Fix bindings compilation

[commial]

The idiomatic way to test for null arguments is to use Option<type>.

For now, bindgen "forgets" what the inner type is in the following configuration:

type X = ...;
fn (x : Option<X>) ...

An opaque Option_X will be generated.

To avoid this behavior and conserve the actual documentation, this PR:

• introduces types for X and Option<X>
• these types are duplicated, as bindgen does not introspect the Option<type alias>
• to avoid API breaks and using an Option internally, the code uses a Rust FFI guarantee: Option<X> and X are represented the same way

[commial]

ping @mtth-bfft

[mtth-bfft]

It would probably be best for documentation purposes to add a link to the underlying issue (mozilla/cbindgen#326) in the source comment, both for future understanding and so everyone can check if the issue made progress and we can clean up this workaround eventually

It's more complex with twice the number of typedefs, but I agree it's better than #[allow(clippy::fn_null_check)] . Lgtm, thanks for adding this fix ! 👍

[commial]

Thanks for the ref, I've added it to the corresponding commit message.

[github-actions]

Benchmark for 1d5032b

Click to view benchmark

Test	Base	PR	%
chunk_size_decompress_mutilfiles_random/Layers(0x0)/1024	922.5±55.89ns	980.0±87.07ns	+6.23%
chunk_size_decompress_mutilfiles_random/Layers(0x0)/1048576	105.9±5.99µs	112.4±6.07µs	+6.14%
chunk_size_decompress_mutilfiles_random/Layers(0x0)/16777216	1653.2±33.86µs	1682.1±47.48µs	+1.75%
chunk_size_decompress_mutilfiles_random/Layers(0x0)/65536	7.2±0.62µs	7.5±0.37µs	+4.17%
chunk_size_decompress_mutilfiles_random/Layers(COMPRESS)/1024	744.0±408.06µs	747.2±408.51µs	+0.43%
chunk_size_decompress_mutilfiles_random/Layers(COMPRESS)/1048576	32.8±0.06ms	33.6±0.10ms	+2.44%
chunk_size_decompress_mutilfiles_random/Layers(COMPRESS)/16777216	262.0±0.28ms	266.0±0.17ms	+1.53%
chunk_size_decompress_mutilfiles_random/Layers(COMPRESS)/65536	6.0±0.01ms	6.0±0.01ms	0.00%
chunk_size_decompress_mutilfiles_random/Layers(ENCRYPT | COMPRESS)/1024	1094.3±598.63µs	1097.7±603.24µs	+0.31%
chunk_size_decompress_mutilfiles_random/Layers(ENCRYPT | COMPRESS)/1048576	36.4±0.05ms	36.8±0.05ms	+1.10%
chunk_size_decompress_mutilfiles_random/Layers(ENCRYPT | COMPRESS)/16777216	390.3±0.33ms	395.2±0.83ms	+1.26%
chunk_size_decompress_mutilfiles_random/Layers(ENCRYPT | COMPRESS)/65536	10.2±4.89ms	10.3±4.92ms	+0.98%
chunk_size_decompress_mutilfiles_random/Layers(ENCRYPT)/1024	1112.8±322.12µs	1043.7±289.79µs	-6.21%
chunk_size_decompress_mutilfiles_random/Layers(ENCRYPT)/1048576	11.2±0.01ms	11.2±0.28ms	0.00%
chunk_size_decompress_mutilfiles_random/Layers(ENCRYPT)/16777216	161.7±0.69ms	162.2±0.16ms	+0.31%
chunk_size_decompress_mutilfiles_random/Layers(ENCRYPT)/65536	1953.3±47.87µs	1856.3±49.72µs	-4.97%
