QMimeDatabase: handle removal of a mime directory

The previous commit didn't handle correctly the case where an entire
mime directory is deleted. The unittest wasn't testing that case,
now it is. We need to move providers into a new list, and then
delete those left over (i.e. now unused).

Change-Id: I04fd8b39b511a2331d706864f695ce5074acf916
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/src/corelib/mimetypes/qmimedatabase.cpp b/src/corelib/mimetypes/qmimedatabase.cpp
index 864e9edc61..f90fd12e3b 100644
--- a/src/corelib/mimetypes/qmimedatabase.cpp
+++ b/src/corelib/mimetypes/qmimedatabase.cpp
@@ -104,14 +104,15 @@ void QMimeDatabasePrivate::loadProviders()
         mimeDirs.prepend(QLatin1String(":/qt-project.org/qmime"));
     //qDebug() << "mime dirs:" << mimeDirs;
 
+    QVector<QMimeProviderBase *> currentProviders = m_providers;
+    m_providers.clear();
     m_providers.reserve(mimeDirs.size());
     for (const QString &mimeDir : qAsConst(mimeDirs)) {
         const QString cacheFile = mimeDir + QStringLiteral("/mime.cache");
         QFileInfo fileInfo(cacheFile);
         // Check if we already have a provider for this dir
-        // [This could be optimized by keeping a copy of mimeDirs and comparing the stringlists]
-        const auto it = std::find_if(m_providers.begin(), m_providers.end(), [mimeDir](QMimeProviderBase *prov) { return prov->directory() == mimeDir; });
-        if (it == m_providers.end()) {
+        const auto it = std::find_if(currentProviders.begin(), currentProviders.end(), [mimeDir](QMimeProviderBase *prov) { return prov->directory() == mimeDir; });
+        if (it == currentProviders.end()) {
             QMimeProviderBase *provider = nullptr;
 #if defined(QT_USE_MMAP)
             if (qEnvironmentVariableIsEmpty("QT_NO_MIME_CACHE") && fileInfo.exists()) {
@@ -130,15 +131,17 @@ void QMimeDatabasePrivate::loadProviders()
             m_providers.append(provider);
         } else {
             QMimeProviderBase *provider = *it;
+            currentProviders.erase(it);
             provider->ensureLoaded();
             if (!provider->isValid()) {
                 delete provider;
                 provider = new QMimeXMLProvider(this, mimeDir);
                 //qDebug() << "Created XML provider to replace binary provider for" << mimeDir;
-                *it = provider;
             }
+            m_providers.append(provider);
         }
     }
+    qDeleteAll(currentProviders);
 }
 
 QVector<QMimeProviderBase *> QMimeDatabasePrivate::providers()