QDirIterator: add nextFileInfo()

Before this change, next() was the only way to advance the iterator,
whether the caller was ultimately interested in just the filePath()
(good) or not (bad luck, had to call .fileInfo()).

Add a new function, nextFileInfo(), with returns fileInfo() instead.
Incidentally, the returned object has already been constructed as part
of advance()ing the iterator, so the new function is faster than
next() even if the result is ignored, because we're not calculating a
QString result the caller may not be interested in.

Use the new function around the code.

Fix a couple of cases of next(); fileInfo().filePath() (just use
next()'s return value) as a drive-by.

[ChangeLog][QtCore][QDirIterator] Added nextFileInfo(), which is like
next(), but returns fileInfo() instead of filePath().

Change-Id: I601220575961169b44139fc55b9eae6c3197afb4
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

20 files changed, 72 insertions, 82 deletions

diff --git a/qmake/generators/win32/msvc_nmake.cpp b/qmake/generators/win32/msvc_nmake.cpp
index cf58ead2e9..50666215c6 100644
--- a/qmake/generators/win32/msvc_nmake.cpp
+++ b/qmake/generators/win32/msvc_nmake.cpp
@@ -338,8 +338,7 @@ void NmakeMakefileGenerator::writeImplicitRulesPart(QTextStream &t)
         for (const QString &sourceDir : qAsConst(fixifiedSourceDirs)) {
             QDirIterator dit(sourceDir, sourceFilesFilter, QDir::Files | QDir::NoDotAndDotDot);
             while (dit.hasNext()) {
-                dit.next();
-                const QFileInfo fi = dit.fileInfo();
+                const QFileInfo fi = dit.nextFileInfo();
                 QString &duplicate = fileNames[fi.completeBaseName()];
                 if (duplicate.isNull()) {
                     duplicate = fi.filePath();
diff --git a/qmake/main.cpp b/qmake/main.cpp
index d435ecaed8..e99b33bd21 100644
--- a/qmake/main.cpp
+++ b/qmake/main.cpp
@@ -341,8 +341,7 @@ static int installFileOrDirectory(const QString &source, const QString &target,
 
         QDirIterator it(source, QDir::AllEntries | QDir::NoDotAndDotDot | QDir::Hidden);
         while (it.hasNext()) {
-            it.next();
-            const QFileInfo &entry = it.fileInfo();
+            const QFileInfo entry = it.nextFileInfo();
             const QString &entryTarget = target + QDir::separator() + entry.fileName();
 
             const int recursionResult = installFileOrDirectory(entry.filePath(), entryTarget, true);
diff --git a/src/corelib/io/qdir.cpp b/src/corelib/io/qdir.cpp
index e92d2f9ca7..76336ef384 100644
--- a/src/corelib/io/qdir.cpp
+++ b/src/corelib/io/qdir.cpp
@@ -355,10 +355,8 @@ inline void QDirPrivate::initFileLists(const QDir &dir) const
     if (!fileListsInitialized) {
         QFileInfoList l;
         QDirIterator it(dir);
-        while (it.hasNext()) {
-            it.next();
-            l.append(it.fileInfo());
-        }
+        while (it.hasNext())
+            l.append(it.nextFileInfo());
         sortFileList(sort, l, &files, &fileInfos);
         fileListsInitialized = true;
     }
@@ -1397,10 +1395,8 @@ QStringList QDir::entryList(const QStringList &nameFilters, Filters filters,
 
     QFileInfoList l;
     QDirIterator it(d->dirEntry.filePath(), nameFilters, filters);
-    while (it.hasNext()) {
-        it.next();
-        l.append(it.fileInfo());
-    }
+    while (it.hasNext())
+        l.append(it.nextFileInfo());
     QStringList ret;
     d->sortFileList(sort, l, &ret, nullptr);
     return ret;
@@ -1439,10 +1435,8 @@ QFileInfoList QDir::entryInfoList(const QStringList &nameFilters, Filters filter
 
