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[3.14] gh-133885: Use locks instead of critical sections for _zstd (gh-134289) (gh-134560)

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Move from using critical sections to locks for the (de)compression methods.
Since the methods allow other threads to run, we should use a lock rather
than a critical section.
(cherry picked from commit 8dbc119719)

Co-authored-by: Emma Smith <emma@emmatyping.dev>
This commit is contained in:
Miss Islington (bot) 2025-05-23 12:00:38 +02:00 • committed by GitHub
parent 896b745a7a
commit 81675941fb
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
7 changed files with 229 additions and 182 deletions
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56
Lib/test/test_zstd.py
View file

@ -2430,10 +2430,8 @@ class OpenTestCase(unittest.TestCase):
self.assertEqual(f.write(arr), LENGTH)
self.assertEqual(f.tell(), LENGTH)
@unittest.skip("it fails for now, see gh-133885")
class FreeThreadingMethodTests(unittest.TestCase):
@unittest.skipUnless(Py_GIL_DISABLED, 'this test can only possibly fail with GIL disabled')
@threading_helper.reap_threads
@threading_helper.requires_working_threading()
def test_compress_locking(self):
@ -2470,7 +2468,6 @@ class FreeThreadingMethodTests(unittest.TestCase):
actual = b''.join(output) + rest2
self.assertEqual(expected, actual)
@unittest.skipUnless(Py_GIL_DISABLED, 'this test can only possibly fail with GIL disabled')
@threading_helper.reap_threads
@threading_helper.requires_working_threading()
def test_decompress_locking(self):
@ -2506,6 +2503,59 @@ class FreeThreadingMethodTests(unittest.TestCase):
actual = b''.join(output)
self.assertEqual(expected, actual)
@threading_helper.reap_threads
@threading_helper.requires_working_threading()
def test_compress_shared_dict(self):
num_threads = 8
def run_method(b):
level = threading.get_ident() % 4
# sync threads to increase chance of contention on
# capsule storing dictionary levels
b.wait()
ZstdCompressor(level=level,
zstd_dict=TRAINED_DICT.as_digested_dict)
b.wait()
ZstdCompressor(level=level,
zstd_dict=TRAINED_DICT.as_undigested_dict)
b.wait()
ZstdCompressor(level=level,
zstd_dict=TRAINED_DICT.as_prefix)
threads = []
b = threading.Barrier(num_threads)
for i in range(num_threads):
thread = threading.Thread(target=run_method, args=(b,))
threads.append(thread)
with threading_helper.start_threads(threads):
pass
@threading_helper.reap_threads
@threading_helper.requires_working_threading()
def test_decompress_shared_dict(self):
num_threads = 8
def run_method(b):
# sync threads to increase chance of contention on
# decompression dictionary
b.wait()
ZstdDecompressor(zstd_dict=TRAINED_DICT.as_digested_dict)
b.wait()
ZstdDecompressor(zstd_dict=TRAINED_DICT.as_undigested_dict)
b.wait()
ZstdDecompressor(zstd_dict=TRAINED_DICT.as_prefix)
threads = []
b = threading.Barrier(num_threads)
for i in range(num_threads):
thread = threading.Thread(target=run_method, args=(b,))
threads.append(thread)
with threading_helper.start_threads(threads):
pass
if __name__ == "__main__":

11
Modules/_zstd/clinic/decompressor.c.h generated
View file

@ -7,7 +7,6 @@ preserve
# include "pycore_runtime.h" // _Py_ID()
#endif
#include "pycore_abstract.h" // _PyNumber_Index()
#include "pycore_critical_section.h"// Py_BEGIN_CRITICAL_SECTION()
#include "pycore_modsupport.h" // _PyArg_UnpackKeywords()
PyDoc_STRVAR(_zstd_ZstdDecompressor_new__doc__,
@ -114,13 +113,7 @@ _zstd_ZstdDecompressor_unused_data_get_impl(ZstdDecompressor *self);
static PyObject *
_zstd_ZstdDecompressor_unused_data_get(PyObject *self, void *Py_UNUSED(context))
{
PyObject *return_value = NULL;
Py_BEGIN_CRITICAL_SECTION(self);
return_value = _zstd_ZstdDecompressor_unused_data_get_impl((ZstdDecompressor *)self);
Py_END_CRITICAL_SECTION();
return return_value;
return _zstd_ZstdDecompressor_unused_data_get_impl((ZstdDecompressor *)self);
}
PyDoc_STRVAR(_zstd_ZstdDecompressor_decompress__doc__,
@ -227,4 +220,4 @@ exit:
return return_value;
}
/*[clinic end generated code: output=7a4d278f9244e684 input=a9049054013a1b77]*/
/*[clinic end generated code: output=30c12ef047027ede input=a9049054013a1b77]*/

