New deserialization api

[Gor027]

Pre-review checklist

Fixes #94

This PR Integrates the new deserialization API from the Rust driver which is a WIP. It is dependent upon the execution profiles' PR #107 and can be merged only after the latter is already done. The lazy deserialization allows to also implement binder makers for decimal and duration types. The test_cassandra_types tests for these types are also enabled.

• [x] I have split my patch into logically separate commits.
• [x] All commit messages clearly explain what they change and why.
• [x] PR description sums up the changes and reasons why they should be introduced.
• [x] I have enabled appropriate tests in .github/workflows/build.yml in gtest_filter.
• [x] I have enabled appropriate tests in .github/workflows/cassandra.yml in gtest_filter.

[Gor027]

@wprzytula @Lorak-mmk Ping for review.

[Gor027]

A general idea to make the logic more type-safe (which Rust promotes): replace groups of Options with custom types that encode the logic inside themselves (their names, variants, etc.). E.g. in case of CassResultIterator, position is None iff row is None. This dependency could be represented as an enum:

pub struct CassResultIterator {
    result: Arc<CassResult>,
    curr_row_info: CassResultIteratorCurrentRowInfo,
}

enum CassResultIteratorCurrentRowInfo {
    NoRows,
    Rows {
        current_row: CassRow,
        position: usize,
    }
}

I like the idea to express the state of the fields of iterators through enums, but that will make this PR a lot more complicated. Do you mind doing this refactor in another PR? I will open an issue to not forget it.

[wprzytula]

A general idea to make the logic more type-safe (which Rust promotes): replace groups of Options with custom types that encode the logic inside themselves (their names, variants, etc.). E.g. in case of CassResultIterator, position is None iff row is None. This dependency could be represented as an enum:

pub struct CassResultIterator {
    result: Arc<CassResult>,
    curr_row_info: CassResultIteratorCurrentRowInfo,
}

enum CassResultIteratorCurrentRowInfo {
    NoRows,
    Rows {
        current_row: CassRow,
        position: usize,
    }
}

I like the idea to express the state of the fields of iterators through enums, but that will make this PR a lot more complicated. Do you mind doing this refactor in another PR? I will open an issue to not forget it.

I'd prefer to have the refactor done in this PR. You can put it in a separate commit.

[Gor027]

A general idea to make the logic more type-safe (which Rust promotes): replace groups of Options with custom types that encode the logic inside themselves (their names, variants, etc.). E.g. in case of CassResultIterator, position is None iff row is None. This dependency could be represented as an enum:

pub struct CassResultIterator {
    result: Arc<CassResult>,
    curr_row_info: CassResultIteratorCurrentRowInfo,
}

enum CassResultIteratorCurrentRowInfo {
    NoRows,
    Rows {
        current_row: CassRow,
        position: usize,
    }
}

I have applied the idea in separate commits. Perhaps this approach is more expressive and makes it easy to understand the iterator's state, although it looks overhead to me.

[Gor027]

Looking at the maze of ifs, I'm convinced that a set of unit tests for deserialization is absolutely required.

I added some relevant tests for collection iterators as Cassandra tests may not cover everything.

[Lorak-mmk]

I think we can safely close this.

[Lorak-mmk]

Oops, wrong PR

[Lorak-mmk]

After all I think we can close this - applying new deserialization to cpp-rust-driver will require at least some changes to this PR, so it will have to be done by someone else.