---

yaml
---
r: 98293
b: refs/heads/master
c: 40df5a2
h: refs/heads/master
i:
  98291: a274229
v: v3

Author: bors

[refs]

@@ -1,5 +1,5 @@
 ---
-refs/heads/master: cb12de14c92526930aa9c55e660fe2f7350fb56a
+refs/heads/master: 40df5a2e9ac81f445c7122a484618918b752a1e2
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
 refs/heads/snap-stage3: b6400f998497c3958f40997a71756ead344a776d
 refs/heads/try: c274a6888410ce3e357e014568b43310ed787d36

trunk/doc/guide-ffi.md

@@ -249,6 +249,143 @@ fn main() {
 }
 ~~~~
 
+# Callbacks from C code to Rust functions
+
+Some external libraries require the usage of callbacks to report back their
+current state or intermediate data to the caller.
+It is possible to pass functions defined in Rust to an external library.
+The requirement for this is that the callback function is marked as `extern`
+with the correct calling convention to make it callable from C code.
+
+The callback function that can then be sent to through a registration call
+to the C library and afterwards be invoked from there.
+
+A basic example is:
+
+Rust code:
+~~~~ {.xfail-test}
+extern fn callback(a:i32) {
+    println!("I'm called from C with value {0}", a);
+}
+
+#[link(name = "extlib")]
+extern {
+   fn register_callback(cb: extern "C" fn(i32)) -> i32;
+   fn trigger_callback();
+}
+
+fn main() {
+    unsafe {
+        register_callback(callback);
+        trigger_callback(); // Triggers the callback
+    }
+}
+~~~~
+
+C code:
+~~~~ {.xfail-test}
+typedef void (*rust_callback)(int32_t);
+rust_callback cb;
+
+int32_t register_callback(rust_callback callback) {
+    cb = callback;
+    return 1;
+}
+
+void trigger_callback() {
+  cb(7); // Will call callback(7) in Rust
+}
+~~~~
+
+In this example will Rust's `main()` will call `do_callback()` in C,
+which would call back to `callback()` in Rust.
+
+
+## Targetting callbacks to Rust objects
+
+The former example showed how a global function can be called from C-Code.
+However it is often desired that the callback is targetted to a special
+Rust object. This could be the object that represents the wrapper for the
+respective C object. 
+
+This can be achieved by passing an unsafe pointer to the object down to the
+C library. The C library can then include the pointer to the Rust object in
+the notification. This will provide a unsafe possibility to access the 
+referenced Rust object in callback.
+
+Rust code:
+~~~~ {.xfail-test}
+
+struct RustObject {
+    a: i32,
+    // other members
+}
+
+extern fn callback(target: *RustObject, a:i32) {
+    println!("I'm called from C with value {0}", a);
+    (*target).a = a; // Update the value in RustObject with the value received from the callback
+}
+
+#[link(name = "extlib")]
+extern {
+   fn register_callback(target: *RustObject, cb: extern "C" fn(*RustObject, i32)) -> i32;
+   fn trigger_callback();
+}
+
+fn main() {
+    // Create the object that will be referenced in the callback
+    let rust_object = ~RustObject{a: 5, ...};
+     
+    unsafe {
+        // Gets a raw pointer to the object
+        let target_addr:*RustObject = ptr::to_unsafe_ptr(rust_object);
+        register_callback(target_addr, callback);
+        trigger_callback(); // Triggers the callback
+    }
+}
+~~~~
+
+C code:
+~~~~ {.xfail-test}
+typedef void (*rust_callback)(int32_t);
+void* cb_target;
+rust_callback cb;
+
+int32_t register_callback(void* callback_target, rust_callback callback) {
+    cb_target = callback_target;
+    cb = callback;
+    return 1;
+}
+
+void trigger_callback() {
+  cb(cb_target, 7); // Will call callback(&rustObject, 7) in Rust
+}
+~~~~
+
+## Asynchronous callbacks
+
+In the already given examples the callbacks are invoked as a direct reaction
+to a function call to the external C library.
+The control over the current thread switched from Rust to C to Rust for the
+execution of the callback, but in the end the callback is executed on the
+same thread (and Rust task) that lead called the function which triggered
+the callback.
+
+Things get more complicated when the external library spawns it's own threads
+and invokes callbacks from there.
+In these cases access to Rust data structures inside he callbacks is
+especially unsafe and proper synchronization mechanisms must be used.
+Besides classical synchronization mechanisms like mutexes one possibility in
+Rust is to use channels (in `std::comm`) to forward data from the C thread
+that invoked the callback into a Rust task.
+
+If an asychronous callback targets a special object in the Rust address space
