Merge branch 'ev_execute'

CHANGELOG.md

@@ -3,6 +3,7 @@ All notable changes to this project will be documented in this file.
 
 ## Unreleased - ???
 - Add `dflt` argument to find-index.
+- Deprecate `file/popen` in favor of `os/spawn`.
 - Add `:all` keyword to `ev/read` and `net/read` to make them more like `file/read`. However, we
   do not provide any `:line` option as that requires buffering.
 - Change repl behavior to make Ctrl-C raise SIGINT on posix. The old behavior for Ctrl-C,

examples/async-execute.janet

@@ -0,0 +1,22 @@
+(defn dowork [name n]
+  (print name " starting work...")
+  (os/execute [(dyn :executable) "-e" (string "(os/sleep " n ")")])
+  (print name " finished work!"))
+
+# Will be done in parallel
+(print "starting group A")
+(ev/call dowork "A 2" 2)
+(ev/call dowork "A 1" 1)
+(ev/call dowork "A 3" 3)
+
+(ev/sleep 4)
+
+# Will also be done in parallel
+(print "starting group B")
+(ev/call dowork "B 2" 2)
+(ev/call dowork "B 1" 1)
+(ev/call dowork "B 3" 3)
+
+(ev/sleep 4)
+
+(print "all work done")

src/core/ev.c

@@ -31,12 +31,12 @@
 
 #ifdef JANET_EV
 
-/* Includes */
 #include <math.h>
 #ifdef JANET_WINDOWS
 #include <winsock2.h>
 #include <windows.h>
 #else
+#include <pthread.h>
 #include <limits.h>
 #include <errno.h>
 #include <unistd.h>
@@ -48,6 +48,7 @@
 #include <netinet/tcp.h>
 #include <netdb.h>
 #include <sys/socket.h>
+#include <sys/wait.h>
 #ifdef JANET_EV_EPOLL
 #include <sys/epoll.h>
 #include <sys/timerfd.h>
@@ -148,6 +149,7 @@ JANET_THREAD_LOCAL JanetRNG janet_vm_ev_rng;
 JANET_THREAD_LOCAL JanetListenerState **janet_vm_listeners = NULL;
 JANET_THREAD_LOCAL size_t janet_vm_listener_count = 0;
 JANET_THREAD_LOCAL size_t janet_vm_listener_cap = 0;
+JANET_THREAD_LOCAL size_t janet_vm_extra_listeners = 0;
 
 /* Get current timestamp (millisecond precision) */
 static JanetTimestamp ts_now(void);
@@ -519,6 +521,7 @@ void janet_ev_init_common(void) {
 /* Common deinit code */
 void janet_ev_deinit_common(void) {
     janet_q_deinit(&janet_vm_spawn);
+    free(janet_vm_tq);
     free(janet_vm_listeners);
     janet_vm_listeners = NULL;
 }
@@ -540,6 +543,14 @@ void janet_addtimeout(double sec) {
     add_timeout(to);
 }
 
+void janet_ev_inc_refcount(void) {
+    janet_vm_extra_listeners++;
+}
+
+void janet_ev_dec_refcount(void) {
+    janet_vm_extra_listeners--;
+}
+
 /* Channels */
 
 typedef struct {
@@ -839,14 +850,16 @@ void janet_loop1(void) {
             }
         }
     }
+
     /* Run scheduled fibers */
     while (janet_vm_spawn.head != janet_vm_spawn.tail) {
         JanetTask task = {NULL, janet_wrap_nil(), JANET_SIGNAL_OK};
         janet_q_pop(&janet_vm_spawn, &task, sizeof(task));
         run_one(task.fiber, task.value, task.sig);
     }
+
     /* Poll for events */
-    if (janet_vm_listener_count || janet_vm_tq_count) {
+    if (janet_vm_listener_count || janet_vm_tq_count || janet_vm_extra_listeners) {
         JanetTimeout to;
         memset(&to, 0, sizeof(to));
         int has_timeout;
@@ -855,18 +868,69 @@ void janet_loop1(void) {
             pop_timeout(0);
         }
         /* Run polling implementation only if pending timeouts or pending events */
-        if (janet_vm_tq_count || janet_vm_listener_count) {
+        if (janet_vm_tq_count || janet_vm_listener_count || janet_vm_extra_listeners) {
             janet_loop1_impl(has_timeout, to.when);
         }
     }
 }
 
 void janet_loop(void) {
-    while (janet_vm_listener_count || (janet_vm_spawn.head != janet_vm_spawn.tail) || janet_vm_tq_count) {
+    while (janet_vm_listener_count || (janet_vm_spawn.head != janet_vm_spawn.tail) || janet_vm_tq_count || janet_vm_extra_listeners) {
         janet_loop1();
     }
 }
 
