1 files changed, 500 insertions, 0 deletions
diff --git a/src/libstd/reflect.rs b/src/libstd/reflect.rs
new file mode 100644
index 00000000000..30f60dce041
--- /dev/null
+++ b/src/libstd/reflect.rs
@@ -0,0 +1,500 @@
+// Copyright 2012 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.
+
+/*!
+
+Runtime type reflection
+
+*/
+
+use intrinsic::{TyDesc, TyVisitor};
+use intrinsic::Opaque;
+use libc::c_void;
+use sys;
+use vec;
+
+/**
+ * Trait for visitor that wishes to reflect on data. To use this, create a
+ * struct that encapsulates the set of pointers you wish to walk through a
+ * data structure, and implement both `MovePtr` for it as well as `TyVisitor`;
+ * then build a MovePtrAdaptor wrapped around your struct.
+ */
+pub trait MovePtr {
+    fn move_ptr(&self, adjustment: &fn(*c_void) -> *c_void);
+    fn push_ptr(&self);
+    fn pop_ptr(&self);
+}
+
+/// Helper function for alignment calculation.
+#[inline(always)]
+pub fn align(size: uint, align: uint) -> uint {
+    ((size + align) - 1u) & !(align - 1u)
+}
+
+/// Adaptor to wrap around visitors implementing MovePtr.
+pub struct MovePtrAdaptor<V> {
+    inner: V
+}
+pub fn MovePtrAdaptor<V:TyVisitor + MovePtr>(v: V) -> MovePtrAdaptor<V> {
+    MovePtrAdaptor { inner: v }
+}
+
+pub impl<V:TyVisitor + MovePtr> MovePtrAdaptor<V> {
+    #[inline(always)]
+    fn bump(&self, sz: uint) {
+      do self.inner.move_ptr() |p| {
+            ((p as uint) + sz) as *c_void
+      };
+    }
+
+    #[inline(always)]
+    fn align(&self, a: uint) {
+      do self.inner.move_ptr() |p| {
+            align(p as uint, a) as *c_void
+      };
+    }
+
+    #[inline(always)]
+    fn align_to<T>(&self) {
+        self.align(sys::min_align_of::<T>());
+    }
+
+    #[inline(always)]
+    fn bump_past<T>(&self) {
+        self.bump(sys::size_of::<T>());
+    }
+}
+
+/// Abstract type-directed pointer-movement using the MovePtr trait
+impl<V:TyVisitor + MovePtr> TyVisitor for MovePtrAdaptor<V> {
+    fn visit_bot(&self) -> bool {
+        self.align_to::<()>();
+        if ! self.inner.visit_bot() { return false; }
+        self.bump_past::<()>();
+        true
+    }
+
+    fn visit_nil(&self) -> bool {
+        self.align_to::<()>();
+        if ! self.inner.visit_nil() { return false; }
+        self.bump_past::<()>();
+        true
+    }
+
+    fn visit_bool(&self) -> bool {
+        self.align_to::<bool>();
+        if ! self.inner.visit_bool() { return false; }
+        self.bump_past::<bool>();
+        true
+    }
+
+    fn visit_int(&self) -> bool {
+        self.align_to::<int>();
+        if ! self.inner.visit_int() { return false; }
+        self.bump_past::<int>();
+        true
+    }
+
+    fn visit_i8(&self) -> bool {
+        self.align_to::<i8>();
+        if ! self.inner.visit_i8() { return false; }
+        self.bump_past::<i8>();
+        true
+    }
+
+    fn visit_i16(&self) -> bool {
+        self.align_to::<i16>();
+        if ! self.inner.visit_i16() { return false; }
+        self.bump_past::<i16>();
+        true
+    }
+
+    fn visit_i32(&self) -> bool {
+        self.align_to::<i32>();
+        if ! self.inner.visit_i32() { return false; }
+        self.bump_past::<i32>();
+        true
+    }
+
+    fn visit_i64(&self) -> bool {
+        self.align_to::<i64>();
+        if ! self.inner.visit_i64() { return false; }
+        self.bump_past::<i64>();
+        true
+    }
+
+    fn visit_uint(&self) -> bool {
+        self.align_to::<uint>();
+        if ! self.inner.visit_uint() { return false; }
+        self.bump_past::<uint>();
+        true
+    }
+
+    fn visit_u8(&self) -> bool {
+        self.align_to::<u8>();
+        if ! self.inner.visit_u8() { return false; }
