rust/src/libsyntax/attr.rs
2014-07-09 00:06:27 -07:00

530 lines
17 KiB
Rust

// Copyright 2012-2014 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.
// Functions dealing with attributes and meta items
use ast;
use ast::{AttrId, Attribute, Attribute_, MetaItem, MetaWord, MetaNameValue, MetaList};
use codemap::{Span, Spanned, spanned, dummy_spanned};
use codemap::BytePos;
use diagnostic::SpanHandler;
use parse::lexer::comments::{doc_comment_style, strip_doc_comment_decoration};
use parse::token::InternedString;
use parse::token;
use std::collections::HashSet;
use std::collections::BitvSet;
use std::gc::{Gc, GC};
local_data_key!(used_attrs: BitvSet)
pub fn mark_used(attr: &Attribute) {
let mut used = used_attrs.replace(None).unwrap_or_else(|| BitvSet::new());
let AttrId(id) = attr.node.id;
used.insert(id);
used_attrs.replace(Some(used));
}
pub fn is_used(attr: &Attribute) -> bool {
let AttrId(id) = attr.node.id;
used_attrs.get().map_or(false, |used| used.contains(&id))
}
pub trait AttrMetaMethods {
fn check_name(&self, name: &str) -> bool {
name == self.name().get()
}
/// Retrieve the name of the meta item, e.g. foo in #[foo],
/// #[foo="bar"] and #[foo(bar)]
fn name(&self) -> InternedString;
/// Gets the string value if self is a MetaNameValue variant
/// containing a string, otherwise None.
fn value_str(&self) -> Option<InternedString>;
/// Gets a list of inner meta items from a list MetaItem type.
fn meta_item_list<'a>(&'a self) -> Option<&'a [Gc<MetaItem>]>;
}
impl AttrMetaMethods for Attribute {
fn check_name(&self, name: &str) -> bool {
let matches = name == self.name().get();
if matches {
mark_used(self);
}
matches
}
fn name(&self) -> InternedString { self.meta().name() }
fn value_str(&self) -> Option<InternedString> {
self.meta().value_str()
}
fn meta_item_list<'a>(&'a self) -> Option<&'a [Gc<MetaItem>]> {
self.node.value.meta_item_list()
}
}
impl AttrMetaMethods for MetaItem {
fn name(&self) -> InternedString {
match self.node {
MetaWord(ref n) => (*n).clone(),
MetaNameValue(ref n, _) => (*n).clone(),
MetaList(ref n, _) => (*n).clone(),
}
}
fn value_str(&self) -> Option<InternedString> {
match self.node {
MetaNameValue(_, ref v) => {
match v.node {
ast::LitStr(ref s, _) => Some((*s).clone()),
_ => None,
}
},
_ => None
}
}
fn meta_item_list<'a>(&'a self) -> Option<&'a [Gc<MetaItem>]> {
match self.node {
MetaList(_, ref l) => Some(l.as_slice()),
_ => None
}
}
}
// Annoying, but required to get test_cfg to work
impl AttrMetaMethods for Gc<MetaItem> {
fn name(&self) -> InternedString { (**self).name() }
fn value_str(&self) -> Option<InternedString> { (**self).value_str() }
fn meta_item_list<'a>(&'a self) -> Option<&'a [Gc<MetaItem>]> {
(**self).meta_item_list()
}
}
pub trait AttributeMethods {
fn meta(&self) -> Gc<MetaItem>;
fn desugar_doc(&self) -> Attribute;
}
impl AttributeMethods for Attribute {
/// Extract the MetaItem from inside this Attribute.
fn meta(&self) -> Gc<MetaItem> {
self.node.value
}
/// Convert self to a normal #[doc="foo"] comment, if it is a
/// comment like `///` or `/** */`. (Returns self unchanged for
/// non-sugared doc attributes.)
