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, 43 insertions, 5 deletions

diff --git a/tests/benchmarks/corelib/io/qfile/main.cpp b/tests/benchmarks/corelib/io/qfile/main.cpp
index 3d16921b7f..02922e0bbd 100644
--- a/tests/benchmarks/corelib/io/qfile/main.cpp
+++ b/tests/benchmarks/corelib/io/qfile/main.cpp
@@ -41,10 +41,11 @@
 
 #include <QDebug>
 #include <QTemporaryFile>
-#include <QFSFileEngine>
 #include <QString>
 #include <QDirIterator>
 
+#include <private/qfsfileengine_p.h>
+
 #include <qtest.h>
 
 #include <stdio.h>
@@ -79,7 +80,9 @@ Q_OBJECT
 public:
     enum BenchmarkType {
         QFileBenchmark = 1,
+#ifdef QT_BUILD_INTERNAL
         QFSFileEngineBenchmark,
+#endif
         Win32Benchmark,
         PosixBenchmark,
         QFileFromPosixBenchmark
@@ -173,7 +176,14 @@ void tst_qfile::cleanupTestCase()
 }
 
 void tst_qfile::readBigFile_QFile() { readBigFile(); }
-void tst_qfile::readBigFile_QFSFileEngine() { readBigFile(); }
+void tst_qfile::readBigFile_QFSFileEngine()
+{
+#ifdef QT_BUILD_INTERNAL
+    readBigFile();
+#else
+    QSKIP("This test requires -developer-build.");
+#endif
+}
 void tst_qfile::readBigFile_posix() 
 { 
     readBigFile(); 
@@ -191,10 +201,15 @@ void tst_qfile::readBigFile_QFile_data()
 
 void tst_qfile::readBigFile_QFSFileEngine_data()
 {
+#ifdef QT_BUILD_INTERNAL
     readBigFile_data(QFSFileEngineBenchmark, QIODevice::NotOpen, QIODevice::NotOpen);
     readBigFile_data(QFSFileEngineBenchmark, QIODevice::NotOpen, QIODevice::Unbuffered);
     readBigFile_data(QFSFileEngineBenchmark, QIODevice::Text, QIODevice::NotOpen);
     readBigFile_data(QFSFileEngineBenchmark, QIODevice::Text, QIODevice::Unbuffered);
+#else
+    QTest::addColumn<int>("dummy");
+    QTest::newRow("Test will be skipped") << -1;
+#endif
 }
 
 void tst_qfile::readBigFile_posix_data()
@@ -255,6 +270,7 @@ void tst_qfile::readBigFile()
             file.close();
         }
         break;
+#ifdef QT_BUILD_INTERNAL
         case(QFSFileEngineBenchmark): {
             QFSFileEngine fse(filename);
             fse.open(QIODevice::ReadOnly|textMode|bufferedMode);
@@ -266,6 +282,7 @@ void tst_qfile::readBigFile()
             fse.close();
         }
         break;
+#endif
         case(PosixBenchmark): {
             QByteArray data = filename.toLocal8Bit();
             const char* cfilename = data.constData();
@@ -317,7 +334,9 @@ void tst_qfile::seek_data()
 {
     QTest::addColumn<tst_qfile::BenchmarkType>("testType");
     QTest::newRow("QFile") << QFileBenchmark;
+#ifdef QT_BUILD_INTERNAL
     QTest::newRow("QFSFileEngine") << QFSFileEngineBenchmark;
+#endif
     QTest::newRow("Posix FILE*") << PosixBenchmark;
 #ifdef Q_OS_WIN
     QTest::newRow("Win32 API") << Win32Benchmark;
@@ -343,6 +362,7 @@ void tst_qfile::seek()
             file.close();
         }
         break;
+#ifdef QT_BUILD_INTERNAL
         case(QFSFileEngineBenchmark): {
             QFSFileEngine fse(filename);
             fse.open(QIODevice::ReadOnly);
@@ -353,6 +373,7 @@ void tst_qfile::seek()
             fse.close();
         }
         break;
+#endif
         case(PosixBenchmark): {
             QByteArray data = filename.toLocal8Bit();
             const char* cfilename = data.constData();
@@ -396,7 +417,9 @@ void tst_qfile::open_data()
 {
     QTest::addColumn<tst_qfile::BenchmarkType>("testType");
     QTest::newRow("QFile") << QFileBenchmark;
+#ifdef QT_BUILD_INTERNAL
     QTest::newRow("QFSFileEngine") << QFSFileEngineBenchmark;
+#endif
     QTest::newRow("Posix FILE*") << PosixBenchmark;
     QTest::newRow("QFile from FILE*") << QFileFromPosixBenchmark;
 #ifdef Q_OS_WIN
@@ -419,6 +442,7 @@ void tst_qfile::open()
             }
         }
         break;
+#ifdef QT_BUILD_INTERNAL
         case(QFSFileEngineBenchmark): {
             QBENCHMARK {
                 QFSFileEngine fse(filename);
@@ -427,7 +451,7 @@ void tst_qfile::open()
             }
         }
         break;
-
+#endif
         case(PosixBenchmark): {
             // ensure we don't account toLocal8Bit()
             QByteArray data = filename.toLocal8Bit();
@@ -477,7 +501,14 @@ void tst_qfile::open()
 
