Replace RE2 import with a dependency

third_party/re2/util/mutex.h

-// Copyright 2007 The RE2 Authors.  All Rights Reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-/*
- * A simple mutex wrapper, supporting locks and read-write locks.
- * You should assume the locks are *not* re-entrant.
- */
-
-#ifndef RE2_UTIL_MUTEX_H_
-#define RE2_UTIL_MUTEX_H_
-
-#include <stdlib.h>
-
-#if !defined(_WIN32)
-#include <unistd.h>  // For POSIX options
-#endif
-
-namespace re2 {
-
-#if !defined(_WIN32)
-  // Possible values of POSIX options:
-  //   -1 means not supported,
-  //    0 means maybe supported (query at runtime),
-  //   >0 means supported.
-# if defined(_POSIX_THREADS) && _POSIX_THREADS > 0
-#   define HAVE_PTHREAD 1
-# else
-#   define HAVE_PTHREAD 0
-# endif
-# if defined(_POSIX_READER_WRITER_LOCKS) && _POSIX_READER_WRITER_LOCKS > 0
-#   define HAVE_RWLOCK 1
-# else
-#   define HAVE_RWLOCK 0
-# endif
-#else
-# define HAVE_PTHREAD 0
-# define HAVE_RWLOCK 0
-#endif
-
-#if defined(NO_THREADS)
-  typedef int MutexType;      // to keep a lock-count
-#elif HAVE_PTHREAD && HAVE_RWLOCK
-  // Needed for pthread_rwlock_*.  If it causes problems, you could take it
-  // out, but then you'd have to set HAVE_RWLOCK to 0 (at least on linux --
-  // it *does* cause problems for FreeBSD, or MacOSX, but isn't needed
-  // for locking there.)
-# ifdef __linux__
-#   undef _XOPEN_SOURCE
-#   define _XOPEN_SOURCE 500  // may be needed to get the rwlock calls
-# endif
-# include <pthread.h>
-  typedef pthread_rwlock_t MutexType;
-#elif HAVE_PTHREAD
-# include <pthread.h>
-  typedef pthread_mutex_t MutexType;
-#elif defined(_WIN32)
-# ifndef WIN32_LEAN_AND_MEAN
-#   define WIN32_LEAN_AND_MEAN  // We only need minimal includes
-# endif
-# ifdef GMUTEX_TRYLOCK
-  // We need Windows NT or later for TryEnterCriticalSection().  If you
-  // don't need that functionality, you can remove these _WIN32_WINNT
-  // lines, and change TryLock() to assert(0) or something.
-#   ifndef _WIN32_WINNT
-#     define _WIN32_WINNT 0x0400
-#   endif
-# endif
-# include <windows.h>
-  typedef CRITICAL_SECTION MutexType;
-#else
-# error Need to implement mutex.h for your architecture, or #define NO_THREADS
-#endif
-
-class Mutex {
- public:
-  // Create a Mutex that is not held by anybody.
-  inline Mutex();
-
-  // Destructor
-  inline ~Mutex();
-
-  inline void Lock();    // Block if needed until free then acquire exclusively
-  inline void Unlock();  // Release a lock acquired via Lock()
-  inline bool TryLock(); // If free, Lock() and return true, else return false
-  // Note that on systems that don't support read-write locks, these may
-  // be implemented as synonyms to Lock() and Unlock().  So you can use
-  // these for efficiency, but don't use them anyplace where being able
-  // to do shared reads is necessary to avoid deadlock.
-  inline void ReaderLock();   // Block until free or shared then acquire a share
-  inline void ReaderUnlock(); // Release a read share of this Mutex
-  inline void WriterLock() { Lock(); }     // Acquire an exclusive lock
-  inline void WriterUnlock() { Unlock(); } // Release a lock from WriterLock()
-  inline void AssertHeld() { }
-
- private:
-  MutexType mutex_;
-
-  // Catch the error of writing Mutex when intending MutexLock.
-  Mutex(Mutex *ignored);
-  // Disallow "evil" constructors
-  Mutex(const Mutex&);
-  void operator=(const Mutex&);
-};
-
-// Now the implementation of Mutex for various systems
-#if defined(NO_THREADS)
-
-// When we don't have threads, we can be either reading or writing,
-// but not both.  We can have lots of readers at once (in no-threads
-// mode, that's most likely to happen in recursive function calls),
-// but only one writer.  We represent this by having mutex_ be -1 when
-// writing and a number > 0 when reading (and 0 when no lock is held).
-//
-// In debug mode, we assert these invariants, while in non-debug mode
-// we do nothing, for efficiency.  That's why everything is in an
-// assert.
