Merge pull request #1948 from topecongiro/issue-1137

Use write_list() to format imports

2 files changed, 147 insertions, 137 deletions

diff --git a/src/imports.rs b/src/imports.rs
index 33efce19a40..7cfe5d8b6b9 100644
--- a/src/imports.rs
+++ b/src/imports.rs
@@ -8,20 +8,21 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::cmp::{self, Ordering};
+use std::cmp::Ordering;
 
 use syntax::{ast, ptr};
 use syntax::codemap::{BytePos, Span};
 
-use Shape;
+use {Shape, Spanned};
 use codemap::SpanUtils;
+use comment::combine_strs_with_missing_comments;
 use config::IndentStyle;
 use lists::{definitive_tactic, itemize_list, write_list, DefinitiveListTactic, ListFormatting,
             ListItem, Separator, SeparatorPlace, SeparatorTactic};
 use rewrite::{Rewrite, RewriteContext};
 use types::{rewrite_path, PathContext};
-use utils;
-use visitor::FmtVisitor;
+use utils::{format_visibility, mk_sp};
+use visitor::{rewrite_extern_crate, FmtVisitor};
 
 fn path_of(a: &ast::ViewPath_) -> &ast::Path {
     match *a {
@@ -185,95 +186,115 @@ impl Rewrite for ast::ViewPath {
     }
 }
 
-impl<'a> FmtVisitor<'a> {
-    pub fn format_imports(&mut self, use_items: &[ptr::P<ast::Item>]) {
-        // Find the location immediately before the first use item in the run. This must not lie
-        // before the current `self.last_pos`
-        let pos_before_first_use_item = use_items
-            .first()
-            .map(|p_i| {
-                cmp::max(
-                    self.last_pos,
-                    p_i.attrs
-                        .iter()
-                        .map(|attr| attr.span.lo())
-                        .min()
-                        .unwrap_or(p_i.span.lo()),
-                )
-            })
-            .unwrap_or(self.last_pos);
-        // Construct a list of pairs, each containing a `use` item and the start of span before
-        // that `use` item.
-        let mut last_pos_of_prev_use_item = pos_before_first_use_item;
-        let mut ordered_use_items = use_items
-            .iter()
-            .map(|p_i| {
-                let new_item = (&*p_i, last_pos_of_prev_use_item);
-                last_pos_of_prev_use_item = p_i.span.hi();
-                new_item
-            })
-            .collect::<Vec<_>>();
-        let pos_after_last_use_item = last_pos_of_prev_use_item;
-        // Order the imports by view-path & other import path properties
-        ordered_use_items.sort_by(|a, b| {
-            compare_use_items(&self.get_context(), a.0, b.0).unwrap()
-        });
-        // First, output the span before the first import
-        let prev_span_str = self.snippet(utils::mk_sp(self.last_pos, pos_before_first_use_item));
-        // Look for purely trailing space at the start of the prefix snippet before a linefeed, or
-        // a prefix that's entirely horizontal whitespace.
-        let prefix_span_start = match prev_span_str.find('\n') {
-            Some(offset) if prev_span_str[..offset].trim().is_empty() => {
-                self.last_pos + BytePos(offset as u32)
-            }
-            None if prev_span_str.trim().is_empty() => pos_before_first_use_item,
-            _ => self.last_pos,
-        };
-        // Look for indent (the line part preceding the use is all whitespace) and excise that
-        // from the prefix
-        let span_end = match prev_span_str.rfind('\n') {
-            Some(offset) if prev_span_str[offset..].trim().is_empty() => {
-                self.last_pos + BytePos(offset as u32)
+// Rewrite `use foo;` WITHOUT attributes.
+fn rewrite_import(
+    context: &RewriteContext,
+    vis: &ast::Visibility,
+    vp: &ast::ViewPath,
+    attrs: &[ast::Attribute],
+    shape: Shape,
+) -> Option<String> {
+    let vis = format_visibility(vis);
+    // 4 = `use `, 1 = `;`
+    let rw = shape
+        .offset_left(vis.len() + 4)
+        .and_then(|shape| shape.sub_width(1))
+        .and_then(|shape| match vp.node {
+            // If we have an empty path list with no attributes, we erase it
+            ast::ViewPath_::ViewPathList(_, ref path_list)
+                if path_list.is_empty() && attrs.is_empty() =>
+            {
+                Some("".into())
             }
-            _ => pos_before_first_use_item,
-        };
+            _ => vp.rewrite(context, shape),
+        });
+    match rw {
+        Some(ref s) if !s.is_empty() => Some(format!("{}use {};", vis, s)),
+        _ => rw,
+    }
+}
 
