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Release v1.1.0

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@github-actions github-actions released this 04 Feb 21:57
v1.1.0
28e6469

Changes

Breaking Changes

  • BREAKING: read_last() return signature changed from Optional[bytes] to Tuple[Optional[bytes], int]
    • Now returns (data, size) tuple where size indicates the number of slots the item occupies
    • Migration: Change data = q.read_last() to data, size = q.read_last()
    • Provides actual slot size information instead of always returning full element_size

Added

  • Modern format support with efficient last_published_ atomic tracking
    • New last_published_ atomic field at offset 16 for O(1) read_last() performance
    • Header magic number 0x534C5131 ('SLQ1') at offset 24 for format detection
    • Init state atomic at offset 48 for CAS-based ownership detection
    • Automatic format detection distinguishes modern vs legacy queues
  • CAS-based queue ownership detection matching C++ implementation (queue.h:618-648)
  • Helper methods _wait_for_shared_memory_ready() and _detect_format_version()
  • Comprehensive test suites:
    • test_read_last.py: 10 tests covering empty queue, single/multiple items, multi-slot publishes, concurrent publishes, reset, shared memory, wraparound, variable sizes
    • test_read_last_interop.py: 5 tests for Python ↔ C++ interoperability
    • test_modern_format.py: 6 tests for format compatibility and memory layout verification
  • C++ test program cpp_read_last_tester.cpp for read_last() interoperability testing
  • New constants: SIZE_OFFSET, ELEMENT_SIZE_OFFSET, LAST_PUBLISHED_OFFSET, HEADER_MAGIC_OFFSET, HEADER_MAGIC, INIT_STATE_OFFSET, INIT_STATE_*, K_INVALID_INDEX
  • Documentation: READ_LAST_INTEROP.md comprehensive interoperability guide

Changed

  • Updated shared memory header layout to match C++ slick-queue v1.x:
    • Reserved info: 8 bytes at offset 0-7 (compact from previous 32-byte padded format)
    • Size: 4 bytes at offset 8-11 (moved from offset 32)
    • Element size: 4 bytes at offset 12-15 (moved from offset 36)
    • Last published: 8 bytes at offset 16-23 (NEW)
    • Header magic: 4 bytes at offset 24-27 (NEW)
    • Init state: 4 bytes at offset 48-51 (NEW)
  • publish() now updates last_published_ atomic using CAS loop in modern format (queue.h:331-337)
  • reset() now resets last_published_ to K_INVALID_INDEX when in modern format
  • close() properly releases _atomic_last_published wrapper
  • AtomicReservedInfo.RESERVED_INFO_FMT simplified from 32-byte to 8-byte format
  • Repository name changed from slick_queue_py to slick-queue-py
  • Updated README.md with new read_last() API documentation
  • Enhanced CMakeLists.txt with new test targets

Fixed

  • read_last() now returns actual slot size instead of always returning full element_size
  • Test queue names shortened to comply with macOS 31-character shared memory name limit

Performance

  • O(1) read_last() via direct atomic load (improved from reserved_info calculation)
  • Reduced header size: 8-byte reserved_info vs 32-byte padded (24 bytes saved)
  • Lock-free last_published_ tracking enables efficient concurrent access

Compatibility

  • Backward Compatible: Automatically detects and supports legacy queue format
  • C++ Interop: Full compatibility with C++ slick-queue modern format
  • Python and C++ can share queues created by either language
  • All existing tests continue to pass (atomic ops, cursors, local mode, multi-producer, interop)
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