27
Modules/_zstd/clinic/zstddict.c.h generated
View file

@ -6,7 +6,6 @@ preserve
# include "pycore_gc.h" // PyGC_Head
# include "pycore_runtime.h" // _Py_ID()
#endif
#include "pycore_critical_section.h"// Py_BEGIN_CRITICAL_SECTION()
#include "pycore_modsupport.h" // _PyArg_UnpackKeywords()
PyDoc_STRVAR(_zstd_ZstdDict_new__doc__,
@ -118,13 +117,7 @@ _zstd_ZstdDict_as_digested_dict_get_impl(ZstdDict *self);
static PyObject *
_zstd_ZstdDict_as_digested_dict_get(PyObject *self, void *Py_UNUSED(context))
{
PyObject *return_value = NULL;
Py_BEGIN_CRITICAL_SECTION(self);
return_value = _zstd_ZstdDict_as_digested_dict_get_impl((ZstdDict *)self);
Py_END_CRITICAL_SECTION();
return return_value;
return _zstd_ZstdDict_as_digested_dict_get_impl((ZstdDict *)self);
}
PyDoc_STRVAR(_zstd_ZstdDict_as_undigested_dict__doc__,
@ -156,13 +149,7 @@ _zstd_ZstdDict_as_undigested_dict_get_impl(ZstdDict *self);
static PyObject *
_zstd_ZstdDict_as_undigested_dict_get(PyObject *self, void *Py_UNUSED(context))
{
PyObject *return_value = NULL;
Py_BEGIN_CRITICAL_SECTION(self);
return_value = _zstd_ZstdDict_as_undigested_dict_get_impl((ZstdDict *)self);
Py_END_CRITICAL_SECTION();
return return_value;
return _zstd_ZstdDict_as_undigested_dict_get_impl((ZstdDict *)self);
}
PyDoc_STRVAR(_zstd_ZstdDict_as_prefix__doc__,
@ -194,12 +181,6 @@ _zstd_ZstdDict_as_prefix_get_impl(ZstdDict *self);
static PyObject *
_zstd_ZstdDict_as_prefix_get(PyObject *self, void *Py_UNUSED(context))
{
PyObject *return_value = NULL;
Py_BEGIN_CRITICAL_SECTION(self);
return_value = _zstd_ZstdDict_as_prefix_get_impl((ZstdDict *)self);
Py_END_CRITICAL_SECTION();
return return_value;
return _zstd_ZstdDict_as_prefix_get_impl((ZstdDict *)self);
}
/*[clinic end generated code: output=bfb31c1187477afd input=a9049054013a1b77]*/
/*[clinic end generated code: output=8692eabee4e0d1fe input=a9049054013a1b77]*/

