Fixed: Lag caused due to a large number of diagnostic items in RecyclerView

app/src/main/AndroidManifest.xml

@@ -26,6 +26,8 @@
         android:supportsRtl="true"
         android:theme="@style/AppTheme"
         tools:ignore="UnusedAttribute,MediaCapabilities">
+        <profileable android:shell="true" />
+
         <activity
             android:name=".CrashHandlerActivity"
             android:exported="true"

app/src/main/java/com/itsaky/androidide/EditorActivity.java

@@ -241,6 +241,7 @@ public class EditorActivity extends StudioActivity
 
   @Override
   public boolean onPrepareOptionsMenu(Menu menu) {
+    LOG.debug("Prepare options menu");
     ensureToolbarMenu(menu);
     return true;
   }

app/src/main/java/com/itsaky/androidide/adapters/DiagnosticItemAdapter.java

@@ -33,16 +33,17 @@ import com.itsaky.lsp.models.DiagnosticSeverity;
 
 import java.io.File;
 import java.util.List;
+import java.util.Objects;
 
 public class DiagnosticItemAdapter extends RecyclerView.Adapter<DiagnosticItemAdapter.VH> {
 
-  private final List<DiagnosticItem> diags;
+  private final List<DiagnosticItem> diagnostics;
   private final File file;
   private final DiagnosticClickListener listener;
 
   public DiagnosticItemAdapter(
-      List<DiagnosticItem> diags, File file, DiagnosticClickListener listener) {
-    this.diags = diags;
+      List<DiagnosticItem> diagnostics, File file, DiagnosticClickListener listener) {
+    this.diagnostics = Objects.requireNonNull(diagnostics);
     this.file = file;
     this.listener = listener;
   }
@@ -56,7 +57,7 @@ public class DiagnosticItemAdapter extends RecyclerView.Adapter<DiagnosticItemAd
 
   @Override
   public void onBindViewHolder(DiagnosticItemAdapter.VH p1, int p2) {
-    final DiagnosticItem diagnostic = diags.get(p2);
+    final DiagnosticItem diagnostic = diagnostics.get(p2);
     final LayoutDiagnosticItemBinding binding = p1.binding;
 
     binding.icon.setImageResource(getDiagnosticIconId(diagnostic));
@@ -81,7 +82,7 @@ public class DiagnosticItemAdapter extends RecyclerView.Adapter<DiagnosticItemAd
 
   @Override
   public int getItemCount() {
-    return diags.size();
+    return diagnostics.size();
   }
 
   private int getDiagnosticIconId(DiagnosticItem diagnostic) {

app/src/main/java/com/itsaky/androidide/adapters/DiagnosticsAdapter.java

@@ -22,6 +22,7 @@ import android.graphics.PorterDuff;
 import android.view.LayoutInflater;
 import android.view.ViewGroup;
 
+import androidx.annotation.NonNull;
 import androidx.core.content.ContextCompat;
 import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
@@ -32,17 +33,19 @@ import com.itsaky.androidide.interfaces.DiagnosticClickListener;
 import com.itsaky.androidide.models.DiagnosticGroup;
 
 import java.util.List;
+import java.util.Objects;
 
 public class DiagnosticsAdapter extends RecyclerView.Adapter<DiagnosticsAdapter.VH> {
 
-  private final List<DiagnosticGroup> diags;
+  private final List<DiagnosticGroup> diagnostics;
   private final DiagnosticClickListener listener;
 
-  public DiagnosticsAdapter(List<DiagnosticGroup> diags, DiagnosticClickListener listener) {
-    this.diags = diags;
+  public DiagnosticsAdapter(List<DiagnosticGroup> diagnostics, DiagnosticClickListener listener) {
+    this.diagnostics = Objects.requireNonNull(diagnostics);
     this.listener = listener;
   }
 
+  @NonNull
   @Override
   public DiagnosticsAdapter.VH onCreateViewHolder(ViewGroup p1, int p2) {
     return new VH(
@@ -51,7 +54,7 @@ public class DiagnosticsAdapter extends RecyclerView.Adapter<DiagnosticsAdapter.
 
