rust/src/libstd/repr.rs
2014-02-04 00:06:08 -08:00

704 lines
21 KiB
Rust

// 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.
/*!
More runtime type reflection
*/
#[allow(missing_doc)];
use cast::transmute;
use char;
use container::Container;
use io;
use iter::Iterator;
use option::{Some, None, Option};
use ptr;
use reflect;
use reflect::{MovePtr, align};
use result::{Ok, Err};
use str::StrSlice;
use to_str::ToStr;
use vec::OwnedVector;
use unstable::intrinsics::{Disr, Opaque, TyDesc, TyVisitor, get_tydesc, visit_tydesc};
use unstable::raw;
macro_rules! if_ok( ($me:expr, $e:expr) => (
match $e {
Ok(()) => {},
Err(e) => { $me.last_err = Some(e); return false; }
}
) )
/// Representations
trait Repr {
fn write_repr(&self, writer: &mut io::Writer) -> io::IoResult<()>;
}
impl Repr for () {
fn write_repr(&self, writer: &mut io::Writer) -> io::IoResult<()> {
writer.write("()".as_bytes())
}
}
impl Repr for bool {
fn write_repr(&self, writer: &mut io::Writer) -> io::IoResult<()> {
let s = if *self { "true" } else { "false" };
writer.write(s.as_bytes())
}
}
impl Repr for int {
fn write_repr(&self, writer: &mut io::Writer) -> io::IoResult<()> {
::int::to_str_bytes(*self, 10u, |bits| {
writer.write(bits)
})
}
}
macro_rules! int_repr(($ty:ident, $suffix:expr) => (impl Repr for $ty {
fn write_repr(&self, writer: &mut io::Writer) -> io::IoResult<()> {
::$ty::to_str_bytes(*self, 10u, |bits| {
writer.write(bits).and_then(|()| {
writer.write(bytes!($suffix))
})
})
}
}))
int_repr!(i8, "i8")
int_repr!(i16, "i16")
int_repr!(i32, "i32")
int_repr!(i64, "i64")
int_repr!(uint, "u")
int_repr!(u8, "u8")
int_repr!(u16, "u16")
int_repr!(u32, "u32")
int_repr!(u64, "u64")
macro_rules! num_repr(($ty:ident, $suffix:expr) => (impl Repr for $ty {
fn write_repr(&self, writer: &mut io::Writer) -> io::IoResult<()> {
let s = self.to_str();
writer.write(s.as_bytes()).and_then(|()| {
writer.write(bytes!($suffix))
})
}
}))
num_repr!(f32, "f32")
num_repr!(f64, "f64")
// New implementation using reflect::MovePtr
enum VariantState {
SearchingFor(Disr),
Matched,
AlreadyFound
}
pub struct ReprVisitor<'a> {
priv ptr: *u8,
priv ptr_stk: ~[*u8],
priv var_stk: ~[VariantState],
priv writer: &'a mut io::Writer,
priv last_err: Option<io::IoError>,
}
pub fn ReprVisitor<'a>(ptr: *u8,
writer: &'a mut io::Writer) -> ReprVisitor<'a> {
ReprVisitor {
ptr: ptr,
ptr_stk: ~[],
var_stk: ~[],
writer: writer,
last_err: None,
}
}
impl<'a> MovePtr for ReprVisitor<'a> {
#[inline]
fn move_ptr(&mut self, adjustment: |*u8| -> *u8) {
self.ptr = adjustment(self.ptr);
}
fn push_ptr(&mut self) {
self.ptr_stk.push(self.ptr);
}
fn pop_ptr(&mut self) {
self.ptr = self.ptr_stk.pop().unwrap();
}
}
impl<'a> ReprVisitor<'a> {
// Various helpers for the TyVisitor impl
#[inline]
pub fn get<T>(&mut self, f: |&mut ReprVisitor, &T| -> bool) -> bool {
unsafe {
f(self, transmute::<*u8,&T>(self.ptr))
}
}
#[inline]
pub fn visit_inner(&mut self, inner: *TyDesc) -> bool {
self.visit_ptr_inner(self.ptr, inner)
}
#[inline]
pub fn visit_ptr_inner(&mut self, ptr: *u8, inner: *TyDesc) -> bool {
unsafe {
// This should call the constructor up above, but due to limiting
// issues we have to recreate it here.
