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};
  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         // TODO need to check against expected indent
  79         let indent = self.codemap.lookup_char_pos(s.lo).col.0;
  80         match fk {
  81             visit::FkItemFn(ident, ref generics, ref unsafety, ref abi, vis) => {
  82                 let new_fn = self.rewrite_fn(indent,
  83                                              ident,
  84                                              fd,
  85                                              None,
  86                                              generics,
  87                                              unsafety,
  88                                              abi,
  89                                              vis);
  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                 self.changes.push_str_span(s, &new_fn);
 102             }
 103             visit::FkFnBlock(..) => {}
 104         }
 105
 106         self.last_pos = b.span.lo;
 107         self.visit_block(b)
 108     }
 109
 110     fn visit_item(&mut self, item: &'v ast::Item) {
 111         match item.node {
 112             ast::Item_::ItemUse(ref vp) => {
 113                 match vp.node {
 114                     ast::ViewPath_::ViewPathList(ref path, ref path_list) => {
 115                         self.format_missing(item.span.lo);
 116                         let new_str = self.rewrite_use_list(path, path_list, vp.span);
 117                         self.changes.push_str_span(item.span, &new_str);
 118                         self.last_pos = item.span.hi;
 119                     }
 120                     ast::ViewPath_::ViewPathGlob(_) => {
 121                         // FIXME convert to list?
 122                     }
 123                     _ => {}
 124                 }
 125                 visit::walk_item(self, item);
 126             }
 127             ast::Item_::ItemImpl(..) => {
 128                 self.block_indent += TAB_SPACES;
 129                 visit::walk_item(self, item);
 130                 self.block_indent -= TAB_SPACES;
 131             }
 132             _ => {
 133                 visit::walk_item(self, item);
 134             }
 135         }
 136     }
 137
 138     fn visit_mac(&mut self, mac: &'v ast::Mac) {
 139         visit::walk_mac(self, mac)
 140     }
 141
 142     fn visit_mod(&mut self, m: &'v ast::Mod, s: Span, _: ast::NodeId) {
 143         // Only visit inline mods here.
 144         if self.codemap.lookup_char_pos(s.lo).file.name !=
 145            self.codemap.lookup_char_pos(m.inner.lo).file.name {
 146             return;
 147         }
 148         visit::walk_mod(self, m);
 149     }
 150 }
 151
 152 impl<'a> FmtVisitor<'a> {
 153     pub fn from_codemap<'b>(codemap: &'b CodeMap) -> FmtVisitor<'b> {
 154         FmtVisitor {
 155             codemap: codemap,
 156             changes: ChangeSet::from_codemap(codemap),
 157             last_pos: BytePos(0),
 158             block_indent: 0,
 159         }
 160     }
 161
 162     pub fn snippet(&self, span: Span) -> String {
 163         match self.codemap.span_to_snippet(span) {
 164             Ok(s) => s,
 165             Err(_) => {
 166                 println!("Couldn't make snippet for span {:?}->{:?}",
 167                          self.codemap.lookup_char_pos(span.lo),
 168                          self.codemap.lookup_char_pos(span.hi));
 169                 "".to_string()
 170             }
 171         }
 172     }
 173 }