From e4c291530e4cc160eca30811e17d614f236147a4 Mon Sep 17 00:00:00 2001
From: Eric Holk <eric.holk@gmail.com>
Date: Thu, 7 Jun 2012 12:18:34 -0700
Subject: [PATCH] Basic functionality for new ports and chans

The first benchmark shows about twice the throughput of the old system.
---
 src/libcore/arc.rs     | 17 +++++---
 src/libcore/core.rc    |  3 +-
 src/libcore/dvec.rs    | 50 +++++++++++++++---------
 src/libcore/newcomm.rs | 88 ++++++++++++++++++++++++++++++++++++++++++
 src/libcore/vec.rs     | 24 ++++++++----
 5 files changed, 149 insertions(+), 33 deletions(-)
 create mode 100644 src/libcore/newcomm.rs

diff --git a/src/libcore/arc.rs b/src/libcore/arc.rs
index a6baae0d082..2fa656f3eeb 100644
--- a/src/libcore/arc.rs
+++ b/src/libcore/arc.rs
@@ -28,6 +28,7 @@ resource arc_destruct<T>(data: *libc::c_void) {
     unsafe {
         let data: ~arc_data<T> = unsafe::reinterpret_cast(data);
         let new_count = rustrt::rust_atomic_decrement(&mut data.count);
+        let data_ptr : *() = unsafe::reinterpret_cast(data);
         assert new_count >= 0;
         if new_count == 0 {
             // drop glue takes over.
@@ -68,17 +69,19 @@ allowing them to share the underlying data."]
 fn clone<T: const>(rc: &arc<T>) -> arc<T> {
     unsafe {
         let ptr: ~arc_data<T> = unsafe::reinterpret_cast(**rc);
-        rustrt::rust_atomic_increment(&mut ptr.count);
+        let new_count = rustrt::rust_atomic_increment(&mut ptr.count);
+        let data_ptr : *() = unsafe::reinterpret_cast(ptr);
+        assert new_count >= 2;
         unsafe::forget(ptr);
     }
     arc_destruct(**rc)
 }
 
 // An arc over mutable data that is protected by a lock.
-type ex_data<T> = {lock: sys::lock_and_signal, data: T};
-type exclusive<T> = arc_destruct<ex_data<T>>;
+type ex_data<T: send> = {lock: sys::lock_and_signal, data: T};
+type exclusive<T: send> = arc_destruct<ex_data<T>>;
 
-fn exclusive<T>(-data: T) -> exclusive<T> {
+fn exclusive<T:send >(-data: T) -> exclusive<T> {
     let data = ~{mut count: 1, data: {lock: sys::create_lock(),
                                       data: data}};
     unsafe {
@@ -88,12 +91,14 @@ fn exclusive<T>(-data: T) -> exclusive<T> {
     }
 }
 
-impl methods<T> for exclusive<T> {
+impl methods<T: send> for exclusive<T> {
     fn clone() -> exclusive<T> {
         unsafe {
             // this makes me nervous...
             let ptr: ~arc_data<ex_data<T>> = unsafe::reinterpret_cast(*self);
-            rustrt::rust_atomic_increment(&mut ptr.count);
+            let new_count = rustrt::rust_atomic_increment(&mut ptr.count);
+            let data_ptr : *() = unsafe::reinterpret_cast(ptr);
+            assert new_count > 1;
             unsafe::forget(ptr);
         }
         arc_destruct(*self)
diff --git a/src/libcore/core.rc b/src/libcore/core.rc
index 913832a7f07..3185d8e30c0 100644
--- a/src/libcore/core.rc
+++ b/src/libcore/core.rc
@@ -39,7 +39,7 @@ export float, f32, f64;
 export box, char, str, ptr, vec, bool;
 export either, option, result, iter;
 export libc, os, io, run, rand, sys, unsafe, logging;
-export arc, comm, task, future;
+export arc, newcomm, comm, task, future;
 export extfmt;
 export tuple;
 export to_str;
@@ -176,6 +176,7 @@ mod dvec_iter {
 
 // Concurrency
 mod arc;
+mod newcomm;
 mod comm;
 mod task;
 mod future;
diff --git a/src/libcore/dvec.rs b/src/libcore/dvec.rs
index d30179fd881..85d61d3f606 100644
--- a/src/libcore/dvec.rs
+++ b/src/libcore/dvec.rs
@@ -132,14 +132,6 @@ impl extensions<A> for dvec<A> {
         self.check_not_borrowed();
         self.data <- w;
     }
-}
-
-impl extensions<A:copy> for dvec<A> {
-    #[doc = "Append a single item to the end of the list"]
-    fn push(t: A) {
-        self.check_not_borrowed();
-        vec::push(self.data, t);
-    }
 
     #[doc = "Remove and return the last element"]
     fn pop() -> A {
@@ -151,6 +143,38 @@ impl extensions<A:copy> for dvec<A> {
         }
     }
 
