"New Class" wizard: Try to find a base class header

If the project has a header file whose name suggests that it might
declare the base class, then add an include statement for it.
While we cannot guarantee that the include statement is resolvable as-
is, it's at least a basis for the user to adapt accordingly, while
without any include statement the class will definitely not compile.

Fixes: QTCREATORBUG-3855
Change-Id: I55ec43d58a9a13b9b59a5bbe6415a457b974b654
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

1 files changed, 69 insertions, 0 deletions

diff --git a/src/plugins/cpptools/cpptoolsjsextension.cpp b/src/plugins/cpptools/cpptoolsjsextension.cpp
index 4c283fc644f..03a0d3df99d 100644
--- a/src/plugins/cpptools/cpptoolsjsextension.cpp
+++ b/src/plugins/cpptools/cpptoolsjsextension.cpp
@@ -29,10 +29,15 @@
 
 #include <coreplugin/icore.h>
 
+#include <projectexplorer/project.h>
+#include <projectexplorer/projectnodes.h>
+#include <projectexplorer/session.h>
+
 #include <utils/codegeneration.h>
 #include <utils/fileutils.h>
 
 #include <QFileInfo>
+#include <QStringList>
 #include <QTextStream>
 
 namespace CppTools {
@@ -113,5 +118,69 @@ QString CppToolsJsExtension::closeNamespaces(const QString &klass) const
     return result;
 }
 
+QString CppToolsJsExtension::includeStatement(
+        const QString &fullyQualifiedClassName,
+        const QString &suffix,
+        const QString &specialClasses,
+        const QString &pathOfIncludingFile
+        )
+{
+    if (fullyQualifiedClassName.isEmpty())
+        return {};
+    const QString className = parts(fullyQualifiedClassName).last();
+    if (className.isEmpty() || specialClasses.contains(className))
+        return {};
+    if (className.startsWith('Q') && className.length() > 2 && className.at(1).isUpper())
+        return "#include <" + className + ">\n";
+    const auto withUnderScores = [&className] {
+        QString baseName = className;
+        baseName[0] = baseName[0].toLower();
+        for (int i = 1; i < baseName.length(); ++i) {
+            if (baseName[i].isUpper()) {
+                baseName.insert(i, '_');
+                baseName[i + 1] = baseName[i + 1].toLower();
+                ++i;
+            }
+        }
+        return baseName;
+    };
+    QStringList candidates{className + '.' + suffix};
+    bool hasUpperCase = false;
+    bool hasLowerCase = false;
+    for (int i = 0; i < className.length() && (!hasUpperCase || !hasLowerCase); ++i) {
+        if (className.at(i).isUpper())
+            hasUpperCase = true;
+        if (className.at(i).isLower())
+            hasLowerCase = true;
+    }
+    if (hasUpperCase)
+        candidates << className.toLower() + '.' + suffix;
+    if (hasUpperCase && hasLowerCase)
+        candidates << withUnderScores()  + '.' + suffix;
+    candidates.removeDuplicates();
+    using namespace ProjectExplorer;
+    const auto nodeMatchesFileName = [&candidates](Node *n) {
+        if (const FileNode * const fileNode = n->asFileNode()) {
+            if (fileNode->fileType() == FileType::Header
+                && candidates.contains(fileNode->filePath().fileName())) {
+                return true;
+            }
+        }
+        return false;
+    };
+    for (const Project * const p : SessionManager::projects()) {
+        const Node *theNode = p->rootProjectNode()->findNode(nodeMatchesFileName);
+        if (theNode) {
+            const bool sameDir = pathOfIncludingFile == theNode->filePath().toFileInfo().path();
+            return QString("#include ")
+                    .append(sameDir ? '"' : '<')
+                    .append(theNode->filePath().fileName())
+                    .append(sameDir ? '"' : '>')
+                    .append('\n');
+        }
+    }
+    return {};
+}
+
 } // namespace Internal
 } // namespace CppTools