Add LSP support (#68) [paid versions of IDEA only]

CHANGELOG.md

@@ -5,6 +5,8 @@
 ### Added
 
 - Plugin logo for easier recognition
+- Experimental Language Server support using IDEA's LSP API (#68)  
+  [(Only works for paid versions of IDEA :disappointed:)](https://blog.jetbrains.com/platform/2023/07/lsp-for-plugin-developers/#supported-ides)
 
 ### Changed
 

build.gradle.kts

@@ -1,6 +1,7 @@
 import org.jetbrains.changelog.Changelog
 import org.jetbrains.changelog.markdownToHTML
-import org.jetbrains.intellij.tasks.RunPluginVerifierTask
+import org.jetbrains.intellij.tasks.RunPluginVerifierTask.FailureLevel
+import java.util.EnumSet
 
 plugins {
     id("java")
@@ -167,7 +168,7 @@ tasks {
     }
 
     runPluginVerifier {
-        failureLevel = RunPluginVerifierTask.FailureLevel.ALL
+        failureLevel = EnumSet.complementOf(EnumSet.of(FailureLevel.EXPERIMENTAL_API_USAGES))
         // Version 1.364 seems to be broken and always complains about supposedly missing 'plugin.xml':
         // https://youtrack.jetbrains.com/issue/MP-6388
         verifierVersion = "1.307"

gradle.properties

@@ -4,11 +4,12 @@
 pluginGroup = org.nixos.idea
 pluginName = NixIDEA
 pluginVersion = 0.4.0.13
-pluginSinceBuild = 231
+pluginSinceBuild = 232
 pluginUntilBuild = 241.*
 
-platformType = IC
-platformVersion = 2023.1.6
+platformType = IU
+# TODO Revert to 2023.2.6?
+platformVersion = 2024.1
 
 # Gradle Configuration
 # -> https://docs.gradle.org/current/userguide/build_environment.html#sec:gradle_configuration_properties

src/main/java/org/nixos/idea/lsp/NixLspServerDescriptor.java

@@ -0,0 +1,34 @@
+package org.nixos.idea.lsp;
+
+import com.intellij.execution.ExecutionException;
+import com.intellij.execution.configurations.GeneralCommandLine;
+import com.intellij.openapi.project.Project;
+import com.intellij.openapi.vfs.VirtualFile;
+import com.intellij.platform.lsp.api.ProjectWideLspServerDescriptor;
+import com.intellij.util.execution.ParametersListUtil;
+import org.jetbrains.annotations.NotNull;
+import org.nixos.idea.file.NixFileType;
+
+import java.util.List;
+
+@SuppressWarnings("UnstableApiUsage")
+final class NixLspServerDescriptor extends ProjectWideLspServerDescriptor {
+
+    private final String myCommand;
+
+    NixLspServerDescriptor(@NotNull Project project, NixLspSettings settings) {
+        super(project, "Nix");
+        myCommand = settings.getCommand();
+    }
+
+    @Override
+    public @NotNull GeneralCommandLine createCommandLine() throws ExecutionException {
+        List<String> argv = ParametersListUtil.parse(myCommand, false, true);
+        return new GeneralCommandLine(argv);
+    }
+
+    @Override
+    public boolean isSupportedFile(@NotNull VirtualFile virtualFile) {
+        return virtualFile.getFileType() == NixFileType.INSTANCE;
+    }
+}

