c11: Import threads.h emulation library.

Implementation is based of https://gist.github.com/2223710 with the
following modifications:
- inline implementatation
- retain XP compatability
- add temporary hack for static mutex initializers (as they are not part
  of the stack but still widely used internally)
- make TIME_UTC a conditional macro (some system headers already define
  it, so this prevents conflict)
- respect HAVE_PTHREAD macro

Reviewed-by: Brian Paul <[email protected]>
Acked-by: Ian Romanick <[email protected]>
Acked-by: Chad Versace <[email protected]>

1 files changed, 588 insertions, 0 deletions

diff --git a/include/c11/threads_win32.h b/include/c11/threads_win32.h
new file mode 100644
index 00000000000..5a63e90b3a7
--- /dev/null
+++ b/include/c11/threads_win32.h
@@ -0,0 +1,588 @@
+/*
+ * C11 <threads.h> emulation library
+ *
+ * (C) Copyright yohhoy 2012.
+ * Distributed under the Boost Software License, Version 1.0.
+ * (See copy at http://www.boost.org/LICENSE_1_0.txt)
+ */
+#include <assert.h>
+#include <limits.h>
+#include <errno.h>
+#include <process.h>  // MSVCRT
+
+/*
+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.
+
+  EMULATED_THREADS_USE_NATIVE_CV
+    Use native WindowsAPI condition variable object.
+    (requires WinVista or later)
+    Otherwise use emulated implementation for WinXP.
+
+  EMULATED_THREADS_TSS_DTOR_SLOTNUM
+    Max registerable TSS dtor number.
+*/
+
+// XXX: Retain XP compatability
+#if 0
+#if _WIN32_WINNT >= 0x0600
+// Prefer native WindowsAPI on newer environment.
+#if !defined(__MINGW32__)
+#define EMULATED_THREADS_USE_NATIVE_CALL_ONCE 
+#endif
+#define EMULATED_THREADS_USE_NATIVE_CV
+#endif
+#endif
+#define EMULATED_THREADS_TSS_DTOR_SLOTNUM 64  // see TLS_MINIMUM_AVAILABLE
+
+
+#include <windows.h>
+
+// 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
+
+#if defined(EMULATED_THREADS_USE_NATIVE_CV) && (_WIN32_WINNT < 0x0600)
+#error EMULATED_THREADS_USE_NATIVE_CV requires _WIN32_WINNT>=0x0600
+#endif
+
+
+/*---------------------------- macros ----------------------------*/
+#ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
+#define ONCE_FLAG_INIT INIT_ONCE_STATIC_INIT
+#else
+#define ONCE_FLAG_INIT {0}
+#endif
+#define TSS_DTOR_ITERATIONS 1
+
+// FIXME: temporary non-standard hack to ease transition
+#define _MTX_INITIALIZER_NP {(PCRITICAL_SECTION_DEBUG)-1, -1, 0, 0, 0, 0}
+
+/*---------------------------- types ----------------------------*/
+typedef struct cnd_t {
+#ifdef EMULATED_THREADS_USE_NATIVE_CV
+    CONDITION_VARIABLE condvar;
+#else
+    int blocked;
+    int gone;
+    int to_unblock;
+    HANDLE sem_queue;
+    HANDLE sem_gate;
+    CRITICAL_SECTION monitor;
+#endif
+} cnd_t;
+
+typedef HANDLE thrd_t;
+
+typedef DWORD tss_t;
+
+typedef CRITICAL_SECTION mtx_t;
+
+#ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
+typedef INIT_ONCE once_flag;
+#else
+typedef struct once_flag_t {
+    volatile LONG status;
+} once_flag;
+#endif
+
+
+static inline void * tss_get(tss_t key);
+static inline void thrd_yield(void);
+static inline int mtx_trylock(mtx_t *mtx);
+static inline int mtx_lock(mtx_t *mtx);
+static inline int mtx_unlock(mtx_t *mtx);
+
+/*
+Implementation limits:
+  - Conditionally emulation for "Initialization functions"
+    (see EMULATED_THREADS_USE_NATIVE_CALL_ONCE macro)
+  - Emulated `mtx_timelock()' with mtx_trylock() + *busy loop*
+*/
+static void impl_tss_dtor_invoke(void);  // forward decl.
