src/librustc_front/util.rs

   1 // Copyright 2015 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 hir;
  12 use hir::*;
  13 use intravisit::{self, Visitor, FnKind};
  14 use syntax::ast_util;
  15 use syntax::ast::{Name, NodeId, DUMMY_NODE_ID};
  16 use syntax::codemap::Span;
  17 use syntax::ptr::P;
  18
  19 pub fn walk_pat<F>(pat: &Pat, mut it: F) -> bool
  20     where F: FnMut(&Pat) -> bool
  21 {
  22     // FIXME(#19596) this is a workaround, but there should be a better way
  23     fn walk_pat_<G>(pat: &Pat, it: &mut G) -> bool
  24         where G: FnMut(&Pat) -> bool
  25     {
  26         if !it(pat) {
  27             return false;
  28         }
  29
  30         match pat.node {
  31             PatKind::Ident(_, _, Some(ref p)) => walk_pat_(&p, it),
  32             PatKind::Struct(_, ref fields, _) => {
  33                 fields.iter().all(|field| walk_pat_(&field.node.pat, it))
  34             }
  35             PatKind::TupleStruct(_, Some(ref s)) | PatKind::Tup(ref s) => {
  36                 s.iter().all(|p| walk_pat_(&p, it))
  37             }
  38             PatKind::Box(ref s) | PatKind::Ref(ref s, _) => {
  39                 walk_pat_(&s, it)
  40             }
  41             PatKind::Vec(ref before, ref slice, ref after) => {
  42                 before.iter().all(|p| walk_pat_(&p, it)) &&
  43                 slice.iter().all(|p| walk_pat_(&p, it)) &&
  44                 after.iter().all(|p| walk_pat_(&p, it))
  45             }
  46             PatKind::Wild |
  47             PatKind::Lit(_) |
  48             PatKind::Range(_, _) |
  49             PatKind::Ident(_, _, _) |
  50             PatKind::TupleStruct(..) |
  51             PatKind::Path(..) |
  52             PatKind::QPath(_, _) => {
  53                 true
  54             }
  55         }
  56     }
  57
  58     walk_pat_(pat, &mut it)
  59 }
  60
  61 pub fn binop_to_string(op: BinOp_) -> &'static str {
  62     match op {
  63         BiAdd => "+",
  64         BiSub => "-",
  65         BiMul => "*",
  66         BiDiv => "/",
  67         BiRem => "%",
  68         BiAnd => "&&",
  69         BiOr => "||",
  70         BiBitXor => "^",
  71         BiBitAnd => "&",
  72         BiBitOr => "|",
  73         BiShl => "<<",
  74         BiShr => ">>",
  75         BiEq => "==",
  76         BiLt => "<",
  77         BiLe => "<=",
  78         BiNe => "!=",
  79         BiGe => ">=",
  80         BiGt => ">",
  81     }
  82 }
  83
  84 pub fn stmt_id(s: &Stmt) -> NodeId {
  85     match s.node {
  86         StmtDecl(_, id) => id,
  87         StmtExpr(_, id) => id,
  88         StmtSemi(_, id) => id,
  89     }
  90 }
  91
  92 pub fn lazy_binop(b: BinOp_) -> bool {
  93     match b {
  94         BiAnd => true,
  95         BiOr => true,
  96         _ => false,
  97     }
  98 }
  99
 100 pub fn is_shift_binop(b: BinOp_) -> bool {
 101     match b {
 102         BiShl => true,
 103         BiShr => true,
 104         _ => false,
 105     }
 106 }
 107
 108 pub fn is_comparison_binop(b: BinOp_) -> bool {
 109     match b {
 110         BiEq | BiLt | BiLe | BiNe | BiGt | BiGe => true,
 111         BiAnd |
 112         BiOr |
 113         BiAdd |
 114         BiSub |
 115         BiMul |
 116         BiDiv |
 117         BiRem |
 118         BiBitXor |
 119         BiBitAnd |
 120         BiBitOr |
 121         BiShl |
 122         BiShr => false,
 123     }
 124 }
 125
 126 /// Returns `true` if the binary operator takes its arguments by value
 127 pub fn is_by_value_binop(b: BinOp_) -> bool {
 128     !is_comparison_binop(b)
 129 }
 130
 131 /// Returns `true` if the unary operator takes its argument by value
 132 pub fn is_by_value_unop(u: UnOp) -> bool {
 133     match u {
 134         UnNeg | UnNot => true,
 135         _ => false,
 136     }
 137 }
 138
 139 pub fn unop_to_string(op: UnOp) -> &'static str {
 140     match op {
 141         UnDeref => "*",
 142         UnNot => "!",
 143         UnNeg => "-",
 144     }
 145 }
 146
 147 pub struct IdVisitor<'a, O: 'a> {
 148     operation: &'a mut O,
 149
 150     // In general, the id visitor visits the contents of an item, but
 151     // not including nested trait/impl items, nor other nested items.