   @Override
   public void onBindViewHolder(DiagnosticsAdapter.VH p1, int p2) {
-    final DiagnosticGroup group = diags.get(p2);
+    final DiagnosticGroup group = diagnostics.get(p2);
     final LayoutDiagnosticGroupBinding binding = p1.binding;
 
     final int color =
@@ -77,7 +80,7 @@ public class DiagnosticsAdapter extends RecyclerView.Adapter<DiagnosticsAdapter.
 
   @Override
   public int getItemCount() {
-    return diags.size();
+    return diagnostics.size();
   }
 
   public class VH extends RecyclerView.ViewHolder {

app/src/main/java/com/itsaky/androidide/lsp/IDELanguageClientImpl.java

@@ -19,9 +19,10 @@
  */
 package com.itsaky.androidide.lsp;
 
-import android.os.Looper;
+import android.os.Trace;
 import android.view.View;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
 import com.blankj.utilcode.util.FileIOUtils;
@@ -57,10 +58,13 @@ import com.itsaky.toaster.Toaster;
 
 import java.io.File;
 import java.util.ArrayList;
+import java.util.Comparator;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Set;
+import java.util.TreeSet;
 import java.util.stream.Collectors;
 
 import io.github.rosemoe.sora.lang.diagnostic.DiagnosticsContainer;
@@ -75,6 +79,9 @@ public class IDELanguageClientImpl implements ILanguageClient {
   private final Map<File, List<DiagnosticItem>> diagnostics = new HashMap<>();
   protected EditorActivityProvider activityProvider;
 
+  public static final int MAX_DIAGNOSTIC_FILES = 10;
+  public static final int MAX_DIAGNOSTIC_ITEMS_PER_FILE = 20;
+
   private IDELanguageClientImpl(EditorActivityProvider provider) {
     setActivityProvider(provider);
   }
@@ -153,8 +160,7 @@ public class IDELanguageClientImpl implements ILanguageClient {
     File file = result.getFile().toFile();
     if (!file.exists() || !file.isFile()) return;
 
-    LOG.debug("Updating diagnostics. Is main thread?", Looper.getMainLooper() == Looper.myLooper());
-
+    Trace.beginSection("publishDiagnostics");
     final var editorView = activity().getEditorForFile(file);
     if (editorView != null) {
       final var editor = editorView.getEditor();
@@ -174,6 +180,7 @@ public class IDELanguageClientImpl implements ILanguageClient {
 
     diagnostics.put(file, result.getDiagnostics());
     activity().setDiagnosticsAdapter(newDiagnosticsAdapter());
+    Trace.endSection();
   }
 
   @Nullable
@@ -284,18 +291,81 @@ public class IDELanguageClientImpl implements ILanguageClient {
             });
   }
 
-  private List<DiagnosticGroup> mapAsGroup(Map<File, List<DiagnosticItem>> diags) {
-    List<DiagnosticGroup> groups = new ArrayList<>();
-    if (diags == null || diags.size() <= 0) return groups;
-    for (File file : diags.keySet()) {
-      var fileDiags = diags.get(file);
-      if (fileDiags == null || fileDiags.size() <= 0) continue;
-      DiagnosticGroup group = new DiagnosticGroup(R.drawable.ic_language_java, file, fileDiags);
+  private List<DiagnosticGroup> mapAsGroup(Map<File, List<DiagnosticItem>> map) {
+    final var groups = new ArrayList<DiagnosticGroup>();
+    var diagnosticMap = map;
+    if (diagnosticMap == null || diagnosticMap.size() <= 0) return groups;
+
+    if (diagnosticMap.size() > 10) {
+      LOG.warn("Limiting the diagnostics to 10 files");
+      diagnosticMap = filterRelevantDiagnostics(map);
+    }
+
+    for (File file : diagnosticMap.keySet()) {
+      var fileDiagnostics = diagnosticMap.get(file);
+      if (fileDiagnostics == null || fileDiagnostics.size() <= 0) continue;
+
+      // Trim the diagnostics list if we have too many diagnostic items.
+      // Including a lot of diagnostic items will result in UI lag when they are shown
+      if (fileDiagnostics.size() > MAX_DIAGNOSTIC_ITEMS_PER_FILE) {
+        LOG.warn(
+            "Limiting diagnostics to",
+            MAX_DIAGNOSTIC_ITEMS_PER_FILE,
+            "items for file",
+            file.getName());
+
+        fileDiagnostics = fileDiagnostics.subList(0, MAX_DIAGNOSTIC_ITEMS_PER_FILE);
+      }
+      DiagnosticGroup group =
+          new DiagnosticGroup(R.drawable.ic_language_java, file, fileDiagnostics);
       groups.add(group);
     }
     return groups;
   }
 
