Fixes bug 20587 - Add K&R break before braces style

Summary:
http://llvm.org/bugs/show_bug.cgi?id=20587

Added K&R style. It could be enabled by the following option:

```
BreakBeforeBraces: KernighanRitchie
```

This style is like `Attach`, but break *only* before function
declarations.

As I can see, no additional logic required to support this style, any
style different from other styles automagically satisfies K&R.

Reviewers: djasper

Reviewed By: djasper

Subscribers: cfe-commits, klimek

Differential Revision: http://reviews.llvm.org/D4837

llvm-svn: 215354

clang/lib/Format/UnwrappedLineParser.cpp

@@ -434,6 +434,19 @@ static bool IsGoogScope(const UnwrappedLine &Line) {
   return I->Tok->is(tok::l_paren);
 }
 
+static bool ShouldBreakBeforeBrace(const FormatStyle &Style,
+                                   const FormatToken &InitialToken) {
+  switch (Style.BreakBeforeBraces) {
+  case FormatStyle::BS_Linux:
+    return InitialToken.isOneOf(tok::kw_namespace, tok::kw_class);
+  case FormatStyle::BS_Allman:
+  case FormatStyle::BS_GNU:
+    return true;
+  default:
+    return false;
+  }
+}
+
 void UnwrappedLineParser::parseChildBlock() {
   FormatTok->BlockKind = BK_Block;
   nextToken();
@@ -1167,13 +1180,13 @@ void UnwrappedLineParser::parseTryCatch() {
 
 void UnwrappedLineParser::parseNamespace() {
   assert(FormatTok->Tok.is(tok::kw_namespace) && "'namespace' expected");
+
+  const FormatToken &InitialToken = *FormatTok;
   nextToken();
   if (FormatTok->Tok.is(tok::identifier))
     nextToken();
   if (FormatTok->Tok.is(tok::l_brace)) {
-    if (Style.BreakBeforeBraces == FormatStyle::BS_Linux ||
-        Style.BreakBeforeBraces == FormatStyle::BS_Allman ||
-        Style.BreakBeforeBraces == FormatStyle::BS_GNU)
+    if (ShouldBreakBeforeBrace(Style, InitialToken))
       addUnwrappedLine();
 
     bool AddLevel = Style.NamespaceIndentation == FormatStyle::NI_All ||
@@ -1327,6 +1340,7 @@ void UnwrappedLineParser::parseEnum() {
 }
 
 void UnwrappedLineParser::parseRecord() {
+  const FormatToken &InitialToken = *FormatTok;
   nextToken();
   if (FormatTok->isOneOf(tok::identifier, tok::coloncolon, tok::kw___attribute,
                          tok::kw___declspec, tok::kw_alignas)) {
@@ -1361,9 +1375,7 @@ void UnwrappedLineParser::parseRecord() {
     }
   }
   if (FormatTok->Tok.is(tok::l_brace)) {
-    if (Style.BreakBeforeBraces == FormatStyle::BS_Linux ||
-        Style.BreakBeforeBraces == FormatStyle::BS_Allman ||
-        Style.BreakBeforeBraces == FormatStyle::BS_GNU)
+    if (ShouldBreakBeforeBrace(Style, InitialToken))
       addUnwrappedLine();
 
     parseBlock(/*MustBeDeclaration=*/true, /*AddLevel=*/true,

clang/unittests/Format/FormatTest.cpp

@@ -7671,8 +7671,8 @@ TEST_F(FormatTest, ConfigurableSpaceBeforeAssignmentOperators) {
 }
 
