Implement isolated Build and Refresh with immutable leased snapshots

designer-intellij/src/main/java/de/neitzel/fxdesigner/intellij/IntellijDocuments.java

@@ -90,6 +90,26 @@ public final class IntellijDocuments implements HostServices.Documents, AutoClos
         });
   }
 
+  public CompletionStage<List<DocumentSnapshot>> unsaved() {
+    return edt(
+        () -> {
+          var result = new ArrayList<DocumentSnapshot>();
+          var manager = FileDocumentManager.getInstance();
+          for (var document : manager.getUnsavedDocuments()) {
+            var file = manager.getFile(document);
+            if (file == null || !file.isInLocalFileSystem()) continue;
+            var handle =
+                (Handle) open(Path.of(file.getPath()).toUri()).toCompletableFuture().join();
+            try {
+              result.add(snapshot(handle.s));
+            } finally {
+              handle.release();
+            }
+          }
+          return List.copyOf(result);
+        });
+  }
+
   private DocumentSnapshot snapshot(State s) {
     return new DocumentSnapshot(
         Path.of(s.file.getPath()).toUri(),
@@ -171,7 +191,13 @@ public final class IntellijDocuments implements HostServices.Documents, AutoClos
             if (!s.document.isWritable() || !s.file.isWritable())
               throw new IllegalStateException("Read-only document");
             Path file = Path.of(s.file.getPath());
-            if (!Files.readString(file).equals(s.disk))
+            String onDisk = Files.readString(file);
+            if (!FileDocumentManager.getInstance().isDocumentUnsaved(s.document)
+                && onDisk.equals(s.document.getText())) {
+              s.disk = onDisk;
+              return IntellijDocuments.this.snapshot(s);
+            }
+            if (!onDisk.equals(s.disk))
               throw new ConcurrentModificationException("External change; draft retained");
             FileDocumentManager.getInstance().saveDocument(s.document);
             if (FileDocumentManager.getInstance().isDocumentUnsaved(s.document))

designer-intellij/src/test/java/de/neitzel/fxdesigner/intellij/BuildInputInventoryTest.java

@@ -0,0 +1,35 @@
+package de.neitzel.fxdesigner.intellij;
+
+import com.intellij.openapi.command.WriteCommandAction;
+import com.intellij.openapi.fileEditor.FileDocumentManager;
+import com.intellij.openapi.vfs.LocalFileSystem;
+import com.intellij.openapi.vfs.newvfs.impl.VfsRootAccess;
+import com.intellij.testFramework.fixtures.BasePlatformTestCase;
+import java.nio.file.*;
+
+public final class BuildInputInventoryTest extends BasePlatformTestCase {
+  public void testNativeJavaDraftInventoryAndAutosaveBeforeExplicitSave() throws Exception {
+    Path file = Files.createTempFile("designer-build-input-", ".java").toRealPath();
+    Files.writeString(file, "class Original {}");
+    VfsRootAccess.allowRootAccess(getTestRootDisposable(), file.toString());
+    try (var documents = new IntellijDocuments(getProject())) {
+      var virtual = LocalFileSystem.getInstance().refreshAndFindFileByNioFile(file);
+      var nativeDocument = FileDocumentManager.getInstance().getDocument(virtual);
+      WriteCommandAction.runWriteCommandAction(
+          getProject(), () -> nativeDocument.setText("class Edited {}"));
+      var draft =
+          documents.unsaved().toCompletableFuture().get().stream()
+              .filter(d -> d.document().equals(file.toUri()))
+              .findFirst()
+              .orElseThrow();
+      assertTrue(draft.dirty());
+      FileDocumentManager.getInstance().saveDocument(nativeDocument);
+      try (var handle = documents.open(file.toUri()).toCompletableFuture().get()) {
+        assertFalse(handle.save(draft.revision()).toCompletableFuture().get().dirty());
+      }
+      assertEquals("class Edited {}", Files.readString(file));
+    } finally {
+      Files.deleteIfExists(file);
+    }
+  }
+}