ClangCodeModel: Add experimental clangd support

If the user has enabled clangd (default is off), we start up one instance
per project when it is opened/changed (including build config switches),
and trigger background indexing.
So far, the index is used to provide results for locators and "Find
Usages".
Per-document functionality such as semantic highlighting and completion
is still provided by libclang.

Change-Id: I12532fca1b9c6278baab560e7238cba6189cde9f
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/languageclient/client.cpp

@@ -292,7 +292,7 @@ void Client::initialize()
     QTC_ASSERT(m_state == Uninitialized, return);
     qCDebug(LOGLSPCLIENT) << "initializing language server " << m_displayName;
     InitializeParams params;
-    params.setCapabilities(generateClientCapabilities());
+    params.setCapabilities(m_clientCapabilities);
     params.setInitializationOptions(m_initializationOptions);
     if (m_project) {
         params.setRootUri(DocumentUri::fromFilePath(m_project->projectDirectory()));
@@ -333,6 +333,16 @@ Client::State Client::state() const
     return m_state;
 }
 
+ClientCapabilities Client::defaultClientCapabilities()
+{
+    return generateClientCapabilities();
+}
+
+void Client::setClientCapabilities(const LanguageServerProtocol::ClientCapabilities &caps)
+{
+    m_clientCapabilities = caps;
+}
+
 void Client::openDocument(TextEditor::TextDocument *document)
 {
     using namespace TextEditor;
@@ -532,6 +542,9 @@ void Client::requestDocumentHighlights(TextEditor::TextEditorWidget *widget)
 
 void Client::activateDocument(TextEditor::TextDocument *document)
 {
+    if (!m_documentActionsEnabled)
+        return;
+
     auto uri = DocumentUri::fromFilePath(document->filePath());
     m_diagnosticManager.showDiagnostics(uri);
     SemanticHighligtingSupport::applyHighlight(document, m_highlights.value(uri), capabilities());
@@ -558,6 +571,9 @@ void Client::activateDocument(TextEditor::TextDocument *document)
 
 void Client::deactivateDocument(TextEditor::TextDocument *document)
 {
+    if (!m_documentActionsEnabled)
+        return;
+
     m_diagnosticManager.hideDiagnostics(document);
     resetAssistProviders(document);
     document->setFormatter(nullptr);
@@ -1241,6 +1257,9 @@ void Client::handleMethod(const QString &method, const MessageId &id, const ICon
 
 void Client::handleDiagnostics(const PublishDiagnosticsParams &params)
 {
+    if (!m_documentActionsEnabled)
+        return;
+
     const DocumentUri &uri = params.uri();
 
     const QList<Diagnostic> &diagnostics = params.diagnostics();
@@ -1253,6 +1272,9 @@ void Client::handleDiagnostics(const PublishDiagnosticsParams &params)
 
 void Client::handleSemanticHighlight(const SemanticHighlightingParams &params)
 {
+    if (!m_documentActionsEnabled)
+        return;
+
     DocumentUri uri;
     LanguageClientValue<int> version;
     auto textDocument = params.textDocument();
@@ -1283,6 +1305,9 @@ void Client::handleSemanticHighlight(const SemanticHighlightingParams &params)
 
 void Client::rehighlight()
 {
+    if (!m_documentActionsEnabled)
+        return;
+
     using namespace TextEditor;
     for (auto it = m_highlights.begin(), end = m_highlights.end(); it != end; ++it) {
         if (TextDocument *doc = TextDocument::textDocumentForFilePath(it.key().toFilePath())) {

src/plugins/languageclient/client.h

@@ -113,11 +113,17 @@ public:
     bool reachable() const { return m_state == Initialized; }
 
     // capabilities
+    static LanguageServerProtocol::ClientCapabilities defaultClientCapabilities();
+    void setClientCapabilities(const LanguageServerProtocol::ClientCapabilities &caps);
     const LanguageServerProtocol::ServerCapabilities &capabilities() const;
     const DynamicCapabilities &dynamicCapabilities() const;
     void registerCapabilities(const QList<LanguageServerProtocol::Registration> &registrations);
     void unregisterCapabilities(const QList<LanguageServerProtocol::Unregistration> &unregistrations);
 
+    void setLocatorsEnabled(bool enabled) { m_locatorsEnabled = enabled; }
+    bool locatorsEnabled() const { return m_locatorsEnabled; }
+    void setDocumentActionsEnabled(bool enabled) { m_documentActionsEnabled = enabled; }
+
     // document synchronization
     void setSupportedLanguage(const LanguageFilter &filter);
     void setActivateDocumentAutomatically(bool enabled);
@@ -226,6 +232,7 @@ private:
     QMap<TextEditor::TextEditorWidget *, QTimer *> m_documentHighlightsTimer;
     QTimer m_documentUpdateTimer;
     Utils::Id m_id;
+    LanguageServerProtocol::ClientCapabilities m_clientCapabilities = defaultClientCapabilities();
     LanguageServerProtocol::ServerCapabilities m_serverCapabilities;
     DynamicCapabilities m_dynamicCapabilities;
     struct AssistProviders
@@ -250,6 +257,8 @@ private:
     ProgressManager m_progressManager;
     bool m_activateDocAutomatically = false;
     SemanticTokenSupport m_tokentSupport;
+    bool m_locatorsEnabled = true;
+    bool m_documentActionsEnabled = true;
 };
 