+/*
+ * Self-pipe handling code.
+ */
+
+/* Wrap return value by pairing it with the callback used to handle it
+ * in the main thread */
+typedef struct {
+    JanetEVGenericMessage msg;
+    JanetThreadedCallback cb;
+} JanetSelfPipeEvent;
+
+/* Structure used to initialize threads in the thread pool
+ * (same head structure as self pipe event)*/
+typedef struct {
+    JanetEVGenericMessage msg;
+    JanetThreadedCallback cb;
+    JanetThreadedSubroutine subr;
+    JanetHandle write_pipe;
+} JanetEVThreadInit;
+
+#ifdef JANET_WINDOWS
+
+/* On windows, use PostQueuedCompletionStatus instead for
+ * custom events */
+
+#else
+
+static JANET_THREAD_LOCAL JanetHandle janet_vm_selfpipe[2];
+
+static void janet_ev_setup_selfpipe(void) {
+    if (janet_make_pipe(janet_vm_selfpipe)) {
+        JANET_EXIT("failed to initialize self pipe in event loop");
+    }
+}
+
+/* Handle events from the self pipe inside the event loop */
+static void janet_ev_handle_selfpipe(void) {
+    JanetSelfPipeEvent response;
+    while (read(janet_vm_selfpipe[0], &response, sizeof(response)) > 0) {
+        response.cb(response.msg);
+        janet_ev_dec_refcount();
+    }
+}
+
+static void janet_ev_cleanup_selfpipe(void) {
+    close(janet_vm_selfpipe[0]);
+    close(janet_vm_selfpipe[1]);
+}
+
+#endif
+
 #ifdef JANET_WINDOWS
 
 JANET_THREAD_LOCAL HANDLE janet_vm_iocp = NULL;
@@ -926,6 +990,12 @@ void janet_loop1_impl(int has_timeout, JanetTimestamp to) {
         if (!has_timeout) {
             /* queue emptied */
         }
+    } else if (0 == completionKey) {
+        /* Custom event */
+        JanetSelfPipeEvent *response = (JanetSelfPipeEvent *)(overlapped);
+        response->cb(response->msg);
+        free(response);
+        janet_ev_dec_refcount();
     } else {
         /* Normal event */
         JanetStream *stream = (JanetStream *) completionKey;
@@ -1034,8 +1104,14 @@ void janet_loop1_impl(int has_timeout, JanetTimestamp timeout) {
 
     /* Step state machines */
     for (int i = 0; i < ready; i++) {
-        JanetStream *stream = events[i].data.ptr;
-        if (NULL != stream) { /* If NULL, is a timeout */
+        void *p = events[i].data.ptr;
+        if (&janet_vm_timerfd == p) {
+            /* Timer expired, ignore */;
+        } else if (janet_vm_selfpipe == p) {
+            /* Self-pipe handling */
+            janet_ev_handle_selfpipe();
+        } else {
+            JanetStream *stream = p;
             int mask = events[i].events;
             JanetListenerState *state = stream->state;
             state->event = events + i;
@@ -1066,14 +1142,18 @@ void janet_loop1_impl(int has_timeout, JanetTimestamp timeout) {
 
 void janet_ev_init(void) {
     janet_ev_init_common();
+    janet_ev_setup_selfpipe();
     janet_vm_epoll = epoll_create1(EPOLL_CLOEXEC);
     janet_vm_timerfd = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC | TFD_NONBLOCK);
     janet_vm_timer_enabled = 0;
     if (janet_vm_epoll == -1 || janet_vm_timerfd == -1) goto error;
     struct epoll_event ev;
     ev.events = EPOLLIN | EPOLLET;
-    ev.data.ptr = NULL;
+    ev.data.ptr = &janet_vm_timerfd;
     if (-1 == epoll_ctl(janet_vm_epoll, EPOLL_CTL_ADD, janet_vm_timerfd, &ev)) goto error;
+    ev.events = EPOLLIN | EPOLLET;
+    ev.data.ptr = janet_vm_selfpipe;
+    if (-1 == epoll_ctl(janet_vm_epoll, EPOLL_CTL_ADD, janet_vm_selfpipe[0], &ev)) goto error;
     return;
 error:
     JANET_EXIT("failed to initialize event loop");
@@ -1083,6 +1163,7 @@ void janet_ev_deinit(void) {
     janet_ev_deinit_common();
     close(janet_vm_epoll);
     close(janet_vm_timerfd);
+    janet_ev_cleanup_selfpipe();
     janet_vm_epoll = 0;
 }
 
