]> git.lizzy.rs Git - rust.git/blobdiff - src/imports.rs
Change `print_diff` to output the correct line number.
[rust.git] / src / imports.rs
index 48b6af7fd4624959168ee809ae0cc72c0a441287..3ca063a58e72655118401627bac52e3aff59f8ff 100644 (file)
 
 use config::lists::*;
 use syntax::ast::{self, UseTreeKind};
-use syntax::codemap::{BytePos, Span};
+use syntax::source_map::{self, BytePos, Span, DUMMY_SP};
 
-use codemap::SpanUtils;
-use config::IndentStyle;
+use comment::combine_strs_with_missing_comments;
+use config::{Edition, IndentStyle};
 use lists::{definitive_tactic, itemize_list, write_list, ListFormatting, ListItem, Separator};
 use rewrite::{Rewrite, RewriteContext};
 use shape::Shape;
+use source_map::SpanUtils;
 use spanned::Spanned;
-use utils::mk_sp;
+use utils::{is_same_visibility, mk_sp, rewrite_ident};
 use visitor::FmtVisitor;
 
 use std::borrow::Cow;
+use std::fmt;
 
 /// Returns a name imported by a `use` declaration. e.g. returns `Ordering`
 /// for `std::cmp::Ordering` and `self` for `std::cmp::self`.
@@ -33,7 +35,7 @@ pub fn path_to_imported_ident(path: &ast::Path) -> ast::Ident {
 
 impl<'a> FmtVisitor<'a> {
     pub fn format_import(&mut self, item: &ast::Item, tree: &ast::UseTree) {
-        let span = item.span;
+        let span = item.span();
         let shape = self.shape();
         let rw = UseTree::from_ast(
             &self.get_context(),
@@ -89,7 +91,7 @@ pub fn format_import(&mut self, item: &ast::Item, tree: &ast::UseTree) {
 // sorting.
 
 // FIXME we do a lot of allocation to make our own representation.
-#[derive(Debug, Clone, Eq, PartialEq)]
+#[derive(Clone, Eq, PartialEq)]
 pub enum UseSegment {
     Ident(String, Option<String>),
     Slf(Option<String>),
@@ -98,12 +100,12 @@ pub enum UseSegment {
     List(Vec<UseTree>),
 }
 
-#[derive(Debug, Clone)]
+#[derive(Clone)]
 pub struct UseTree {
     pub path: Vec<UseSegment>,
     pub span: Span,
     // Comment information within nested use tree.
-    list_item: Option<ListItem>,
+    pub list_item: Option<ListItem>,
     // Additional fields for top level use items.
     // Should we have another struct for top-level use items rather than reusing this?
     visibility: Option<ast::Visibility>,
@@ -117,6 +119,17 @@ fn eq(&self, other: &UseTree) -> bool {
 }
 impl Eq for UseTree {}
 
+impl Spanned for UseTree {
+    fn span(&self) -> Span {
+        let lo = if let Some(ref attrs) = self.attrs {
+            attrs.iter().next().map_or(self.span.lo(), |a| a.span.lo())
+        } else {
+            self.span.lo()
+        };
+        mk_sp(lo, self.span.hi())
+    }
+}
+
 impl UseSegment {
     // Clone a version of self with any top-level alias removed.
     fn remove_alias(&self) -> UseSegment {
@@ -128,44 +141,137 @@ fn remove_alias(&self) -> UseSegment {
         }
     }
 
-    fn from_path_segment(path_seg: &ast::PathSegment) -> Option<UseSegment> {
-        let name = path_seg.ident.name.as_str();
-        if name == "{{root}}" {
+    fn from_path_segment(
+        context: &RewriteContext,
+        path_seg: &ast::PathSegment,
+        modsep: bool,
+    ) -> Option<UseSegment> {
+        let name = rewrite_ident(context, path_seg.ident);
+        if name.is_empty() || name == "{{root}}" {
             return None;
         }
-        Some(if name == "self" {
-            UseSegment::Slf(None)
-        } else if name == "super" {
-            UseSegment::Super(None)
-        } else {
-            UseSegment::Ident((*name).to_owned(), None)
+        Some(match name {
+            "self" => UseSegment::Slf(None),
+            "super" => UseSegment::Super(None),
+            _ => {
+                let mod_sep = if modsep { "::" } else { "" };
+                UseSegment::Ident(format!("{}{}", mod_sep, name), None)
+            }
         })
     }
 }
 
