Split net.Downloader into abstract Downloader and concrete HttpDownloader.

This will allow the more general, non HTTP related stuff (progress events,
stream copying) to occur in a separate base class. HTTP specific stuff
(HTTP status codes, etag cache checking) is done in the HTTPDownloader
base class.

src/org/fdroid/fdroid/net/Downloader.java

@@ -5,24 +5,18 @@ import java.net.*;
 import android.content.*;
 import org.fdroid.fdroid.*;
 
-public class Downloader {
+public abstract class Downloader {
 
-    private static final String HEADER_IF_NONE_MATCH = "If-None-Match";
-    private static final String HEADER_FIELD_ETAG = "ETag";
-
-    private URL sourceUrl;
     private OutputStream outputStream;
     private ProgressListener progressListener = null;
     private ProgressListener.Event progressEvent = null;
-    private String eTag = null;
     private final File outputFile;
-    private HttpURLConnection connection;
+
-    private int statusCode = -1;
+    public abstract InputStream inputStream() throws IOException;
 
     // The context is required for opening the file to write to.
-    public Downloader(String source, String destFile, Context ctx)
+    public Downloader(String destFile, Context ctx)
             throws FileNotFoundException, MalformedURLException {
-        sourceUrl    = new URL(source);
         outputStream = ctx.openFileOutput(destFile, Context.MODE_PRIVATE);
         outputFile   = new File(ctx.getFilesDir() + File.separator + destFile);
     }
@@ -32,16 +26,14 @@ public class Downloader {
      * you are done*.
      * @see org.fdroid.fdroid.net.Downloader#getFile()
      */
-    public Downloader(String source, Context ctx) throws IOException {
+    public Downloader(Context ctx) throws IOException {
         // http://developer.android.com/guide/topics/data/data-storage.html#InternalCache
         outputFile = File.createTempFile("dl-", "", ctx.getCacheDir());
         outputStream = new FileOutputStream(outputFile);
-        sourceUrl = new URL(source);
     }
 
-    public Downloader(String source, OutputStream output)
+    public Downloader(OutputStream output)
             throws MalformedURLException {
-        sourceUrl    = new URL(source);
         outputStream = output;
         outputFile   = null;
     }
@@ -61,82 +53,25 @@ public class Downloader {
         return outputFile;
     }
 
-    /**
+    private void setupProgressListener() {
-     * Only available after downloading a file.
+        if (progressListener != null && progressEvent != null) {
-     */
+            progressEvent.total = totalDownloadSize();
-    public int getStatusCode() {
+        }
-        return statusCode;
     }
 
-    /**
+    protected abstract int totalDownloadSize();
-     * If you ask for the eTag before calling download(), you will get the
-     * same one you passed in (if any). If you call it after download(), you
-     * will get the new eTag from the server, or null if there was none.
-     */
-    public String getETag() {
-        return eTag;
-    }
 
-    /**
+    public void download() throws IOException {
-     * If this eTag matches that returned by the server, then no download will
-     * take place, and a status code of 304 will be returned by download().
-     */
-    public void setETag(String eTag) {
-        this.eTag = eTag;
-    }
-
-    // Get a remote file. Returns the HTTP response code.
-    // If 'etag' is not null, it's passed to the server as an If-None-Match
-    // header, in which case expect a 304 response if nothing changed.
-    // In the event of a 200 response ONLY, 'retag' (which should be passed
-    // empty) may contain an etag value for the response, or it may be left
-    // empty if none was available.
-    public int download() throws IOException {
-        connection = (HttpURLConnection)sourceUrl.openConnection();
-        setupCacheCheck();
-        statusCode = connection.getResponseCode();
-        if (statusCode == 200) {
         setupProgressListener();
         InputStream input = null;
         try {
-                input = connection.getInputStream();
+            input = inputStream();
             Utils.copy(input, outputStream,
                     progressListener, progressEvent);
         } finally {
             Utils.closeQuietly(outputStream);
             Utils.closeQuietly(input);
         }
-            updateCacheCheck();
-        }
-        return statusCode;
-    }
-
-    protected void setupCacheCheck() {
-        if (eTag != null) {
-            connection.setRequestProperty(HEADER_IF_NONE_MATCH, eTag);
-        }
-    }
-
-    protected void updateCacheCheck() {
-        eTag = connection.getHeaderField(HEADER_FIELD_ETAG);
-    }
-
-    protected void setupProgressListener() {
-        if (progressListener != null && progressEvent != null) {
-            // Testing in the emulator for me, showed that figuring out the
-            // filesize took about 1 to 1.5 seconds.
-            // To put this in context, downloading a repo of:
-            //  - 400k takes ~6 seconds
-            //  - 5k   takes ~3 seconds
-            // on my connection. I think the 1/1.5 seconds is worth it,
-            // because as the repo grows, the tradeoff will
-            // become more worth it.
-            progressEvent.total = connection.getContentLength();
-        }
-    }
-
-    public boolean hasChanged() {
-        return this.statusCode == 200;
     }
 