 } // namespace LanguageClient

src/plugins/languageclient/languageclient.qbs

@@ -57,4 +57,6 @@ QtcPlugin {
         "semantichighlightsupport.cpp",
         "semantichighlightsupport.h",
     ]
+
+    Export { Depends { name: "LanguageServerProtocol" } }
 }

src/plugins/languageclient/languageclientmanager.cpp

@@ -40,6 +40,7 @@
 #include <texteditor/textdocument.h>
 #include <texteditor/texteditor.h>
 #include <texteditor/textmark.h>
+#include <utils/algorithm.h>
 #include <utils/executeondestruction.h>
 #include <utils/mimetypes/mimedatabase.h>
 #include <utils/theme/theme.h>
@@ -375,6 +376,14 @@ Client *LanguageClientManager::clientForUri(const DocumentUri &uri)
     return clientForFilePath(uri.toFilePath());
 }
 
+const QList<Client *> LanguageClientManager::clientsForProject(
+        const ProjectExplorer::Project *project)
+{
+    return Utils::filtered(managerInstance->m_clients, [project](const Client *c) {
+        return c->project() == project;
+    }).toList();
+}
+
 void LanguageClientManager::openDocumentWithClient(TextEditor::TextDocument *document, Client *client)
 {
     Client *currentClient = clientForDocument(document);

src/plugins/languageclient/languageclientmanager.h

@@ -84,6 +84,7 @@ public:
     static Client *clientForDocument(TextEditor::TextDocument *document);
     static Client *clientForFilePath(const Utils::FilePath &filePath);
     static Client *clientForUri(const LanguageServerProtocol::DocumentUri &uri);
+    static const QList<Client *> clientsForProject(const ProjectExplorer::Project *project);
 
     ///
     /// \brief openDocumentWithClient

src/plugins/languageclient/languageclientsymbolsupport.h

@@ -25,6 +25,8 @@
 
 #pragma once
 
+#include "languageclient_global.h"
+
 #include <texteditor/textdocument.h>
 
 #include <languageserverprotocol/languagefeatures.h>
@@ -38,7 +40,7 @@ namespace LanguageClient {
 
 class Client;
 
-class SymbolSupport
+class LANGUAGECLIENT_EXPORT SymbolSupport
 {
     Q_DECLARE_TR_FUNCTIONS(SymbolSupport)
 public:

src/plugins/languageclient/locatorfilter.cpp

@@ -214,6 +214,18 @@ WorkspaceLocatorFilter::WorkspaceLocatorFilter(const QVector<SymbolKind> &filter
 }
 
 void WorkspaceLocatorFilter::prepareSearch(const QString &entry)
+{
+    prepareSearch(entry, LanguageClientManager::clients(), false);
+}
+
+void WorkspaceLocatorFilter::prepareSearch(const QString &entry, const QVector<Client *> &clients)
+{
+    prepareSearch(entry, clients, true);
+}
+
+void WorkspaceLocatorFilter::prepareSearch(const QString &entry,
+                                           const QVector<Client *> &clients,
+                                           bool force)
 {
     m_pendingRequests.clear();
     m_results.clear();
@@ -222,7 +234,11 @@ void WorkspaceLocatorFilter::prepareSearch(const QString &entry)
     params.setQuery(entry);
 
     QMutexLocker locker(&m_mutex);
-    for (auto client : Utils::filtered(LanguageClientManager::clients(), &Client::reachable)) {
+    for (auto client : qAsConst(clients)) {
+        if (!client->reachable())
+            continue;
+        if (!(force || client->locatorsEnabled()))
+            continue;
         Utils::optional<Utils::variant<bool, WorkDoneProgressOptions>> capability
             = client->capabilities().workspaceSymbolProvider();
         if (!capability.has_value())

src/plugins/languageclient/locatorfilter.h

@@ -74,13 +74,16 @@ private:
     Utils::optional<LanguageServerProtocol::DocumentSymbolsResult> m_currentSymbols;
 };
 
-class WorkspaceLocatorFilter : public Core::ILocatorFilter
+class LANGUAGECLIENT_EXPORT WorkspaceLocatorFilter : public Core::ILocatorFilter
 {
     Q_OBJECT
 public:
     WorkspaceLocatorFilter();
 
+    /// request workspace symbols for all clients with enabled locator
     void prepareSearch(const QString &entry) override;
+    /// force request workspace symbols for all given clients
+    void prepareSearch(const QString &entry, const QVector<Client *> &clients);
     QList<Core::LocatorFilterEntry> matchesFor(QFutureInterface<Core::LocatorFilterEntry> &future,
                                                const QString &entry) override;
     void accept(Core::LocatorFilterEntry selection,
@@ -95,6 +98,7 @@ protected:
     explicit WorkspaceLocatorFilter(const QVector<LanguageServerProtocol::SymbolKind> &filter);
 
 private:
+    void prepareSearch(const QString &entry, const QVector<Client *> &clients, bool force);
     void handleResponse(Client *client,
                         const LanguageServerProtocol::WorkspaceSymbolRequest::Response &response);
 
@@ -104,13 +108,13 @@ private:
     QVector<LanguageServerProtocol::SymbolKind> m_filterKinds;
 };
 
-class WorkspaceClassLocatorFilter : public WorkspaceLocatorFilter
+class LANGUAGECLIENT_EXPORT WorkspaceClassLocatorFilter : public WorkspaceLocatorFilter
 {
 public:
     WorkspaceClassLocatorFilter();
 };
 
-class WorkspaceMethodLocatorFilter : public WorkspaceLocatorFilter
+class LANGUAGECLIENT_EXPORT WorkspaceMethodLocatorFilter : public WorkspaceLocatorFilter
 {
 public:
     WorkspaceMethodLocatorFilter();