green: Remove the dependence on the crate map

This is the final nail in the coffin for the crate map. The `start` function for
libgreen now has a new added parameter which is the event loop factory instead
of inferring it from the crate map. The two current valid values for this
parameter are `green::basic::event_loop` and `rustuv::event_loop`.

Author: alexcrichton

src/compiletest/compiletest.rs

@@ -44,7 +44,9 @@ pub mod common;
 pub mod errors;
 
 #[start]
-fn start(argc: int, argv: **u8) -> int { green::start(argc, argv, main) }
+fn start(argc: int, argv: **u8) -> int {
+    green::start(argc, argv, rustuv::event_loop, main)
+}
 
 pub fn main() {
     let args = os::args();

src/libgreen/basic.rs

@@ -237,7 +237,7 @@ mod test {
     fn pool() -> SchedPool {
         SchedPool::new(PoolConfig {
             threads: 1,
-            event_loop_factory: Some(basic::event_loop),
+            event_loop_factory: basic::event_loop,
         })
     }
 
@@ -267,7 +267,7 @@ mod test {
     fn multi_thread() {
         let mut pool = SchedPool::new(PoolConfig {
             threads: 2,
-            event_loop_factory: Some(basic::event_loop),
+            event_loop_factory: basic::event_loop,
         });
 
         for _ in range(0, 20) {

src/libgreen/lib.rs

@@ -116,13 +116,34 @@
 //! extern crate green;
 //!
 //! #[start]
-//! fn start(argc: int, argv: **u8) -> int { green::start(argc, argv, main) }
+//! fn start(argc: int, argv: **u8) -> int {
+//!     green::start(argc, argv, green::basic::event_loop, main)
+//! }
 //!
 //! fn main() {
 //!     // this code is running in a pool of schedulers
 //! }
 //! ```
 //!
+//! > **Note**: This `main` funciton in this example does *not* have I/O
+//! >           support. The basic event loop does not provide any support
+//!
+//! # Starting with I/O support in libgreen
+//!
+//! ```rust
+//! extern crate green;
+//! extern crate rustuv;
+//!
+//! #[start]
+//! fn start(argc: int, argv: **u8) -> int {
+//!     green::start(argc, argv, rustuv::event_loop, main)
+//! }
+//!
+//! fn main() {
+//!     // this code is running in a pool of schedulers all powered by libuv
+//! }
+//! ```
+//!
 //! # Using a scheduler pool
 //!
 //! ```rust
@@ -176,11 +197,11 @@
 #[allow(visible_private_types)];
 
 #[cfg(test)] #[phase(syntax, link)] extern crate log;
+#[cfg(test)] extern crate rustuv;
 extern crate rand;
 
 use std::mem::replace;
 use std::os;
-use std::rt::crate_map;
 use std::rt::rtio;
 use std::rt::thread::Thread;
 use std::rt;
@@ -207,16 +228,6 @@ pub mod sleeper_list;
 pub mod stack;
 pub mod task;
 