-        self.last_pos = prefix_span_start;
-        self.format_missing(span_end);
-        for ordered in ordered_use_items {
-            // Fake out the formatter by setting `self.last_pos` to the appropriate location before
-            // each item before visiting it.
-            self.last_pos = ordered.1;
-            self.visit_item(ordered.0);
+fn rewrite_imports(
+    context: &RewriteContext,
+    use_items: &[ptr::P<ast::Item>],
+    shape: Shape,
+    span: Span,
+) -> Option<String> {
+    let items = itemize_list(
+        context.codemap,
+        use_items.iter(),
+        "",
+        |item| item.span().lo(),
+        |item| item.span().hi(),
+        |item| {
+            let attrs_str = try_opt!(item.attrs.rewrite(context, shape));
+
+            let missed_span = if item.attrs.is_empty() {
+                mk_sp(item.span.lo(), item.span.lo())
+            } else {
+                mk_sp(item.attrs.last().unwrap().span.hi(), item.span.lo())
+            };
+
+            let item_str = match item.node {
+                ast::ItemKind::Use(ref vp) => {
+                    try_opt!(rewrite_import(context, &item.vis, vp, &item.attrs, shape))
+                }
+                ast::ItemKind::ExternCrate(..) => try_opt!(rewrite_extern_crate(context, item)),
+                _ => return None,
+            };
+
+            combine_strs_with_missing_comments(
+                context,
+                &attrs_str,
+                &item_str,
+                missed_span,
+                shape,
+                false,
+            )
+        },
+        span.lo(),
+        span.hi(),
+        false,
+    );
+    let mut item_pair_vec: Vec<_> = items.zip(use_items.iter()).collect();
+    item_pair_vec.sort_by(|a, b| compare_use_items(context, a.1, b.1).unwrap());
+    let item_vec: Vec<_> = item_pair_vec.into_iter().map(|pair| pair.0).collect();
+
+    let fmt = ListFormatting {
+        tactic: DefinitiveListTactic::Vertical,
+        separator: "",
+        trailing_separator: SeparatorTactic::Never,
+        separator_place: SeparatorPlace::Back,
+        shape: shape,
+        ends_with_newline: true,
+        preserve_newline: false,
+        config: context.config,
+    };
+
+    write_list(&item_vec, &fmt)
+}
+
+impl<'a> FmtVisitor<'a> {
+    pub fn format_imports(&mut self, use_items: &[ptr::P<ast::Item>]) {
+        if use_items.is_empty() {
+            return;
         }
-        self.last_pos = pos_after_last_use_item;
+
+        let lo = use_items.first().unwrap().span().lo();
+        let hi = use_items.last().unwrap().span().hi();
+        let span = mk_sp(lo, hi);
+        let rw = rewrite_imports(&self.get_context(), use_items, self.shape(), span);
+        self.push_rewrite(span, rw);
     }
 