+  @NonNull
+  private Map<File, List<DiagnosticItem>> filterRelevantDiagnostics(
+      @NonNull final Map<File, List<DiagnosticItem>> map) {
+    final var result = new HashMap<File, List<DiagnosticItem>>();
+    final var files = map.keySet();
+
+    // Diagnostics of files that are open must always be included
+    final var relevantFiles = findOpenFiles(files, MAX_DIAGNOSTIC_FILES);
+
+    // If we can show a few more file diagnostics...
+    if (relevantFiles.size() < MAX_DIAGNOSTIC_FILES) {
+      final var alphabetical = new TreeSet<>(Comparator.comparing(File::getName));
+      alphabetical.addAll(files);
+      for (var file : alphabetical) {
+        relevantFiles.add(file);
+        if (relevantFiles.size() == MAX_DIAGNOSTIC_FILES) {
+          break;
+        }
+      }
+    }
+
+    for (var file : relevantFiles) {
+      result.put(file, map.get(file));
+    }
+    return result;
+  }
+
+  @NonNull
+  private Set<File> findOpenFiles(final Set<File> files, final int max) {
+    final var openedFiles = activity().getViewModel().getOpenedFiles();
+    final var result = new TreeSet<File>();
+    for (int i = 0; i < openedFiles.size(); i++) {
+      final var opened = openedFiles.get(i);
+      if (files.contains(opened)) {
+        result.add(opened);
+      }
+      if (result.size() == max) {
+        break;
+      }
+    }
+    return result;
+  }
+
   private void showAvailableQuickfixes(IDEEditor editor, List<CodeActionItem> actions) {
     final MaterialAlertDialogBuilder builder = DialogUtils.newMaterialDialogBuilder(activity());
     builder.setTitle(R.string.msg_code_actions);

app/src/main/java/com/itsaky/androidide/views/editor/IDEEditor.java

@@ -16,7 +16,6 @@
  */
 package com.itsaky.androidide.views.editor;
 
-import android.app.Activity;
 import android.app.Dialog;
 import android.app.ProgressDialog;
 import android.content.Context;
@@ -128,21 +127,21 @@ public class IDEEditor extends CodeEditor {
    * @param event The content change event.
    */
   private void handleContentChange(ContentChangeEvent event, Unsubscribe unsubscribe) {
-    if (getContext() instanceof Activity) {
-      ((Activity) getContext()).invalidateOptionsMenu();
-    }
-
     if (getFile() == null || mLanguageServer == null) {
       return;
     }
 
-    final var documentHandler = mLanguageServer.getDocumentHandler();
-    final var file = getFile().toPath();
-    if (documentHandler.accepts(file)) {
-      documentHandler.onContentChange(new DocumentChangeEvent(file, getText(), mFileVersion + 1));
-    }
+    CompletableFuture.runAsync(
+        () -> {
+          final var documentHandler = mLanguageServer.getDocumentHandler();
+          final var file = getFile().toPath();
+          if (documentHandler.accepts(file)) {
+            documentHandler.onContentChange(
+                new DocumentChangeEvent(file, getText(), mFileVersion + 1));
+          }
 
-    checkForSignatureHelp(event);
+          checkForSignatureHelp(event);
+        });
   }
 
   public static int createInputFlags() {
@@ -251,7 +250,6 @@ public class IDEEditor extends CodeEditor {
    * If any language server is set, requests signature help at the cursor's position. On a valid
    * response, shows the signature help in a popup window.
    */
-  @SuppressWarnings("unused") // accessed using reflection in CompletionItem class
   public void signatureHelp() {
     if (mLanguageServer != null && getFile() != null) {
       final CompletableFuture<SignatureHelp> future =

lsp/java/src/main/java/com/itsaky/lsp/java/JavaLanguageServer.java

@@ -17,6 +17,8 @@
 
 package com.itsaky.lsp.java;
 
