CMake: Improve handling of source_groups

* Use a special icon for source groups, so that those can get
  destinguished from folders
* Simplify folder structure below source groups to not include
  common paths elements

Task-number: QTCREATORBUG-23372
Change-Id: Ifcb35af9b35805a6272f27b0801c2fe7dfce95ae
Reviewed-by: Cristian Adam <cristian.adam@qt.io>

src/plugins/cmakeprojectmanager/fileapidataextractor.cpp

@@ -33,6 +33,7 @@
 #include <utils/algorithm.h>
 #include <utils/qtcassert.h>
 #include <utils/qtcprocess.h>
+#include <utils/utilsicons.h>
 
 #include <QDir>
 
@@ -395,31 +396,19 @@ void addProjects(const QHash<Utils::FilePath, ProjectNode *> &cmakeListsNodes,
     }
 }
 
-QVector<FolderNode *> addSourceGroups(ProjectNode *targetRoot,
+std::unique_ptr<FolderNode> createSourceGroupNode(const QString &sourceGroupName,
-                                      const TargetDetails &td,
                                                   const FilePath &sourceDirectory)
 {
-    QVector<FolderNode *> sourceGroupNodes;
+    if (sourceGroupName.isEmpty())
-    if (td.sourceGroups.size() == 1) {
+        return {};
-        sourceGroupNodes.append(
+
-            targetRoot); // Only one source group, so do not bother to display any:-)
-    } else {
-        for (const QString &sg : td.sourceGroups) {
-            if (sg.isEmpty()) {
-                sourceGroupNodes.append(targetRoot);
-            } else {
     auto sgNode = createCMakeVFolder(sourceDirectory,
                                      Node::DefaultFolderPriority + 5,
-                                                 sg);
+                                     sourceGroupName);
+
     sgNode->setListInProject(false);
-
+    sgNode->setIcon(QIcon::fromTheme("edit-copy", ::Utils::Icons::COPY.icon()));
-                sourceGroupNodes.append(sgNode.get());
+    return sgNode;
-                targetRoot->addNode(std::move(sgNode));
-            }
-        }
-    }
-
-    return sourceGroupNodes;
 }
 
 void addCompileGroups(ProjectNode *targetRoot,
@@ -439,11 +428,11 @@ void addCompileGroups(ProjectNode *targetRoot,
     targetRoot->forEachGenericNode(
         [&alreadyListed](const Node *n) { alreadyListed.insert(n->filePath()); });
 
-    QVector<FolderNode *> sourceGroupNodes = addSourceGroups(targetRoot, td, sourceDirectory);
     const QDir topSourceDir(topSourceDirectory.toString());
 
     std::vector<std::unique_ptr<FileNode>> buildFileNodes;
     std::vector<std::unique_ptr<FileNode>> otherFileNodes;
+    std::vector<std::vector<std::unique_ptr<FileNode>>> sourceGroupFileNodes{td.sourceGroups.size()};
 
     for (const SourceInfo &si : td.sources) {
         const FilePath sourcePath = FilePath::fromString(
@@ -467,12 +456,34 @@ void addCompileGroups(ProjectNode *targetRoot,
         if (sourcePath.isChildOf(buildDirectory) && !inSourceBuild) {
             buildFileNodes.emplace_back(std::move(node));
         } else if (sourcePath.isChildOf(sourceDirectory)) {
-            sourceGroupNodes[si.sourceGroup]->addNestedNode(std::move(node));
+            sourceGroupFileNodes[si.sourceGroup].emplace_back(std::move(node));
         } else {
             otherFileNodes.emplace_back(std::move(node));
         }
     }
 
+    // Calculate base directory for source groups:
+    for (size_t i = 0; i < sourceGroupFileNodes.size(); ++i) {
+        std::vector<std::unique_ptr<FileNode>> &current = sourceGroupFileNodes[i];
+        FilePath baseDirectory;
+        // All the sourceGroupFileNodes are below sourceDirectory, so this is safe:
+        for (const std::unique_ptr<FileNode> &fn : current) {
+            if (baseDirectory.isEmpty()) {
+                baseDirectory = fn->filePath().parentDir();
+            } else {
+                baseDirectory = Utils::FileUtils::commonPath(baseDirectory, fn->filePath());
+            }
+        }
+
+        FolderNode *insertNode = targetRoot;
+        if (auto sgNode = createSourceGroupNode(td.sourceGroups[i], baseDirectory)) {
+            insertNode = sgNode.get();
+            targetRoot->addNode(std::move(sgNode));
+        }
+
+        insertNode->addNestedNodes(std::move(sourceGroupFileNodes[i]));
+    }
+
     addCMakeVFolder(targetRoot,
                     buildDirectory,
                     100,