Replace pthread_self_ulong() with H5TS_thread_id(). The POSIX Threads

implementation ought to be portable to any system that has POSIX
Threads.  On Windows, I use the same API call as before.

6 files changed, 124 insertions, 21 deletions

diff --git a/src/H5CS.c b/src/H5CS.c
index 0a3dcce..f429d98 100644
--- a/src/H5CS.c
+++ b/src/H5CS.c
@@ -145,11 +145,7 @@ H5CS_print_stack(const H5CS_t *fstack, FILE *stream)
 
     HDfprintf(stream, "HDF5-DIAG: Function stack from %s ", H5_lib_vers_info_g);
     /* try show the process or thread id in multiple processes cases*/
-#ifdef H5_HAVE_THREADSAFE
-    HDfprintf(stream, "thread %lu.", HDpthread_self_ulong());
-#else  /* H5_HAVE_THREADSAFE */
-    HDfprintf(stream, "thread 0.");
-#endif  /* H5_HAVE_THREADSAFE */
+    HDfprintf(stream, "thread %lu.", H5TS_thread_id());
     if(fstack && fstack->nused>0)
         HDfprintf(stream, "  Back trace follows.");
     HDfputc('\n', stream);
diff --git a/src/H5Eint.c b/src/H5Eint.c
index e76db82..aba912e 100644
--- a/src/H5Eint.c
+++ b/src/H5Eint.c
@@ -259,10 +259,8 @@ H5E__walk1_cb(int n, H5E_error1_t *err_desc, void *client_data)
             else
                 HDfprintf(stream, "thread 0");
         } /* end block */
-#elif defined(H5_HAVE_THREADSAFE)
-        HDfprintf(stream, "thread %lu", (unsigned long)HDpthread_self_ulong());
 #else
-        HDfprintf(stream, "thread 0");
+        HDfprintf(stream, "thread %lu", H5TS_thread_id());
 #endif
         HDfprintf(stream, ":\n");
     } /* end if */
@@ -391,10 +389,8 @@ H5E__walk2_cb(unsigned n, const H5E_error2_t *err_desc, void *client_data)
             else
                 HDfprintf(stream, "thread 0");
         } /* end block */
-#elif defined(H5_HAVE_THREADSAFE)
-        HDfprintf(stream, "thread %lu", (unsigned long)HDpthread_self_ulong());
 #else
-        HDfprintf(stream, "thread 0");
+        HDfprintf(stream, "thread %lu", H5TS_thread_id());
 #endif
         HDfprintf(stream, ":\n");
     } /* end if */
diff --git a/src/H5TS.c b/src/H5TS.c
index 10e14d5..aa60eba 100644
--- a/src/H5TS.c
+++ b/src/H5TS.c
@@ -37,6 +37,31 @@ H5TS_key_t H5TS_funcstk_key_g;
 H5TS_key_t H5TS_apictx_key_g;
 H5TS_key_t H5TS_cancel_key_g;
 
+#ifndef H5_HAVE_WIN_THREADS
+
+/* An h5_tid_t is a record of a thread identifier that is
+ * available for reuse.
+ */
+struct _tid;
+typedef struct _tid h5_tid_t;
+
+struct _tid {
+    h5_tid_t *next;
+    unsigned long id;
+};
+
+/* Pointer to first free thread ID record or NULL. */
+static h5_tid_t *tid_next_free = NULL;
+static unsigned long tid_next_id = 0;
+
+/* Mutual exclusion for access to tid_next_free and tid_next_id. */
+static pthread_mutex_t tid_mtx;
+
+/* Key for thread-local storage of the thread ID. */
+static H5TS_key_t tid_key;
+
+#endif /* H5_HAVE_WIN_THREADS */
+
 
 /*--------------------------------------------------------------------------
  * NAME
@@ -68,6 +93,89 @@ H5TS_key_destructor(void *key_val)
 
