Adds a function to RocksJava for retrieving the version (#7083)

Summary:
Adds the function `RocksDB#rocksdbVersion()` for retrieving the RocksDB version.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7083

Reviewed By: cheng-chang

Differential Revision: D22391628

Pulled By: pdillinger

fbshipit-source-id: e1cabcf28aa81f5ee8dcdce5c9eca6b3155a279e

java/rocksjni/rocksjni.cc

@@ -9,6 +9,7 @@
 #include <jni.h>
 #include <stdio.h>
 #include <stdlib.h>
+
 #include <algorithm>
 #include <functional>
 #include <memory>
@@ -22,6 +23,7 @@
 #include "rocksdb/db.h"
 #include "rocksdb/options.h"
 #include "rocksdb/types.h"
+#include "rocksdb/version.h"
 #include "rocksjni/portal.h"
 
 #ifdef min
@@ -2821,7 +2823,7 @@ jlong Java_org_rocksdb_RocksDB_getLatestSequenceNumber(
  * Method:    setPreserveDeletesSequenceNumber
  * Signature: (JJ)Z
  */
-jboolean JNICALL Java_org_rocksdb_RocksDB_setPreserveDeletesSequenceNumber(
+jboolean Java_org_rocksdb_RocksDB_setPreserveDeletesSequenceNumber(
     JNIEnv*, jobject, jlong jdb_handle, jlong jseq_number) {
   auto* db = reinterpret_cast<ROCKSDB_NAMESPACE::DB*>(jdb_handle);
   if (db->SetPreserveDeletesSequenceNumber(
@@ -3310,8 +3312,7 @@ void Java_org_rocksdb_RocksDB_startTrace(
  * Method:    endTrace
  * Signature: (J)V
  */
-JNIEXPORT void JNICALL Java_org_rocksdb_RocksDB_endTrace(
-    JNIEnv* env, jobject, jlong jdb_handle) {
+void Java_org_rocksdb_RocksDB_endTrace(JNIEnv* env, jobject, jlong jdb_handle) {
   auto* db = reinterpret_cast<ROCKSDB_NAMESPACE::DB*>(jdb_handle);
   auto s = db->EndTrace();
   if (!s.ok()) {
@@ -3379,9 +3380,11 @@ bool get_slice_helper(JNIEnv* env, jobjectArray ranges, jsize index,
  * Method:    deleteFilesInRanges
  * Signature: (JJLjava/util/List;Z)V
  */
-JNIEXPORT void JNICALL Java_org_rocksdb_RocksDB_deleteFilesInRanges(
-    JNIEnv* env, jobject /*jdb*/, jlong jdb_handle, jlong jcf_handle,
-    jobjectArray ranges, jboolean include_end) {
+void Java_org_rocksdb_RocksDB_deleteFilesInRanges(JNIEnv* env, jobject /*jdb*/,
+                                                  jlong jdb_handle,
+                                                  jlong jcf_handle,
+                                                  jobjectArray ranges,
+                                                  jboolean include_end) {
   jsize length = env->GetArrayLength(ranges);
 
   std::vector<ROCKSDB_NAMESPACE::RangePtr> rangesVector;
@@ -3416,3 +3419,15 @@ JNIEXPORT void JNICALL Java_org_rocksdb_RocksDB_deleteFilesInRanges(
     ROCKSDB_NAMESPACE::RocksDBExceptionJni::ThrowNew(env, s);
   }
 }
+
+/*
+ * Class:     org_rocksdb_RocksDB
+ * Method:    version
+ * Signature: ()I
+ */
+jint Java_org_rocksdb_RocksDB_version(JNIEnv*, jclass) {
+  uint32_t encodedVersion = (ROCKSDB_MAJOR & 0xff) << 16;
+  encodedVersion |= (ROCKSDB_MINOR & 0xff) << 8;
+  encodedVersion |= (ROCKSDB_PATCH & 0xff);
+  return static_cast<jint>(encodedVersion);
+}