147
Modules/_zstd/compressor.c
View file

@ -17,6 +17,7 @@ class _zstd.ZstdCompressor "ZstdCompressor *" "&zstd_compressor_type_spec"
#include "_zstdmodule.h"
#include "buffer.h"
#include "zstddict.h"
#include "internal/pycore_lock.h" // PyMutex_IsLocked
#include <stddef.h> // offsetof()
#include <zstd.h> // ZSTD_*()
@ -38,6 +39,9 @@ typedef struct {
/* Compression level */
int compression_level;
/* Lock to protect the compression context */
PyMutex lock;
} ZstdCompressor;
#define ZstdCompressor_CAST(op) ((ZstdCompressor *)op)
@ -149,12 +153,12 @@ capsule_free_cdict(PyObject *capsule)
ZSTD_CDict *
_get_CDict(ZstdDict *self, int compressionLevel)
{
assert(PyMutex_IsLocked(&self->lock));
PyObject *level = NULL;
PyObject *capsule;
PyObject *capsule = NULL;
ZSTD_CDict *cdict;
int ret;
// TODO(emmatyping): refactor critical section code into a lock_held function
Py_BEGIN_CRITICAL_SECTION(self);
/* int level object */
level = PyLong_FromLong(compressionLevel);
@ -163,12 +167,11 @@ _get_CDict(ZstdDict *self, int compressionLevel)
}
/* Get PyCapsule object from self->c_dicts */
capsule = PyDict_GetItemWithError(self->c_dicts, level);
if (capsule == NULL) {
if (PyErr_Occurred()) {
ret = PyDict_GetItemRef(self->c_dicts, level, &capsule);
if (ret < 0) {
goto error;
}
if (capsule == NULL) {
/* Create ZSTD_CDict instance */
char *dict_buffer = PyBytes_AS_STRING(self->dict_content);
Py_ssize_t dict_len = Py_SIZE(self->dict_content);
@ -196,11 +199,10 @@ _get_CDict(ZstdDict *self, int compressionLevel)
}
/* Add PyCapsule object to self->c_dicts */
if (PyDict_SetItem(self->c_dicts, level, capsule) < 0) {
Py_DECREF(capsule);
ret = PyDict_SetItem(self->c_dicts, level, capsule);
if (ret < 0) {
goto error;
}
Py_DECREF(capsule);
}
else {
/* ZSTD_CDict instance already exists */
@ -212,15 +214,55 @@ error:
cdict = NULL;
success:
Py_XDECREF(level);
Py_END_CRITICAL_SECTION();
Py_XDECREF(capsule);
return cdict;
}
static int
_zstd_load_impl(ZstdCompressor *self, ZstdDict *zd,
_zstd_state *mod_state, int type)
{
size_t zstd_ret;
if (type == DICT_TYPE_DIGESTED) {
/* Get ZSTD_CDict */
ZSTD_CDict *c_dict = _get_CDict(zd, self->compression_level);
if (c_dict == NULL) {
return -1;
}
/* Reference a prepared dictionary.
It overrides some compression context's parameters. */
zstd_ret = ZSTD_CCtx_refCDict(self->cctx, c_dict);
}
else if (type == DICT_TYPE_UNDIGESTED) {
/* Load a dictionary.
It doesn't override compression context's parameters. */
zstd_ret = ZSTD_CCtx_loadDictionary(
self->cctx,
PyBytes_AS_STRING(zd->dict_content),
Py_SIZE(zd->dict_content));
}
else if (type == DICT_TYPE_PREFIX) {
/* Load a prefix */
zstd_ret = ZSTD_CCtx_refPrefix(
self->cctx,
PyBytes_AS_STRING(zd->dict_content),
Py_SIZE(zd->dict_content));
}
else {
Py_UNREACHABLE();
}
/* Check error */
if (ZSTD_isError(zstd_ret)) {
set_zstd_error(mod_state, ERR_LOAD_C_DICT, zstd_ret);
return -1;
}
return 0;
}
static int
_zstd_load_c_dict(ZstdCompressor *self, PyObject *dict)
{
size_t zstd_ret;
_zstd_state* const mod_state = PyType_GetModuleState(Py_TYPE(self));
if (mod_state == NULL) {
return -1;
@ -237,7 +279,10 @@ _zstd_load_c_dict(ZstdCompressor *self, PyObject *dict)
/* When compressing, use undigested dictionary by default. */
zd = (ZstdDict*)dict;
type = DICT_TYPE_UNDIGESTED;
goto load;
PyMutex_Lock(&zd->lock);
ret = _zstd_load_impl(self, zd, mod_state, type);
PyMutex_Unlock(&zd->lock);
return ret;
}
/* Check (ZstdDict, type) */
@ -257,7 +302,10 @@ _zstd_load_c_dict(ZstdCompressor *self, PyObject *dict)
{
assert(type >= 0);
zd = (ZstdDict*)PyTuple_GET_ITEM(dict, 0);
goto load;
PyMutex_Lock(&zd->lock);
ret = _zstd_load_impl(self, zd, mod_state, type);
PyMutex_Unlock(&zd->lock);
return ret;
}
}
}
@ -266,49 +314,6 @@ _zstd_load_c_dict(ZstdCompressor *self, PyObject *dict)
PyErr_SetString(PyExc_TypeError,
