clang-format: add options to merge empty record body

Summary:
This patch introduces a few extra BraceWrapping options, similar to
`SplitEmptyFunction`, to allow merging empty 'record' bodies (e.g.
class, struct, union and namespace):
* SplitEmptyClass
* SplitEmptyStruct
* SplitEmptyUnion
* SplitEmptyNamespace

The `SplitEmptyFunction` option name has also been simplified/
shortened (from `SplitEmptyFunctionBody`).

These options are helpful when the correspond AfterXXX option is
enabled, to allow merging the empty record:

  class Foo
  {};

In addition, this fixes an unexpected merging of short records, when
the AfterXXXX options are used, which caused to be formatted like
this:

  class Foo
  { void Foo(); };

This is now properly formatted as:

  class Foo
  {
     void Foo();
  };

Reviewers: djasper, krasimir

Reviewed By: djasper

Subscribers: cfe-commits, klimek

Differential Revision: https://reviews.llvm.org/D34395

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@306874 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 23 insertions, 5 deletions

diff --git a/lib/Format/UnwrappedLineFormatter.cpp b/lib/Format/UnwrappedLineFormatter.cpp
index 8836c07cac..2005a28229 100644
--- a/lib/Format/UnwrappedLineFormatter.cpp
+++ b/lib/Format/UnwrappedLineFormatter.cpp
@@ -136,10 +136,7 @@ private:
 
 bool isNamespaceDeclaration(const AnnotatedLine *Line) {
   const FormatToken *NamespaceTok = Line->First;
-  // Detect "(inline)? namespace" in the beginning of a line.
-  if (NamespaceTok->is(tok::kw_inline))
-    NamespaceTok = NamespaceTok->getNextNonComment();
-  return NamespaceTok && NamespaceTok->is(tok::kw_namespace);
+  return NamespaceTok && NamespaceTok->getNamespaceToken();
 }
 
 bool isEndOfNamespace(const AnnotatedLine *Line,
@@ -216,10 +213,31 @@ private:
 
     if (TheLine->Last->is(TT_FunctionLBrace) &&
         TheLine->First == TheLine->Last &&
-        !Style.BraceWrapping.SplitEmptyFunctionBody &&
+        !Style.BraceWrapping.SplitEmptyFunction &&
         I[1]->First->is(tok::r_brace))
       return tryMergeSimpleBlock(I, E, Limit);
 
+    // Handle empty record blocks where the brace has already been wrapped
+    if (TheLine->Last->is(tok::l_brace) && TheLine->First == TheLine->Last &&
+        I != AnnotatedLines.begin()) {
+      bool EmptyBlock = I[1]->First->is(tok::r_brace);
+
+      const FormatToken *Tok = I[-1]->First;
+      if (Tok && Tok->is(tok::comment))
+        Tok = Tok->getNextNonComment();
+
+      if (Tok && Tok->getNamespaceToken())
+        return !Style.BraceWrapping.SplitEmptyNamespace && EmptyBlock
+            ? tryMergeSimpleBlock(I, E, Limit) : 0;
+
+      if (Tok && Tok->is(tok::kw_typedef))
+        Tok = Tok->getNextNonComment();
+      if (Tok && Tok->isOneOf(tok::kw_class, tok::kw_struct, tok::kw_union,
+                              Keywords.kw_interface))
+        return !Style.BraceWrapping.SplitEmptyRecord && EmptyBlock
+            ? tryMergeSimpleBlock(I, E, Limit) : 0;
+    }
+
     // FIXME: TheLine->Level != 0 might or might not be the right check to do.
     // If necessary, change to something smarter.
     bool MergeShortFunctions =