DestroyDB API

Summary:
Expose DestroyDB API in RocksJava.
Closes https://github.com/facebook/rocksdb/pull/2934

Differential Revision: D5914775

Pulled By: sagar0

fbshipit-source-id: 84af6ea0d2bccdcfb9fe8c07b2f87373f0d5bab6

java/rocksjni/rocksjni.cc

@@ -2196,3 +2196,30 @@ void Java_org_rocksdb_RocksDB_ingestExternalFile(
     rocksdb::RocksDBExceptionJni::ThrowNew(env, s);
   }
 }
+
+/*
+ * Class:     org_rocksdb_RocksDB
+ * Method:    destroyDB
+ * Signature: (Ljava/lang/String;J)V
+ */
+void Java_org_rocksdb_RocksDB_destroyDB(
+    JNIEnv* env, jclass jcls, jstring jdb_path, jlong joptions_handle) {
+  const char* db_path = env->GetStringUTFChars(jdb_path, nullptr);
+  if(db_path == nullptr) {
+    // exception thrown: OutOfMemoryError
+    return;
+  }
+
+  auto* options = reinterpret_cast<rocksdb::Options*>(joptions_handle);
+  if (options == nullptr) {
+    rocksdb::RocksDBExceptionJni::ThrowNew(env,
+        rocksdb::Status::InvalidArgument("Invalid Options."));
+  }
+
+  rocksdb::Status s = rocksdb::DestroyDB(db_path, *options);
+  env->ReleaseStringUTFChars(jdb_path, db_path);
+
+  if (!s.ok()) {
+    rocksdb::RocksDBExceptionJni::ThrowNew(env, s);
+  }
+}

java/src/main/java/org/rocksdb/RocksDB.java

@@ -2174,6 +2174,21 @@ public class RocksDB extends RocksObject {
         filePathList.size(), ingestExternalFileOptions.nativeHandle_);
   }
 
+  /**
+   * Static method to destroy the contents of the specified database.
+   * Be very careful using this method.
+   *
+   * @param path the path to the Rocksdb database.
+   * @param options {@link org.rocksdb.Options} instance.
+   *
+   * @throws RocksDBException thrown if error happens in underlying
+   *    native library.
+   */
+  public static void destroyDB(final String path, final Options options)
+      throws RocksDBException {
+    destroyDB(path, options.nativeHandle_);
+  }
+
   /**
    * Private constructor.
    *
@@ -2380,5 +2395,7 @@ public class RocksDB extends RocksObject {
   private native void ingestExternalFile(long handle, long cfHandle,
       String[] filePathList, int filePathListLen,
       long ingest_external_file_options_handle) throws RocksDBException;
+  private native static void destroyDB(final String path,
+      final long optionsHandle) throws RocksDBException;
   protected DBOptionsInterface options_;
 }

java/src/test/java/org/rocksdb/RocksDBTest.java

@@ -763,4 +763,28 @@ public class RocksDBTest {
       }
     }
   }
+
+  @Test
+  public void destroyDB() throws RocksDBException {
+    try (final Options options = new Options().setCreateIfMissing(true)) {
+      String dbPath = dbFolder.getRoot().getAbsolutePath();
+      try (final RocksDB db = RocksDB.open(options, dbPath)) {
+        db.put("key1".getBytes(), "value".getBytes());
+      }
+      assertThat(dbFolder.getRoot().exists()).isTrue();
+      RocksDB.destroyDB(dbPath, options);
+      assertThat(dbFolder.getRoot().exists()).isFalse();
+    }
+  }
+
+  @Test(expected = RocksDBException.class)
+  public void destroyDBFailIfOpen() throws RocksDBException {
+    try (final Options options = new Options().setCreateIfMissing(true)) {
+      String dbPath = dbFolder.getRoot().getAbsolutePath();
+      try (final RocksDB db = RocksDB.open(options, dbPath)) {
+        // Fails as the db is open and locked.
+        RocksDB.destroyDB(dbPath, options);
+      }
+    }
+  }
 }