Release Cosmopolitan v3.6.0

This release is an atomic upgrade to GCC 14.1.0 with C23 and C++23

third_party/libcxx/shared_mutex.cpp

@@ -0,0 +1,93 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <mutex>
+#include <shared_mutex>
+#if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
+#  pragma comment(lib, "pthread")
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// Shared Mutex Base
+__shared_mutex_base::__shared_mutex_base() : __state_(0) {}
+
+// Exclusive ownership
+
+void __shared_mutex_base::lock() {
+  unique_lock<mutex> lk(__mut_);
+  while (__state_ & __write_entered_)
+    __gate1_.wait(lk);
+  __state_ |= __write_entered_;
+  while (__state_ & __n_readers_)
+    __gate2_.wait(lk);
+}
+
+bool __shared_mutex_base::try_lock() {
+  unique_lock<mutex> lk(__mut_);
+  if (__state_ == 0) {
+    __state_ = __write_entered_;
+    return true;
+  }
+  return false;
+}
+
+void __shared_mutex_base::unlock() {
+  lock_guard<mutex> _(__mut_);
+  __state_ = 0;
+  __gate1_.notify_all();
+}
+
+// Shared ownership
+
+void __shared_mutex_base::lock_shared() {
+  unique_lock<mutex> lk(__mut_);
+  while ((__state_ & __write_entered_) || (__state_ & __n_readers_) == __n_readers_)
+    __gate1_.wait(lk);
+  unsigned num_readers = (__state_ & __n_readers_) + 1;
+  __state_ &= ~__n_readers_;
+  __state_ |= num_readers;
+}
+
+bool __shared_mutex_base::try_lock_shared() {
+  unique_lock<mutex> lk(__mut_);
+  unsigned num_readers = __state_ & __n_readers_;
+  if (!(__state_ & __write_entered_) && num_readers != __n_readers_) {
+    ++num_readers;
+    __state_ &= ~__n_readers_;
+    __state_ |= num_readers;
+    return true;
+  }
+  return false;
+}
+
+void __shared_mutex_base::unlock_shared() {
+  lock_guard<mutex> _(__mut_);
+  unsigned num_readers = (__state_ & __n_readers_) - 1;
+  __state_ &= ~__n_readers_;
+  __state_ |= num_readers;
+  if (__state_ & __write_entered_) {
+    if (num_readers == 0)
+      __gate2_.notify_one();
+  } else {
+    if (num_readers == __n_readers_ - 1)
+      __gate1_.notify_one();
+  }
+}
+
+// Shared Timed Mutex
+// These routines are here for ABI stability
+shared_timed_mutex::shared_timed_mutex() : __base_() {}
+void shared_timed_mutex::lock() { return __base_.lock(); }
+bool shared_timed_mutex::try_lock() { return __base_.try_lock(); }
+void shared_timed_mutex::unlock() { return __base_.unlock(); }
+void shared_timed_mutex::lock_shared() { return __base_.lock_shared(); }
+bool shared_timed_mutex::try_lock_shared() { return __base_.try_lock_shared(); }
+void shared_timed_mutex::unlock_shared() { return __base_.unlock_shared(); }
+
+_LIBCPP_END_NAMESPACE_STD