-    pub fn format_import(
-        &mut self,
-        vis: &ast::Visibility,
-        vp: &ast::ViewPath,
-        span: Span,
-        attrs: &[ast::Attribute],
-    ) {
-        let vis = utils::format_visibility(vis);
-        // 4 = `use `, 1 = `;`
-        let rw = self.shape()
-            .offset_left(vis.len() + 4)
-            .and_then(|shape| shape.sub_width(1))
-            .and_then(|shape| match vp.node {
-                // If we have an empty path list with no attributes, we erase it
-                ast::ViewPath_::ViewPathList(_, ref path_list)
-                    if path_list.is_empty() && attrs.is_empty() =>
-                {
-                    Some("".into())
-                }
-                _ => vp.rewrite(&self.get_context(), shape),
-            });
+    pub fn format_import(&mut self, item: &ast::Item, vp: &ast::ViewPath) {
+        let span = item.span;
+        let shape = self.shape();
+        let rw = rewrite_import(&self.get_context(), &item.vis, vp, &item.attrs, shape);
         match rw {
             Some(ref s) if s.is_empty() => {
                 // Format up to last newline
-                let prev_span = utils::mk_sp(self.last_pos, source!(self, span).lo());
+                let prev_span = mk_sp(self.last_pos, source!(self, span).lo());
                 let span_end = match self.snippet(prev_span).rfind('\n') {
                     Some(offset) => self.last_pos + BytePos(offset as u32),
                     None => source!(self, span).lo(),
@@ -282,7 +303,6 @@ impl<'a> FmtVisitor<'a> {
                 self.last_pos = source!(self, span).hi();
             }
             Some(ref s) => {
-                let s = format!("{}use {};", vis, s);
                 self.format_missing_with_indent(source!(self, span).lo());
                 self.buffer.push_str(&s);
                 self.last_pos = source!(self, span).hi();
diff --git a/src/visitor.rs b/src/visitor.rs
index fb8a6f95b21..832883c2c3e 100644
--- a/src/visitor.rs
+++ b/src/visitor.rs
@@ -22,8 +22,9 @@ use comment::{contains_comment, recover_missing_comment_in_span, CodeCharKind, C
               FindUncommented};
 use comment::rewrite_comment;
 use config::{BraceStyle, Config};
-use items::{format_impl, format_trait, rewrite_associated_impl_type, rewrite_associated_type,
-            rewrite_static, rewrite_type_alias};
+use items::{format_impl, format_struct, format_struct_struct, format_trait,
+            rewrite_associated_impl_type, rewrite_associated_type, rewrite_static,
+            rewrite_type_alias};
 use lists::{itemize_list, write_list, DefinitiveListTactic, ListFormatting, SeparatorPlace,
             SeparatorTactic};
 use macros::{rewrite_macro, MacroPosition};
@@ -296,7 +297,8 @@ impl<'a> FmtVisitor<'a> {
         // complex in the module case. It is complex because the module could be
         // in a separate file and there might be attributes in both files, but
         // the AST lumps them all together.
-        let mut attrs = item.attrs.clone();
+        let filterd_attrs;
+        let mut attrs = &item.attrs;
         match item.node {
             ast::ItemKind::Mod(ref m) => {
                 let outer_file = self.codemap.lookup_char_pos(item.span.lo()).file;
@@ -314,7 +316,7 @@ impl<'a> FmtVisitor<'a> {
                 } else {
                     // Module is not inline and should not be skipped. We want
                     // to process only the attributes in the current file.
-                    let filterd_attrs = item.attrs
+                    filterd_attrs = item.attrs
                         .iter()
                         .filter_map(|a| {
                             let attr_file = self.codemap.lookup_char_pos(a.span.lo()).file;
@@ -328,7 +330,7 @@ impl<'a> FmtVisitor<'a> {
                     // Assert because if we should skip it should be caught by
                     // the above case.
                     assert!(!self.visit_attrs(&filterd_attrs, ast::AttrStyle::Outer));
-                    attrs = filterd_attrs;
+                    attrs = &filterd_attrs;
                 }
             }
             _ => if self.visit_attrs(&item.attrs, ast::AttrStyle::Outer) {
@@ -338,62 +340,38 @@ impl<'a> FmtVisitor<'a> {
         }
 
