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Copy pathemscripten_trampoline.c
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92 lines (80 loc) · 2.56 KB
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#if defined(PY_CALL_TRAMPOLINE)
#include <emscripten.h> // EM_JS
#include <Python.h>
#include "pycore_runtime.h" // _PyRuntime
/**
* This is the GoogleChromeLabs approved way to feature detect type-reflection:
* https://github.com/GoogleChromeLabs/wasm-feature-detect/blob/main/src/detectors/type-reflection/index.js
*/
EM_JS(int, _PyEM_detect_type_reflection, (), {
if (!("Function" in WebAssembly)) {
return false;
}
if (WebAssembly.Function.type) {
// Node v20
Module.PyEM_CountArgs = (func) => WebAssembly.Function.type(wasmTable.get(func)).parameters.length;
} else {
// Node >= 22, v8-based browsers
Module.PyEM_CountArgs = (func) => wasmTable.get(func).type().parameters.length;
}
return true;
});
void
_Py_EmscriptenTrampoline_Init(_PyRuntimeState *runtime)
{
runtime->wasm_type_reflection_available = _PyEM_detect_type_reflection();
}
/**
* Backwards compatible trampoline works with all JS runtimes
*/
EM_JS(PyObject*,
_PyEM_TrampolineCall_JavaScript, (PyCFunctionWithKeywords func,
PyObject *arg1,
PyObject *arg2,
PyObject *arg3),
{
return wasmTable.get(func)(arg1, arg2, arg3);
}
);
/**
* In runtimes with WebAssembly type reflection, count the number of parameters
* and cast to the appropriate signature
*/
EM_JS(int, _PyEM_CountFuncParams, (PyCFunctionWithKeywords func),
{
let n = _PyEM_CountFuncParams.cache.get(func);
if (n !== undefined) {
return n;
}
n = Module.PyEM_CountArgs(func);
_PyEM_CountFuncParams.cache.set(func, n);
return n;
}
_PyEM_CountFuncParams.cache = new Map();
)
typedef PyObject* (*zero_arg)(void);
typedef PyObject* (*one_arg)(PyObject*);
typedef PyObject* (*two_arg)(PyObject*, PyObject*);
typedef PyObject* (*three_arg)(PyObject*, PyObject*, PyObject*);
PyObject*
_PyEM_TrampolineCall_Reflection(PyCFunctionWithKeywords func,
PyObject* self,
PyObject* args,
PyObject* kw)
{
switch (_PyEM_CountFuncParams(func)) {
case 0:
return ((zero_arg)func)();
case 1:
return ((one_arg)func)(self);
case 2:
return ((two_arg)func)(self, args);
case 3:
return ((three_arg)func)(self, args, kw);
default:
PyErr_SetString(PyExc_SystemError,
"Handler takes too many arguments");
return NULL;
}
}
#endif