+it is also absolutely necessary that no more callbacks are performed by the 
+C library after the respective Rust object get's destroyed. 
+This can be achieved by unregistering the callback it the object's
+destructor and designing the library in a way that guarantees that no
+callback will be performed after unregistration.
+
 # Linking
 
 The `link` attribute on `extern` blocks provides the basic building block for

trunk/doc/rust.md

@@ -484,6 +484,7 @@ include:
 
 * `fmt!` : format data into a string
 * `env!` : look up an environment variable's value at compile time
+* `file!`: return the path to the file being compiled
 * `stringify!` : pretty-print the Rust expression given as an argument
 * `include!` : include the Rust expression in the given file
 * `include_str!` : include the contents of the given file as a string

trunk/src/librustc/metadata/encoder.rs

@@ -1720,6 +1720,7 @@ impl<'a, 'b> Visitor<()> for MacroDefVisitor<'a, 'b> {
             }
             _ => {}
         }
+        visit::walk_item(self, item, ());
     }
 }
 

trunk/src/librustc/middle/borrowck/doc.rs

@@ -179,7 +179,7 @@ checker uses a data flow propagation to compute the full set of loans
 in scope at each expression and then uses that set to decide whether
 that expression is legal.  Remember that the scope of loan is defined
 by its lifetime LT.  We sometimes say that a loan which is in-scope at
-a particular point is an "outstanding loan", aand the set of
+a particular point is an "outstanding loan", and the set of
 restrictions included in those loans as the "outstanding
 restrictions".
 

trunk/src/librustc/middle/check_const.rs

@@ -177,11 +177,10 @@ pub fn check_expr(v: &mut CheckCrateVisitor,
                 }
             }
           }
-          ExprParen(e) => { check_expr(v, sess, def_map, method_map,
-                                        tcx, e, is_const); }
           ExprVstore(_, ExprVstoreSlice) |
           ExprVec(_, MutImmutable) |
           ExprAddrOf(MutImmutable, _) |
+          ExprParen(..) |
           ExprField(..) |
           ExprIndex(..) |
           ExprTup(..) |

trunk/src/librustc/middle/moves.rs

@@ -38,7 +38,7 @@ case, the value is read, and the container (`x`) is also read.
 In the second case, `y`, `x.b` is being assigned which has type
 `~int`.  Because this type moves by default, that will be a move
 reference.  Whenever we move from a compound expression like `x.b` (or
-`x[b]` or `*x` or `{x)[b].c`, etc), this invalidates all containing
+`x[b]` or `*x` or `{x}[b].c`, etc), this invalidates all containing
 expressions since we do not currently permit "incomplete" variables
 where part of them has been moved and part has not.  In this case,
 this means that the reference to `x` is also a move.  We'll see later,
@@ -56,7 +56,7 @@ For each binding in a match or let pattern, we also compute a read
 or move designation.  A move binding means that the value will be
 moved from the value being matched.  As a result, the expression
 being matched (aka, the 'discriminant') is either moved or read
-depending on whethe the bindings move the value they bind to out of
+depending on whether the bindings move the value they bind to out of
 the discriminant.
 
 For examples, consider this match expression:

trunk/src/test/auxiliary/macro_export_inner_module.rs

@@ -0,0 +1,18 @@
+// Copyright 2014 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.
+
+#[feature(macro_rules)];
+
+pub mod inner {
+    #[macro_export]
+    macro_rules! foo(
+        () => (1)
+    )
+}

trunk/src/test/run-pass/macro-export-inner-module.rs

@@ -0,0 +1,22 @@
+// Copyright 2014 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.
+
+//aux-build:macro_export_inner_module.rs
+//xfail-stage1
+//xfail-fast
+
+#[feature(phase)];
+
+#[phase(syntax)]
+extern mod macro_export_inner_module;
+
+pub fn main() {
+    assert_eq!(1, foo!());
+}

trunk/src/test/run-pass/super-fast-paren-parsing.rs

@@ -0,0 +1,25 @@
+// Copyright 2014 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.
+
+static a: int =
+(((((((((((((((((((((((((((((((((((((((((((((((((((
+(((((((((((((((((((((((((((((((((((((((((((((((((((
+(((((((((((((((((((((((((((((((((((((((((((((((((((
+(((((((((((((((((((((((((((((((((((((((((((((((((((
+(((((((((((((((((((((((((((((((((((((((((((((((((((
+1
+)))))))))))))))))))))))))))))))))))))))))))))))))))
+)))))))))))))))))))))))))))))))))))))))))))))))))))
+)))))))))))))))))))))))))))))))))))))))))))))))))))
+)))))))))))))))))))))))))))))))))))))))))))))))))))
+)))))))))))))))))))))))))))))))))))))))))))))))))))
+;
+
+pub fn main() {}