synced extra data provided by ASAPPeer. Use it e.g. to keep a hubList in SharkPeer

Author: thsc42

src/net/sharksystem/asap/ASAPInternalPeerWrapper.java

@@ -91,4 +91,24 @@ public void notifyOnlinePeersChanged(ASAPInternalPeer peer) {
     public void notifyOnlinePeersChanged(Set<CharSequence> peerList) {
         this.environmentChangesListenerManager.notifyListeners(peerList);
     }
+
+
+    /**
+     * Make a value persistent with key
+     * @param key
+     * @param value
+     */
+    public void putExtra(CharSequence key, byte[] value) throws IOException, ASAPException {
+        this.peer.putExtra(key, value);
+    }
+
+    /**
+     * Return a value. Throws an exception if not set
+     * @param key
+     * @throws ASAPException key never used in putExtra
+     */
+    public byte[] getExtra(CharSequence key) throws ASAPException, IOException {
+        return this.peer.getExtra(key);
+    }
+
 }

src/net/sharksystem/asap/ASAPPeer.java

@@ -52,4 +52,19 @@ void setASAPRoutingAllowed(CharSequence applicationFormat, boolean allowed)
      */
     ASAPConnection handleConnection(InputStream is, OutputStream os, boolean encrypt, boolean sign,
                                     EncounterConnectionType connectionType) throws IOException, ASAPException;
+
+
+    /**
+     * Make a value persistent with key
+     * @param key
+     * @param value
+     */
+    void putExtra(CharSequence key, byte[] value) throws IOException, ASAPException;
+
+    /**
+     * Return a value. Throws an exception if not set
+     * @param key
+     * @throws ASAPException key never used in putExtra
+     */
+    byte[] getExtra(CharSequence key) throws ASAPException, IOException;
 }

src/net/sharksystem/asap/engine/ASAPInternalPeer.java

@@ -6,6 +6,7 @@
 import net.sharksystem.asap.protocol.*;
 import net.sharksystem.asap.crypto.ASAPKeyStore;
 
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Set;
@@ -113,4 +114,18 @@ void sendOnlineASAPAssimilateMessage(CharSequence format, CharSequence urlTarget
     ASAPKeyStore getASAPKeyStore() throws ASAPSecurityException;
 
     void setSecurityAdministrator(DefaultSecurityAdministrator securityAdministrator);
+
+    /**
+     * Make a value persistent with key
+     * @param key
+     * @param value
+     */
+    void putExtra(CharSequence key, byte[] value) throws IOException, ASAPException;
+
+    /**
+     * Return a value. Throws an exception if not set
+     * @param key
+     * @throws ASAPException key never used in putExtra
+     */
+    byte[] getExtra(CharSequence key) throws ASAPException, IOException;
 }

src/net/sharksystem/asap/engine/ASAPInternalPeerFS.java

@@ -2,6 +2,7 @@
 
 import net.sharksystem.asap.EncounterConnectionType;
 import net.sharksystem.asap.crypto.*;
+import net.sharksystem.asap.utils.ASAPSerialization;
 import net.sharksystem.utils.Utils;
 import net.sharksystem.asap.ASAP;
 import net.sharksystem.asap.ASAPException;
@@ -91,7 +92,7 @@ private ASAPInternalPeerFS(CharSequence owner, CharSequence rootFolderName, long
         // owner id must not be a numerical value only - it would interfere with our era numbers
         try {
             Integer.parseInt(owner.toString());
-            throw new ASAPException("peer id must not only a numeric number, like 42. " +
+            throw new ASAPException("peer id must not only be a numeric number like 42. " +
                     "It can be ArthurDent_42, though: " + owner);
         }
         catch(NumberFormatException e) {
@@ -155,6 +156,8 @@ private ASAPInternalPeerFS(CharSequence owner, CharSequence rootFolderName, long
             }
         }
 
+        this.restoreExtraData();
+
 //        System.out.println(this.getLogStart() + "SHOULD also set up engine " + FORMAT_UNDECRYPTABLE_MESSAGES);
     }
 