+        self.bump_past::<u8>();
+        true
+    }
+
+    fn visit_u16(&self) -> bool {
+        self.align_to::<u16>();
+        if ! self.inner.visit_u16() { return false; }
+        self.bump_past::<u16>();
+        true
+    }
+
+    fn visit_u32(&self) -> bool {
+        self.align_to::<u32>();
+        if ! self.inner.visit_u32() { return false; }
+        self.bump_past::<u32>();
+        true
+    }
+
+    fn visit_u64(&self) -> bool {
+        self.align_to::<u64>();
+        if ! self.inner.visit_u64() { return false; }
+        self.bump_past::<u64>();
+        true
+    }
+
+    fn visit_float(&self) -> bool {
+        self.align_to::<float>();
+        if ! self.inner.visit_float() { return false; }
+        self.bump_past::<float>();
+        true
+    }
+
+    fn visit_f32(&self) -> bool {
+        self.align_to::<f32>();
+        if ! self.inner.visit_f32() { return false; }
+        self.bump_past::<f32>();
+        true
+    }
+
+    fn visit_f64(&self) -> bool {
+        self.align_to::<f64>();
+        if ! self.inner.visit_f64() { return false; }
+        self.bump_past::<f64>();
+        true
+    }
+
+    fn visit_char(&self) -> bool {
+        self.align_to::<char>();
+        if ! self.inner.visit_char() { return false; }
+        self.bump_past::<char>();
+        true
+    }
+
+    fn visit_str(&self) -> bool {
+        self.align_to::<~str>();
+        if ! self.inner.visit_str() { return false; }
+        self.bump_past::<~str>();
+        true
+    }
+
+    fn visit_estr_box(&self) -> bool {
+        self.align_to::<@str>();
+        if ! self.inner.visit_estr_box() { return false; }
+        self.bump_past::<@str>();
+        true
+    }
+
+    fn visit_estr_uniq(&self) -> bool {
+        self.align_to::<~str>();
+        if ! self.inner.visit_estr_uniq() { return false; }
+        self.bump_past::<~str>();
+        true
+    }
+
+    fn visit_estr_slice(&self) -> bool {
+        self.align_to::<&'static str>();
+        if ! self.inner.visit_estr_slice() { return false; }
+        self.bump_past::<&'static str>();
+        true
+    }
+
+    fn visit_estr_fixed(&self, n: uint,
+                        sz: uint,
+                        align: uint) -> bool {
+        self.align(align);
+        if ! self.inner.visit_estr_fixed(n, sz, align) { return false; }
+        self.bump(sz);
+        true
+    }
+
+    fn visit_box(&self, mtbl: uint, inner: *TyDesc) -> bool {
+        self.align_to::<@u8>();
+        if ! self.inner.visit_box(mtbl, inner) { return false; }
+        self.bump_past::<@u8>();
+        true
+    }
+
+    fn visit_uniq(&self, mtbl: uint, inner: *TyDesc) -> bool {
+        self.align_to::<~u8>();
+        if ! self.inner.visit_uniq(mtbl, inner) { return false; }
+        self.bump_past::<~u8>();
+        true
+    }
+
+    fn visit_ptr(&self, mtbl: uint, inner: *TyDesc) -> bool {
+        self.align_to::<*u8>();
+        if ! self.inner.visit_ptr(mtbl, inner) { return false; }
+        self.bump_past::<*u8>();
+        true
+    }
+
+    fn visit_rptr(&self, mtbl: uint, inner: *TyDesc) -> bool {
+        self.align_to::<&'static u8>();
+        if ! self.inner.visit_rptr(mtbl, inner) { return false; }
+        self.bump_past::<&'static u8>();
+        true
+    }
+
+    fn visit_unboxed_vec(&self, mtbl: uint, inner: *TyDesc) -> bool {
+        self.align_to::<vec::UnboxedVecRepr>();
+        if ! self.inner.visit_vec(mtbl, inner) { return false; }
+        true
+    }
+
+    fn visit_vec(&self, mtbl: uint, inner: *TyDesc) -> bool {
+        self.align_to::<~[u8]>();
+        if ! self.inner.visit_vec(mtbl, inner) { return false; }
+        self.bump_past::<~[u8]>();
