Clang: implement findUsages with existing index

Functionality is limited to the abilities of
current index which is not updated and is
generated only at project open.
Search box temporarily doesn't allow to "Search again".

Change-Id: Id1047f27ad0aafc901f06aa51ad38ceab95eaebb
Reviewed-by: Marco Bubke <marco.bubke@qt.io>
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

src/plugins/cppeditor/cppeditorwidget.cpp

@@ -44,6 +44,7 @@
 #include <coreplugin/actionmanager/actionmanager.h>
 #include <coreplugin/editormanager/documentmodel.h>
 #include <coreplugin/editormanager/editormanager.h>
+#include <coreplugin/find/searchresultwindow.h>
 #include <coreplugin/infobar.h>
 
 #include <cpptools/cppcanonicalsymbol.h>
@@ -344,23 +345,73 @@ void CppEditorWidget::onShowInfoBarAction(const Id &id, bool show)
     action->setVisible(show);
 }
 
+static QString getDocumentLine(const QTextDocument &document, int line)
+{
+    return document.findBlockByNumber(line - 1).text();
+}
+
+static QString getFileLine(const QString &path, int line)
+{
+    const IDocument *document = DocumentModel::documentForFilePath(path);
+    const TextDocument *textDocument = qobject_cast<const TextDocument *>(document);
+    if (textDocument)
+        return getDocumentLine(*textDocument->document(), line);
+
+    const QTextCodec *defaultCodec = Core::EditorManager::defaultTextCodec();
+    QString contents;
+    Utils::TextFileFormat format;
+    QString error;
+    if (Utils::TextFileFormat::readFile(path, defaultCodec, &contents, &format, &error)
+            != Utils::TextFileFormat::ReadSuccess) {
+        qWarning() << "Error reading file " << path << " : " << error;
+        return QString();
+    }
+
+    const QTextDocument tmpDocument{contents};
+    return getDocumentLine(tmpDocument, line);
+}
+
+static void findRenameCallback(QTextCursor cursor,
+                               const CppTools::Usages &usages,
+                               bool rename = false)
+{
+    cursor = Utils::Text::wordStartCursor(cursor);
+    cursor.movePosition(QTextCursor::EndOfWord, QTextCursor::KeepAnchor);
+    QString text = cursor.selectedText();
+    SearchResultWindow::SearchMode mode = SearchResultWindow::SearchOnly;
+    if (rename)
+        mode = SearchResultWindow::SearchAndReplace;
+    SearchResult *search = SearchResultWindow::instance()->startNewSearch(
+                QObject::tr("C++ Usages:"),
+                QString(),
+                text,
+                mode,
+                SearchResultWindow::PreserveCaseDisabled,
+                QLatin1String("CppEditor"));
+    for (const CppTools::Usage &usage : usages) {
+        const QString lineStr = getFileLine(usage.path, usage.line);
+        if (lineStr.isEmpty())
+            continue;
+        Search::TextRange range{Search::TextPosition(usage.line, usage.column - 1),
+                    Search::TextPosition(usage.line, usage.column + text.length() - 1)};
+        search->addResult(usage.path, lineStr, range);
+    }
+    search->finishSearch(false);
+    QObject::connect(search, &SearchResult::activated,
+                     [](const Core::SearchResultItem& item) {
+                         Core::EditorManager::openEditorAtSearchResult(item);
+                     });
+    search->popup();
+}
+
 void CppEditorWidget::findUsages()
 {
-    if (!d->m_modelManager)
-        return;
-
-    SemanticInfo info = d->m_lastSemanticInfo;
-    info.snapshot = CppModelManager::instance()->snapshot();
-    info.snapshot.insert(info.doc);
-
-    if (const Macro *macro = CppTools::findCanonicalMacro(textCursor(), info.doc)) {
-        d->m_modelManager->findMacroUsages(*macro);
-    } else {
-        CanonicalSymbol cs(info.doc, info.snapshot);
-        Symbol *canonicalSymbol = cs(textCursor());
-        if (canonicalSymbol)
-            d->m_modelManager->findUsages(canonicalSymbol, cs.context());
-    }
+    refactoringEngine().findUsages(CppTools::CursorInEditor{textCursor(),
+                                                            textDocument()->filePath(),
+                                                            this},
+                                   [this](const CppTools::Usages &usages) {
+                                       findRenameCallback(textCursor(), usages);
+                                   });
 }
 
 void CppEditorWidget::renameUsagesInternal(const QString &replacement)