Initializer for PyCSimple, PyCArray by youknowone · Pull Request #6581 · RustPython/RustPython

Walkthrough

This PR introduces Initializer trait implementations for PyCArray and PyCSimple ctypes, enabling reinitialization through __init__ calls with memory-aware buffer handling using Cow-based writes that update in-place for borrowed memory or fallback to owned copies.

Changes

Sequence Diagram

sequenceDiagram
    participant Python as Python Caller
    participant Init as Initializer::init()
    participant CType as PyCArray/PyCSimple
    participant Buffer as Memory Buffer
    participant Cow as Cow Handler
    
    Python->>Init: __init__(args)
    Init->>Init: Extract args from OptionalArg/tuple
    loop For each element/value
        Init->>CType: Process item
        CType->>Cow: Check buffer type (Borrowed vs Owned)
        alt Borrowed Memory
            Cow->>Buffer: Convert to mutable slice
            Buffer->>Buffer: Write in-place
        else Owned Memory
            Cow->>Buffer: Create new Owned copy
            Buffer->>Buffer: Copy and update
        end
    end
    CType-->>Python: Initialization complete

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• small fixes #6444: Modifies the Initializer slot binding and __init__ signature requirements that these trait implementations must conform to.
• ctypes overhaul #6450: Introduces parallel Initializer-based lifecycle and buffer/write changes for the same ctypes types with overlapping modifications.
• Init copyslot #6515: Changes Initializer slot codegen and registration plumbing that enables slot registration in pyclass declarations as introduced here.

Suggested reviewers

• arihant2math

Poem

🐰 hops with glee
Init blooms anew with memory's care,
Borrowed or owned buffers dance fair,
Cow rewrites what Python did call,
Arrays and simples reinit them all! ✨

• X
• Mastodon
• Reddit
• LinkedIn