Read gzip/zip file.

app/src/main/java/org/gnucash/android/app/GnuCashApplication.java

@@ -455,6 +455,18 @@ public static boolean shouldBackupTransactions(Context context) {
         return sharedPrefs.getBoolean(context.getString(R.string.key_delete_transaction_backup), true);
     }
 
+    /**
+     * Returns <code>true</code> if setting is enabled to backup the book before importing a book,
+     * <code>false</code> otherwise.
+     *
+     * @param context The context.
+     * @return <code>true</code> if the book should be backed-up.
+     */
+    public static boolean shouldBackupForImport(Context context) {
+        SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(context);
+        return sharedPrefs.getBoolean(context.getString(R.string.key_import_book_backup), true);
+    }
+
     /**
      * Get the default transaction type.
      *

app/src/main/java/org/gnucash/android/importer/GncXmlImporter.java

@@ -16,6 +16,10 @@
  */
 package org.gnucash.android.importer;
 
+import static java.util.zip.GZIPInputStream.GZIP_MAGIC;
+
+import androidx.annotation.NonNull;
+
 import org.gnucash.android.db.adapter.TransactionsDbAdapter;
 import org.gnucash.android.model.Book;
 import org.gnucash.android.util.PreferencesHelper;
@@ -24,10 +28,12 @@
 import org.xml.sax.XMLReader;
 
 import java.io.BufferedInputStream;
+import java.io.EOFException;
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.PushbackInputStream;
 import java.util.zip.GZIPInputStream;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipInputStream;
 
 import javax.xml.parsers.ParserConfigurationException;
 import javax.xml.parsers.SAXParser;
@@ -42,6 +48,10 @@
  */
 public class GncXmlImporter {
 
+    private static final int ZIP_MAGIC = 0x504B0304;
+    private static final int ZIP_MAGIC_EMPTY = 0x504B0506;
+    private static final int ZIP_MAGIC_SPANNED = 0x504B0708;
+
     /**
      * Parse GnuCash XML input and populates the database
      *
@@ -58,37 +68,65 @@ public static String parse(InputStream gncXmlInputStream) throws ParserConfigura
      * @param gncXmlInputStream InputStream source of the GnuCash XML file
      * @return the book into which the XML was imported
      */
-    public static Book parseBook(InputStream gncXmlInputStream) throws ParserConfigurationException, SAXException, IOException {
-        SAXParserFactory spf = SAXParserFactory.newInstance();
-        SAXParser sp = spf.newSAXParser();
-        XMLReader xr = sp.getXMLReader();
-
-        BufferedInputStream bos;
-        PushbackInputStream pb = new PushbackInputStream(gncXmlInputStream, 2); //we need a pushbackstream to look ahead
-        byte[] signature = new byte[2];
-        pb.read(signature); //read the signature
-        pb.unread(signature); //push back the signature to the stream
-        if (signature[0] == (byte) 0x1f && signature[1] == (byte) 0x8b) //check if matches standard gzip magic number
-            bos = new BufferedInputStream(new GZIPInputStream(pb));
-        else
-            bos = new BufferedInputStream(pb);
-
+    public static Book parseBook(@NonNull InputStream gncXmlInputStream) throws ParserConfigurationException, SAXException, IOException {
         //TODO: Set an error handler which can log errors
         Timber.d("Start import");
+        InputStream input = getInputStream(gncXmlInputStream);
         GncXmlHandler handler = new GncXmlHandler();
-        xr.setContentHandler(handler);
+        XMLReader reader = createXMLReader(handler);
+
         long startTime = System.nanoTime();
-        xr.parse(new InputSource(bos));
+        reader.parse(new InputSource(input));
         long endTime = System.nanoTime();
         Timber.d("%d ns spent on importing the file", endTime - startTime);
 
         Book book = handler.getImportedBook();
         String bookUID = book.getUID();
         PreferencesHelper.setLastExportTime(
-                TransactionsDbAdapter.getInstance().getTimestampOfLastModification(),
-                bookUID
+            TransactionsDbAdapter.getInstance().getTimestampOfLastModification(),
+            bookUID
         );
 
