Drop file-engine abstraction from public API

This abstraction imposed serious performance penalties and is being
dropped from the public API.

In particular, by allowing file names to be arbitrarily hijacked by
different file engines, and requiring engines to be instantiated in
order to decide, it imposed unnecessary overhead on all file operations.

Another flaw in the design with direct impact on performance is how
engines have no way to provide (or retain) additional information
obtained when querying the filesystem. In many places this has meant
repeated operations on the file system, where useful information is
immediately discarded to be queried again subsequently.

For Qt 4.8 a major refactoring of the code base took place to allow
bypassing the file-engine abstraction in select places, with
considerable performance gains observed. In Qt 5 it is expected we'll be
able to take this further, reaping even more benefits, but the
abstraction has to go.

[Dropping this now does not preclude that virtual file systems make an
appearance in Qt at a later point in Qt 5's lifecycle. Hopefully with a
new and improved abstraction.]

Forward declarations for QFileExtension(Result) were dropped, as the
classes were never used or defined.

Tests using "internalized" classes will only fully run on developer
builds. QFSFileEngine was removed altogether from exception safety test,
as it isn't its intent to test internal API.

Change-Id: Ie910e6c2628be202ea9e05366b091d6d529b246b
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>

2 files changed, 9 insertions, 1 deletions

diff --git a/tests/auto/corelib/io/qdiriterator/qdiriterator.pro b/tests/auto/corelib/io/qdiriterator/qdiriterator.pro
index cfb3201c43..ef59fc48e3 100644
--- a/tests/auto/corelib/io/qdiriterator/qdiriterator.pro
+++ b/tests/auto/corelib/io/qdiriterator/qdiriterator.pro
@@ -1,6 +1,6 @@
 CONFIG += testcase parallel_test
 TARGET = tst_qdiriterator
-QT = core testlib
+QT = core-private core testlib
 SOURCES = tst_qdiriterator.cpp
 RESOURCES += qdiriterator.qrc
 
diff --git a/tests/auto/corelib/io/qdiriterator/tst_qdiriterator.cpp b/tests/auto/corelib/io/qdiriterator/tst_qdiriterator.cpp
index d5d490dc29..37d3e1ab68 100644
--- a/tests/auto/corelib/io/qdiriterator/tst_qdiriterator.cpp
+++ b/tests/auto/corelib/io/qdiriterator/tst_qdiriterator.cpp
@@ -48,6 +48,8 @@
 #include <qfileinfo.h>
 #include <qstringlist.h>
 
+#include <QtCore/private/qfsfileengine_p.h>
+
 #if defined(Q_OS_VXWORKS)
 #define Q_NO_SYMLINKS
 #endif
@@ -454,6 +456,7 @@ void tst_QDirIterator::stopLinkLoop()
     // The goal of this test is only to ensure that the test above don't malfunction
 }
 
+#ifdef QT_BUILD_INTERNAL
 class EngineWithNoIterator : public QFSFileEngine
 {
 public:
@@ -473,13 +476,18 @@ public:
         return new EngineWithNoIterator(fileName);
     }
 };
+#endif
 
 void tst_QDirIterator::engineWithNoIterator()
 {
+#ifdef QT_BUILD_INTERNAL
     EngineWithNoIteratorHandler handler;
 
     QDir("entrylist").entryList();
     QVERIFY(true); // test that the above line doesn't crash
+#else
+    QSKIP("This test requires -developer-build.");
+#endif
 }
 
 void tst_QDirIterator::absoluteFilePathsFromRelativeIteratorPath()