b3be3d35de
replace PyPtr<'p, PyObject<'p>> with PyObject<'p> Borrowed python pointers stay &PyObject<'p>. Note: this means the internal representation of borrowed python pointers changes from "*mut PyObject" to "&*mut PyObject".
70 lines
2.8 KiB
Rust
70 lines
2.8 KiB
Rust
use std::sync::{Once, ONCE_INIT};
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use std::thread::Thread;
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use std::kinds::marker::NoSend;
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use ffi;
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use python::Python;
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static START: Once = ONCE_INIT;
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/// Prepares the use of python in a free-threaded context.
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pub fn prepare_freethreaded_python() {
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// Protect against race conditions when python is not yet initialized
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// and multiple threads concurrently call 'prepare_freethreaded_python()'.
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// Note that we do not protect against concurrent initialization of the python runtime
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// by other users of the python C API.
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START.call_once(|| unsafe {
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if ffi::Py_IsInitialized() != 0 {
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// If python is already initialized, we expect python threading to also be initialized,
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// as we can't make the existing python main thread acquire the GIL.
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assert!(ffi::PyEval_ThreadsInitialized() != 0);
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} else {
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// If python isn't initialized yet, we expect that python threading isn't initialized either.
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assert!(ffi::PyEval_ThreadsInitialized() == 0);
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// Initialize python.
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// We use Py_InitializeEx() with initsigs=0 to disable Python signal handling.
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// Signal handling depends on the notion of a 'main thread', which doesn't exist in this case.
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// Note that the 'main thread' notion in python isn't documented properly;
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// and running python without one is not officially supported.
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ffi::Py_InitializeEx(0);
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ffi::PyEval_InitThreads();
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// PyEval_InitThreads() will acquire the GIL,
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// but we don't want to hold it at this point
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// (it's not acquired in the other code paths)
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// So immediately release the GIL:
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let _thread_state = ffi::PyEval_SaveThread();
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// Note that the PyThreadState returned by PyEval_SaveThread is also held in TLS by the python runtime,
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// and will be restored by PyGILState_Ensure.
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}
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});
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}
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/// RAII type that represents an acquired GIL.
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#[must_use]
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pub struct GILGuard {
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gstate: ffi::PyGILState_STATE,
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marker: NoSend
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}
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impl Drop for GILGuard {
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fn drop(&mut self) {
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unsafe { ffi::PyGILState_Release(self.gstate) }
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}
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}
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impl GILGuard {
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/// Acquires the global interpreter lock, which allows access to the Python runtime.
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/// If the python runtime is not already initialized, this function will initialize it.
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/// Note that in this case, the python runtime will not have any main thread, and will
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/// not deliver signals like KeyboardInterrupt.
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pub fn acquire() -> GILGuard {
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::pythonrun::prepare_freethreaded_python();
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let gstate = unsafe { ffi::PyGILState_Ensure() }; // acquire GIL
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GILGuard { gstate: gstate, marker: NoSend }
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}
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pub fn python<'p>(&'p self) -> Python<'p> {
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unsafe { Python::assume_gil_acquired() }
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}
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}
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