         return book;
     }
+
+    @NonNull
+    private static InputStream getInputStream(InputStream inputStream) throws IOException {
+        BufferedInputStream bis = new BufferedInputStream(inputStream);
+        bis.mark(4);
+        int byte0 = bis.read();
+        if (byte0 == -1) throw new EOFException("file too small");
+        int byte1 = bis.read();
+        if (byte1 == -1) throw new EOFException("file too small");
+        int byte2 = bis.read();
+        if (byte2 == -1) throw new EOFException("file too small");
+        int byte3 = bis.read();
+        if (byte3 == -1) throw new EOFException("file too small");
+        bis.reset(); //push back the signature to the stream
+
+        int signature2 = ((byte1 & 0xFF) << 8) | (byte0 & 0xFF);
+        //check if matches standard gzip magic number
+        if (signature2 == GZIP_MAGIC) {
+            return new GZIPInputStream(bis);
+        }
+
+        int signature4 = ((byte3 & 0xFF) << 24) | ((byte2 & 0xFF) << 16) | signature2;
+        if ((signature4 == ZIP_MAGIC) || (signature4 == ZIP_MAGIC_EMPTY) || (signature4 == ZIP_MAGIC_SPANNED)) {
+            ZipInputStream zis = new ZipInputStream(bis);
+            ZipEntry entry = zis.getNextEntry();
+            if (entry != null) {
+                return zis;
+            }
+        }
+
+        return bis;
+    }
+
+    private static XMLReader createXMLReader(GncXmlHandler handler) throws ParserConfigurationException, SAXException {
+        SAXParserFactory spf = SAXParserFactory.newInstance();
+        SAXParser sp = spf.newSAXParser();
+        XMLReader xr = sp.getXMLReader();
+        xr.setContentHandler(handler);
+        return xr;
+    }
 }

app/src/main/java/org/gnucash/android/importer/ImportAsyncTask.java

@@ -81,12 +81,15 @@ protected String doInBackground(Uri... uris) {
         if (mBackup) {
             BackupManager.backupActiveBook();
         }
+        if (isCancelled()) {
+            return null;
+        }
 
         Uri uri = uris[0];
-        ContentResolver contentResolver = mContext.getContentResolver();
         Book book;
         String bookUID;
         try {
+            ContentResolver contentResolver = mContext.getContentResolver();
             InputStream accountInputStream = contentResolver.openInputStream(uri);
             book = GncXmlImporter.parseBook(accountInputStream);
             book.setSourceUri(uri);

app/src/main/java/org/gnucash/android/ui/account/AccountsActivity.java

@@ -498,7 +498,8 @@ public static void startXmlFileChooser(Fragment fragment) {
      * @param onFinishTask Task to be executed when import is complete
      */
     public static void importXmlFileFromIntent(Activity context, Intent data, TaskDelegate onFinishTask) {
-        new ImportAsyncTask(context, onFinishTask, true).execute(data.getData());
+        boolean backup = GnuCashApplication.shouldBackupForImport(context);
+        new ImportAsyncTask(context, onFinishTask, backup).execute(data.getData());
     }
 
     /**

app/src/main/res/values/donottranslate.xml

@@ -38,6 +38,7 @@
     <string name="key_backup_location" translatable="false">backup_location</string>
     <string name="key_export_accounts_csv" translatable="false">export_accounts_csv_key</string>
     <string name="key_delete_transaction_backup" translatable="false">delete_transaction_backup</string>
+    <string name="key_import_book_backup" translatable="false">import_book_backup</string>
     <!-- This is the filename for default backups. So use only simple characters and no spaces. Do not change the extension -->
     <string name="label_backup_filename" translatable="false">gnucash_pocket_backup.gnca</string>
     <string-array name="key_account_type_entries" translatable="false">

app/src/main/res/values/strings.xml

@@ -248,8 +248,10 @@
     <string name="title_dropbox_sync_preference">Enable DropBox</string>
     <string name="title_owncloud_sync_preference">Enable ownCloud </string>
     <string name="title_backup_preference_category">Backup</string>
-    <string name="title_delete_transaction_backup">When delete transaction?</string>
-    <string name="summary_delete_transaction_backup">Backup active book when delete a transaction?</string>
+    <string name="title_delete_transaction_backup">When deleting a transaction?</string>
+    <string name="summary_delete_transaction_backup">Backup the active book before deleting a transaction?</string>
+    <string name="title_import_book_backup">When importing a book?</string>
+    <string name="summary_import_book_backup">Backup the active book before importing a book?</string>
     <string name="summary_dropbox_sync">Enable exporting to DropBox</string>
     <string name="summary_owncloud_sync">Enable exporting to ownCloud</string>
     <string name="title_backup_prefs">Backup Preferences</string>

app/src/main/res/xml/fragment_backup_preferences.xml

@@ -50,6 +50,12 @@
             android:key="@string/key_delete_transaction_backup"
             android:summary="@string/summary_delete_transaction_backup"
             android:title="@string/title_delete_transaction_backup" />
+
+        <androidx.preference.SwitchPreference
+            android:defaultValue="true"
+            android:key="@string/key_import_book_backup"
+            android:summary="@string/summary_import_book_backup"
+            android:title="@string/title_import_book_backup" />
     </androidx.preference.PreferenceCategory>
     <androidx.preference.PreferenceCategory android:title="@string/title_export_preference_category">