From bda3a779bdd567e5b889ceebffa86cdd8faec725 Mon Sep 17 00:00:00 2001
From: Guogang Li <guogang@google.com>
Date: Tue, 4 Apr 2023 11:39:38 -0700
Subject: [PATCH] Fixed the crash in Timer::Stop

PiperOrigin-RevId: 521822379
---
 .../platform/implementation/windows/BUILD     |  2 ++
 .../platform/implementation/windows/timer.cc  |  9 +++++++-
 .../platform/implementation/windows/timer.h   | 22 ++++++++++++-------
 3 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/internal/platform/implementation/windows/BUILD b/internal/platform/implementation/windows/BUILD
index a4da868d..2c134c70 100644
--- a/internal/platform/implementation/windows/BUILD
+++ b/internal/platform/implementation/windows/BUILD
@@ -50,6 +50,8 @@ cc_library(
         "//internal/platform:logging",
         "//internal/platform/implementation:types",
         "//internal/platform/implementation/windows/generated:types",
+        "@com_google_absl//absl/base:core_headers",
+        "@com_google_absl//absl/synchronization",
     ],
 )
 
diff --git a/internal/platform/implementation/windows/timer.cc b/internal/platform/implementation/windows/timer.cc
index c960bf04..b6fbed51 100644
--- a/internal/platform/implementation/windows/timer.cc
+++ b/internal/platform/implementation/windows/timer.cc
@@ -16,6 +16,7 @@
 
 #include <memory>
 
+#include "absl/synchronization/mutex.h"
 #include "internal/platform/logging.h"
 
 namespace nearby {
@@ -25,6 +26,8 @@ Timer::~Timer() { Stop(); }
 
 bool Timer::Create(int delay, int interval,
                    absl::AnyInvocable<void()> callback) {
+  absl::MutexLock lock(&mutex_);
+
   if ((delay < 0) || (interval < 0)) {
     NEARBY_LOGS(WARNING) << "Delay and interval shouldn\'t be negative value.";
     return false;
@@ -58,6 +61,8 @@ bool Timer::Create(int delay, int interval,
 }
 
 bool Timer::Stop() {
+  absl::MutexLock lock(&mutex_);
+
   if (timer_queue_handle_ == nullptr) {
     return true;
   }
@@ -81,6 +86,8 @@ bool Timer::Stop() {
 }
 
 bool Timer::FireNow() {
+  absl::MutexLock lock(&mutex_);
+
   if (!timer_queue_handle_ || !callback_) {
     return false;
   }
@@ -92,7 +99,7 @@ bool Timer::FireNow() {
 void CALLBACK Timer::TimerRoutine(PVOID lpParam, BOOLEAN TimerOrWaitFired) {
   absl::AnyInvocable<void()>* callback =
       reinterpret_cast<absl::AnyInvocable<void()>*>(lpParam);
-  if (*callback != NULL) {
+  if (*callback != nullptr) {
     (*callback)();
   }
 }
diff --git a/internal/platform/implementation/windows/timer.h b/internal/platform/implementation/windows/timer.h
index 2c9edd49..9c56c253 100644
--- a/internal/platform/implementation/windows/timer.h
+++ b/internal/platform/implementation/windows/timer.h
@@ -17,6 +17,10 @@
 
 #include <windows.h>
 
+#include <memory>
+
+#include "absl/base/thread_annotations.h"
+#include "absl/synchronization/mutex.h"
 #include "internal/platform/implementation/timer.h"
 
 namespace nearby {
@@ -28,18 +32,20 @@ class Timer : public api::Timer {
   ~Timer() override;
 
   bool Create(int delay, int interval,
-              absl::AnyInvocable<void()> callback) override;
-  bool Stop() override;
-  bool FireNow() override;
+              absl::AnyInvocable<void()> callback) override
+      ABSL_LOCKS_EXCLUDED(mutex_);
+  bool Stop() override ABSL_LOCKS_EXCLUDED(mutex_);
+  bool FireNow() override ABSL_LOCKS_EXCLUDED(mutex_);
 
  private:
   static void CALLBACK TimerRoutine(PVOID lpParam, BOOLEAN TimerOrWaitFired);
 
-  int delay_;
-  int interval_;
-  absl::AnyInvocable<void()> callback_;
-  HANDLE handle_ = NULL;
-  HANDLE timer_queue_handle_ = NULL;
+  mutable absl::Mutex mutex_;
+  int delay_ ABSL_GUARDED_BY(mutex_);
+  int interval_ ABSL_GUARDED_BY(mutex_);
+  absl::AnyInvocable<void()> callback_ ABSL_GUARDED_BY(mutex_);
+  HANDLE handle_ ABSL_GUARDED_BY(mutex_) = nullptr;
+  HANDLE timer_queue_handle_ ABSL_GUARDED_BY(mutex_) = nullptr;
 };
 
 }  // namespace windows