Move Hunspell dictionary loading to worker thread

This change moves the Hunspell dictionary loading to worker thread.

The dictionary loading is relatively heavy task for large dictionary
files, such as Arabic, which can take more than 2 seconds to load on
the Nexus 7 hardware.

The Hunspell worker thread is no longer destroyed and created every
time the dictionary changes, instead the worker thread is re-used.

The dictionary loading happens by adding a new kind of task for the
worker thread. Also, added a special function for clearing all but
dictionary loading tasks from the worker task queue. This is needed
for a special case where the dictionary is still loading while the
user starts typing.

Updated the test cases to take into account changes in delays in
loading the dictionary.

Change-Id: If9be14c7703b39af79f6e3b6708e297a28c49f2f
Reviewed-by: Gatis Paeglis <gatis.paeglis@theqtcompany.com>

1 files changed, 30 insertions, 1 deletions

diff --git a/src/virtualkeyboard/hunspellworker.h b/src/virtualkeyboard/hunspellworker.h
index 789cd6e3..38cc59d8 100644
--- a/src/virtualkeyboard/hunspellworker.h
+++ b/src/virtualkeyboard/hunspellworker.h
@@ -40,6 +40,19 @@ public:
     Hunhandle *hunspell;
 };
 
+class HunspellLoadDictionaryTask : public HunspellTask
+{
+    Q_OBJECT
+public:
+    explicit HunspellLoadDictionaryTask(const QString &locale, const QStringList &searchPaths);
+
+    void run();
+
+    Hunhandle **hunspellPtr;
+    const QString locale;
+    const QStringList searchPaths;
+};
+
 class HunspellWordList
 {
 public:
@@ -85,16 +98,32 @@ class HunspellWorker : public QThread
 {
     Q_OBJECT
 public:
-    explicit HunspellWorker(Hunhandle *hunspell, QObject *parent = 0);
+    explicit HunspellWorker(QObject *parent = 0);
     ~HunspellWorker();
 
     void addTask(QSharedPointer<HunspellTask> task);
     void removeAllTasks();
 
+    template <class X>
+    void removeAllTasksExcept() {
+        QMutexLocker guard(&taskLock);
+        for (int i = 0; i < taskList.size();) {
+            QSharedPointer<X> task(taskList[i].objectCast<X>());
+            if (!task)
+                taskList.removeAt(i);
+            else
+                i++;
+        }
+    }
+
 protected:
     void run();
 
 private:
+    void createHunspell();
+
+private:
+    friend class HunspellLoadDictionaryTask;
     QList<QSharedPointer<HunspellTask> > taskList;
     QSemaphore taskSema;
     QMutex taskLock;