src/visitor.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 syntax::ast;
  12 use syntax::codemap::{CodeMap, Span, BytePos};
  13 use syntax::visit;
  14
  15 use {MAX_WIDTH, TAB_SPACES, SKIP_ANNOTATION};
  16 use changes::ChangeSet;
  17
  18 pub struct FmtVisitor<'a> {
  19     pub codemap: &'a CodeMap,
  20     pub changes: ChangeSet<'a>,
  21     pub last_pos: BytePos,
  22     // TODO RAII util for indenting
  23     pub block_indent: usize,
  24 }
  25
  26 impl<'a, 'v> visit::Visitor<'v> for FmtVisitor<'a> {
  27     fn visit_expr(&mut self, ex: &'v ast::Expr) {
  28         debug!("visit_expr: {:?} {:?}",
  29                self.codemap.lookup_char_pos(ex.span.lo),
  30                self.codemap.lookup_char_pos(ex.span.hi));
  31         self.format_missing(ex.span.lo);
  32         let offset = self.changes.cur_offset_span(ex.span);
  33         let new_str = self.rewrite_expr(ex, MAX_WIDTH - offset, offset);
  34         self.changes.push_str_span(ex.span, &new_str);
  35         self.last_pos = ex.span.hi;
  36     }
  37
  38     fn visit_block(&mut self, b: &'v ast::Block) {
  39         debug!("visit_block: {:?} {:?}",
  40                self.codemap.lookup_char_pos(b.span.lo),
  41                self.codemap.lookup_char_pos(b.span.hi));
  42         self.format_missing(b.span.lo);
  43
  44         self.changes.push_str_span(b.span, "{");
  45         self.last_pos = self.last_pos + BytePos(1);
  46         self.block_indent += TAB_SPACES;
  47
  48         for stmt in &b.stmts {
  49             self.format_missing_with_indent(stmt.span.lo);
  50             self.visit_stmt(&stmt)
  51         }
  52         match b.expr {
  53             Some(ref e) => {
  54                 self.format_missing_with_indent(e.span.lo);
  55                 self.visit_expr(e);
  56             }
  57             None => {}
  58         }
  59
  60         self.block_indent -= TAB_SPACES;
  61         // TODO we should compress any newlines here to just one
  62         self.format_missing_with_indent(b.span.hi - BytePos(1));
  63         self.changes.push_str_span(b.span, "}");
  64         self.last_pos = b.span.hi;
  65     }
  66
  67     // Note that this only gets called for function defintions. Required methods
  68     // on traits do not get handled here.
  69     fn visit_fn(&mut self,
  70                 fk: visit::FnKind<'v>,
  71                 fd: &'v ast::FnDecl,
  72                 b: &'v ast::Block,
  73                 s: Span,
  74                 _: ast::NodeId) {
  75         self.format_missing(s.lo);
  76         self.last_pos = s.lo;
  77
  78         let indent = self.block_indent;
  79         match fk {
  80             visit::FkItemFn(ident, ref generics, ref unsafety, ref abi, vis) => {
  81                 let new_fn = self.rewrite_fn(indent,
  82                                              ident,
  83                                              fd,
  84                                              None,
  85                                              generics,
  86                                              unsafety,
  87                                              abi,
  88                                              vis,
  89                                              b.span);
  90                 self.changes.push_str_span(s, &new_fn);
  91             }
  92             visit::FkMethod(ident, ref sig, vis) => {
  93                 let new_fn = self.rewrite_fn(indent,
  94                                              ident,
  95                                              fd,
  96                                              Some(&sig.explicit_self),
  97                                              &sig.generics,
  98                                              &sig.unsafety,
  99                                              &sig.abi,
 100                                              vis.unwrap_or(ast::Visibility::Inherited),
 101                                              b.span);
 102                 self.changes.push_str_span(s, &new_fn);
 103             }
 104             visit::FkFnBlock(..) => {}
 105         }
 106
 107         self.last_pos = b.span.lo;
 108         self.visit_block(b)
 109     }
 110
 111     fn visit_item(&mut self, item: &'v ast::Item) {
 112         if self.visit_attrs(&item.attrs) {
 113             return;
 114         }
 115
 116         match item.node {
 117             ast::Item_::ItemUse(ref vp) => {
 118                 match vp.node {
 119                     ast::ViewPath_::ViewPathList(ref path, ref path_list) => {
 120                         self.format_missing(item.span.lo);
 121                         let new_str = self.rewrite_use_list(path, path_list, vp.span);
 122                         self.changes.push_str_span(item.span, &new_str);
 123                         self.last_pos = item.span.hi;
 124                     }
 125                     ast::ViewPath_::ViewPathGlob(_) => {
 126                         // FIXME convert to list?
