two version of R2R are here HEAD master

1 files changed, 258 insertions, 0 deletions

diff --git a/.venv/lib/python3.12/site-packages/greenlet/TThreadStateDestroy.cpp b/.venv/lib/python3.12/site-packages/greenlet/TThreadStateDestroy.cpp
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+++ b/.venv/lib/python3.12/site-packages/greenlet/TThreadStateDestroy.cpp
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+/* -*- indent-tabs-mode: nil; tab-width: 4; -*- */
+/**
+ * Implementation of the ThreadState destructors.
+ *
+ * Format with:
+ *  clang-format -i --style=file src/greenlet/greenlet.c
+ *
+ *
+ * Fix missing braces with:
+ *   clang-tidy src/greenlet/greenlet.c -fix -checks="readability-braces-around-statements"
+*/
+#ifndef T_THREADSTATE_DESTROY
+#define T_THREADSTATE_DESTROY
+
+#include "TGreenlet.hpp"
+
+#include "greenlet_thread_support.hpp"
+#include "greenlet_cpython_add_pending.hpp"
+#include "greenlet_compiler_compat.hpp"
+#include "TGreenletGlobals.cpp"
+#include "TThreadState.hpp"
+#include "TThreadStateCreator.hpp"
+
+namespace greenlet {
+
+extern "C" {
+
+struct ThreadState_DestroyNoGIL
+{
+    /**
+       This function uses the same lock that the PendingCallback does
+     */
+    static void
+    MarkGreenletDeadAndQueueCleanup(ThreadState* const state)
+    {
+#if GREENLET_BROKEN_THREAD_LOCAL_CLEANUP_JUST_LEAK
+        return;
+#endif
+        // We are *NOT* holding the GIL. Our thread is in the middle
+        // of its death throes and the Python thread state is already
+        // gone so we can't use most Python APIs. One that is safe is
+        // ``Py_AddPendingCall``, unless the interpreter itself has
+        // been torn down. There is a limited number of calls that can
+        // be queued: 32 (NPENDINGCALLS) in CPython 3.10, so we
+        // coalesce these calls using our own queue.
+
+        if (!MarkGreenletDeadIfNeeded(state)) {
+            // No state, or no greenlet
+            return;
+        }
+
+        // XXX: Because we don't have the GIL, this is a race condition.
+        if (!PyInterpreterState_Head()) {
+            // We have to leak the thread state, if the
+            // interpreter has shut down when we're getting
+            // deallocated, we can't run the cleanup code that
+            // deleting it would imply.
+            return;
+        }
+
+        AddToCleanupQueue(state);
+
+    }
+
+private:
+
+    // If the state has an allocated main greenlet:
+    // - mark the greenlet as dead by disassociating it from the state;
+    // - return 1
+    // Otherwise, return 0.
+    static bool
+    MarkGreenletDeadIfNeeded(ThreadState* const state)
+    {
+        if (state && state->has_main_greenlet()) {
+            // mark the thread as dead ASAP.
+            // this is racy! If we try to throw or switch to a
+            // greenlet from this thread from some other thread before
+            // we clear the state pointer, it won't realize the state
+            // is dead which can crash the process.
+            PyGreenlet* p(state->borrow_main_greenlet().borrow());
+            assert(p->pimpl->thread_state() == state || p->pimpl->thread_state() == nullptr);
+            dynamic_cast<MainGreenlet*>(p->pimpl)->thread_state(nullptr);
+           return true;
+        }
+        return false;
+    }
+
+    static void
+    AddToCleanupQueue(ThreadState* const state)
+    {
+        assert(state && state->has_main_greenlet());
+
+        // NOTE: Because we're not holding the GIL here, some other
+        // Python thread could run and call ``os.fork()``, which would
+        // be bad if that happened while we are holding the cleanup
+        // lock (it wouldn't function in the child process).
+        // Make a best effort to try to keep the duration we hold the
+        // lock short.
+        // TODO: On platforms that support it, use ``pthread_atfork`` to
+        // drop this lock.
+        LockGuard cleanup_lock(*mod_globs->thread_states_to_destroy_lock);
+
+        mod_globs->queue_to_destroy(state);
+        if (mod_globs->thread_states_to_destroy.size() == 1) {
+            // We added the first item to the queue. We need to schedule
+            // the cleanup.
+
+            // A size greater than 1 means that we have already added the pending call,
+            // and in fact, it may be executing now.
+            // If it is executing, our lock makes sure that it will see the item we just added
+            // to the queue on its next iteration (after we release the lock)
+            //
+            // A size of 1 means there is no pending call, OR the pending call is
+            // currently executing, has dropped the lock, and is deleting the last item
+            // from the queue; its next iteration will go ahead and delete the item we just added.
+            // And the pending call we schedule here will have no work to do.
+            int result = AddPendingCall(
+                           PendingCallback_DestroyQueueWithGIL,
+                            nullptr);
+            if (result < 0) {
+                // Hmm, what can we do here?