-impl UseTree {
-    // Rewrite use tree with `use ` and a trailing `;`.
-    pub fn rewrite_top_level(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
-        let mut result = String::with_capacity(256);
-        if let Some(ref attrs) = self.attrs {
-            result.push_str(&attrs.rewrite(context, shape)?);
-            if !result.is_empty() {
-                result.push_str(&shape.indent.to_string_with_newline(context.config));
+pub fn merge_use_trees(use_trees: Vec<UseTree>) -> Vec<UseTree> {
+    let mut result = Vec::with_capacity(use_trees.len());
+    for use_tree in use_trees {
+        if use_tree.has_comment() || use_tree.attrs.is_some() {
+            result.push(use_tree);
+            continue;
+        }
+
+        for flattened in use_tree.flatten() {
+            merge_use_trees_inner(&mut result, flattened);
+        }
+    }
+    result
+}
+
+fn merge_use_trees_inner(trees: &mut Vec<UseTree>, use_tree: UseTree) {
+    for tree in trees.iter_mut() {
+        if tree.share_prefix(&use_tree) {
+            tree.merge(&use_tree);
+            return;
+        }
+    }
+
+    trees.push(use_tree);
+}
+
+impl fmt::Debug for UseTree {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(self, f)
+    }
+}
+
+impl fmt::Debug for UseSegment {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(self, f)
+    }
+}
+
+impl fmt::Display for UseSegment {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            UseSegment::Glob => write!(f, "*"),
+            UseSegment::Ident(ref s, _) => write!(f, "{}", s),
+            UseSegment::Slf(..) => write!(f, "self"),
+            UseSegment::Super(..) => write!(f, "super"),
+            UseSegment::List(ref list) => {
+                write!(f, "{{")?;
+                for (i, item) in list.iter().enumerate() {
+                    let is_last = i == list.len() - 1;
+                    write!(f, "{}", item)?;
+                    if !is_last {
+                        write!(f, ", ")?;
+                    }
+                }
+                write!(f, "}}")
+            }
+        }
+    }
+}
+impl fmt::Display for UseTree {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        for (i, segment) in self.path.iter().enumerate() {
+            let is_last = i == self.path.len() - 1;
+            write!(f, "{}", segment)?;
+            if !is_last {
+                write!(f, "::")?;
             }
         }
+        write!(f, "")
+    }
+}
 
-        let vis = self.visibility
-            .as_ref()
-            .map_or(Cow::from(""), |vis| ::utils::format_visibility(&vis));
-        result.push_str(&self.rewrite(context, shape.offset_left(vis.len())?)
+impl UseTree {
+    // Rewrite use tree with `use ` and a trailing `;`.
+    pub fn rewrite_top_level(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
+        let vis = self.visibility.as_ref().map_or(Cow::from(""), |vis| {
+            ::utils::format_visibility(context, &vis)
+        });
+        let use_str = self
+            .rewrite(context, shape.offset_left(vis.len())?)
             .map(|s| {
                 if s.is_empty() {
                     s.to_owned()
                 } else {
                     format!("{}use {};", vis, s)
                 }
-            })?);
-        Some(result)
+            })?;
+        if let Some(ref attrs) = self.attrs {
+            let attr_str = attrs.rewrite(context, shape)?;
+            let lo = attrs.last().as_ref()?.span().hi();
+            let hi = self.span.lo();
+            let span = mk_sp(lo, hi);
+            combine_strs_with_missing_comments(context, &attr_str, &use_str, span, shape, false)
+        } else {
+            Some(use_str)
+        }
+    }
+
+    // FIXME: Use correct span?
+    // The given span is essentially incorrect, since we are reconstructing
+    // use statements. This should not be a problem, though, since we have
+    // already tried to extract comment and observed that there are no comment
+    // around the given use item, and the span will not be used afterward.
+    fn from_path(path: Vec<UseSegment>, span: Span) -> UseTree {
+        UseTree {
+            path,
+            span,
+            list_item: None,
+            visibility: None,
+            attrs: None,
+        }
     }
 
