objc - Simplify switing objc decl context by using

a context switching object.

llvm-svn: 138248

clang/include/clang/Parse/Parser.h

@@ -503,6 +503,23 @@ private:
     }
   };
 
+  /// ObjCDeclContextSwitch - An object used to switch context from
+  /// an objective-c decl context to its enclosing decl context and
+  /// back.
+  class ObjCDeclContextSwitch {
+    Parser &P;
+    Decl *DC;
+  public:
+    explicit ObjCDeclContextSwitch(Parser &p) : P(p), 
+               DC(p.getObjCDeclContext()) {
+      if (DC)
+        P.Actions.ActOnObjCContainerFinishDefinition(DC);
+    }
+    ~ObjCDeclContextSwitch() {
+      if (DC)
+        P.Actions.ActOnObjCContainerStartDefinition(DC);
+    }
+  };
 
   SourceLocation MatchRHSPunctuation(tok::TokenKind RHSTok,
                                      SourceLocation LHSLoc);

clang/lib/Parse/ParseDeclCXX.cpp

@@ -52,9 +52,7 @@ Decl *Parser::ParseNamespace(unsigned Context,
                              SourceLocation InlineLoc) {
   assert(Tok.is(tok::kw_namespace) && "Not a namespace!");
   SourceLocation NamespaceLoc = ConsumeToken();  // eat the 'namespace'.
-  Decl *DC = getObjCDeclContext();
-  if (DC)
-    Actions.ActOnObjCContainerFinishDefinition(DC);
+  ObjCDeclContextSwitch ObjCDC(*this);
     
   if (Tok.is(tok::code_completion)) {
     Actions.CodeCompleteNamespaceDecl(getCurScope());
@@ -92,10 +90,7 @@ Decl *Parser::ParseNamespace(unsigned Context,
     if (InlineLoc.isValid())
       Diag(InlineLoc, diag::err_inline_namespace_alias)
           << FixItHint::CreateRemoval(InlineLoc);
-    Decl *Res = ParseNamespaceAlias(NamespaceLoc, IdentLoc, Ident, DeclEnd);
-    if (DC)
-      Actions.ActOnObjCContainerStartDefinition(DC);
-    return Res;
+    return ParseNamespaceAlias(NamespaceLoc, IdentLoc, Ident, DeclEnd);
   }
 
 
@@ -106,8 +101,6 @@ Decl *Parser::ParseNamespace(unsigned Context,
     }
     Diag(Tok, Ident ? diag::err_expected_lbrace :
          diag::err_expected_ident_lbrace);
-    if (DC)
-      Actions.ActOnObjCContainerStartDefinition(DC);
     return 0;
   }
 
@@ -122,8 +115,6 @@ Decl *Parser::ParseNamespace(unsigned Context,
     }
     Diag(LBrace, diag::err_namespace_nonnamespace_scope);
     SkipUntil(tok::r_brace, false);
-    if (DC)
-      Actions.ActOnObjCContainerStartDefinition(DC);
     return 0;
   }
 
@@ -182,8 +173,6 @@ Decl *Parser::ParseNamespace(unsigned Context,
   Actions.ActOnFinishNamespaceDef(NamespcDecl, RBraceLoc);
 
   DeclEnd = RBraceLoc;
-  if (DC)
-    Actions.ActOnObjCContainerStartDefinition(DC);
   return NamespcDecl;
 }
 
@@ -328,9 +317,8 @@ Decl *Parser::ParseUsingDirectiveOrDeclaration(unsigned Context,
                                              ParsedAttributesWithRange &attrs,
                                                Decl **OwnedType) {
   assert(Tok.is(tok::kw_using) && "Not using token");
-  Decl *DC = getObjCDeclContext();
-  if (DC)
-    Actions.ActOnObjCContainerFinishDefinition(DC);
+  ObjCDeclContextSwitch ObjCDC(*this);
+  
   // Eat 'using'.
   SourceLocation UsingLoc = ConsumeToken();
 
@@ -348,10 +336,7 @@ Decl *Parser::ParseUsingDirectiveOrDeclaration(unsigned Context,
         << R << FixItHint::CreateRemoval(R);
     }
 
-    Decl *Res = ParseUsingDirective(Context, UsingLoc, DeclEnd, attrs);
-    if (DC)
-      Actions.ActOnObjCContainerStartDefinition(DC);
-    return Res;
+    return ParseUsingDirective(Context, UsingLoc, DeclEnd, attrs);
   }
 
