cmGlobalGenerator: Change parameter to string_view

Source/cmCoreTryCompile.cxx

@@ -575,7 +575,7 @@ cm::optional<cmTryCompileResult> cmCoreTryCompile::TryCompileCode(
     for (auto const& source : sources) {
       auto const& si = source.first;
       std::string ext = cmSystemTools::GetFilenameLastExtension(si);
-      std::string lang = gg->GetLanguageFromExtension(ext.c_str());
+      std::string lang = gg->GetLanguageFromExtension(ext);
       if (!lang.empty()) {
         testLangs.insert(lang);
       } else {

Source/cmGlobalGenerator.cxx

@@ -1100,17 +1100,18 @@ std::string cmGlobalGenerator::GetLanguageOutputExtension(
   return "";
 }
 
-std::string cmGlobalGenerator::GetLanguageFromExtension(char const* ext) const
+std::string cmGlobalGenerator::GetLanguageFromExtension(
+  cm::string_view ext) const
 {
   // if there is an extension and it starts with . then move past the
   // . because the extensions are not stored with a .  in the map
-  if (!ext) {
+  if (ext.empty()) {
     return "";
   }
-  if (*ext == '.') {
-    ++ext;
+  if (ext.front() == '.') {
+    ext = ext.substr(1);
   }
-  auto const it = this->ExtensionToLanguage.find(ext);
+  auto const it = this->ExtensionToLanguage.find(std::string(ext));
   if (it != this->ExtensionToLanguage.end()) {
     return it->second;
   }
@@ -1239,12 +1240,12 @@ std::string cmGlobalGenerator::GetSafeGlobalSetting(
   return this->Makefiles[0]->GetDefinition(name);
 }
 
-bool cmGlobalGenerator::IgnoreFile(char const* ext) const
+bool cmGlobalGenerator::IgnoreFile(cm::string_view ext) const
 {
   if (!this->GetLanguageFromExtension(ext).empty()) {
     return false;
   }
-  return (this->IgnoreExtensions.count(ext) > 0);
+  return (this->IgnoreExtensions.count(std::string(ext)) > 0);
 }
 
 bool cmGlobalGenerator::GetLanguageEnabled(std::string const& l) const

Source/cmGlobalGenerator.h

@@ -359,9 +359,9 @@ public:
   bool GetToolSupportsColor() const { return this->ToolSupportsColor; }
 
   //! return the language for the given extension
-  std::string GetLanguageFromExtension(char const* ext) const;
+  std::string GetLanguageFromExtension(cm::string_view ext) const;
   //! is an extension to be ignored
-  bool IgnoreFile(char const* ext) const;
+  bool IgnoreFile(cm::string_view ext) const;
   //! What is the preference for linkers and this language (None or Preferred)
   int GetLinkerPreference(std::string const& lang) const;
   //! What is the object file extension for a given source file?

Source/cmLocalVisualStudio7Generator.cxx

@@ -1487,7 +1487,7 @@ cmLocalVisualStudio7GeneratorFCInfo::cmLocalVisualStudio7GeneratorFCInfo(
     cmLVS7GFileConfig fc;
 
     std::string lang =
-      lg->GlobalGenerator->GetLanguageFromExtension(sf.GetExtension().c_str());
+      lg->GlobalGenerator->GetLanguageFromExtension(sf.GetExtension());
     std::string const& sourceLang = lg->GetSourceFileLanguage(sf);
     bool needForceLang = false;
     // source file does not match its extension language

Source/cmSourceFile.cxx

@@ -287,7 +287,7 @@ void cmSourceFile::CheckLanguage(std::string const& ext)
   // Try to identify the source file language from the extension.
   cmMakefile const* mf = this->Location.GetMakefile();
   cmGlobalGenerator* gg = mf->GetGlobalGenerator();
-  std::string l = gg->GetLanguageFromExtension(ext.c_str());
+  std::string l = gg->GetLanguageFromExtension(ext);
   if (!l.empty()) {
     this->Language = l;
   }

Source/cmSourceFileLocation.cxx

@@ -112,7 +112,7 @@ void cmSourceFileLocation::UpdateExtension(std::string const& name)
   cmGlobalGenerator* gg = this->Makefile->GetGlobalGenerator();
   cmMakefile const* mf = this->Makefile;
   auto* cm = mf->GetCMakeInstance();
-  if (!gg->GetLanguageFromExtension(ext.c_str()).empty() ||
+  if (!gg->GetLanguageFromExtension(ext).empty() ||
       cm->IsAKnownExtension(ext)) {
     // This is a known extension.  Use the given filename with extension.
     this->Name = cmSystemTools::GetFilenameName(name);

Source/cmVisualStudio10TargetGenerator.cxx

@@ -2835,9 +2835,8 @@ void cmVisualStudio10TargetGenerator::OutputSourceSpecificFlags(
   // Force language if the file extension does not match.
   // Note that MSVC treats the upper-case '.C' extension as C and not C++.
   std::string const ext = sf.GetExtension();
-  std::string const extLang = ext == "C"_s
-    ? "C"
-    : this->GlobalGenerator->GetLanguageFromExtension(ext.c_str());
+  std::string const extLang =
+    ext == "C"_s ? "C" : this->GlobalGenerator->GetLanguageFromExtension(ext);
   std::string lang = this->LocalGenerator->GetSourceFileLanguage(sf);
   char const* compileAs = nullptr;
   if (lang != extLang) {