[Lldb-commits] [lldb] [lldb] Implement coalescing of disjoint progress events (PR #84854)

[Chelsea Cassanova via lldb-commits]

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@@ -0,0 +1,88 @@
+//===-- Alarm.h -------------------------------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_HOST_ALARM_H
+#define LLDB_HOST_ALARM_H
+
+#include "lldb/Host/HostThread.h"
+#include "lldb/lldb-types.h"
+#include "llvm/Support/Chrono.h"
+
+namespace lldb_private {
+
+class Alarm {
+public:
+  using Handle = uint64_t;
+  using Callback = std::function<void()>;
+  using TimePoint = llvm::sys::TimePoint<>;
+  using Duration = std::chrono::milliseconds;
+
+  Alarm(Duration timeout, bool run_callback_on_exit = false);
+  ~Alarm();
+
+  Handle Create(Callback callback);
+  bool Restart(Handle handle);
+  bool Cancel(Handle handle);
+
+  static constexpr Handle INVALID_HANDLE = 0;
+
+private:
+  /// Helper functions to start, stop and check the status of the alarm thread.
+  /// @{
+  void StartAlarmThread();
+  void StopAlarmThread();
+  bool AlarmThreadRunning();
+  /// @}
+
+  /// Return an unique, monotonically increasing handle.
+  static Handle GetNextUniqueHandle();
+
+  TimePoint GetNextExpiration() const;
+
+  /// Alarm entry.
+  struct Entry {
+    Handle handle;
+    Callback callback;
+    TimePoint expiration;
+
+    Entry(Callback callback, TimePoint expiration);
+    bool operator==(const Entry &rhs) { return handle == rhs.handle; }
+  };
+
+  /// List of alarm entries.
+  std::vector<Entry> m_entries;
+
+  /// Timeout between when an alarm is created and when it fires.
+  Duration m_timeout;
+
+  /// The alarm thread.
+  /// @{
+  HostThread m_alarm_thread;
+  lldb::thread_result_t AlarmThread();
+  /// @}
+
+  /// Synchronize access between the alarm thread and the main thread.
+  std::mutex m_alarm_mutex;
+
+  /// Condition variable used to wake up the alarm thread.
+  std::condition_variable m_alarm_cv;
+
+  /// Flag to signal the alarm thread that something changed and we need to
+  // recompute the next alarm.
----------------
chelcassanova wrote:

nit: missing third slash for doxygen?

https://github.com/llvm/llvm-project/pull/84854