fn desugar_doc(&self) -> Attribute {
if self.node.is_sugared_doc {
let comment = self.value_str().unwrap();
let meta = mk_name_value_item_str(
InternedString::new("doc"),
token::intern_and_get_ident(strip_doc_comment_decoration(
comment.get()).as_slice()));
if self.node.style == ast::AttrOuter {
mk_attr_outer(self.node.id, meta)
} else {
mk_attr_inner(self.node.id, meta)
}
} else {
*self
}
}
}
/* Constructors */
pub fn mk_name_value_item_str(name: InternedString, value: InternedString)
-> Gc<MetaItem> {
let value_lit = dummy_spanned(ast::LitStr(value, ast::CookedStr));
mk_name_value_item(name, value_lit)
}
pub fn mk_name_value_item(name: InternedString, value: ast::Lit)
-> Gc<MetaItem> {
box(GC) dummy_spanned(MetaNameValue(name, value))
}
pub fn mk_list_item(name: InternedString,
items: Vec<Gc<MetaItem>>) -> Gc<MetaItem> {
box(GC) dummy_spanned(MetaList(name, items))
}
pub fn mk_word_item(name: InternedString) -> Gc<MetaItem> {
box(GC) dummy_spanned(MetaWord(name))
}
local_data_key!(next_attr_id: uint)
pub fn mk_attr_id() -> AttrId {
let id = next_attr_id.replace(None).unwrap_or(0);
next_attr_id.replace(Some(id + 1));
AttrId(id)
}
/// Returns an inner attribute with the given value.
pub fn mk_attr_inner(id: AttrId, item: Gc<MetaItem>) -> Attribute {
dummy_spanned(Attribute_ {
id: id,
style: ast::AttrInner,
value: item,
is_sugared_doc: false,
})
}
/// Returns an outer attribute with the given value.
pub fn mk_attr_outer(id: AttrId, item: Gc<MetaItem>) -> Attribute {
dummy_spanned(Attribute_ {
id: id,
style: ast::AttrOuter,
value: item,
is_sugared_doc: false,
})
}
pub fn mk_sugared_doc_attr(id: AttrId, text: InternedString, lo: BytePos,
hi: BytePos)
-> Attribute {
let style = doc_comment_style(text.get());
let lit = spanned(lo, hi, ast::LitStr(text, ast::CookedStr));
let attr = Attribute_ {
id: id,
style: style,
value: box(GC) spanned(lo, hi, MetaNameValue(InternedString::new("doc"),
lit)),
is_sugared_doc: true
};
spanned(lo, hi, attr)
}
/* Searching */
/// Check if `needle` occurs in `haystack` by a structural
/// comparison. This is slightly subtle, and relies on ignoring the
/// span included in the `==` comparison a plain MetaItem.
pub fn contains(haystack: &[Gc<ast::MetaItem>],
needle: Gc<ast::MetaItem>) -> bool {
debug!("attr::contains (name={})", needle.name());
haystack.iter().any(|item| {
debug!(" testing: {}", item.name());
item.node == needle.node
})
}
pub fn contains_name<AM: AttrMetaMethods>(metas: &[AM], name: &str) -> bool {
debug!("attr::contains_name (name={})", name);
metas.iter().any(|item| {
debug!(" testing: {}", item.name());
item.check_name(name)
})
}
pub fn first_attr_value_str_by_name(attrs: &[Attribute], name: &str)
-> Option<InternedString> {
attrs.iter()
.find(|at| at.check_name(name))
.and_then(|at| at.value_str())
}
pub fn last_meta_item_value_str_by_name(items: &[Gc<MetaItem>], name: &str)
-> Option<InternedString> {
items.iter()
.rev()
.find(|mi| mi.check_name(name))
.and_then(|i| i.value_str())
}
/* Higher-level applications */
pub fn sort_meta_items(items: &[Gc<MetaItem>]) -> Vec<Gc<MetaItem>> {
// This is sort of stupid here, but we need to sort by
// human-readable strings.