let u = ReprVisitor {
ptr: ptr,
ptr_stk: ~[],
var_stk: ~[],
writer: ::cast::transmute_copy(&self.writer),
last_err: None,
};
let mut v = reflect::MovePtrAdaptor(u);
// Obviously this should not be a thing, but blame #8401 for now
visit_tydesc(inner, &mut v as &mut TyVisitor);
match v.unwrap().last_err {
Some(e) => {
self.last_err = Some(e);
false
}
None => true,
}
}
}
#[inline]
pub fn write<T:Repr>(&mut self) -> bool {
self.get(|this, v:&T| {
if_ok!(this, v.write_repr(this.writer));
true
})
}
pub fn write_escaped_slice(&mut self, slice: &str) -> bool {
if_ok!(self, self.writer.write(['"' as u8]));
for ch in slice.chars() {
if !self.write_escaped_char(ch, true) { return false }
}
if_ok!(self, self.writer.write(['"' as u8]));
true
}
pub fn write_mut_qualifier(&mut self, mtbl: uint) -> bool {
if mtbl == 0 {
if_ok!(self, self.writer.write("mut ".as_bytes()));
} else if mtbl == 1 {
// skip, this is ast::m_imm
} else {
fail!("invalid mutability value");
}
true
}
pub fn write_vec_range(&mut self, ptr: *(), len: uint, inner: *TyDesc) -> bool {
let mut p = ptr as *u8;
let (sz, al) = unsafe { ((*inner).size, (*inner).align) };
if_ok!(self, self.writer.write(['[' as u8]));
let mut first = true;
let mut left = len;
// unit structs have 0 size, and don't loop forever.
let dec = if sz == 0 {1} else {sz};
while left > 0 {
if first {
first = false;
} else {
if_ok!(self, self.writer.write(", ".as_bytes()));
}
self.visit_ptr_inner(p as *u8, inner);
p = align(unsafe { ptr::offset(p, sz as int) as uint }, al) as *u8;
left -= dec;
}
if_ok!(self, self.writer.write([']' as u8]));
true
}
pub fn write_unboxed_vec_repr(&mut self, _: uint, v: &raw::Vec<()>, inner: *TyDesc) -> bool {
self.write_vec_range(ptr::to_unsafe_ptr(&v.data), v.fill, inner)
}
fn write_escaped_char(&mut self, ch: char, is_str: bool) -> bool {
if_ok!(self, match ch {
'\t' => self.writer.write("\\t".as_bytes()),
'\r' => self.writer.write("\\r".as_bytes()),
'\n' => self.writer.write("\\n".as_bytes()),
'\\' => self.writer.write("\\\\".as_bytes()),
'\'' => {
if is_str {
self.writer.write("'".as_bytes())
} else {
self.writer.write("\\'".as_bytes())
}
}
'"' => {
if is_str {
self.writer.write("\\\"".as_bytes())
} else {
self.writer.write("\"".as_bytes())
}
}
'\x20'..'\x7e' => self.writer.write([ch as u8]),
_ => {
char::escape_unicode(ch, |c| {
let _ = self.writer.write([c as u8]);
});
Ok(())
}
});
return true;
}
}
impl<'a> TyVisitor for ReprVisitor<'a> {
fn visit_bot(&mut self) -> bool {
if_ok!(self, self.writer.write("!".as_bytes()));
true
}
fn visit_nil(&mut self) -> bool { self.write::<()>() }
fn visit_bool(&mut self) -> bool { self.write::<bool>() }
fn visit_int(&mut self) -> bool { self.write::<int>() }
fn visit_i8(&mut self) -> bool { self.write::<i8>() }
fn visit_i16(&mut self) -> bool { self.write::<i16>() }
fn visit_i32(&mut self) -> bool { self.write::<i32>() }
fn visit_i64(&mut self) -> bool { self.write::<i64>() }
fn visit_uint(&mut self) -> bool { self.write::<uint>() }
fn visit_u8(&mut self) -> bool { self.write::<u8>() }
fn visit_u16(&mut self) -> bool { self.write::<u16>() }
fn visit_u32(&mut self) -> bool { self.write::<u32>() }
fn visit_u64(&mut self) -> bool { self.write::<u64>() }
fn visit_f32(&mut self) -> bool { self.write::<f32>() }
fn visit_f64(&mut self) -> bool { self.write::<f64>() }
fn visit_char(&mut self) -> bool {
self.get::<char>(|this, &ch| {
if_ok!(this, this.writer.write(['\'' as u8]));
if !this.write_escaped_char(ch, false) { return false }
if_ok!(this, this.writer.write(['\'' as u8]));
true
})
}
fn visit_estr_box(&mut self) -> bool {
true
}
fn visit_estr_uniq(&mut self) -> bool {
self.get::<~str>(|this, s| {
if_ok!(this, this.writer.write(['~' as u8]));
this.write_escaped_slice(*s)
})
}
fn visit_estr_slice(&mut self) -> bool {
self.get::<&str>(|this, s| this.write_escaped_slice(*s))
}
// Type no longer exists, vestigial function.
