QMimeDatabase: follow symlinks when checking for FIFO etc.

This was documented, but not what the code did.

Task-number: QTBUG-48529
Change-Id: I4849778c61dcae13be27c62b24717693c0c07d78
Reviewed-by: Edward Welbourne <edward.welbourne@theqtcompany.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/mimetypes/qmimedatabase.cpp

@@ -354,9 +354,10 @@ QMimeType QMimeDatabase::mimeTypeForFile(const QFileInfo &fileInfo, MatchMode mo
 
 #ifdef Q_OS_UNIX
     // Cannot access statBuf.st_mode from the filesystem engine, so we have to stat again.
+    // In addition we want to follow symlinks.
     const QByteArray nativeFilePath = QFile::encodeName(file.fileName());
     QT_STATBUF statBuffer;
-    if (QT_LSTAT(nativeFilePath.constData(), &statBuffer) == 0) {
+    if (QT_STAT(nativeFilePath.constData(), &statBuffer) == 0) {
         if (S_ISCHR(statBuffer.st_mode))
             return d->mimeTypeForName(QLatin1String("inode/chardevice"));
         if (S_ISBLK(statBuffer.st_mode))

tests/auto/corelib/mimetypes/qmimedatabase/tst_qmimedatabase.cpp

@@ -35,6 +35,11 @@
 
 #include "qstandardpaths.h"
 
+#ifdef Q_OS_UNIX
+#include <sys/types.h>
+#include <sys/stat.h>
+#endif
+
 #include <QtCore/QElapsedTimer>
 #include <QtCore/QFile>
 #include <QtCore/QFileInfo>
@@ -646,6 +651,28 @@ void tst_QMimeDatabase::knownSuffix()
     QCOMPARE(db.suffixForFileName(QString::fromLatin1("foo.tar.bz2")), QString::fromLatin1("tar.bz2"));
 }
 
+void tst_QMimeDatabase::symlinkToFifo() // QTBUG-48529
+{
+#ifdef Q_OS_UNIX
+    QTemporaryDir tempDir;
+    QVERIFY(tempDir.isValid());
+    const QString dir = tempDir.path();
+    const QString fifo = dir + "/fifo";
+    QCOMPARE(mkfifo(QFile::encodeName(fifo), 0006), 0);
+
+    QMimeDatabase db;
+    QCOMPARE(db.mimeTypeForFile(fifo).name(), QString::fromLatin1("inode/fifo"));
+
+    // Now make a symlink to the fifo
+    const QString link = dir + "/link";
+    QVERIFY(QFile::link(fifo, link));
+    QCOMPARE(db.mimeTypeForFile(link).name(), QString::fromLatin1("inode/fifo"));
+
+#else
+    QSKIP("This test requires pipes and symlinks");
+#endif
+}
+
 void tst_QMimeDatabase::findByFileName_data()
 {
     QTest::addColumn<QString>("filePath");

tests/auto/corelib/mimetypes/qmimedatabase/tst_qmimedatabase.h

@@ -70,6 +70,7 @@ private slots:
     void suffixes_data();
     void suffixes();
     void knownSuffix();
+    void symlinkToFifo();
     void fromThreads();
 
     // shared-mime-info test suite