failsafe_multiple_layers_repair/Layers(0x0)/4194304	109.4±0.06ms	109.3±0.08ms	-0.09%
failsafe_multiple_layers_repair/Layers(COMPRESS)/4194304	177.2±0.13ms	176.9±0.21ms	-0.17%
failsafe_multiple_layers_repair/Layers(ENCRYPT | COMPRESS)/4194304	187.4±0.35ms	187.1±0.42ms	-0.16%
failsafe_multiple_layers_repair/Layers(ENCRYPT)/4194304	121.3±0.18ms	121.1±0.19ms	-0.16%
reader_multiple_layers_multiple_block_size/Layers(0x0)/1024	163.6±7.98ns	170.5±5.71ns	+4.22%
reader_multiple_layers_multiple_block_size/Layers(0x0)/1048576	103.4±10.10µs	106.7±8.15µs	+3.19%
reader_multiple_layers_multiple_block_size/Layers(0x0)/16777216	1695.5±40.46µs	1669.2±25.40µs	-1.55%
reader_multiple_layers_multiple_block_size/Layers(0x0)/65536	6.4±0.84µs	6.8±0.64µs	+6.25%
reader_multiple_layers_multiple_block_size/Layers(COMPRESS)/1024	1751.0±2249.17ns	1738.9±2233.44ns	-0.69%
reader_multiple_layers_multiple_block_size/Layers(COMPRESS)/1048576	131.9±2.84µs	130.6±1.78µs	-0.99%
reader_multiple_layers_multiple_block_size/Layers(COMPRESS)/16777216	197.3±0.18ms	200.6±0.26ms	+1.67%
reader_multiple_layers_multiple_block_size/Layers(COMPRESS)/65536	153.8±182.75µs	154.0±182.41µs	+0.13%
reader_multiple_layers_multiple_block_size/Layers(ENCRYPT | COMPRESS)/1024	22.3±3.71µs	21.9±3.65µs	-1.79%
reader_multiple_layers_multiple_block_size/Layers(ENCRYPT | COMPRESS)/1048576	23.1±0.03ms	22.6±0.05ms	-2.16%
reader_multiple_layers_multiple_block_size/Layers(ENCRYPT | COMPRESS)/16777216	395.7±2.04ms	392.6±0.43ms	-0.78%
reader_multiple_layers_multiple_block_size/Layers(ENCRYPT | COMPRESS)/65536	1392.7±187.19µs	1365.0±185.68µs	-1.99%
reader_multiple_layers_multiple_block_size/Layers(ENCRYPT)/1024	10.0±0.58µs	9.7±0.55µs	-3.00%
reader_multiple_layers_multiple_block_size/Layers(ENCRYPT)/1048576	10.4±0.29ms	10.1±0.29ms	-2.88%
reader_multiple_layers_multiple_block_size/Layers(ENCRYPT)/16777216	169.3±0.10ms	164.7±1.75ms	-2.72%
reader_multiple_layers_multiple_block_size/Layers(ENCRYPT)/65536	640.5±32.66µs	621.4±32.07µs	-2.98%
reader_multiple_layers_multiple_block_size_multifiles_linear/Layers(0x0)/1024	756.4±44.56ns	744.3±41.47ns	-1.60%
reader_multiple_layers_multiple_block_size_multifiles_linear/Layers(0x0)/1048576	101.9±5.81µs	104.0±2.67µs	+2.06%
reader_multiple_layers_multiple_block_size_multifiles_linear/Layers(0x0)/16777216	1672.2±41.41µs	1696.6±30.52µs	+1.46%
reader_multiple_layers_multiple_block_size_multifiles_linear/Layers(0x0)/65536	7.4±0.23µs	7.4±0.34µs	0.00%
reader_multiple_layers_multiple_block_size_multifiles_linear/Layers(COMPRESS)/1024	18.4±0.32µs	18.3±0.15µs	-0.54%
reader_multiple_layers_multiple_block_size_multifiles_linear/Layers(COMPRESS)/1048576	16.2±0.03ms	16.3±0.03ms	+0.62%