"zstd_dict argument should be ZstdDict object.");
return -1;
load:
if (type == DICT_TYPE_DIGESTED) {
/* Get ZSTD_CDict */
ZSTD_CDict *c_dict = _get_CDict(zd, self->compression_level);
if (c_dict == NULL) {
return -1;
}
/* Reference a prepared dictionary.
It overrides some compression context's parameters. */
Py_BEGIN_CRITICAL_SECTION(self);
zstd_ret = ZSTD_CCtx_refCDict(self->cctx, c_dict);
Py_END_CRITICAL_SECTION();
}
else if (type == DICT_TYPE_UNDIGESTED) {
/* Load a dictionary.
It doesn't override compression context's parameters. */
Py_BEGIN_CRITICAL_SECTION2(self, zd);
zstd_ret = ZSTD_CCtx_loadDictionary(
self->cctx,
PyBytes_AS_STRING(zd->dict_content),
Py_SIZE(zd->dict_content));
Py_END_CRITICAL_SECTION2();
}
else if (type == DICT_TYPE_PREFIX) {
/* Load a prefix */
Py_BEGIN_CRITICAL_SECTION2(self, zd);
zstd_ret = ZSTD_CCtx_refPrefix(
self->cctx,
PyBytes_AS_STRING(zd->dict_content),
Py_SIZE(zd->dict_content));
Py_END_CRITICAL_SECTION2();
}
else {
Py_UNREACHABLE();
}
/* Check error */
if (ZSTD_isError(zstd_ret)) {
set_zstd_error(mod_state, ERR_LOAD_C_DICT, zstd_ret);
return -1;
}
return 0;
}
/*[clinic input]
@ -339,6 +344,7 @@ _zstd_ZstdCompressor_new_impl(PyTypeObject *type, PyObject *level,
self->use_multithread = 0;
self->dict = NULL;
self->lock = (PyMutex){0};
/* Compression context */
self->cctx = ZSTD_createCCtx();
@ -403,6 +409,8 @@ ZstdCompressor_dealloc(PyObject *ob)
ZSTD_freeCCtx(self->cctx);
}
assert(!PyMutex_IsLocked(&self->lock));
/* Py_XDECREF the dict after free the compression context */
Py_CLEAR(self->dict);
@ -412,9 +420,10 @@ ZstdCompressor_dealloc(PyObject *ob)
}
static PyObject *
compress_impl(ZstdCompressor *self, Py_buffer *data,
compress_lock_held(ZstdCompressor *self, Py_buffer *data,
ZSTD_EndDirective end_directive)
{
assert(PyMutex_IsLocked(&self->lock));
ZSTD_inBuffer in;
ZSTD_outBuffer out;
_BlocksOutputBuffer buffer = {.list = NULL};
@ -495,8 +504,9 @@ mt_continue_should_break(ZSTD_inBuffer *in, ZSTD_outBuffer *out)
#endif
static PyObject *
compress_mt_continue_impl(ZstdCompressor *self, Py_buffer *data)
compress_mt_continue_lock_held(ZstdCompressor *self, Py_buffer *data)
{
assert(PyMutex_IsLocked(&self->lock));
ZSTD_inBuffer in;
ZSTD_outBuffer out;
_BlocksOutputBuffer buffer = {.list = NULL};
@ -529,7 +539,7 @@ compress_mt_continue_impl(ZstdCompressor *self, Py_buffer *data)
goto error;
}
/* Like compress_impl(), output as much as possible. */
/* Like compress_lock_held(), output as much as possible. */
if (out.pos == out.size) {
if (_OutputBuffer_Grow(&buffer, &out) < 0) {
goto error;
@ -588,14 +598,14 @@ _zstd_ZstdCompressor_compress_impl(ZstdCompressor *self, Py_buffer *data,
}
/* Thread-safe code */
Py_BEGIN_CRITICAL_SECTION(self);
PyMutex_Lock(&self->lock);
/* Compress */
if (self->use_multithread && mode == ZSTD_e_continue) {
ret = compress_mt_continue_impl(self, data);
ret = compress_mt_continue_lock_held(self, data);
}
else {
ret = compress_impl(self, data, mode);
ret = compress_lock_held(self, data, mode);
}
if (ret) {
@ -607,7 +617,7 @@ _zstd_ZstdCompressor_compress_impl(ZstdCompressor *self, Py_buffer *data,
/* Resetting cctx's session never fail */
ZSTD_CCtx_reset(self->cctx, ZSTD_reset_session_only);
}
Py_END_CRITICAL_SECTION();
PyMutex_Unlock(&self->lock);
return ret;
}
@ -642,8 +652,9 @@ _zstd_ZstdCompressor_flush_impl(ZstdCompressor *self, int mode)
}
/* Thread-safe code */
Py_BEGIN_CRITICAL_SECTION(self);
ret = compress_impl(self, NULL, mode);
PyMutex_Lock(&self->lock);
ret = compress_lock_held(self, NULL, mode);
if (ret) {
self->last_mode = mode;
@ -654,7 +665,7 @@ _zstd_ZstdCompressor_flush_impl(ZstdCompressor *self, int mode)
/* Resetting cctx's session never fail */
ZSTD_CCtx_reset(self->cctx, ZSTD_reset_session_only);
}
Py_END_CRITICAL_SECTION();
PyMutex_Unlock(&self->lock);
return ret;
}

