Merge lp:~phablet-team/history-service/single_instance_using_lock_file into lp:history-service/staging

[Gustavo Pichorim Boiko]

Use a QLockFile to ensure there will be only one instance of the daemon per user.
As we now delay the registration on dbus, sometimes we ended up having two instances of the daeon running (because of dbus activation). This change makes sure that won't happen.

Use a QLockFile to ensure there will be only one instance of the daemon per user.
As we now delay the registration on dbus, sometimes we ended up having two instances of the daeon running (because of dbus activation). This change makes sure that won't happen.

[lp:~phablet-team/history-service/single_instance_using_lock_file]

274. By Gustavo Pichorim Boiko on 2017-03-08

Make sure tests use different lock files so that they can run simultaneously

275. By Tiago Salem Herrmann on 2017-03-08

merge parent branch

276. By Tiago Salem Herrmann on 2017-03-09

merge parent branch

277. By Gustavo Pichorim Boiko on 2017-03-09

History-daemon is not a system service, so store a lock somewhere in the user's home
directory to allow running one instance per user.

[Tiago Salem Herrmann (tiagosh)]

Looks good to me.
good to have this finally resolved.

review: Approve

=== modified file 'cmake/modules/GenerateTest.cmake'
--- cmake/modules/GenerateTest.cmake	2015-09-28 14:26:09 +0000
+++ cmake/modules/GenerateTest.cmake	2017-03-09 22:20:18 +0000
@@ -79,6 +79,7 @@
                 set(ARG_ENVIRONMENT HOME=${TMPDIR}
                                     HISTORY_PLUGIN_PATH=${CMAKE_BINARY_DIR}/plugins/sqlite
                                     HISTORY_SQLITE_DBPATH=:memory:
+                                    HISTORY_LOCK_FILE=${TMPDIR}/history-service.lock
                                     MC_ACCOUNT_DIR=${TMPDIR}
                                     MC_MANAGER_DIR=${TMPDIR})
             endif ()

=== modified file 'daemon/main.cpp'
--- daemon/main.cpp	2016-03-30 14:03:29 +0000
+++ daemon/main.cpp	2017-03-09 22:20:18 +0000
@@ -20,16 +20,26 @@
  */
 
 #include "historydaemon.h"
+#include <QLockFile>
+#include <QDir>
 
 bool checkApplicationRunning()
 {
-    bool result = false;
-    QDBusReply<bool> reply = QDBusConnection::sessionBus().interface()->isServiceRegistered(History::DBusService);
-    if (reply.isValid()) {
-        result = reply.value();
+    QString lockPath = qgetenv("HISTORY_LOCK_FILE");
+    if (lockPath.isEmpty()) {
+        lockPath = QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation);
+        QDir dir(lockPath);
+        if (!dir.exists("history-service") && !dir.mkpath("history-service")) {
+            qCritical() << "Failed to create dir";
+            // in case we fail to create the lock, better not even start the application
+            return true;
+        }
+        dir.cd("history-service");
+        lockPath = dir.absoluteFilePath("history-daemon.lock");
     }
 
-    return result;
+    static QLockFile *lockFile = new QLockFile(lockPath);
+    return !lockFile->tryLock();
 }
 int main(int argc, char **argv)
 {