Reorganise database access to prevent locking issues

src/org/fdroid/fdroid/AppDetails.java

@@ -23,6 +23,8 @@ import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.fdroid.fdroid.DB.Apk.CompatibilityChecker;
+
 import android.app.AlertDialog;
 import android.app.ListActivity;
 import android.app.ProgressDialog;
@@ -157,13 +159,12 @@ public class AppDetails extends ListActivity {
     private static final int MARKET = Menu.FIRST + 5;
     private static final int DONATE = Menu.FIRST + 6;
 
-    private DB db;
     private DB.App app;
     private int app_currentvercode;
     private DB.Apk curapk;
     private String appid;
+    private CompatibilityChecker compatChecker;
     private PackageManager mPm;
-    private DB.Apk.CompatibilityChecker compatChecker;
     private DownloadHandler downloadHandler;
     private boolean stateRetained;
 
@@ -197,8 +198,6 @@ public class AppDetails extends ListActivity {
     @Override
     protected void onStart() {
         super.onStart();
-        db = new DB(this);
-        compatChecker = db.getCompatibilityChecker();
         mPm = getPackageManager();
         // Get the preferences we're going to use in this Activity...
         SharedPreferences prefs = PreferenceManager
@@ -235,8 +234,6 @@ public class AppDetails extends ListActivity {
 
     @Override
     protected void onStop() {
-        db.close();
-        db = null;
         super.onStop();
     }
 
@@ -275,8 +272,15 @@ public class AppDetails extends ListActivity {
     // also when something has been installed/uninstalled.
     private void reset() {
         Log.d("FDroid", "Getting application details for " + appid);
+        DB.Apk curver;
+        try {
+            DB db = DB.getDB();
+            compatChecker = db.getCompatibilityChecker();
             app = db.getApps(appid, null, true, false).get(0);
-        DB.Apk curver = app.getCurrentVersion(compatChecker);
+            curver = app.getCurrentVersion(compatChecker);
+        } finally {
+            DB.releaseDB();
+        }
         app_currentvercode = curver == null ? 0 : curver.vercode;
 
         // Get the signature of the installed package...

src/org/fdroid/fdroid/DB.java

@@ -27,6 +27,7 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Vector;
+import java.util.concurrent.Semaphore;
 
 import android.content.ContentValues;
 import android.content.Context;
@@ -44,6 +45,31 @@ import android.util.Log;
 
 public class DB {
 
+    private static Semaphore dbSync = new Semaphore(1, true);
+    static DB dbInstance = null;
+
+    // Initialise the database. Called once when the application starts up.
+    static void initDB(Context ctx) {
+        dbInstance = new DB(ctx);
+    }
+    
+    // Get access to the database. Must be called before any database activity,
+    // and releaseDB must be called subsequently. Returns null in the event of
+    // failure.
+    static DB getDB() {
+        try {
+            dbSync.acquire();
+            return dbInstance;
+        } catch (InterruptedException e) {
+            return null;
+        }
+    }
+
+    // Release database access lock acquired via getDB().
+    static void releaseDB() {
+        dbSync.release();
+    }
+
     private static final String DATABASE_NAME = "fdroid";
 
     // Possible values of the SQLite flag "synchronous"
@@ -131,7 +157,7 @@ public class DB {
         // To skip compatibility checks, pass null as the checker.
         public Apk getCurrentVersion(DB.Apk.CompatibilityChecker checker) {
 
-            // Try and return the version that's in Google's market first...
+            // Try and return the real current version first...
             if (marketVersion != null && marketVercode > 0) {
                 for (Apk apk : apks) {
                     if (apk.vercode == marketVercode
@@ -140,7 +166,7 @@ public class DB {
                 }
             }
 
-            // If we don't know the market version, or we don't have it, we
+            // If we don't know the current version, or we don't have it, we
             // return the most recent compatible version we have...
             int latestcode = -1;
             Apk latestapk = null;
@@ -396,7 +422,7 @@ public class DB {
     // database.
     private SimpleDateFormat mDateFormat = new SimpleDateFormat("yyyy-MM-dd");
 
-    public DB(Context ctx) {
+    private DB(Context ctx) {
 
         mContext = ctx;
         DBHelper h = new DBHelper(ctx);
@@ -568,12 +594,13 @@ public class DB {
                     app.marketVercode = c.getInt(c
                             .getColumnIndex("marketVercode"));
                     String sAdded = c.getString(c.getColumnIndex("added"));
-                    app.added = (sAdded == null || sAdded.length() == 0) ? null : mDateFormat
+                    app.added = (sAdded == null || sAdded.length() == 0) ? null
-                            .parse(sAdded);
+                            : mDateFormat.parse(sAdded);
                     String sLastUpdated = c.getString(c
                             .getColumnIndex("lastUpdated"));
-                    app.lastUpdated = (sLastUpdated == null || sLastUpdated.length() == 0) ? null
+                    app.lastUpdated = (sLastUpdated == null || sLastUpdated
-                            : mDateFormat.parse(sLastUpdated);
+                            .length() == 0) ? null : mDateFormat
+                            .parse(sLastUpdated);
                     app.hasUpdates = false;
 