148
Modules/_zstd/decompressor.c
View file

@ -17,6 +17,7 @@ class _zstd.ZstdDecompressor "ZstdDecompressor *" "&zstd_decompressor_type_spec"
#include "_zstdmodule.h"
#include "buffer.h"
#include "zstddict.h"
#include "internal/pycore_lock.h" // PyMutex_IsLocked
#include <stdbool.h> // bool
#include <stddef.h> // offsetof()
@ -45,6 +46,9 @@ typedef struct {
/* For ZstdDecompressor, 0 or 1.
1 means the end of the first frame has been reached. */
bool eof;
/* Lock to protect the decompression context */
PyMutex lock;
} ZstdDecompressor;
#define ZstdDecompressor_CAST(op) ((ZstdDecompressor *)op)
@ -54,6 +58,7 @@ typedef struct {
static inline ZSTD_DDict *
_get_DDict(ZstdDict *self)
{
assert(PyMutex_IsLocked(&self->lock));
ZSTD_DDict *ret;
/* Already created */
@ -61,15 +66,14 @@ _get_DDict(ZstdDict *self)
return self->d_dict;
}
Py_BEGIN_CRITICAL_SECTION(self);
if (self->d_dict == NULL) {
/* Create ZSTD_DDict instance from dictionary content */
char *dict_buffer = PyBytes_AS_STRING(self->dict_content);
Py_ssize_t dict_len = Py_SIZE(self->dict_content);
Py_BEGIN_ALLOW_THREADS
self->d_dict = ZSTD_createDDict(dict_buffer,
dict_len);
ret = ZSTD_createDDict(dict_buffer, dict_len);
Py_END_ALLOW_THREADS
self->d_dict = ret;
if (self->d_dict == NULL) {
_zstd_state* const mod_state = PyType_GetModuleState(Py_TYPE(self));
@ -81,11 +85,7 @@ _get_DDict(ZstdDict *self)
}
}
/* Don't lose any exception */
ret = self->d_dict;
Py_END_CRITICAL_SECTION();
return ret;
return self->d_dict;
}
/* Set decompression parameters to decompression context */
@ -134,9 +134,7 @@ _zstd_set_d_parameters(ZstdDecompressor *self, PyObject *options)
}
/* Set parameter to compression context */
Py_BEGIN_CRITICAL_SECTION(self);
zstd_ret = ZSTD_DCtx_setParameter(self->dctx, key_v, value_v);
Py_END_CRITICAL_SECTION();
/* Check error */
if (ZSTD_isError(zstd_ret)) {
@ -147,11 +145,53 @@ _zstd_set_d_parameters(ZstdDecompressor *self, PyObject *options)
return 0;
}
static int
_zstd_load_impl(ZstdDecompressor *self, ZstdDict *zd,
_zstd_state *mod_state, int type)
{
size_t zstd_ret;
if (type == DICT_TYPE_DIGESTED) {
/* Get ZSTD_DDict */
ZSTD_DDict *d_dict = _get_DDict(zd);
if (d_dict == NULL) {
return -1;
}
/* Reference a prepared dictionary */
zstd_ret = ZSTD_DCtx_refDDict(self->dctx, d_dict);
}
else if (type == DICT_TYPE_UNDIGESTED) {
/* Load a dictionary */
zstd_ret = ZSTD_DCtx_loadDictionary(
self->dctx,
PyBytes_AS_STRING(zd->dict_content),
Py_SIZE(zd->dict_content));
}
else if (type == DICT_TYPE_PREFIX) {
/* Load a prefix */
zstd_ret = ZSTD_DCtx_refPrefix(
self->dctx,
PyBytes_AS_STRING(zd->dict_content),
Py_SIZE(zd->dict_content));
}
else {
/* Impossible code path */