@@ -678,4 +681,127 @@ public ASAPKeyStore getASAPKeyStore() throws ASAPSecurityException {
         }
         return this.inMemoASAPKeyStore;
     }
+
+    ///////////////////////////////////////////////////////////////////////////////////////////////////////////
+    //                                        make extra data persist                                        //
+    ///////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+    public static final String EXTRA_FILE_NAME = ".extraData";
+    private Map<CharSequence, byte[]> extraData = new HashMap<>();
+
+    private File getExtraFile() {
+        String extraFileName = this.rootFolderName + "/" + EXTRA_FILE_NAME;
+        return new File(extraFileName);
+    }
+
+    /*
+    Here is the catch... There can be - and in Android will - two instances share data over file system. The use
+    same clock but run in different threads, most likely different processes. We have to synchronize both sides.
+
+    There will be two processes A and B. Let's assume we are in process A.
+    a) We never written something,
+
+     */
+
+    private long timeStampSyncExtraData = -1; // never saved anything
+
+    private void extraDataSync() throws IOException, ASAPException {
+        InputStream is = null;
+        try {
+            is = new FileInputStream(this.getExtraFile());
+        }
+        catch(IOException ioEx) {
+            // no such file - save it instead - there is no conflict
+            this.saveExtraData();
+            return;
+        }
+
+        // read time stamp
+        long timeStampSaved = ASAPSerialization.readLongParameter(is);
+
+        if(this.timeStampSyncExtraData < timeStampSaved) {
+            // there is an external copy that was created after our last sync
+        }
+
+        // discard local changes and read from file
+        this.restoreExtraData();
+    }
+
+    public void saveExtraData() throws IOException {
+        OutputStream os = new FileOutputStream(this.getExtraFile());
+
+        // write time stamp
+        this.timeStampSyncExtraData = System.currentTimeMillis();
+        ASAPSerialization.writeLongParameter(this.timeStampSyncExtraData, os);
+        ASAPSerialization.writeNonNegativeIntegerParameter(this.extraData.size(), os);
+
+        for(CharSequence key : this.extraData.keySet()) {
+            // write key
+            ASAPSerialization.writeCharSequenceParameter(key, os);
+            // value
+            ASAPSerialization.writeByteArray(this.extraData.get(key), os);
+        }
+
+        os.close();
+    }
+
+    /**
+     * Always restore. If there is no such file - write it.
+     * @throws IOException
+     * @throws ASAPException
+     */
+    public void restoreExtraData() throws IOException, ASAPException {
+        InputStream is = null;
+        try {
+             is = new FileInputStream(this.getExtraFile());
+        }
+        catch(IOException ioEx) {
+            // no such file - nothing to do here
+            return;
+        }
+
+        long timeStampSaved = ASAPSerialization.readLongParameter(is);
+        if(timeStampSaved == this.timeStampSyncExtraData) {
+            is.close();
+            return;
+        }
+
+        // something changed - get a fresh copy
+        this.timeStampSyncExtraData = timeStampSaved;
+
+        this.extraData = new HashMap<>();
+        int counter = ASAPSerialization.readIntegerParameter(is);
+
+        while(counter-- > 0) {
+            // read key
+            CharSequence key = ASAPSerialization.readCharSequenceParameter(is);
+            // value
+            byte[] value = ASAPSerialization.readByteArray(is);
+
+            // save in memory
+            this.extraData.put(key, value);
+        }
+        is.close();
+    }
+
+    /**
+     * Make a value persistent with key
+     * @param key
+     * @param value
+     */
+    public void putExtra(CharSequence key, byte[] value) throws IOException, ASAPException {
+        this.extraDataSync();
+        this.extraData.put(key, value);
+        this.saveExtraData();
+    }
+
+    /**
+     * Return a value - can be null if null was set as value.
+     * @param key
+     * @throws ASAPException key never used in putExtra
+     */
+    public byte[] getExtra(CharSequence key) throws IOException, ASAPException {
+        this.restoreExtraData();
+        return this.extraData.get(key);
+    }
 }

src/net/sharksystem/asap/utils/ASAPSerialization.java

@@ -21,15 +21,20 @@ public class ASAPSerialization {
     public static final short BLANK_RIGHT_SHORT = (short) 0xFF00;
 
     public static void writeByteArray(byte[] bytes2Write, OutputStream os) throws IOException {
-        writeNonNegativeIntegerParameter(bytes2Write.length, os);
-        os.write(bytes2Write);
+        if(bytes2Write == null) {
+            writeNonNegativeIntegerParameter(0, os);
+        } else {
+            writeNonNegativeIntegerParameter(bytes2Write.length, os);
+            os.write(bytes2Write);
+        }
     }
 
     public static byte[] readByteArray(InputStream is) throws IOException, ASAPException {
         // read len
         int len = readIntegerParameter(is);
-        byte[] messageBytes = new byte[len];
+        if(len == 0) return new byte[0];
 
+        byte[] messageBytes = new byte[len];
         // read encrypted bytes from stream
         is.read(messageBytes);
 

src/net/sharksystem/asap/utils/Helper.java

@@ -146,4 +146,16 @@ public static ASAPMessages getMessagesByChunkReceivedInfos(String format, String
 
         return null;
     }
+
+    public static final boolean sameByteArray(byte[] a, byte[] b) {
+        if(a == null && b == null) return true;
+        if(a.length != b.length) return false;
+
+        // not null, same length
+        for(int i = 0; i < a.length; i++) {
+            if(a[i] != b[i]) return false;
+        }
+
+        return true;
+    }
 }

test/net/sharksystem/asap/engine/UsageExamples.java

@@ -132,4 +132,33 @@ public void basicTwoPartyTest() throws IOException, ASAPException, InterruptedEx
             System.out.println("message received: " + msg);
         }
     }
+
+    @Test
+    public void workWithExtraData() throws IOException, ASAPException, InterruptedException {
+        ASAPEngineFS.removeFolder(WORKING_SUB_DIRECTORY); // clean previous version before
+
+        ///// Prepare Alice
+        String aliceFolder = WORKING_SUB_DIRECTORY + ALICE_PEER_NAME;
+
+        // setup alice peer
+        ASAPInternalPeer alicePeer = ASAPInternalPeerFS.createASAPPeer(ALICE_PEER_NAME, aliceFolder, null);
+
+        String key1 = "testKey";
+        byte[] value1 = "TestString".getBytes();
+
+        String key2 = "testKey2";
+        byte[] value2 = "TestString2".getBytes();
+
+        alicePeer.putExtra(key1, value1);
+        alicePeer.putExtra(key2, value2);
+
+        // set up new peer object
+        ASAPInternalPeer alicePeer2 = ASAPInternalPeerFS.createASAPPeer(ALICE_PEER_NAME, aliceFolder, null);
+
+        byte[] valueR1 = alicePeer2.getExtra(key1);
+        Assert.assertTrue(Helper.sameByteArray(value1, valueR1));
+
+        byte[] valueR2 = alicePeer2.getExtra(key2);
+        Assert.assertTrue(Helper.sameByteArray(value2, valueR2));
+    }
 }