feat: provide LSP API support

Signed-off-by: azerr <azerr@redhat.com>

src/main/java/com/redhat/devtools/lsp4ij/ConnectDocumentToLanguageServerSetupParticipant.java

@@ -80,7 +80,7 @@ private static void connectToLanguageServer(@NotNull VirtualFile file, @NotNull
         // Server capabilities filter is set to null to avoid waiting
         // for the start of the server when server capabilities are checked
         LanguageServiceAccessor.getInstance(project)
-                .getLanguageServers(file, null);
+                .getLanguageServers(file, null, null);
     }
 
 }

src/main/java/com/redhat/devtools/lsp4ij/LanguageServerFactory.java

@@ -13,6 +13,7 @@
 import com.intellij.openapi.project.Project;
 import com.redhat.devtools.lsp4ij.client.LanguageClientImpl;
 import com.redhat.devtools.lsp4ij.server.StreamConnectionProvider;
+import com.redhat.devtools.lsp4ij.client.features.LSPClientFeatures;
 import org.eclipse.lsp4j.services.LanguageServer;
 import org.jetbrains.annotations.NotNull;
 
@@ -50,4 +51,7 @@ public interface LanguageServerFactory {
         return LanguageServer.class;
     }
 
+    @NotNull default LSPClientFeatures createClientFeatures() {
+        return new LSPClientFeatures();
+    }
 }

src/main/java/com/redhat/devtools/lsp4ij/LanguageServerItem.java

@@ -11,6 +11,7 @@
 package com.redhat.devtools.lsp4ij;
 
 import com.intellij.psi.PsiFile;
+import com.redhat.devtools.lsp4ij.client.features.LSPClientFeatures;
 import com.redhat.devtools.lsp4ij.features.semanticTokens.SemanticTokensColorsProvider;
 import org.eclipse.lsp4j.*;
 import org.eclipse.lsp4j.jsonrpc.messages.Either;
@@ -52,6 +53,15 @@ public LanguageServerWrapper getServerWrapper() {
         return serverWrapper;
     }
 
+    /**
+     * Returns the LSP client features.
+     *
+     * @return the LSP client features.
+     */
+    public LSPClientFeatures getClientFeatures() {
+        return getServerWrapper().getClientFeatures();
+    }
+
     /**
      * Returns the server capabilities of the language server.
      *
@@ -340,12 +350,12 @@ public static boolean isImplementationSupported(@Nullable ServerCapabilities ser
     }
 
     /**
-     * Returns true if the language server can support folding and false otherwise.
+     * Returns true if the language server can support folding range and false otherwise.
      *
      * @param serverCapabilities the server capabilities.
-     * @return true if the language server can support folding and false otherwise.
+     * @return true if the language server can support folding range and false otherwise.
      */
-    public static boolean isFoldingSupported(@Nullable ServerCapabilities serverCapabilities) {
+    public static boolean isFoldingRangeSupported(@Nullable ServerCapabilities serverCapabilities) {
         return serverCapabilities != null &&
                 hasCapability(serverCapabilities.getFoldingRangeProvider());
     }
@@ -510,7 +520,7 @@ private static boolean hasCapability(Boolean capability) {
     }
 
     public SemanticTokensColorsProvider getSemanticTokensColorsProvider() {
-        return getServerWrapper().getServerDefinition().getSemanticTokensColorsProvider();
+        return getClientFeatures().getSemanticTokensFeature();
     }
 
     /**
@@ -542,4 +552,12 @@ public static boolean isWorkspaceSymbolSupported(@Nullable ServerCapabilities se
         return serverCapabilities != null &&
                 hasCapability(serverCapabilities.getWorkspaceSymbolProvider());
     }
+
+    public static boolean isUsageSupported(ServerCapabilities serverCapabilities) {
+        return LanguageServerItem.isDeclarationSupported(serverCapabilities) ||
+                LanguageServerItem.isTypeDefinitionSupported(serverCapabilities) ||
+                LanguageServerItem.isDefinitionSupported(serverCapabilities) ||
+                LanguageServerItem.isReferencesSupported(serverCapabilities) ||
+                LanguageServerItem.isImplementationSupported(serverCapabilities);
+    }
 }

src/main/java/com/redhat/devtools/lsp4ij/LanguageServerWrapper.java

@@ -31,6 +31,7 @@
 import com.redhat.devtools.lsp4ij.lifecycle.LanguageServerLifecycleManager;
 import com.redhat.devtools.lsp4ij.lifecycle.NullLanguageServerLifecycleManager;
 import com.redhat.devtools.lsp4ij.server.*;
+import com.redhat.devtools.lsp4ij.client.features.LSPClientFeatures;
 import com.redhat.devtools.lsp4ij.server.definition.LanguageServerDefinition;
 import org.eclipse.lsp4j.*;
 import org.eclipse.lsp4j.jsonrpc.Launcher;
@@ -108,6 +109,8 @@ public class LanguageServerWrapper implements Disposable {
 
     private FileOperationsManager fileOperationsManager;
 
+    private LSPClientFeatures clientFeatures;
+
     /* Backwards compatible constructor */
     public LanguageServerWrapper(@NotNull Project project, @NotNull LanguageServerDefinition serverDefinition) {
         this(project, serverDefinition, null);
@@ -408,6 +411,9 @@ public void dispose() {
         this.disposed = true;
         stop();
         stopDispatcher();
+        if (clientFeatures != null) {
+            clientFeatures.dispose();
+        }
     }
 
     public boolean isDisposed() {
@@ -708,7 +714,7 @@ public void disconnect(URI path, boolean stopIfNoOpenedFiles) {
             synchronizer.getDocument().removeDocumentListener(synchronizer);
             synchronizer.documentClosed();
         }
-        if (stopIfNoOpenedFiles && this.connectedDocuments.isEmpty()) {
+        if (getClientFeatures().isServerStoppingRequiredWhenFilesClosed() && stopIfNoOpenedFiles && this.connectedDocuments.isEmpty()) {
             if (this.serverDefinition.getLastDocumentDisconnectedTimeout() != 0 && !ApplicationManager.getApplication().isUnitTestMode()) {
                 removeStopTimer(true);
                 startStopTimer();
@@ -1174,4 +1180,20 @@ public boolean isSignatureTriggerCharactersSupported(String charTyped) {
         }
         return triggerCharacters.contains(charTyped);
     }
+
+    public LSPClientFeatures getClientFeatures() {
+        if (clientFeatures == null) {
+            clientFeatures = getOrCreateClientFeatures();
+        }
+        return clientFeatures;
+    }
+
+    private synchronized LSPClientFeatures getOrCreateClientFeatures() {
+        if  (clientFeatures != null) {
+            return clientFeatures;
+        }
+        LSPClientFeatures clientFeatures = getServerDefinition().createClientFeatures();
+        clientFeatures.setServerWrapper(this);
+        return clientFeatures;
+    }
 }