fn visit_estr_fixed(&mut self, _n: uint, _sz: uint,
_align: uint) -> bool { fail!(); }
fn visit_box(&mut self, mtbl: uint, inner: *TyDesc) -> bool {
if_ok!(self, self.writer.write(['@' as u8]));
self.write_mut_qualifier(mtbl);
self.get::<&raw::Box<()>>(|this, b| {
let p = ptr::to_unsafe_ptr(&b.data) as *u8;
this.visit_ptr_inner(p, inner)
})
}
fn visit_uniq(&mut self, _mtbl: uint, inner: *TyDesc) -> bool {
if_ok!(self, self.writer.write(['~' as u8]));
self.get::<*u8>(|this, b| {
this.visit_ptr_inner(*b, inner)
})
}
fn visit_ptr(&mut self, mtbl: uint, _inner: *TyDesc) -> bool {
self.get::<*u8>(|this, p| {
if_ok!(this, write!(this.writer, "({} as *", *p));
this.write_mut_qualifier(mtbl);
if_ok!(this, this.writer.write("())".as_bytes()));
true
})
}
fn visit_rptr(&mut self, mtbl: uint, inner: *TyDesc) -> bool {
if_ok!(self, self.writer.write(['&' as u8]));
self.write_mut_qualifier(mtbl);
self.get::<*u8>(|this, p| {
this.visit_ptr_inner(*p, inner)
})
}
// Type no longer exists, vestigial function.
fn visit_vec(&mut self, _mtbl: uint, _inner: *TyDesc) -> bool { fail!(); }
fn visit_unboxed_vec(&mut self, mtbl: uint, inner: *TyDesc) -> bool {
self.get::<raw::Vec<()>>(|this, b| {
this.write_unboxed_vec_repr(mtbl, b, inner)
})
}
fn visit_evec_box(&mut self, mtbl: uint, inner: *TyDesc) -> bool {
self.get::<&raw::Box<raw::Vec<()>>>(|this, b| {
if_ok!(this, this.writer.write(['@' as u8]));
this.write_mut_qualifier(mtbl);
this.write_unboxed_vec_repr(mtbl, &b.data, inner)
})
}
fn visit_evec_uniq(&mut self, mtbl: uint, inner: *TyDesc) -> bool {
self.get::<&raw::Vec<()>>(|this, b| {
if_ok!(this, this.writer.write(['~' as u8]));
this.write_unboxed_vec_repr(mtbl, *b, inner)
})
}
fn visit_evec_slice(&mut self, mtbl: uint, inner: *TyDesc) -> bool {
self.get::<raw::Slice<()>>(|this, s| {
if_ok!(this, this.writer.write(['&' as u8]));
this.write_mut_qualifier(mtbl);
let size = unsafe {
if (*inner).size == 0 { 1 } else { (*inner).size }
};
this.write_vec_range(s.data, s.len * size, inner)
})
}
fn visit_evec_fixed(&mut self, n: uint, sz: uint, _align: uint,
_: uint, inner: *TyDesc) -> bool {
let assumed_size = if sz == 0 { n } else { sz };
self.get::<()>(|this, b| {
this.write_vec_range(ptr::to_unsafe_ptr(b), assumed_size, inner)
})
}
fn visit_enter_rec(&mut self, _n_fields: uint,
_sz: uint, _align: uint) -> bool {
if_ok!(self, self.writer.write(['{' as u8]));
true
}
fn visit_rec_field(&mut self, i: uint, name: &str,
mtbl: uint, inner: *TyDesc) -> bool {
if i != 0 {
if_ok!(self, self.writer.write(", ".as_bytes()));
}
self.write_mut_qualifier(mtbl);
if_ok!(self, self.writer.write(name.as_bytes()));
if_ok!(self, self.writer.write(": ".as_bytes()));
self.visit_inner(inner);
true
}
fn visit_leave_rec(&mut self, _n_fields: uint,
_sz: uint, _align: uint) -> bool {
if_ok!(self, self.writer.write(['}' as u8]));
true
}
fn visit_enter_class(&mut self, name: &str, named_fields: bool, n_fields: uint,
_sz: uint, _align: uint) -> bool {
if_ok!(self, self.writer.write(name.as_bytes()));
if n_fields != 0 {
if named_fields {
if_ok!(self, self.writer.write(['{' as u8]));
} else {