-#[lang = "start"]
-#[cfg(not(test), stage0)]
-pub fn lang_start(main: *u8, argc: int, argv: **u8) -> int {
-    use std::cast;
-    start(argc, argv, proc() {
-        let main: extern "Rust" fn() = unsafe { cast::transmute(main) };
-        main();
-    })
-}
-
 /// Set up a default runtime configuration, given compiler-supplied arguments.
 ///
 /// This function will block until the entire pool of M:N schedulers have
@@ -235,12 +246,14 @@ pub fn lang_start(main: *u8, argc: int, argv: **u8) -> int {
 ///
 /// The return value is used as the process return code. 0 on success, 101 on
 /// error.
-pub fn start(argc: int, argv: **u8, main: proc()) -> int {
+pub fn start(argc: int, argv: **u8,
+             event_loop_factory: fn() -> ~rtio::EventLoop,
+             main: proc()) -> int {
     rt::init(argc, argv);
     let mut main = Some(main);
     let mut ret = None;
     simple::task().run(|| {
-        ret = Some(run(main.take_unwrap()));
+        ret = Some(run(event_loop_factory, main.take_unwrap()));
     });
     // unsafe is ok b/c we're sure that the runtime is gone
     unsafe { rt::cleanup() }
@@ -255,10 +268,12 @@ pub fn start(argc: int, argv: **u8, main: proc()) -> int {
 ///
 /// This function will not return until all schedulers in the associated pool
 /// have returned.
-pub fn run(main: proc()) -> int {
+pub fn run(event_loop_factory: fn() -> ~rtio::EventLoop, main: proc()) -> int {
     // Create a scheduler pool and spawn the main task into this pool. We will
     // get notified over a channel when the main task exits.
-    let mut pool = SchedPool::new(PoolConfig::new());
+    let mut cfg = PoolConfig::new();
+    cfg.event_loop_factory = event_loop_factory;
+    let mut pool = SchedPool::new(cfg);
     let (tx, rx) = channel();
     let mut opts = TaskOpts::new();
     opts.notify_chan = Some(tx);
@@ -283,7 +298,7 @@ pub struct PoolConfig {
     threads: uint,
     /// A factory function used to create new event loops. If this is not
     /// specified then the default event loop factory is used.
-    event_loop_factory: Option<fn() -> ~rtio::EventLoop>,
+    event_loop_factory: fn() -> ~rtio::EventLoop,
 }
 
 impl PoolConfig {
@@ -292,7 +307,7 @@ impl PoolConfig {
     pub fn new() -> PoolConfig {
         PoolConfig {
             threads: rt::default_sched_threads(),
-            event_loop_factory: None,
+            event_loop_factory: basic::event_loop,
         }
     }
 }
@@ -334,7 +349,6 @@ impl SchedPool {
             threads: nscheds,
             event_loop_factory: factory
         } = config;
-        let factory = factory.unwrap_or(default_event_loop_factory());
         assert!(nscheds > 0);
 
         // The pool of schedulers that will be returned from this function
@@ -503,20 +517,3 @@ impl Drop for SchedPool {
         }
     }
 }
-
-fn default_event_loop_factory() -> fn() -> ~rtio::EventLoop {
-    match crate_map::get_crate_map() {
-        None => {}
-        Some(map) => {
-            match map.event_loop_factory {
-                None => {}
-                Some(factory) => return factory
-            }
-        }
-    }
-
-    // If the crate map didn't specify a factory to create an event loop, then
-    // instead just use a basic event loop missing all I/O services to at least
-    // get the scheduler running.
-    return basic::event_loop;
-}

src/libgreen/sched.rs

@@ -1003,6 +1003,8 @@ fn new_sched_rng() -> XorShiftRng {
 
 #[cfg(test)]
 mod test {
+    use rustuv;
+
     use std::comm;
     use std::task::TaskOpts;
     use std::rt::Runtime;
@@ -1017,7 +1019,7 @@ mod test {
     fn pool() -> SchedPool {
         SchedPool::new(PoolConfig {
             threads: 1,
-            event_loop_factory: Some(basic::event_loop),
+            event_loop_factory: basic::event_loop,
         })
     }
 
@@ -1262,7 +1264,7 @@ mod test {
 
         let mut pool = SchedPool::new(PoolConfig {
             threads: 2,
-            event_loop_factory: None,
+            event_loop_factory: rustuv::event_loop,
         });
 