     pub fn from_ast_with_normalization(
@@ -179,7 +285,7 @@ pub fn from_ast_with_normalization(
                     use_tree,
                     None,
                     Some(item.vis.clone()),
-                    Some(item.span().lo()),
+                    Some(item.span.lo()),
                     if item.attrs.is_empty() {
                         None
                     } else {
@@ -211,8 +317,13 @@ fn from_ast(
             visibility,
             attrs,
         };
+
+        let leading_modsep = context.config.edition() == Edition::Edition2018
+            && a.prefix.to_string().len() > 2
+            && a.prefix.to_string().starts_with("::");
+
         for p in &a.prefix.segments {
-            if let Some(use_segment) = UseSegment::from_path_segment(p) {
+            if let Some(use_segment) = UseSegment::from_path_segment(context, p, leading_modsep) {
                 result.path.push(use_segment);
             }
         }
@@ -240,26 +351,25 @@ fn from_ast(
                         .zip(items.into_iter())
                         .map(|(t, list_item)| {
                             Self::from_ast(context, &t.0, Some(list_item), None, None, None)
-                        })
-                        .collect(),
+                        }).collect(),
                 ));
             }
-            UseTreeKind::Simple(ref rename) => {
-                let mut name = (*path_to_imported_ident(&a.prefix).name.as_str()).to_owned();
+            UseTreeKind::Simple(ref rename, ..) => {
+                let name = rewrite_ident(context, path_to_imported_ident(&a.prefix)).to_owned();
                 let alias = rename.and_then(|ident| {
-                    if ident == path_to_imported_ident(&a.prefix) {
+                    if ident.name == "_" {
+                        // for impl-only-use
+                        Some("_".to_owned())
+                    } else if ident == path_to_imported_ident(&a.prefix) {
                         None
                     } else {
-                        Some(ident.to_string())
+                        Some(rewrite_ident(context, ident).to_owned())
                     }
                 });
-
-                let segment = if &name == "self" {
-                    UseSegment::Slf(alias)
-                } else if &name == "super" {
-                    UseSegment::Super(alias)
-                } else {
-                    UseSegment::Ident(name, alias)
+                let segment = match name.as_ref() {
+                    "self" => UseSegment::Slf(alias),
+                    "super" => UseSegment::Super(alias),
+                    _ => UseSegment::Ident(name, alias),
                 };
 
                 // `name` is already in result.
@@ -293,7 +403,7 @@ pub fn normalize(mut self) -> UseTree {
 
         // Normalise foo::self -> foo.
         if let UseSegment::Slf(None) = last {
-            if self.path.len() > 0 {
+            if !self.path.is_empty() {
                 return self;
             }
         }
@@ -348,7 +458,8 @@ pub fn normalize(mut self) -> UseTree {
 
         // Recursively normalize elements of a list use (including sorting the list).
         if let UseSegment::List(list) = last {
-            let mut list = list.into_iter()
+            let mut list = list
+                .into_iter()
                 .map(|ut| ut.normalize())
                 .collect::<Vec<_>>();
             list.sort();
@@ -358,6 +469,124 @@ pub fn normalize(mut self) -> UseTree {
         self.path.push(last);
         self
     }
+
+    fn has_comment(&self) -> bool {
+        self.list_item.as_ref().map_or(false, ListItem::has_comment)
+    }
+
+    fn same_visibility(&self, other: &UseTree) -> bool {
+        match (&self.visibility, &other.visibility) {
+            (
+                Some(source_map::Spanned {
+                    node: ast::VisibilityKind::Inherited,
+                    ..
+                }),
+                None,
+            )
+            | (
+                None,
+                Some(source_map::Spanned {
+                    node: ast::VisibilityKind::Inherited,
+                    ..
+                }),
+            )
+            | (None, None) => true,
+            (Some(ref a), Some(ref b)) => is_same_visibility(a, b),
+            _ => false,
+        }
+    }
+
+    fn share_prefix(&self, other: &UseTree) -> bool {
+        if self.path.is_empty()
+            || other.path.is_empty()
+            || self.attrs.is_some()
+            || !self.same_visibility(other)
+        {
+            false
+        } else {
+            self.path[0] == other.path[0]
+        }
+    }
+
+    fn flatten(self) -> Vec<UseTree> {
+        if self.path.is_empty() {
+            return vec![self];
+        }
+        match self.path.clone().last().unwrap() {
+            UseSegment::List(list) => {
+                let prefix = &self.path[..self.path.len() - 1];
+                let mut result = vec![];
+                for nested_use_tree in list {
+                    for flattend in &mut nested_use_tree.clone().flatten() {
+                        let mut new_path = prefix.to_vec();
+                        new_path.append(&mut flattend.path);
+                        result.push(UseTree {
+                            path: new_path,
+                            span: self.span,
+                            list_item: None,
+                            visibility: self.visibility.clone(),
+                            attrs: None,
+                        });
+                    }
+                }
+
+                result
+            }
+            _ => vec![self],
+        }
+    }
+
+    fn merge(&mut self, other: &UseTree) {
+        let mut new_path = vec![];
+        for (a, b) in self
+            .path
+            .clone()
+            .iter_mut()
+            .zip(other.path.clone().into_iter())
+        {
+            if *a == b {
+                new_path.push(b);
+            } else {
+                break;
+            }
+        }
+        if let Some(merged) = merge_rest(&self.path, &other.path, new_path.len()) {
+            new_path.push(merged);
+            self.span = self.span.to(other.span);
+        }
+        self.path = new_path;
+    }
+}
+
+fn merge_rest(a: &[UseSegment], b: &[UseSegment], len: usize) -> Option<UseSegment> {
+    let a_rest = &a[len..];
+    let b_rest = &b[len..];
+    if a_rest.is_empty() && b_rest.is_empty() {
+        return None;
+    }
+    if a_rest.is_empty() {
+        return Some(UseSegment::List(vec![
+            UseTree::from_path(vec![UseSegment::Slf(None)], DUMMY_SP),
+            UseTree::from_path(b_rest.to_vec(), DUMMY_SP),
+        ]));
+    }
+    if b_rest.is_empty() {
+        return Some(UseSegment::List(vec![
+            UseTree::from_path(vec![UseSegment::Slf(None)], DUMMY_SP),
+            UseTree::from_path(a_rest.to_vec(), DUMMY_SP),
+        ]));
+    }
+    if let UseSegment::List(mut list) = a_rest[0].clone() {
+        merge_use_trees_inner(&mut list, UseTree::from_path(b_rest.to_vec(), DUMMY_SP));
+        list.sort();
+        return Some(UseSegment::List(list.clone()));
+    }
+    let mut list = vec![
+        UseTree::from_path(a_rest.to_vec(), DUMMY_SP),
+        UseTree::from_path(b_rest.to_vec(), DUMMY_SP),
+    ];
+    list.sort();
+    Some(UseSegment::List(list))
 }
 
