std: refactor global_loop::get.. make it reusable

2 files changed, 88 insertions, 22 deletions

diff --git a/src/libstd/uv_global_loop.rs b/src/libstd/uv_global_loop.rs
index 74cb9e4442c..b220ba9fe19 100644
--- a/src/libstd/uv_global_loop.rs
+++ b/src/libstd/uv_global_loop.rs
@@ -6,7 +6,7 @@ import ll = uv_ll;
 import hl = uv_hl;
 import get_gl = get;
 
-export get;
+export get, get_single_task_gl;
 
 native mod rustrt {
     fn rust_uv_get_kernel_global_chan_ptr() -> *libc::uintptr_t;
@@ -26,7 +26,44 @@ loop is running.
 loop.
 "]
 fn get() -> hl::high_level_loop {
+    ret get_single_task_gl();
+}
+
+#[doc(hidden)]
+fn get_single_task_gl() -> hl::high_level_loop {
     let global_loop_chan_ptr = rustrt::rust_uv_get_kernel_global_chan_ptr();
+    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");
+            unsafe {
+                single_task_loop_body(weak_exit_po, msg_po, loop_ptr,
+                                      copy(first_msg))
+            }
+        },
+        {|msg_ch|
+            log(debug, "after priv::chan_from_global_ptr");
+            unsafe {
+                let handle = get_global_async_handle_native_representation()
+                    as **ll::uv_async_t;
+                hl::single_task_loop(
+                    { async_handle: handle, op_chan: msg_ch })
+            }
+        }
+    );
+}
+
+// INTERNAL API
+
+fn spawn_global_weak_task(
+        global_loop_chan_ptr: *libc::uintptr_t,
+        weak_task_body_cb: fn~(
+            comm::port<()>,
+            comm::port<hl::high_level_msg>,
+            *libc::c_void,
+            hl::high_level_msg) -> bool,
+        after_task_spawn_cb: fn~(comm::chan<hl::high_level_msg>)
+          -> hl::high_level_loop) -> hl::high_level_loop {
     log(debug, #fmt("ENTERING global_loop::get() loop chan: %?",
        global_loop_chan_ptr));
 
@@ -44,25 +81,26 @@ fn get() -> hl::high_level_loop {
     };
     unsafe {
         log(debug, "before priv::chan_from_global_ptr");
-        let chan = priv::chan_from_global_ptr::<hl::high_level_msg>(
+        let msg_ch = priv::chan_from_global_ptr::<hl::high_level_msg>(
             global_loop_chan_ptr,
             builder_fn) {|port|
 
             // the actual body of our global loop lives here
             log(debug, "initialized global port task!");
             log(debug, "GLOBAL initialized global port task!");
-            outer_global_loop_body(port);
+            outer_global_loop_body(port, weak_task_body_cb);
         };
-        log(debug, "after priv::chan_from_global_ptr");
-        let handle = get_global_async_handle_native_representation()
-            as **ll::uv_async_t;
-        ret { async_handle: handle, op_chan: chan };
+        ret after_task_spawn_cb(msg_ch);
     }
 }
 
-// INTERNAL API
-
-unsafe fn outer_global_loop_body(msg_po: comm::port<hl::high_level_msg>) {
+unsafe fn outer_global_loop_body(
+    msg_po: comm::port<hl::high_level_msg>,
+    weak_task_body_cb: fn~(
+        comm::port<()>,
+        comm::port<hl::high_level_msg>,
+        *libc::c_void,
+        hl::high_level_msg) -> bool) {
     // we're going to use a single libuv-generated loop ptr
     // for the duration of the process
     let loop_ptr = ll::loop_new();
@@ -87,9 +125,8 @@ unsafe fn outer_global_loop_body(msg_po: comm::port<hl::high_level_msg>) {
                                    left_val));
                     false
                 }, {|right_val|
-                    log(debug, "about to enter inner loop");
-                    inner_global_loop_body(weak_exit_po, msg_po, loop_ptr,
-                                          copy(right_val))
+                    weak_task_body_cb(weak_exit_po, msg_po, loop_ptr,
+                                      right_val)
                 }, comm::select2(weak_exit_po, msg_po));
             log(debug,#fmt("GLOBAL LOOP EXITED, WAITING TO RESTART? %?",
                        continue));
@@ -99,7 +136,7 @@ unsafe fn outer_global_loop_body(msg_po: comm::port<hl::high_level_msg>) {
     ll::loop_delete(loop_ptr);
 }
 
-unsafe fn inner_global_loop_body(weak_exit_po_in: comm::port<()>,
+unsafe fn single_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 {
diff --git a/src/libstd/uv_hl.rs b/src/libstd/uv_hl.rs
index 5cc58932c4b..b235cdd5e07 100644
--- a/src/libstd/uv_hl.rs
+++ b/src/libstd/uv_hl.rs
@@ -6,7 +6,7 @@ provide a high-level, abstracted interface to some set of
 libuv functionality.
 "];
 
-export high_level_loop, high_level_msg;
+export high_level_loop, hl_loop_ext, high_level_msg;
 export run_high_level_loop, interact, ref_handle, unref_handle;
 
 import ll = uv_ll;
@@ -22,10 +22,39 @@ the C uv loop to process any pending callbacks
 * op_chan - a channel used to send function callbacks to be processed
 by the C uv loop
 "]
-type high_level_loop = {
-    async_handle: **ll::uv_async_t,
-    op_chan: comm::chan<high_level_msg>
-};
+enum high_level_loop {
+    single_task_loop({
+        async_handle: **ll::uv_async_t,
+        op_chan: comm::chan<high_level_msg>
+    }),
+    monitor_task_loop({
+        op_chan: comm::chan<high_level_msg>
+    })
+}
+
+impl hl_loop_ext for high_level_loop {
+    fn async_handle() -> **ll::uv_async_t {
+        alt self {
+          single_task_loop({async_handle, op_chan}) {
+            ret async_handle;
+          }
+          _ {
+            fail "variant of hl::high_level_loop that doesn't include" +
+                "an async_handle field";
+          }
+        }
+    }
+    fn op_chan() -> comm::chan<high_level_msg> {
+        alt self {
+          single_task_loop({async_handle, op_chan}) {
+            ret op_chan;
+          }
+          monitor_task_loop({op_chan}) {
+            ret op_chan;
+          }
+        }
+    }
+}
 
 #[doc="
 Represents the range of interactions with a `high_level_loop`
@@ -158,15 +187,15 @@ enum global_loop_data {
 
 unsafe fn send_high_level_msg(hl_loop: high_level_loop,
                               -msg: high_level_msg) unsafe {
-    comm::send(hl_loop.op_chan, msg);
+    comm::send(hl_loop.op_chan(), msg);
 
     // if the global async handle == 0, then that means
     // 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) {
+    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));
+        ll::async_send(*(hl_loop.async_handle()));
     }
     else {
         log(debug,"GLOBAL ASYNC handle == 0");