src/main/java/org/nixos/idea/lsp/NixLspServerSupportProvider.java

@@ -0,0 +1,29 @@
+package org.nixos.idea.lsp;
+
+import com.intellij.openapi.project.Project;
+import com.intellij.openapi.vfs.VirtualFile;
+import com.intellij.platform.lsp.api.LspServer;
+import com.intellij.platform.lsp.api.LspServerSupportProvider;
+import com.intellij.platform.lsp.api.lsWidget.LspServerWidgetItem;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.nixos.idea.file.NixFileType;
+import org.nixos.idea.icon.NixIcons;
+
+@SuppressWarnings("UnstableApiUsage")
+public final class NixLspServerSupportProvider implements LspServerSupportProvider {
+    @Override
+    public void fileOpened(@NotNull Project project, @NotNull VirtualFile virtualFile, @NotNull LspServerStarter lspServerStarter) {
+        if (virtualFile.getFileType() == NixFileType.INSTANCE) {
+            NixLspSettings settings = NixLspSettings.getInstance();
+            if (settings.isEnabled()) {
+                lspServerStarter.ensureServerStarted(new NixLspServerDescriptor(project, settings));
+            }
+        }
+    }
+
+    @Override
+    public @NotNull LspServerWidgetItem createLspServerWidgetItem(@NotNull LspServer lspServer, @Nullable VirtualFile currentFile) {
+        return new LspServerWidgetItem(lspServer, currentFile, NixIcons.FILE, NixLspSettingsConfigurable.class);
+    }
+}

src/main/java/org/nixos/idea/lsp/NixLspSettings.java

@@ -0,0 +1,54 @@
+package org.nixos.idea.lsp;
+
+import com.intellij.openapi.application.ApplicationManager;
+import com.intellij.openapi.components.PersistentStateComponent;
+import com.intellij.openapi.components.RoamingType;
+import com.intellij.openapi.components.State;
+import com.intellij.openapi.components.Storage;
+import org.jetbrains.annotations.NotNull;
+
+@State(name = "NixLspSettings", storages = @Storage(value = "nix-idea-tools.xml", roamingType = RoamingType.LOCAL))
+public final class NixLspSettings implements PersistentStateComponent<NixLspSettings.State> {
+
+    // Documentation:
+    // https://plugins.jetbrains.com/docs/intellij/persisting-state-of-components.html
+
+    private @NotNull State myState = new State();
+
+    public static @NotNull NixLspSettings getInstance() {
+        return ApplicationManager.getApplication().getService(NixLspSettings.class);
+    }
+
+    public boolean isEnabled() {
+        return myState.enabled;
+    }
+
+    public void setEnabled(boolean enabled) {
+        myState.enabled = enabled;
+    }
+
+    public @NotNull String getCommand() {
+        return myState.command;
+    }
+
+    public void setCommand(@NotNull String command) {
+        myState.command = command;
+    }
+
+    @SuppressWarnings("ClassEscapesDefinedScope")
+    @Override
+    public void loadState(@NotNull State state) {
+        myState = state;
+    }
+
+    @SuppressWarnings("ClassEscapesDefinedScope")
+    @Override
+    public @NotNull State getState() {
+        return myState;
+    }
+
+    static final class State {
+        public boolean enabled = false;
+        public @NotNull String command = "";
+    }
+}

