Ensure that QTemporaryFile clears all file mappings.

Factor out code to clear all mappings into
QFSFileEnginePrivate::unmapAll() and call that
from QTemporaryFile.

Task-number: QTBUG-39976
Change-Id: Ic1ceeba0ba4451866f1081fee430e5c458c0819d
Reviewed-by: Jonathan Liu <net147@gmail.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/io/qfsfileengine.cpp

@@ -179,9 +179,7 @@ QFSFileEngine::~QFSFileEngine()
             } while (ret == -1 && errno == EINTR);
         }
     }
-    QList<uchar*> keys = d->maps.keys();
-    for (int i = 0; i < keys.count(); ++i)
-        unmap(keys.at(i));
+    d->unmapAll();
 }
 
 /*!
@@ -463,6 +461,18 @@ qint64 QFSFileEngine::size() const
     return d->nativeSize();
 }
 
+/*!
+    \internal
+*/
+void QFSFileEnginePrivate::unmapAll()
+{
+    if (!maps.isEmpty()) {
+        const QList<uchar*> keys = maps.keys(); // Make a copy since unmap() modifies the map.
+        for (int i = 0; i < keys.count(); ++i)
+            unmap(keys.at(i));
+    }
+}
+
 #ifndef Q_OS_WIN
 /*!
     \internal

src/corelib/io/qfsfileengine_p.h

@@ -175,6 +175,7 @@ public:
 
     uchar *map(qint64 offset, qint64 size, QFile::MemoryMapFlags flags);
     bool unmap(uchar *ptr);
+    void unmapAll();
 
     mutable QFileSystemMetaData metaData;
 

src/corelib/io/qtemporaryfile.cpp

@@ -235,6 +235,8 @@ static bool createFileFromTemplate(NativeFileHandle &file,
 //************* QTemporaryFileEngine
 QTemporaryFileEngine::~QTemporaryFileEngine()
 {
+    Q_D(QFSFileEngine);
+    d->unmapAll();
     QFSFileEngine::close();
 }
 
@@ -363,6 +365,7 @@ bool QTemporaryFileEngine::remove()
     Q_D(QFSFileEngine);
     // Since the QTemporaryFileEngine::close() does not really close the file,
     // we must explicitly call QFSFileEngine::close() before we remove it.
+    d->unmapAll();
     QFSFileEngine::close();
     if (QFSFileEngine::remove()) {
         d->fileEntry.clear();

tests/auto/corelib/io/qtemporaryfile/tst_qtemporaryfile.cpp

@@ -251,6 +251,11 @@ void tst_QTemporaryFile::autoRemove()
         QTemporaryFile file("tempXXXXXX");
         QVERIFY(file.open());
         fileName = file.fileName();
+        // QTBUG-39976, file mappings should be cleared as well.
+        QVERIFY(file.write("test"));
+        QVERIFY(file.flush());
+        uchar *mapped = file.map(0, file.size());
+        QVERIFY(mapped);
         file.close();
     }
     QVERIFY(!QFile::exists(fileName));