlib_objcompress(compobject *self, PyObject *args)
condition.
*/
if (!return_error) {
if (err != Z_OK && err != Z_BUF_ERROR) {
if (self->zst.msg == Z_NULL)
PyErr_Format(ZlibError, "Error %i while compressing",
err);
else
PyErr_Format(ZlibError, "Error %i while compressing: %.200s",
err, self->zst.msg);
return_error = 1;
zlib_error(self->zst, err, "while compressing");
Py_DECREF(RetVal);
RetVal = NULL;
goto error;
}
}
if (return_error)
RetVal = NULL; /* should have been handled by DECREF */
else
_PyString_Resize(&RetVal, self->zst.total_out - start_total_out);
if (_PyString_Resize(&RetVal,
self->zst.total_out - start_total_out) < 0)
RetVal = NULL;
error:
Py_DECREF(inputString);
LEAVE_ZLIB
return RetVal;
}
@ -544,7 +514,6 @@ PyZlib_objdecompress(compobject *self, PyObject *args)
PyObject *RetVal;
Byte *input;
unsigned long start_total_out;
int return_error;
PyObject * inputString;
if (!PyArg_ParseTuple(args, "S|i:decompress", &inputString, &max_length))
@ -565,7 +534,6 @@ PyZlib_objdecompress(compobject *self, PyObject *args)
return NULL;
ENTER_ZLIB
return_error = 0;
Py_INCREF(inputString);
@ -596,8 +564,8 @@ PyZlib_objdecompress(compobject *self, PyObject *args)
length = max_length;
if (_PyString_Resize(&RetVal, length) == -1) {
return_error = 1;
break;
RetVal = NULL;
goto error;
}
self->zst.next_out = (unsigned char *)PyString_AsString(RetVal) \
+ old_length;
@ -614,8 +582,11 @@ PyZlib_objdecompress(compobject *self, PyObject *args)
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;
if(!self->unconsumed_tail) {
Py_DECREF(RetVal);
RetVal = NULL;
goto error;
}
}
/* The end of the compressed data has been reached, so set the
@ -624,37 +595,29 @@ PyZlib_objdecompress(compobject *self, PyObject *args)
inflateEnd, but the old behaviour of only calling it on flush() is
preserved.
*/
if (!return_error) {
if (err == Z_STREAM_END) {
Py_XDECREF(self->unused_data); /* Free original empty string */
self->unused_data = PyString_FromStringAndSize(
(char *)self->zst.next_in, self->zst.avail_in);
if (self->unused_data == NULL) {
Py_DECREF(RetVal);
return_error = 1;
goto error;
}
/* We will only get Z_BUF_ERROR if the output buffer was full
but there wasn't more output when we tried again, so it is
not an error condition.
*/
} else if (err != Z_OK && err != Z_BUF_ERROR) {
if (self->zst.msg == Z_NULL)
PyErr_Format(ZlibError, "Error %i while decompressing",
err);
else
PyErr_Format(ZlibError, "Error %i while decompressing: %.200s",
err, self->zst.msg);
zlib_error(self->zst, err, "while decompressing");
Py_DECREF(RetVal);
return_error = 1;
}
RetVal = NULL;
goto error;
}
if (!return_error) {
_PyString_Resize(&RetVal, self->zst.total_out - start_total_out);
}
else
RetVal = NULL; /* should be handled by DECREF */
if (_PyString_Resize(&RetVal, self->zst.total_out - start_total_out) < 0)
RetVal = NULL;
error:
Py_DECREF(inputString);
LEAVE_ZLIB
@ -677,7 +640,6 @@ PyZlib_flush(compobject *self, PyObject *args)
PyObject *RetVal;
int flushmode = Z_FINISH;
unsigned long start_total_out;
int return_error;
if (!PyArg_ParseTuple(args, "|i:flush", &flushmode))
return NULL;
@ -702,14 +664,12 @@ PyZlib_flush(compobject *self, PyObject *args)
err = deflate(&(self->zst), flushmode);
Py_END_ALLOW_THREADS
return_error = 0;
/* 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) {
return_error = 1;
break;
RetVal = NULL;
goto error;
}
self->zst.next_out = (unsigned char *)PyString_AsString(RetVal) \
+ length;
@ -724,21 +684,15 @@ PyZlib_flush(compobject *self, PyObject *args)
/* If flushmode is Z_FINISH, we also have to call deflateEnd() to free
various data structures. Note we should only get Z_STREAM_END when
flushmode is Z_FINISH, but checking both for safety*/
if (!return_error) {
if (err == Z_STREAM_END && flushmode == Z_FINISH) {
err = deflateEnd(&(self->zst));
if (err != Z_OK) {
if (self->zst.msg == Z_NULL)
PyErr_Format(ZlibError, "Error %i from deflateEnd()",
err);
else
PyErr_Format(ZlibError,
"Error %i from deflateEnd(): %.200s",
err, self->zst.msg);
zlib_error(self->zst, err, "from deflateEnd()");
Py_DECREF(RetVal);
return_error = 1;
} else
RetVal = NULL;
goto error;
}
else
self->is_initialised = 0;
/* We will only get Z_BUF_ERROR if the output buffer was full
@ -746,23 +700,16 @@ PyZlib_flush(compobject *self, PyObject *args)
not an error condition.
*/
} else if (err!=Z_OK && err!=Z_BUF_ERROR) {
if (self->zst.msg == Z_NULL)
PyErr_Format(ZlibError, "Error %i while flushing",
err);
else
PyErr_Format(ZlibError, "Error %i while flushing: %.200s",
err, self->zst.msg);
zlib_error(self->zst, err, "while flushing");
Py_DECREF(RetVal);
return_error = 1;
}
RetVal = NULL;
}
if (!return_error)
_PyString_Resize(&RetVal, self->zst.total_out - start_total_out);
else
RetVal = NULL; /* should have been handled by DECREF */
if (_PyString_Resize(&RetVal, self->zst.total_out - start_total_out) < 0)
RetVal = NULL;
LEAVE_ZLIB
error:
LEAVE_ZLIB;
return RetVal;
}
@ -780,7 +727,7 @@ PyZlib_unflush(compobject *self, PyObject *args)
exceptions. This behaviour has been preserved.*/
{
int err;
PyObject * retval;
PyObject * retval = NULL;
if (!PyArg_ParseTuple(args, ""))
return NULL;
@ -788,10 +735,9 @@ PyZlib_unflush(compobject *self, PyObject *args)
ENTER_ZLIB
err = inflateEnd(&(self->zst));
if (err != Z_OK) {
if (err != Z_OK)
zlib_error(self->zst, err, "from inflateEnd()");
retval = NULL;
} else {
else {
self->is_initialised = 0;
retval = PyString_FromStringAndSize(NULL, 0);
}