New simplification: Remove 'extern "C"' from C++ code.

Refactorization in cppcheck.cpp: Catch exception as const reference instead of non-const reference.

lib/cppcheck.cpp

@@ -225,7 +225,7 @@ unsigned int CppCheck::processFile(const std::string& filename)
 
             ++checkCount;
         }
-    } catch (std::runtime_error &e) {
+    } catch (const std::runtime_error &e) {
         // Exception was thrown when checking this file..
         const std::string fixedpath = Path::toNativeSeparators(filename);
         _errorLogger.reportOut("Bailing out from checking " + fixedpath + ": " + e.what());

lib/tokenize.cpp

@@ -1977,6 +1977,10 @@ bool Tokenizer::tokenize(std::istream &code,
     // combine "- %num%"
     concatenateNegativeNumber();
 
+    // remove extern "C" and extern "C" {}
+    if (isCPP())
+        simplifyExternC();
+
     // simplify weird but legal code: "[;{}] ( { code; } ) ;"->"[;{}] code;"
     simplifyRoundCurlyParenthesis();
 
@@ -2451,6 +2455,20 @@ void Tokenizer::concatenateNegativeNumber()
     }
 }
 
+void Tokenizer::simplifyExternC()
+{
+    for (Token *tok = _tokens; tok; tok = tok->next()) {
+        if (Token::Match(tok, "extern \"C\" {|")) {
+            if (tok->strAt(2) == "{") {
+                tok->linkAt(2)->deleteThis();
+                tok->deleteNext(2);
+            } else
+                tok->deleteNext();
+            tok->deleteThis();
+        }
+    }
+}
+
 void Tokenizer::simplifyRoundCurlyParenthesis()
 {
     for (Token *tok = _tokens; tok; tok = tok->next()) {

lib/tokenize.h

@@ -489,6 +489,8 @@ public:
 
     void concatenateNegativeNumber();
 
+    void simplifyExternC();
+
     void simplifyRoundCurlyParenthesis();
 
     void simplifyDebugNew();

test/testtokenize.cpp

@@ -161,6 +161,7 @@ private:
         TEST_CASE(simplifyKnownVariablesBailOutSwitchBreak); // ticket #2324
         TEST_CASE(simplifyKnownVariablesFloat);    // #2454 - float variable
         TEST_CASE(simplifyKnownVariablesClassMember);  // #2815 - value of class member may be changed by function call
+        TEST_CASE(simplifyExternC);
 
         TEST_CASE(varid1);
         TEST_CASE(varid2);
@@ -2508,6 +2509,10 @@ private:
         }
     }
 
+    void simplifyExternC() {
+        ASSERT_EQUALS("int foo ( ) ;", tokenizeAndStringify("extern \"C\" int foo();"));
+        ASSERT_EQUALS("int foo ( ) ;", tokenizeAndStringify("extern \"C\" { int foo(); }"));
+    }
 
 
     std::string tokenizeDebugListing(const std::string &code, bool simplify = false, const char filename[] = "test.cpp") {
@@ -3222,7 +3227,7 @@ private:
     void varid40() {
         const std::string code("extern \"C\" int (*a())();");
         ASSERT_EQUALS("\n\n##file 0\n"
-                      "1: extern \"C\" int ( * a ( ) ) ( ) ;\n",
+                      "1: int ( * a ( ) ) ( ) ;\n",
                       tokenizeDebugListing(code));
     }