New loplugin:external

...warning about (for now only) functions and variables with external linkage
that likely don't need it.

The problems with moving entities into unnamed namespacs and breaking ADL
(as alluded to in comments in compilerplugins/clang/external.cxx) are
illustrated by the fact that while

  struct S1 { int f() { return 0; } };
  int f(S1 s) { return s.f(); }
  namespace N {
    struct S2: S1 { int f() { return 1; } };
    int f(S2 s) { return s.f(); }
  }
  int main() { return f(N::S2()); }

returns 1, both moving just the struct S2 into an nunnamed namespace,

  struct S1 { int f() { return 0; } };
  int f(S1 s) { return s.f(); }
  namespace N {
    namespace { struct S2: S1 { int f() { return 1; } }; }
    int f(S2 s) { return s.f(); }
  }
  int main() { return f(N::S2()); }

as well as moving just the function f overload into an unnamed namespace,

  struct S1 { int f() { return 0; } };
  int f(S1 s) { return s.f(); }
  namespace N {
    struct S2: S1 { int f() { return 1; } };
    namespace { int f(S2 s) { return s.f(); } }
  }
  int main() { return f(N::S2()); }

would each change the program to return 0 instead.

Change-Id: I4d09f7ac5e8f9bcd6e6bde4712608444b642265c
Reviewed-on: https://gerrit.libreoffice.org/60539
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

2 files changed, 9 insertions, 5 deletions

diff --git a/xmlhelp/source/cxxhelp/provider/databases.cxx b/xmlhelp/source/cxxhelp/provider/databases.cxx
index 88cedb7bfefd..2ab99629f3df 100644
--- a/xmlhelp/source/cxxhelp/provider/databases.cxx
+++ b/xmlhelp/source/cxxhelp/provider/databases.cxx
@@ -1316,7 +1316,7 @@ OUString ExtensionIteratorBase::implGetFileFromPackage(
     return aFile;
 }
 
-inline bool isLetter( sal_Unicode c )
+static inline bool isLetter( sal_Unicode c )
 {
     return rtl::isAsciiAlpha(c);
 }
diff --git a/xmlhelp/source/treeview/tvread.cxx b/xmlhelp/source/treeview/tvread.cxx
index c8006bee590f..1035cdd9c3aa 100644
--- a/xmlhelp/source/treeview/tvread.cxx
+++ b/xmlhelp/source/treeview/tvread.cxx
@@ -320,7 +320,9 @@ TVRead::hasByHierarchicalName( const OUString& aName )
 /*                                                                        */
 /**************************************************************************/
 
-extern "C" void start_handler(void *userData,
+extern "C" {
+
+static void start_handler(void *userData,
                    const XML_Char *name,
                    const XML_Char **atts)
 {
@@ -357,14 +359,14 @@ extern "C" void start_handler(void *userData,
     }
 }
 
-extern "C" void end_handler(void *userData,
+static void end_handler(void *userData,
                  SAL_UNUSED_PARAMETER const XML_Char * )
 {
     TVDom **tvDom = static_cast< TVDom** >( userData );
     *tvDom = (*tvDom)->getParent();
 }
 
-extern "C" void data_handler( void *userData,
+static void data_handler( void *userData,
                    const XML_Char *s,
                    int len)
 {
@@ -373,6 +375,8 @@ extern "C" void data_handler( void *userData,
         (*tvDom)->setTitle( s,len );
 }
 
+}
+
 TVChildTarget::TVChildTarget( const ConfigData& configData,TVDom* tvDom )
 {
     Elements.resize( tvDom->children.size() );
@@ -1011,7 +1015,7 @@ Reference< deployment::XPackage > ExtensionIteratorBase::implGetNextBundledHelpP
     return xHelpPackage;
 }
 
-inline bool isLetter( sal_Unicode c )
+static inline bool isLetter( sal_Unicode c )
 {
     return rtl::isAsciiAlpha(c);
 }