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Add jextract module: SQLite bindings generated with jextract, FFM arenas, C strings, out-parameters, errors, upcalls, and a JMH comparison with JNI

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jextract-25 early-access build (25-jextract+2-4) on JDK 25.0.5+8 against SQLite 3.45.1: 25 functions and 13 constants
generated into 4 committed files (the whole header would be 83 files), a small Db wrapper, the four arena kinds
used wrongly on purpose, ADDRESS vs C_POINTER zero-length vs unbounded segments and the SIGSEGV from getString
on a NULL pointer, sqlite3_open out-parameter, return codes to exceptions, a sqlite3_exec upcall and the VM exit
when it throws, the JDK 25 native-access warning and --illegal-native-access=deny, library loading failures,
and a JMH benchmark of FFM vs hand-written JNI vs plain Java (indicative only: shared 2-CPU machine).

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_017ic4b6Kg9RWSTJzyz6KP9X
This commit is contained in:
asmhatre
2026-10-30 16:36:09 +00:00
co-authored by Claude Sonnet 5.5
parent 41101bea40
commit ecceaa8b32
37 changed files with 2867 additions and 0 deletions
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jextract/output/06-arenas.txt
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$ java --enable-native-access=ALL-UNNAMED -cp build/classes demo.Arenas
== confined: one owner thread
owner reads -> ok
other thread reads -> WrongThreadException: Attempted access outside owning thread
other thread closes -> WrongThreadException: Attempted access outside owning thread
read after close -> IllegalStateException: Already closed
close twice -> IllegalStateException: Already closed
== shared: any thread, one close
other thread reads -> ok
other thread closes -> ok
read after close -> IllegalStateException: Already closed
== auto: the garbage collector frees it; close() is not allowed
allocate 8 bytes -> ok
close() -> UnsupportedOperationException: Attempted to close a non-closeable session
== global: never freed; close() is not allowed
allocate 8 bytes -> ok
close() -> UnsupportedOperationException: Attempted to close a non-closeable session
== bounds: a segment knows its size
read int at offset 0 -> ok
read int at offset 4 -> IndexOutOfBoundsException: Out of bound access on segment MemorySegment{ kind: native, address: 0x7fba74666600, byteSize: 4 }; new offset = 4; new length = 4
read long at offset 0 -> IndexOutOfBoundsException: Out of bound access on segment MemorySegment{ kind: native, address: 0x7fba74666600, byteSize: 4 }; new offset = 0; new length = 8