cmSystemTools: Add GetComspec method to get cmd on Windows

The function attempts to read the path to cmd executable from the
COMSPEC environment variable. Falls back to cmd.exe if the respective
environment variable is not set or path doesn't exist.

3 files changed, 15 insertions, 7 deletions

diff --git a/Source/cmGlobalNinjaGenerator.cxx b/Source/cmGlobalNinjaGenerator.cxx
index 7d62fa8..b051d67 100644
--- a/Source/cmGlobalNinjaGenerator.cxx
+++ b/Source/cmGlobalNinjaGenerator.cxx
@@ -573,13 +573,7 @@ cmGlobalNinjaGenerator::cmGlobalNinjaGenerator(cmake* cm)
   cm->GetState()->SetWindowsShell(true);
 
   // Attempt to use full path to COMSPEC, default "cmd.exe"
-  std::string comspec;
-  if (cmSystemTools::GetEnv("COMSPEC", comspec) &&
-      cmSystemTools::FileIsFullPath(comspec)) {
-    this->Comspec = comspec;
-  } else {
-    this->Comspec = "cmd.exe";
-  }
+  this->Comspec = cmSystemTools::GetComspec();
 #endif
   cm->GetState()->SetNinja(true);
   this->FindMakeProgramFile = "CMakeNinjaFindMake.cmake";
diff --git a/Source/cmSystemTools.cxx b/Source/cmSystemTools.cxx
index 8e59a35..05cc85a 100644
--- a/Source/cmSystemTools.cxx
+++ b/Source/cmSystemTools.cxx
@@ -970,6 +970,17 @@ cmSystemTools::WindowsVersion cmSystemTools::GetWindowsVersion()
   result.dwBuildNumber = osviex.dwBuildNumber;
   return result;
 }
+
+std::string cmSystemTools::GetComspec()
+{
+  std::string comspec;
+  if (!cmSystemTools::GetEnv("COMSPEC", comspec) ||
+      !cmSystemTools::FileIsFullPath(comspec)) {
+    comspec = "cmd.exe";
+  }
+  return comspec;
+}
+
 #endif
 
 std::string cmSystemTools::GetRealPathResolvingWindowsSubst(
diff --git a/Source/cmSystemTools.h b/Source/cmSystemTools.h
index a07c749..d0b6046 100644
--- a/Source/cmSystemTools.h
+++ b/Source/cmSystemTools.h
@@ -585,6 +585,9 @@ public:
     unsigned int dwBuildNumber;
   };
   static WindowsVersion GetWindowsVersion();
+
+  /** Attempt to get full path to COMSPEC, default "cmd.exe" */
+  static std::string GetComspec();
 #endif
 
   /** Get the real path for a given path, removing all symlinks.