Fix indexing performance issue

If you open two source roots quickly, there's a "thrashing" effect where
each file added from the second root invalidates programCache and forces
the first root's error checking task to rebuild its program(s). When
this happens, error checking takes a long time: O(num files^2).

This can also happen if you delete many files from one root while
another root is error checking.

Fix this by adding/removing all indexables at once with the lock held.

src/netbeanstypescript/TSIndexerFactory.java

@@ -38,20 +38,24 @@
 package netbeanstypescript;
 
 import java.net.URL;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.logging.Level;
 import java.util.prefs.Preferences;
 import org.netbeans.api.progress.ProgressHandle;
 import org.netbeans.api.progress.ProgressHandleFactory;
 import org.netbeans.api.project.FileOwnerQuery;
 import org.netbeans.api.project.Project;
 import org.netbeans.api.project.ProjectUtils;
+import org.netbeans.modules.parsing.api.Snapshot;
 import org.netbeans.modules.parsing.api.Source;
 import org.netbeans.modules.parsing.spi.indexing.Context;
 import org.netbeans.modules.parsing.spi.indexing.CustomIndexer;
 import org.netbeans.modules.parsing.spi.indexing.CustomIndexerFactory;
 import org.netbeans.modules.parsing.spi.indexing.Indexable;
 import org.openide.filesystems.FileObject;
 import org.openide.filesystems.FileUtil;
+import org.openide.util.Pair;
 
 /**
  * This "indexer" doesn't really index anything, it's just a way to read all the TS files in a
@@ -78,15 +82,19 @@ protected void index(Iterable<? extends Indexable> files, Context context) {
                 if (root == null) {
                     return;
                 }
+                List<Pair<Indexable, Snapshot>> snapshots = new ArrayList<>();
                 for (Indexable indxbl: files) {
                     FileObject fo = root.getFileObject(indxbl.getRelativePath());
                     if (fo == null) continue;
                     if ("text/typescript".equals(FileUtil.getMIMEType(fo))) {
-                        TSService.addFile(Source.create(fo).createSnapshot(), indxbl, context);
+                        snapshots.add(Pair.of(indxbl, Source.create(fo).createSnapshot()));
                     } else if (fo.getNameExt().equals("tsconfig.json")) {
-                        TSService.addFile(Source.create(fo).createSnapshot(), indxbl, context);
+                        snapshots.add(Pair.of(indxbl, Source.create(fo).createSnapshot()));
                     }
                 }
+                if (! snapshots.isEmpty()) {
+                    TSService.addFiles(snapshots, context);
+                }
             }
         };
     }
@@ -105,9 +113,7 @@ public boolean supportsEmbeddedIndexers() {
 
     @Override
     public void filesDeleted(Iterable<? extends Indexable> deleted, Context context) {
-        for (Indexable i: deleted) {
-            TSService.removeFile(i, context);
-        }
+        TSService.removeFiles(deleted, context);
     }
 
     @Override

src/netbeanstypescript/TSService.java

@@ -73,6 +73,7 @@
 import org.openide.filesystems.FileUtil;
 import org.openide.filesystems.URLMapper;
 import org.openide.modules.InstalledFileLocator;
+import org.openide.util.Pair;
 import org.openide.util.RequestProcessor;
 
 /**
@@ -270,7 +271,7 @@ private static class FileData {
         String path;
     }
 
-    static void addFile(Snapshot snapshot, Indexable indxbl, Context cntxt) {
+    static void addFiles(List<Pair<Indexable, Snapshot>> files, Context cntxt) {
         lock.lock();
         try {
             URL rootURL = cntxt.getRootURI();
@@ -284,16 +285,18 @@ static void addFile(Snapshot snapshot, Indexable indxbl, Context cntxt) {
             }
             programs.put(rootURL, program);
 
-            FileData fi = new FileData();
-            fi.program = program;
-            fi.fileObject = snapshot.getSource().getFileObject();
-            fi.indexable = indxbl;
-            fi.path = fi.fileObject.getPath();
-            allFiles.put(fi.path, fi);
-
-            program.addFile(fi, snapshot, cntxt.checkForEditorModifications());
-            if (! cntxt.isAllFilesIndexing() && ! cntxt.checkForEditorModifications()) {
-                program.needCompileOnSave.add(fi.fileObject);
+            for (Pair<Indexable, Snapshot> item: files) {
+                FileData fi = new FileData();
+                fi.program = program;
+                fi.fileObject = item.second().getSource().getFileObject();
+                fi.indexable = item.first();
+                fi.path = fi.fileObject.getPath();
+                allFiles.put(fi.path, fi);
+
+                program.addFile(fi, item.second(), cntxt.checkForEditorModifications());
+                if (! cntxt.isAllFilesIndexing() && ! cntxt.checkForEditorModifications()) {
+                    program.needCompileOnSave.add(fi.fileObject);
+                }
             }
         } catch (Exception e) {
             throw new RuntimeException(e);
@@ -302,14 +305,16 @@ static void addFile(Snapshot snapshot, Indexable indxbl, Context cntxt) {
         }
     }
 
-    static void removeFile(Indexable indxbl, Context cntxt) {
+    static void removeFiles(Iterable<? extends Indexable> indxbls, Context cntxt) {
         lock.lock();
         try {
             ProgramData program = programs.get(cntxt.getRootURI());
             if (program != null) {
                 try {
-                    String path = program.removeFile(indxbl);
-                    allFiles.remove(path);
+                    for (Indexable indxbl: indxbls) {
+                        String path = program.removeFile(indxbl);
+                        allFiles.remove(path);
+                    }
                 } catch (Exception e) {
                     throw new RuntimeException(e);
                 }