                     c2 = db.rawQuery("select * from " + TABLE_APK
@@ -873,8 +900,12 @@ public class DB {
         values.put("trackerURL", upapp.trackerURL);
         values.put("sourceURL", upapp.sourceURL);
         values.put("donateURL", upapp.donateURL);
-        values.put("added", upapp.added == null ? "" : mDateFormat.format(upapp.added));
+        values.put("added",
-        values.put("lastUpdated", upapp.added == null ? "" : mDateFormat.format(upapp.lastUpdated));
+                upapp.added == null ? "" : mDateFormat.format(upapp.added));
+        values.put(
+                "lastUpdated",
+                upapp.added == null ? "" : mDateFormat
+                        .format(upapp.lastUpdated));
         values.put("marketVersion", upapp.marketVersion);
         values.put("marketVercode", upapp.marketVercode);
         values.put("antiFeatures", CommaSeparatedList.str(upapp.antiFeatures));
@@ -907,7 +938,8 @@ public class DB {
         values.put("apkName", upapk.apkName);
         values.put("apkSource", upapk.apkSource);
         values.put("minSdkVersion", upapk.minSdkVersion);
-        values.put("added", upapk.added == null ? "" : mDateFormat.format(upapk.added));
+        values.put("added",
+                upapk.added == null ? "" : mDateFormat.format(upapk.added));
         values.put("permissions", CommaSeparatedList.str(upapk.permissions));
         values.put("features", CommaSeparatedList.str(upapk.features));
         if (oldapk != null) {

src/org/fdroid/fdroid/FDroid.java

@@ -70,8 +70,6 @@ public class FDroid extends TabActivity implements OnItemClickListener,
     private static final int ABOUT = Menu.FIRST + 3;
     private static final int SEARCH = Menu.FIRST + 4;
 
-    private DB db = null;
-
     // Apps that are available to be installed
     private AppListAdapter apps_av = new AppListAdapter(this);
 
@@ -135,14 +133,12 @@ public class FDroid extends TabActivity implements OnItemClickListener,
     @Override
     protected void onStart() {
         super.onStart();
-        db = new DB(this);
         triedEmptyUpdate = false;
         populateLists(true);
     }
 
     @Override
     protected void onStop() {
-        db.close();
         super.onStop();
     }
 
@@ -328,12 +324,19 @@ public class FDroid extends TabActivity implements OnItemClickListener,
 
         long startTime = System.currentTimeMillis();
 
-        // Populate the category list with the real categories, and the locally
+        DB db;
+        Vector<DB.App> apps;
+        String cat_all, cat_whatsnew, cat_recentlyupdated;
+        try {
+            db = DB.getDB();
+
+            // Populate the category list with the real categories, and the
+            // locally
             // generated meta-categories for "All", "What's New" and "Recently
             // Updated"...
-        String cat_all = getString(R.string.category_all);
+            cat_all = getString(R.string.category_all);
-        String cat_whatsnew = getString(R.string.category_whatsnew);
+            cat_whatsnew = getString(R.string.category_whatsnew);
-        String cat_recentlyupdated = getString(R.string.category_recentlyupdated);
+            cat_recentlyupdated = getString(R.string.category_recentlyupdated);
             categories.add(cat_all);
             for (String s : db.getCategories()) {
                 Log.d("FDroid", "s: " + s);
@@ -344,7 +347,11 @@ public class FDroid extends TabActivity implements OnItemClickListener,
             if (currentCategory == null)
                 currentCategory = cat_all;
 
-        Vector<DB.App> apps = db.getApps(null, null, update, true);
+            apps = db.getApps(null, null, update, true);
+        } finally {
+            DB.releaseDB();
+        }
+
         if (apps.isEmpty()) {
             // Don't attempt this more than once - we may have invalid
             // repositories.
@@ -419,6 +426,7 @@ public class FDroid extends TabActivity implements OnItemClickListener,
         public UpdateReceiver(Handler handler) {
             super(handler);
         }
+
         @Override
         protected void onReceiveResult(int resultCode, Bundle resultData) {
             if (resultCode == 1) {
@@ -432,6 +440,7 @@ public class FDroid extends TabActivity implements OnItemClickListener,
                 pd.dismiss();
         }
     }
+
     private UpdateReceiver mUpdateReceiver;
 
     // Force a repo update now. A progress dialog is shown and the UpdateService

src/org/fdroid/fdroid/FDroidApp.java

@@ -22,5 +22,13 @@ import android.app.Application;
 
 public class FDroidApp extends Application {
 
+    @Override
+    public void onCreate() {
+        super.onCreate();
+        
+        DB.initDB(getApplicationContext());
+    }
+
 