let mut v = items.iter()
.map(|&mi| (mi.name(), mi))
.collect::<Vec<(InternedString, Gc<MetaItem>)> >();
v.sort_by(|&(ref a, _), &(ref b, _)| a.cmp(b));
// There doesn't seem to be a more optimal way to do this
v.move_iter().map(|(_, m)| {
match m.node {
MetaList(ref n, ref mis) => {
box(GC) Spanned {
node: MetaList((*n).clone(),
sort_meta_items(mis.as_slice())),
.. /*bad*/ (*m).clone()
}
}
_ => m
}
}).collect()
}
pub fn find_crate_name(attrs: &[Attribute]) -> Option<InternedString> {
first_attr_value_str_by_name(attrs, "crate_name")
}
#[deriving(PartialEq)]
pub enum InlineAttr {
InlineNone,
InlineHint,
InlineAlways,
InlineNever,
}
/// True if something like #[inline] is found in the list of attrs.
pub fn find_inline_attr(attrs: &[Attribute]) -> InlineAttr {
// FIXME (#2809)---validate the usage of #[inline] and #[inline]
attrs.iter().fold(InlineNone, |ia,attr| {
match attr.node.value.node {
MetaWord(ref n) if n.equiv(&("inline")) => {
mark_used(attr);
InlineHint
}
MetaList(ref n, ref items) if n.equiv(&("inline")) => {
mark_used(attr);
if contains_name(items.as_slice(), "always") {
InlineAlways
} else if contains_name(items.as_slice(), "never") {
InlineNever
} else {
InlineHint
}
}
_ => ia
}
})
}
/// Tests if any `cfg(...)` meta items in `metas` match `cfg`. e.g.
///
/// test_cfg(`[foo="a", bar]`, `[cfg(foo), cfg(bar)]`) == true
/// test_cfg(`[foo="a", bar]`, `[cfg(not(bar))]`) == false
/// test_cfg(`[foo="a", bar]`, `[cfg(bar, foo="a")]`) == true
/// test_cfg(`[foo="a", bar]`, `[cfg(bar, foo="b")]`) == false
pub fn test_cfg<AM: AttrMetaMethods, It: Iterator<AM>>
(cfg: &[Gc<MetaItem>], mut metas: It) -> bool {
// having no #[cfg(...)] attributes counts as matching.
let mut no_cfgs = true;
// this would be much nicer as a chain of iterator adaptors, but
// this doesn't work.
let some_cfg_matches = metas.fold(false, |matches, mi| {
debug!("testing name: {}", mi.name());
let this_matches = if mi.check_name("cfg") { // it is a #[cfg()] attribute
debug!("is cfg");
no_cfgs = false;
// only #[cfg(...)] ones are understood.
match mi.meta_item_list() {
Some(cfg_meta) => {
debug!("is cfg(...)");
cfg_meta.iter().all(|cfg_mi| {
debug!("cfg({}[...])", cfg_mi.name());
match cfg_mi.node {
ast::MetaList(ref s, ref not_cfgs)
if s.equiv(&("not")) => {
debug!("not!");
// inside #[cfg(not(...))], so these need to all
// not match.
!not_cfgs.iter().all(|mi| {
debug!("cfg(not({}[...]))", mi.name());
contains(cfg, *mi)
})
}
_ => contains(cfg, *cfg_mi)
}
})
}
None => false
}
} else {
false
};
matches || this_matches
});
debug!("test_cfg (no_cfgs={}, some_cfg_matches={})", no_cfgs, some_cfg_matches);
no_cfgs || some_cfg_matches
}
/// Represents the #[deprecated="foo"] and friends attributes.
#[deriving(Encodable,Decodable,Clone,Show)]
pub struct Stability {
pub level: StabilityLevel,
pub text: Option<InternedString>
}
/// The available stability levels.
#[deriving(Encodable,Decodable,PartialEq,PartialOrd,Clone,Show)]
pub enum StabilityLevel {
Deprecated,
Experimental,
Unstable,
Stable,
Frozen,
Locked
}
pub fn find_stability_generic<'a,
AM: AttrMetaMethods,
I: Iterator<&'a AM>>
(mut attrs: I)
-> Option<(Stability, &'a AM)> {
for attr in attrs {
let level = match attr.name().get() {
"deprecated" => Deprecated,
"experimental" => Experimental,
"unstable" => Unstable,
"stable" => Stable,
"frozen" => Frozen,
"locked" => Locked,
_ => continue // not a stability level
};
return Some((Stability {
level: level,
text: attr.value_str()
}, attr));
}
None
}
/// Find the first stability attribute. `None` if none exists.
