std: get_monitor_task_gl() is global_loop::get() default

src/libstd/uv_global_loop.rs

@@ -1,15 +1,16 @@
 #[doc="
-Process-wide, lazily started/stopped libuv event loop interaction.
+A process-wide libuv event loop for library use.
 "];
 
 import ll = uv_ll;
 import hl = uv_hl;
 import get_gl = get;
 
-export get, get_single_task_gl;
+export get, get_single_task_gl, get_monitor_task_gl;
 
 native mod rustrt {
     fn rust_uv_get_kernel_global_chan_ptr() -> *libc::uintptr_t;
+    fn rust_uv_get_kernel_monitor_global_chan_ptr() -> *libc::uintptr_t;
     fn rust_uv_get_kernel_global_async_handle() -> *libc::uintptr_t;
     fn rust_compare_and_swap_ptr(address: *libc::uintptr_t,
                                  oldval: libc::uintptr_t,
@@ -20,13 +21,34 @@ native mod rustrt {
 Race-free helper to get access to a global task where a libuv
 loop is running.
 
+Use `uv::hl::interact`, `uv::hl::ref_handle` and `uv::hl::unref_handle` to
+do operations against the global loop that this function returns.
+
 # Return
 
 * A `hl::high_level_loop` that encapsulates communication with the global
 loop.
 "]
 fn get() -> hl::high_level_loop {
-    ret get_single_task_gl();
+    ret get_monitor_task_gl();
+}
+
+#[doc(hidden)]
+fn get_monitor_task_gl() -> hl::high_level_loop {
+    let monitor_loop_chan =
+        rustrt::rust_uv_get_kernel_monitor_global_chan_ptr();
+    ret spawn_global_weak_task(
+        monitor_loop_chan,
+        {|weak_exit_po, msg_po, loop_ptr, first_msg|
+            log(debug, "monitor gl: entering inner loop");
+            unsafe {
+                monitor_task_loop_body(weak_exit_po, msg_po, loop_ptr,
+                                       copy(first_msg))
+            }
+        },
+        {|msg_ch|
+            hl::monitor_task_loop({op_chan: msg_ch})
+        });
 }
 
 #[doc(hidden)]
@@ -35,7 +57,7 @@ fn get_single_task_gl() -> hl::high_level_loop {
     ret spawn_global_weak_task(
         global_loop_chan_ptr,
         {|weak_exit_po, msg_po, loop_ptr, first_msg|
-            log(debug, "about to enter inner loop");
+            log(debug, "single-task gl: about to enter inner loop");
             unsafe {
                 single_task_loop_body(weak_exit_po, msg_po, loop_ptr,
                                       copy(first_msg))
@@ -135,6 +157,83 @@ unsafe fn outer_global_loop_body(
 