 TEST_F(FormatTest, LinuxBraceBreaking) {
-  FormatStyle BreakBeforeBrace = getLLVMStyle();
-  BreakBeforeBrace.BreakBeforeBraces = FormatStyle::BS_Linux;
+  FormatStyle LinuxBraceStyle = getLLVMStyle();
+  LinuxBraceStyle.BreakBeforeBraces = FormatStyle::BS_Linux;
   verifyFormat("namespace a\n"
                "{\n"
                "class A\n"
@@ -7685,14 +7685,33 @@ TEST_F(FormatTest, LinuxBraceBreaking) {
                "    }\n"
                "  }\n"
                "  void g() { return; }\n"
-               "}\n"
-               "}",
-               BreakBeforeBrace);
+               "};\n"
+               "struct B {\n"
+               "  int x;\n"
+               "};\n"
+               "}\n",
+               LinuxBraceStyle);
+  verifyFormat("enum X {\n"
+               "  Y = 0,\n"
+               "}\n",
+               LinuxBraceStyle);
+  verifyFormat("struct S {\n"
+               "  int Type;\n"
+               "  union {\n"
+               "    int x;\n"
+               "    double y;\n"
+               "  } Value;\n"
+               "  class C\n"
+               "  {\n"
+               "    MyFavoriteType Value;\n"
+               "  } Class;\n"
+               "}\n",
+               LinuxBraceStyle);
 }
 
 TEST_F(FormatTest, StroustrupBraceBreaking) {
-  FormatStyle BreakBeforeBrace = getLLVMStyle();
-  BreakBeforeBrace.BreakBeforeBraces = FormatStyle::BS_Stroustrup;
+  FormatStyle StroustrupBraceStyle = getLLVMStyle();
+  StroustrupBraceStyle.BreakBeforeBraces = FormatStyle::BS_Stroustrup;
   verifyFormat("namespace a {\n"
                "class A {\n"
                "  void f()\n"
@@ -7703,9 +7722,12 @@ TEST_F(FormatTest, StroustrupBraceBreaking) {
                "    }\n"
                "  }\n"
                "  void g() { return; }\n"
-               "}\n"
-               "}",
-               BreakBeforeBrace);
+               "};\n"
+               "struct B {\n"
+               "  int x;\n"
+               "};\n"
+               "}\n",
+               StroustrupBraceStyle);
 
   verifyFormat("void foo()\n"
                "{\n"
@@ -7716,7 +7738,7 @@ TEST_F(FormatTest, StroustrupBraceBreaking) {
                "    b();\n"
                "  }\n"
                "}\n",
-               BreakBeforeBrace);
+               StroustrupBraceStyle);
 
   verifyFormat("#ifdef _DEBUG\n"
                "int foo(int i = 0)\n"
@@ -7726,7 +7748,7 @@ TEST_F(FormatTest, StroustrupBraceBreaking) {
                "{\n"
                "  return i;\n"
                "}",
-               BreakBeforeBrace);
+               StroustrupBraceStyle);
 
   verifyFormat("void foo() {}\n"
                "void bar()\n"
@@ -7738,7 +7760,7 @@ TEST_F(FormatTest, StroustrupBraceBreaking) {
                "{\n"
                "}\n"
                "#endif",
-               BreakBeforeBrace);
+               StroustrupBraceStyle);
 
   verifyFormat("void foobar() { int i = 5; }\n"
                "#ifdef _DEBUG\n"
@@ -7746,12 +7768,12 @@ TEST_F(FormatTest, StroustrupBraceBreaking) {
                "#else\n"
                "void bar() { foobar(); }\n"
                "#endif",
-               BreakBeforeBrace);
+               StroustrupBraceStyle);
 }
 
 TEST_F(FormatTest, AllmanBraceBreaking) {
-  FormatStyle BreakBeforeBrace = getLLVMStyle();
-  BreakBeforeBrace.BreakBeforeBraces = FormatStyle::BS_Allman;
+  FormatStyle AllmanBraceStyle = getLLVMStyle();
+  AllmanBraceStyle.BreakBeforeBraces = FormatStyle::BS_Allman;
   verifyFormat("namespace a\n"
                "{\n"
                "class A\n"
@@ -7765,9 +7787,13 @@ TEST_F(FormatTest, AllmanBraceBreaking) {
                "    }\n"
                "  }\n"
                "  void g() { return; }\n"
-               "}\n"
+               "};\n"
+               "struct B\n"
+               "{\n"
+               "  int x;\n"
+               "};\n"
                "}",
-               BreakBeforeBrace);
+               AllmanBraceStyle);
 
   verifyFormat("void f()\n"
                "{\n"
@@ -7784,7 +7810,7 @@ TEST_F(FormatTest, AllmanBraceBreaking) {
                "    c();\n"
                "  }\n"
                "}\n",
-               BreakBeforeBrace);
+               AllmanBraceStyle);
 