pub fn find_stability(attrs: &[Attribute]) -> Option<Stability> {
find_stability_generic(attrs.iter()).map(|(s, attr)| {
mark_used(attr);
s
})
}
pub fn require_unique_names(diagnostic: &SpanHandler, metas: &[Gc<MetaItem>]) {
let mut set = HashSet::new();
for meta in metas.iter() {
let name = meta.name();
if !set.insert(name.clone()) {
diagnostic.span_fatal(meta.span,
format!("duplicate meta item `{}`",
name).as_slice());
}
}
}
/// Fold this over attributes to parse #[repr(...)] forms.
///
/// Valid repr contents: any of the primitive integral type names (see
/// `int_type_of_word`, below) to specify the discriminant type; and `C`, to use
/// the same discriminant size that the corresponding C enum would. These are
/// not allowed on univariant or zero-variant enums, which have no discriminant.
///
/// If a discriminant type is so specified, then the discriminant will be
/// present (before fields, if any) with that type; reprensentation
/// optimizations which would remove it will not be done.
pub fn find_repr_attr(diagnostic: &SpanHandler, attr: &Attribute, acc: ReprAttr)
-> ReprAttr {
let mut acc = acc;
match attr.node.value.node {
ast::MetaList(ref s, ref items) if s.equiv(&("repr")) => {
mark_used(attr);
for item in items.iter() {
match item.node {
ast::MetaWord(ref word) => {
let hint = match word.get() {
// Can't use "extern" because it's not a lexical identifier.
"C" => ReprExtern,
_ => match int_type_of_word(word.get()) {
Some(ity) => ReprInt(item.span, ity),
None => {
// Not a word we recognize
diagnostic.span_err(item.span,
"unrecognized representation hint");
ReprAny
}
}
};
if hint != ReprAny {
if acc == ReprAny {
acc = hint;
} else if acc != hint {
diagnostic.span_warn(item.span,
"conflicting representation hint ignored")
}
}
}
// Not a word:
_ => diagnostic.span_err(item.span, "unrecognized representation hint")
}
}
}
// Not a "repr" hint: ignore.
_ => { }
}
acc
}
fn int_type_of_word(s: &str) -> Option<IntType> {
match s {
"i8" => Some(SignedInt(ast::TyI8)),
"u8" => Some(UnsignedInt(ast::TyU8)),
"i16" => Some(SignedInt(ast::TyI16)),
"u16" => Some(UnsignedInt(ast::TyU16)),
"i32" => Some(SignedInt(ast::TyI32)),
"u32" => Some(UnsignedInt(ast::TyU32)),
"i64" => Some(SignedInt(ast::TyI64)),
"u64" => Some(UnsignedInt(ast::TyU64)),
"int" => Some(SignedInt(ast::TyI)),
"uint" => Some(UnsignedInt(ast::TyU)),
_ => None
}
}
#[deriving(PartialEq, Show)]
pub enum ReprAttr {
ReprAny,
ReprInt(Span, IntType),
ReprExtern
}
impl ReprAttr {
pub fn is_ffi_safe(&self) -> bool {
match *self {
ReprAny => false,
ReprInt(_sp, ity) => ity.is_ffi_safe(),
ReprExtern => true
}
}
}
#[deriving(PartialEq, Show)]
pub enum IntType {
SignedInt(ast::IntTy),
UnsignedInt(ast::UintTy)
}
impl IntType {
#[inline]
pub fn is_signed(self) -> bool {
match self {
SignedInt(..) => true,
UnsignedInt(..) => false
}
}
fn is_ffi_safe(self) -> bool {
match self {
SignedInt(ast::TyI8) | UnsignedInt(ast::TyU8) |
SignedInt(ast::TyI16) | UnsignedInt(ast::TyU16) |
SignedInt(ast::TyI32) | UnsignedInt(ast::TyU32) |
SignedInt(ast::TyI64) | UnsignedInt(ast::TyU64) => true,
_ => false
}
}
}