 152     // The base visitor itself always skips nested items, but not
 153     // trait/impl items. This means in particular that if you start by
 154     // visiting a trait or an impl, you should not visit the
 155     // trait/impl items respectively.  This is handled by setting
 156     // `skip_members` to true when `visit_item` is on the stack. This
 157     // way, if the user begins by calling `visit_trait_item`, we will
 158     // visit the trait item, but if they begin with `visit_item`, we
 159     // won't visit the (nested) trait items.
 160     skip_members: bool,
 161 }
 162
 163 impl<'a, O: ast_util::IdVisitingOperation> IdVisitor<'a, O> {
 164     pub fn new(operation: &'a mut O) -> IdVisitor<'a, O> {
 165         IdVisitor { operation: operation, skip_members: false }
 166     }
 167
 168     fn visit_generics_helper(&mut self, generics: &Generics) {
 169         for type_parameter in generics.ty_params.iter() {
 170             self.operation.visit_id(type_parameter.id)
 171         }
 172         for lifetime in &generics.lifetimes {
 173             self.operation.visit_id(lifetime.lifetime.id)
 174         }
 175     }
 176 }
 177
 178 impl<'a, 'v, O: ast_util::IdVisitingOperation> Visitor<'v> for IdVisitor<'a, O> {
 179     fn visit_mod(&mut self, module: &Mod, _: Span, node_id: NodeId) {
 180         self.operation.visit_id(node_id);
 181         intravisit::walk_mod(self, module)
 182     }
 183
 184     fn visit_foreign_item(&mut self, foreign_item: &ForeignItem) {
 185         self.operation.visit_id(foreign_item.id);
 186         intravisit::walk_foreign_item(self, foreign_item)
 187     }
 188
 189     fn visit_item(&mut self, item: &Item) {
 190         assert!(!self.skip_members);
 191         self.skip_members = true;
 192
 193         self.operation.visit_id(item.id);
 194         match item.node {
 195             ItemUse(ref view_path) => {
 196                 match view_path.node {
 197                     ViewPathSimple(_, _) |
 198                     ViewPathGlob(_) => {}
 199                     ViewPathList(_, ref paths) => {
 200                         for path in paths {
 201                             self.operation.visit_id(path.node.id())
 202                         }
 203                     }
 204                 }
 205             }
 206             _ => {}
 207         }
 208         intravisit::walk_item(self, item);
 209
 210         self.skip_members = false;
 211     }
 212
 213     fn visit_local(&mut self, local: &Local) {
 214         self.operation.visit_id(local.id);
 215         intravisit::walk_local(self, local)
 216     }
 217
 218     fn visit_block(&mut self, block: &Block) {
 219         self.operation.visit_id(block.id);
 220         intravisit::walk_block(self, block)
 221     }
 222
 223     fn visit_stmt(&mut self, statement: &Stmt) {
 224         self.operation.visit_id(stmt_id(statement));
 225         intravisit::walk_stmt(self, statement)
 226     }
 227
 228     fn visit_pat(&mut self, pattern: &Pat) {
 229         self.operation.visit_id(pattern.id);
 230         intravisit::walk_pat(self, pattern)
 231     }
 232
 233     fn visit_expr(&mut self, expression: &Expr) {
 234         self.operation.visit_id(expression.id);
 235         intravisit::walk_expr(self, expression)
 236     }
 237
 238     fn visit_ty(&mut self, typ: &Ty) {
 239         self.operation.visit_id(typ.id);
 240         intravisit::walk_ty(self, typ)
 241     }
 242
 243     fn visit_generics(&mut self, generics: &Generics) {
 244         self.visit_generics_helper(generics);
 245         intravisit::walk_generics(self, generics)
 246     }
 247
 248     fn visit_fn(&mut self,
 249                 function_kind: FnKind<'v>,
 250                 function_declaration: &'v FnDecl,
 251                 block: &'v Block,
 252                 span: Span,
 253                 node_id: NodeId) {
