Report manifest and state differences

bosk-mongo/src/main/java/io/vena/bosk/drivers/mongo/AbstractFormatDriver.java

@@ -3,11 +3,14 @@
 import io.vena.bosk.MapValue;
 import io.vena.bosk.RootReference;
 import io.vena.bosk.StateTreeNode;
+import io.vena.bosk.drivers.mongo.status.BsonComparator;
 import io.vena.bosk.drivers.mongo.status.MongoStatus;
+import io.vena.bosk.drivers.mongo.status.StateStatus;
 import java.io.IOException;
 import lombok.RequiredArgsConstructor;
 import org.bson.BsonDocument;
 import org.bson.BsonInt64;
+import org.bson.BsonValue;
 
 import static io.vena.bosk.drivers.mongo.Formatter.REVISION_ZERO;
 
@@ -19,11 +22,18 @@ abstract class AbstractFormatDriver<R extends StateTreeNode> implements FormatDr
 	@Override
 	public MongoStatus readStatus() {
 		try {
-			BsonState bsonState = loadBsonState();
+			BsonState dbContents = loadBsonState();
+			BsonDocument loadedBsonState = dbContents.state;
+			BsonValue inMemoryState = formatter.object2bsonValue(rootRef.value(), rootRef.targetType());
+			BsonComparator comp = new BsonComparator();
 			return new MongoStatus(
 				null,
 				null, // MainDriver should fill this in
-				formatter.bsonValueBinarySize(bsonState.state)
+				new StateStatus(
+					dbContents.revision.longValue(),
+					formatter.bsonValueBinarySize(loadedBsonState),
+					comp.difference(inMemoryState, loadedBsonState)
+				)
 			);
 		} catch (UninitializedCollectionException e) {
 			return new MongoStatus(
@@ -64,4 +74,5 @@ record BsonState(
 		BsonInt64 revision,
 		BsonDocument diagnosticAttributes
 	){}
+
 }

bosk-mongo/src/main/java/io/vena/bosk/drivers/mongo/MainDriver.java

@@ -335,16 +335,13 @@ public void refurbish() throws IOException {
 
 	@Override
 	public MongoStatus readStatus() throws Exception {
-		try (var __ = collection.newReadOnlySession()) {
-			FormatDriver<R> detectedDriver = detectFormat();
-			MongoStatus partialResult = detectedDriver.readStatus();
+		try (
+			var __1 = bosk.readContext();
+			var __2 = collection.newReadOnlySession()
+		) {
+			MongoStatus partialResult = detectFormat().readStatus();
 			Manifest manifest = loadManifest(); // TODO: Avoid loading the manifest again
-
-			return new MongoStatus(
-				partialResult.error(),
-				manifest,
-				partialResult.stateBytes()
-			);
+			return partialResult.with(driverSettings.preferredDatabaseFormat(), manifest);
 		}
 	}
 

bosk-mongo/src/main/java/io/vena/bosk/drivers/mongo/Manifest.java

@@ -1,6 +1,7 @@
 package io.vena.bosk.drivers.mongo;
 
 import io.vena.bosk.StateTreeNode;
+import io.vena.bosk.drivers.mongo.MongoDriverSettings.DatabaseFormat;
 import java.util.Optional;
 
 public record Manifest(
@@ -17,4 +18,13 @@ public static Manifest forSequoia() {
 	public static Manifest forPando(PandoFormat settings) {
 		return new Manifest(1, Optional.empty(), Optional.of(settings));
 	}
+
+	public static Manifest forFormat(DatabaseFormat format) {
+		// TODO: Use a type switch in newer Java versions
+		if (format instanceof PandoFormat p) {
+			return forPando(p);
+		} else {
+			return forSequoia();
+		}
+	}
 }

bosk-mongo/src/main/java/io/vena/bosk/drivers/mongo/status/ManifestStatus.java

@@ -0,0 +1,12 @@
+package io.vena.bosk.drivers.mongo.status;
+
+import io.vena.bosk.drivers.mongo.Manifest;
+
+public record ManifestStatus(
+	Manifest expected,
+	Manifest actual
+) {
+	public boolean isIdentical() {
+		return expected.equals(actual);
+	}
+}

bosk-mongo/src/main/java/io/vena/bosk/drivers/mongo/status/MongoStatus.java

@@ -10,6 +10,22 @@
  */
 public record MongoStatus(
 	@JsonInclude(NON_NULL) String error,
-	Manifest manifest,
-	Long stateBytes
-) { }
+	ManifestStatus manifest,
+	StateStatus state
+) {
+	public MongoStatus with(MongoDriverSettings.DatabaseFormat preferredFormat, Manifest actualManifest) {
+		return new MongoStatus(
+			this.error,
+			new ManifestStatus(
+				Manifest.forFormat(preferredFormat),
+				actualManifest
+			),
+			this.state
+		);
+	}
+
+	public boolean isAllClear() {
+		return manifest.isIdentical()
+			&& state.difference() instanceof NoDifference;
+	}
+}

bosk-mongo/src/main/java/io/vena/bosk/drivers/mongo/status/StateStatus.java

@@ -0,0 +1,7 @@
+package io.vena.bosk.drivers.mongo.status;
+
+public record StateStatus(
+	Long revision,
+	Long sizeInBytes,
+	Difference difference
+) { }