Issue 6372: Add preference for setting timezone to UTC.

This is a privacy preference to avoid leaking your current location while
replying to email.

res/values/strings.xml

@@ -332,6 +332,7 @@ Please submit bug reports, contribute new features and ask questions at
     <string name="global_settings_confirm_action_delete_notif">Delete (from notification)</string>
 
     <string name="global_settings_privacy_hide_useragent">Remove K-9 User-Agent from mail headers</string>
+    <string name="global_settings_privacy_hide_timezone">Use UTC as time zone in mail headers</string>
     <string name="global_settings_notification_hide_subject_title">Hide subject in notifications</string>
     <string name="global_settings_notification_hide_subject_never">Never</string>
     <string name="global_settings_notification_hide_subject_when_locked">When device is locked</string>

res/xml/global_preferences.xml

@@ -383,6 +383,11 @@
             android:key="privacy_hide_useragent"
             android:title="@string/global_settings_privacy_hide_useragent"/>
 
+        <CheckBoxPreference
+            android:persistent="false"
+            android:key="privacy_hide_timezone"
+            android:title="@string/global_settings_privacy_hide_timezone"/>
+
     </PreferenceScreen>
 
     <PreferenceScreen

src/com/fsck/k9/K9.java

@@ -263,6 +263,7 @@ public class K9 extends Application {
     private static String mAttachmentDefaultPath = "";
     private static boolean mWrapFolderNames = false;
     private static boolean mHideUserAgent = false;
+    private static boolean mHideTimeZone = false;
 
     private static boolean useGalleryBugWorkaround = false;
     private static boolean galleryBuggy;
@@ -537,6 +538,7 @@ public class K9 extends Application {
         editor.putBoolean("messageViewShowNext", mMessageViewShowNext);
         editor.putBoolean("wrapFolderNames", mWrapFolderNames);
         editor.putBoolean("hideUserAgent", mHideUserAgent);
+        editor.putBoolean("hideTimeZone", mHideTimeZone);
 
         editor.putString("language", language);
         editor.putInt("theme", theme.ordinal());
@@ -748,6 +750,7 @@ public class K9 extends Application {
         mMessageViewShowNext = sprefs.getBoolean("messageViewShowNext", false);
         mWrapFolderNames = sprefs.getBoolean("wrapFolderNames", false);
         mHideUserAgent = sprefs.getBoolean("hideUserAgent", false);
+        mHideTimeZone = sprefs.getBoolean("hideTimeZone", false);
 
         useGalleryBugWorkaround = sprefs.getBoolean("useGalleryBugWorkaround", K9.isGalleryBuggy());
 
@@ -1284,6 +1287,13 @@ public class K9 extends Application {
         mHideUserAgent = state;
     }
 
+    public static boolean hideTimeZone() {
+        return mHideTimeZone;
+    }
+    public static void setHideTimeZone(final boolean state) {
+        mHideTimeZone = state;
+    }
+
     public static String getAttachmentDefaultPath() {
         return mAttachmentDefaultPath;
     }

src/com/fsck/k9/activity/setup/Prefs.java

@@ -86,6 +86,7 @@ public class Prefs extends K9PreferenceActivity {
     private static final String PREFERENCE_QUIET_TIME_ENDS = "quiet_time_ends";
     private static final String PREFERENCE_NOTIF_QUICK_DELETE = "notification_quick_delete";
     private static final String PREFERENCE_HIDE_USERAGENT = "privacy_hide_useragent";
+    private static final String PREFERENCE_HIDE_TIMEZONE = "privacy_hide_timezone";
 
     private static final String PREFERENCE_MESSAGEVIEW_MOBILE_LAYOUT = "messageview_mobile_layout";
     private static final String PREFERENCE_AUTOFIT_WIDTH = "messageview_autofit_width";
@@ -142,6 +143,7 @@ public class Prefs extends K9PreferenceActivity {
     private CheckBoxPreference mDebugLogging;
     private CheckBoxPreference mSensitiveLogging;
     private CheckBoxPreference mHideUserAgent;
+    private CheckBoxPreference mHideTimeZone;
     private CheckBoxPreference mWrapFolderNames;
     private CheckBoxListPreference mVisibleRefileActions;
 
@@ -385,10 +387,12 @@ public class Prefs extends K9PreferenceActivity {
         mDebugLogging = (CheckBoxPreference)findPreference(PREFERENCE_DEBUG_LOGGING);
         mSensitiveLogging = (CheckBoxPreference)findPreference(PREFERENCE_SENSITIVE_LOGGING);
         mHideUserAgent = (CheckBoxPreference)findPreference(PREFERENCE_HIDE_USERAGENT);
+        mHideTimeZone = (CheckBoxPreference)findPreference(PREFERENCE_HIDE_TIMEZONE);
 
         mDebugLogging.setChecked(K9.DEBUG);
         mSensitiveLogging.setChecked(K9.DEBUG_SENSITIVE);
         mHideUserAgent.setChecked(K9.hideUserAgent());
+        mHideTimeZone.setChecked(K9.hideTimeZone());
 
         mAttachmentPathPreference = findPreference(PREFERENCE_ATTACHMENT_DEF_PATH);
         mAttachmentPathPreference.setSummary(K9.getAttachmentDefaultPath());
@@ -537,6 +541,7 @@ public class Prefs extends K9PreferenceActivity {
         K9.DEBUG = mDebugLogging.isChecked();
         K9.DEBUG_SENSITIVE = mSensitiveLogging.isChecked();
         K9.setHideUserAgent(mHideUserAgent.isChecked());
+        K9.setHideTimeZone(mHideTimeZone.isChecked());
 
         Editor editor = preferences.edit();
         K9.save(editor);

src/com/fsck/k9/mail/internet/MimeMessage.java

@@ -8,6 +8,7 @@ import java.io.OutputStream;
 import java.io.OutputStreamWriter;
 import java.text.SimpleDateFormat;
 import java.util.Date;
+import java.util.TimeZone;
 import java.util.LinkedList;
 import java.util.Locale;
 import java.util.Set;
@@ -33,6 +34,7 @@ import com.fsck.k9.mail.MessagingException;
 import com.fsck.k9.mail.Multipart;
 import com.fsck.k9.mail.Part;
 import com.fsck.k9.mail.store.UnavailableStorageException;
+import com.fsck.k9.K9;
 
 /**
  * An implementation of Message that stores all of it's metadata in RFC 822 and
@@ -150,6 +152,11 @@ public class MimeMessage extends Message {
         if (mDateFormat == null) {
             mDateFormat = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss Z", Locale.US);
         }
+
+        if (K9.hideTimeZone()) {
+            mDateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
+        }
+
         addHeader("Date", mDateFormat.format(sentDate));
         setInternalSentDate(sentDate);
     }

src/com/fsck/k9/preferences/GlobalSettings.java

@@ -252,6 +252,9 @@ public class GlobalSettings {
         s.put("hideUserAgent", Settings.versions(
                 new V(32, new BooleanSetting(false))
             ));
+        s.put("hideTimeZone", Settings.versions(
+                new V(32, new BooleanSetting(false))
+            ));
 
         SETTINGS = Collections.unmodifiableMap(s);