   verifyFormat("void f()\n"
                "{\n"
@@ -7801,7 +7827,7 @@ TEST_F(FormatTest, AllmanBraceBreaking) {
                "    c();\n"
                "  } while (false)\n"
                "}\n",
-               BreakBeforeBrace);
+               AllmanBraceStyle);
 
   verifyFormat("void f(int a)\n"
                "{\n"
@@ -7821,18 +7847,18 @@ TEST_F(FormatTest, AllmanBraceBreaking) {
                "    break;\n"
                "  }\n"
                "}\n",
-               BreakBeforeBrace);
+               AllmanBraceStyle);
 
   verifyFormat("enum X\n"
                "{\n"
                "  Y = 0,\n"
                "}\n",
-               BreakBeforeBrace);
+               AllmanBraceStyle);
   verifyFormat("enum X\n"
                "{\n"
                "  Y = 0\n"
                "}\n",
-               BreakBeforeBrace);
+               AllmanBraceStyle);
 
   verifyFormat("@interface BSApplicationController ()\n"
                "{\n"
@@ -7840,7 +7866,7 @@ TEST_F(FormatTest, AllmanBraceBreaking) {
                "  id _extraIvar;\n"
                "}\n"
                "@end\n",
-               BreakBeforeBrace);
+               AllmanBraceStyle);
 
   verifyFormat("#ifdef _DEBUG\n"
                "int foo(int i = 0)\n"
@@ -7850,7 +7876,7 @@ TEST_F(FormatTest, AllmanBraceBreaking) {
                "{\n"
                "  return i;\n"
                "}",
-               BreakBeforeBrace);
+               AllmanBraceStyle);
 
   verifyFormat("void foo() {}\n"
                "void bar()\n"
@@ -7862,7 +7888,7 @@ TEST_F(FormatTest, AllmanBraceBreaking) {
                "{\n"
                "}\n"
                "#endif",
-               BreakBeforeBrace);
+               AllmanBraceStyle);
 
   verifyFormat("void foobar() { int i = 5; }\n"
                "#ifdef _DEBUG\n"
@@ -7870,37 +7896,37 @@ TEST_F(FormatTest, AllmanBraceBreaking) {
                "#else\n"
                "void bar() { foobar(); }\n"
                "#endif",
-               BreakBeforeBrace);
+               AllmanBraceStyle);
 
   // This shouldn't affect ObjC blocks..
   verifyFormat("[self doSomeThingWithACompletionHandler:^{\n"
                "    // ...\n"
                "    int i;\n"
                "}];",
-               BreakBeforeBrace);
+               AllmanBraceStyle);
   verifyFormat("void (^block)(void) = ^{\n"
                "    // ...\n"
                "    int i;\n"
                "};",
-               BreakBeforeBrace);
+               AllmanBraceStyle);
   // .. or dict literals.
   verifyFormat("void f()\n"
                "{\n"
                "  [object someMethod:@{ @\"a\" : @\"b\" }];\n"
                "}",
-               BreakBeforeBrace);
+               AllmanBraceStyle);
 
-  BreakBeforeBrace.ColumnLimit = 19;
-  verifyFormat("void f() { int i; }", BreakBeforeBrace);
-  BreakBeforeBrace.ColumnLimit = 18;
+  AllmanBraceStyle.ColumnLimit = 19;
+  verifyFormat("void f() { int i; }", AllmanBraceStyle);
+  AllmanBraceStyle.ColumnLimit = 18;
   verifyFormat("void f()\n"
                "{\n"
                "  int i;\n"
                "}",
-               BreakBeforeBrace);
-  BreakBeforeBrace.ColumnLimit = 80;
+               AllmanBraceStyle);
+  AllmanBraceStyle.ColumnLimit = 80;
 
-  FormatStyle BreakBeforeBraceShortIfs = BreakBeforeBrace;
+  FormatStyle BreakBeforeBraceShortIfs = AllmanBraceStyle;
   BreakBeforeBraceShortIfs.AllowShortIfStatementsOnASingleLine = true;
   BreakBeforeBraceShortIfs.AllowShortLoopsOnASingleLine = true;
   verifyFormat("void f(bool b)\n"