Follow indent style config when formatting attrs

Author: topecongiro

src/attr.rs

@@ -10,6 +10,7 @@
 
 //! Format attributes and meta items.
 
+use config::IndentStyle;
 use config::lists::*;
 use syntax::ast;
 use syntax::codemap::Span;
@@ -202,11 +203,16 @@ impl Rewrite for ast::MetaItem {
             ast::MetaItemKind::Word => String::from(&*self.name.as_str()),
             ast::MetaItemKind::List(ref list) => {
                 let name = self.name.as_str();
-                // 1 = `(`, 2 = `]` and `)`
-                let item_shape = shape
-                    .visual_indent(0)
-                    .shrink_left(name.len() + 1)
-                    .and_then(|s| s.sub_width(2))?;
+                let item_shape = match context.config.indent_style() {
+                    IndentStyle::Block => shape
+                        .block_indent(context.config.tab_spaces())
+                        .with_max_width(context.config),
+                    // 1 = `(`, 2 = `]` and `)`
+                    IndentStyle::Visual => shape
+                        .visual_indent(0)
+                        .shrink_left(name.len() + 1)
+                        .and_then(|s| s.sub_width(2))?,
+                };
                 let items = itemize_list(
                     context.snippet_provider,
                     list.iter(),
@@ -240,7 +246,17 @@ impl Rewrite for ast::MetaItem {
                     preserve_newline: false,
                     config: context.config,
                 };
-                format!("{}({})", name, write_list(&item_vec, &fmt)?)
+                let item_str = write_list(&item_vec, &fmt)?;
+                let one_line_budget = shape.offset_left(name.len())?.sub_width(2)?.width;
+                if context.config.indent_style() == IndentStyle::Visual
+                    || (!item_str.contains('\n') && item_str.len() <= one_line_budget)
+                {
+                    format!("{}({})", name, item_str)
+                } else {
+                    let indent = shape.indent.to_string_with_newline(context.config);
+                    let nested_indent = item_shape.indent.to_string_with_newline(context.config);
+                    format!("{}({}{}{})", name, nested_indent, item_str, indent)
+                }
             }
             ast::MetaItemKind::NameValue(ref literal) => {
                 let name = self.name.as_str();