+import android.os.Looper;
+
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.RestrictTo;
@@ -90,7 +92,12 @@ public class JavaLanguageServer implements ILanguageServer, IDocumentHandler {
     applySettings(getSettings());
   }
 
+  private void logIfMainThread(String methodName) {
+    LOG.debug(methodName, ": Is main thread?", Looper.myLooper() == Looper.getMainLooper());
+  }
+
   private void analyzeSelected() {
+    logIfMainThread("analyzeSelected");
     if (this.selectedFile == null) {
       return;
     }
@@ -129,6 +136,7 @@ public class JavaLanguageServer implements ILanguageServer, IDocumentHandler {
 
   @NonNull
   private JavaCompilerService createCompiler() {
+    logIfMainThread("createCompiler");
     return new JavaCompilerService(configuration.getClassPaths(), Collections.emptySet());
   }
 
@@ -197,6 +205,7 @@ public class JavaLanguageServer implements ILanguageServer, IDocumentHandler {
 
   @Override
   public void configurationChanged(Object newConfiguration) {
+    logIfMainThread("configurationChanged");
     if (!(newConfiguration instanceof JavaServerConfiguration)) {
       LOG.error("Invalid configuration passed to server.", newConfiguration);
       LOG.error("Configuration change event will be ignored.");
@@ -219,6 +228,7 @@ public class JavaLanguageServer implements ILanguageServer, IDocumentHandler {
   @NonNull
   @Override
   public ICompletionProvider getCompletionProvider() {
+    logIfMainThread("completionProvider");
     if (!settings.completionsEnabled()) {
       return new NoCompletionsProvider();
     }
@@ -260,6 +270,7 @@ public class JavaLanguageServer implements ILanguageServer, IDocumentHandler {
   @NonNull
   @Override
   public SignatureHelp signatureHelp(@NonNull SignatureHelpParams params) {
+    logIfMainThread("signatureHelp");
     if (!settings.signatureHelpEnabled()) {
       return new SignatureHelp(Collections.emptyList(), -1, -1);
     }
@@ -270,6 +281,7 @@ public class JavaLanguageServer implements ILanguageServer, IDocumentHandler {
   @NonNull
   @Override
   public List<DiagnosticItem> analyze(@NonNull Path file) {
+    logIfMainThread("analyze file:" + file);
     if (!settings.codeAnalysisEnabled()) {
       return Collections.emptyList();
     }
@@ -301,6 +313,7 @@ public class JavaLanguageServer implements ILanguageServer, IDocumentHandler {
 
   @Override
   public void onFileOpened(DocumentOpenEvent event) {
+    logIfMainThread("onFileOpened");
     onFileSelected(event.getOpenedFile());
     ensureAnalyzeTimerStarted();
     FileStore.open(event);
@@ -308,6 +321,7 @@ public class JavaLanguageServer implements ILanguageServer, IDocumentHandler {
 
   @Override
   public void onContentChange(@NonNull DocumentChangeEvent event) {
+    logIfMainThread("onContentChanged");
     // If a file's content is changed, it is definitely visible to user.
     onFileSelected(event.getChangedFile());
     ensureAnalyzeTimerStarted();
@@ -321,6 +335,7 @@ public class JavaLanguageServer implements ILanguageServer, IDocumentHandler {
 
   @Override
   public void onFileClosed(DocumentCloseEvent event) {
+    logIfMainThread("onFileClosed");
     FileStore.close(event);
   }
 
@@ -330,6 +345,7 @@ public class JavaLanguageServer implements ILanguageServer, IDocumentHandler {
   }
 
   private void ensureAnalyzeTimerStarted() {
+    logIfMainThread("ensureAnalyzeTimerStarted");
     if (!this.analyzeTimer.isStarted()) {
       this.analyzeTimer.start();
     } else {