Skip to content

gh-132983: Convert dict_content to take Py_buffer #133924

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 6 commits into from
May 26, 2025
Merged

gh-132983: Convert dict_content to take Py_buffer #133924

Changes from 2 commits
Commits
Show all changes
6 commits
Select commit Hold shift + click to select a range
42782b8
Convert dict_content to take Py_buffer
AA-Turner May 11, 2025
7c0d002
Respond to review comments
AA-Turner May 24, 2025
30ac9d5
Respond to review comments (2)
AA-Turner May 26, 2025
e40de15
fixup! Respond to review comments (2)
AA-Turner May 26, 2025
feb034d
Improve error
AA-Turner May 26, 2025
c36f62d
delete full stop
AA-Turner May 26, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
10 changes: 5 additions & 5 deletions Modules/_zstd/zstddict.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -49,9 +49,9 @@ _zstd_ZstdDict_new_impl(PyTypeObject *type, Py_buffer *dict_content,
/* All dictionaries must be at least 8 bytes */
if (dict_content->len < 8) {
PyErr_SetString(PyExc_ValueError,
"Zstandard dictionary content should at least "
"8 bytes.");
goto error;
"Zstandard dictionary content must be longer "
"than eight bytes.");
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

It can also be exactly 8 bytes, right?

What happens if you remove this check? What error will you get?

Copy link
Member Author

@AA-Turner AA-Turner May 26, 2025 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Wording error, sorry.

What happens if you remove this check? What error will you get?

From RFC 8878 s.5, a dictionary can either be in Zstandard format or 'raw content' format.

  • "raw content" dictionaries ... must be at least 8 bytes.

  • The Zstandard format has a required 4 byte magic number and 4 byte ID

This check only bites when is_raw is True, as normally we check that the dict is a valid Zstandard directory via ZSTD_getDictID_fromDict() != 0. That function returns 0 if dictSize < 8 or otherwise if the data does not match the Zstandard header.

The Zstandard documentation is quite sparse on 'raw content' dictionaries, but I would conclude that the early error here probably doesn't hurt, and helps ensure we are conformant to the RFC.

return NULL;
}

ZstdDict* self = PyObject_GC_New(ZstdDict, type);
Expand All @@ -72,8 +72,8 @@ _zstd_ZstdDict_new_impl(PyTypeObject *type, Py_buffer *dict_content,

self->dict_buffer = PyMem_Malloc(dict_content->len);
if (!self->dict_buffer) {
Py_DECREF(self);
return PyErr_NoMemory();
PyErr_NoMemory();
goto error;
}
memcpy(self->dict_buffer, dict_content->buf, dict_content->len);
self->dict_len = dict_content->len;
Expand Down
Loading