Merge lp:~jamesh/mediascanner2/qml-no-db-available into lp:mediascanner2

[James Henstridge]

If the mediascanner index can not be opened, catch the exception in the QML plugin and act as if the database is empty. A warning is printed via Qt's logging framework. This prevents QML apps using mediascanner from terminating if there is a problem opening the media index.

If the mediascanner index can not be opened, allow construction of the QML MediaScannerWrapper class to succeed. Letting the exception propagate causes QML apps to terminate, so is not a helpful behaviour.

With this change, we now:

1. print a warning on construction.
2. print a warning if the MediaStoreWrapper's lookup() or query() methods are called and return zero/empty results.
3. Make the various model classes behave as if they are empty.

[PS Jenkins bot (ps-jenkins)]

PASSED: Continuous integration, rev:319
http://jenkins.qa.ubuntu.com/job/mediascanner2-ci/203/
Executed test runs:
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mediascanner2-vivid-amd64-ci/40
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mediascanner2-vivid-armhf-ci/40
        deb: http://jenkins.qa.ubuntu.com/job/mediascanner2-vivid-armhf-ci/40/artifact/work/output/*zip*/output.zip
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mediascanner2-vivid-i386-ci/40
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mediascanner2-wily-amd64-ci/15
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mediascanner2-wily-armhf-ci/15
        deb: http://jenkins.qa.ubuntu.com/job/mediascanner2-wily-armhf-ci/15/artifact/work/output/*zip*/output.zip
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mediascanner2-wily-i386-ci/15

Click here to trigger a rebuild:
http://s-jenkins.ubuntu-ci:8080/job/mediascanner2-ci/203/rebuild

review: Approve (continuous-integration)

[Michi Henning (michihenning)]

Looks great!

review: Approve

[Michi Henning (michihenning)]

Cool thanks!

review: Approve

=== modified file 'src/extractor/CMakeLists.txt'
--- src/extractor/CMakeLists.txt	2015-10-22 08:19:07 +0000
+++ src/extractor/CMakeLists.txt	2015-12-15 04:28:24 +0000
@@ -12,7 +12,11 @@
   OUTPUT dbus-generated.c dbus-generated.h
   COMMAND ${gdbus_codegen} --interface-prefix=com.canonical.MediaScanner2 --generate-c-code dbus-generated --c-namespace MS ${CMAKE_CURRENT_SOURCE_DIR}/dbus-interface.xml
   MAIN_DEPENDENCY dbus-interface.xml
-)
+  )
+# Code generated by gdbus-codegen doesn't like all the warning flags
+# we have turned on.
+set_property(SOURCE dbus-generated.c APPEND_STRING PROPERTY
+  COMPILE_FLAGS " -Wno-unused-parameter -Wno-pedantic")
 
 # The client code for the extractor daemon
 add_library(extractor-client STATIC

=== modified file 'src/qml/Ubuntu/MediaScanner.0.1/MediaStoreWrapper.cc'
--- src/qml/Ubuntu/MediaScanner.0.1/MediaStoreWrapper.cc	2014-08-21 03:55:40 +0000
+++ src/qml/Ubuntu/MediaScanner.0.1/MediaStoreWrapper.cc	2015-12-15 04:28:24 +0000
@@ -46,10 +46,14 @@
 MediaStoreWrapper::MediaStoreWrapper(QObject *parent)
     : QObject(parent) {
     const char *use_dbus = getenv("MEDIASCANNER_USE_DBUS");
-    if (use_dbus != nullptr && !strcmp(use_dbus, "1")) {
-        store.reset(new mediascanner::dbus::ServiceStub(the_session_bus()));
-    } else {
-        store.reset(new mediascanner::MediaStore(MS_READ_ONLY));
+    try {
+        if (use_dbus != nullptr && !strcmp(use_dbus, "1")) {
+            store.reset(new mediascanner::dbus::ServiceStub(the_session_bus()));
+        } else {
+            store.reset(new mediascanner::MediaStore(MS_READ_ONLY));
+        }
+    } catch (const std::exception &e) {
+        qWarning() << "Could not initialise media store:" << e.what();
     }
 
