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 <brianp@vmware.com>
Acked-by: Ian Romanick <ian.d.romanick@intel.com>
Acked-by: Chad Versace <chad.versace@linux.intel.com>

1 files changed, 346 insertions, 0 deletions

diff --git a/include/c11/threads_posix.h b/include/c11/threads_posix.h
new file mode 100644
index 0000000..463c93f
--- /dev/null
+++ b/include/c11/threads_posix.h
@@ -0,0 +1,346 @@
+/*
+ * 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 <stdlib.h>
+#include <assert.h>
+#include <limits.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sched.h>
+#include <stdint.h> /* for intptr_t */
+
+/*
+Configuration macro:
+
+  EMULATED_THREADS_USE_NATIVE_TIMEDLOCK
+    Use pthread_mutex_timedlock() for `mtx_timedlock()'
+    Otherwise use mtx_trylock() + *busy loop* emulation.
+*/
+#if !defined(__CYGWIN__)
+#define EMULATED_THREADS_USE_NATIVE_TIMEDLOCK
+#endif
+
+
+#include <pthread.h>
+
+/*---------------------------- macros ----------------------------*/
+#define ONCE_FLAG_INIT PTHREAD_ONCE_INIT
+#ifdef INIT_ONCE_STATIC_INIT
+#define TSS_DTOR_ITERATIONS PTHREAD_DESTRUCTOR_ITERATIONS
+#else
+#define TSS_DTOR_ITERATIONS 1  // assume TSS dtor MAY be called at least once.
+#endif
+
+// FIXME: temporary non-standard hack to ease transition
+#define _MTX_INITIALIZER_NP PTHREAD_MUTEX_INITIALIZER
+
+/*---------------------------- types ----------------------------*/
+typedef pthread_cond_t  cnd_t;
+typedef pthread_t       thrd_t;
+typedef pthread_key_t   tss_t;
+typedef pthread_mutex_t mtx_t;
+typedef pthread_once_t  once_flag;
+
+
+/*
+Implementation limits:
+  - Conditionally emulation for "mutex with timeout"
+    (see EMULATED_THREADS_USE_NATIVE_TIMEDLOCK macro)
+*/
+struct impl_thrd_param {
+    thrd_start_t func;
+    void *arg;
+};
+
+static inline void *
+impl_thrd_routine(void *p)
+{
+    struct impl_thrd_param pack = *((struct impl_thrd_param *)p);
+    free(p);
+    return (void*)(intptr_t)pack.func(pack.arg);
+}
+
+
+/*--------------- 7.25.2 Initialization functions ---------------*/
+// 7.25.2.1
+static inline void
+call_once(once_flag *flag, void (*func)(void))
+{
+    pthread_once(flag, func);
+}
+
+
+/*------------- 7.25.3 Condition variable functions -------------*/
+// 7.25.3.1
+static inline int
+cnd_broadcast(cnd_t *cond)
+{
+    if (!cond) return thrd_error;
+    pthread_cond_broadcast(cond);
+    return thrd_success;
+}
+
+// 7.25.3.2
+static inline void
+cnd_destroy(cnd_t *cond)
+{
+    assert(cond);
+    pthread_cond_destroy(cond);
+}
+
+// 7.25.3.3
+static inline int
+cnd_init(cnd_t *cond)
+{
+    if (!cond) return thrd_error;
+    pthread_cond_init(cond, NULL);
+    return thrd_success;
+}
+
+// 7.25.3.4
+static inline int
+cnd_signal(cnd_t *cond)
+{
+    if (!cond) return thrd_error;
+    pthread_cond_signal(cond);
+    return thrd_success;
+}
+
+// 7.25.3.5
+static inline int
+cnd_timedwait(cnd_t *cond, mtx_t *mtx, const xtime *xt)
+{
+    struct timespec abs_time;
+    int rt;
+    if (!cond || !mtx || !xt) return thrd_error;
+    rt = pthread_cond_timedwait(cond, mtx, &abs_time);
+    if (rt == ETIMEDOUT)
+        return thrd_busy;
+    return (rt == 0) ? thrd_success : thrd_error;
+}
+
+// 7.25.3.6
+static inline int
+cnd_wait(cnd_t *cond, mtx_t *mtx)
+{
+    if (!cond || !mtx) return thrd_error;
+    pthread_cond_wait(cond, mtx);
+    return thrd_success;
+}
+
+
+/*-------------------- 7.25.4 Mutex functions --------------------*/
+// 7.25.4.1
+static inline void
+mtx_destroy(mtx_t *mtx)
+{
