deser: lazy CassRow construction #213
Draft
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
muzarski
force-pushed
the
bump-cpp-rust-cfg
branch
from
44fd342 to
d0a9ca9
Compare
muzarski
force-pushed
the
bump-cpp-rust-cfg
branch
from
d0a9ca9 to
4dfdf42
Compare
Other parts of the code make an assumption, that the pointer representing `CassDataType` was obtained from an Arc allocation. Take for example `cass_data_type_add_sub_type` - it clones an Arc. This is a bug, that was fortunately detected by applying more restrictions on the pointer types (introduced later in this PR).
The same bug as for collection types.
Again, if someone called `cass_data_type_add_sub_type` with a data type obtained from `cass_column_meta_data_type`, it would not be a pointer from an Arc allocation.
Weak::as_ptr() can return an invalid pointer. It can be even dangling (non-null). It's safer to try to upgrade to an Arc. If upgrade was successful, make use of RefFFI API to return a valid pointer. Otherwise, return non-dangling null pointer.
Before this PR, the pointer was obtained from a valid
reference &CassFuture, which is totally fine.
However, I want to reduce the ways one can obtain such pointer.
For ArcFFI (shared pointers), I want them to be obtainable only in two ways:
- `ArcFFI::as_ptr()` which accepts an &Arc
- from the user, as a function parameter
This way, we are guaranteed that the pointer comes from a valid Arc allocation
(unless user provided pointer to some garbage, but there is no much we can do about it).
If we assume that user provides a pointer returned from some prior call to
API, we are guaranteed that it is valid, and comes from an Arc allocation (or is null).
I don't want to allow ArcFFI api to create a pointer from a refernce, to prevent
creating a pointer, from example from stack allocated object:
```
let future = CassFuture { ... };
let future_ptr = ArcFFI::as_ptr(&future);
```
This commit may not make much sense now, but all should be clear once
I introduce traits restricting the pointer types later in this PR.
This commit introduces a `CassPtr` type, generic over pointer `Properties`. It allows specific pointer-to-reference conversions based on the guarantees provided by the pointer type. Existing `Ref/Box/Arc`FFIs are adjusted, so they now allow interaction with new pointer type. You can say, that for a user of `argconv` API, new type is opaque. The only way to operate on it is to use the corresponding ffi API.
Disallow implementing two different APIs for specific type.
muzarski
force-pushed
the
bump-cpp-rust-cfg
branch
from
4dfdf42 to
40cf28e
Compare
We also need to bump thiserror to 2.x. Stopped matching against `BadQuery::SerializeValuesError` as it's deprecated.
muzarski
force-pushed
the
bump-cpp-rust-cfg
branch
from
40cf28e to
da5ce8e
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Pre-review checklist
.github/workflows/build.ymlingtest_filter..github/workflows/cassandra.ymlingtest_filter.