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 import org.slf4j.Logger;
  23 import org.slf4j.LoggerFactory;
  24
  25 public class FileIO {
  26
  27     private static final Logger LOGGER = LoggerFactory.getLogger(FileIO.class);
  28     private static final FileAttribute<?>[] NO_ATTRIBUTES = new FileAttribute[0];
  29
  30     private static final Set<OpenOption> CREATE_OPTIONS = new HashSet<>(2);
  31     private static final Set<OpenOption> APPEND_OPTIONS = new HashSet<>(1);
  32
  33     static {
  34         CREATE_OPTIONS.add(StandardOpenOption.WRITE);
  35         CREATE_OPTIONS.add(StandardOpenOption.CREATE);
  36
  37         APPEND_OPTIONS.add(StandardOpenOption.APPEND);
  38     }
  39
  40         private Path path;
  41         private int writePosition = 0;
  42
  43         private FileIO(Path path) {
  44                 this.path = path;
  45         }
  46
  47         private static Map<Path, FileIO> map = new HashMap<Path, FileIO>();
  48
  49         public static FileIO get(Path path) {
  50                 synchronized(map) {
  51                         FileIO existing = map.get(path);
  52                         if(existing == null) {
  53                                 existing = new FileIO(path);
  54                                 map.put(path, existing);
  55                         }
  56                         return existing;
  57                 }
  58         }
  59
  60         //private static final boolean TRACE_SWAP = false;
  61         private static final boolean TRACE_PERF = false;
  62
  63         public synchronized int saveBytes(byte[] bytes, int length, boolean overwrite) throws IOException {
  64                 if(overwrite) writePosition = 0;
  65                 int result = writePosition;
  66                 long start = System.nanoTime();
  67                 Set<OpenOption> options = writePosition == 0 ? CREATE_OPTIONS : APPEND_OPTIONS;
  68
  69                 ByteBuffer bb = ByteBuffer.wrap(bytes, 0, length);
  70                 try (FileChannel fc = FileChannel.open(path, options, NO_ATTRIBUTES)) {
  71             fc.write(bb);
  72
  73             writePosition += length;
  74             if(TRACE_PERF) {
  75                 long duration = System.nanoTime()-start;
  76                 double ds = 1e-9*duration;
  77                 LOGGER.info("Wrote " + bytes.length + " bytes @ " + 1e-6*bytes.length / ds + "MB/s");
  78             }
  79             return result;
  80                 } catch (Throwable t) {
  81                     throw new IOException("An error occured file saving bytes for file " + path.toAbsolutePath().toString(), t);
  82                 }
  83         }
  84
  85     public synchronized byte[] readBytes(int offset, int length) throws IOException {
  86         long start = System.nanoTime();
  87         try (SeekableByteChannel channel = Files.newByteChannel(path)) {
  88             channel.position(offset);
  89             ByteBuffer buf = ByteBuffer.allocate(length);
  90             int read = 0;
  91             while (read < length) {
  92                 read += channel.read(buf);
  93             }
  94             byte[] result = buf.array();
  95             if (result.length != length)
  96                 LOGGER.info("result length does not match expected {} {} {}", this, result.length, length);
  97             if (TRACE_PERF) {
  98                 long duration = System.nanoTime() - start;
  99                 double ds = 1e-9 * duration;
 100                 LOGGER.info("Read " + result.length + " bytes @ " + 1e-6 * result.length / ds + "MB/s");
 101             }
 102             return result;
 103         }
 104     }
 105
 106         public static void syncPath(Path f) throws IOException {
 107                 // Does not seem to need 's' according to unit test in Windows
 108                 try (RandomAccessFile raf = new RandomAccessFile(f.toFile(), "rw")) {
 109                         raf.getFD().sync();
 110                 }
 111         }
 112
 113         static void uncheckedSyncPath(Path f) {
 114                 try {
 115                         syncPath(f);
 116                 } catch (IOException e) {
 117                         throw new RuntimeIOException(e);
 118                 }
 119         }
 120
 121         public static void main(String[] args) throws Exception {
 122
 123                 byte[] buf = new byte[1024*1024];
 124
 125                 long s = System.nanoTime();
 126
 127                 Path test = Paths.get("e:/work/test.dat");
 128                 OutputStream fs = Files.newOutputStream(test);
 129                 OutputStream os = new BufferedOutputStream(fs, 128*1024);
 130
 131                 for(int i=0;i<40;i++) {
 132                         os.write(buf);
 133                 }
 134
 135                 os.flush();
 136                 //fs.getFD().sync();
 137                 os.close();
 138
 139                 syncPath(test);
 140
 141                 if (LOGGER.isDebugEnabled()) {
 142                 long duration = System.nanoTime()-s;
 143                 LOGGER.info("Took " + 1e-6*duration + "ms.");
 144                 }
 145         }
 146
 147 }