     QFileInfoList l;
     QDirIterator it(d->dirEntry.filePath(), nameFilters, filters);
-    while (it.hasNext()) {
-        it.next();
-        l.append(it.fileInfo());
-    }
+    while (it.hasNext())
+        l.append(it.nextFileInfo());
     QFileInfoList ret;
     d->sortFileList(sort, l, nullptr, &ret);
     return ret;
@@ -1580,8 +1574,7 @@ bool QDir::removeRecursively()
     // not empty -- we must empty it first
     QDirIterator di(dirPath, QDir::AllEntries | QDir::Hidden | QDir::System | QDir::NoDotAndDotDot);
     while (di.hasNext()) {
-        di.next();
-        const QFileInfo& fi = di.fileInfo();
+        const QFileInfo fi = di.nextFileInfo();
         const QString &filePath = di.filePath();
         bool ok;
         if (fi.isDir() && !fi.isSymLink()) {
diff --git a/src/corelib/io/qdiriterator.cpp b/src/corelib/io/qdiriterator.cpp
index 792f2a863d..7e86aacdb1 100644
--- a/src/corelib/io/qdiriterator.cpp
+++ b/src/corelib/io/qdiriterator.cpp
@@ -60,11 +60,11 @@
 
     \snippet code/src_corelib_io_qdiriterator.cpp 1
 
-    The next() function returns the path to the next directory entry and
-    advances the iterator. You can also call filePath() to get the current
-    file path without advancing the iterator.  The fileName() function returns
-    only the name of the file, similar to how QDir::entryList() works. You can
-    also call fileInfo() to get a QFileInfo for the current entry.
+    The next() and nextFileInfo() functions advance the iterator and return
+    the path or the QFileInfo of the next directory entry. You can also call
+    filePath() or fileInfo() to get the current file path or QFileInfo without
+    first advancing the iterator. The fileName() function returns only the
+    name of the file, similar to how QDir::entryList() works.
 
     Unlike Qt's container iterators, QDirIterator is uni-directional (i.e.,
     you cannot iterate directories in reverse order) and does not allow random
@@ -490,10 +490,12 @@ QDirIterator::~QDirIterator()
     new entry. If hasNext() returns \c false, this function does nothing, and
     returns an empty QString.
 
-    You can call fileName() or filePath() to get the current entry file name
+    You can call fileName() or filePath() to get the current entry's file name
     or path, or fileInfo() to get a QFileInfo for the current entry.
 
-    \sa hasNext(), fileName(), filePath(), fileInfo()
+    Call nextFileInfo() instead of next() if you're interested in the QFileInfo.
+
+    \sa hasNext(), nextFileInfo(), fileName(), filePath(), fileInfo()
 */
 QString QDirIterator::next()
 {
@@ -502,10 +504,30 @@ QString QDirIterator::next()
 }
 
 /*!
+    \since 6.3
+
+    Advances the iterator to the next entry, and returns the file info of this
+    new entry. If hasNext() returns \c false, this function does nothing, and
+    returns an empty QFileInfo.
+
+    You can call fileName() or filePath() to get the current entry's file name
+    or path, or fileInfo() to get a QFileInfo for the current entry.
+
+    Call next() instead of nextFileInfo() when all you need is the filePath().
+
+    \sa hasNext(), fileName(), filePath(), fileInfo()
+*/
+QFileInfo QDirIterator::nextFileInfo()
+{
+    d->advance();
+    return fileInfo();
+}
+
+/*!
     Returns \c true if there is at least one more entry in the directory;
     otherwise, false is returned.
 
-    \sa next(), fileName(), filePath(), fileInfo()
+    \sa next(), nextFileInfo(), fileName(), filePath(), fileInfo()
 */
 bool QDirIterator::hasNext() const
 {
diff --git a/src/corelib/io/qdiriterator.h b/src/corelib/io/qdiriterator.h
index acfe040a26..f3a4b979ac 100644
--- a/src/corelib/io/qdiriterator.h
+++ b/src/corelib/io/qdiriterator.h
@@ -69,6 +69,7 @@ public:
     ~QDirIterator();
 
     QString next();
+    QFileInfo nextFileInfo();
     bool hasNext() const;
 
     QString fileName() const;
diff --git a/src/corelib/io/qfileinfo.cpp b/src/corelib/io/qfileinfo.cpp
index 8d471c3e1c..8f2eecc22a 100644
--- a/src/corelib/io/qfileinfo.cpp
+++ b/src/corelib/io/qfileinfo.cpp
@@ -1694,10 +1694,8 @@ QDebug operator<<(QDebug dbg, const QFileInfo &fi)
 