+    #[doc = "Insert a single item at the front of the list"]
+    fn unshift(-t: A) {
+        unsafe {
+            let mut data = unsafe::reinterpret_cast(null::<()>());
+            data <-> self.data;
+            let data_ptr: *() = unsafe::reinterpret_cast(data);
+            if data_ptr.is_null() { fail "Recursive use of dvec"; }
+            log(error, "a");
+            self.data <- [mut t] + data;
+            log(error, "b");
+        }
+    }
+
+    #[doc = "Append a single item to the end of the list"]
+    fn push(+t: A) {
+        self.check_not_borrowed();
+        vec::push(self.data, t);
+    }
+
+
+    #[doc = "Remove and return the first element"]
+    fn shift() -> A {
+        self.borrow { |v|
+            let mut v = vec::from_mut(v);
+            let result = vec::shift(v);
+            self.return(vec::to_mut(v));
+            result
+        }
+    }
+}
+
+impl extensions<A:copy> for dvec<A> {
     #[doc = "
         Append all elements of a vector to the end of the list
 
@@ -213,16 +237,6 @@ impl extensions<A:copy> for dvec<A> {
         }
     }
 
-    #[doc = "Remove and return the first element"]
-    fn shift() -> A {
-        self.borrow { |v|
-            let mut v = vec::from_mut(v);
-            let result = vec::shift(v);
-            self.return(vec::to_mut(v));
-            result
-        }
-    }
-
     #[doc = "Copy out an individual element"]
     #[inline(always)]
     fn [](idx: uint) -> A {
diff --git a/src/libcore/newcomm.rs b/src/libcore/newcomm.rs
new file mode 100644
index 00000000000..6934dba84cd
--- /dev/null
+++ b/src/libcore/newcomm.rs
@@ -0,0 +1,88 @@
+#[doc="A new implementation of communication.
+
+This should be implementing almost entirely in Rust, and hopefully
+avoid needing a single global lock."]
+
+import arc::methods;
+import dvec::dvec;
+import dvec::{extensions};
+
+export port;
+export chan;
+export send, recv;
+export methods;
+
+type raw_port<T: send> = arc::exclusive<dvec<T>>;
+
+enum port<T: send> {
+    port_(raw_port<T>)
+}
+enum chan<T: send> {
+    chan_(raw_port<T>)
+}
+
+fn port<T: send>() -> port<T> {
+    port_(arc::exclusive(dvec()))
+}
+
+fn chan<T: send>(p: port<T>) -> chan<T> {
+    chan_((*p).clone())
+}
+
+fn send<T: send>(c: chan<T>, -x: T) {
+    let mut x <- some(x);
+    (*c).with {|cond, data|
+        let mut xx = none;
+        xx <-> x;
+        alt xx {
+          some(y) {
+            let mut x <- y;
+            (*data).push(x);
+            cond.signal();
+          }
+          none { fail }
+        };
+    }
+}
+
+fn recv<T: send>(p: port<T>) -> T {
+    (*p).with {|cond, data|
+        if (*data).len() == 0u {
+            cond.wait();
+        }
+        assert (*data).len() > 0u;
+        (*data).shift()
+    }
+}
+
+impl methods<T: send> for chan<T> {
+    fn send(-x: T) {
+        send(self, x)
+    }
+
+    fn clone() -> chan<T> {
+        chan_((*self).clone())
+    }
+}
+
+impl methods<T: send> for port<T> {
+    fn recv() -> T {
+        recv(self)
+    }
+
+    fn chan() -> chan<T> {
+        chan(self)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    #[test]
+    fn newport_simple() {
+        let p = port();
+        let c = chan(p);
+
+        c.send(42);
+        assert p.recv() == 42;
+    }
+}
diff --git a/src/libcore/vec.rs b/src/libcore/vec.rs
index c029e9f2448..689c641e061 100644
--- a/src/libcore/vec.rs
+++ b/src/libcore/vec.rs
@@ -371,17 +371,25 @@ fn rsplitn<T: copy>(v: [T]/&, n: uint, f: fn(T) -> bool) -> [[T]] {
 // Mutators
 
 #[doc = "Removes the first element from a vector and return it"]
-fn shift<T: copy>(&v: [T]) -> T {
+fn shift<T>(&v: [T]) -> T {
     let ln = len::<T>(v);
     assert (ln > 0u);
-    let e = v[0];
-    v = slice::<T>(v, 1u, ln);
-    ret e;
-}
 
-#[doc = "Prepend an element to a vector"]
-fn unshift<T: copy>(&v: [T], +t: T) {
-    v = [t] + v;
+    let mut vv = [];
+    v <-> vv;
+
+    unsafe {
+        let vv = unsafe::to_ptr(vv);
+        let r <- *vv;
+
+        for uint::range(1u, ln) {|i|
+            // FIXME: this isn't legal, per se...
+            let r <- *ptr::offset(vv, i);
+            push(v, r);
+        }
+
+        r
+    }
 }
 
 #[doc = "Remove the last element from a vector and return it"]