chore: import upstream snapshot with attribution

2026-07-13 13:29:29 +08:00
commit f52cf32e56
1718 changed files with 366293 additions and 0 deletions
@@ -0,0 +1,75 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "butil/at_exit.h"
+
+#include <stddef.h>
+#include <ostream>
+
+#include "butil/logging.h"
+
+namespace butil {
+
+// Keep a stack of registered AtExitManagers.  We always operate on the most
+// recent, and we should never have more than one outside of testing (for a
+// statically linked version of this library).  Testing may use the shadow
+// version of the constructor, and if we are building a dynamic library we may
+// end up with multiple AtExitManagers on the same process.  We don't protect
+// this for thread-safe access, since it will only be modified in testing.
+static AtExitManager* g_top_manager = NULL;
+
+AtExitManager::AtExitManager() : next_manager_(g_top_manager) {
+// If multiple modules instantiate AtExitManagers they'll end up living in this
+// module... they have to coexist.
+#if !defined(COMPONENT_BUILD)
+  DCHECK(!g_top_manager);
+#endif
+  g_top_manager = this;
+}
+
+AtExitManager::~AtExitManager() {
+  if (!g_top_manager) {
+    NOTREACHED() << "Tried to ~AtExitManager without an AtExitManager";
+    return;
+  }
+  DCHECK_EQ(this, g_top_manager);
+
+  ProcessCallbacksNow();
+  g_top_manager = next_manager_;
+}
+
+// static
+void AtExitManager::RegisterCallback(AtExitCallbackType func, void* param) {
+  DCHECK(func);
+  if (!g_top_manager) {
+    NOTREACHED() << "Tried to RegisterCallback without an AtExitManager";
+    return;
+  }
+
+  AutoLock lock(g_top_manager->lock_);
+  g_top_manager->stack_.push({func, param});
+}
+
+// static
+void AtExitManager::ProcessCallbacksNow() {
+  if (!g_top_manager) {
+    NOTREACHED() << "Tried to ProcessCallbacksNow without an AtExitManager";
+    return;
+  }
+
+  AutoLock lock(g_top_manager->lock_);
+
+  while (!g_top_manager->stack_.empty()) {
+    Callback task = g_top_manager->stack_.top();
+    task.func(task.param);
+    g_top_manager->stack_.pop();
+  }
+}
+
+AtExitManager::AtExitManager(bool shadow) : next_manager_(g_top_manager) {
+  DCHECK(shadow || !g_top_manager);
+  g_top_manager = this;
+}
+
+}  // namespace butil