@@ -1119,7 +1200,7 @@ JanetListenerState *janet_listen(JanetStream *stream, JanetListener behavior, in
     JanetListenerState *state = janet_listen_impl(stream, behavior, mask, size, user);
     size_t newsize = janet_vm_listener_cap;
     if (newsize > oldsize) {
-        janet_vm_fds = realloc(janet_vm_fds, newsize * sizeof(struct pollfd));
+        janet_vm_fds = realloc(janet_vm_fds, (newsize + 1) * sizeof(struct pollfd));
         if (NULL == janet_vm_fds) {
             JANET_OUT_OF_MEMORY;
         }
@@ -1128,12 +1209,12 @@ JanetListenerState *janet_listen(JanetStream *stream, JanetListener behavior, in
     ev.fd = stream->handle;
     ev.events = make_poll_events(state->stream->_mask);
     ev.revents = 0;
-    janet_vm_fds[state->_index] = ev;
+    janet_vm_fds[state->_index + 1] = ev;
     return state;
 }
 
 static void janet_unlisten(JanetListenerState *state) {
-    janet_vm_fds[state->_index] = janet_vm_fds[janet_vm_listener_count - 1];
+    janet_vm_fds[state->_index + 1] = janet_vm_fds[janet_vm_listener_count];
     janet_unlisten_impl(state);
 }
 
@@ -1146,19 +1227,25 @@ void janet_loop1_impl(int has_timeout, JanetTimestamp timeout) {
             JanetTimestamp now = ts_now();
             to = now > timeout ? 0 : (int)(timeout - now);
         }
-        ready = poll(janet_vm_fds, janet_vm_listener_count, to);
+        ready = poll(janet_vm_fds, janet_vm_listener_count + 1, to);
     } while (ready == -1 && errno == EINTR);
     if (ready == -1) {
         JANET_EXIT("failed to poll events");
     }
 
+    /* Check selfpipe */
+    if (janet_vm_fds[0].revents & POLLIN) {
+        janet_vm_fds[0].revents = 0;
+        janet_ev_handle_selfpipe();
+    }
+
     /* Step state machines */
     for (size_t i = 0; i < janet_vm_listener_count; i++) {
-        struct pollfd *pfd = janet_vm_fds + i;
+        struct pollfd *pfd = janet_vm_fds + i + 1;
         /* Skip fds where nothing interesting happened */
         JanetListenerState *state = janet_vm_listeners[i];
         /* Normal event */
-        int mask = janet_vm_fds[i].revents;
+        int mask = pfd->revents;
         JanetAsyncStatus status1 = JANET_ASYNC_STATUS_NOT_DONE;
         JanetAsyncStatus status2 = JANET_ASYNC_STATUS_NOT_DONE;
         JanetAsyncStatus status3 = JANET_ASYNC_STATUS_NOT_DONE;
@@ -1183,20 +1270,157 @@ void janet_loop1_impl(int has_timeout, JanetTimestamp timeout) {
 void janet_ev_init(void) {
     janet_ev_init_common();
     janet_vm_fds = NULL;
+    janet_ev_setup_selfpipe();
+    janet_vm_fds = malloc(sizeof(struct pollfd));
+    if (NULL == janet_vm_fds) {
+        JANET_OUT_OF_MEMORY;
+    }
+    janet_vm_fds[0].fd = janet_vm_selfpipe[0];
+    janet_vm_fds[0].events = POLLIN;
+    janet_vm_fds[0].revents = 0;
     return;
 }
 
 void janet_ev_deinit(void) {
     janet_ev_deinit_common();
+    janet_ev_cleanup_selfpipe();
     free(janet_vm_fds);
     janet_vm_fds = NULL;
 }
 