 }
+

src/org/fdroid/fdroid/ManageRepo.java

@@ -1,6 +1,6 @@
 /*
+ * Copyright (C) 2010-12  Ciaran Gultnieks, ciaran@ciarang.com
  * Copyright (C) 2009  Roberto Jacinto, roberto.jacinto@caixamagica.pt
- * Copyright (C) 2010  Ciaran Gultnieks, ciaran@ciarang.com
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -44,8 +44,6 @@ import android.widget.SimpleAdapter;
 
 public class ManageRepo extends ListActivity {
 
-    private DB db = null;
-
     private final int ADD_REPO = 1;
     private final int REM_REPO = 2;
 
@@ -59,8 +57,6 @@ public class ManageRepo extends ListActivity {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.repolist);
 
-        db = new DB(this);
-
     }
 
     @Override
@@ -71,7 +67,12 @@ public class ManageRepo extends ListActivity {
     }
 
     private void redraw() {
+        try {
+            DB db = DB.getDB();
             repos = db.getRepos();
+        } finally {
+            DB.releaseDB();
+        }
 
         List<Map<String, Object>> result = new ArrayList<Map<String, Object>>();
         Map<String, Object> server_line;
@@ -104,9 +105,9 @@ public class ManageRepo extends ListActivity {
             result.add(server_line);
         }
         SimpleAdapter show_out = new SimpleAdapter(this, result,
-                R.layout.repolisticons,
+                R.layout.repolisticons, new String[] { "address", "inuse",
-                new String[] { "address", "inuse", "fingerprint" },
+                        "fingerprint" }, new int[] { R.id.uri, R.id.img,
-                new int[] { R.id.uri, R.id.img, R.id.fingerprint });
+                        R.id.fingerprint });
 
         setListAdapter(show_out);
     }
@@ -115,7 +116,12 @@ public class ManageRepo extends ListActivity {
     protected void onListItemClick(ListView l, View v, int position, long id) {
 
         super.onListItemClick(l, v, position, id);
+        try {
+            DB db = DB.getDB();
             db.changeServerStatus(repos.get(position).address);
+        } finally {
+            DB.releaseDB();
+        }
         changed = true;
         redraw();
     }
@@ -150,7 +156,12 @@ public class ManageRepo extends ListActivity {
                             EditText uri = (EditText) alrt
                                     .findViewById(R.id.edit_uri);
                             String uri_str = uri.getText().toString();
+                            try {
+                                DB db = DB.getDB();
                                 db.addServer(uri_str, 10, null);
+                            } finally {
+                                DB.releaseDB();
+                            }
                             changed = true;
                             redraw();
                         }
@@ -180,11 +191,9 @@ public class ManageRepo extends ListActivity {
                         public void onClick(DialogInterface dialog,
                                 int whichButton, boolean isChecked) {
                             if (isChecked) {
-                                rem_lst
+                                rem_lst.addElement(repos.get(whichButton).address);
-                                        .addElement(repos.get(whichButton).address);
                             } else {
-                                rem_lst
+                                rem_lst.removeElement(repos.get(whichButton).address);
-                                        .removeElement(repos.get(whichButton).address);
                             }
                         }
                     });
@@ -192,7 +201,12 @@ public class ManageRepo extends ListActivity {
                     new DialogInterface.OnClickListener() {
                         public void onClick(DialogInterface dialog,
                                 int whichButton) {
+                            try {
+                                DB db = DB.getDB();
                                 db.removeServers(rem_lst);
+                            } finally {
+                                DB.releaseDB();
+                            }
                             changed = true;
                             redraw();
                         }
@@ -217,7 +231,6 @@ public class ManageRepo extends ListActivity {
         if (changed)
             ret.putExtra("update", true);
         this.setResult(RESULT_OK, ret);
-        db.close();
         super.finish();
     }
 

src/org/fdroid/fdroid/SearchResults.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2011  Ciaran Gultnieks, ciaran@ciarang.com
+ * Copyright (C) 2011-12  Ciaran Gultnieks, ciaran@ciarang.com
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -67,8 +67,13 @@ public class SearchResults extends ListActivity {
     }
 
     private void updateView() {
-        DB db = new DB(this);
+        Vector<DB.App> apps;
-        Vector<DB.App> apps = db.getApps(null, mQuery, false, true);
+        try {
+            DB db = DB.getDB();
+            apps = db.getApps(null, mQuery, false, true);
+        } finally {
+            DB.releaseDB();
+        }
         TextView tv = (TextView) findViewById(R.id.description);
         String headertext;
         if(apps.size()==0)
@@ -86,7 +91,6 @@ public class SearchResults extends ListActivity {
         }
         applist.notifyDataSetChanged();
         setListAdapter(applist);
-        db.close();
         
     }
     

src/org/fdroid/fdroid/UpdateService.java

@@ -89,7 +89,7 @@ public class UpdateService extends IntentService {
         // Do the update...
         DB db = null;
         try {
-            db = new DB(getBaseContext());
+            db = DB.getDB();
             boolean notify = prefs.getBoolean("updateNotify", false);
 
             // Get the number of updates available before we
@@ -141,7 +141,7 @@ public class UpdateService extends IntentService {
             }
         } finally {
             if (db != null)
-                db.close();
+                DB.releaseDB();
         }
 
     }