if_ok!(self, self.writer.write(['(' as u8]));
}
}
true
}
fn visit_class_field(&mut self, i: uint, name: &str, named: bool,
_mtbl: uint, inner: *TyDesc) -> bool {
if i != 0 {
if_ok!(self, self.writer.write(", ".as_bytes()));
}
if named {
if_ok!(self, self.writer.write(name.as_bytes()));
if_ok!(self, self.writer.write(": ".as_bytes()));
}
self.visit_inner(inner);
true
}
fn visit_leave_class(&mut self, _name: &str, named_fields: bool, n_fields: uint,
_sz: uint, _align: uint) -> bool {
if n_fields != 0 {
if named_fields {
if_ok!(self, self.writer.write(['}' as u8]));
} else {
if_ok!(self, self.writer.write([')' as u8]));
}
}
true
}
fn visit_enter_tup(&mut self, _n_fields: uint,
_sz: uint, _align: uint) -> bool {
if_ok!(self, self.writer.write(['(' as u8]));
true
}
fn visit_tup_field(&mut self, i: uint, inner: *TyDesc) -> bool {
if i != 0 {
if_ok!(self, self.writer.write(", ".as_bytes()));
}
self.visit_inner(inner);
true
}
fn visit_leave_tup(&mut self, _n_fields: uint,
_sz: uint, _align: uint) -> bool {
if _n_fields == 1 {
if_ok!(self, self.writer.write([',' as u8]));
}
if_ok!(self, self.writer.write([')' as u8]));
true
}
fn visit_enter_enum(&mut self,
_n_variants: uint,
get_disr: extern unsafe fn(ptr: *Opaque) -> Disr,
_sz: uint,
_align: uint) -> bool {
let disr = unsafe {
get_disr(transmute(self.ptr))
};
self.var_stk.push(SearchingFor(disr));
true
}
fn visit_enter_enum_variant(&mut self, _variant: uint,
disr_val: Disr,
n_fields: uint,
name: &str) -> bool {
let mut write = false;
match self.var_stk.pop().unwrap() {
SearchingFor(sought) => {
if disr_val == sought {
self.var_stk.push(Matched);
write = true;
} else {
self.var_stk.push(SearchingFor(sought));
}
}
Matched | AlreadyFound => {
self.var_stk.push(AlreadyFound);
}
}
if write {
if_ok!(self, self.writer.write(name.as_bytes()));
if n_fields > 0 {
if_ok!(self, self.writer.write(['(' as u8]));
}
}
true
}
fn visit_enum_variant_field(&mut self,
i: uint,
_offset: uint,
inner: *TyDesc)
-> bool {
match self.var_stk[self.var_stk.len() - 1] {
Matched => {
if i != 0 {
if_ok!(self, self.writer.write(", ".as_bytes()));
}
if ! self.visit_inner(inner) {
return false;
}
}
_ => ()
}
true
}
fn visit_leave_enum_variant(&mut self, _variant: uint,
_disr_val: Disr,
n_fields: uint,
_name: &str) -> bool {
match self.var_stk[self.var_stk.len() - 1] {
Matched => {
if n_fields > 0 {
if_ok!(self, self.writer.write([')' as u8]));
}
}
_ => ()
}
true
}
fn visit_leave_enum(&mut self,
_n_variants: uint,
_get_disr: extern unsafe fn(ptr: *Opaque) -> Disr,
_sz: uint,
_align: uint)
-> bool {
match self.var_stk.pop().unwrap() {
SearchingFor(..) => fail!("enum value matched no variant"),
_ => true
}
}
fn visit_enter_fn(&mut self, _purity: uint, _proto: uint,
_n_inputs: uint, _retstyle: uint) -> bool {
if_ok!(self, self.writer.write("fn(".as_bytes()));
true
}
fn visit_fn_input(&mut self, i: uint, _mode: uint, inner: *TyDesc) -> bool {
if i != 0 {
if_ok!(self, self.writer.write(", ".as_bytes()));
}
let name = unsafe { (*inner).name };
if_ok!(self, self.writer.write(name.as_bytes()));
true
}
fn visit_fn_output(&mut self, _retstyle: uint, variadic: bool,
