[clang-format/ObjC] Correctly parse Objective-C methods with 'class' in name

Summary:
Please take a close look at this CL. I haven't touched much of
`UnwrappedLineParser` before, so I may have gotten things wrong.

Previously, clang-format would incorrectly format the following:

```
@implementation Foo

- (Class)class {
}

- (void)foo {
}

@end
```

as:

```
@implementation Foo

- (Class)class {
}

    - (void)foo {
}

@end
```

The problem is whenever `UnwrappedLineParser::parseStructuralElement()`
sees any of the keywords `class`, `struct`, or `enum`, it calls
`parseRecord()` to parse them as a C/C++ record.

This causes subsequent lines to be parsed incorrectly, which
causes them to be indented incorrectly.

In Objective-C/Objective-C++, these keywords are valid selector
components.

This diff fixes the issue by explicitly handling `+` and `-` lines
inside `@implementation` / `@interface` / `@protocol` blocks
and parsing them as Objective-C methods.

Test Plan: New tests added. Ran tests with:
  make -j16 FormatTests && ./tools/clang/unittests/Format/FormatTests

Reviewers: jolesiak, klimek

Reviewed By: jolesiak, klimek

Subscribers: klimek, cfe-commits, Wizard

Differential Revision: https://reviews.llvm.org/D47095

llvm-svn: 333553

clang/lib/Format/UnwrappedLineParser.cpp

@@ -2130,6 +2130,24 @@ void UnwrappedLineParser::parseRecord(bool ParseAsExpr) {
   // "} n, m;" will end up in one unwrapped line.
 }
 
+void UnwrappedLineParser::parseObjCMethod() {
+  assert(FormatTok->Tok.isOneOf(tok::l_paren, tok::identifier) &&
+         "'(' or identifier expected.");
+  do {
+    if (FormatTok->Tok.is(tok::semi)) {
+      nextToken();
+      addUnwrappedLine();
+      return;
+    } else if (FormatTok->Tok.is(tok::l_brace)) {
+      parseBlock(/*MustBeDeclaration=*/false);
+      addUnwrappedLine();
+      return;
+    } else {
+      nextToken();
+    }
+  } while (!eof());
+}
+
 void UnwrappedLineParser::parseObjCProtocolList() {
   assert(FormatTok->Tok.is(tok::less) && "'<' expected.");
   do {
@@ -2157,6 +2175,9 @@ void UnwrappedLineParser::parseObjCUntilAtEnd() {
       // Ignore stray "}". parseStructuralElement doesn't consume them.
       nextToken();
       addUnwrappedLine();
+    } else if (FormatTok->isOneOf(tok::minus, tok::plus)) {
+      nextToken();
+      parseObjCMethod();
     } else {
       parseStructuralElement();
     }

clang/lib/Format/UnwrappedLineParser.h

@@ -120,6 +120,7 @@ private:
   // parses the record as a child block, i.e. if the class declaration is an
   // expression.
   void parseRecord(bool ParseAsExpr = false);
+  void parseObjCMethod();
   void parseObjCProtocolList();
   void parseObjCUntilAtEnd();
   void parseObjCInterfaceOrImplementation();

clang/unittests/Format/FormatTestObjC.cpp

@@ -328,7 +328,14 @@ TEST_F(FormatTestObjC, FormatObjCInterface) {
                "}\n"
                "+ (id)init;\n"
                "@end");
-
+  verifyFormat("@interface Foo\n"
+               "- (void)foo {\n"
+               "}\n"
+               "@end\n"
+               "@implementation Bar\n"
+               "- (void)bar {\n"
+               "}\n"
+               "@end");
   Style.ColumnLimit = 40;
   verifyFormat("@interface ccccccccccccc () <\n"
                "    ccccccccccccc, ccccccccccccc,\n"
@@ -969,6 +976,59 @@ TEST_F(FormatTestObjC, ObjCCxxKeywords) {
   verifyFormat("MACRO(new:)\n");
   verifyFormat("MACRO(delete:)\n");
   verifyFormat("foo = @{MACRO(new:) : MACRO(delete:)}\n");
+  verifyFormat("@implementation Foo\n"
+               "// Testing\n"
+               "- (Class)class {\n"
+               "}\n"
+               "- (void)foo {\n"
+               "}\n"
+               "@end\n");
+  verifyFormat("@implementation Foo\n"
+               "- (Class)class {\n"
+               "}\n"
+               "- (void)foo {\n"
+               "}\n"
+               "@end");
+  verifyFormat("@implementation Foo\n"
+               "+ (Class)class {\n"
+               "}\n"
+               "- (void)foo {\n"
+               "}\n"
+               "@end");
+  verifyFormat("@implementation Foo\n"
+               "- (Class)class:(Class)klass {\n"
+               "}\n"
+               "- (void)foo {\n"
+               "}\n"
+               "@end");
+  verifyFormat("@implementation Foo\n"
+               "+ (Class)class:(Class)klass {\n"
+               "}\n"
+               "- (void)foo {\n"
+               "}\n"
+               "@end");
+
+  verifyFormat("@interface Foo\n"
+               "// Testing\n"
+               "- (Class)class;\n"
+               "- (void)foo;\n"
+               "@end\n");
+  verifyFormat("@interface Foo\n"
+               "- (Class)class;\n"
+               "- (void)foo;\n"
+               "@end");
+  verifyFormat("@interface Foo\n"
+               "+ (Class)class;\n"
+               "- (void)foo;\n"
+               "@end");
+  verifyFormat("@interface Foo\n"
+               "- (Class)class:(Class)klass;\n"
+               "- (void)foo;\n"
+               "@end");
+  verifyFormat("@interface Foo\n"
+               "+ (Class)class:(Class)klass;\n"
+               "- (void)foo;\n"
+               "@end");
 }
 
 TEST_F(FormatTestObjC, ObjCLiterals) {