clang-format: introduce InlineOnly short function style

Summary:
This is the same as Inline, except it does not imply all empty
functions are merged: with this style, empty functions are merged only
if they also match the 'inline' criteria (i.e. defined in a class).

This is helpful to avoid inlining functions in implementations files.

Reviewers: djasper, krasimir

Reviewed By: djasper

Subscribers: klimek, rengolin, cfe-commits

Differential Revision: https://reviews.llvm.org/D34399

llvm-svn: 305912

clang/include/clang/Format/Format.h

@@ -184,9 +184,23 @@ struct FormatStyle {
   enum ShortFunctionStyle {
     /// \brief Never merge functions into a single line.
     SFS_None,
+    /// \brief Only merge functions defined inside a class. Same as "inline",
+    /// except it does not implies "empty": i.e. top level empty functions
+    /// are not merged either.
+    /// \code
+    ///   class Foo {
+    ///     void f() { foo(); }
+    ///   };
+    ///   void f() {
+    ///     foo();
+    ///   }
+    ///   void f() {
+    ///   }
+    /// \endcode
+    SFS_InlineOnly,
     /// \brief Only merge empty functions.
     /// \code
-    ///   void f() { bar(); }
+    ///   void f() {}
     ///   void f2() {
     ///     bar2();
     ///   }
@@ -197,6 +211,10 @@ struct FormatStyle {
     ///   class Foo {
     ///     void f() { foo(); }
     ///   };
+    ///   void f() {
+    ///     foo();
+    ///   }
+    ///   void f() {}
     /// \endcode
     SFS_Inline,
     /// \brief Merge all functions fitting on a single line.

clang/lib/Format/Format.cpp

@@ -97,6 +97,7 @@ template <> struct ScalarEnumerationTraits<FormatStyle::ShortFunctionStyle> {
     IO.enumCase(Value, "All", FormatStyle::SFS_All);
     IO.enumCase(Value, "true", FormatStyle::SFS_All);
     IO.enumCase(Value, "Inline", FormatStyle::SFS_Inline);
+    IO.enumCase(Value, "InlineOnly", FormatStyle::SFS_InlineOnly);
     IO.enumCase(Value, "Empty", FormatStyle::SFS_Empty);
   }
 };

clang/lib/Format/TokenAnnotator.cpp

@@ -2480,8 +2480,8 @@ bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
       return Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_None ||
              Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_Empty ||
              (Left.NestingLevel == 0 && Line.Level == 0 &&
-              Style.AllowShortFunctionsOnASingleLine ==
-                  FormatStyle::SFS_Inline);
+              Style.AllowShortFunctionsOnASingleLine &
+                  FormatStyle::SFS_InlineOnly);
   } else if (Style.Language == FormatStyle::LK_Java) {
     if (Right.is(tok::plus) && Left.is(tok::string_literal) && Right.Next &&
         Right.Next->is(tok::string_literal))

clang/lib/Format/UnwrappedLineFormatter.cpp

@@ -226,7 +226,7 @@ private:
         Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_All ||
         (Style.AllowShortFunctionsOnASingleLine >= FormatStyle::SFS_Empty &&
          I[1]->First->is(tok::r_brace)) ||
-        (Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_Inline &&
+        (Style.AllowShortFunctionsOnASingleLine & FormatStyle::SFS_InlineOnly &&
          TheLine->Level != 0);
 
     if (Style.CompactNamespaces) {

clang/unittests/Format/FormatTest.cpp

@@ -6509,6 +6509,52 @@ TEST_F(FormatTest, PullInlineFunctionDefinitionsIntoSingleLine) {
                MergeInlineOnly);
 }
 
+TEST_F(FormatTest, PullInlineOnlyFunctionDefinitionsIntoSingleLine) {
+  FormatStyle MergeInlineOnly = getLLVMStyle();
+  MergeInlineOnly.AllowShortFunctionsOnASingleLine =
+      FormatStyle::SFS_InlineOnly;
+  verifyFormat("class C {\n"
+               "  int f() { return 42; }\n"
+               "};",
+               MergeInlineOnly);
+  verifyFormat("int f() {\n"
+               "  return 42;\n"
+               "}",
+               MergeInlineOnly);
+
+  // SFS_InlineOnly does not imply SFS_Empty
+  verifyFormat("class C {\n"
+               "  int f() {}\n"
+               "};",
+               MergeInlineOnly);
+  verifyFormat("int f() {\n"
+               "}",
+               MergeInlineOnly);
+
+  // Also verify behavior when BraceWrapping.AfterFunction = true
+  MergeInlineOnly.BreakBeforeBraces = FormatStyle::BS_Custom;
+  MergeInlineOnly.BraceWrapping.AfterFunction = true;
+  verifyFormat("class C {\n"
+               "  int f() { return 42; }\n"
+               "};",
+               MergeInlineOnly);
+  verifyFormat("int f()\n"
+               "{\n"
+               "  return 42;\n"
+               "}",
+               MergeInlineOnly);
+
+  // SFS_InlineOnly does not imply SFS_Empty
+  verifyFormat("int f()\n"
+               "{\n"
+               "}",
+               MergeInlineOnly);
+  verifyFormat("class C {\n"
+               "  int f() {}\n"
+               "};",
+               MergeInlineOnly);
+}
+
 TEST_F(FormatTest, SplitEmptyFunctionBody) {
   FormatStyle Style = getLLVMStyle();
   Style.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_None;