     QDirIterator it(dir);
     while (it.hasNext()) {
-        it.next();
-
         // Extract the QFileInfo from the iterator directly:
-        QFileInfo fi = it.fileInfo();
+        QFileInfo fi = it.nextFileInfo();
 
         ~~~
     }
diff --git a/src/corelib/io/qstorageinfo_unix.cpp b/src/corelib/io/qstorageinfo_unix.cpp
index bdb798e89a..6845a24838 100644
--- a/src/corelib/io/qstorageinfo_unix.cpp
+++ b/src/corelib/io/qstorageinfo_unix.cpp
@@ -793,8 +793,7 @@ static inline QString retrieveLabel(const QByteArray &device)
 
     QDirIterator it(QLatin1String(pathDiskByLabel), QDir::NoDotAndDotDot);
     while (it.hasNext()) {
-        it.next();
-        QFileInfo fileInfo(it.fileInfo());
+        QFileInfo fileInfo = it.nextFileInfo();
         if (fileInfo.isSymLink() && fileInfo.symLinkTarget() == devicePath)
             return decodeFsEncString(fileInfo.fileName());
     }
diff --git a/src/gui/itemmodels/qfileinfogatherer.cpp b/src/gui/itemmodels/qfileinfogatherer.cpp
index bd368e945c..ec4ae2269b 100644
--- a/src/gui/itemmodels/qfileinfogatherer.cpp
+++ b/src/gui/itemmodels/qfileinfogatherer.cpp
@@ -401,8 +401,7 @@ void QFileInfoGatherer::getFileInfos(const QString &path, const QStringList &fil
     if (files.isEmpty()) {
         QDirIterator dirIt(path, QDir::AllEntries | QDir::System | QDir::Hidden);
         while (!abort.loadRelaxed() && dirIt.hasNext()) {
-            dirIt.next();
-            fileInfo = dirIt.fileInfo();
+            fileInfo = dirIt.nextFileInfo();
             fileInfo.stat();
             allFiles.append(fileInfo.fileName());
             fetch(fileInfo, base, firstTime, updatedFiles, path);
diff --git a/src/network/access/qnetworkdiskcache.cpp b/src/network/access/qnetworkdiskcache.cpp
index 7b17540417..c6c20b742c 100644
--- a/src/network/access/qnetworkdiskcache.cpp
+++ b/src/network/access/qnetworkdiskcache.cpp
@@ -522,8 +522,8 @@ qint64 QNetworkDiskCache::expire()
     QMultiMap<QDateTime, QString> cacheItems;
     qint64 totalSize = 0;
     while (it.hasNext()) {
-        QString path = it.next();
-        QFileInfo info = it.fileInfo();
+        QFileInfo info = it.nextFileInfo();
+        QString path = info.filePath();
         QString fileName = info.fileName();
         if (fileName.endsWith(CACHE_POSTFIX)) {
             const QDateTime birthTime = info.fileTime(QFile::FileBirthTime);
diff --git a/src/plugins/tls/openssl/qtlsbackend_openssl.cpp b/src/plugins/tls/openssl/qtlsbackend_openssl.cpp
index 2374f79ed6..5d3b3ea582 100644
--- a/src/plugins/tls/openssl/qtlsbackend_openssl.cpp
+++ b/src/plugins/tls/openssl/qtlsbackend_openssl.cpp
@@ -413,9 +413,8 @@ QList<QSslCertificate> systemCaCertificates()
             currentDir.setPath(QLatin1String(directory));
             QDirIterator it(currentDir);
             while (it.hasNext()) {
-                it.next();
                 // use canonical path here to not load the same certificate twice if symlinked
-                certFiles.insert(it.fileInfo().canonicalFilePath());
+                certFiles.insert(it.nextFileInfo().canonicalFilePath());
             }
         }
         for (const QString& file : qAsConst(certFiles))
diff --git a/src/testlib/qtestcase.cpp b/src/testlib/qtestcase.cpp
index 8d43815cc8..631ca9afb6 100644
--- a/src/testlib/qtestcase.cpp
+++ b/src/testlib/qtestcase.cpp
@@ -2158,9 +2158,7 @@ QSharedPointer<QTemporaryDir> QTest::qExtractTestData(const QString &dirName)
       }
 