+    assert(mtx);
+    pthread_mutex_destroy(mtx);
+}
+
+// 7.25.4.2
+static inline int
+mtx_init(mtx_t *mtx, int type)
+{
+    pthread_mutexattr_t attr;
+    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;
+    pthread_mutexattr_init(&attr);
+    if ((type & mtx_recursive) != 0) {
+#if defined(__linux__) || defined(__linux)
+        pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE_NP);
+#else
+        pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
+#endif
+    }
+    pthread_mutex_init(mtx, &attr);
+    pthread_mutexattr_destroy(&attr);
+    return thrd_success;
+}
+
+// 7.25.4.3
+static inline int
+mtx_lock(mtx_t *mtx)
+{
+    if (!mtx) return thrd_error;
+    pthread_mutex_lock(mtx);
+    return thrd_success;
+}
+
+// 7.25.4.4
+static inline int
+mtx_timedlock(mtx_t *mtx, const xtime *xt)
+{
+    if (!mtx || !xt) return thrd_error;
+    {
+#ifdef EMULATED_THREADS_USE_NATIVE_TIMEDLOCK
+    struct timespec ts;
+    int rt;
+    ts.tv_sec = xt->sec;
+    ts.tv_nsec = xt->nsec;
+    rt = pthread_mutex_timedlock(mtx, &ts);
+    if (rt == 0)
+        return thrd_success;
+    return (rt == ETIMEDOUT) ? thrd_busy : thrd_error;
+#else
+    time_t expire = time(NULL);
+    expire += xt->sec;
+    while (mtx_trylock(mtx) != thrd_success) {
+        time_t now = time(NULL);
+        if (expire < now)
+            return thrd_busy;
+        // busy loop!
+        thrd_yield();
+    }
+    return thrd_success;
+#endif
+    }
+}
+
+// 7.25.4.5
+static inline int
+mtx_trylock(mtx_t *mtx)
+{
+    if (!mtx) return thrd_error;
+    return (pthread_mutex_trylock(mtx) == 0) ? thrd_success : thrd_busy;
+}
+
+// 7.25.4.6
+static inline int
+mtx_unlock(mtx_t *mtx)
+{
+    if (!mtx) return thrd_error;
+    pthread_mutex_unlock(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;
+    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;
+    if (pthread_create(thr, NULL, impl_thrd_routine, pack) != 0) {
+        free(pack);
+        return thrd_error;
+    }
+    return thrd_success;
+}
+
+// 7.25.5.2
+static inline thrd_t
+thrd_current(void)
+{
+    return pthread_self();
+}
+
+// 7.25.5.3
+static inline int
+thrd_detach(thrd_t thr)
+{
+    return (pthread_detach(thr) == 0) ? thrd_success : thrd_error;
+}
+
+// 7.25.5.4
+static inline int
+thrd_equal(thrd_t thr0, thrd_t thr1)
+{
+    return pthread_equal(thr0, thr1);
+}
+
+// 7.25.5.5
+static inline void
+thrd_exit(int res)
+{
+    pthread_exit((void*)(intptr_t)res);
+}
+
+// 7.25.5.6
+static inline int
+thrd_join(thrd_t thr, int *res)
+{
+    void *code;
+    if (pthread_join(thr, &code) != 0)
+        return thrd_error;
+    if (res)
+        *res = (int)(intptr_t)code;
+    return thrd_success;
+}
+
+// 7.25.5.7
+static inline void
+thrd_sleep(const xtime *xt)
+{
+    struct timespec req;
+    assert(xt);
+    req.tv_sec = xt->sec;
+    req.tv_nsec = xt->nsec;
+    nanosleep(&req, NULL);
+}
+
+// 7.25.5.8
+static inline void
+thrd_yield(void)
+{
+    sched_yield();
+}
+
+
+/*----------- 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;
+    return (pthread_key_create(key, dtor) == 0) ? thrd_success : thrd_error;
+}
+
+// 7.25.6.2
+static inline void
+tss_delete(tss_t key)
+{
+    pthread_key_delete(key);
+}
+
+// 7.25.6.3
+static inline void *
+tss_get(tss_t key)
+{
+    return pthread_getspecific(key);
+}
+
+// 7.25.6.4
+static inline int
+tss_set(tss_t key, void *val)
+{
+    return (pthread_setspecific(key, val) == 0) ? 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;
+}