+        true
+    }
+
+    fn visit_evec_box(&self, mtbl: uint, inner: *TyDesc) -> bool {
+        self.align_to::<@[u8]>();
+        if ! self.inner.visit_evec_box(mtbl, inner) { return false; }
+        self.bump_past::<@[u8]>();
+        true
+    }
+
+    fn visit_evec_uniq(&self, mtbl: uint, inner: *TyDesc) -> bool {
+        self.align_to::<~[u8]>();
+        if ! self.inner.visit_evec_uniq(mtbl, inner) { return false; }
+        self.bump_past::<~[u8]>();
+        true
+    }
+
+    fn visit_evec_slice(&self, mtbl: uint, inner: *TyDesc) -> bool {
+        self.align_to::<&'static [u8]>();
+        if ! self.inner.visit_evec_slice(mtbl, inner) { return false; }
+        self.bump_past::<&'static [u8]>();
+        true
+    }
+
+    fn visit_evec_fixed(&self, n: uint, sz: uint, align: uint,
+                        mtbl: uint, inner: *TyDesc) -> bool {
+        self.align(align);
+        if ! self.inner.visit_evec_fixed(n, sz, align, mtbl, inner) {
+            return false;
+        }
+        self.bump(sz);
+        true
+    }
+
+    fn visit_enter_rec(&self, n_fields: uint, sz: uint, align: uint) -> bool {
+        self.align(align);
+        if ! self.inner.visit_enter_rec(n_fields, sz, align) { return false; }
+        true
+    }
+
+    fn visit_rec_field(&self, i: uint, name: &str,
+                       mtbl: uint, inner: *TyDesc) -> bool {
+        unsafe { self.align((*inner).align); }
+        if ! self.inner.visit_rec_field(i, name, mtbl, inner) {
+            return false;
+        }
+        unsafe { self.bump((*inner).size); }
+        true
+    }
+
+    fn visit_leave_rec(&self, n_fields: uint, sz: uint, align: uint) -> bool {
+        if ! self.inner.visit_leave_rec(n_fields, sz, align) { return false; }
+        true
+    }
+
+    fn visit_enter_class(&self, n_fields: uint, sz: uint, align: uint)
+                      -> bool {
+        self.align(align);
+        if ! self.inner.visit_enter_class(n_fields, sz, align) {
+            return false;
+        }
+        true
+    }
+
+    fn visit_class_field(&self, i: uint, name: &str,
+                         mtbl: uint, inner: *TyDesc) -> bool {
+        unsafe { self.align((*inner).align); }
+        if ! self.inner.visit_class_field(i, name, mtbl, inner) {
+            return false;
+        }
+        unsafe { self.bump((*inner).size); }
+        true
+    }
+
+    fn visit_leave_class(&self, n_fields: uint, sz: uint, align: uint)
+                      -> bool {
+        if ! self.inner.visit_leave_class(n_fields, sz, align) {
+            return false;
+        }
+        true
+    }
+
+    fn visit_enter_tup(&self, n_fields: uint, sz: uint, align: uint) -> bool {
+        self.align(align);
+        if ! self.inner.visit_enter_tup(n_fields, sz, align) { return false; }
+        true
+    }
+
+    fn visit_tup_field(&self, i: uint, inner: *TyDesc) -> bool {
+        unsafe { self.align((*inner).align); }
+        if ! self.inner.visit_tup_field(i, inner) { return false; }
+        unsafe { self.bump((*inner).size); }
+        true
+    }
+
+    fn visit_leave_tup(&self, n_fields: uint, sz: uint, align: uint) -> bool {
+        if ! self.inner.visit_leave_tup(n_fields, sz, align) { return false; }
+        true
+    }
+
+    fn visit_enter_fn(&self, purity: uint, proto: uint,
+                      n_inputs: uint, retstyle: uint) -> bool {
+        if ! self.inner.visit_enter_fn(purity, proto, n_inputs, retstyle) {
+            return false
+        }
+        true
+    }
+
+    fn visit_fn_input(&self, i: uint, mode: uint, inner: *TyDesc) -> bool {
+        if ! self.inner.visit_fn_input(i, mode, inner) { return false; }
