[android] Added downloader with resume support

android/src/com/mapswithme/maps/downloader/DownloadFilesTask.java

@@ -0,0 +1,103 @@
+package com.mapswithme.maps.downloader;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.HttpURLConnection;
+import java.util.HashSet;
+
+import android.os.AsyncTask;
+
+// Checks if incomplete file exists and resumes it's download
+// Downloads from scratch otherwise
+class DownloadFilesTask extends AsyncTask<Void, Long, IDownloadObserver.DownloadResult>
+{
+  public final HttpParams m_params;
+  // Stored here to remove finished tasks 
+  private final HashSet<DownloadFilesTask> m_activeTasks;
+
+  DownloadFilesTask(final HttpParams params, HashSet<DownloadFilesTask> activeTasks)
+  {
+    m_params = params;
+    m_activeTasks = activeTasks;
+  }
+
+  @Override
+  protected void onPreExecute()
+  {
+  }
+
+  @Override
+  protected void onPostExecute(IDownloadObserver.DownloadResult result)
+  {
+    m_activeTasks.remove(this);
+    m_params.m_observer.OnFinish(m_params, result);
+  }
+  
+  @Override
+  protected void onCancelled()
+  {
+
+  }
+
+  @Override
+  protected void onProgressUpdate(Long... progress)
+  {
+    m_params.m_observer.OnProgress(m_params, progress[0], progress[1]);
+  }
+  
+  @Override
+  protected IDownloadObserver.DownloadResult doInBackground(Void... p)
+  {
+    IDownloadObserver.DownloadResult retCode = IDownloadObserver.DownloadResult.EFailed;
+    try
+    {
+      retCode = downloadUrl(m_params);
+    } catch (IOException e)
+    {
+    }
+    return retCode;
+  }
+
+  private IDownloadObserver.DownloadResult downloadUrl(HttpParams param) throws IOException
+  {
+    final File file = new File(new StringBuilder(m_params.m_fileToSave).append(
+        ".downloading").toString());
+    final FileOutputStream os = new FileOutputStream(file, true);
+
+    HttpURLConnection urlConnection = (HttpURLConnection) param.m_url
+        .openConnection();
+    final long resumeFileLen = file.length();
+    if (resumeFileLen > 0)
+      urlConnection.setRequestProperty("Range", new StringBuilder("bytes=%1-")
+          .append(resumeFileLen).toString());
+
+    try
+    {
+      final InputStream is = urlConnection.getInputStream();
+      if (!param.m_url.getHost().equals(urlConnection.getURL().getHost()))
+      {
+        return IDownloadObserver.DownloadResult.ERedirected;
+      }
+      else
+      {
+        byte[] buffer = new byte[1024];
+        int len;
+        final long totalLen = urlConnection.getContentLength();
+        long sum = 0;
+        while ((len = is.read(buffer)) >= 0 && !isCancelled())
+        {
+          os.write(buffer, 0, len);
+          sum += len;
+          publishProgress(sum, totalLen);
+        }
+      }
+    }
+    finally
+    {
+      urlConnection.disconnect();
+    }
+    return IDownloadObserver.DownloadResult.EOk;
+  }
+}

android/src/com/mapswithme/maps/downloader/DownloadManager.java

@@ -0,0 +1,56 @@
+package com.mapswithme.maps.downloader;
+
+import java.net.URL;
+import java.util.HashSet;
+import java.util.Iterator;
+
+import android.util.Log;
+
+import com.mapswithme.maps.downloader.DownloadFilesTask;
+import com.mapswithme.maps.downloader.HttpParams;
+
+public class DownloadManager
+{
+  private static final String TAG = "DownloadManager";
+  
+  private static HashSet<DownloadFilesTask> m_activeTasks = new HashSet<DownloadFilesTask>(); 
+  
+  public static void httpGet(URL url, String fileToSave, IDownloadObserver observer)
+  {
+    Iterator<DownloadFilesTask> iterator = m_activeTasks.iterator();
+    while (iterator.hasNext())
+    {
+      if (iterator.next().m_params.m_url == url)
+      {
+        Log.w(TAG, "File is already downloading: " + url.toString());
+        return;
+      }
+    }
+    final DownloadFilesTask task = new DownloadFilesTask(new HttpParams(url, fileToSave, observer), m_activeTasks);
+    m_activeTasks.add(task);
+    task.execute();
+  }
+
+  public static void cancelDownload(URL url)
+  {
+    Iterator<DownloadFilesTask> iterator = m_activeTasks.iterator();
+    while (iterator.hasNext())
+    {
+      final DownloadFilesTask task = iterator.next();
+      if (task.m_params.m_url == url)
+      {
+        task.cancel(false);
+        iterator.remove();
+        break;
+      }
+    }
+  }
+  
+  public static void cancelAllDownloads()
+  {
+    Iterator<DownloadFilesTask> iterator = m_activeTasks.iterator();
+    while (iterator.hasNext())
+      iterator.next().cancel(false);
+    m_activeTasks.clear();
+  }
+}

android/src/com/mapswithme/maps/downloader/HttpParams.java

@@ -0,0 +1,17 @@
+package com.mapswithme.maps.downloader;
+
+import java.net.URL;
+
+public class HttpParams
+{
+  public final URL m_url;
+  public final String m_fileToSave;
+  public final IDownloadObserver m_observer;
+  
+  public HttpParams(URL url, String fileToSave, IDownloadObserver observer)
+  {
+    m_url = url;
+    m_fileToSave = fileToSave;
+    m_observer = observer;
+  }
+}

android/src/com/mapswithme/maps/downloader/IDownloadObserver.java

@@ -0,0 +1,14 @@
+package com.mapswithme.maps.downloader;
+
+public interface IDownloadObserver
+{
+  public enum DownloadResult
+  {
+    EOk,
+    EFailed,
+    ERedirected
+  }
+  
+  public abstract void OnFinish(final HttpParams params, final DownloadResult result);
+  public abstract void OnProgress(final HttpParams params, final Long current, final Long total);
+}