cmMakefile: Let AddDefinition accept a value as cm::string_view

This changes `cmMakefile::AddDefinition` to take a `cm::string_view` as value
argument instead of a `const char *`.

Benefits are:
- `std::string` can be passed to `cmMakefile::AddDefinition` directly without
  the `c_str()` plus string length recomputation fallback.
- Lengths of literals passed to `cmMakefile::AddDefinition` can be computed at
  compile time.

In various sources uses of `cmMakefile::AddDefinition` are adapted to avoid
`std::string::c_str` calls and the `std::string` is passed directly.
Uses of `cmMakefile::AddDefinition`, where a `nullptr` `const char*` might
be passed to `cmMakefile::AddDefinition` are extended with `nullptr` checks.

2 files changed, 15 insertions, 19 deletions

diff --git a/Source/CPack/cmCPackGenerator.cxx b/Source/CPack/cmCPackGenerator.cxx
index 350ebed..512ac7a 100644
--- a/Source/CPack/cmCPackGenerator.cxx
+++ b/Source/CPack/cmCPackGenerator.cxx
@@ -759,7 +759,7 @@ int cmCPackGenerator::InstallCMakeProject(
     if (this->GetOption("CPACK_INSTALL_PREFIX")) {
       dir += this->GetOption("CPACK_INSTALL_PREFIX");
     }
-    mf.AddDefinition("CMAKE_INSTALL_PREFIX", dir.c_str());
+    mf.AddDefinition("CMAKE_INSTALL_PREFIX", dir);
 
     cmCPackLogger(
       cmCPackLog::LOG_DEBUG,
@@ -799,7 +799,7 @@ int cmCPackGenerator::InstallCMakeProject(
       return 0;
     }
   } else {
-    mf.AddDefinition("CMAKE_INSTALL_PREFIX", tempInstallDirectory.c_str());
+    mf.AddDefinition("CMAKE_INSTALL_PREFIX", tempInstallDirectory);
 
     if (!cmsys::SystemTools::MakeDirectory(tempInstallDirectory,
                                            default_dir_mode)) {
@@ -818,11 +818,11 @@ int cmCPackGenerator::InstallCMakeProject(
   }
 
   if (!buildConfig.empty()) {
-    mf.AddDefinition("BUILD_TYPE", buildConfig.c_str());
+    mf.AddDefinition("BUILD_TYPE", buildConfig);
   }
   std::string installComponentLowerCase = cmSystemTools::LowerCase(component);
   if (installComponentLowerCase != "all") {
-    mf.AddDefinition("CMAKE_INSTALL_COMPONENT", component.c_str());
+    mf.AddDefinition("CMAKE_INSTALL_COMPONENT", component);
   }
 
   // strip on TRUE, ON, 1, one or several file names, but not on
@@ -863,9 +863,8 @@ int cmCPackGenerator::InstallCMakeProject(
   // forward definition of CMAKE_ABSOLUTE_DESTINATION_FILES
   // to CPack (may be used by generators like CPack RPM or DEB)
   // in order to transparently handle ABSOLUTE PATH
-  if (mf.GetDefinition("CMAKE_ABSOLUTE_DESTINATION_FILES")) {
-    mf.AddDefinition("CPACK_ABSOLUTE_DESTINATION_FILES",
-                     mf.GetDefinition("CMAKE_ABSOLUTE_DESTINATION_FILES"));
+  if (const char* def = mf.GetDefinition("CMAKE_ABSOLUTE_DESTINATION_FILES")) {
+    mf.AddDefinition("CPACK_ABSOLUTE_DESTINATION_FILES", def);
   }
 
   // Now rebuild the list of files after installation
diff --git a/Source/CPack/cpack.cxx b/Source/CPack/cpack.cxx
index c6018cf..89c3b1c 100644
--- a/Source/CPack/cpack.cxx
+++ b/Source/CPack/cpack.cxx
@@ -270,7 +270,7 @@ int main(int argc, char const* const* argv)
     }
 
     if (!cpackBuildConfig.empty()) {
-      globalMF.AddDefinition("CPACK_BUILD_CONFIG", cpackBuildConfig.c_str());
+      globalMF.AddDefinition("CPACK_BUILD_CONFIG", cpackBuildConfig);
     }
 
     if (cmSystemTools::FileExists(cpackConfigFile)) {
@@ -292,24 +292,21 @@ int main(int argc, char const* const* argv)
     }
 
     if (!generator.empty()) {
-      globalMF.AddDefinition("CPACK_GENERATOR", generator.c_str());
+      globalMF.AddDefinition("CPACK_GENERATOR", generator);
     }
     if (!cpackProjectName.empty()) {
-      globalMF.AddDefinition("CPACK_PACKAGE_NAME", cpackProjectName.c_str());
+      globalMF.AddDefinition("CPACK_PACKAGE_NAME", cpackProjectName);
     }
     if (!cpackProjectVersion.empty()) {
-      globalMF.AddDefinition("CPACK_PACKAGE_VERSION",
-                             cpackProjectVersion.c_str());
+      globalMF.AddDefinition("CPACK_PACKAGE_VERSION", cpackProjectVersion);
     }
     if (!cpackProjectVendor.empty()) {
-      globalMF.AddDefinition("CPACK_PACKAGE_VENDOR",
-                             cpackProjectVendor.c_str());
+      globalMF.AddDefinition("CPACK_PACKAGE_VENDOR", cpackProjectVendor);
     }
     // if this is not empty it has been set on the command line
     // go for it. Command line override values set in config file.
     if (!cpackProjectDirectory.empty()) {
-      globalMF.AddDefinition("CPACK_PACKAGE_DIRECTORY",
-                             cpackProjectDirectory.c_str());
+      globalMF.AddDefinition("CPACK_PACKAGE_DIRECTORY", cpackProjectDirectory);
     }
     // The value has not been set on the command line
     else {
@@ -318,11 +315,11 @@ int main(int argc, char const* const* argv)
       // use default value iff no value has been provided by the config file
       if (!globalMF.IsSet("CPACK_PACKAGE_DIRECTORY")) {
         globalMF.AddDefinition("CPACK_PACKAGE_DIRECTORY",
-                               cpackProjectDirectory.c_str());
+                               cpackProjectDirectory);
       }
     }
     for (auto const& cd : definitions.Map) {
-      globalMF.AddDefinition(cd.first, cd.second.c_str());
+      globalMF.AddDefinition(cd.first, cd.second);
     }
 
     const char* cpackModulesPath = globalMF.GetDefinition("CPACK_MODULE_PATH");
@@ -426,7 +423,7 @@ int main(int argc, char const* const* argv)
               std::ostringstream ostr;
               ostr << projVersionMajor << "." << projVersionMinor << "."
                    << projVersionPatch;
-              mf->AddDefinition("CPACK_PACKAGE_VERSION", ostr.str().c_str());
+              mf->AddDefinition("CPACK_PACKAGE_VERSION", ostr.str());
             }
 
             int res = cpackGenerator->DoPackage();