 #endif
 
-/* C API helpers for reading and writing from streams.
+/*
+ * End poll implementation
+ */
+
+/*
+ * Threaded calls
+ */
+
+#ifdef JANET_WINDOWS
+static DWORD WINAPI janet_thread_body(LPVOID ptr) {
+    JanetEVThreadInit *init = (JanetEVThreadInit *)ptr;
+    JanetEVGenericMessage msg = init->msg;
+    JanetThreadedSubroutine subr = init->subr;
+    JanetThreadedCallback cb = init->cb;
+    JanetHandle iocp = init->write_pipe;
+    /* Reuse memory from thread init for returning data */
+    init->msg = subr(msg);
+    init->cb = cb;
+    janet_assert(PostQueuedCompletionStatus(iocp,
+                                            sizeof(JanetSelfPipeEvent),
+                                            0,
+                                            (LPOVERLAPPED) init),
+                 "failed to post completion event");
+    return 0;
+}
+#else
+static void *janet_thread_body(void *ptr) {
+    JanetEVThreadInit *init = (JanetEVThreadInit *)ptr;
+    JanetEVGenericMessage msg = init->msg;
+    JanetThreadedSubroutine subr = init->subr;
+    JanetThreadedCallback cb = init->cb;
+    int fd = init->write_pipe;
+    free(init);
+    JanetSelfPipeEvent response;
+    response.msg = subr(msg);
+    response.cb = cb;
+    /* handle a bit of back pressure before giving up. */
+    int tries = 4;
+    while (tries > 0) {
+        int status;
+        do {
+            status = write(fd, &response, sizeof(response));
+        } while (status == -1 && errno == EINTR);
+        if (status > 0) break;
+        sleep(1);
+        tries--;
+    }
+    return NULL;
+}
+#endif
+
+void janet_ev_threaded_call(JanetThreadedSubroutine fp, JanetEVGenericMessage arguments, JanetThreadedCallback cb) {
+    JanetEVThreadInit *init = malloc(sizeof(JanetEVThreadInit));
+    if (NULL == init) {
+        JANET_OUT_OF_MEMORY;
+    }
+    init->msg = arguments;
+    init->subr = fp;
+    init->cb = cb;
+
+#ifdef JANET_WINDOWS
+    init->write_pipe = janet_vm_iocp;
+    HANDLE thread_handle = CreateThread(NULL, 0, janet_thread_body, init, 0, NULL);
+    if (NULL == thread_handle) {
+        free(init);
+        janet_panic("failed to create thread");
+    }
+    CloseHandle(thread_handle); /* detach from thread */
+#else
+    init->write_pipe = janet_vm_selfpipe[1];
+    pthread_t waiter_thread;
+    int err = pthread_create(&waiter_thread, NULL, janet_thread_body, init);
+    if (err) {
+        free(init);
+        janet_panicf("%s", strerror(err));
+    }
+    pthread_detach(waiter_thread);
+#endif
+
+    /* Increment ev refcount so we don't quit while waiting for a subprocess */
+    janet_ev_inc_refcount();
+}
+
+/* Default callback for janet_ev_threaded_await. */
+void janet_ev_default_threaded_callback(JanetEVGenericMessage return_value) {
+    switch (return_value.tag) {
+        default:
+        case JANET_EV_TCTAG_NIL:
+            janet_schedule(return_value.fiber, janet_wrap_nil());
+            break;
+        case JANET_EV_TCTAG_INTEGER:
+            janet_schedule(return_value.fiber, janet_wrap_integer(return_value.argi));
+            break;
+        case JANET_EV_TCTAG_STRING:
+        case JANET_EV_TCTAG_STRINGF:
+            janet_schedule(return_value.fiber, janet_cstringv((const char *) return_value.argp));
+            if (return_value.tag == JANET_EV_TCTAG_STRINGF) free(return_value.argp);
+            break;
+        case JANET_EV_TCTAG_KEYWORD:
+            janet_schedule(return_value.fiber, janet_ckeywordv((const char *) return_value.argp));
+            break;
+        case JANET_EV_TCTAG_ERR_STRING:
+        case JANET_EV_TCTAG_ERR_STRINGF:
+            janet_cancel(return_value.fiber, janet_cstringv((const char *) return_value.argp));
+            if (return_value.tag == JANET_EV_TCTAG_STRINGF) free(return_value.argp);
+            break;
+        case JANET_EV_TCTAG_ERR_KEYWORD:
+            janet_cancel(return_value.fiber, janet_ckeywordv((const char *) return_value.argp));
+            break;
+    }
+    janet_gcunroot(janet_wrap_fiber(return_value.fiber));
+}
+
+
+/* Convenience method for common case */
+void janet_ev_threaded_await(JanetThreadedSubroutine fp, int tag, int argi, void *argp) {
+    JanetEVGenericMessage arguments;
+    arguments.tag = tag;
+    arguments.argi = argi;
+    arguments.argp = argp;
+    arguments.fiber = janet_root_fiber();
+    janet_gcroot(janet_wrap_fiber(arguments.fiber));
+    janet_ev_threaded_call(fp, arguments, janet_ev_default_threaded_callback);
+    janet_await();
+}
+
+/*
+ * C API helpers for reading and writing from streams.
  * There is some networking code in here as well as generic
- * reading and writing primitives. */
+ * reading and writing primitives.
+ */
 
