1 files changed, 186 insertions, 0 deletions
diff --git a/c_src/nif_helpers.c b/c_src/nif_helpers.c
new file mode 100644
index 0000000..820fef8
--- /dev/null
+++ b/c_src/nif_helpers.c
@@ -0,0 +1,186 @@
+// Copyright (c) 2014, Loïc Hoguin <[email protected]>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+#include "nif_helpers.h"
+#include <sys/queue.h>
+#include <stdarg.h>
+
+extern atom_ok;
+extern atom__nif_thread_ret_;
+
+typedef struct nif_thread_message {
+	TAILQ_ENTRY(nif_thread_message) next_entry;
+
+	ErlNifPid* from_pid;
+	void* function;
+	nif_thread_arg* args;
+} nif_thread_message;
+
+typedef TAILQ_HEAD(nif_thread_mailbox, nif_thread_message) nif_thread_mailbox;
+
+typedef struct {
+	ErlNifTid tid;
+	ErlNifMutex* lock;
+	ErlNifCond* cond;
+	nif_thread_mailbox* mailbox;
+} nif_thread_state;
+
+// Message.
+
+nif_thread_message* nif_thread_message_alloc(void* f, nif_thread_arg* args, ErlNifPid* pid)
+{
+	nif_thread_message* msg = (nif_thread_message*)enif_alloc(sizeof(nif_thread_message));
+
+	msg->from_pid = pid;
+	msg->function = f;
+	msg->args = args;
+
+	return msg;
+}
+
+void nif_thread_message_free(nif_thread_message* msg)
+{
+	enif_free(msg->from_pid);
+	enif_free(msg->args);
+	enif_free(msg);
+}
+
+// Calls and casts.
+
+ERL_NIF_TERM nif_thread_send(nif_thread_state* st, nif_thread_message* msg)
+{
+	enif_mutex_lock(st->lock);
+
+	TAILQ_INSERT_TAIL(st->mailbox, msg, next_entry);
+
+	enif_cond_signal(st->cond);
+	enif_mutex_unlock(st->lock);
+
+	return atom_ok;
+}
+
+ERL_NIF_TERM nif_thread_cast(ErlNifEnv* env, void (*f)(nif_thread_arg*), int a, ...)
+{
+	va_list ap;
+	int i;
+
+	nif_thread_arg* args = (nif_thread_arg*)enif_alloc(a * sizeof(nif_thread_arg));
+
+	va_start(ap, a);
+	for (i = 0; i < a; i++)
+		args[i] = va_arg(ap, void*);
+	va_end(ap);
+
+	nif_thread_message* msg = nif_thread_message_alloc(f, args, NULL);
+
+	return nif_thread_send((nif_thread_state*)enif_priv_data(env), msg);
+}
+
+ERL_NIF_TERM nif_thread_call(ErlNifEnv* env, ERL_NIF_TERM (*f)(ErlNifEnv*, nif_thread_arg*), int a, ...)
+{
+	va_list ap;
+	int i;
+
+	nif_thread_arg* args = (nif_thread_arg*)enif_alloc(a * sizeof(nif_thread_arg));
+
+	va_start(ap, a);
+	for (i = 0; i < a; i++)
+		args[i] = va_arg(ap, void*);
+	va_end(ap);
+
+	ErlNifPid* pid = (ErlNifPid*)enif_alloc(sizeof(ErlNifPid));
+	nif_thread_message* msg = nif_thread_message_alloc((void*)f, args, enif_self(env, pid));
+
+	return nif_thread_send((nif_thread_state*)enif_priv_data(env), msg);
+}
+
+// Main thread loop.
+
+int nif_thread_receive(nif_thread_state* st, nif_thread_message** msg)
+{
+	enif_mutex_lock(st->lock);
+
+	while (TAILQ_EMPTY(st->mailbox))
+		enif_cond_wait(st->cond, st->lock);
+
+	*msg = TAILQ_FIRST(st->mailbox);
+	TAILQ_REMOVE(st->mailbox, TAILQ_FIRST(st->mailbox), next_entry);
+
+	enif_mutex_unlock(st->lock);
+
+	if ((*msg)->function == NULL)
+		return 0;
+
+	return 1;
+}
+
+void nif_thread_handle(ErlNifEnv* env, nif_thread_state* st, nif_thread_message* msg)
+{
+	if (msg->from_pid == NULL) {
+		void (*cast)(nif_thread_arg*) = msg->function;
+		cast(msg->args);
+	} else {
+		ERL_NIF_TERM (*call)(ErlNifEnv*, nif_thread_arg*) = msg->function;
+		ERL_NIF_TERM ret = call(env, msg->args);
+
+		enif_send(NULL, msg->from_pid, env,
+			enif_make_tuple2(env, atom__nif_thread_ret_, ret));
+
+		enif_clear_env(env);
+	}
+
+	nif_thread_message_free(msg);
+}
+
+void* nif_main_thread(void* obj)
+{
+	ErlNifEnv* env = enif_alloc_env();
+	nif_thread_state* st = (nif_thread_state*)obj;
+	nif_thread_message* msg;
+
+	while (nif_thread_receive(st, &msg))
+		nif_thread_handle(env, st, msg);
+
+	return NULL;
+}
+
+// Main thread creation/destruction.
+
+void* nif_create_main_thread(char* name)
+{
+	nif_thread_state* st = (nif_thread_state*)enif_alloc(sizeof(nif_thread_state));
+
+	st->lock = enif_mutex_create("esdl2_lock");
+	st->cond = enif_cond_create("esdl2_cond");
+	st->mailbox = (nif_thread_mailbox*)enif_alloc(sizeof(nif_thread_mailbox));
+	TAILQ_INIT(st->mailbox);
+
+	enif_thread_create(name, &(st->tid), nif_main_thread, st, NULL);
+
+	return (void*)st;
+}
+
+void nif_destroy_main_thread(void* void_st)
+{
+	nif_thread_state* st = (nif_thread_state*)void_st;
+	nif_thread_message* msg = nif_thread_message_alloc(NULL, NULL, NULL);
+
+	nif_thread_send(st, msg);
+	enif_thread_join(st->tid, NULL);
+
+	enif_cond_destroy(st->cond);
+	enif_mutex_destroy(st->lock);
+	enif_free(st->mailbox);
+	enif_free(st);
+}