inner: *TyDesc) -> bool {
if variadic {
if_ok!(self, self.writer.write(", ...".as_bytes()));
}
if_ok!(self, self.writer.write(")".as_bytes()));
let name = unsafe { (*inner).name };
if name != "()" {
if_ok!(self, self.writer.write(" -> ".as_bytes()));
if_ok!(self, self.writer.write(name.as_bytes()));
}
true
}
fn visit_leave_fn(&mut self, _purity: uint, _proto: uint,
_n_inputs: uint, _retstyle: uint) -> bool { true }
fn visit_trait(&mut self, name: &str) -> bool {
if_ok!(self, self.writer.write(name.as_bytes()));
true
}
fn visit_param(&mut self, _i: uint) -> bool { true }
fn visit_self(&mut self) -> bool { true }
fn visit_type(&mut self) -> bool { true }
}
pub fn write_repr<T>(writer: &mut io::Writer, object: &T) -> io::IoResult<()> {
unsafe {
let ptr = ptr::to_unsafe_ptr(object) as *u8;
let tydesc = get_tydesc::<T>();
let u = ReprVisitor(ptr, writer);
let mut v = reflect::MovePtrAdaptor(u);
visit_tydesc(tydesc, &mut v as &mut TyVisitor);
match v.unwrap().last_err {
Some(e) => Err(e),
None => Ok(()),
}
}
}
pub fn repr_to_str<T>(t: &T) -> ~str {
use str;
use io;
let mut result = io::MemWriter::new();
write_repr(&mut result as &mut io::Writer, t).unwrap();
str::from_utf8_owned(result.unwrap()).unwrap()
}
#[cfg(test)]
struct P {a: int, b: f64}
#[test]
fn test_repr() {
use prelude::*;
use str;
use str::Str;
use io::stdio::println;
use util::swap;
use char::is_alphabetic;
fn exact_test<T>(t: &T, e:&str) {
let mut m = io::MemWriter::new();
write_repr(&mut m as &mut io::Writer, t).unwrap();
let s = str::from_utf8_owned(m.unwrap()).unwrap();
assert_eq!(s.as_slice(), e);
}
exact_test(&10, "10");
exact_test(&true, "true");
exact_test(&false, "false");
exact_test(&1.234, "1.234f64");
exact_test(&(&"hello"), "\"hello\"");
exact_test(&(~"he\u10f3llo"), "~\"he\\u10f3llo\"");
exact_test(&(@10), "@10");
exact_test(&(~10), "~10");
exact_test(&(&10), "&10");
let mut x = 10;
exact_test(&(&mut x), "&mut 10");
exact_test(&(0 as *()), "(0x0 as *())");
exact_test(&(0 as *mut ()), "(0x0 as *mut ())");
exact_test(&(1,), "(1,)");
exact_test(&(~["hi", "there"]),
"~[\"hi\", \"there\"]");
exact_test(&(&["hi", "there"]),
"&[\"hi\", \"there\"]");
exact_test(&(P{a:10, b:1.234}),
"repr::P{a: 10, b: 1.234f64}");
exact_test(&(@P{a:10, b:1.234}),
"@repr::P{a: 10, b: 1.234f64}");
exact_test(&(~P{a:10, b:1.234}),
"~repr::P{a: 10, b: 1.234f64}");
exact_test(&(10u8, ~"hello"),
"(10u8, ~\"hello\")");
exact_test(&(10u16, ~"hello"),
"(10u16, ~\"hello\")");
exact_test(&(10u32, ~"hello"),
"(10u32, ~\"hello\")");
exact_test(&(10u64, ~"hello"),
"(10u64, ~\"hello\")");
exact_test(&(&[1, 2]), "&[1, 2]");
exact_test(&(&mut [1, 2]), "&mut [1, 2]");
exact_test(&'\'', "'\\''");
exact_test(&'"', "'\"'");
exact_test(&("'"), "\"'\"");
exact_test(&("\""), "\"\\\"\"");
exact_test(&println, "fn(&str)");
exact_test(&swap::<int>, "fn(&mut int, &mut int)");
exact_test(&is_alphabetic, "fn(char) -> bool");
exact_test(&(~5 as ~ToStr), "~to_str::ToStr:Send");
struct Foo;
exact_test(&(~[Foo, Foo]), "~[repr::test_repr::Foo, repr::test_repr::Foo]");
struct Bar(int, int);
exact_test(&(Bar(2, 2)), "repr::test_repr::Bar(2, 2)");
}