+
+struct impl_thrd_param {
+    thrd_start_t func;
+    void *arg;
+};
+
+static unsigned __stdcall impl_thrd_routine(void *p)
+{
+    struct impl_thrd_param pack;
+    int code;
+    memcpy(&pack, p, sizeof(struct impl_thrd_param));
+    free(p);
+    code = pack.func(pack.arg);
+    impl_tss_dtor_invoke();
+    return (unsigned)code;
+}
+
+static DWORD impl_xtime2msec(const xtime *xt)
+{
+    return (DWORD)((xt->sec * 1000u) + (xt->nsec / 1000));
+}
+
+#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
+
+#ifndef EMULATED_THREADS_USE_NATIVE_CV
+/*
+Note:
+  The implementation of condition variable is ported from Boost.Interprocess
+  See http://www.boost.org/boost/interprocess/sync/windows/condition.hpp
+*/
+static void impl_cond_do_signal(cnd_t *cond, int broadcast)
+{
+    int nsignal = 0;
+
+    EnterCriticalSection(&cond->monitor);
+    if (cond->to_unblock != 0) {
+        if (cond->blocked == 0) {
+            LeaveCriticalSection(&cond->monitor);
+            return;
+        }
+        if (broadcast) {
+            cond->to_unblock += nsignal = cond->blocked;
+            cond->blocked = 0;
+        } else {
+            nsignal = 1;
+            cond->to_unblock++;
+            cond->blocked--;
+        }
+    } else if (cond->blocked > cond->gone) {
+        WaitForSingleObject(cond->sem_gate, INFINITE);
+        if (cond->gone != 0) {
+            cond->blocked -= cond->gone;
+            cond->gone = 0;
+        }
+        if (broadcast) {
+            nsignal = cond->to_unblock = cond->blocked;
+            cond->blocked = 0;
+        } else {
+            nsignal = cond->to_unblock = 1;
+            cond->blocked--;
+        }
+    }
+    LeaveCriticalSection(&cond->monitor);
+
+    if (0 < nsignal)
+        ReleaseSemaphore(cond->sem_queue, nsignal, NULL);
+}
+
+static int impl_cond_do_wait(cnd_t *cond, mtx_t *mtx, const xtime *xt)
+{
+    int nleft = 0;
+    int ngone = 0;
+    int timeout = 0;
+    DWORD w;
+
+    WaitForSingleObject(cond->sem_gate, INFINITE);
+    cond->blocked++;
+    ReleaseSemaphore(cond->sem_gate, 1, NULL);
+
+    mtx_unlock(mtx);
+
+    w = WaitForSingleObject(cond->sem_queue, xt ? impl_xtime2msec(xt) : INFINITE);
+    timeout = (w == WAIT_TIMEOUT);
+ 
+    EnterCriticalSection(&cond->monitor);
+    if ((nleft = cond->to_unblock) != 0) {
+        if (timeout) {
+            if (cond->blocked != 0) {
+                cond->blocked--;
+            } else {
+                cond->gone++;
+            }
+        }
+        if (--cond->to_unblock == 0) {
+            if (cond->blocked != 0) {
+                ReleaseSemaphore(cond->sem_gate, 1, NULL);
+                nleft = 0;
+            }
+            else if ((ngone = cond->gone) != 0) {
+                cond->gone = 0;
+            }
+        }
+    } else if (++cond->gone == INT_MAX/2) {
+        WaitForSingleObject(cond->sem_gate, INFINITE);
+        cond->blocked -= cond->gone;
+        ReleaseSemaphore(cond->sem_gate, 1, NULL);
+        cond->gone = 0;
+    }
+    LeaveCriticalSection(&cond->monitor);
+
+    if (nleft == 1) {
+        while (ngone--)
+            WaitForSingleObject(cond->sem_queue, INFINITE);
+        ReleaseSemaphore(cond->sem_gate, 1, NULL);
+    }
+
+    mtx_lock(mtx);
+    return timeout ? thrd_busy : thrd_success;
+}
+#endif  // ifndef EMULATED_THREADS_USE_NATIVE_CV
+
+static struct impl_tss_dtor_entry {
+    tss_t key;
+    tss_dtor_t dtor;
+} impl_tss_dtor_tbl[EMULATED_THREADS_TSS_DTOR_SLOTNUM];
+
+static int impl_tss_dtor_register(tss_t key, tss_dtor_t dtor)
+{
+    int i;
+    for (i = 0; i < EMULATED_THREADS_TSS_DTOR_SLOTNUM; i++) {
+        if (!impl_tss_dtor_tbl[i].dtor)
+            break;
+    }
+    if (i == EMULATED_THREADS_TSS_DTOR_SLOTNUM)
+        return 1;
+    impl_tss_dtor_tbl[i].key = key;
+    impl_tss_dtor_tbl[i].dtor = dtor;
+    return 0;
+}
+
+static void impl_tss_dtor_invoke()
+{
+    int i;
+    for (i = 0; i < EMULATED_THREADS_TSS_DTOR_SLOTNUM; i++) {
+        if (impl_tss_dtor_tbl[i].dtor) {
+            void* val = tss_get(impl_tss_dtor_tbl[i].key);
+            if (val)
+                (impl_tss_dtor_tbl[i].dtor)(val);
+        }
+    }
+}
+
+
+/*--------------- 7.25.2 Initialization functions ---------------*/
+// 7.25.2.1
+static inline 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(flag, impl_call_once_callback, (PVOID)&param, NULL);
+    }
+#else
+    if (InterlockedCompareExchange(&flag->status, 1, 0) == 0) {
+        (func)();
+        InterlockedExchange(&flag->status, 2);
+    } else {
+        while (flag->status == 1) {
+            // busy loop!