     QDBusConnection::sessionBus().connect(
@@ -61,6 +65,11 @@
 }
 
 QList<QObject*> MediaStoreWrapper::query(const QString &q, MediaType type) {
+    if (!store) {
+        qWarning() << "query() called on invalid MediaStore";
+        return QList<QObject*>();
+    }
+
     QList<QObject*> result;
     try {
         for (const auto &media : store->query(q.toStdString(), static_cast<mediascanner::MediaType>(type), mediascanner::Filter())) {
@@ -75,6 +84,11 @@
 }
 
 MediaFileWrapper *MediaStoreWrapper::lookup(const QString &filename) {
+    if (!store) {
+        qWarning() << "lookup() called on invalid MediaStore";
+        return nullptr;
+    }
+
     MediaFileWrapper *wrapper;
     try {
         wrapper = new MediaFileWrapper(store->lookup(filename.toStdString()));

=== modified file 'src/qml/Ubuntu/MediaScanner.0.1/StreamingModel.cc'
--- src/qml/Ubuntu/MediaScanner.0.1/StreamingModel.cc	2014-08-15 11:05:47 +0000
+++ src/qml/Ubuntu/MediaScanner.0.1/StreamingModel.cc	2015-12-15 04:28:24 +0000
@@ -104,7 +104,7 @@
 }
 
 void StreamingModel::updateModel() {
-    if (store.isNull()) {
+    if (store.isNull() || !store->store) {
         query_future = QFuture<void>();
         setStatus(Ready);
         return;

=== modified file 'test/CMakeLists.txt'
--- test/CMakeLists.txt	2015-10-22 10:13:51 +0000
+++ test/CMakeLists.txt	2015-12-15 04:28:24 +0000
@@ -78,6 +78,11 @@
   ENVIRONMENT "QT_QPA_PLATFORM=minimal;MEDIASCANNER_USE_DBUS=1"
   TIMEOUT 600)
 
+add_test(test_qml_nodb qmltestrunner -import ${CMAKE_BINARY_DIR}/src/qml -input ${CMAKE_CURRENT_SOURCE_DIR}/test_qml_nodb.qml)
+set_tests_properties(test_qml_nodb PROPERTIES
+  ENVIRONMENT "QT_QPA_PLATFORM=minimal;MEDIASCANNER_CACHEDIR=${CMAKE_CURRENT_BINARY_DIR}/qml-nodb-cachedir;DBUS_SESSION_BUS_ADDRESS="
+  TIMEOUT 600)
+
 
 add_executable(test_util test_util.cc ../src/mediascanner/utils.cc)
 target_link_libraries(test_util gtest ${GLIB_LDFLAGS})

=== added file 'test/test_qml_nodb.qml'
--- test/test_qml_nodb.qml	1970-01-01 00:00:00 +0000
+++ test/test_qml_nodb.qml	2015-12-15 04:28:24 +0000
@@ -0,0 +1,38 @@
+import QtQuick 2.0
+import QtTest 1.0
+import Ubuntu.MediaScanner 0.1
+
+TestCase {
+    id: root
+    name: "NoDatabaseTests"
+
+    function test_mediastore() {
+        ignoreWarning("Could not initialise media store: unable to open database file");
+        var store = Qt.createQmlObject(
+            "import Ubuntu.MediaScanner 0.1;" +
+            "MediaStore {}", root);
+        if (store === null) {
+            fail("Could not create MediaStore component");
+        }
+
+        ignoreWarning("query() called on invalid MediaStore");
+        compare(store.query("foo", MediaStore.AllMedia), []);
+
+        ignoreWarning("lookup() called on invalid MediaStore");
+        compare(store.lookup("/some/file"), null);
+    }
+
+    function test_songsmodel() {
+        ignoreWarning("Could not initialise media store: unable to open database file");
+        var model = Qt.createQmlObject(
+            "import Ubuntu.MediaScanner 0.1;" +
+            "SongsModel {" +
+            "  store: MediaStore {}" +
+            "}", root);
+        if (model === null) {
+            fail("Could not create SongsModel component");
+        }
+        // Model is empty
+        compare(model.count, 0);
+    }
+}