       while (it.hasNext()) {
-          it.next();
-
-          QFileInfo fileInfo = it.fileInfo();
+          QFileInfo fileInfo = it.nextFileInfo();
 
           if (!fileInfo.isDir()) {
               const QString destination = dataPath + QLatin1Char('/') + QStringView{fileInfo.filePath()}.mid(resourcePath.length());
diff --git a/src/tools/androiddeployqt/main.cpp b/src/tools/androiddeployqt/main.cpp
index 0bd9f4e16e..25e5ea3d44 100644
--- a/src/tools/androiddeployqt/main.cpp
+++ b/src/tools/androiddeployqt/main.cpp
@@ -1080,8 +1080,7 @@ bool readInputFile(Options *options)
                 if (QFileInfo(path).isDir()) {
                     QDirIterator iterator(path, QDirIterator::Subdirectories);
                     while (iterator.hasNext()) {
-                        iterator.next();
-                        if (iterator.fileInfo().isFile()) {
+                        if (iterator.nextFileInfo().isFile()) {
                             QString subPath = iterator.filePath();
                             auto arch = fileArchitecture(*options, subPath);
                             if (!arch.isEmpty()) {
diff --git a/tests/auto/corelib/io/qdir/tst_qdir.cpp b/tests/auto/corelib/io/qdir/tst_qdir.cpp
index a132750113..7b7a996cdd 100644
--- a/tests/auto/corelib/io/qdir/tst_qdir.cpp
+++ b/tests/auto/corelib/io/qdir/tst_qdir.cpp
@@ -242,9 +242,7 @@ tst_QDir::tst_QDir()
     QString resourceSourcePath = QStringLiteral(":/android_testdata/");
     QDirIterator it(resourceSourcePath, QDirIterator::Subdirectories);
     while (it.hasNext()) {
-        it.next();
-
-        QFileInfo fileInfo = it.fileInfo();
+        QFileInfo fileInfo = it.nextFileInfo();
 
         if (!fileInfo.isDir()) {
             QString destination = m_dataPath + QLatin1Char('/') + fileInfo.filePath().mid(resourceSourcePath.length());
diff --git a/tests/auto/corelib/io/qdiriterator/tst_qdiriterator.cpp b/tests/auto/corelib/io/qdiriterator/tst_qdiriterator.cpp
index b41352185d..35282ccaa3 100644
--- a/tests/auto/corelib/io/qdiriterator/tst_qdiriterator.cpp
+++ b/tests/auto/corelib/io/qdiriterator/tst_qdiriterator.cpp
@@ -127,9 +127,7 @@ void tst_QDirIterator::initTestCase()
     QString resourceSourcePath = QStringLiteral(":/testdata");
     QDirIterator it(resourceSourcePath, QDirIterator::Subdirectories);
     while (it.hasNext()) {
-        it.next();
-
-        QFileInfo fileInfo = it.fileInfo();
+        QFileInfo fileInfo = it.nextFileInfo();
 
         if (!fileInfo.isDir()) {
             QString destination = testdata_dir + QLatin1Char('/') + fileInfo.filePath().mid(resourceSourcePath.length());
@@ -467,7 +465,7 @@ void tst_QDirIterator::stopLinkLoop()
     QStringList list;
     int max = 200;
     while (--max && it.hasNext())
-        it.next();
+        it.nextFileInfo();
     QVERIFY(max);
 
     // The goal of this test is only to ensure that the test above don't malfunction
@@ -508,10 +506,8 @@ void tst_QDirIterator::engineWithNoIterator()
 void tst_QDirIterator::absoluteFilePathsFromRelativeIteratorPath()
 {
     QDirIterator it("entrylist/", QDir::NoDotAndDotDot);
-    while (it.hasNext()) {
-        it.next();
-        QVERIFY(QFileInfo(it.filePath()).absoluteFilePath().contains("entrylist"));
-    }
+    while (it.hasNext())
+        QVERIFY(it.nextFileInfo().absoluteFilePath().contains("entrylist"));
 }
 
 void tst_QDirIterator::recurseWithFilters() const
@@ -528,11 +524,9 @@ void tst_QDirIterator::recurseWithFilters() const
     expectedEntries.insert(QString::fromLatin1("recursiveDirs/textFileA.txt"));
 