+            thrd_yield();
+        }
+    }
+#endif
+}
+
+
+/*------------- 7.25.3 Condition variable functions -------------*/
+// 7.25.3.1
+static inline int
+cnd_broadcast(cnd_t *cond)
+{
+    if (!cond) return thrd_error;
+#ifdef EMULATED_THREADS_USE_NATIVE_CV
+    WakeAllConditionVariable(&cond->condvar);
+#else
+    impl_cond_do_signal(cond, 1);
+#endif
+    return thrd_success;
+}
+
+// 7.25.3.2
+static inline void
+cnd_destroy(cnd_t *cond)
+{
+    assert(cond);
+#ifdef EMULATED_THREADS_USE_NATIVE_CV
+    // do nothing
+#else
+    CloseHandle(cond->sem_queue);
+    CloseHandle(cond->sem_gate);
+    DeleteCriticalSection(&cond->monitor);
+#endif
+}
+
+// 7.25.3.3
+static inline int
+cnd_init(cnd_t *cond)
+{
+    if (!cond) return thrd_error;
+#ifdef EMULATED_THREADS_USE_NATIVE_CV
+    InitializeConditionVariable(&cond->condvar);
+#else
+    cond->blocked = 0;
+    cond->gone = 0;
+    cond->to_unblock = 0;
+    cond->sem_queue = CreateSemaphore(NULL, 0, LONG_MAX, NULL);
+    cond->sem_gate = CreateSemaphore(NULL, 1, 1, NULL);
+    InitializeCriticalSection(&cond->monitor);
+#endif
+    return thrd_success;
+}
+
+// 7.25.3.4
+static inline int
+cnd_signal(cnd_t *cond)
+{
+    if (!cond) return thrd_error;
+#ifdef EMULATED_THREADS_USE_NATIVE_CV
+    WakeConditionVariable(&cond->condvar);
+#else
+    impl_cond_do_signal(cond, 0);
+#endif
+    return thrd_success;
+}
+
+// 7.25.3.5
+static inline int
+cnd_timedwait(cnd_t *cond, mtx_t *mtx, const xtime *xt)
+{
+    if (!cond || !mtx || !xt) return thrd_error;
+#ifdef EMULATED_THREADS_USE_NATIVE_CV
+    if (SleepConditionVariableCS(&cond->condvar, mtx, impl_xtime2msec(xt)))
+        return thrd_success;
+    return (GetLastError() == ERROR_TIMEOUT) ? thrd_busy : thrd_error;
+#else
+    return impl_cond_do_wait(cond, mtx, xt);
+#endif
+}
+
+// 7.25.3.6
+static inline int
+cnd_wait(cnd_t *cond, mtx_t *mtx)
+{
+    if (!cond || !mtx) return thrd_error;
+#ifdef EMULATED_THREADS_USE_NATIVE_CV
+    SleepConditionVariableCS(&cond->condvar, mtx, INFINITE);
+#else
+    impl_cond_do_wait(cond, mtx, NULL);
+#endif
+    return thrd_success;
+}
+
+
+/*-------------------- 7.25.4 Mutex functions --------------------*/
+// 7.25.4.1
+static inline void
+mtx_destroy(mtx_t *mtx)
+{
+    assert(mtx);
+    DeleteCriticalSection(mtx);
+}
+
+// 7.25.4.2
+static inline int
+mtx_init(mtx_t *mtx, int type)
+{
+    if (!mtx) return thrd_error;
+    if (type != mtx_plain && type != mtx_timed && type != mtx_try
+      && type != (mtx_plain|mtx_recursive)
+      && type != (mtx_timed|mtx_recursive)
+      && type != (mtx_try|mtx_recursive))
+        return thrd_error;
+    InitializeCriticalSection(mtx);
+    return thrd_success;
+}
+
+// 7.25.4.3
+static inline int
+mtx_lock(mtx_t *mtx)
+{
+    if (!mtx) return thrd_error;
+    EnterCriticalSection(mtx);
+    return thrd_success;
+}
+
+// 7.25.4.4
+static inline int
+mtx_timedlock(mtx_t *mtx, const xtime *xt)
+{
+    time_t expire, now;
+    if (!mtx || !xt) return thrd_error;
+    expire = time(NULL);
+    expire += xt->sec;
+    while (mtx_trylock(mtx) != thrd_success) {
+        now = time(NULL);
+        if (expire < now)
+            return thrd_busy;
+        // busy loop!
