MythDownloadManager: Add a cancelDownload method.

Removes the given url from the pending queue and aborts any download
that has already started.

Also invalidate the return data and file pointers for removeListener to
ensure we don't leak memory or disk space for returned results that are
no longer required (should removeListener abort the download as well?)

mythtv/libs/libmythbase/mythdownloadmanager.cpp

@@ -689,7 +689,44 @@ bool MythDownloadManager::downloadNow(MythDownloadInfo *dlInfo, bool deleteInfo)
 
     return success;
 }
-
+
+/** \fn MythDownloadManager::cancelDownload(const QString &)
+ *  \brief Cancel a queued or current download.
+ *  \param url for download to cancel
+ */
+void MythDownloadManager::cancelDownload(const QString &url)
+{
+    QMutexLocker locker(m_infoLock);
+    MythDownloadInfo *dlInfo;
+
+    QMutableListIterator<MythDownloadInfo*> lit(m_downloadQueue);
+    while (lit.hasNext())
+    {
+        lit.next();
+        dlInfo = lit.value();
+        if (dlInfo->m_url == url)
+        {
+            // this shouldn't happen
+            if (dlInfo->m_reply)
+                dlInfo->m_reply->abort();
+            lit.remove();
+            delete dlInfo;
+        }
+    }
+
+    if (m_downloadInfos.contains(url))
+    {
+        dlInfo = m_downloadInfos[url];
+        if (dlInfo->m_reply)
+        {
+            m_downloadReplies.remove(dlInfo->m_reply);
+            dlInfo->m_reply->abort();
+        }
+        m_downloadInfos.remove(url);
+        delete dlInfo;
+    }
+}
+
 /** \fn MythDownloadManager::removeListener(QObject *caller)
  *  \brief Disconnects the specify caller from any existing
  *         MythDownloadInfo instances.
@@ -705,15 +742,23 @@ void MythDownloadManager::removeListener(QObject *caller)
     {
         dlInfo = *lit;
         if (dlInfo->m_caller == caller)
-            dlInfo->m_caller = NULL;
+        {
+            dlInfo->m_caller  = NULL;
+            dlInfo->m_outFile = QString();
+            dlInfo->m_data    = NULL;
+        }
     }
 
     QMap <QString, MythDownloadInfo*>::iterator mit = m_downloadInfos.begin();
     for (; mit != m_downloadInfos.end(); ++mit)
     {
         dlInfo = mit.value();
         if (dlInfo->m_caller == caller)
-            dlInfo->m_caller = NULL;
+        {
+            dlInfo->m_caller  = NULL;
+            dlInfo->m_outFile = QString();
+            dlInfo->m_data    = NULL;
+        }
     }
 }
 

mythtv/libs/libmythbase/mythdownloadmanager.h

@@ -50,6 +50,9 @@ class MBASE_PUBLIC MythDownloadManager : public QObject, public MThread
     bool post(const QString &url, QByteArray *data);
     bool post(QNetworkRequest *req, QByteArray *data);
 
+    // Cancel a download
+    void cancelDownload(const QString &url);
+
     // Generic helpers
     void removeListener(QObject *caller);
     QDateTime GetLastModified(const QString &url);