PyErr_SetString(PyExc_SystemError,
"load_d_dict() impossible code path");
return -1;
}
/* Check error */
if (ZSTD_isError(zstd_ret)) {
set_zstd_error(mod_state, ERR_LOAD_D_DICT, zstd_ret);
return -1;
}
return 0;
}
/* Load dictionary or prefix to decompression context */
static int
_zstd_load_d_dict(ZstdDecompressor *self, PyObject *dict)
{
size_t zstd_ret;
_zstd_state* const mod_state = PyType_GetModuleState(Py_TYPE(self));
if (mod_state == NULL) {
return -1;
@ -168,7 +208,10 @@ _zstd_load_d_dict(ZstdDecompressor *self, PyObject *dict)
/* When decompressing, use digested dictionary by default. */
zd = (ZstdDict*)dict;
type = DICT_TYPE_DIGESTED;
goto load;
PyMutex_Lock(&zd->lock);
ret = _zstd_load_impl(self, zd, mod_state, type);
PyMutex_Unlock(&zd->lock);
return ret;
}
/* Check (ZstdDict, type) */
@ -188,7 +231,10 @@ _zstd_load_d_dict(ZstdDecompressor *self, PyObject *dict)
{
assert(type >= 0);
zd = (ZstdDict*)PyTuple_GET_ITEM(dict, 0);
goto load;
PyMutex_Lock(&zd->lock);
ret = _zstd_load_impl(self, zd, mod_state, type);
PyMutex_Unlock(&zd->lock);
return ret;
}
}
}
@ -197,50 +243,6 @@ _zstd_load_d_dict(ZstdDecompressor *self, PyObject *dict)
PyErr_SetString(PyExc_TypeError,
"zstd_dict argument should be ZstdDict object.");
return -1;
load:
if (type == DICT_TYPE_DIGESTED) {
/* Get ZSTD_DDict */
ZSTD_DDict *d_dict = _get_DDict(zd);
if (d_dict == NULL) {
return -1;
}
/* Reference a prepared dictionary */
Py_BEGIN_CRITICAL_SECTION(self);
zstd_ret = ZSTD_DCtx_refDDict(self->dctx, d_dict);
Py_END_CRITICAL_SECTION();
}
else if (type == DICT_TYPE_UNDIGESTED) {
/* Load a dictionary */
Py_BEGIN_CRITICAL_SECTION2(self, zd);
zstd_ret = ZSTD_DCtx_loadDictionary(
self->dctx,
PyBytes_AS_STRING(zd->dict_content),
Py_SIZE(zd->dict_content));
Py_END_CRITICAL_SECTION2();
}
else if (type == DICT_TYPE_PREFIX) {
/* Load a prefix */
Py_BEGIN_CRITICAL_SECTION2(self, zd);
zstd_ret = ZSTD_DCtx_refPrefix(
self->dctx,
PyBytes_AS_STRING(zd->dict_content),
Py_SIZE(zd->dict_content));
Py_END_CRITICAL_SECTION2();
}
else {
/* Impossible code path */
PyErr_SetString(PyExc_SystemError,
"load_d_dict() impossible code path");
return -1;
}
/* Check error */
if (ZSTD_isError(zstd_ret)) {
set_zstd_error(mod_state, ERR_LOAD_D_DICT, zstd_ret);
return -1;
}
return 0;
}
/*
@ -268,7 +270,7 @@ load:
Note, decompressing "an empty input" in any case will make it > 0.
*/
static PyObject *
decompress_impl(ZstdDecompressor *self, ZSTD_inBuffer *in,
decompress_lock_held(ZstdDecompressor *self, ZSTD_inBuffer *in,
Py_ssize_t max_length)
{
size_t zstd_ret;
@ -339,10 +341,9 @@ error:
}
static void
decompressor_reset_session(ZstdDecompressor *self)
decompressor_reset_session_lock_held(ZstdDecompressor *self)
