Reworking the build system

1 files changed, 342 insertions, 0 deletions

diff --git a/kit/threads.win32.c b/kit/threads.win32.c
new file mode 100644
index 0000000..ac185f7
--- /dev/null
+++ b/kit/threads.win32.c
@@ -0,0 +1,342 @@
+#include "threads.h"
+
+#ifndef KIT_DISABLE_SYSTEM_THREADS
+#  include "allocator.h"
+
+#  if defined(_WIN32) && !defined(__CYGWIN__)
+#    include <assert.h>
+#    include <errno.h>
+#    include <limits.h>
+#    include <process.h>
+#    include <stdlib.h>
+
+#    ifndef WIN32_LEAN_AND_MEAN
+#      define WIN32_LEAN_AND_MEAN 1
+#    endif
+#    ifndef NOMINMAX
+#      define NOMINMAX
+#    endif
+#    include <windows.h>
+
+/*
+Configuration macro:
+
+  EMULATED_THREADS_USE_NATIVE_CALL_ONCE
+    Use native WindowsAPI one-time initialization function.
+    (requires WinVista or later)
+    Otherwise emulate by mtx_trylock() + *busy loop* for WinXP.
+*/
+
+#    if _WIN32_WINNT >= 0x0600
+/* Prefer native WindowsAPI on newer environment. */
+#      if !defined(__MINGW32__)
+#        define EMULATED_THREADS_USE_NATIVE_CALL_ONCE
+#      endif
+#    endif
+
+/* check configuration */
+#    if defined(EMULATED_THREADS_USE_NATIVE_CALL_ONCE) && \
+        (_WIN32_WINNT < 0x0600)
+#      error EMULATED_THREADS_USE_NATIVE_CALL_ONCE requires _WIN32_WINNT>=0x0600
+#    endif
+
+static_assert(sizeof(cnd_t) == sizeof(CONDITION_VARIABLE),
+              "The size of cnd_t must equal to CONDITION_VARIABLE");
+static_assert(sizeof(thrd_t) == sizeof(HANDLE),
+              "The size of thrd_t must equal to HANDLE");
+static_assert(sizeof(mtx_t) == sizeof(CRITICAL_SECTION),
+              "The size of mtx_t must equal to CRITICAL_SECTION");
+static_assert(sizeof(once_flag) == sizeof(INIT_ONCE),
+              "The size of once_flag must equal to INIT_ONCE");
+
+/*
+Implementation limits:
+  - Conditionally emulation for "Initialization functions"
+    (see EMULATED_THREADS_USE_NATIVE_CALL_ONCE macro)
+  - Emulated `mtx_timelock()' with mtx_trylock() + *busy loop*
+*/
+
+typedef struct {
+  thrd_start_t func;
+  void        *arg;
+  thrd_t       thrd;
+} impl_thrd_param_t;
+
+struct thrd_state {
+  thrd_t thrd;
+  int    handle_need_close;
+};
+
+static thread_local struct thrd_state impl_current_thread = { 0 };
+
+static unsigned __stdcall impl_thrd_routine(void *p) {
+  impl_thrd_param_t *pack_p = (impl_thrd_param_t *) p;
+  impl_thrd_param_t  pack;
+  int                code;
+  impl_current_thread.thrd              = pack_p->thrd;
+  impl_current_thread.handle_need_close = 0;
+  memcpy(&pack, pack_p, sizeof(impl_thrd_param_t));
+  kit_alloc_dispatch(NULL, KIT_DEALLOCATE, 0, 0, p);
+  code = pack.func(pack.arg);
+  return (unsigned) code;
+}
+
+static time_t impl_timespec2msec(const struct timespec *ts) {
+  return (ts->tv_sec * 1000U) + (ts->tv_nsec / 1000000L);
+}
+
+static DWORD impl_abs2relmsec(const struct timespec *abs_time) {
+  const time_t    abs_ms = impl_timespec2msec(abs_time);
+  struct timespec now;
+  timespec_get(&now, TIME_UTC);
+  const time_t now_ms = impl_timespec2msec(&now);
+  const DWORD  rel_ms = (abs_ms > now_ms) ? (DWORD) (abs_ms - now_ms)
+                                          : 0;
+  return rel_ms;
+}
+
+#    ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
+struct impl_call_once_param {
+  void (*func)(void);
+};
+
+static BOOL CALLBACK impl_call_once_callback(PINIT_ONCE InitOnce,
+                                             PVOID      Parameter,
+                                             PVOID     *Context) {
+  struct impl_call_once_param *param = (struct impl_call_once_param *)
+      Parameter;
+  (param->func)();
+  ((void) InitOnce);
+  ((void) Context); /* suppress warning */
+  return TRUE;
+}
+#    endif /* ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE */
+
+void call_once(once_flag *flag, void (*func)(void)) {
+  assert(flag && func);
+#    ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
+  {
+    struct impl_call_once_param param;
+    param.func = func;
+    InitOnceExecuteOnce((PINIT_ONCE) flag, impl_call_once_callback,
+                        (PVOID) &param, NULL);
+  }
+#    else
+  if (InterlockedCompareExchangePointer(
+          (PVOID volatile *) &flag->status, (PVOID) 1, (PVOID) 0) ==
+      0) {
+    (func)();
+    InterlockedExchangePointer((PVOID volatile *) &flag->status,
+                               (PVOID) 2);
+  } else {
+    while (flag->status == 1) {
+      // busy loop!
