From 176c9173ae740debc7c46b72040f43772b244c54 Mon Sep 17 00:00:00 2001
From: Henrik Tunedal <tunedal@gmail.com>
Date: Sun, 13 Feb 2011 20:37:35 +0100
Subject: [PATCH] Add preference for SQLite "synchronous" flag

By default SQLite runs with synchronous=FULL, which is the safest mode
and uses fsync() a lot, but this interacts very badly with Samsung's
infamous RFS filesystem. With this preference the user can decide
whether to sacrifice some safety for reasonable performance.
---
 res/values/array.xml          | 13 +++++++++++--
 res/values/strings.xml        |  3 +++
 res/xml/preferences.xml       |  4 ++++
 src/org/fdroid/fdroid/DB.java | 30 ++++++++++++++++++++++++++++++
 4 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/res/values/array.xml b/res/values/array.xml
index 758da0f35..aa3def54d 100644
--- a/res/values/array.xml
+++ b/res/values/array.xml
@@ -7,7 +7,6 @@
 		<item>Every 12 Hours</item>
 		<item>Daily</item>
 	</string-array>
-
 	<string-array name="updateIntervalValues">
 		<item>0</item>
 		<item>1</item>
@@ -16,4 +15,14 @@
 		<item>24</item>
 	</string-array>
 
-</resources>
\ No newline at end of file
+	<string-array name="dbSyncModeNames">
+		<item>Off (unsafe)</item>
+		<item>Normal</item>
+		<item>Full</item>
+	</string-array>
+	<string-array name="dbSyncModeValues">
+		<item>off</item>
+		<item>normal</item>
+		<item>full</item>
+	</string-array>
+</resources>
diff --git a/res/values/strings.xml b/res/values/strings.xml
index b965cb61d..112508ad8 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -124,4 +124,7 @@
 	<string name="expert_mode">Enable expert mode</string>
 
 <string name="search_hint">Search applications</string>
+
+	<string name="db_sync_mode">Database sync mode</string>
+	<string name="db_sync_mode_long">Set the value of SQLite\'s "synchronous" flag</string>
 </resources>
diff --git a/res/xml/preferences.xml b/res/xml/preferences.xml
index d82b5164a..8cb05494e 100644
--- a/res/xml/preferences.xml
+++ b/res/xml/preferences.xml
@@ -4,6 +4,10 @@
 		<CheckBoxPreference android:title="@string/cache_downloaded"
 			android:defaultValue="false" android:summary="@string/keep_downloaded"
 			android:key="cacheDownloaded" />
+		<ListPreference android:title="@string/db_sync_mode"
+			android:summary="@string/db_sync_mode_long" android:key="dbSyncMode"
+			android:defaultValue="full" android:entries="@array/dbSyncModeNames"
+			android:entryValues="@array/dbSyncModeValues" />
 	</PreferenceCategory>
 	<PreferenceCategory android:title="@string/updates">
 		<ListPreference android:title="@string/automatic_repo_scan"
diff --git a/src/org/fdroid/fdroid/DB.java b/src/org/fdroid/fdroid/DB.java
index aa3de3511..96fedc77c 100644
--- a/src/org/fdroid/fdroid/DB.java
+++ b/src/org/fdroid/fdroid/DB.java
@@ -39,6 +39,11 @@ public class DB {
 
     private static final String DATABASE_NAME = "fdroid";
 
+    // Possible values of the SQLite flag "synchronous"
+    public static final int SYNC_OFF = 0;
+    public static final int SYNC_NORMAL = 1;
+    public static final int SYNC_FULL = 2;
+
     private SQLiteDatabase db;
 
     // The TABLE_APP table stores details of all the applications we know about.
@@ -266,6 +271,19 @@ public class DB {
         DBHelper h = new DBHelper(ctx);
         db = h.getWritableDatabase();
         mPm = ctx.getPackageManager();
+        SharedPreferences prefs = PreferenceManager
+            .getDefaultSharedPreferences(mContext);
+        String sync_mode = prefs.getString("dbSyncMode", null);
+        if ("off".equals(sync_mode))
+            setSynchronizationMode(SYNC_OFF);
+        else if ("normal".equals(sync_mode))
+            setSynchronizationMode(SYNC_NORMAL);
+        else if ("full".equals(sync_mode))
+            setSynchronizationMode(SYNC_FULL);
+        else
+            sync_mode = null;
+        if (sync_mode != null)
+            Log.d("FDroid", "Database synchronization mode: " + sync_mode);
     }
 
     public void close() {
@@ -683,4 +701,16 @@ public class DB {
             db.delete(TABLE_REPO, "address = ?", new String[] { address });
         }
     }
+
+    public int getSynchronizationMode() {
+        Cursor cursor = db.rawQuery("PRAGMA synchronous", null);
+        cursor.moveToFirst();
+        int mode = cursor.getInt(0);
+        cursor.close();
+        return mode;
+    }
+
+    public void setSynchronizationMode(int mode) {
+        db.execSQL("PRAGMA synchronous = " + mode);
+    }
 }