     QVERIFY(it.hasNext());
-    it.next();
-    actualEntries.insert(it.fileInfo().filePath());
+    actualEntries.insert(it.next());
     QVERIFY(it.hasNext());
-    it.next();
-    actualEntries.insert(it.fileInfo().filePath());
+    actualEntries.insert(it.next());
     QCOMPARE(actualEntries, expectedEntries);
 
     QVERIFY(!it.hasNext());
@@ -555,7 +549,7 @@ void tst_QDirIterator::longPath()
     int m = 0;
     while (it.hasNext()) {
         ++m;
-        it.next();
+        it.nextFileInfo();
     }
 
     QCOMPARE(n, m);
@@ -622,8 +616,7 @@ void tst_QDirIterator::hiddenDirs_hiddenFiles()
         QDirIterator di("hiddenDirs_hiddenFiles", QDir::Files | QDir::Hidden | QDir::NoDotAndDotDot, QDirIterator::Subdirectories);
         while (di.hasNext()) {
             ++matches;
-            QString filename = di.next();
-            if (QFileInfo(filename).isDir())
+            if (di.nextFileInfo().isDir())
                 ++failures;    // search was only supposed to find files
         }
         QCOMPARE(matches, 6);
@@ -636,8 +629,7 @@ void tst_QDirIterator::hiddenDirs_hiddenFiles()
         QDirIterator di("hiddenDirs_hiddenFiles", QDir::Dirs | QDir::Hidden | QDir::NoDotAndDotDot, QDirIterator::Subdirectories);
         while (di.hasNext()) {
             ++matches;
-            QString filename = di.next();
-            if (!QFileInfo(filename).isDir())
+            if (!di.nextFileInfo().isDir())
                 ++failures;    // search was only supposed to find files
         }
         QCOMPARE(matches, 6);
diff --git a/tests/auto/corelib/io/qresourceengine/tst_qresourceengine.cpp b/tests/auto/corelib/io/qresourceengine/tst_qresourceengine.cpp
index b2f7aedab0..317a57a44c 100644
--- a/tests/auto/corelib/io/qresourceengine/tst_qresourceengine.cpp
+++ b/tests/auto/corelib/io/qresourceengine/tst_qresourceengine.cpp
@@ -77,9 +77,7 @@ void tst_QResourceEngine::initTestCase()
 
     QDirIterator it(sourcePath, QDirIterator::Subdirectories);
     while (it.hasNext()) {
-        it.next();
-
-        QFileInfo fileInfo = it.fileInfo();
+        QFileInfo fileInfo = it.nextFileInfo();
         if (!fileInfo.isDir()) {
             QString destination(dataPath + QLatin1Char('/') + fileInfo.filePath().mid(sourcePath.length()));
             QFileInfo destinationFileInfo(destination);
diff --git a/tests/auto/corelib/io/qtemporaryfile/tst_qtemporaryfile.cpp b/tests/auto/corelib/io/qtemporaryfile/tst_qtemporaryfile.cpp
index 5c7d69a788..dcf3486449 100644
--- a/tests/auto/corelib/io/qtemporaryfile/tst_qtemporaryfile.cpp
+++ b/tests/auto/corelib/io/qtemporaryfile/tst_qtemporaryfile.cpp
@@ -111,9 +111,7 @@ void tst_QTemporaryFile::initTestCase()
     QString sourceDir(":/android_testdata/");
     QDirIterator it(sourceDir, QDirIterator::Subdirectories);
     while (it.hasNext()) {
-        it.next();
-
-        QFileInfo sourceFileInfo = it.fileInfo();
+        QFileInfo sourceFileInfo = it.nextFileInfo();
         if (!sourceFileInfo.isDir()) {
             QFileInfo destinationFileInfo(QStandardPaths::writableLocation(QStandardPaths::CacheLocation) + QLatin1Char('/') + sourceFileInfo.filePath().mid(sourceDir.length()));
 
