feat: add document symbol support

Fixes #417

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

@@ -20,6 +20,7 @@
 import com.redhat.devtools.lsp4ij.features.completion.LSPCompletionSupport;
 import com.redhat.devtools.lsp4ij.features.declaration.LSPDeclarationSupport;
 import com.redhat.devtools.lsp4ij.features.documentLink.LSPDocumentLinkSupport;
+import com.redhat.devtools.lsp4ij.features.documentSymbol.LSPDocumentSymbolSupport;
 import com.redhat.devtools.lsp4ij.features.documentation.LSPHoverSupport;
 import com.redhat.devtools.lsp4ij.features.foldingRange.LSPFoldingRangeSupport;
 import com.redhat.devtools.lsp4ij.features.formatting.LSPFormattingSupport;
@@ -81,6 +82,8 @@ public class LSPFileSupport extends UserDataHolderBase implements Disposable {
 
     private final LSPSemanticTokensSupport semanticTokensSupport;
 
+    private final LSPDocumentSymbolSupport documentSymbolSupport;
+
     private LSPFileSupport(@NotNull PsiFile file) {
         this.file = file;
         this.codeLensSupport = new LSPCodeLensSupport(file);
@@ -101,6 +104,7 @@ private LSPFileSupport(@NotNull PsiFile file) {
         this.declarationSupport = new LSPDeclarationSupport(file);
         this.typeDefinitionSupport = new LSPTypeDefinitionSupport(file);
         this.semanticTokensSupport = new LSPSemanticTokensSupport(file);
+        this.documentSymbolSupport = new LSPDocumentSymbolSupport(file);
         file.putUserData(LSP_FILE_SUPPORT_KEY, this);
     }
 
@@ -126,6 +130,7 @@ public void dispose() {
         getDeclarationSupport().cancel();
         getTypeDefinitionSupport().cancel();
         getSemanticTokensSupport().cancel();
+        getDocumentSymbolSupport().cancel();
         var map = getUserMap();
         for (var key : map.getKeys()) {
             var value = map.get(key);
@@ -297,6 +302,15 @@ public LSPSemanticTokensSupport getSemanticTokensSupport() {
         return semanticTokensSupport;
     }
 
+    /**
+     * Returns the LSP document symbol support.
+     *
+     * @return the LSP document symbol support.
+     */
+    public LSPDocumentSymbolSupport getDocumentSymbolSupport() {
+        return documentSymbolSupport;
+    }
+
     /**
      * Return the existing LSP file support for the given Psi file, or create a new one if necessary.
      *

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

@@ -46,6 +46,7 @@ public class LSPRequestConstants {
     public static final String TEXT_DOCUMENT_PREPARE_RENAME = "textDocument/prepareRename";
     public static final String TEXT_DOCUMENT_RENAME = "textDocument/rename";
     public static final String TEXT_DOCUMENT_DOCUMENT_COMPLETION = "textDocument/completion";
+    public static final String TEXT_DOCUMENT_DOCUMENT_SYMBOL = "textDocument/documentSymbol";
 
     // workspace/* LSP requests
     public static final String WORKSPACE_SYMBOL = "workspace/symbol";

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

@@ -513,6 +513,16 @@ public SemanticTokensColorsProvider getSemanticTokensColorsProvider() {
         return getServerWrapper().getServerDefinition().getSemanticTokensColorsProvider();
     }
 
+    /**
+     * Returns true if the language server can support document symbol and false otherwise.
+     *
+     * @return true if the language server can support document symbol and false otherwise.
+     */
+    public static boolean isDocumentSymbolSupported(@Nullable ServerCapabilities serverCapabilities) {
+        return serverCapabilities != null &&
+                hasCapability(serverCapabilities.getDocumentSymbolProvider());
+    }
+
     /**
      * Returns true if the language server can support workspace symbol and false otherwise.
      *

src/main/java/com/redhat/devtools/lsp4ij/features/documentSymbol/DocumentSymbolData.java