 void janet_stream_flags(JanetStream *stream, uint32_t flags) {
     if (stream->flags & JANET_STREAM_CLOSED) {
@@ -1730,7 +1954,13 @@ int janet_make_pipe(JanetHandle handles[2]) {
     return 0;
 #else
     if (pipe(handles)) return -1;
+    if (fcntl(handles[0], F_SETFL, O_NONBLOCK)) goto error;
+    if (fcntl(handles[1], F_SETFL, O_NONBLOCK)) goto error;
     return 0;
+error:
+    close(handles[0]);
+    close(handles[1]);
+    return -1;
 #endif
 }
 
@@ -1755,9 +1985,7 @@ static Janet cfun_ev_call(int32_t argc, Janet *argv) {
     return janet_wrap_fiber(fiber);
 }
 
-static Janet cfun_ev_sleep(int32_t argc, Janet *argv) {
-    janet_fixarity(argc, 1);
-    double sec = janet_getnumber(argv, 0);
+JANET_NO_RETURN void janet_sleep_await(double sec) {
     JanetTimeout to;
     to.when = ts_delta(ts_now(), sec);
     to.fiber = janet_vm_root_fiber;
@@ -1768,6 +1996,12 @@ static Janet cfun_ev_sleep(int32_t argc, Janet *argv) {
     janet_await();
 }
 
+static Janet cfun_ev_sleep(int32_t argc, Janet *argv) {
+    janet_fixarity(argc, 1);
+    double sec = janet_getnumber(argv, 0);
+    janet_sleep_await(sec);
+}
+
 static Janet cfun_ev_deadline(int32_t argc, Janet *argv) {
     janet_arity(argc, 1, 3);
     double sec = janet_getnumber(argv, 0);

src/core/io.c

@@ -777,7 +777,7 @@ static const JanetReg io_cfuns[] = {
 #ifndef JANET_NO_PROCESSES
     {
         "file/popen", cfun_io_popen,
-        JDOC("(file/popen command &opt mode)\n\n"
+        JDOC("(file/popen command &opt mode) (DEPRECATED for os/spawn)\n\n"
              "Open a file that is backed by a process. The file must be opened in either "
              "the :r (read) or the :w (write) mode. In :r mode, the stdout of the "
              "process can be read from the file. In :w mode, the stdin of the process "

src/core/os.c

@@ -1,5 +1,5 @@
 /*
-* Copyright (c) 2020 Calvin Rose
+* Copyright (c) 2021 Calvin Rose
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
@@ -185,6 +185,7 @@ static Janet os_exit(int32_t argc, Janet *argv) {
 #ifndef JANET_REDUCED_OS
 
 #ifndef JANET_NO_PROCESSES
+
 /* Get env for os_execute */
 static char **os_execute_env(int32_t argc, const Janet *argv) {
     char **envp = NULL;
@@ -319,13 +320,15 @@ static JanetBuffer *os_exec_escape(JanetView args) {
 static const JanetAbstractType ProcAT;
 #define JANET_PROC_CLOSED 1
 #define JANET_PROC_WAITED 2
+#define JANET_PROC_WAITING 4
+#define JANET_PROC_ERROR_NONZERO 8
 typedef struct {
     int flags;
 #ifdef JANET_WINDOWS
     HANDLE pHandle;
     HANDLE tHandle;
 #else
-    int pid;
+    pid_t pid;
 #endif
     int return_code;
 #ifdef JANET_EV
@@ -339,6 +342,62 @@ typedef struct {
 #endif
 } JanetProc;
 