{
// TODO(emmatyping): use _Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED here
// and ensure lock is always held
assert(PyMutex_IsLocked(&self->lock));
/* Reset variables */
self->in_begin = 0;
@ -359,8 +360,10 @@ decompressor_reset_session(ZstdDecompressor *self)
}
static PyObject *
stream_decompress(ZstdDecompressor *self, Py_buffer *data, Py_ssize_t max_length)
stream_decompress_lock_held(ZstdDecompressor *self, Py_buffer *data,
Py_ssize_t max_length)
{
assert(PyMutex_IsLocked(&self->lock));
ZSTD_inBuffer in;
PyObject *ret = NULL;
int use_input_buffer;
@ -456,7 +459,7 @@ stream_decompress(ZstdDecompressor *self, Py_buffer *data, Py_ssize_t max_length
assert(in.pos == 0);
/* Decompress */
ret = decompress_impl(self, &in, max_length);
ret = decompress_lock_held(self, &in, max_length);
if (ret == NULL) {
goto error;
}
@ -517,7 +520,7 @@ stream_decompress(ZstdDecompressor *self, Py_buffer *data, Py_ssize_t max_length
error:
/* Reset decompressor's states/session */
decompressor_reset_session(self);
decompressor_reset_session_lock_held(self);
Py_CLEAR(ret);
return NULL;
@ -555,6 +558,7 @@ _zstd_ZstdDecompressor_new_impl(PyTypeObject *type, PyObject *zstd_dict,
self->unused_data = NULL;
self->eof = 0;
self->dict = NULL;
self->lock = (PyMutex){0};
/* needs_input flag */
self->needs_input = 1;
@ -608,6 +612,8 @@ ZstdDecompressor_dealloc(PyObject *ob)
ZSTD_freeDCtx(self->dctx);
}
assert(!PyMutex_IsLocked(&self->lock));
/* Py_CLEAR the dict after free decompression context */
Py_CLEAR(self->dict);
@ -623,7 +629,6 @@ ZstdDecompressor_dealloc(PyObject *ob)
}
/*[clinic input]
@critical_section
@getter
_zstd.ZstdDecompressor.unused_data
@ -635,11 +640,14 @@ decompressed, unused input data after the frame. Otherwise this will be b''.
static PyObject *
_zstd_ZstdDecompressor_unused_data_get_impl(ZstdDecompressor *self)
/*[clinic end generated code: output=f3a20940f11b6b09 input=5233800bef00df04]*/
/*[clinic end generated code: output=f3a20940f11b6b09 input=54d41ecd681a3444]*/
{
PyObject *ret;
PyMutex_Lock(&self->lock);
if (!self->eof) {
PyMutex_Unlock(&self->lock);
return Py_GetConstant(Py_CONSTANT_EMPTY_BYTES);
}
else {
@ -656,6 +664,7 @@ _zstd_ZstdDecompressor_unused_data_get_impl(ZstdDecompressor *self)
}
}
PyMutex_Unlock(&self->lock);
return ret;
}
@ -693,10 +702,9 @@ _zstd_ZstdDecompressor_decompress_impl(ZstdDecompressor *self,
{
PyObject *ret;
/* Thread-safe code */
Py_BEGIN_CRITICAL_SECTION(self);
ret = stream_decompress(self, data, max_length);
Py_END_CRITICAL_SECTION();
PyMutex_Lock(&self->lock);
ret = stream_decompress_lock_held(self, data, max_length);
PyMutex_Unlock(&self->lock);
return ret;
}

