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tdutils/td/utils/port/RwMutex.h

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+/*
+    This file is part of TON Blockchain Library.
+
+    TON Blockchain Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    TON Blockchain Library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.
+
+    Copyright 2017-2019 Telegram Systems LLP
+*/
+#pragma once
+
+#include "td/utils/port/config.h"
+
+#include "td/utils/common.h"
+#include "td/utils/Status.h"
+
+#if TD_PORT_POSIX
+#include <pthread.h>
+#endif
+
+#include <memory>
+
+namespace td {
+
+class RwMutex {
+ public:
+  RwMutex() {
+    init();
+  }
+  RwMutex(const RwMutex &) = delete;
+  RwMutex &operator=(const RwMutex &) = delete;
+  RwMutex(RwMutex &&other) {
+    init();
+    other.clear();
+  }
+  RwMutex &operator=(RwMutex &&other) {
+    other.clear();
+    return *this;
+  }
+  ~RwMutex() {
+    clear();
+  }
+
+  bool empty() const {
+    return !is_valid_;
+  }
+
+  void init();
+
+  void clear();
+
+  struct ReadUnlock {
+    void operator()(RwMutex *ptr) {
+      ptr->unlock_read_unsafe();
+    }
+  };
+  struct WriteUnlock {
+    void operator()(RwMutex *ptr) {
+      ptr->unlock_write_unsafe();
+    }
+  };
+
+  using ReadLock = std::unique_ptr<RwMutex, ReadUnlock>;
+  using WriteLock = std::unique_ptr<RwMutex, WriteUnlock>;
+
+  Result<ReadLock> lock_read() TD_WARN_UNUSED_RESULT {
+    lock_read_unsafe();
+    return ReadLock(this);
+  }
+
+  Result<WriteLock> lock_write() TD_WARN_UNUSED_RESULT {
+    lock_write_unsafe();
+    return WriteLock(this);
+  }
+
+  void lock_read_unsafe();
+
+  void lock_write_unsafe();
+
+  void unlock_read_unsafe();
+
+  void unlock_write_unsafe();
+
+ private:
+  bool is_valid_ = false;
+#if TD_PORT_POSIX
+  pthread_rwlock_t mutex_;
+#elif TD_PORT_WINDOWS
+  unique_ptr<SRWLOCK> mutex_;
+#endif
+};
+
+inline void RwMutex::init() {
+  CHECK(empty());
+  is_valid_ = true;
+#if TD_PORT_POSIX
+  pthread_rwlock_init(&mutex_, nullptr);
+#elif TD_PORT_WINDOWS
+  mutex_ = make_unique<SRWLOCK>();
+  InitializeSRWLock(mutex_.get());
+#endif
+}
+
+inline void RwMutex::clear() {
+  if (is_valid_) {
+#if TD_PORT_POSIX
+    pthread_rwlock_destroy(&mutex_);
+#elif TD_PORT_WINDOWS
+    mutex_.release();
+#endif
+    is_valid_ = false;
+  }
+}
+
+inline void RwMutex::lock_read_unsafe() {
+  CHECK(!empty());
+// TODO error handling
+#if TD_PORT_POSIX
+  pthread_rwlock_rdlock(&mutex_);
+#elif TD_PORT_WINDOWS
+  AcquireSRWLockShared(mutex_.get());
+#endif
+}
+
+inline void RwMutex::lock_write_unsafe() {
+  CHECK(!empty());
+#if TD_PORT_POSIX
+  pthread_rwlock_wrlock(&mutex_);
+#elif TD_PORT_WINDOWS
+  AcquireSRWLockExclusive(mutex_.get());
+#endif
+}
+
+inline void RwMutex::unlock_read_unsafe() {
+  CHECK(!empty());
+#if TD_PORT_POSIX
+  pthread_rwlock_unlock(&mutex_);
+#elif TD_PORT_WINDOWS
+  ReleaseSRWLockShared(mutex_.get());
+#endif
+}
+
+inline void RwMutex::unlock_write_unsafe() {
+  CHECK(!empty());
+#if TD_PORT_POSIX
+  pthread_rwlock_unlock(&mutex_);
+#elif TD_PORT_WINDOWS
+  ReleaseSRWLockExclusive(mutex_.get());
+#endif
+}
+
+}  // namespace td