+      thrd_yield();
+    }
+  }
+#    endif
+}
+
+int cnd_broadcast(cnd_t *cond) {
+  assert(cond != NULL);
+  WakeAllConditionVariable((PCONDITION_VARIABLE) cond);
+  return thrd_success;
+}
+
+void cnd_destroy(cnd_t *cond) {
+  assert(cond != NULL);
+  /* do nothing */
+  (void) cond;
+}
+
+int cnd_init(cnd_t *cond) {
+  assert(cond != NULL);
+  InitializeConditionVariable((PCONDITION_VARIABLE) cond);
+  return thrd_success;
+}
+
+int cnd_signal(cnd_t *cond) {
+  assert(cond != NULL);
+  WakeConditionVariable((PCONDITION_VARIABLE) cond);
+  return thrd_success;
+}
+
+int cnd_timedwait(cnd_t *cond, mtx_t *mtx,
+                  const struct timespec *abs_time) {
+  assert(cond != NULL);
+  assert(mtx != NULL);
+  assert(abs_time != NULL);
+  const DWORD timeout = impl_abs2relmsec(abs_time);
+  if (SleepConditionVariableCS((PCONDITION_VARIABLE) cond,
+                               (PCRITICAL_SECTION) mtx, timeout))
+    return thrd_success;
+  return (GetLastError() == ERROR_TIMEOUT) ? thrd_timedout
+                                           : thrd_error;
+}
+
+int cnd_wait(cnd_t *cond, mtx_t *mtx) {
+  assert(cond != NULL);
+  assert(mtx != NULL);
+  SleepConditionVariableCS((PCONDITION_VARIABLE) cond,
+                           (PCRITICAL_SECTION) mtx, INFINITE);
+  return thrd_success;
+}
+
+void mtx_destroy(mtx_t *mtx) {
+  assert(mtx);
+  DeleteCriticalSection((PCRITICAL_SECTION) mtx);
+}
+
+int mtx_init(mtx_t *mtx, int type) {
+  assert(mtx != NULL);
+  if (type != mtx_plain && type != mtx_timed &&
+      type != (mtx_plain | mtx_recursive) &&
+      type != (mtx_timed | mtx_recursive))
+    return thrd_error;
+  InitializeCriticalSection((PCRITICAL_SECTION) mtx);
+  return thrd_success;
+}
+
+int mtx_lock(mtx_t *mtx) {
+  assert(mtx != NULL);
+  EnterCriticalSection((PCRITICAL_SECTION) mtx);
+  return thrd_success;
+}
+
+int mtx_timedlock(mtx_t *mtx, const struct timespec *ts) {
+  assert(mtx != NULL);
+  assert(ts != NULL);
+  while (mtx_trylock(mtx) != thrd_success) {
+    if (impl_abs2relmsec(ts) == 0)
+      return thrd_timedout;
+    /* busy loop! */
+    thrd_yield();
+  }
+  return thrd_success;
+}
+
+int mtx_trylock(mtx_t *mtx) {
+  assert(mtx != NULL);
+  return TryEnterCriticalSection((PCRITICAL_SECTION) mtx)
+             ? thrd_success
+             : thrd_busy;
+}
+
+int mtx_unlock(mtx_t *mtx) {
+  assert(mtx != NULL);
+  LeaveCriticalSection((PCRITICAL_SECTION) mtx);
+  return thrd_success;
+}
+
+int thrd_create_with_stack(thrd_t *thr, thrd_start_t func, void *arg,
+                           ptrdiff_t const stack_size) {
+  impl_thrd_param_t *pack;
+  uintptr_t          handle;
+  assert(thr != NULL);
+  assert(stack_size >= 0 && stack_size < 0x100000000);
+
+  pack = (impl_thrd_param_t *) kit_alloc_dispatch(
+      NULL, KIT_ALLOCATE, (sizeof(impl_thrd_param_t)), 0, NULL);
+  if (!pack)
+    return thrd_nomem;
