nani/app

Julien LepillerSun May 31 17:04:20+0200 2020

9580110

Remove partial download of different versions of the file

CHANGELOG.md

 * When a file is already downloaded, updating it will append to it instead
   of overriding it.
 * When a file is partially downloaded but updated on server, remove the old
   partial file as continuing download would cause a hash mismatch.
 Changes In 0.2.1
 -----------------

app/src/main/java/eu/lepiller/nani/DictionaryDownloadActivity.java

                         input = connection.getInputStream();
                         file = new File(e.getValue() + ".sha256");
                         file.getParentFile().mkdirs();
                         File old_file = new File(file + ".old");
                         if(old_file.exists()) {
                             old_file.delete();
                         }
                         if(file.exists()) {
                             file.renameTo(old_file);
                         }
                         output = new FileOutputStream(file);
                         while((count = input.read(data)) != -1) {
                             if (isCancelled()) {
                             }
                             output.write(data, 0, count);
                         }
                         if(old_file.exists()) {
                             // Check that we continue to download the same file
                             String old_hash = Dictionary.readSha256FromFile(old_file);
                             String new_hash = Dictionary.readSha256FromFile(file);
                             if(old_hash.compareTo(new_hash) != 0) {
                                 // Remove file that is now different
                                 d.remove();
                             }
                             old_file.delete();
                         }
                     }
                     // .sha256 file now downloaded

app/src/main/java/eu/lepiller/nani/dictionary/Dictionary.java

 import android.content.Context;
 import android.graphics.drawable.Drawable;
 import android.os.Build;
 import android.util.Log;
 import androidx.vectordrawable.graphics.drawable.VectorDrawableCompat;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.FileReader;
 import java.io.IOException;
 import java.net.URL;
 import java.util.Map;
     abstract int getDrawableId();
     abstract public void remove();
     public static String readSha256FromFile(File file) throws IOException {
         StringBuilder sb = new StringBuilder();
         char data[] = new char[4096];
         FileReader fr = new FileReader(file);
         int count;
         while((count = fr.read(data)) != -1) {
             sb.append(data, 0, count);
         }
         return sb.toString().trim();
     }
 }

app/src/main/java/eu/lepiller/nani/dictionary/FileDictionary.java

                 byte[] result = digest.digest();
                 String hash = String.format("%0" + (result.length*2) + "X", new BigInteger(1, result)).toLowerCase();
                 StringBuilder sb = new StringBuilder();
                 try {
                     char data[] = new char[4096];
                     FileReader fr = new FileReader(sha256);
                     int count;
                     while((count = fr.read(data)) != -1) {
                         sb.append(data, 0, count);
                     }
                     String expected = readSha256FromFile(sha256);
                     // If the file has the expected hash, we have it
                     Log.d(TAG, "expected: " + sb.toString().trim() + "; actual: " + hash);
                     return sb.toString().trim().compareTo(hash) == 0;
                     Log.d(TAG, "expected: " + expected + "; actual: " + hash);
                     return expected.compareTo(hash) == 0;
                 } catch (FileNotFoundException e) {
                     e.printStackTrace();
                 } catch (IOException e) {