src/main/java/org/nixos/idea/lsp/NixLspSettingsConfigurable.java

@@ -0,0 +1,100 @@
+package org.nixos.idea.lsp;
+
+import com.intellij.openapi.options.Configurable;
+import com.intellij.openapi.options.ConfigurationException;
+import com.intellij.openapi.options.SearchableConfigurable;
+import com.intellij.openapi.project.Project;
+import com.intellij.openapi.project.ProjectManager;
+import com.intellij.openapi.util.NlsContexts;
+import com.intellij.platform.lsp.api.LspServerManager;
+import com.intellij.ui.RawCommandLineEditor;
+import com.intellij.ui.TitledSeparator;
+import com.intellij.ui.components.JBCheckBox;
+import com.intellij.util.ui.FormBuilder;
+import org.jetbrains.annotations.NonNls;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import javax.swing.JComponent;
+import javax.swing.JPanel;
+
+public class NixLspSettingsConfigurable implements SearchableConfigurable, Configurable.Beta {
+
+    private @Nullable JBCheckBox myEnabled;
+    private @Nullable RawCommandLineEditor myCommand;
+
+    @Override
+    public @NotNull @NonNls String getId() {
+        return "org.nixos.idea.lsp.NixLspSettings";
+    }
+
+    @Override
+    public @NlsContexts.ConfigurableName String getDisplayName() {
+        return "Language Server (LSP)";
+    }
+
+    @Override
+    public @Nullable JComponent createComponent() {
+        myEnabled = new JBCheckBox("Enable language server");
+        myEnabled.addChangeListener(e -> updateUiState());
+
+        myCommand = new RawCommandLineEditor();
+        myCommand.getEditorField().getEmptyText().setText("Command to start Language Server");
+        myCommand.getEditorField().getAccessibleContext().setAccessibleName("Command to start Language Server");
+        myCommand.getEditorField().setMargin(myEnabled.getMargin());
+
+        // TODO: Add suggestions somehow
+        //myCommand.getComponentPopupMenu().add(new JBMenuItem("nix --extra-experimental-features "nix-command flakes" run nixpkgs#nil"));
+
+        return FormBuilder.createFormBuilder()
+                .addComponent(myEnabled)
+                .addComponent(new TitledSeparator("Language Server Configuration"))
+                .addLabeledComponent("Command: ", myCommand)
+                .addComponentFillVertically(new JPanel(), 0)
+                .getPanel();
+    }
+
+    @Override
+    public void reset() {
+        assert myEnabled != null;
+        assert myCommand != null;
+
+        NixLspSettings settings = NixLspSettings.getInstance();
+        myEnabled.setSelected(settings.isEnabled());
+        myCommand.setText(settings.getCommand());
+
+        updateUiState();
+    }
+
+    @SuppressWarnings("UnstableApiUsage")
+    @Override
+    public void apply() throws ConfigurationException {
+        assert myEnabled != null;
+        assert myCommand != null;
+
+        NixLspSettings settings = NixLspSettings.getInstance();
+        settings.setEnabled(myEnabled.isSelected());
+        settings.setCommand(myCommand.getText());
+
+        for (Project project : ProjectManager.getInstance().getOpenProjects()) {
+            LspServerManager.getInstance(project).stopAndRestartIfNeeded(NixLspServerSupportProvider.class);
+        }
+    }
+
+    @Override
+    public boolean isModified() {
+        assert myEnabled != null;
+        assert myCommand != null;
+
+        NixLspSettings settings = NixLspSettings.getInstance();
+        return Configurable.isCheckboxModified(myEnabled, settings.isEnabled()) ||
+                Configurable.isFieldModified(myCommand.getTextField(), settings.getCommand());
+    }
+
+    private void updateUiState() {
+        assert myEnabled != null;
+        assert myCommand != null;
+
+        myCommand.setEnabled(myEnabled.isSelected());
+    }
+}

src/main/resources/META-INF/plugin.xml

@@ -5,6 +5,7 @@
     <vendor>NixOS</vendor>
 
     <depends>com.intellij.modules.lang</depends>
+    <depends>com.intellij.modules.platform</depends>
 
     <extensions defaultExtensionNs="com.intellij">
 
@@ -38,14 +39,26 @@
                 implementationClass="org.nixos.idea.lang.NixCommenter"/>
 
         <projectConfigurable
-                groupId="build"
+                parentId="build"
                 displayName="NixIDEA Settings"
                 id="org.nixos.idea.settings.NixIDEASettings"
                 instance="org.nixos.idea.settings.NixIDEASettings" />
 
         <colorSettingsPage
                 implementation="org.nixos.idea.settings.NixColorSettingsPage" />
 
+        <applicationConfigurable
+                parentId="language"
+                displayName="Nix Language Server (LSP)"
+                id="org.nixos.idea.lsp.NixLspSettingsConfigurable"
+                instance="org.nixos.idea.lsp.NixLspSettingsConfigurable"/>
+
+        <applicationService
+                serviceImplementation="org.nixos.idea.lsp.NixLspSettings"/>
+
+        <platform.lsp.serverSupportProvider
+                implementation="org.nixos.idea.lsp.NixLspServerSupportProvider"/>
+
     </extensions>
 
 </idea-plugin>