+        thrd_yield();
+    }
+    return thrd_success;
+}
+
+// 7.25.4.5
+static inline int
+mtx_trylock(mtx_t *mtx)
+{
+    if (!mtx) return thrd_error;
+    return TryEnterCriticalSection(mtx) ? thrd_success : thrd_busy;
+}
+
+// 7.25.4.6
+static inline int
+mtx_unlock(mtx_t *mtx)
+{
+    if (!mtx) return thrd_error;
+    LeaveCriticalSection(mtx);
+    return thrd_success;
+}
+
+
+/*------------------- 7.25.5 Thread functions -------------------*/
+// 7.25.5.1
+static inline int
+thrd_create(thrd_t *thr, thrd_start_t func, void *arg)
+{
+    struct impl_thrd_param *pack;
+    uintptr_t handle;
+    if (!thr) return thrd_error;
+    pack = (struct impl_thrd_param *)malloc(sizeof(struct impl_thrd_param));
+    if (!pack) return thrd_nomem;
+    pack->func = func;
+    pack->arg = arg;
+    handle = _beginthreadex(NULL, 0, impl_thrd_routine, pack, 0, NULL);
+    if (handle == 0) {
+        if (errno == EAGAIN || errno == EACCES)
+            return thrd_nomem;
+        return thrd_error;
+    }
+    *thr = (thrd_t)handle;
+    return thrd_success;
+}
+
+// 7.25.5.2
+static inline thrd_t
+thrd_current(void)
+{
+    return GetCurrentThread();
+}
+
+// 7.25.5.3
+static inline int
+thrd_detach(thrd_t thr)
+{
+    CloseHandle(thr);
+    return thrd_success;
+}
+
+// 7.25.5.4
+static inline int
+thrd_equal(thrd_t thr0, thrd_t thr1)
+{
+    return (thr0 == thr1);
+}
+
+// 7.25.5.5
+static inline void
+thrd_exit(int res)
+{
+    impl_tss_dtor_invoke();
+    _endthreadex((unsigned)res);
+}
+
+// 7.25.5.6
+static inline int
+thrd_join(thrd_t thr, int *res)
+{
+    DWORD w, code;
+    w = WaitForSingleObject(thr, INFINITE);
+    if (w != WAIT_OBJECT_0)
+        return thrd_error;
+    if (res) {
+        if (!GetExitCodeThread(thr, &code)) {
+            CloseHandle(thr);
+            return thrd_error;
+        }
+        *res = (int)code;
+    }
+    CloseHandle(thr);
+    return thrd_success;
+}
+
+// 7.25.5.7
+static inline void
+thrd_sleep(const xtime *xt)
+{
+    assert(xt);
+    Sleep(impl_xtime2msec(xt));
+}
+
+// 7.25.5.8
+static inline void
+thrd_yield(void)
+{
+    SwitchToThread();
+}
+
+
+/*----------- 7.25.6 Thread-specific storage functions -----------*/
+// 7.25.6.1
+static inline int
+tss_create(tss_t *key, tss_dtor_t dtor)
+{
+    if (!key) return thrd_error;
+    *key = TlsAlloc();
+    if (dtor) {
+        if (impl_tss_dtor_register(*key, dtor)) {
+            TlsFree(*key);
+            return thrd_error;
+        }
+    }
+    return (*key != 0xFFFFFFFF) ? thrd_success : thrd_error;
+}
+
+// 7.25.6.2
+static inline void
+tss_delete(tss_t key)
+{
+    TlsFree(key);
+}
+
+// 7.25.6.3
+static inline void *
+tss_get(tss_t key)
+{
+    return TlsGetValue(key);
+}
+
+// 7.25.6.4
+static inline int
+tss_set(tss_t key, void *val)
+{
+    return TlsSetValue(key, val) ? thrd_success : thrd_error;
+}
+
+
+/*-------------------- 7.25.7 Time functions --------------------*/
+// 7.25.6.1
+static inline int
+xtime_get(xtime *xt, int base)
+{
+    if (!xt) return 0;
+    if (base == TIME_UTC) {
+        xt->sec = time(NULL);
+        xt->nsec = 0;
+        return base;
+    }
+    return 0;
+}