31ab175d56
93/93 regression tests pass (+ffi-06-callback).
Mirrors the `app->onInputEvent` install pattern from
library/modules/platform/android.sx:
1. (s32) -> s32 — single primitive arg/return
2. (*void, s32) -> s32 — opaque ctx pointer + value
(the onInputEvent shape)
Side effects via two file-level globals so the test observes both
the return value AND state mutation across multiple calls:
- g_callback_hits = N proves the callback fired N times.
- g_callback_sum = sum of args proves each individual call landed
with the correct value.
The ctx-pointer variant casts `*void` back to `*s32` inside the
callback and reads through it (`p.*`), proving the pointer survives
the round-trip with no aliasing weirdness.
60 lines
2.1 KiB
Plaintext
60 lines
2.1 KiB
Plaintext
// Phase 0 baseline (PLAN-FFI.md step 0.6): sx function passed to C
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// as a function pointer; C invokes it; sx-side observable effect.
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// Mirrors the `app->onInputEvent` install pattern in
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// library/modules/platform/android.sx.
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//
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// Two arities covered:
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// 1. (s32) -> s32 — single-arg callback
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// 2. (*void, s32) -> s32 — pointer + value (onInputEvent shape)
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//
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// Plus a side-effect via a global so we can confirm the callback
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// actually fired (return value + state mutation both observable).
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#import "modules/std.sx";
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#import c {
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#source "vendors/ffi_callback/ffi_callback.c";
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};
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ffi_apply_callback :: (cb: (s32) -> s32, value: s32) -> s32 #foreign;
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ffi_apply_callback2 :: (cb: (*void, s32) -> s32, ctx: *void, v: s32) -> s32 #foreign;
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g_callback_hits : s32 = 0;
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g_callback_sum : s32 = 0;
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double_it :: (x: s32) -> s32 {
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g_callback_hits += 1;
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g_callback_sum += x;
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x * 2;
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}
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add_with_ctx :: (ctx: *void, v: s32) -> s32 {
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g_callback_hits += 1;
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// Pass a sentinel via ctx to prove the pointer arg also survives the
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// round-trip — read it back as an s32 through *s32.
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p : *s32 = xx ctx;
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p.* + v;
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}
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main :: () -> s32 {
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// ── Single-arg callback ────────────────────────────────────────
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r1 := ffi_apply_callback(double_it, 21);
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print("callback returned = {}\n", r1);
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print("hits after first call = {}\n", g_callback_hits);
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print("sum after first call = {}\n", g_callback_sum);
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// Two more calls confirm the same fn pointer keeps working.
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ffi_apply_callback(double_it, 7);
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ffi_apply_callback(double_it, 11);
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print("hits after three calls = {}\n", g_callback_hits);
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print("sum after three calls = {}\n", g_callback_sum);
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// ── Two-arg callback with opaque ctx pointer ───────────────────
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ctx_val : s32 = 100;
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r2 := ffi_apply_callback2(add_with_ctx, xx @ctx_val, 42);
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print("ctx + value = {}\n", r2);
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print("hits after ctx callback = {}\n", g_callback_hits);
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0;
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}
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