         // This is a regression test that when there are no schedulable tasks in
@@ -1413,7 +1415,7 @@ mod test {
     fn dont_starve_1() {
         let mut pool = SchedPool::new(PoolConfig {
             threads: 2, // this must be > 1
-            event_loop_factory: Some(basic::event_loop),
+            event_loop_factory: basic::event_loop,
         });
         pool.spawn(TaskOpts::new(), proc() {
             let (tx, rx) = channel();

src/libgreen/task.rs

@@ -494,7 +494,7 @@ mod tests {
     fn spawn_opts(opts: TaskOpts, f: proc()) {
         let mut pool = SchedPool::new(PoolConfig {
             threads: 1,
-            event_loop_factory: None,
+            event_loop_factory: ::rustuv::event_loop,
         });
         pool.spawn(opts, f);
         pool.shutdown();

src/libnative/lib.rs

@@ -69,7 +69,7 @@ static OS_DEFAULT_STACK_ESTIMATE: uint = 1 << 20;
 static OS_DEFAULT_STACK_ESTIMATE: uint = 2 * (1 << 20);
 
 #[lang = "start"]
-#[cfg(not(test), not(stage0))]
+#[cfg(not(test))]
 pub fn lang_start(main: *u8, argc: int, argv: **u8) -> int {
     use std::cast;
     start(argc, argv, proc() {

src/librustuv/homing.rs

@@ -167,7 +167,7 @@ mod test {
         let (tx, rx) = channel();
         let mut pool = SchedPool::new(PoolConfig {
             threads: 1,
-            event_loop_factory: None,
+            event_loop_factory: ::event_loop,
         });
 
         pool.spawn(TaskOpts::new(), proc() {
@@ -188,7 +188,7 @@ mod test {
         let (tx, rx) = channel();
         let mut pool = SchedPool::new(PoolConfig {
             threads: 1,
-            event_loop_factory: None,
+            event_loop_factory: ::event_loop,
         });
 
         pool.spawn(TaskOpts::new(), proc() {

src/librustuv/lib.rs

@@ -54,6 +54,7 @@ use std::libc::{c_int, c_void};
 use std::ptr::null;
 use std::ptr;
 use std::rt::local::Local;
+use std::rt::rtio;
 use std::rt::task::{BlockedTask, Task};
 use std::str::raw::from_c_str;
 use std::str;
@@ -76,7 +77,7 @@ pub use self::tty::TtyWatcher;
 //        '__test' module.
 #[cfg(test)] #[start]
 fn start(argc: int, argv: **u8) -> int {
-    green::start(argc, argv, __test::main)
+    green::start(argc, argv, event_loop, __test::main)
 }
 
 mod macros;
@@ -104,6 +105,31 @@ pub mod tty;
 pub mod signal;
 pub mod stream;
 
+/// Creates a new event loop which is powered by libuv
+///
+/// This function is used in tandem with libgreen's `PoolConfig` type as a value
+/// for the `event_loop_factory` field. Using this function as the event loop
+/// factory will power programs with libuv and enable green threading.
+///
+/// # Example
+///
+/// ```
+/// extern crate rustuv;
+/// extern crate green;
+///
+/// #[start]
+/// fn start(argc: int, argv: **u8) -> int {
+///     green::start(argc, argv, rustuv::event_loop, main)
+/// }
+///
+/// fn main() {
+///     // this code is running inside of a green task powered by libuv
+/// }
+/// ```
+pub fn event_loop() -> ~rtio::EventLoop {
+    ~uvio::UvEventLoop::new() as ~rtio::EventLoop
+}
+
 /// A type that wraps a uv handle
 pub trait UvHandle<T> {
     fn uv_handle(&self) -> *T;

src/librustuv/uvio.rs

@@ -105,12 +105,6 @@ impl rtio::EventLoop for UvEventLoop {
     }
 }
 
-#[cfg(not(test))]
-#[lang = "event_loop_factory"]
-pub fn new_loop() -> ~rtio::EventLoop {
-    ~UvEventLoop::new() as ~rtio::EventLoop
-}
-
 #[test]
 fn test_callback_run_once() {
     use std::rt::rtio::EventLoop;

src/libstd/lib.rs

@@ -84,7 +84,7 @@
 //        '__test' module.
 #[cfg(test)] #[start]
 fn start(argc: int, argv: **u8) -> int {
-    green::start(argc, argv, __test::main)
+    green::start(argc, argv, rustuv::event_loop, __test::main)
 }
 
 pub mod macros;