diff --git a/tests/auto/tools/rcc/tst_rcc.cpp b/tests/auto/tools/rcc/tst_rcc.cpp
index 9b04987168..359ee7021e 100644
--- a/tests/auto/tools/rcc/tst_rcc.cpp
+++ b/tests/auto/tools/rcc/tst_rcc.cpp
@@ -274,8 +274,7 @@ void tst_rcc::binary_data()
     QDirIterator iter(dataPath, QStringList() << QLatin1String("*.qrc"));
     while (iter.hasNext())
     {
-        iter.next();
-        QFileInfo qrcFileInfo = iter.fileInfo();
+        QFileInfo qrcFileInfo = iter.nextFileInfo();
         QString absoluteBaseName = QFileInfo(qrcFileInfo.absolutePath(), qrcFileInfo.baseName()).absoluteFilePath();
         QString rccFileName = absoluteBaseName + QLatin1String(".rcc");
 
diff --git a/tests/benchmarks/corelib/io/qdir/10000/bench_qdir_10000.cpp b/tests/benchmarks/corelib/io/qdir/10000/bench_qdir_10000.cpp
index 3184df0d7b..e02cfb3099 100644
--- a/tests/benchmarks/corelib/io/qdir/10000/bench_qdir_10000.cpp
+++ b/tests/benchmarks/corelib/io/qdir/10000/bench_qdir_10000.cpp
@@ -83,9 +83,9 @@ private slots:
         QBENCHMARK {
             QDirIterator dit(testdir.path(), QDir::Files);
             while (dit.hasNext()) {
-                dit.next();
-                dit.fileInfo().isDir();
-                dit.fileInfo().size();
+                const auto fi = dit.nextFileInfo();
+                (void)fi.isDir();
+                (void)fi.size();
             }
         }
     }
@@ -104,9 +104,9 @@ private slots:
         QBENCHMARK {
             QDirIterator dit(testdir.path());
             while (dit.hasNext()) {
-                dit.next();
-                dit.fileInfo().isDir();
-                dit.fileInfo().size();
+                const auto fi = dit.nextFileInfo();
+                (void)fi.isDir();
+                (void)fi.size();
             }
         }
     }
diff --git a/tests/benchmarks/corelib/io/qdir/tree/bench_qdir_tree.cpp b/tests/benchmarks/corelib/io/qdir/tree/bench_qdir_tree.cpp
index 0abf8769a6..3a7db36ea2 100644
--- a/tests/benchmarks/corelib/io/qdir/tree/bench_qdir_tree.cpp
+++ b/tests/benchmarks/corelib/io/qdir/tree/bench_qdir_tree.cpp
@@ -211,9 +211,8 @@ private slots:
             int count = 0;
             QDirIterator iter(dirName, QDir::Files, QDirIterator::Subdirectories);
             while(iter.hasNext()) {
-                iter.next();
                 count++;
-                totalsize += iter.fileInfo().size();
+                totalsize += iter.nextFileInfo().size();
             }
             QCOMPARE(count, 1000);
             QCOMPARE(totalsize, expectedSize);
diff --git a/tests/benchmarks/corelib/io/qdiriterator/main.cpp b/tests/benchmarks/corelib/io/qdiriterator/main.cpp
index 8c180f8757..acf1ede368 100644
--- a/tests/benchmarks/corelib/io/qdiriterator/main.cpp
+++ b/tests/benchmarks/corelib/io/qdiriterator/main.cpp
@@ -189,13 +189,13 @@ void tst_qdiriterator::diriterator()
             QDirIterator::Subdirectories);
 
         while (dir.hasNext()) {
-            dir.next();
+            const auto fi = dir.nextFileInfo();
             //printf("%s\n", qPrintable(dir.fileName()));
             0 && printf("%d %s\n",
-                dir.fileInfo().isDir(),
-                //qPrintable(dir.fileInfo().absoluteFilePath()),
+                fi.isDir(),
+                //qPrintable(fi.absoluteFilePath()),
                 //qPrintable(dir.path()),
-                qPrintable(dir.filePath()));
+                qPrintable(fi.filePath()));
             ++c;
         }
         count = c;