mozglue/misc/Mutex_posix.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "mozilla/Assertions.h"
   8
   9 #include <errno.h>
  10 #include <pthread.h>
  11 #include <stdio.h>
  12
  13 #if defined(XP_DARWIN)
  14 #  include <pthread_spis.h>
  15 #endif
  16
  17 #include "mozilla/PlatformMutex.h"
  18 #include "MutexPlatformData_posix.h"
  19
  20 #define REPORT_PTHREADS_ERROR(result, msg) \
  21   {                                        \
  22     errno = result;                        \
  23     perror(msg);                           \
  24     MOZ_CRASH(msg);                        \
  25   }
  26
  27 #define TRY_CALL_PTHREADS(call, msg)      \
  28   {                                       \
  29     int result = (call);                  \
  30     if (result != 0) {                    \
  31       REPORT_PTHREADS_ERROR(result, msg); \
  32     }                                     \
  33   }
  34
  35 mozilla::detail::MutexImpl::MutexImpl() {
  36   pthread_mutexattr_t* attrp = nullptr;
  37
  38 #if defined(DEBUG)
  39 #  define MUTEX_KIND PTHREAD_MUTEX_ERRORCHECK
  40 // Linux with glibc, FreeBSD and macOS 10.14+ support adaptive mutexes that
  41 // spin for a short number of tries before sleeping.  NSPR's locks did this,
  42 // too, and it seems like a reasonable thing to do.
  43 #elif (defined(__linux__) && defined(__GLIBC__)) || defined(__FreeBSD__)
  44 #  define MUTEX_KIND PTHREAD_MUTEX_ADAPTIVE_NP
  45 #elif defined(XP_DARWIN)
  46 #  if defined(PTHREAD_MUTEX_POLICY_FIRSTFIT_NP)
  47 #    define POLICY_KIND PTHREAD_MUTEX_POLICY_FIRSTFIT_NP
  48 #  else
  49 #    define POLICY_KIND (3)  // The definition is missing in old SDKs
  50 #  endif
  51 #endif
  52
  53 #if defined(MUTEX_KIND) || defined(POLICY_KIND)
  54 #  define ATTR_REQUIRED
  55 #endif
  56
  57 #if defined(ATTR_REQUIRED)
  58   pthread_mutexattr_t attr;
  59
  60   TRY_CALL_PTHREADS(
  61       pthread_mutexattr_init(&attr),
  62       "mozilla::detail::MutexImpl::MutexImpl: pthread_mutexattr_init failed");
  63
  64 #  if defined(MUTEX_KIND)
  65   TRY_CALL_PTHREADS(pthread_mutexattr_settype(&attr, MUTEX_KIND),
  66                     "mozilla::detail::MutexImpl::MutexImpl: "
  67                     "pthread_mutexattr_settype failed");
  68 #  elif defined(POLICY_KIND)
  69   if (__builtin_available(macOS 10.14, *)) {
  70     TRY_CALL_PTHREADS(pthread_mutexattr_setpolicy_np(&attr, POLICY_KIND),
  71                       "mozilla::detail::MutexImpl::MutexImpl: "
  72                       "pthread_mutexattr_setpolicy_np failed");
  73   }
  74 #  endif
  75   attrp = &attr;
  76 #endif
  77
  78   TRY_CALL_PTHREADS(
  79       pthread_mutex_init(&platformData()->ptMutex, attrp),
  80       "mozilla::detail::MutexImpl::MutexImpl: pthread_mutex_init failed");
  81
  82 #if defined(ATTR_REQUIRED)
  83   TRY_CALL_PTHREADS(pthread_mutexattr_destroy(&attr),
  84                     "mozilla::detail::MutexImpl::MutexImpl: "
  85                     "pthread_mutexattr_destroy failed");
  86 #endif
  87 }
  88
  89 mozilla::detail::MutexImpl::~MutexImpl() {
  90   TRY_CALL_PTHREADS(
  91       pthread_mutex_destroy(&platformData()->ptMutex),
  92       "mozilla::detail::MutexImpl::~MutexImpl: pthread_mutex_destroy failed");
  93 }
  94
  95 inline void mozilla::detail::MutexImpl::mutexLock() {
  96   TRY_CALL_PTHREADS(
  97       pthread_mutex_lock(&platformData()->ptMutex),
  98       "mozilla::detail::MutexImpl::mutexLock: pthread_mutex_lock failed");
  99 }
 100
 101 bool mozilla::detail::MutexImpl::tryLock() { return mutexTryLock(); }
 102
 103 bool mozilla::detail::MutexImpl::mutexTryLock() {
 104   int result = pthread_mutex_trylock(&platformData()->ptMutex);
 105   if (result == 0) {
 106     return true;
 107   }
 108
 109   if (result == EBUSY) {
 110     return false;
 111   }
 112
 113   REPORT_PTHREADS_ERROR(
 114       result,
 115       "mozilla::detail::MutexImpl::mutexTryLock: pthread_mutex_trylock failed");
 116 }
 117
 118 void mozilla::detail::MutexImpl::lock() { mutexLock(); }
 119
 120 void mozilla::detail::MutexImpl::unlock() {
 121   TRY_CALL_PTHREADS(
 122       pthread_mutex_unlock(&platformData()->ptMutex),
 123       "mozilla::detail::MutexImpl::unlock: pthread_mutex_unlock failed");
 124 }
 125
 126 #undef TRY_CALL_PTHREADS
 127
 128 mozilla::detail::MutexImpl::PlatformData*
 129 mozilla::detail::MutexImpl::platformData() {
 130   static_assert(sizeof(platformData_) >= sizeof(PlatformData),
 131                 "platformData_ is too small");
 132   return reinterpret_cast<PlatformData*>(platformData_);
 133 }