 127                     }
 128                     _ => {}
 129                 }
 130                 visit::walk_item(self, item);
 131             }
 132             ast::Item_::ItemImpl(..) => {
 133                 self.block_indent += TAB_SPACES;
 134                 visit::walk_item(self, item);
 135                 self.block_indent -= TAB_SPACES;
 136             }
 137             ast::Item_::ItemMod(_) => {
 138                 self.block_indent += TAB_SPACES;
 139                 visit::walk_item(self, item);
 140                 self.block_indent -= TAB_SPACES;
 141             }
 142             _ => {
 143                 visit::walk_item(self, item);
 144             }
 145         }
 146     }
 147
 148     fn visit_trait_item(&mut self, ti: &'v ast::TraitItem) {
 149         if self.visit_attrs(&ti.attrs) {
 150             return;
 151         }
 152         visit::walk_trait_item(self, ti)
 153     }
 154
 155     fn visit_impl_item(&mut self, ii: &'v ast::ImplItem) {
 156         if self.visit_attrs(&ii.attrs) {
 157             return;
 158         }
 159         visit::walk_impl_item(self, ii)
 160     }
 161
 162     fn visit_mac(&mut self, mac: &'v ast::Mac) {
 163         visit::walk_mac(self, mac)
 164     }
 165
 166     fn visit_mod(&mut self, m: &'v ast::Mod, s: Span, _: ast::NodeId) {
 167         // Only visit inline mods here.
 168         if self.codemap.lookup_char_pos(s.lo).file.name !=
 169            self.codemap.lookup_char_pos(m.inner.lo).file.name {
 170             return;
 171         }
 172         visit::walk_mod(self, m);
 173     }
 174 }
 175
 176 impl<'a> FmtVisitor<'a> {
 177     pub fn from_codemap<'b>(codemap: &'b CodeMap) -> FmtVisitor<'b> {
 178         FmtVisitor {
 179             codemap: codemap,
 180             changes: ChangeSet::from_codemap(codemap),
 181             last_pos: BytePos(0),
 182             block_indent: 0,
 183         }
 184     }
 185
 186     pub fn snippet(&self, span: Span) -> String {
 187         match self.codemap.span_to_snippet(span) {
 188             Ok(s) => s,
 189             Err(_) => {
 190                 println!("Couldn't make snippet for span {:?}->{:?}",
 191                          self.codemap.lookup_char_pos(span.lo),
 192                          self.codemap.lookup_char_pos(span.hi));
 193                 "".to_string()
 194             }
 195         }
 196     }
 197
 198     // Returns true if we should skip the following item.
 199     fn visit_attrs(&mut self, attrs: &[ast::Attribute]) -> bool {
 200         for a in attrs {
 201             self.format_missing_with_indent(a.span.lo);
 202             if is_skip(&a.node.value) {
 203                 return true;
 204             }
 205
 206             let attr_str = self.snippet(a.span);
 207             self.changes.push_str_span(a.span, &attr_str);
 208             self.last_pos = a.span.hi;
 209         }
 210
 211         false
 212     }
 213 }
 214
 215 fn is_skip(meta_item: &ast::MetaItem) -> bool {
 216     match meta_item.node {
 217         ast::MetaItem_::MetaWord(ref s) => *s == SKIP_ANNOTATION,
 218         _ => false,
 219     }
 220 }