 254         self.operation.visit_id(node_id);
 255
 256         match function_kind {
 257             FnKind::ItemFn(_, generics, _, _, _, _) => {
 258                 self.visit_generics_helper(generics)
 259             }
 260             FnKind::Method(_, sig, _) => {
 261                 self.visit_generics_helper(&sig.generics)
 262             }
 263             FnKind::Closure => {}
 264         }
 265
 266         for argument in &function_declaration.inputs {
 267             self.operation.visit_id(argument.id)
 268         }
 269
 270         intravisit::walk_fn(self, function_kind, function_declaration, block, span);
 271     }
 272
 273     fn visit_struct_field(&mut self, struct_field: &StructField) {
 274         self.operation.visit_id(struct_field.node.id);
 275         intravisit::walk_struct_field(self, struct_field)
 276     }
 277
 278     fn visit_variant_data(&mut self,
 279                           struct_def: &VariantData,
 280                           _: Name,
 281                           _: &hir::Generics,
 282                           _: NodeId,
 283                           _: Span) {
 284         self.operation.visit_id(struct_def.id());
 285         intravisit::walk_struct_def(self, struct_def);
 286     }
 287
 288     fn visit_trait_item(&mut self, ti: &hir::TraitItem) {
 289         if !self.skip_members {
 290             self.operation.visit_id(ti.id);
 291             intravisit::walk_trait_item(self, ti);
 292         }
 293     }
 294
 295     fn visit_impl_item(&mut self, ii: &hir::ImplItem) {
 296         if !self.skip_members {
 297             self.operation.visit_id(ii.id);
 298             intravisit::walk_impl_item(self, ii);
 299         }
 300     }
 301
 302     fn visit_lifetime(&mut self, lifetime: &Lifetime) {
 303         self.operation.visit_id(lifetime.id);
 304     }
 305
 306     fn visit_lifetime_def(&mut self, def: &LifetimeDef) {
 307         self.visit_lifetime(&def.lifetime);
 308     }
 309
 310     fn visit_trait_ref(&mut self, trait_ref: &TraitRef) {
 311         self.operation.visit_id(trait_ref.ref_id);
 312         intravisit::walk_trait_ref(self, trait_ref);
 313     }
 314 }
 315
 316 /// Computes the id range for a single fn body, ignoring nested items.
 317 pub fn compute_id_range_for_fn_body(fk: FnKind,
 318                                     decl: &FnDecl,
 319                                     body: &Block,
 320                                     sp: Span,
 321                                     id: NodeId)
 322                                     -> ast_util::IdRange {
 323     let mut visitor = ast_util::IdRangeComputingVisitor { result: ast_util::IdRange::max() };
 324     let mut id_visitor = IdVisitor::new(&mut visitor);
 325     id_visitor.visit_fn(fk, decl, body, sp, id);
 326     id_visitor.operation.result
 327 }
 328
 329 pub fn is_path(e: P<Expr>) -> bool {
 330     match e.node {
 331         ExprPath(..) => true,
 332         _ => false,
 333     }
 334 }
 335
 336 pub fn empty_generics() -> Generics {
 337     Generics {
 338         lifetimes: HirVec::new(),
 339         ty_params: HirVec::new(),
 340         where_clause: WhereClause {
 341             id: DUMMY_NODE_ID,
 342             predicates: HirVec::new(),
 343         },
 344     }
 345 }
 346
 347 // convert a span and an identifier to the corresponding
 348 // 1-segment path
 349 pub fn ident_to_path(s: Span, ident: Ident) -> Path {
 350     hir::Path {
 351         span: s,
 352         global: false,
 353         segments: hir_vec![hir::PathSegment {
 354             identifier: ident,
 355             parameters: hir::AngleBracketedParameters(hir::AngleBracketedParameterData {
 356                 lifetimes: HirVec::new(),
 357                 types: HirVec::new(),
 358                 bindings: HirVec::new(),
 359             }),
 360         }],
 361     }
 362 }