Fix empty body format, add fn_empty_single_line option, refactor block tests

src/config.rs

@@ -269,6 +269,7 @@ create_config! {
     newline_style: NewlineStyle, NewlineStyle::Unix, "Unix or Windows line endings";
     fn_brace_style: BraceStyle, BraceStyle::SameLineWhere, "Brace style for functions";
     item_brace_style: BraceStyle, BraceStyle::SameLineWhere, "Brace style for structs and enums";
+    fn_empty_single_line: bool, true, "Put empty-body functions on a single line";
     fn_single_line: bool, false, "Put single-expression functions on a single line";
     fn_return_indent: ReturnIndent, ReturnIndent::WithArgs,
         "Location of return type in function declaration";

src/expr.rs

@@ -705,36 +705,25 @@ fn single_line_if_else(context: &RewriteContext,
     None
 }
 
-// Checks that a block contains no statements, an expression and no comments.
-fn is_simple_block(block: &ast::Block, codemap: &CodeMap) -> bool {
-    if !block.stmts.is_empty() || block.expr.is_none() {
-        return false;
+fn block_contains_comment(block: &ast::Block, codemap: &CodeMap) -> bool {
+    let snippet = codemap.span_to_snippet(block.span).unwrap();
+    contains_comment(&snippet)
 }
 
-    let snippet = codemap.span_to_snippet(block.span).unwrap();
-
-    !contains_comment(&snippet)
+// Checks that a block contains no statements, an expression and no comments.
+pub fn is_simple_block(block: &ast::Block, codemap: &CodeMap) -> bool {
+    block.stmts.is_empty() && block.expr.is_some() && !block_contains_comment(block, codemap)
 }
 
 /// Checks whether a block contains at most one statement or expression, and no comments.
 pub fn is_simple_block_stmt(block: &ast::Block, codemap: &CodeMap) -> bool {
-    if (!block.stmts.is_empty() && block.expr.is_some()) ||
-       (block.stmts.len() != 1 && block.expr.is_none()) {
-        return false;
-    }
-
-    let snippet = codemap.span_to_snippet(block.span).unwrap();
-    !contains_comment(&snippet)
+    (block.stmts.is_empty() || (block.stmts.len() == 1 && block.expr.is_none())) &&
+    !block_contains_comment(block, codemap)
 }
 
 /// Checks whether a block contains no statements, expressions, or comments.
 pub fn is_empty_block(block: &ast::Block, codemap: &CodeMap) -> bool {
-    if !block.stmts.is_empty() || block.expr.is_some() {
-        return false;
-    }
-
-    let snippet = codemap.span_to_snippet(block.span).unwrap();
-    !contains_comment(&snippet)
+    block.stmts.is_empty() && block.expr.is_none() && !block_contains_comment(block, codemap)
 }
 
 // inter-match-arm-comment-rules:

src/items.rs

@@ -448,19 +448,18 @@ impl<'a> FmtVisitor<'a> {
     }
 
     pub fn rewrite_single_line_fn(&self,
-                                  fn_rewrite: &Option<String>,
+                                  fn_str: &str,
                                   block: &ast::Block)
                                   -> Option<String> {
 
-        let fn_str = match *fn_rewrite {
-            Some(ref s) if !s.contains('\n') => s,
-            _ => return None,
-        };
+        if fn_str.contains('\n') {
+            return None;
+        }
 
         let codemap = self.get_context().codemap;
 
-        if is_empty_block(block, codemap) &&
-           self.block_indent.width() + fn_str.len() + 3 <= self.config.max_width {
+        if self.config.fn_empty_single_line && is_empty_block(block, codemap) &&
+           self.block_indent.width() + fn_str.len() + 2 <= self.config.max_width {
             return Some(format!("{}{{}}", fn_str));
         }
 
@@ -488,7 +487,7 @@ impl<'a> FmtVisitor<'a> {
             };
 
             if let Some(res) = rewrite {
-                let width = self.block_indent.width() + fn_str.len() + res.len() + 3;
+                let width = self.block_indent.width() + fn_str.len() + res.len() + 4;
                 if !res.contains('\n') && width <= self.config.max_width {
                     return Some(format!("{}{{ {} }}", fn_str, res));
                 }

src/visitor.rs

@@ -154,16 +154,15 @@ impl<'a> FmtVisitor<'a> {
             visit::FnKind::Closure => None,
         };
 
-        if let Some(ref single_line_fn) = self.rewrite_single_line_fn(&rewrite, &b) {
+        if let Some(fn_str) = rewrite {
             self.format_missing_with_indent(s.lo);
+            if let Some(ref single_line_fn) = self.rewrite_single_line_fn(&fn_str, &b) {
                 self.buffer.push_str(single_line_fn);
                 self.last_pos = b.span.hi;
                 return;
-        }
-
-        if let Some(fn_str) = rewrite {
-            self.format_missing_with_indent(s.lo);
+            } else {
                 self.buffer.push_str(&fn_str);
+            }
         } else {
             self.format_missing(b.span.lo);
         }