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| 1 | +// Copyright 2012-2017 The Rust Project Developers. See the COPYRIGHT |
| 2 | +// file at the top-level directory of this distribution and at |
| 3 | +// http://rust-lang.org/COPYRIGHT. |
| 4 | +// |
| 5 | +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| 6 | +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| 7 | +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| 8 | +// option. This file may not be copied, modified, or distributed |
| 9 | +// except according to those terms. |
| 10 | + |
| 11 | +use ast::Name; |
| 12 | +use attr; |
| 13 | +use ast::{self, NestedMetaItem}; use ext::base::{ExtCtxt, SyntaxExtension}; |
| 14 | +use codemap; |
| 15 | +use ext::build::AstBuilder; |
| 16 | +use feature_gate; |
| 17 | +use symbol::Symbol; |
| 18 | +use syntax_pos::Span; |
| 19 | + |
| 20 | +pub fn derive_attr_trait<'a>(cx: &mut ExtCtxt, attr: &'a ast::Attribute) |
| 21 | + -> Option<&'a NestedMetaItem> { |
| 22 | + if attr.name() != "derive" { |
| 23 | + return None; |
| 24 | + } |
| 25 | + if attr.value_str().is_some() { |
| 26 | + cx.span_err(attr.span, "unexpected value in `derive`"); |
| 27 | + return None; |
| 28 | + } |
| 29 | + |
| 30 | + let traits = attr.meta_item_list().unwrap_or(&[]); |
| 31 | + |
| 32 | + if traits.is_empty() { |
| 33 | + cx.span_warn(attr.span, "empty trait list in `derive`"); |
| 34 | + return None; |
| 35 | + } |
| 36 | + |
| 37 | + return traits.get(0); |
| 38 | +} |
| 39 | + |
| 40 | +pub fn verify_derive_attrs(cx: &mut ExtCtxt, attrs: &[ast::Attribute]) { |
| 41 | + for attr in attrs { |
| 42 | + if attr.name() != "derive" { |
| 43 | + continue; |
| 44 | + } |
| 45 | + |
| 46 | + if attr.value_str().is_some() { |
| 47 | + cx.span_err(attr.span, "unexpected value in `derive`"); |
| 48 | + } |
| 49 | + |
| 50 | + let traits = attr.meta_item_list().unwrap_or(&[]).to_owned(); |
| 51 | + |
| 52 | + if traits.is_empty() { |
| 53 | + cx.span_warn(attr.span, "empty trait list in `derive`"); |
| 54 | + attr::mark_used(&attr); |
| 55 | + continue; |
| 56 | + } |
| 57 | + for titem in traits { |
| 58 | + if titem.word().is_none() { |
| 59 | + cx.span_err(titem.span, "malformed `derive` entry"); |
| 60 | + } |
| 61 | + } |
| 62 | + } |
| 63 | +} |
| 64 | + |
| 65 | +#[derive(PartialEq, Debug, Clone, Copy)] |
| 66 | +pub enum DeriveType { |
| 67 | + Legacy, |
| 68 | + ProcMacro, |
| 69 | + Builtin |
| 70 | +} |
| 71 | + |
| 72 | +impl DeriveType { |
| 73 | + // Classify a derive trait name by resolving the macro. |
| 74 | + pub fn classify(cx: &mut ExtCtxt, tname: Name) -> DeriveType { |
| 75 | + let legacy_derive_name = Symbol::intern(&format!("derive_{}", tname)); |
| 76 | + |
| 77 | + if let Ok(_) = cx.resolver.resolve_builtin_macro(legacy_derive_name) { |
| 78 | + return DeriveType::Legacy; |
| 79 | + } |
| 80 | + |
| 81 | + match cx.resolver.resolve_builtin_macro(tname) { |
| 82 | + Ok(ext) => match *ext { |
| 83 | + SyntaxExtension::BuiltinDerive(..) => DeriveType::Builtin, |
| 84 | + _ => DeriveType::ProcMacro, |
| 85 | + }, |
| 86 | + Err(_) => DeriveType::ProcMacro, |
| 87 | + } |
| 88 | + } |
| 89 | +} |
| 90 | + |
| 91 | +pub fn get_derive_attr(cx: &mut ExtCtxt, attrs: &mut Vec<ast::Attribute>, |
| 92 | + derive_type: DeriveType) -> Option<ast::Attribute> { |
| 93 | + for i in 0..attrs.len() { |
| 94 | + if attrs[i].name() != "derive" { |
| 95 | + continue; |
| 96 | + } |
| 97 | + |
| 98 | + if attrs[i].value_str().is_some() { |
| 99 | + continue; |
| 100 | + } |
| 101 | + |
| 102 | + let mut traits = attrs[i].meta_item_list().unwrap_or(&[]).to_owned(); |
| 103 | + |
| 104 | + // First, weed out malformed #[derive] |
| 105 | + traits.retain(|titem| titem.word().is_some()); |
| 106 | + |
| 107 | + let mut titem = None; |
| 108 | + |
| 109 | + // See if we can find a matching trait. |
| 110 | + for j in 0..traits.len() { |
| 111 | + let tname = match traits[j].name() { |
| 112 | + Some(tname) => tname, |
| 113 | + _ => continue, |
| 114 | + }; |
| 115 | + |
| 116 | + if DeriveType::classify(cx, tname) == derive_type { |