         match item.node {
-            ast::ItemKind::Use(ref vp) => {
-                self.format_import(&item.vis, vp, item.span, &item.attrs);
-            }
+            ast::ItemKind::Use(ref vp) => self.format_import(&item, vp),
             ast::ItemKind::Impl(..) => {
-                self.format_missing_with_indent(source!(self, item.span).lo());
                 let snippet = self.snippet(item.span);
                 let where_span_end = snippet
                     .find_uncommented("{")
                     .map(|x| (BytePos(x as u32)) + source!(self, item.span).lo());
-                if let Some(impl_str) =
-                    format_impl(&self.get_context(), item, self.block_indent, where_span_end)
-                {
-                    self.buffer.push_str(&impl_str);
-                    self.last_pos = source!(self, item.span).hi();
-                }
+                let rw = format_impl(&self.get_context(), item, self.block_indent, where_span_end);
+                self.push_rewrite(item.span, rw);
             }
             ast::ItemKind::Trait(..) => {
-                self.format_missing_with_indent(item.span.lo());
-                if let Some(trait_str) = format_trait(&self.get_context(), item, self.block_indent)
-                {
-                    self.buffer.push_str(&trait_str);
-                    self.last_pos = source!(self, item.span).hi();
-                }
+                let rw = format_trait(&self.get_context(), item, self.block_indent);
+                self.push_rewrite(item.span, rw);
             }
             ast::ItemKind::ExternCrate(_) => {
-                self.format_missing_with_indent(source!(self, item.span).lo());
-                let new_str = self.snippet(item.span);
-                if contains_comment(&new_str) {
-                    self.buffer.push_str(&new_str)
-                } else {
-                    let no_whitespace =
-                        &new_str.split_whitespace().collect::<Vec<&str>>().join(" ");
-                    self.buffer
-                        .push_str(&Regex::new(r"\s;").unwrap().replace(no_whitespace, ";"));
-                }
-                self.last_pos = source!(self, item.span).hi();
+                let rw = rewrite_extern_crate(&self.get_context(), item);
+                self.push_rewrite(item.span, rw);
             }
             ast::ItemKind::Struct(ref def, ref generics) => {
-                let rewrite = {
-                    let indent = self.block_indent;
-                    let context = self.get_context();
-                    ::items::format_struct(
-                        &context,
-                        "struct ",
-                        item.ident,
-                        &item.vis,
-                        def,
-                        Some(generics),
-                        item.span,
-                        indent,
-                        None,
-                    ).map(|s| match *def {
-                        ast::VariantData::Tuple(..) => s + ";",
-                        _ => s,
-                    })
-                };
+                let rewrite = format_struct(
+                    &self.get_context(),
+                    "struct ",
+                    item.ident,
+                    &item.vis,
+                    def,
+                    Some(generics),
+                    item.span,
+                    self.block_indent,
+                    None,
+                ).map(|s| match *def {
+                    ast::VariantData::Tuple(..) => s + ";",
+                    _ => s,
+                });
                 self.push_rewrite(item.span, rewrite);
             }
             ast::ItemKind::Enum(ref def, ref generics) => {
@@ -474,7 +452,7 @@ impl<'a> FmtVisitor<'a> {
                 self.push_rewrite(item.span, rewrite);
             }
             ast::ItemKind::Union(ref def, ref generics) => {
-                let rewrite = ::items::format_struct_struct(
+                let rewrite = format_struct_struct(
                     &self.get_context(),
                     "union ",
                     item.ident,
@@ -1042,3 +1020,15 @@ fn get_derive_args(context: &RewriteContext, attr: &ast::Attribute) -> Option<Ve
         _ => None,
     })
 }
+
+// Rewrite `extern crate foo;` WITHOUT attributes.
+pub fn rewrite_extern_crate(context: &RewriteContext, item: &ast::Item) -> Option<String> {
+    assert!(is_extern_crate(item));
+    let new_str = context.snippet(item.span);
+    Some(if contains_comment(&new_str) {
+        new_str
+    } else {
+        let no_whitespace = &new_str.split_whitespace().collect::<Vec<&str>>().join(" ");
+        String::from(&*Regex::new(r"\s;").unwrap().replace(no_whitespace, ";"))
+    })
+}