 impl PartialOrd for UseSegment {
@@ -375,7 +604,8 @@ fn cmp(&self, other: &UseSegment) -> Ordering {
         use self::UseSegment::*;
 
         fn is_upper_snake_case(s: &str) -> bool {
-            s.chars().all(|c| c.is_uppercase() || c == '_')
+            s.chars()
+                .all(|c| c.is_uppercase() || c == '_' || c.is_numeric())
         }
 
         match (self, other) {
@@ -459,11 +689,14 @@ fn rewrite_nested_use_tree(
         IndentStyle::Visual => shape.visual_indent(0),
     };
     for use_tree in use_tree_list {
-        let mut list_item = use_tree.list_item.clone()?;
-        list_item.item = use_tree.rewrite(context, nested_shape);
-        list_items.push(list_item);
+        if let Some(mut list_item) = use_tree.list_item.clone() {
+            list_item.item = use_tree.rewrite(context, nested_shape);
+            list_items.push(list_item);
+        } else {
+            list_items.push(ListItem::from_str(use_tree.rewrite(context, nested_shape)?));
+        }
     }
-    let (tactic, remaining_width) = if use_tree_list.iter().any(|use_segment| {
+    let has_nested_list = use_tree_list.iter().any(|use_segment| {
         use_segment
             .path
             .last()
@@ -471,35 +704,34 @@ fn rewrite_nested_use_tree(
                 UseSegment::List(..) => true,
                 _ => false,
             })
-    }) {
-        (DefinitiveListTactic::Vertical, 0)
+    });
+
+    let remaining_width = if has_nested_list {
+        0
     } else {
-        let remaining_width = shape.width.checked_sub(2).unwrap_or(0);
-        let tactic = definitive_tactic(
-            &list_items,
-            context.config.imports_layout(),
-            Separator::Comma,
-            remaining_width,
-        );
-        (tactic, remaining_width)
+        shape.width.saturating_sub(2)
     };
 