| 117 | + titem = Some(traits.remove(j)); |
| 118 | + break; |
| 119 | + } |
| 120 | + } |
| 121 | + |
| 122 | + // If we find a trait, remove the trait from the attribute. |
| 123 | + if let Some(titem) = titem { |
| 124 | + if traits.len() == 0 { |
| 125 | + attrs.remove(i); |
| 126 | + } else { |
| 127 | + let derive = Symbol::intern("derive"); |
| 128 | + let mitem = cx.meta_list(titem.span, derive, traits); |
| 129 | + attrs[i] = cx.attribute(titem.span, mitem); |
| 130 | + } |
| 131 | + let derive = Symbol::intern("derive"); |
| 132 | + let mitem = cx.meta_list(titem.span, derive, vec![titem]); |
| 133 | + return Some(cx.attribute(mitem.span, mitem)); |
| 134 | + } |
| 135 | + } |
| 136 | + return None; |
| 137 | +} |
| 138 | + |
| 139 | +fn allow_unstable(cx: &mut ExtCtxt, span: Span, attr_name: &str) -> Span { |
| 140 | + Span { |
| 141 | + expn_id: cx.codemap().record_expansion(codemap::ExpnInfo { |
| 142 | + call_site: span, |
| 143 | + callee: codemap::NameAndSpan { |
| 144 | + format: codemap::MacroAttribute(Symbol::intern(attr_name)), |
| 145 | + span: Some(span), |
| 146 | + allow_internal_unstable: true, |
| 147 | + }, |
| 148 | + }), |
| 149 | + ..span |
| 150 | + } |
| 151 | +} |
| 152 | + |
| 153 | +pub fn add_derived_markers(cx: &mut ExtCtxt, attrs: &mut Vec<ast::Attribute>) { |
| 154 | + if attrs.is_empty() { |
| 155 | + return; |
| 156 | + } |
| 157 | + |
| 158 | + let titems = attrs.iter().filter(|a| { |
| 159 | + a.name() == "derive" |
| 160 | + }).flat_map(|a| { |
| 161 | + a.meta_item_list().unwrap_or(&[]).iter() |
| 162 | + }).filter_map(|titem| { |
| 163 | + titem.name() |
| 164 | + }).collect::<Vec<_>>(); |
| 165 | + |
| 166 | + let span = attrs[0].span; |
| 167 | + |
| 168 | + if !attrs.iter().any(|a| a.name() == "structural_match") && |
| 169 | + titems.iter().any(|t| *t == "PartialEq") && titems.iter().any(|t| *t == "Eq") { |
| 170 | + let structural_match = Symbol::intern("structural_match"); |
| 171 | + let span = allow_unstable(cx, span, "derive(PartialEq, Eq)"); |
| 172 | + let meta = cx.meta_word(span, structural_match); |
| 173 | + attrs.push(cx.attribute(span, meta)); |
| 174 | + } |
| 175 | + |
| 176 | + if !attrs.iter().any(|a| a.name() == "rustc_copy_clone_marker") && |
| 177 | + titems.iter().any(|t| *t == "Copy") && titems.iter().any(|t| *t == "Clone") { |
| 178 | + let structural_match = Symbol::intern("rustc_copy_clone_marker"); |
| 179 | + let span = allow_unstable(cx, span, "derive(Copy, Clone)"); |
| 180 | + let meta = cx.meta_word(span, structural_match); |
| 181 | + attrs.push(cx.attribute(span, meta)); |
| 182 | + } |
| 183 | +} |
| 184 | + |
| 185 | +pub fn find_derive_attr(cx: &mut ExtCtxt, attrs: &mut Vec<ast::Attribute>) |
| 186 | + -> Option<ast::Attribute> { |
| 187 | + verify_derive_attrs(cx, attrs); |
| 188 | + get_derive_attr(cx, attrs, DeriveType::Legacy).and_then(|a| { |
| 189 | + let titem = derive_attr_trait(cx, &a); |
| 190 | + titem.and_then(|titem| { |
| 191 | + let tword = titem.word().unwrap(); |
| 192 | + let tname = tword.name(); |
| 193 | + if !cx.ecfg.enable_custom_derive() { |
| 194 | + feature_gate::emit_feature_err( |
| 195 | + &cx.parse_sess, |
| 196 | + "custom_derive", |
| 197 | + titem.span, |
| 198 | + feature_gate::GateIssue::Language, |
| 199 | + feature_gate::EXPLAIN_CUSTOM_DERIVE |
| 200 | + ); |
| 201 | + None |
| 202 | + } else { |
| 203 | + let name = Symbol::intern(&format!("derive_{}", tname)); |
| 204 | + if !cx.resolver.is_whitelisted_legacy_custom_derive(name) { |
| 205 | + cx.span_warn(titem.span, |
| 206 | + feature_gate::EXPLAIN_DEPR_CUSTOM_DERIVE); |
| 207 | + } |
| 208 | + let mitem = cx.meta_word(titem.span, name); |
| 209 | + Some(cx.attribute(mitem.span, mitem)) |
| 210 | + } |
| 211 | + }) |
| 212 | + }).or_else(|| { |
| 213 | + get_derive_attr(cx, attrs, DeriveType::ProcMacro) |
| 214 | + }).or_else(|| { |
| 215 | + add_derived_markers(cx, attrs); |
| 216 | + get_derive_attr(cx, attrs, DeriveType::Builtin) |
| 217 | + }) |
| 218 | +} |
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