std::rt: Support os::args

Author: brson

src/libstd/os.rs

@@ -40,6 +40,8 @@ use option::{Some, None};
 use os;
 use prelude::*;
 use ptr;
+use rt;
+use rt::TaskContext;
 use str;
 use uint;
 use unstable::finally::Finally;
@@ -1167,10 +1169,17 @@ pub fn real_args() -> ~[~str] {
 #[cfg(target_os = "android")]
 #[cfg(target_os = "freebsd")]
 pub fn real_args() -> ~[~str] {
-    unsafe {
-        let argc = rustrt::rust_get_argc();
-        let argv = rustrt::rust_get_argv();
-        load_argc_and_argv(argc, argv)
+    if rt::context() == TaskContext {
+        match rt::args::clone() {
+            Some(args) => args,
+            None => fail!("process arguments not initialized")
+        }
+    } else {
+        unsafe {
+            let argc = rustrt::rust_get_argc();
+            let argv = rustrt::rust_get_argv();
+            load_argc_and_argv(argc, argv)
+        }
     }
 }
 

src/libstd/rt/args.rs

@@ -0,0 +1,125 @@
+// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Global storage for command line arguments
+//!
+//! The current incarnation of the Rust runtime expects for
+//! the processes `argc` and `argv` arguments to be stored
+//! in a globally-accessible location for use by the `os` module.
+//!
+//! XXX: Would be nice for this to not exist.
+//! XXX: This has a lot of C glue for lack of globals.
+
+use libc;
+use option::{Option, Some, None};
+use str;
+use uint;
+use unstable::finally::Finally;
+use util;
+
+/// One-time global initialization.
+pub unsafe fn init(argc: int, argv: **u8) {
+    let args = load_argc_and_argv(argc, argv);
+    put(args);
+}
+
+/// One-time global cleanup.
+pub fn cleanup() {
+    rtassert!(take().is_some());
+}
+
+/// Take the global arguments from global storage.
+pub fn take() -> Option<~[~str]> {
+    with_lock(|| unsafe {
+        let ptr = get_global_ptr();
+        let val = util::replace(&mut *ptr, None);
+        val.map(|s: &~~[~str]| (**s).clone())
+    })
+}
+
+/// Give the global arguments to global storage.
+///
+/// It is an error if the arguments already exist.
+pub fn put(args: ~[~str]) {
+    with_lock(|| unsafe {
+        let ptr = get_global_ptr();
+        rtassert!((*ptr).is_none());
+        (*ptr) = Some(~args.clone());
+    })
+}
+
+/// Make a clone of the global arguments.
+pub fn clone() -> Option<~[~str]> {
+    with_lock(|| unsafe {
+        let ptr = get_global_ptr();
+        (*ptr).map(|s: &~~[~str]| (**s).clone())
+    })
+}
+
+fn with_lock<T>(f: &fn() -> T) -> T {
+    do (|| {
+        unsafe {
+            rust_take_global_args_lock();
+            f()
+        }
+    }).finally {
+        unsafe {
+            rust_drop_global_args_lock();
+        }
+    }
+}
+
+fn get_global_ptr() -> *mut Option<~~[~str]> {
+    unsafe { rust_get_global_args_ptr() }
+}
+
+// Copied from `os`.
+unsafe fn load_argc_and_argv(argc: int, argv: **u8) -> ~[~str] {
+    let mut args = ~[];
+    for uint::range(0, argc as uint) |i| {
+        args.push(str::raw::from_c_str(*(argv as **libc::c_char).offset(i)));
+    }
+    return args;
+}
+
+extern {
+    fn rust_take_global_args_lock();
+    fn rust_drop_global_args_lock();
+    fn rust_get_global_args_ptr() -> *mut Option<~~[~str]>;
+}
+
+#[cfg(test)]
+mod tests {
+    use option::{Some, None};
+    use super::*;
+    use unstable::finally::Finally;
+
+    #[test]
+    fn smoke_test() {
+        // Preserve the actual global state.
+        let saved_value = take();
+
+        let expected = ~[~"happy", ~"today?"];
+
+        put(expected.clone());
+        assert!(clone() == Some(expected.clone()));
+        assert!(take() == Some(expected.clone()));
+        assert!(take() == None);
+
+        do (|| {
+        }).finally {
+            // Restore the actual global state.
+            match saved_value {
+                Some(ref args) => put(args.clone()),
+                None => ()
+            }
+        }
+    }
+}

src/libstd/rt/mod.rs

@@ -159,6 +159,9 @@ pub mod metrics;
 /// Just stuff
 pub mod util;
 
+// Global command line argument storage
+pub mod args;
+
 /// Set up a default runtime configuration, given compiler-supplied arguments.
 ///
 /// This is invoked by the `start` _language item_ (unstable::lang) to
@@ -173,20 +176,28 @@ pub mod util;
 /// # Return value
 ///
 /// The return value is used as the process return code. 0 on success, 101 on error.
-pub fn start(_argc: int, _argv: **u8, crate_map: *u8, main: ~fn()) -> int {
+pub fn start(argc: int, argv: **u8, crate_map: *u8, main: ~fn()) -> int {
 
-    init(crate_map);
+    init(argc, argv, crate_map);
     let exit_code = run(main);
     cleanup();
 
     return exit_code;
 }
 
-/// One-time runtime initialization. Currently all this does is set up logging
-/// based on the RUST_LOG environment variable.
-pub fn init(crate_map: *u8) {
-    logging::init(crate_map);
-    unsafe { rust_update_gc_metadata(crate_map) }
+/// One-time runtime initialization.
+///
+/// Initializes global state, including frobbing
+/// the crate's logging flags, registering GC
+/// metadata, and storing the process arguments.
+pub fn init(argc: int, argv: **u8, crate_map: *u8) {
+    // XXX: Derefing these pointers is not safe.
+    // Need to propagate the unsafety to `start`.
+    unsafe {
+        args::init(argc, argv);
+        logging::init(crate_map);
+        rust_update_gc_metadata(crate_map);
+    }
 
     extern {
         fn rust_update_gc_metadata(crate_map: *u8);
@@ -195,6 +206,7 @@ pub fn init(crate_map: *u8) {
 
 /// One-time runtime cleanup.
 pub fn cleanup() {
+    args::cleanup();
     global_heap::cleanup();
 }
 

src/rt/rust_builtin.cpp

@@ -932,6 +932,24 @@ rust_get_num_cpus() {
     return get_num_cpus();
 }
 
+static lock_and_signal global_args_lock;
+static uintptr_t global_args_ptr = 0;
+
+extern "C" CDECL void
+rust_take_global_args_lock() {
+    global_args_lock.lock();
+}
+
+extern "C" CDECL void
+rust_drop_global_args_lock() {
+    global_args_lock.unlock();
+}
+
+extern "C" CDECL uintptr_t*
+rust_get_global_args_ptr() {
+    return &global_args_ptr;
+}
+
 //
 // Local Variables:
 // mode: C++

src/rt/rustrt.def.in

@@ -242,3 +242,4 @@ rust_drop_env_lock
 rust_update_log_settings
 rust_running_on_valgrind
 rust_get_num_cpus
+rust_get_global_args_ptr