auto merge of #6577 : brson/rust/io-upstream, r=pcwalton

r?

This is all of my scheduler work on #4419 from the last 3 weeks or so. I've had a few failed pull requests so far but I think the problems are ironed out.

* TCP
* The beginnings of runtime embedding APIs
* Porting various corners of core to be compatible with both schedulers
* libuv timer bindings
* Further refinement of I/O error handling, including a new, incomplete, `read_error` condition
* Incomplete refactoring to make tasks work without coroutines and user-space scheduling
* Implementations of Reader/Writer extension methods
* Implementations of the most important part of core::comm

I'm particularly happy with how easy the [comm types on top of the scheduler](https://github.com/brson/rust/blob/io-upstream/src/libcore/rt/comm.rs). Note that these implementations do not use pipes. If anything here needs careful review though it's this code.

This branch passes 95% of the run-pass tests (with `TESTARGS=--newrt`)

In the next week I'll probably spend some time adding preliminary multithreading and seeing how close we are to removing the old runtime.

1 files changed, 16 insertions, 0 deletions

diff --git a/src/rt/rust_env.cpp b/src/rt/rust_env.cpp
index 360d6114928..ed38be3550f 100644
--- a/src/rt/rust_env.cpp
+++ b/src/rt/rust_env.cpp
@@ -13,6 +13,7 @@
 // that might come from the environment is loaded here, once, during
 // init.
 
+#include "sync/lock_and_signal.h"
 #include "rust_env.h"
 
 // The environment variables that the runtime knows about
@@ -26,6 +27,18 @@
 #define RUST_DEBUG_MEM "RUST_DEBUG_MEM"
 #define RUST_DEBUG_BORROW "RUST_DEBUG_BORROW"
 
+static lock_and_signal env_lock;
+
+extern "C" CDECL void
+rust_take_env_lock() {
+    env_lock.lock();
+}
+
+extern "C" CDECL void
+rust_drop_env_lock() {
+    env_lock.unlock();
+}
+
 #if defined(__WIN32__)
 static int
 get_num_cpus() {
@@ -119,6 +132,8 @@ copyenv(const char* name) {
 
 rust_env*
 load_env(int argc, char **argv) {
+    scoped_lock with(env_lock);
+
     rust_env *env = (rust_env*)malloc(sizeof(rust_env));
 
     env->num_sched_threads = (size_t)get_num_threads();
@@ -141,3 +156,4 @@ free_env(rust_env *env) {
     free(env->rust_seed);
     free(env);
 }
+