reader_multiple_layers_multiple_block_size_multifiles_linear/Layers(COMPRESS)/16777216	262.2±0.19ms	263.6±0.29ms	+0.53%
reader_multiple_layers_multiple_block_size_multifiles_linear/Layers(COMPRESS)/65536	1025.4±6.69µs	1033.0±7.06µs	+0.74%
reader_multiple_layers_multiple_block_size_multifiles_linear/Layers(ENCRYPT | COMPRESS)/1024	26.8±0.21µs	26.9±0.26µs	+0.37%
reader_multiple_layers_multiple_block_size_multifiles_linear/Layers(ENCRYPT | COMPRESS)/1048576	24.2±0.04ms	24.4±0.08ms	+0.83%
reader_multiple_layers_multiple_block_size_multifiles_linear/Layers(ENCRYPT | COMPRESS)/16777216	393.3±0.40ms	393.5±0.36ms	+0.05%
reader_multiple_layers_multiple_block_size_multifiles_linear/Layers(ENCRYPT | COMPRESS)/65536	1526.6±11.15µs	1527.1±11.00µs	+0.03%
reader_multiple_layers_multiple_block_size_multifiles_linear/Layers(ENCRYPT)/1024	11.8±0.11µs	11.6±0.11µs	-1.69%
reader_multiple_layers_multiple_block_size_multifiles_linear/Layers(ENCRYPT)/1048576	10.1±0.01ms	10.1±0.07ms	0.00%
reader_multiple_layers_multiple_block_size_multifiles_linear/Layers(ENCRYPT)/16777216	161.9±0.11ms	161.8±0.11ms	-0.06%
reader_multiple_layers_multiple_block_size_multifiles_linear/Layers(ENCRYPT)/65536	645.9±2.04µs	633.6±0.86µs	-1.90%
writer_multiple_layers_multiple_block_size/Layers(0x0)/1024	13.5±0.09µs	13.5±0.12µs	0.00%
writer_multiple_layers_multiple_block_size/Layers(0x0)/1048576	13.5±0.16ms	13.5±0.15ms	0.00%
writer_multiple_layers_multiple_block_size/Layers(0x0)/16777216	216.5±0.99ms	216.8±1.02ms	+0.14%
writer_multiple_layers_multiple_block_size/Layers(0x0)/65536	841.9±11.17µs	842.7±11.39µs	+0.10%
writer_multiple_layers_multiple_block_size/Layers(COMPRESS)/1024	21.4±0.44µs	21.6±0.51µs	+0.93%
writer_multiple_layers_multiple_block_size/Layers(COMPRESS)/1048576	26.7±1.39ms	27.0±1.45ms	+1.12%
writer_multiple_layers_multiple_block_size/Layers(COMPRESS)/16777216	666.4±2.40ms	671.8±2.33ms	+0.81%
writer_multiple_layers_multiple_block_size/Layers(COMPRESS)/65536	1326.7±29.10µs	1341.1±32.27µs	+1.09%
writer_multiple_layers_multiple_block_size/Layers(ENCRYPT | COMPRESS)/1024	21.4±0.56µs	21.5±0.54µs	+0.47%
writer_multiple_layers_multiple_block_size/Layers(ENCRYPT | COMPRESS)/1048576	28.6±1.97ms	29.1±1.89ms	+1.75%
writer_multiple_layers_multiple_block_size/Layers(ENCRYPT | COMPRESS)/16777216	791.6±2.13ms	800.3±2.52ms	+1.10%
writer_multiple_layers_multiple_block_size/Layers(ENCRYPT | COMPRESS)/65536	1331.1±26.79µs	1345.8±28.12µs	+1.10%
writer_multiple_layers_multiple_block_size/Layers(ENCRYPT)/1024	24.6±0.07µs	24.3±0.08µs	-1.22%
writer_multiple_layers_multiple_block_size/Layers(ENCRYPT)/1048576	23.9±0.09ms	23.7±0.09ms	-0.84%
writer_multiple_layers_multiple_block_size/Layers(ENCRYPT)/16777216	382.2±0.88ms	378.7±0.83ms	-0.92%
writer_multiple_layers_multiple_block_size/Layers(ENCRYPT)/65536	1489.9±7.27µs	1476.1±7.23µs	-0.93%