@@ -0,0 +1,57 @@
+/*******************************************************************************
+ * Copyright (c) 2024 Red Hat, Inc.
+ * Distributed under license by Red Hat, Inc. All rights reserved.
+ * This program is made available under the terms of the
+ * Eclipse Public License v2.0 which accompanies this distribution,
+ * and is available at https://www.eclipse.org/legal/epl-v20.html
+ *
+ * Contributors:
+ * CppCXY
+ ******************************************************************************/
+package com.redhat.devtools.lsp4ij.features.documentSymbol;
+
+import com.intellij.navigation.ItemPresentation;
+import com.intellij.openapi.util.NlsSafe;
+import com.redhat.devtools.lsp4ij.ui.IconMapper;
+import org.eclipse.lsp4j.DocumentSymbol;
+import org.eclipse.lsp4j.SymbolKind;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import javax.swing.*;
+
+
+/**
+ * LSP document symbol data.
+ *
+ * @param documentSymbol   the LSP document symbol
+ */
+record DocumentSymbolData(@NotNull DocumentSymbol documentSymbol) {
+
+    private record LSPItemPresentation(String name, SymbolKind symbolKind, String locationString) implements ItemPresentation {
+
+        public String name() {
+            return name;
+        }
+
+        @Override
+        public @NlsSafe @Nullable String getPresentableText() {
+            return name();
+        }
+
+        @Override
+        public @Nullable Icon getIcon(boolean unused) {
+            return IconMapper.getIcon(symbolKind);
+        }
+
+        @Override
+        public @NlsSafe @Nullable String getLocationString() {
+            return locationString;
+        }
+
+    }
+
+    public ItemPresentation getPresentation() {
+        return new LSPItemPresentation(documentSymbol.getName(), documentSymbol.getKind(), documentSymbol.getDetail());
+    }
+}

src/main/java/com/redhat/devtools/lsp4ij/features/documentSymbol/LSPDocumentSymbolStructureViewFactory.java

@@ -0,0 +1,48 @@
+/*******************************************************************************
+ * Copyright (c) 2024 Red Hat, Inc.
+ * Distributed under license by Red Hat, Inc. All rights reserved.
+ * This program is made available under the terms of the
+ * Eclipse Public License v2.0 which accompanies this distribution,
+ * and is available at https://www.eclipse.org/legal/epl-v20.html
+ *
+ * Contributors:
+ * CppCXY
+ ******************************************************************************/
+package com.redhat.devtools.lsp4ij.features.documentSymbol;
+
+import com.intellij.ide.structureView.StructureViewBuilder;
+import com.intellij.ide.structureView.StructureViewModel;
+import com.intellij.ide.structureView.TreeBasedStructureViewBuilder;
+import com.intellij.lang.PsiStructureViewFactory;
+import com.intellij.openapi.editor.Editor;
+import com.intellij.psi.PsiFile;
+import com.redhat.devtools.lsp4ij.LanguageServersRegistry;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * LSP document symbol structure view factory.
+ */
+public class LSPDocumentSymbolStructureViewFactory implements PsiStructureViewFactory {
+
+    @Override
+    public @Nullable StructureViewBuilder getStructureViewBuilder(@NotNull PsiFile psiFile) {
+        if (!LanguageServersRegistry.getInstance().isFileSupported(psiFile)) {
+            return null;
+        }
+        return new LSPDocumentSymbolStructureViewBuilder(psiFile);
+    }
+
+    private static class LSPDocumentSymbolStructureViewBuilder extends TreeBasedStructureViewBuilder {
+        private final PsiFile psiFile;
+
+        public LSPDocumentSymbolStructureViewBuilder(@NotNull PsiFile psiFile) {
+            this.psiFile = psiFile;
+        }
+
+        @Override
+        public @NotNull StructureViewModel createStructureViewModel(@Nullable Editor editor) {
+            return new LSPDocumentSymbolStructureViewModel(psiFile, editor);
+        }
+    }
+}