+#ifdef JANET_EV
+
+#ifdef JANET_WINDOWS
+
+static JanetEVGenericMessage janet_proc_wait_subr(JanetEVGenericMessage args) {
+    JanetProc *proc = (JanetProc *) args.argp;
+    WaitForSingleObject(proc->pHandle, INFINITE);
+    GetExitCodeProcess(proc->pHandle, &args.argi);
+    return args;
+}
+
+#else /* windows check */
+
+/* Function that is called in separate thread to wait on a pid */
+static JanetEVGenericMessage janet_proc_wait_subr(JanetEVGenericMessage args) {
+    JanetProc *proc = (JanetProc *) args.argp;
+    pid_t result;
+    int status = 0;
+    do {
+        result = waitpid(proc->pid, &status, 0);
+    } while (result == -1 && errno == EINTR);
+    /* Use POSIX shell semantics for interpreting signals */
+    if (WIFEXITED(status)) {
+        status = WEXITSTATUS(status);
+    } else if (WIFSTOPPED(status)) {
+        status = WSTOPSIG(status) + 128;
+    } else {
+        status = WTERMSIG(status) + 128;
+    }
+    args.argi = status;
+    return args;
+}
+
+#endif /* End windows check */
+
+/* Callback that is called in main thread when subroutine completes. */
+static void janet_proc_wait_cb(JanetEVGenericMessage args) {
+    int status = args.argi;
+    JanetProc *proc = (JanetProc *) args.argp;
+    if (NULL != proc) {
+        proc->return_code = (int32_t) status;
+        proc->flags |= JANET_PROC_WAITED;
+        proc->flags &= ~JANET_PROC_WAITING;
+        janet_gcunroot(janet_wrap_abstract(proc));
+        janet_gcunroot(janet_wrap_fiber(args.fiber));
+        if ((status != 0) && (proc->flags & JANET_PROC_ERROR_NONZERO)) {
+            JanetString s = janet_formatc("command failed with non-zero exit code %d", status);
+            janet_cancel(args.fiber, janet_wrap_string(s));
+        } else {
+            janet_schedule(args.fiber, janet_wrap_integer(status));
+        }
+    }
+}
+
+#endif /* End ev check */
+
 static int janet_proc_gc(void *p, size_t s) {
     (void) s;
     JanetProc *proc = (JanetProc *) p;
@@ -367,10 +426,28 @@ static int janet_proc_mark(void *p, size_t s) {
     return 0;
 }
 
-static Janet os_proc_wait_impl(JanetProc *proc) {
-    if (proc->flags & JANET_PROC_WAITED) {
-        janet_panicf("cannot wait on process that has already finished");
+#ifdef JANET_EV
+static JANET_NO_RETURN void
+#else
+static Janet
+#endif
+os_proc_wait_impl(JanetProc *proc) {
+    if (proc->flags & (JANET_PROC_WAITED | JANET_PROC_WAITING)) {
+        janet_panicf("cannot wait twice on a process");
     }
+#ifdef JANET_EV
+    /* Event loop implementation - threaded call */
+    proc->flags |= JANET_PROC_WAITING;
+    JanetEVGenericMessage targs;
+    memset(&targs, 0, sizeof(targs));
+    targs.argp = proc;
+    targs.fiber = janet_root_fiber();
+    janet_gcroot(janet_wrap_abstract(proc));
+    janet_gcroot(janet_wrap_fiber(targs.fiber));
+    janet_ev_threaded_call(janet_proc_wait_subr, targs, janet_proc_wait_cb);
+    janet_await();
+#else
+    /* Non evented implementation */
     proc->flags |= JANET_PROC_WAITED;
     int status = 0;
 #ifdef JANET_WINDOWS
@@ -386,6 +463,7 @@ static Janet os_proc_wait_impl(JanetProc *proc) {
 #endif
     proc->return_code = (int32_t) status;
     return janet_wrap_integer(proc->return_code);
+#endif
 }
 
 static Janet os_proc_wait(int32_t argc, Janet *argv) {
@@ -481,7 +559,7 @@ static int janet_proc_get(void *p, Janet key, Janet *out) {
         return 1;
     }
     if (janet_keyeq(key, "err")) {
-        *out = (NULL == proc->out) ? janet_wrap_nil() : janet_wrap_abstract(proc->err);
+        *out = (NULL == proc->err) ? janet_wrap_nil() : janet_wrap_abstract(proc->err);
         return 1;
     }
     if ((-1 != proc->return_code) && janet_keyeq(key, "return-code")) {
@@ -575,7 +653,7 @@ static JanetFile *get_stdio_for_handle(JanetHandle handle, void *orig, int iswri
 }
 #endif
 