+  pack->func = func;
+  pack->arg  = arg;
+  handle     = _beginthreadex(NULL, (unsigned) stack_size,
+                              impl_thrd_routine, pack, CREATE_SUSPENDED,
+                              NULL);
+  if (handle == 0) {
+    kit_alloc_dispatch(NULL, KIT_DEALLOCATE, 0, 0, pack);
+    if (errno == EAGAIN || errno == EACCES)
+      return thrd_nomem;
+    return thrd_error;
+  }
+  thr->handle = (void *) handle;
+  pack->thrd  = *thr;
+  ResumeThread((HANDLE) handle);
+  return thrd_success;
+}
+
+int thrd_create(thrd_t *thr, thrd_start_t func, void *arg) {
+  return thrd_create_with_stack(thr, func, arg, 0);
+}
+
+thrd_t thrd_current(void) {
+  /* GetCurrentThread() returns a pseudo-handle, which we need
+   * to pass to DuplicateHandle(). Only the resulting handle can be
+   * used from other threads.
+   *
+   * Note that neither handle can be compared to the one by
+   * thread_create. Only the thread IDs - as returned by GetThreadId()
+   * and GetCurrentThreadId() can be compared directly.
+   *
+   * Other potential solutions would be:
+   * - define thrd_t as a thread Ids, but this would mean we'd need to
+   * OpenThread for many operations
+   * - use malloc'ed memory for thrd_t. This would imply using TLS for
+   * current thread.
+   *
+   * Neither is particularly nice.
+   *
+   * Life would be much easier if C11 threads had different
+   * abstractions for threads and thread IDs, just like C++11 threads
+   * does...
+   */
+  struct thrd_state *state = &impl_current_thread;
+  if (state->thrd.handle == NULL) {
+    if (!DuplicateHandle(GetCurrentProcess(), GetCurrentThread(),
+                         GetCurrentProcess(), &(state->thrd.handle),
+                         0, FALSE, DUPLICATE_SAME_ACCESS)) {
+      abort();
+    }
+    state->handle_need_close = 1;
+  }
+  return state->thrd;
+}
+
+int thrd_detach(thrd_t thr) {
+  CloseHandle(thr.handle);
+  return thrd_success;
+}
+
+int thrd_equal(thrd_t thr0, thrd_t thr1) {
+  return GetThreadId(thr0.handle) == GetThreadId(thr1.handle);
+}
+
+_Noreturn void thrd_exit(int res) {
+  _endthreadex((unsigned) res);
+}
+
+int thrd_join(thrd_t thr, int *res) {
+  DWORD w, code;
+  if (thr.handle == NULL) {
+    return thrd_error;
+  }
+  w = WaitForSingleObject(thr.handle, INFINITE);
+  if (w != WAIT_OBJECT_0)
+    return thrd_error;
+  if (res) {
+    if (!GetExitCodeThread(thr.handle, &code)) {
+      CloseHandle(thr.handle);
+      return thrd_error;
+    }
+    *res = (int) code;
+  }
+  CloseHandle(thr.handle);
+  return thrd_success;
+}
+
+int thrd_sleep(const struct timespec *time_point,
+               struct timespec       *remaining) {
+  (void) remaining;
+  assert(time_point);
+  assert(!remaining); /* not implemented */
+  Sleep((DWORD) impl_timespec2msec(time_point));
+  return 0;
+}
+
+void thrd_yield(void) {
+  SwitchToThread();
+}
+
+#  endif
+#endif