Bug 382746 - Adding C/C++ nature for C Project impossible

This patch modifies the wizard so that the C projects also show in the
list of projects.
- If a given C project is selected and the C nature is selected, the
project is not modified.
- If a given C project is selected and the C++ nature is selected, the
C++ nature is added and project type and toolchain selection have no
effect because it is assumed that the project type and toolchain had
already been setup before hand.
- Old-style projects (CDT 3.0) are not converted anymore.
Unchanged behavior:
- C++ projects never show in the list of projects. Removing nature is
(still) unsupported.
- Non-CDT project behave as they use to.

Change-Id: Ie6282c11d90c42d21ecad2996ab49ebd64c38ece
Signed-off-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>

build/org.eclipse.cdt.make.ui/src/org/eclipse/cdt/make/internal/ui/MakeResources.properties

@@ -1,5 +1,5 @@
 ###############################################################################
-# Copyright (c) 2003, 2010 QNX Software Systems and others.
+# Copyright (c) 2003, 2015 QNX Software Systems and others.
 # All rights reserved. This program and the accompanying materials
 # are made available under the terms of the Eclipse Public License v1.0
 # which accompanies this distribution, and is available at
@@ -46,7 +46,7 @@ MakeCCWizardSettings.title=C++/Make Project Settings
 MakeCCWizardSettings.description=Define the project and 'make' builder settings
 
 WizardMakeProjectConversion.title=Convert to a C/C++ project
-WizardMakeProjectConversion.description=The wizard adds C/C++ Nature to the selected projects to enable C/C++ Tools Support for them. It also converts old-style C/C++ projects to the new style.
+WizardMakeProjectConversion.description=The wizard adds C/C++ Nature to the selected projects to enable C/C++ Tools Support for them.
 WizardMakeProjectConversion.monitor.convertingToMakeProject=Converting to C/C++ Project...
 WizardMakeProjectConversion.projectOptions.title=Project options
 WizardMakeProjectConversion.projectOptions.projectType=Specify project type

build/org.eclipse.cdt.managedbuilder.ui/plugin.xml

@@ -351,7 +351,7 @@
 		            <adapt type="org.eclipse.core.resources.IProject" >
 		               <test
 		                     property="org.eclipse.core.resources.projectNature"
-		                     value="org.eclipse.cdt.core.cnature"/>
+		                     value="org.eclipse.cdt.core.ccnature"/>
 		            </adapt>
 				</not>
 		 	</and>

build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/wizards/ConvertToMakeWizardPage.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2013 QNX Software Systems and others.
+ * Copyright (c) 2000, 2015 QNX Software Systems and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -9,6 +9,7 @@
  *     QNX Software Systems - Initial API and implementation
  *     Intel corporation    - customization for New Project model.
  *     Marc-Andre Laperle (Ericsson) - Bug 394492 Project options not visible
+ *     Marc-Andre Laperle (Ericsson) - Bug 382746 Add C++ nature to C Project
  *******************************************************************************/
 package org.eclipse.cdt.managedbuilder.ui.wizards;
 
@@ -16,8 +17,8 @@ package org.eclipse.cdt.managedbuilder.ui.wizards;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.eclipse.cdt.core.CCProjectNature;
 import org.eclipse.cdt.make.internal.ui.MakeUIPlugin;
-import org.eclipse.cdt.managedbuilder.core.ManagedBuilderCorePlugin;
 import org.eclipse.cdt.ui.newui.AbstractPage;
 import org.eclipse.cdt.ui.newui.CDTPrefUtil;
 import org.eclipse.cdt.ui.newui.PageLayout;
@@ -250,29 +251,29 @@ public class ConvertToMakeWizardPage extends ConvertProjectWizardPage {
     /**
      * Method isCandidate returns true for:
      * - non-CDT projects
-     * - old style Make CDT projects
+     * - C projects, to be potentially converted to C++
-     * So new model projects and
-     * old style managed projects
-     * are refused.
      */
     @Override
 	public boolean isCandidate(IProject project) {
-    	boolean a = !AbstractPage.isCDTPrj(project);
+		boolean isCDTProject = AbstractPage.isCDTPrj(project);
-    	boolean b = ManagedBuilderCorePlugin.getDefault().isOldStyleMakeProject(project);
+		boolean cOnly = false;
-		return a || b;
+		try {
+			cOnly = !project.hasNature(CCProjectNature.CC_NATURE_ID);
+		} catch (CoreException e) {
+			// If the project doesn't exist or is not open, it cannot be converted
+			return false;
+		}
+		return !isCDTProject || cOnly;
     }
 
     @Override
 	public void convertProject(IProject project, String bsId, IProgressMonitor monitor) throws CoreException{
 		monitor.beginTask(MakeUIPlugin.getResourceString("WizardMakeProjectConversion.monitor.convertingToMakeProject"), 3); //$NON-NLS-1$
 		try {
-			if (ManagedBuilderCorePlugin.getDefault().isOldStyleMakeProject(project)) {
+			boolean wasCDTProject = AbstractPage.isCDTPrj(project);
-				ManagedBuilderCorePlugin.getDefault().convertOldStdMakeToNewStyle(project, monitor);
+			super.convertProject(project, bsId, new SubProgressMonitor(monitor, 1));
-			} else {
+			if (!wasCDTProject && isSetProjectType()) {
-				super.convertProject(project, bsId, new SubProgressMonitor(monitor, 1));
+				h_selected.convertProject(project, monitor);
-				if (isSetProjectType()) {
-					h_selected.convertProject(project, monitor);
-				}
 			}
 		} finally {
 			monitor.done();
@@ -283,13 +284,10 @@ public class ConvertToMakeWizardPage extends ConvertProjectWizardPage {
 	public void convertProject(IProject project, IProgressMonitor monitor, String projectID) throws CoreException {
 		monitor.beginTask(MakeUIPlugin.getResourceString("WizardMakeProjectConversion.monitor.convertingToMakeProject"), 3); //$NON-NLS-1$
 		try {
-			if (ManagedBuilderCorePlugin.getDefault().isOldStyleMakeProject(project)) {
+			boolean wasCDTProject = AbstractPage.isCDTPrj(project);
-				ManagedBuilderCorePlugin.getDefault().convertOldStdMakeToNewStyle(project, monitor);
+			super.convertProject(project, new SubProgressMonitor(monitor, 1), projectID);
-			} else {
+			if (!wasCDTProject && isSetProjectType()) {
-				super.convertProject(project, new SubProgressMonitor(monitor, 1), projectID);
+				h_selected.convertProject(project, monitor);
-				if (isSetProjectType()) {
-					h_selected.convertProject(project, monitor);
-				}
 			}
 		} finally {
 			monitor.done();