-static Janet os_execute_impl(int32_t argc, Janet *argv, int is_async) {
+static Janet os_execute_impl(int32_t argc, Janet *argv, int is_spawn) {
     janet_arity(argc, 1, 3);
 
     /* Get flags */
@@ -713,7 +791,7 @@ static Janet os_execute_impl(int32_t argc, Janet *argv, int is_async) {
     tHandle = processInfo.hThread;
 
     /* Wait and cleanup immedaitely */
-    if (!is_async) {
+    if (!is_spawn) {
         DWORD code;
         WaitForSingleObject(pHandle, INFINITE);
         GetExitCodeProcess(pHandle, &code);
@@ -781,25 +859,15 @@ static Janet os_execute_impl(int32_t argc, Janet *argv, int is_async) {
     if (status) {
         os_execute_cleanup(envp, child_argv);
         janet_panicf("%p: %s", argv[0], strerror(errno));
-    } else if (is_async) {
+    } else if (is_spawn) {
         /* Get process handle */
         os_execute_cleanup(envp, child_argv);
     } else {
         /* Wait to complete */
-        waitpid(pid, &status, 0);
         os_execute_cleanup(envp, child_argv);
-        /* Use POSIX shell semantics for interpreting signals */
-        if (WIFEXITED(status)) {
-            status = WEXITSTATUS(status);
-        } else if (WIFSTOPPED(status)) {
-            status = WSTOPSIG(status) + 128;
-        } else {
-            status = WTERMSIG(status) + 128;
-        }
     }
 
 #endif
-    if (is_async) {
     JanetProc *proc = janet_abstract(&ProcAT, sizeof(JanetProc));
     proc->return_code = -1;
 #ifdef JANET_WINDOWS
@@ -808,18 +876,34 @@ static Janet os_execute_impl(int32_t argc, Janet *argv, int is_async) {
 #else
     proc->pid = pid;
 #endif
-        proc->in = get_stdio_for_handle(new_in, orig_in, 1);
-        proc->out = get_stdio_for_handle(new_out, orig_out, 0);
-        proc->err = get_stdio_for_handle(new_err, orig_err, 0);
-        proc->flags = 0;
-        if (proc->in == NULL || proc->out == NULL || proc->err == NULL) {
-            janet_panic("failed to construct proc");
+    proc->in = NULL;
+    proc->out = NULL;
+    proc->err = NULL;
+    if (new_in != JANET_HANDLE_NONE) {
+        proc->in = get_stdio_for_handle(new_in, orig_in, 0);
+        if (NULL == proc->in) janet_panic("failed to construct proc");
     }
+    if (new_out != JANET_HANDLE_NONE) {
+        proc->out = get_stdio_for_handle(new_out, orig_out, 1);
+        if (NULL == proc->out) janet_panic("failed to construct proc");
+    }
+    if (new_err != JANET_HANDLE_NONE) {
+        proc->err = get_stdio_for_handle(new_err, orig_err, 1);
+        if (NULL == proc->err) janet_panic("failed to construct proc");
+    }
+    proc->flags = 0;
+    if (janet_flag_at(flags, 2)) {
+        proc->flags |= JANET_PROC_ERROR_NONZERO;
+    }
+
+    if (is_spawn) {
         return janet_wrap_abstract(proc);
-    } else if (janet_flag_at(flags, 2) && status) {
-        janet_panicf("command failed with non-zero exit code %d", status);
     } else {
-        return janet_wrap_integer(status);
+#ifdef JANET_EV
+        os_proc_wait_impl(proc);
+#else
+        return os_proc_wait_impl(proc);
+#endif
     }
 }
 
@@ -2078,6 +2162,8 @@ void janet_lib_os(JanetTable *env) {
         InitializeCriticalSection(&env_lock);
         env_lock_initialized = 1;
     }
+#endif
+#ifndef JANET_NO_PROCESSES
 #endif
     janet_core_cfuns(env, NULL, os_cfuns);
 }

src/core/vm.c

@@ -1478,7 +1478,6 @@ int janet_init(void) {
     janet_vm_fiber = NULL;
     janet_vm_root_fiber = NULL;
     janet_vm_stackn = 0;
-    /* Threads */
 #ifdef JANET_THREADS
     janet_threads_init();
 #endif

src/include/janet.h

@@ -1279,14 +1279,59 @@ JANET_API JanetListenerState *janet_listen(JanetStream *stream, JanetListener be
 