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

@@ -59,18 +59,21 @@ public class RocksDB extends RocksObject {
           if (compressionType.getLibraryName() != null) {
             System.loadLibrary(compressionType.getLibraryName());
           }
-        } catch (UnsatisfiedLinkError e) {
+        } catch (final UnsatisfiedLinkError e) {
           // since it may be optional, we ignore its loading failure here.
         }
       }
       try {
         NativeLibraryLoader.getInstance().loadLibrary(tmpDir);
-      } catch (IOException e) {
+      } catch (final IOException e) {
         libraryLoaded.set(LibraryState.NOT_LOADED);
         throw new RuntimeException("Unable to load the RocksDB shared library",
             e);
       }
 
+      final int encodedVersion = version();
+      version = Version.fromEncodedVersion(encodedVersion);
+
       libraryLoaded.set(LibraryState.LOADED);
       return;
     }
@@ -107,7 +110,7 @@ public class RocksDB extends RocksObject {
             System.load(path + "/" + Environment.getSharedLibraryFileName(
                 compressionType.getLibraryName()));
             break;
-          } catch (UnsatisfiedLinkError e) {
+          } catch (final UnsatisfiedLinkError e) {
             // since they are optional, we ignore loading fails.
           }
         }
@@ -120,7 +123,7 @@ public class RocksDB extends RocksObject {
               Environment.getJniLibraryFileName("rocksdbjni"));
           success = true;
           break;
-        } catch (UnsatisfiedLinkError e) {
+        } catch (final UnsatisfiedLinkError e) {
           err = e;
         }
       }
@@ -129,6 +132,9 @@ public class RocksDB extends RocksObject {
         throw err;
       }
 
+      final int encodedVersion = version();
+      version = Version.fromEncodedVersion(encodedVersion);
+
       libraryLoaded.set(LibraryState.LOADED);
       return;
     }
@@ -142,6 +148,10 @@ public class RocksDB extends RocksObject {
     }
   }
 
+  public static Version rocksdbVersion() {
+    return version;
+  }
+
   /**
    * Private constructor.
    *
@@ -4531,5 +4541,47 @@ public class RocksDB extends RocksObject {
   private native static void destroyDB(final String path,
       final long optionsHandle) throws RocksDBException;
 
+  private native static int version();
+
   protected DBOptionsInterface options_;
+  private static Version version;
+
+  public static class Version {
+    private final byte major;
+    private final byte minor;
+    private final byte patch;
+
+    public Version(final byte major, final byte minor, final byte patch) {
+      this.major = major;
+      this.minor = minor;
+      this.patch = patch;
+    }
+
+    public int getMajor() {
+      return major;
+    }
+
+    public int getMinor() {
+      return minor;
+    }
+
+    public int getPatch() {
+      return patch;
+    }
+
+    @Override
+    public String toString() {
+      return getMajor() + "." + getMinor() + "." + getPatch();
+    }
+
+    private static Version fromEncodedVersion(int encodedVersion) {
+      final byte patch = (byte) (encodedVersion & 0xff);
+      encodedVersion >>= 8;
+      final byte minor = (byte) (encodedVersion & 0xff);
+      encodedVersion >>= 8;
+      final byte major = (byte) (encodedVersion & 0xff);
+
+      return new Version(major, minor, patch);
+    }
+  }
 }

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

@@ -1683,6 +1683,13 @@ public class RocksDBTest {
     }
   }
 
+  @Test
+  public void rocksdbVersion() {
+    final RocksDB.Version version = RocksDB.rocksdbVersion();
+    assertThat(version).isNotNull();
+    assertThat(version.getMajor()).isGreaterThan(1);
+  }
+
   private static class InMemoryTraceWriter extends AbstractTraceWriter {
     private final List<byte[]> writes = new ArrayList<>();
     private volatile boolean closed = false;