   // Otherwise, it must be a using-declaration or an alias-declaration.
@@ -359,11 +344,8 @@ Decl *Parser::ParseUsingDirectiveOrDeclaration(unsigned Context,
   // Using declarations can't have attributes.
   ProhibitAttributes(attrs);
 
-  Decl *Res = ParseUsingDeclaration(Context, TemplateInfo, UsingLoc, DeclEnd,
+  return ParseUsingDeclaration(Context, TemplateInfo, UsingLoc, DeclEnd,
                                     AS_none, OwnedType);
-  if (DC)
-    Actions.ActOnObjCContainerStartDefinition(DC);
-  return Res;
 }
 
 /// ParseUsingDirective - Parse C++ using-directive, assumes

clang/lib/Parse/ParseObjc.cpp

@@ -776,9 +776,8 @@ ParsedType Parser::ParseObjCTypeName(ObjCDeclSpec &DS,
 
   SourceLocation LParenLoc = ConsumeParen();
   SourceLocation TypeStartLoc = Tok.getLocation();
-  Decl *DC = getObjCDeclContext();
-  if (DC)
-    Actions.ActOnObjCContainerFinishDefinition(DC);
+  ObjCDeclContextSwitch ObjCDC(*this);
+
   // Parse type qualifiers, in, inout, etc.
   ParseObjCTypeQualifierList(DS, Context);
 
@@ -801,8 +800,6 @@ ParsedType Parser::ParseObjCTypeName(ObjCDeclSpec &DS,
     // place.  Emit an error then return what we have as the type.
     MatchRHSPunctuation(tok::r_paren, LParenLoc);
   }
-  if (DC)
-    Actions.ActOnObjCContainerStartDefinition(DC);
   return Ty;
 }
 

clang/lib/Parse/ParseTemplate.cpp

@@ -27,20 +27,13 @@ Decl *
 Parser::ParseDeclarationStartingWithTemplate(unsigned Context,
                                              SourceLocation &DeclEnd,
                                              AccessSpecifier AS) {
-  Decl *DC = getObjCDeclContext();
-  if (DC)
-    Actions.ActOnObjCContainerFinishDefinition(DC);
+  ObjCDeclContextSwitch ObjCDC(*this);
+  
   if (Tok.is(tok::kw_template) && NextToken().isNot(tok::less)) {
-    Decl *Res = ParseExplicitInstantiation(SourceLocation(), ConsumeToken(),
+    return ParseExplicitInstantiation(SourceLocation(), ConsumeToken(),
                                            DeclEnd);
-    if (DC)
-      Actions.ActOnObjCContainerStartDefinition(DC);
-    return Res;
   }
-  Decl *Res = ParseTemplateDeclarationOrSpecialization(Context, DeclEnd, AS);
-  if (DC)
-    Actions.ActOnObjCContainerStartDefinition(DC);
-  return Res;
+  return ParseTemplateDeclarationOrSpecialization(Context, DeclEnd, AS);
 }
 
 /// \brief RAII class that manages the template parameter depth.

clang/lib/Parse/Parser.cpp

@@ -811,16 +811,12 @@ Parser::ParseDeclarationOrFunctionDefinition(ParsedAttributes &attrs,
                                              AccessSpecifier AS) {
   ParsingDeclSpec DS(*this);
   DS.takeAttributesFrom(attrs);
-  Decl *DC = getObjCDeclContext();
-  if (DC)
-    // Must temporarily exit the objective-c container scope for
-    // parsing c constructs and re-enter objc container scope
-    // afterwards.
-    Actions.ActOnObjCContainerFinishDefinition(DC);
-  DeclGroupPtrTy resPtrTy =  ParseDeclarationOrFunctionDefinition(DS, AS);
-  if (DC)
-    Actions.ActOnObjCContainerStartDefinition(DC);
-  return resPtrTy;
+  // Must temporarily exit the objective-c container scope for
+  // parsing c constructs and re-enter objc container scope
+  // afterwards.
+  ObjCDeclContextSwitch ObjCDC(*this);
+    
+  return ParseDeclarationOrFunctionDefinition(DS, AS);
 }
 
 /// ParseFunctionDefinition - We parsed and verified that the specified