     ll::loop_delete(loop_ptr);
 }
+
+unsafe fn monitor_task_loop_body(weak_exit_po_in: comm::port<()>,
+                          msg_po_in: comm::port<hl::high_level_msg>,
+                          loop_ptr: *libc::c_void,
+                          -first_interaction: hl::high_level_msg) -> bool {
+    // resend the msg to be handled in the select2 loop below..
+    comm::send(comm::chan(msg_po_in), first_interaction);
+
+    // our async_handle
+    let async_handle_po = comm::port::<*ll::uv_async_t>();
+    let async_handle_ch = comm::chan(async_handle_po);
+
+    // the msg_po that libuv will be receiving on..
+    let loop_msg_po = comm::port::<hl::high_level_msg>();
+    let loop_msg_po_ptr = ptr::addr_of(loop_msg_po);
+    let loop_msg_ch = comm::chan(loop_msg_po);
+
+    // the question of whether unsupervising this will even do any
+    // good is there.. but since this'll go into blocking in libuv with
+    // a quickness.. any errors that occur (including inside crust) will
+    // be segfaults.. so yeah.
+    task::spawn_sched(task::manual_threads(1u)) {||
+        let loop_msg_po_in = *loop_msg_po_ptr;
+        hl::run_high_level_loop(
+            loop_ptr,
+            loop_msg_po_in, // here the loop gets handed a different message
+                            // port, as we'll be receiving all of the messages
+                            // initially and then passing them on..
+            // before_run
+            {|async_handle|
+                log(debug,#fmt("monitor gl: before_run: async_handle %?",
+                              async_handle));
+                // when this is ran, our async_handle is set up, so let's
+                // do an async_send with it.. letting the loop know, once it
+                // starts, that is has work
+                ll::async_send(async_handle);
+                comm::send(async_handle_ch, copy(async_handle));
+            },
+            // before_msg_drain
+            {|async_handle|
+                log(debug,#fmt("monitor gl: b4_msg_drain: async_handle %?",
+                              async_handle));
+                true
+            },
+            // before_tear_down
+            {|async_handle|
+                log(debug,#fmt("monitor gl: b4_tear_down: async_handle %?",
+                              async_handle));
+            });
+    };
+
+    // our loop is set up, so let's emit the handle back out to our users..
+    let async_handle = comm::recv(async_handle_po);
+    // supposed to return a bool to indicate to the enclosing loop whether
+    // it should continue or not..
+    let mut continue_inner_loop = true;
+    let mut didnt_get_hl_bailout = true;
+    while continue_inner_loop {
+        log(debug, "monitor task inner loop.. about to block on select2");
+        continue_inner_loop = either::either(
+            {|left_val|
+                // bail out..
+                log(debug, #fmt("monitor inner weak_exit_po recv'd msg: %?",
+                               left_val));
+                // TODO: make loop bail out
+                didnt_get_hl_bailout = false;
+                false
+            }, {|right_val|
+                // wake up our inner loop and pass it a msg..
+                comm::send(loop_msg_ch, copy(right_val));
+                ll::async_send(async_handle);
+                true
+            }, comm::select2(weak_exit_po_in, msg_po_in)
+        )
+    }
+    didnt_get_hl_bailout
+}
 
 unsafe fn single_task_loop_body(weak_exit_po_in: comm::port<()>,
                           msg_po_in: comm::port<hl::high_level_msg>,

src/libstd/uv_hl.rs

@@ -193,12 +193,17 @@ unsafe fn send_high_level_msg(hl_loop: high_level_loop,
     // the loop isn't active, so we don't need to wake it up,
     // (the loop's enclosing task should be blocking on a message
     // receive on this port)
-    if (*(hl_loop.async_handle()) != 0 as *ll::uv_async_t) {
-        log(debug,"global async handle != 0, waking up loop..");
-        ll::async_send(*(hl_loop.async_handle()));
-    }
-    else {
-        log(debug,"GLOBAL ASYNC handle == 0");
+    alt hl_loop {
+      single_task_loop({async_handle, op_chan}) {
+        if ((*async_handle) != 0 as *ll::uv_async_t) {
+            log(debug,"global async handle != 0, waking up loop..");
+            ll::async_send((*async_handle));
+        }
+        else {
+            log(debug,"GLOBAL ASYNC handle == 0");
+        }
+      }
+      _ {}
     }
 }
 

src/rt/rust_uv.cpp

@@ -446,6 +446,11 @@ rust_uv_get_kernel_global_chan_ptr() {
     return result;
 }
 
+extern "C" uintptr_t*
+rust_uv_get_kernel_monitor_global_chan_ptr() {
+	return rust_uv_get_kernel_global_chan_ptr();
+}
+
 extern "C" uintptr_t*
 rust_uv_get_kernel_global_async_handle() {
     return rust_get_current_task()->kernel->get_global_async_handle();

src/rt/rustrt.def.in

@@ -138,6 +138,7 @@ rust_uv_set_data_for_req
 rust_uv_get_base_from_buf
 rust_uv_get_len_from_buf
 rust_uv_get_kernel_global_chan_ptr
+rust_uv_get_kernel_monitor_global_chan_ptr
 rust_uv_get_kernel_global_async_handle
 rust_dbg_lock_create
 rust_dbg_lock_destroy