Add FOLDER target property, for IDEs (#3796)

This work was started from a patch by Thomas Schiffer.
Thanks, Thomas!

See the newly added documentation of the FOLDER target
property for details.

Also added global properties, USE_FOLDERS and
PREDEFINED_TARGETS_FOLDER. See new docs here, too.

By default, the FOLDER target property is used to organize
targets into folders in IDEs that have support for such
organization.

This commit adds "solution folder" support to the Visual
Studio generators. Currently works with versions 7 through
10.

Also, use the new FOLDER property in the ExternalProject
test and in the CMake project itself.

1 files changed, 40 insertions, 0 deletions

diff --git a/Source/cmGlobalGenerator.cxx b/Source/cmGlobalGenerator.cxx
index bd26b5f..8e77294 100644
--- a/Source/cmGlobalGenerator.cxx
+++ b/Source/cmGlobalGenerator.cxx
@@ -1837,6 +1837,38 @@ void cmGlobalGenerator::CreateDefaultGlobalTargets(cmTargets* targets)
     }
 }
 
+//----------------------------------------------------------------------------
+const char* cmGlobalGenerator::GetPredefinedTargetsFolder()
+{
+  const char* prop =
+    this->GetCMakeInstance()->GetProperty("PREDEFINED_TARGETS_FOLDER");
+
+  if (prop)
+    {
+    return prop;
+    }
+
+  return "CMakePredefinedTargets";
+}
+
+//----------------------------------------------------------------------------
+bool cmGlobalGenerator::UseFolderProperty()
+{
+  const char* prop = this->GetCMakeInstance()->GetProperty("USE_FOLDERS");
+
+  // If this property is defined, let the setter turn this on or off...
+  //
+  if (prop)
+    {
+    return cmSystemTools::IsOn(prop);
+    }
+
+  // By default, this feature is ON:
+  //
+  return true;
+}
+
+//----------------------------------------------------------------------------
 cmTarget cmGlobalGenerator::CreateGlobalTarget(
   const char* name, const char* message,
   const cmCustomCommandLines* commandLines,
@@ -1866,6 +1898,14 @@ cmTarget cmGlobalGenerator::CreateGlobalTarget(
     {
     target.AddUtility(dit->c_str());
     }
+
+  // Organize in the "predefined targets" folder:
+  //
+  if (this->UseFolderProperty())
+    {
+    target.SetProperty("FOLDER", this->GetPredefinedTargetsFolder());
+    }
+
   return target;
 }