[indexes] extracted statistics access interface for BlobStorage

GitOrigin-RevId: c67e4d95318d0b9f7a0392d9b432da4240b2e57b

platform/platform-impl/src/com/intellij/openapi/vfs/newvfs/persistent/dev/blobstorage/StreamlinedBlobStorageHelper.java

@@ -1,4 +1,4 @@
-// Copyright 2000-2023 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+// Copyright 2000-2024 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package com.intellij.openapi.vfs.newvfs.persistent.dev.blobstorage;
 
 import com.intellij.openapi.util.IntRef;
@@ -8,10 +8,7 @@ import com.intellij.platform.diagnostic.telemetry.TelemetryManager;
 import com.intellij.util.io.ClosedStorageException;
 import com.intellij.util.io.CorruptedException;
 import com.intellij.util.io.IOUtil;
-import com.intellij.util.io.blobstorage.ByteBufferReader;
-import com.intellij.util.io.blobstorage.ByteBufferWriter;
-import com.intellij.util.io.blobstorage.SpaceAllocationStrategy;
-import com.intellij.util.io.blobstorage.StreamlinedBlobStorage;
+import com.intellij.util.io.blobstorage.*;
 import io.opentelemetry.api.common.Attributes;
 import io.opentelemetry.api.metrics.BatchCallback;
 import io.opentelemetry.api.metrics.Meter;
@@ -39,7 +36,7 @@ import static com.intellij.platform.diagnostic.telemetry.PlatformScopesKt.Storag
  * of responsibilities -- i.e. extracting all storage-specific functionality under common interface,
  * and implement adapters for different storages.
  */
-public abstract class StreamlinedBlobStorageHelper implements StreamlinedBlobStorage {
+public abstract class StreamlinedBlobStorageHelper implements StreamlinedBlobStorage, BlobStorageStatistics {
 
   /** First header int32, used to recognize this storage's file type */
   protected static final int MAGIC_WORD = IOUtil.asciiToMagicWord("SBlS");
@@ -260,22 +257,27 @@ public abstract class StreamlinedBlobStorageHelper implements StreamlinedBlobSto
     return recordsAllocated.get() - recordsDeleted.get() - recordsRelocated.get();
   }
 
+  @Override
   public int recordsAllocated() {
     return recordsAllocated.get();
   }
 
+  @Override
   public int recordsRelocated() {
     return recordsRelocated.get();
   }
 
+  @Override
   public int recordsDeleted() {
     return recordsDeleted.get();
   }
 
+  @Override
   public long totalLiveRecordsPayloadBytes() {
     return totalLiveRecordsPayloadBytes.get();
   }
 
+  @Override
   public long totalLiveRecordsCapacityBytes() {
     return totalLiveRecordsCapacityBytes.get();
   }

platform/util/src/com/intellij/util/io/blobstorage/BlobStorageStatistics.java

@@ -0,0 +1,38 @@
+// Copyright 2000-2024 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.util.io.blobstorage;
+
+import org.jetbrains.annotations.ApiStatus;
+
+/**
+ * Provides access to storage internal statistics.
+ * If storage provides access to such a statistics -- it must implement this interface
+ */
+@ApiStatus.Internal
+public interface BlobStorageStatistics {
+
+  /** records currently alive (=allocated-relocated-deleted) */
+  int liveRecordsCount();
+
+  /** records allocated since storage creation (including deleted/relocated) */
+  int recordsAllocated();
+
+  /** records re-allocated -- i.e. recordId is accessible, but the access redirects to another (actual) record */
+  int recordsRelocated();
+
+  /** records deleted, i.e. un-accessible anymore */
+  int recordsDeleted();
+
+
+  /**
+   * Total size (bytes) occupied by storage data.
+   * Includes all the overhead of file/records header, alignment, etc.
+   * Could be <= file size, if e.g. file is expanded in advance.
+   */
+  long sizeInBytes();
+
+  /** Total size of all alive records' payload, i.e. 'useful size', without any overhead */
+  long totalLiveRecordsPayloadBytes();
+
+  /** Total size of all alive records' capacity */
+  long totalLiveRecordsCapacityBytes();
+}