bundles/org.simantics.acorn/src/org/simantics/acorn/FileIO.java

   1 package org.simantics.acorn;
   2
   3 import java.io.BufferedOutputStream;
   4 import java.io.IOException;
   5 import java.io.OutputStream;
   6 import java.io.RandomAccessFile;
   7 import java.nio.ByteBuffer;
   8 import java.nio.channels.FileChannel;
   9 import java.nio.channels.SeekableByteChannel;
  10 import java.nio.file.Files;
  11 import java.nio.file.OpenOption;
  12 import java.nio.file.Path;
  13 import java.nio.file.Paths;
  14 import java.nio.file.StandardOpenOption;
  15 import java.nio.file.attribute.FileAttribute;
  16 import java.util.HashMap;
  17 import java.util.HashSet;
  18 import java.util.Map;
  19 import java.util.Set;
  20
  21 import org.simantics.databoard.file.RuntimeIOException;
  22
  23 public class FileIO {
  24
  25     private static final FileAttribute<?>[] NO_ATTRIBUTES = new FileAttribute[0];
  26
  27     private static final Set<OpenOption> CREATE_OPTIONS = new HashSet<>(2);
  28     private static final Set<OpenOption> APPEND_OPTIONS = new HashSet<>(1);
  29
  30     static {
  31         CREATE_OPTIONS.add(StandardOpenOption.WRITE);
  32         CREATE_OPTIONS.add(StandardOpenOption.CREATE);
  33
  34         APPEND_OPTIONS.add(StandardOpenOption.APPEND);
  35     }
  36
  37         private Path path;
  38         private int writePosition = 0;
  39
  40         private FileIO(Path path) {
  41                 this.path = path;
  42         }
  43
  44         private static Map<Path, FileIO> map = new HashMap<Path, FileIO>();
  45
  46         public static FileIO get(Path path) {
  47                 synchronized(map) {
  48                         FileIO existing = map.get(path);
  49                         if(existing == null) {
  50                                 existing = new FileIO(path);
  51                                 map.put(path, existing);
  52                         }
  53                         return existing;
  54                 }
  55         }
  56
  57         //private static final boolean TRACE_SWAP = false;
  58         private static final boolean TRACE_PERF = false;
  59
  60         public synchronized int saveBytes(byte[] bytes, int length, boolean overwrite) throws IOException {
  61                 if(overwrite) writePosition = 0;
  62                 int result = writePosition;
  63                 long start = System.nanoTime();
  64                 Set<OpenOption> options = writePosition == 0 ? CREATE_OPTIONS : APPEND_OPTIONS;
  65
  66                 ByteBuffer bb = ByteBuffer.wrap(bytes, 0, length);
  67                 try (FileChannel fc = FileChannel.open(path, options, NO_ATTRIBUTES)) {
  68             fc.write(bb);
  69
  70             writePosition += length;
  71             if(TRACE_PERF) {
  72                 long duration = System.nanoTime()-start;
  73                 double ds = 1e-9*duration;
  74                 System.err.println("Wrote " + bytes.length + " bytes @ " + 1e-6*bytes.length / ds + "MB/s");
  75             }
  76             return result;
  77                 } catch (Throwable t) {
  78                     throw new IOException("An error occured file saving bytes for file " + path.toAbsolutePath().toString(), t);
  79                 }
  80         }
  81
  82     public synchronized byte[] readBytes(int offset, int length) throws IOException {
  83         long start = System.nanoTime();
  84         try (SeekableByteChannel channel = Files.newByteChannel(path)) {
  85             channel.position(offset);
  86             ByteBuffer buf = ByteBuffer.allocate(length);
  87             int read = 0;
  88             while (read < length) {
  89                 read += channel.read(buf);
  90             }
  91             byte[] result = buf.array();
  92             if (result.length != length)
  93                 System.err.println("faa");
  94             if (TRACE_PERF) {
  95                 long duration = System.nanoTime() - start;
  96                 double ds = 1e-9 * duration;
  97                 System.err.println("Read " + result.length + " bytes @ " + 1e-6 * result.length / ds + "MB/s");
  98             }
  99             return result;
 100         }
 101     }
 102
 103         public static void syncPath(Path f) throws IOException {
 104                 // Does not seem to need 's' according to unit test in Windows
 105                 try (RandomAccessFile raf = new RandomAccessFile(f.toFile(), "rw")) {
 106                         raf.getFD().sync();
 107                 }
 108         }
 109
 110         static void uncheckedSyncPath(Path f) {
 111                 try {
 112                         syncPath(f);
 113                 } catch (IOException e) {
 114                         throw new RuntimeIOException(e);
 115                 }
 116         }
 117
 118         public static void main(String[] args) throws Exception {
 119
 120                 byte[] buf = new byte[1024*1024];
 121
 122                 long s = System.nanoTime();
 123
 124                 Path test = Paths.get("e:/work/test.dat");
 125                 OutputStream fs = Files.newOutputStream(test);
 126                 OutputStream os = new BufferedOutputStream(fs, 128*1024);
 127
 128                 for(int i=0;i<40;i++) {
 129                         os.write(buf);
 130                 }
 131
 132                 os.flush();
 133                 //fs.getFD().sync();
 134                 os.close();
 135
 136                 syncPath(test);
 137
 138                 long duration = System.nanoTime()-s;
 139                 System.err.println("Took " + 1e-6*duration + "ms.");
 140
 141
 142         }
 143
 144 }