13
Modules/_zstd/zstddict.c
View file

@ -17,6 +17,7 @@ class _zstd.ZstdDict "ZstdDict *" "&zstd_dict_type_spec"
#include "_zstdmodule.h"
#include "zstddict.h"
#include "clinic/zstddict.c.h"
#include "internal/pycore_lock.h" // PyMutex_IsLocked
#include <zstd.h> // ZSTD_freeDDict(), ZSTD_getDictID_fromDict()
@ -53,6 +54,7 @@ _zstd_ZstdDict_new_impl(PyTypeObject *type, PyObject *dict_content,
self->dict_content = NULL;
self->d_dict = NULL;
self->dict_id = 0;
self->lock = (PyMutex){0};
/* ZSTD_CDict dict */
self->c_dicts = PyDict_New();
@ -109,6 +111,8 @@ ZstdDict_dealloc(PyObject *ob)
ZSTD_freeDDict(self->d_dict);
}
assert(!PyMutex_IsLocked(&self->lock));
/* Release dict_content after Free ZSTD_CDict/ZSTD_DDict instances */
Py_CLEAR(self->dict_content);
Py_CLEAR(self->c_dicts);
@ -143,7 +147,6 @@ static PyMemberDef ZstdDict_members[] = {
};
/*[clinic input]
@critical_section
@getter
_zstd.ZstdDict.as_digested_dict
@ -160,13 +163,12 @@ Pass this attribute as zstd_dict argument: compress(dat, zstd_dict=zd.as_digeste
static PyObject *
_zstd_ZstdDict_as_digested_dict_get_impl(ZstdDict *self)
/*[clinic end generated code: output=09b086e7a7320dbb input=585448c79f31f74a]*/
/*[clinic end generated code: output=09b086e7a7320dbb input=10cd2b6165931b77]*/
{
return Py_BuildValue("Oi", self, DICT_TYPE_DIGESTED);
}
/*[clinic input]
@critical_section
@getter
_zstd.ZstdDict.as_undigested_dict
@ -181,13 +183,12 @@ Pass this attribute as zstd_dict argument: compress(dat, zstd_dict=zd.as_undiges
static PyObject *
_zstd_ZstdDict_as_undigested_dict_get_impl(ZstdDict *self)
/*[clinic end generated code: output=43c7a989e6d4253a input=022b0829ffb1c220]*/
/*[clinic end generated code: output=43c7a989e6d4253a input=11e5f5df690a85b4]*/
{
return Py_BuildValue("Oi", self, DICT_TYPE_UNDIGESTED);
}
/*[clinic input]
@critical_section
@getter
_zstd.ZstdDict.as_prefix
@ -202,7 +203,7 @@ Pass this attribute as zstd_dict argument: compress(dat, zstd_dict=zd.as_prefix)
static PyObject *
_zstd_ZstdDict_as_prefix_get_impl(ZstdDict *self)
/*[clinic end generated code: output=6f7130c356595a16 input=09fb82a6a5407e87]*/
/*[clinic end generated code: output=6f7130c356595a16 input=b028e0ae6ec4292b]*/
{
return Py_BuildValue("Oi", self, DICT_TYPE_PREFIX);
}

3
Modules/_zstd/zstddict.h
View file

@ -19,6 +19,9 @@ typedef struct {
PyObject *dict_content;
/* Dictionary id */
uint32_t dict_id;
/* Lock to protect the digested dictionaries */
PyMutex lock;
} ZstdDict;
#endif // !ZSTD_DICT_H