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7ae4749d06
This is useful for implementing proper `input()`. It requires the JavaScript engine to support the wasm JSPI spec which is now stage 4. It is supported on Chrome since version 137 and on Firefox and node behind a flag. We override the `__wasi_fd_read()` syscall with our own variant that checks for a readAsync operation. If it has it, we use our own async variant of `fd_read()`, otherwise we use the original `fd_read()`. We also add a variant of `FS.createDevice()` called `FS.createAsyncInputDevice()`. Finally, if JSPI is available, we wrap the `main()` symbol with `WebAssembly.promising()` so that we can stack switch from `fd_read()`. If JSPI is not available, attempting to read from an AsyncInputDevice will raise an `OSError`.
25 lines
849 B
Python
25 lines
849 B
Python
import unittest
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from test.support import is_emscripten
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if not is_emscripten:
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raise unittest.SkipTest("Emscripten-only test")
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from _testinternalcapi import emscripten_set_up_async_input_device
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from pathlib import Path
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class EmscriptenAsyncInputDeviceTest(unittest.TestCase):
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def test_emscripten_async_input_device(self):
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jspi_supported = emscripten_set_up_async_input_device()
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p = Path("/dev/blah")
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self.addCleanup(p.unlink)
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if not jspi_supported:
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with open(p, "r") as f:
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self.assertRaises(OSError, f.readline)
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return
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with open(p, "r") as f:
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for _ in range(10):
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self.assertEqual(f.readline().strip(), "ab")
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self.assertEqual(f.readline().strip(), "fi")
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self.assertEqual(f.readline().strip(), "xy")
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