+    let tactic = definitive_tactic(
+        &list_items,
+        context.config.imports_layout(),
+        Separator::Comma,
+        remaining_width,
+    );
+
     let ends_with_newline = context.config.imports_indent() == IndentStyle::Block
         && tactic != DefinitiveListTactic::Horizontal;
-    let fmt = ListFormatting {
-        tactic,
-        separator: ",",
-        trailing_separator: if ends_with_newline {
-            context.config.trailing_comma()
-        } else {
-            SeparatorTactic::Never
-        },
-        separator_place: SeparatorPlace::Back,
-        shape: nested_shape,
-        ends_with_newline,
-        preserve_newline: true,
-        config: context.config,
+    let trailing_separator = if ends_with_newline {
+        context.config.trailing_comma()
+    } else {
+        SeparatorTactic::Never
     };
+    let fmt = ListFormatting::new(nested_shape, context.config)
+        .tactic(tactic)
+        .trailing_separator(trailing_separator)
+        .ends_with_newline(ends_with_newline)
+        .preserve_newline(true)
+        .nested(has_nested_list);
 
     let list_str = write_list(&list_items, &fmt)?;
 
@@ -521,7 +753,7 @@ fn rewrite_nested_use_tree(
 
 impl Rewrite for UseSegment {
     fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
-        Some(match *self {
+        Some(match self {
             UseSegment::Ident(ref ident, Some(ref rename)) => format!("{} as {}", ident, rename),
             UseSegment::Ident(ref ident, None) => ident.clone(),
             UseSegment::Slf(Some(ref rename)) => format!("self as {}", rename),
@@ -560,7 +792,7 @@ fn rewrite(&self, context: &RewriteContext, mut shape: Shape) -> Option<String>
 #[cfg(test)]
 mod test {
     use super::*;
-    use syntax::codemap::DUMMY_SP;
+    use syntax::source_map::DUMMY_SP;
 
     // Parse the path part of an import. This parser is not robust and is only
     // suitable for use in a test harness.
@@ -577,9 +809,11 @@ impl<'a> Parser<'a> {
             fn bump(&mut self) {
                 self.input.next().unwrap();
             }
+
             fn eat(&mut self, c: char) {
                 assert!(self.input.next().unwrap() == c);
             }
+
             fn push_segment(
                 result: &mut Vec<UseSegment>,
                 buf: &mut String,
@@ -603,6 +837,7 @@ fn push_segment(
                     }
                 }
             }
+
             fn parse_in_list(&mut self) -> UseTree {
                 let mut result = vec![];
                 let mut buf = String::new();
@@ -682,6 +917,60 @@ fn parse_list(&mut self) -> Vec<UseTree> {
         parser.parse_in_list()
     }
 
+    macro parse_use_trees($($s:expr),* $(,)*) {
+        vec![
+            $(parse_use_tree($s),)*
+        ]
+    }
+
+    #[test]
+    fn test_use_tree_merge() {
+        macro test_merge([$($input:expr),* $(,)*], [$($output:expr),* $(,)*]) {
+            assert_eq!(
+                merge_use_trees(parse_use_trees!($($input,)*)),
+                parse_use_trees!($($output,)*),
+            );
+        }
+
+        test_merge!(["a::b::{c, d}", "a::b::{e, f}"], ["a::b::{c, d, e, f}"]);
+        test_merge!(["a::b::c", "a::b"], ["a::b::{self, c}"]);
+        test_merge!(["a::b", "a::b"], ["a::b"]);
+        test_merge!(["a", "a::b", "a::b::c"], ["a::{self, b::{self, c}}"]);
+        test_merge!(
+            ["a::{b::{self, c}, d::e}", "a::d::f"],
+            ["a::{b::{self, c}, d::{e, f}}"]
+        );
+        test_merge!(
+            ["a::d::f", "a::{b::{self, c}, d::e}"],
+            ["a::{b::{self, c}, d::{e, f}}"]
+        );
+        test_merge!(
+            ["a::{c, d, b}", "a::{d, e, b, a, f}", "a::{f, g, c}"],
+            ["a::{a, b, c, d, e, f, g}"]
+        );
+    }
+
+    #[test]
+    fn test_use_tree_flatten() {
+        assert_eq!(
+            parse_use_tree("a::b::{c, d, e, f}").flatten(),
+            parse_use_trees!("a::b::c", "a::b::d", "a::b::e", "a::b::f",)
+        );
+
+        assert_eq!(
+            parse_use_tree("a::b::{c::{d, e, f}, g, h::{i, j, k}}").flatten(),
+            parse_use_trees![
+                "a::b::c::d",
+                "a::b::c::e",
+                "a::b::c::f",
+                "a::b::g",
+                "a::b::h::i",
+                "a::b::h::j",
+                "a::b::h::k",
+            ]
+        );
+    }
+
     #[test]
     fn test_use_tree_normalize() {
         assert_eq!(parse_use_tree("a::self").normalize(), parse_use_tree("a"));