+        true
+    }
+
+    fn visit_fn_output(&self, retstyle: uint, inner: *TyDesc) -> bool {
+        if ! self.inner.visit_fn_output(retstyle, inner) { return false; }
+        true
+    }
+
+    fn visit_leave_fn(&self, purity: uint, proto: uint,
+                      n_inputs: uint, retstyle: uint) -> bool {
+        if ! self.inner.visit_leave_fn(purity, proto, n_inputs, retstyle) {
+            return false;
+        }
+        true
+    }
+
+    fn visit_enter_enum(&self, n_variants: uint,
+                        get_disr: extern unsafe fn(ptr: *Opaque) -> int,
+                        sz: uint, align: uint)
+                     -> bool {
+        self.align(align);
+        if ! self.inner.visit_enter_enum(n_variants, get_disr, sz, align) {
+            return false;
+        }
+        true
+    }
+
+    fn visit_enter_enum_variant(&self, variant: uint,
+                                disr_val: int,
+                                n_fields: uint,
+                                name: &str) -> bool {
+        if ! self.inner.visit_enter_enum_variant(variant, disr_val,
+                                                 n_fields, name) {
+            return false;
+        }
+        true
+    }
+
+    fn visit_enum_variant_field(&self, i: uint, offset: uint, inner: *TyDesc) -> bool {
+        self.inner.push_ptr();
+        self.bump(offset);
+        if ! self.inner.visit_enum_variant_field(i, offset, inner) { return false; }
+        self.inner.pop_ptr();
+        true
+    }
+
+    fn visit_leave_enum_variant(&self, variant: uint,
+                                disr_val: int,
+                                n_fields: uint,
+                                name: &str) -> bool {
+        if ! self.inner.visit_leave_enum_variant(variant, disr_val,
+                                                 n_fields, name) {
+            return false;
+        }
+        true
+    }
+
+    fn visit_leave_enum(&self, n_variants: uint,
+                        get_disr: extern unsafe fn(ptr: *Opaque) -> int,
+                        sz: uint, align: uint) -> bool {
+        if ! self.inner.visit_leave_enum(n_variants, get_disr, sz, align) {
+            return false;
+        }
+        self.bump(sz);
+        true
+    }
+
+    fn visit_trait(&self) -> bool {
+        self.align_to::<@TyVisitor>();
+        if ! self.inner.visit_trait() { return false; }
+        self.bump_past::<@TyVisitor>();
+        true
+    }
+
+    fn visit_var(&self) -> bool {
+        if ! self.inner.visit_var() { return false; }
+        true
+    }
+
+    fn visit_var_integral(&self) -> bool {
+        if ! self.inner.visit_var_integral() { return false; }
+        true
+    }
+
+    fn visit_param(&self, i: uint) -> bool {
+        if ! self.inner.visit_param(i) { return false; }
+        true
+    }
+
+    fn visit_self(&self) -> bool {
+        self.align_to::<&'static u8>();
+        if ! self.inner.visit_self() { return false; }
+        self.align_to::<&'static u8>();
+        true
+    }
+
+    fn visit_type(&self) -> bool {
+        if ! self.inner.visit_type() { return false; }
+        true
+    }
+
+    fn visit_opaque_box(&self) -> bool {
+        self.align_to::<@u8>();
+        if ! self.inner.visit_opaque_box() { return false; }
+        self.bump_past::<@u8>();
+        true
+    }
+
+    fn visit_constr(&self, inner: *TyDesc) -> bool {
+        if ! self.inner.visit_constr(inner) { return false; }
+        true
+    }
+
+    fn visit_closure_ptr(&self, ck: uint) -> bool {
+        self.align_to::<@fn()>();
+        if ! self.inner.visit_closure_ptr(ck) { return false; }
+        self.bump_past::<@fn()>();
+        true
+    }
+}