 }

src/org/fdroid/fdroid/net/HttpDownloader.java

@@ -0,0 +1,115 @@
+package org.fdroid.fdroid.net;
+
+import android.content.Context;
+
+import java.io.*;
+import java.net.HttpURLConnection;
+import java.net.MalformedURLException;
+import java.net.URL;
+
+public class HttpDownloader extends Downloader {
+
+    private static final String HEADER_IF_NONE_MATCH = "If-None-Match";
+    private static final String HEADER_FIELD_ETAG = "ETag";
+
+    private URL sourceUrl;
+    private String eTag = null;
+    private HttpURLConnection connection;
+    private int statusCode = -1;
+
+    // The context is required for opening the file to write to.
+    public HttpDownloader(String source, String destFile, Context ctx)
+            throws FileNotFoundException, MalformedURLException {
+        super(destFile, ctx);
+        sourceUrl = new URL(source);
+    }
+
+    /**
+     * Downloads to a temporary file, which *you must delete yourself when
+     * you are done*.
+     * @see org.fdroid.fdroid.net.HttpDownloader#getFile()
+     */
+    public HttpDownloader(String source, Context ctx) throws IOException {
+        super(ctx);
+        sourceUrl = new URL(source);
+    }
+
+    public HttpDownloader(String source, OutputStream output)
+            throws MalformedURLException {
+        super(output);
+        sourceUrl = new URL(source);
+    }
+
+    public InputStream inputStream() throws IOException {
+        return connection.getInputStream();
+    }
+
+    // Get a remote file. Returns the HTTP response code.
+    // If 'etag' is not null, it's passed to the server as an If-None-Match
+    // header, in which case expect a 304 response if nothing changed.
+    // In the event of a 200 response ONLY, 'retag' (which should be passed
+    // empty) may contain an etag value for the response, or it may be left
+    // empty if none was available.
+    public int downloadHttpFile() throws IOException {
+        connection = (HttpURLConnection)sourceUrl.openConnection();
+        setupCacheCheck();
+        statusCode = connection.getResponseCode();
+        if (statusCode == 200) {
+            download();
+            updateCacheCheck();
+        }
+        return statusCode;
+    }
+
+    /**
+     * Only available after downloading a file.
+     */
+    public int getStatusCode() {
+        return statusCode;
+    }
+
+    /**
+     * If you ask for the eTag before calling download(), you will get the
+     * same one you passed in (if any). If you call it after download(), you
+     * will get the new eTag from the server, or null if there was none.
+     */
+    public String getETag() {
+        return eTag;
+    }
+
+    /**
+     * If this eTag matches that returned by the server, then no download will
+     * take place, and a status code of 304 will be returned by download().
+     */
+    public void setETag(String eTag) {
+        this.eTag = eTag;
+    }
+
+
+    protected void setupCacheCheck() {
+        if (eTag != null) {
+            connection.setRequestProperty(HEADER_IF_NONE_MATCH, eTag);
+        }
+    }
+
+    protected void updateCacheCheck() {
+        eTag = connection.getHeaderField(HEADER_FIELD_ETAG);
+    }
+
+    // Testing in the emulator for me, showed that figuring out the
+    // filesize took about 1 to 1.5 seconds.
+    // To put this in context, downloading a repo of:
+    //  - 400k takes ~6 seconds
+    //  - 5k   takes ~3 seconds
+    // on my connection. I think the 1/1.5 seconds is worth it,
+    // because as the repo grows, the tradeoff will
+    // become more worth it.
+    protected int totalDownloadSize() {
+        return connection.getContentLength();
+    }
+
+    public boolean hasChanged() {
+        return this.statusCode == 200;
+    }
+
+}

src/org/fdroid/fdroid/updater/RepoUpdater.java

@@ -12,6 +12,7 @@ import org.fdroid.fdroid.data.App;
 import org.fdroid.fdroid.data.Repo;
 import org.fdroid.fdroid.data.RepoProvider;
 import org.fdroid.fdroid.net.Downloader;
+import org.fdroid.fdroid.net.HttpDownloader;
 import org.xml.sax.InputSource;
 import org.xml.sax.SAXException;
 import org.xml.sax.XMLReader;
@@ -84,11 +85,11 @@ abstract public class RepoUpdater {
 
     protected abstract String getIndexAddress();
 
-    protected Downloader downloadIndex() throws UpdateException {
+    protected HttpDownloader downloadIndex() throws UpdateException {
         Bundle progressData = createProgressData(repo.address);
-        Downloader downloader = null;
+        HttpDownloader downloader = null;
         try {
-            downloader = new Downloader(getIndexAddress(), context);
+            downloader = new HttpDownloader(getIndexAddress(), context);
             downloader.setETag(repo.lastetag);
 
             if (isInteractive()) {
@@ -98,7 +99,7 @@ abstract public class RepoUpdater {
                 downloader.setProgressListener(progressListener, event);
             }
 
-            int status = downloader.download();
+            int status = downloader.downloadHttpFile();
 
             if (status == 304) {
                 // The index is unchanged since we last read it. We just mark
@@ -169,7 +170,7 @@ abstract public class RepoUpdater {
         File indexFile = null;
         try {
 
-            Downloader downloader = downloadIndex();
+            HttpDownloader downloader = downloadIndex();
             hasChanged = downloader.hasChanged();
 
             if (hasChanged) {