 
 void tst_qfile::readSmallFiles_QFile() { readSmallFiles(); }
-void tst_qfile::readSmallFiles_QFSFileEngine() { readSmallFiles(); }
+void tst_qfile::readSmallFiles_QFSFileEngine()
+{
+#ifdef QT_BUILD_INTERNAL
+    readSmallFiles();
+#else
+    QSKIP("This test requires -developer-build.");
+#endif
+}
 void tst_qfile::readSmallFiles_posix() 
 {
     readSmallFiles(); 
@@ -498,10 +529,15 @@ void tst_qfile::readSmallFiles_QFile_data()
 
 void tst_qfile::readSmallFiles_QFSFileEngine_data()
 {
+#ifdef QT_BUILD_INTERNAL
     readSmallFiles_data(QFSFileEngineBenchmark, QIODevice::NotOpen, QIODevice::NotOpen);
     readSmallFiles_data(QFSFileEngineBenchmark, QIODevice::NotOpen, QIODevice::Unbuffered);
     readSmallFiles_data(QFSFileEngineBenchmark, QIODevice::Text, QIODevice::NotOpen);
     readSmallFiles_data(QFSFileEngineBenchmark, QIODevice::Text, QIODevice::Unbuffered);
+#else
+    QTest::addColumn<int>("dummy");
+    QTest::newRow("Test will be skipped") << -1;
+#endif
 }
 
 void tst_qfile::readSmallFiles_posix_data()
@@ -606,6 +642,7 @@ void tst_qfile::readSmallFiles()
             }
         }
         break;
+#ifdef QT_BUILD_INTERNAL
         case(QFSFileEngineBenchmark): {
             QList<QFSFileEngine*> fileList;
             Q_FOREACH(QString file, files) {
@@ -626,6 +663,7 @@ void tst_qfile::readSmallFiles()
             }
         }
         break;
+#endif
         case(PosixBenchmark): {
             QList<FILE*> fileList;
             Q_FOREACH(QString file, files) {
diff --git a/tests/benchmarks/corelib/io/qfile/qfile.pro b/tests/benchmarks/corelib/io/qfile/qfile.pro
index 933469071d..5f7b9af73f 100644
--- a/tests/benchmarks/corelib/io/qfile/qfile.pro
+++ b/tests/benchmarks/corelib/io/qfile/qfile.pro
@@ -1,6 +1,6 @@
 TEMPLATE = app
 TARGET = tst_bench_qfile
-QT = core testlib
+QT = core core-private testlib
 win32: DEFINES+= _CRT_SECURE_NO_WARNINGS
 
 SOURCES += main.cpp