 /* Shorthand for yielding to event loop in C */
 JANET_NO_RETURN JANET_API void janet_await(void);
+JANET_NO_RETURN JANET_API void janet_sleep_await(double sec);
 
 /* For use inside listeners - adds a timeout to the current fiber, such that
  * it will be resumed after sec seconds if no other event schedules the current fiber. */
 JANET_API void janet_addtimeout(double sec);
+JANET_API void janet_ev_inc_refcount(void);
+JANET_API void janet_ev_dec_refcount(void);
 
 /* Get last error from a an IO operation */
 JANET_API Janet janet_ev_lasterr(void);
 
+/* Async service for calling a function or syscall in a background thread. This is not
+ * as efficient in the slightest as using Streams but can be used for arbitrary blocking
+ * functions and syscalls. */
+
+/* Used to pass data between the main thread and worker threads for simple tasks.
+ * We could just use a pointer but this prevents malloc/free in the common case
+ * of only a handful of arguments. */
+typedef struct {
+    int tag;
+    int argi;
+    void *argp;
+    JanetFiber *fiber;
+} JanetEVGenericMessage;
+
+/* How to resume or cancel after a threaded call. Not exhaustive of the possible
+ * ways one might want to resume after returning from a threaded call, but should
+ * cover most of the common cases. For something more complicated, such as resuming
+ * with an abstract type or a struct, one should use janet_ev_threaded_call instead
+ * of janet_ev_threaded_await with a custom callback. */
+
+#define JANET_EV_TCTAG_NIL 0          /* resume with nil */
+#define JANET_EV_TCTAG_INTEGER 1      /* resume with janet_wrap_integer(argi) */
+#define JANET_EV_TCTAG_STRING 2       /* resume with janet_cstringv((const char *) argp) */
+#define JANET_EV_TCTAG_STRINGF 3      /* resume with janet_cstringv((const char *) argp), then call free on argp. */
+#define JANET_EV_TCTAG_KEYWORD 4      /* resume with janet_ckeywordv((const char *) argp) */
+#define JANET_EV_TCTAG_ERR_STRING 5   /* cancel with janet_cstringv((const char *) argp) */
+#define JANET_EV_TCTAG_ERR_STRINGF 6  /* cancel with janet_cstringv((const char *) argp), then call free on argp. */
+#define JANET_EV_TCTAG_ERR_KEYWORD 7  /* cancel with janet_ckeywordv((const char *) argp) */
+
+/* Function pointer that is run in the thread pool */
+typedef JanetEVGenericMessage(*JanetThreadedSubroutine)(JanetEVGenericMessage arguments);
+
+/* Handler that is run in the main thread with the result of the JanetAsyncSubroutine */
+typedef void (*JanetThreadedCallback)(JanetEVGenericMessage return_value);
+
+/* API calls for quickly offloading some work in C to a new thread or thread pool. */
+JANET_API void janet_ev_threaded_call(JanetThreadedSubroutine fp, JanetEVGenericMessage arguments, JanetThreadedCallback cb);
+JANET_API void janet_ev_threaded_await(JanetThreadedSubroutine fp, int tag, int argi, void *argp);
+
+/* Callback used by janet_ev_threaded_await */
+JANET_API void janet_ev_default_threaded_callback(JanetEVGenericMessage return_value);
+
 /* Read async from a stream */
 JANET_API void janet_ev_read(JanetStream *stream, JanetBuffer *buf, int32_t nbytes);
 JANET_API void janet_ev_readchunk(JanetStream *stream, JanetBuffer *buf, int32_t nbytes);

test/suite0009.janet

@@ -40,7 +40,7 @@
 # or else the first read can fail. Might be a strange windows
 # "bug", but needs further investigating. Otherwise, `build_win test`
 # can sometimes fail on windows, leading to flaky testing.
-(ev/sleep 0.2)
+(ev/sleep 0.3)
 
 (defn test-echo [msg]
   (with [conn (net/connect "127.0.0.1" "8000")]
@@ -59,6 +59,7 @@
 (var pipe-counter 0)
 (def chan (ev/chan 10))
 (let [[reader writer] (os/pipe)]
+  (ev/sleep 0.3)
   (ev/spawn
     (while (ev/read reader 3)
       (++ pipe-counter))