+                fprintf(stderr,
+                        "greenlet: WARNING: failed in call to Py_AddPendingCall; "
+                        "expect a memory leak.\n");
+            }
+        }
+    }
+
+    static int
+    PendingCallback_DestroyQueueWithGIL(void* UNUSED(arg))
+    {
+        // We're holding the GIL here, so no Python code should be able to
+        // run to call ``os.fork()``.
+        while (1) {
+            ThreadState* to_destroy;
+            {
+                LockGuard cleanup_lock(*mod_globs->thread_states_to_destroy_lock);
+                if (mod_globs->thread_states_to_destroy.empty()) {
+                    break;
+                }
+                to_destroy = mod_globs->take_next_to_destroy();
+            }
+            assert(to_destroy);
+            assert(to_destroy->has_main_greenlet());
+            // Drop the lock while we do the actual deletion.
+            // This allows other calls to MarkGreenletDeadAndQueueCleanup
+            // to enter and add to our queue.
+            DestroyOneWithGIL(to_destroy);
+        }
+        return 0;
+    }
+
+    static void
+    DestroyOneWithGIL(const ThreadState* const state)
+    {
+        // Holding the GIL.
+        // Passed a non-shared pointer to the actual thread state.
+        // state -> main greenlet
+        assert(state->has_main_greenlet());
+        PyGreenlet* main(state->borrow_main_greenlet());
+        // When we need to do cross-thread operations, we check this.
+        // A NULL value means the thread died some time ago.
+        // We do this here, rather than in a Python dealloc function
+        // for the greenlet, in case there's still a reference out
+        // there.
+        dynamic_cast<MainGreenlet*>(main->pimpl)->thread_state(nullptr);
+
+        delete state; // Deleting this runs the destructor, DECREFs the main greenlet.
+    }
+
+    // ensure this is actually defined.
+    static_assert(GREENLET_BROKEN_PY_ADD_PENDING == 1 || GREENLET_BROKEN_PY_ADD_PENDING == 0,
+                  "GREENLET_BROKEN_PY_ADD_PENDING not defined correctly.");
+
+#if GREENLET_BROKEN_PY_ADD_PENDING
+    static int _push_pending_call(struct _pending_calls *pending,
+                                  int (*func)(void *), void *arg)
+    {
+        int i = pending->last;
+        int j = (i + 1) % NPENDINGCALLS;
+        if (j == pending->first) {
+            return -1; /* Queue full */
+        }
+        pending->calls[i].func = func;
+        pending->calls[i].arg = arg;
+        pending->last = j;
+        return 0;
+    }
+
+    static int AddPendingCall(int (*func)(void *), void *arg)
+    {
+        _PyRuntimeState *runtime = &_PyRuntime;
+        if (!runtime) {
+            // obviously impossible
+            return 0;
+        }
+        struct _pending_calls *pending = &runtime->ceval.pending;
+        if (!pending->lock) {
+            return 0;
+        }
+        int result = 0;
+        PyThread_acquire_lock(pending->lock, WAIT_LOCK);
+        if (!pending->finishing) {
+            result = _push_pending_call(pending, func, arg);
+        }
+        PyThread_release_lock(pending->lock);
+        SIGNAL_PENDING_CALLS(&runtime->ceval);
+        return result;
+    }
+#else
+    // Python < 3.8 or >= 3.9
+    static int AddPendingCall(int (*func)(void*), void* arg)
+    {
+        // If the interpreter is in the middle of finalizing, we can't add a
+        // pending call. Trying to do so will end up in a SIGSEGV, as
+        // Py_AddPendingCall will not be able to get the interpreter and will
+        // try to dereference a NULL pointer. It's possible this can still
+        // segfault if we happen to get context switched, and maybe we should
+        // just always implement our own AddPendingCall, but I'd like to see if
+        // this works first
+#if GREENLET_PY313
+        if (Py_IsFinalizing()) {
+#else
+        if (_Py_IsFinalizing()) {
+#endif
+#ifdef GREENLET_DEBUG
+            // No need to log in the general case. Yes, we'll leak,
+            // but we're shutting down so it should be ok.
+            fprintf(stderr,
+                    "greenlet: WARNING: Interpreter is finalizing. Ignoring "
+                    "call to Py_AddPendingCall; \n");
+#endif
+            return 0;
+        }
+        return Py_AddPendingCall(func, arg);
+    }
+#endif
+
+
+
+
+};
+};
+
+}; // namespace greenlet
+
+// The intent when GET_THREAD_STATE() is needed multiple times in a
+// function is to take a reference to its return value in a local
+// variable, to avoid the thread-local indirection. On some platforms
+// (macOS), accessing a thread-local involves a function call (plus an
+// initial function call in each function that uses a thread local);
+// in contrast, static volatile variables are at some pre-computed
+// offset.
+typedef greenlet::ThreadStateCreator<greenlet::ThreadState_DestroyNoGIL::MarkGreenletDeadAndQueueCleanup> ThreadStateCreator;
+static thread_local ThreadStateCreator g_thread_state_global;
+#define GET_THREAD_STATE() g_thread_state_global
+
+#endif //T_THREADSTATE_DESTROY