 #ifndef H5_HAVE_WIN_THREADS
 
+/* When a thread shuts down, put its ID record on the free list. */
+static void
+tid_destructor(void *_v)
+{
+    h5_tid_t *tid = _v;
+
+    if (tid == NULL)
+        return;
+
+    /* XXX I can use mutexes in destructors, right? */
+    /* TBD use an atomic CAS */
+    pthread_mutex_lock(&tid_mtx);
+    tid->next = tid_next_free;
+    tid_next_free = tid;
+    pthread_mutex_unlock(&tid_mtx);
+}
+
+/* Initialize for integer thread identifiers. */
+static void
+tid_init(void)
+{
+    pthread_mutex_init(&tid_mtx, NULL);
+    pthread_key_create(&tid_key, tid_destructor);
+}
+
+/* Return an integer identifier, ID, for the current thread satisfies the
+ * following properties:
+ *
+ * 1 1 <= ID <= ULONG_MAX
+ * 2 The ID is constant over the thread's lifetime.
+ * 3 No two threads share an ID during their lifetimes.
+ * 4 A thread's ID is available for reuse as soon as it is joined.
+ *
+ * ID 0 is reserved.  H5TS_thread_id() returns 0 if the library was not built
+ * with thread safety or if an error prevents it from assigning an ID.
+ */
+unsigned long
+H5TS_thread_id(void)
+{
+    h5_tid_t *tid = pthread_getspecific(tid_key);
+    h5_tid_t proto_tid;
+
+    /* An ID is already assigned. */
+    if (tid != NULL)
+        return tid->id;
+
+    /* An ID is *not* already assigned: reuse an ID that's on the
+     * free list, or else generate a new ID.
+     * 
+     * Allocating memory while holding a mutex is bad form, so
+     * point `tid` at `proto_tid` if we need to allocate some
+     * memory.
+     */
+    pthread_mutex_lock(&tid_mtx);
+    if ((tid = tid_next_free) != NULL)
+        tid_next_free = tid->next;
+    else if (tid_next_id != ULONG_MAX) {
+        tid = &proto_tid;
+        tid->id = ++tid_next_id;
+    }
+    pthread_mutex_unlock(&tid_mtx);
+
+    /* If a prototype ID record was established, copy it to the heap. */
+    if (tid == &proto_tid) {
+        if ((tid = HDmalloc(sizeof(*tid))) != NULL)
+            *tid = proto_tid;
+    }
+
+    if (tid == NULL)
+        return 0;
+
+    /* Finish initializing the ID record and set a thread-local pointer
+     * to it.
+     */
+    tid->next = NULL;
+    if (pthread_setspecific(tid_key, tid) != 0) {
+        tid_destructor(tid);
+        return 0;
+    }
+
+    return tid->id;
+}
+
 /*--------------------------------------------------------------------------
  * NAME
  *    H5TS_pthread_first_thread_init
@@ -104,6 +212,9 @@ H5TS_pthread_first_thread_init(void)
     pthread_cond_init(&H5_g.init_lock.cond_var, NULL);
     H5_g.init_lock.lock_count = 0;
 
+    /* Initialize integer thread identifiers. */
+    tid_init();
+
     /* initialize key for thread-specific error stacks */
     pthread_key_create(&H5TS_errstk_key_g, H5TS_key_destructor);
 
@@ -528,5 +639,13 @@ H5TS_create_thread(void *(*func)(void *), H5TS_attr_t *attr, void *udata)
 
 } /* H5TS_create_thread */
 
+#else  /* H5_HAVE_THREADSAFE */
+
+unsigned long
+H5TS_thread_id(void)
+{
+    return 0;
+}
+
 #endif  /* H5_HAVE_THREADSAFE */
 
diff --git a/src/H5TSprivate.h b/src/H5TSprivate.h
index 9e093a6..76cf8f1 100644
--- a/src/H5TSprivate.h
+++ b/src/H5TSprivate.h
@@ -68,7 +68,7 @@ H5_DLL void H5TS_win32_process_exit(void);
 H5_DLL herr_t H5TS_win32_thread_enter(void);
 H5_DLL herr_t H5TS_win32_thread_exit(void);
 
-
+#define H5TS_thread_id() ((unsigned long)GetCurrentThreadId())
 
 #else /* H5_HAVE_WIN_THREADS */
 
@@ -102,6 +102,7 @@ typedef pthread_once_t H5TS_once_t;
 #define H5TS_mutex_init(mutex) pthread_mutex_init(mutex, NULL)
 #define H5TS_mutex_lock_simple(mutex) pthread_mutex_lock(mutex)
 #define H5TS_mutex_unlock_simple(mutex) pthread_mutex_unlock(mutex)
+H5_DLL unsigned long H5TS_thread_id(void);
 
 #endif /* H5_HAVE_WIN_THREADS */
 
diff --git a/src/H5private.h b/src/H5private.h
index 7ff0c87..e7626ac 100644
--- a/src/H5private.h
+++ b/src/H5private.h
@@ -1571,11 +1571,6 @@ extern char *strdup(const char *s);
     #define HDpthread_self()    pthread_self()
 #endif /* HDpthread_self */
 
-/* Use this version of pthread_self for printing the thread ID */
-#ifndef HDpthread_self_ulong
-    #define HDpthread_self_ulong()    ((unsigned long)pthread_self())
-#endif /* HDpthread_self_ulong */
-
 /* Macro for "stringizing" an integer in the C preprocessor (use H5_TOSTRING) */
 /* (use H5_TOSTRING, H5_STRINGIZE is just part of the implementation) */
 #define H5_STRINGIZE(x) #x
diff --git a/src/H5win32defs.h b/src/H5win32defs.h
index 0a0bd37..00df56d 100644
--- a/src/H5win32defs.h
+++ b/src/H5win32defs.h
@@ -163,10 +163,6 @@ extern "C" {
 
 /* Non-POSIX functions */
 
-/* Don't use actual pthread_self on Windows because the return
- * type cannot be cast as a ulong like other systems. */
-#define HDpthread_self_ulong() ((unsigned long)GetCurrentThreadId())
-
 #ifndef H5_HAVE_MINGW
 #define HDftruncate(F,L)    _chsize_s(F,L)
 #define HDfseek(F,O,W)      _fseeki64(F,O,W)