LanguageClient: Add option to start server when needed

Until now all servers where startet on creator startup. Change this
default to start server when first file that matches the configured
filter is opened. Additionally add an option that restores the old
behavior of always on servers.

Change-Id: I595e0ede1cf136cc803181377155bcd58ca1a83c
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/languageclient/languageclientsettings.cpp

@@ -30,7 +30,9 @@
 #include "languageclient_global.h"
 #include "languageclientinterface.h"
 
+#include <coreplugin/editormanager/documentmodel.h>
 #include <coreplugin/icore.h>
+#include <coreplugin/idocument.h>
 #include <coreplugin/variablechooser.h>
 #include <utils/algorithm.h>
 #include <utils/delegates.h>
@@ -58,6 +60,7 @@
 
 constexpr char nameKey[] = "name";
 constexpr char enabledKey[] = "enabled";
+constexpr char alwaysOnKey[] = "alwaysOn";
 constexpr char mimeTypeKey[] = "mimeType";
 constexpr char filePatternKey[] = "filePattern";
 constexpr char executableKey[] = "executable";
@@ -271,11 +274,15 @@ void LanguageClientSettingsPage::apply()
         }
     }
     for (StdIOSettings *setting : restarts) {
-        if (setting && setting->isValid() && setting->m_enabled) {
-            if (auto client = setting->createClient()) {
-                setting->m_client = client;
-                LanguageClientManager::startClient(client);
-            }
+        if (setting->isValid() && setting->m_enabled) {
+            const bool start = setting->m_alwaysOn
+                               || Utils::anyOf(Core::DocumentModel::openedDocuments(),
+                                               [filter = setting->m_languageFilter](
+                                                   Core::IDocument *doc) {
+                                                   return filter.isSupported(doc);
+                                               });
+            if (start)
+                setting->startClient();
         }
     }
 
@@ -386,6 +393,7 @@ void BaseSettings::applyFromSettingsWidget(QWidget *widget)
     if (auto settingsWidget = qobject_cast<BaseSettingsWidget *>(widget)) {
         m_name = settingsWidget->name();
         m_languageFilter = settingsWidget->filter();
+        m_alwaysOn = settingsWidget->alwaysOn();
     }
 }
 
@@ -404,16 +412,17 @@ bool BaseSettings::isValid() const
     return !m_name.isEmpty();
 }
 
-Client *BaseSettings::createClient() const
+void BaseSettings::startClient()
 {
+    if (!isValid() || !m_enabled)
+        return;
     BaseClientInterface *interface = createInterface();
-    if (QTC_GUARD(interface)) {
-        auto *client = new Client(interface);
-        client->setName(Utils::globalMacroExpander()->expand(m_name));
-        client->setSupportedLanguage(m_languageFilter);
-        return client;
-    }
-    return nullptr;
+    QTC_ASSERT(interface, return);
+    auto *client = new Client(interface);
+    client->setName(Utils::globalMacroExpander()->expand(m_name));
+    client->setSupportedLanguage(m_languageFilter);
+    m_client = client;
+    LanguageClientManager::startClient(client);
 }
 
 QVariantMap BaseSettings::toMap() const
@@ -421,6 +430,7 @@ QVariantMap BaseSettings::toMap() const
     QVariantMap map;
     map.insert(nameKey, m_name);
     map.insert(enabledKey, m_enabled);
+    map.insert(alwaysOnKey, m_alwaysOn);
     map.insert(mimeTypeKey, m_languageFilter.mimeTypes);
     map.insert(filePatternKey, m_languageFilter.filePattern);
     return map;
@@ -430,6 +440,7 @@ void BaseSettings::fromMap(const QVariantMap &map)
 {
     m_name = map[nameKey].toString();
     m_enabled = map[enabledKey].toBool();
+    m_alwaysOn = map.value(alwaysOnKey, false).toBool();
     m_languageFilter.mimeTypes = map[mimeTypeKey].toStringList();
     m_languageFilter.filePattern = map[filePatternKey].toStringList();
 }
@@ -546,6 +557,7 @@ BaseSettingsWidget::BaseSettingsWidget(const BaseSettings *settings, QWidget *pa
     , m_name(new QLineEdit(settings->m_name, this))
     , m_mimeTypes(new QLabel(settings->m_languageFilter.mimeTypes.join(filterSeparator), this))
     , m_filePattern(new QLineEdit(settings->m_languageFilter.filePattern.join(filterSeparator), this))
+    , m_alwaysOn(new QCheckBox())
 {
     int row = 0;
     auto *mainLayout = new QGridLayout;
@@ -562,6 +574,9 @@ BaseSettingsWidget::BaseSettingsWidget(const BaseSettings *settings, QWidget *pa
     mainLayout->addLayout(mimeLayout, row, 1);
     m_filePattern->setPlaceholderText(tr("File pattern"));
     mainLayout->addWidget(m_filePattern, ++row, 1);
+    mainLayout->addWidget(new QLabel(tr("Always On:")), ++row, 0);
+    mainLayout->addWidget(m_alwaysOn, row, 1);
+    m_alwaysOn->setChecked(settings->m_alwaysOn);
 
     connect(addMimeTypeButton, &QPushButton::pressed,
             this, &BaseSettingsWidget::showAddMimeTypeDialog);
@@ -604,6 +619,11 @@ LanguageFilter BaseSettingsWidget::filter() const
                 m_filePattern->text().split(filterSeparator)};
 }
 
+bool BaseSettingsWidget::alwaysOn() const
+{
+    return m_alwaysOn->isChecked();
+}
+
 class MimeTypeModel : public QStringListModel
 {
 public:
@@ -741,4 +761,9 @@ bool LanguageFilter::isSupported(const Utils::FileName &filePath, const QString
     });
 }
 
+bool LanguageFilter::isSupported(const Core::IDocument *document) const
+{
+    return isSupported(document->filePath(), document->mimeType());
+}
+
 } // namespace LanguageClient