From 96f113c40d4934a98aed30a64851feec891a688a Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Tue, 10 May 2022 10:33:34 +0200
Subject: Use our own implementation of C++14 threads on MinGW

---
 libbuild2/scheduler.hxx      | 22 +++++++++---------
 libbuild2/scheduler.test.cxx |  1 -
 libbuild2/types.hxx          | 53 ++++++++++++++++++++++++++++++++------------
 3 files changed, 49 insertions(+), 27 deletions(-)

diff --git a/libbuild2/scheduler.hxx b/libbuild2/scheduler.hxx
index 76b3263..dc18859 100644
--- a/libbuild2/scheduler.hxx
+++ b/libbuild2/scheduler.hxx
@@ -5,11 +5,9 @@
 #define LIBBUILD2_SCHEDULER_HXX
 
 #include <list>
-#include <mutex>
 #include <tuple>
 #include <atomic>
 #include <type_traits>        // aligned_storage, etc
-#include <condition_variable>
 
 #include <libbuild2/types.hxx>
 #include <libbuild2/utility.hxx>
@@ -492,7 +490,7 @@ namespace build2
     static size_t
     hardware_concurrency ()
     {
-      return std::thread::hardware_concurrency ();
+      return build2::thread::hardware_concurrency ();
     }
 
     // Return a prime number that can be used as a lock shard size that's
@@ -509,7 +507,7 @@ namespace build2
     // to become idle. Return the lock over the scheduler mutex. Normally you
     // don't need to call this function directly.
     //
-    using lock = std::unique_lock<std::mutex>;
+    using lock = build2::mlock;
 
     lock
     wait_idle ();
@@ -571,7 +569,7 @@ namespace build2
     size_t                     monitor_init_;             // Initial count.
     function<size_t (size_t)>  monitor_func_;
 
-    std::mutex mutex_;
+    build2::mutex mutex_;
     bool shutdown_ = true;  // Shutdown flag.
 
     optional<size_t> max_stack_;
@@ -611,8 +609,8 @@ namespace build2
     //
     size_t orig_max_active_ = 0;
 
-    std::condition_variable idle_condv_;  // Idle helpers queue.
-    std::condition_variable ready_condv_; // Ready masters queue.
+    build2::condition_variable idle_condv_;  // Idle helpers queue.
+    build2::condition_variable ready_condv_; // Ready masters queue.
 
     // Statistics counters.
     //
@@ -631,8 +629,8 @@ namespace build2
 
     // Deadlock detection.
     //
-    std::thread             dead_thread_;
-    std::condition_variable dead_condv_;
+    build2::thread             dead_thread_;
+    build2::condition_variable dead_condv_;
 
     static void*
     deadlock_monitor (void*);
@@ -653,8 +651,8 @@ namespace build2
     //
     struct wait_slot
     {
-      std::mutex mutex;
-      std::condition_variable condv;
+      build2::mutex mutex;
+      build2::condition_variable condv;
       size_t waiters = 0;
       const atomic_count* task_count;
       bool shutdown = true;
@@ -726,7 +724,7 @@ namespace build2
 
     struct task_queue: task_queue_data
     {
-      std::mutex mutex;
+      build2::mutex mutex;
       bool shutdown = false;
 
       size_t stat_full = 0; // Number of times push() returned NULL.
diff --git a/libbuild2/scheduler.test.cxx b/libbuild2/scheduler.test.cxx
index b29c932..2ef8d5c 100644
--- a/libbuild2/scheduler.test.cxx
+++ b/libbuild2/scheduler.test.cxx
@@ -2,7 +2,6 @@
 // license   : MIT; see accompanying LICENSE file
 
 #include <chrono>
-#include <thread>
 
 #include <iostream>
 
diff --git a/libbuild2/types.hxx b/libbuild2/types.hxx
index cd6fdd8..c260aeb 100644
--- a/libbuild2/types.hxx
+++ b/libbuild2/types.hxx
@@ -29,14 +29,22 @@
 #include <functional>       // hash, function, reference_wrapper
 #include <initializer_list>
 
-#include <mutex>
 #include <atomic>
-#include <thread>
-#include <condition_variable>
 
-#include <libbutl/ft/shared_mutex.hxx>
-#if defined(__cpp_lib_shared_mutex) || defined(__cpp_lib_shared_timed_mutex)
-#  include <shared_mutex>
+#ifndef LIBBUTL_MINGW_STDTHREAD
+#  include <mutex>
+#  include <thread>
+#  include <condition_variable>
+
+#  include <libbutl/ft/shared_mutex.hxx>
+#  if defined(__cpp_lib_shared_mutex) || defined(__cpp_lib_shared_timed_mutex)
+#    include <shared_mutex>
+#  endif
+#else
+#  include <libbutl/mingw-mutex.hxx>
+#  include <libbutl/mingw-thread.hxx>
+#  include <libbutl/mingw-condition_variable.hxx>
+#  include <libbutl/mingw-shared_mutex.hxx>
 #endif
 
 #include <ios>           // ios_base::failure
@@ -189,20 +197,27 @@ namespace build2
   }
 #endif
 
+#ifndef LIBBUTL_MINGW_STDTHREAD
   using std::mutex;
   using mlock = std::unique_lock<mutex>;
 
   using std::condition_variable;
 
-#if   defined(__cpp_lib_shared_mutex)
+  using std::defer_lock;
+  using std::adopt_lock;
+
+  using std::thread;
+  namespace this_thread = std::this_thread;
+
+#  if   defined(__cpp_lib_shared_mutex)
   using shared_mutex = std::shared_mutex;
   using ulock        = std::unique_lock<shared_mutex>;
   using slock        = std::shared_lock<shared_mutex>;
-#elif defined(__cpp_lib_shared_timed_mutex)
+#  elif defined(__cpp_lib_shared_timed_mutex)
   using shared_mutex = std::shared_timed_mutex;
   using ulock        = std::unique_lock<shared_mutex>;
   using slock        = std::shared_lock<shared_mutex>;
-#else
+#  else
   // Because we have this fallback, we need to be careful not to create
   // multiple shared locks in the same thread.
   //
@@ -217,13 +232,23 @@ namespace build2
 
   using ulock        = std::unique_lock<shared_mutex>;
   using slock        = ulock;
-#endif
+#  endif
+#else // LIBBUTL_MINGW_STDTHREAD
+  using mingw_stdthread::mutex;
+  using mlock = mingw_stdthread::unique_lock<mutex>;
 
-  using std::defer_lock;
-  using std::adopt_lock;
+  using mingw_stdthread::condition_variable;
 
-  using std::thread;
-  namespace this_thread = std::this_thread;
+  using mingw_stdthread::defer_lock;
+  using mingw_stdthread::adopt_lock;
+
+  using mingw_stdthread::thread;
+  namespace this_thread = mingw_stdthread::this_thread;
+
+  using shared_mutex = mingw_stdthread::shared_mutex;
+  using ulock        = mingw_stdthread::unique_lock<shared_mutex>;
+  using slock        = mingw_stdthread::shared_lock<shared_mutex>;
+#endif
 
   // Global, MT-safe information cache. Normally used for caching information
   // (versions, target triplets, search paths, etc) extracted from other
-- 
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