-#include <assert.h>
-
-Mutex::Mutex() : mutex_(0) { }
-Mutex::~Mutex()            { assert(mutex_ == 0); }
-void Mutex::Lock()         { assert(--mutex_ == -1); }
-void Mutex::Unlock()       { assert(mutex_++ == -1); }
-bool Mutex::TryLock()      { if (mutex_) return false; Lock(); return true; }
-void Mutex::ReaderLock()   { assert(++mutex_ > 0); }
-void Mutex::ReaderUnlock() { assert(mutex_-- > 0); }
-
-#elif HAVE_PTHREAD && HAVE_RWLOCK
-
-#define SAFE_PTHREAD(fncall)  do { if ((fncall) != 0) abort(); } while (0)
-
-Mutex::Mutex()             { SAFE_PTHREAD(pthread_rwlock_init(&mutex_, NULL)); }
-Mutex::~Mutex()            { SAFE_PTHREAD(pthread_rwlock_destroy(&mutex_)); }
-void Mutex::Lock()         { SAFE_PTHREAD(pthread_rwlock_wrlock(&mutex_)); }
-void Mutex::Unlock()       { SAFE_PTHREAD(pthread_rwlock_unlock(&mutex_)); }
-bool Mutex::TryLock()      { return pthread_rwlock_trywrlock(&mutex_) == 0; }
-void Mutex::ReaderLock()   { SAFE_PTHREAD(pthread_rwlock_rdlock(&mutex_)); }
-void Mutex::ReaderUnlock() { SAFE_PTHREAD(pthread_rwlock_unlock(&mutex_)); }
-
-#undef SAFE_PTHREAD
-
-#elif HAVE_PTHREAD
-
-#define SAFE_PTHREAD(fncall)  do { if ((fncall) != 0) abort(); } while (0)
-
-Mutex::Mutex()             { SAFE_PTHREAD(pthread_mutex_init(&mutex_, NULL)); }
-Mutex::~Mutex()            { SAFE_PTHREAD(pthread_mutex_destroy(&mutex_)); }
-void Mutex::Lock()         { SAFE_PTHREAD(pthread_mutex_lock(&mutex_)); }
-void Mutex::Unlock()       { SAFE_PTHREAD(pthread_mutex_unlock(&mutex_)); }
-bool Mutex::TryLock()      { return pthread_mutex_trylock(&mutex_) == 0; }
-void Mutex::ReaderLock()   { Lock(); }      // we don't have read-write locks
-void Mutex::ReaderUnlock() { Unlock(); }
-#undef SAFE_PTHREAD
-
-#elif defined(_WIN32)
-
-Mutex::Mutex()             { InitializeCriticalSection(&mutex_); }
-Mutex::~Mutex()            { DeleteCriticalSection(&mutex_); }
-void Mutex::Lock()         { EnterCriticalSection(&mutex_); }
-void Mutex::Unlock()       { LeaveCriticalSection(&mutex_); }
-bool Mutex::TryLock()      { return TryEnterCriticalSection(&mutex_) != 0; }
-void Mutex::ReaderLock()   { Lock(); }      // we don't have read-write locks
-void Mutex::ReaderUnlock() { Unlock(); }
-
-#endif
-
-
-// --------------------------------------------------------------------------
-// Some helper classes
-
-// MutexLock(mu) acquires mu when constructed and releases it when destroyed.
-class MutexLock {
- public:
-  explicit MutexLock(Mutex *mu) : mu_(mu) { mu_->Lock(); }
-  ~MutexLock() { mu_->Unlock(); }
- private:
-  Mutex * const mu_;
-  // Disallow "evil" constructors
-  MutexLock(const MutexLock&);
-  void operator=(const MutexLock&);
-};
-
-// ReaderMutexLock and WriterMutexLock do the same, for rwlocks
-class ReaderMutexLock {
- public:
-  explicit ReaderMutexLock(Mutex *mu) : mu_(mu) { mu_->ReaderLock(); }
-  ~ReaderMutexLock() { mu_->ReaderUnlock(); }
- private:
-  Mutex * const mu_;
-  // Disallow "evil" constructors
-  ReaderMutexLock(const ReaderMutexLock&);
-  void operator=(const ReaderMutexLock&);
-};
-
-class WriterMutexLock {
- public:
-  explicit WriterMutexLock(Mutex *mu) : mu_(mu) { mu_->WriterLock(); }
-  ~WriterMutexLock() { mu_->WriterUnlock(); }
- private:
-  Mutex * const mu_;
-  // Disallow "evil" constructors
-  WriterMutexLock(const WriterMutexLock&);
-  void operator=(const WriterMutexLock&);
-};
-
-// Catch bug where variable name is omitted, e.g. MutexLock (&mu);
-#define MutexLock(x) COMPILE_ASSERT(0, mutex_lock_decl_missing_var_name)
-#define ReaderMutexLock(x) COMPILE_ASSERT(0, rmutex_lock_decl_missing_var_name)
-#define WriterMutexLock(x) COMPILE_ASSERT(0, wmutex_lock_decl_missing_var_name)
-
-// Provide safe way to declare and use global, linker-initialized mutex. Sigh.
-#if HAVE_PTHREAD
-
-#define GLOBAL_MUTEX(name) \
-        static pthread_mutex_t (name) = PTHREAD_MUTEX_INITIALIZER
-#define GLOBAL_MUTEX_LOCK(name) \
-        pthread_mutex_lock(&(name))
-#define GLOBAL_MUTEX_UNLOCK(name) \
-        pthread_mutex_unlock(&(name))
-
-#else
-
-#define GLOBAL_MUTEX(name) \
-        static Mutex name
-#define GLOBAL_MUTEX_LOCK(name) \
-        name.Lock()
-#define GLOBAL_MUTEX_UNLOCK(name) \
-        name.Unlock()
-
-#endif
-
-}  // namespace re2
-
-#endif  /* #define RE2_UTIL_MUTEX_H_ */