Create MmapFileTest.java

test/random_access/src/test/java/seaewedfs/mmap/MmapFileTest.java

@@ -0,0 +1,143 @@
+package seaewedfs.mmap;
+
+import org.junit.Test;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.nio.MappedByteBuffer;
+import java.nio.channels.FileChannel;
+
+public class MmapFileTest {
+
+    File dir = new File("/Users/chris/tmp/mm/dev");
+
+    @Test
+    public void testMmap() {
+        try {
+            System.out.println("starting ...");
+
+            File f = new File(dir, "mmap_file.txt");
+            RandomAccessFile raf = new RandomAccessFile(f, "rw");
+            FileChannel fc = raf.getChannel();
+            MappedByteBuffer mbf = fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size());
+            fc.close();
+            raf.close();
+
+            FileOutputStream fos = new FileOutputStream(f);
+            fos.write("abcdefg".getBytes());
+            fos.close();
+            System.out.println("completed!");
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    @Test
+    public void testBigMmap() throws IOException {
+        /*
+
+// new file
+I0817 09:48:02 25175 dir.go:147] create /dev/mmap_big.txt: OpenReadWrite+OpenCreate
+I0817 09:48:02 25175 wfs.go:116] AcquireHandle /dev/mmap_big.txt uid=502 gid=20
+I0817 09:48:02 25175 file.go:62] file Attr /dev/mmap_big.txt, open:1, size: 0
+I0817 09:48:02 25175 meta_cache_subscribe.go:32] creating /dev/mmap_big.txt
+
+//get channel
+I0817 09:48:26 25175 file.go:62] file Attr /dev/mmap_big.txt, open:1, size: 0
+
+I0817 09:48:32 25175 file.go:62] file Attr /dev/mmap_big.txt, open:1, size: 0
+I0817 09:48:32 25175 wfs.go:116] AcquireHandle /dev/mmap_big.txt uid=0 gid=0
+I0817 09:48:32 25175 filehandle.go:160] Release /dev/mmap_big.txt fh 14968871991130164560
+
+//fileChannel.map
+I0817 09:49:18 25175 file.go:62] file Attr /dev/mmap_big.txt, open:1, size: 0
+I0817 09:49:18 25175 file.go:112] /dev/mmap_big.txt file setattr set size=262144 chunks=0
+I0817 09:49:18 25175 file.go:62] file Attr /dev/mmap_big.txt, open:1, size: 262144
+I0817 09:49:18 25175 file.go:62] file Attr /dev/mmap_big.txt, open:1, size: 262144
+I0817 09:49:18 25175 file.go:62] file Attr /dev/mmap_big.txt, open:1, size: 262144
+
+// buffer.put
+I0817 09:49:49 25175 filehandle.go:57] /dev/mmap_big.txt read fh 14968871991130164560: [0,32768) size 32768 resp.Data len=0 cap=32768
+I0817 09:49:49 25175 reader_at.go:113] zero2 [0,32768)
+I0817 09:49:50 25175 file.go:62] file Attr /dev/mmap_big.txt, open:1, size: 262144
+
+I0817 09:49:53 25175 file.go:233] /dev/mmap_big.txt fsync file Fsync [ID=0x4 Node=0xe Uid=0 Gid=0 Pid=0] Handle 0x2 Flags 1
+
+//close
+I0817 09:50:14 25175 file.go:62] file Attr /dev/mmap_big.txt, open:1, size: 262144
+I0817 09:50:14 25175 dirty_page.go:130] saveToStorage /dev/mmap_big.txt 1,315b69812039e5 [0,4096) of 262144 bytes
+I0817 09:50:14 25175 file.go:274] /dev/mmap_big.txt existing 0 chunks adds 1 more
+I0817 09:50:14 25175 filehandle.go:218] /dev/mmap_big.txt set chunks: 1
+I0817 09:50:14 25175 filehandle.go:220] /dev/mmap_big.txt chunks 0: 1,315b69812039e5 [0,4096)
+I0817 09:50:14 25175 meta_cache_subscribe.go:23] deleting /dev/mmap_big.txt
+I0817 09:50:14 25175 meta_cache_subscribe.go:32] creating /dev/mmap_big.txt
+
+// end of test
+I0817 09:50:41 25175 file.go:62] file Attr /dev/mmap_big.txt, open:1, size: 262144
+I0817 09:50:41 25175 filehandle.go:160] Release /dev/mmap_big.txt fh 14968871991130164560
+
+         */
+        // Create file object
+        File file = new File(dir, "mmap_big.txt");
+
+        try (RandomAccessFile randomAccessFile = new RandomAccessFile(file, "rw")) {
+            // Get file channel in read-write mode
+            FileChannel fileChannel = randomAccessFile.getChannel();
+
+            // Get direct byte buffer access using channel.map() operation
+            MappedByteBuffer buffer = fileChannel.map(FileChannel.MapMode.READ_WRITE, 0, 4096 * 8 * 8);
+
+            //Write the content using put methods
+            buffer.put("howtodoinjava.com".getBytes());
+        }
+
+/*
+> meta.cat /dev/mmap_big.txt
+{
+  "name": "mmap_big.txt",
+  "isDirectory": false,
+  "chunks": [
+    {
+      "fileId": "1,315b69812039e5",
+      "offset": "0",
+      "size": "4096",
+      "mtime": "1597683014026365000",
+      "eTag": "985ab0ac",
+      "sourceFileId": "",
+      "fid": {
+        "volumeId": 1,
+        "fileKey": "3234665",
+        "cookie": 2166372837
+      },
+      "sourceFid": null,
+      "cipherKey": null,
+      "isCompressed": true,
+      "isChunkManifest": false
+    }
+  ],
+  "attributes": {
+    "fileSize": "262144",
+    "mtime": "1597683014",
+    "fileMode": 420,
+    "uid": 502,
+    "gid": 20,
+    "crtime": "1597682882",
+    "mime": "application/octet-stream",
+    "replication": "",
+    "collection": "",
+    "ttlSec": 0,
+    "userName": "",
+    "groupName": [
+    ],
+    "symlinkTarget": "",
+    "md5": null
+  },
+  "extended": {
+  }
+}
+ */
+
+    }
+}