commit 4d0569da8d362b6869158beb724319023e4c705a
Author: Dawit Alemayehu <adawit@kde.org>
Date:   Fri Feb 4 18:29:51 2011 -0500

    Workaround for the hang (freeze) when opening VLC's file dialog under KDE.
    See http://git.reviewboard.kde.org/r/100539/ for the details.
    
    BUG:260719
    REVIEW:100539
    (cherry picked from commit 7ca7e81303c50769e286897be0afe0793dabdf52)

diff --git a/kdecore/services/kmimetyperepository.cpp b/kdecore/services/kmimetyperepository.cpp
index 9f4c3ca..39e6a61 100644
--- a/kdecore/services/kmimetyperepository.cpp
+++ b/kdecore/services/kmimetyperepository.cpp
@@ -683,29 +683,84 @@ bool KMimeTypeRepository::useFavIcons()
     return m_useFavIcons;
 }
 
-int KMimeTypeRepository::sharedMimeInfoVersion()
+static void addPlatformSpecificPkgConfigPath(QStringList& paths)
 {
-    m_mutex.lockForWrite();
-    if (m_sharedMimeInfoVersion == 0) {
-        QProcess smi;
-        const QString umd = KStandardDirs::findExe(QString::fromLatin1("update-mime-database"));
-        if (umd.isEmpty()) {
-            kWarning() << "update-mime-database not found!";
-            m_sharedMimeInfoVersion = -1;
-        } else {
-            smi.start(umd, QStringList() << QString::fromLatin1("-v"));
-            smi.waitForStarted();
-            smi.waitForFinished();
-            const QString out = QString::fromLocal8Bit(smi.readAllStandardError());
-            QRegExp versionRe(QString::fromLatin1("update-mime-database \\(shared-mime-info\\) (\\d+)\\.(\\d+)(\\.(\\d+))?"));
-            if (versionRe.indexIn(out) > -1) {
-                m_sharedMimeInfoVersion = KDE_MAKE_VERSION(versionRe.cap(1).toInt(), versionRe.cap(2).toInt(), versionRe.cap(4).toInt());
-            } else {
-                kWarning() << "Unexpected version scheme from update-mime-database -v: got" << out;
-                m_sharedMimeInfoVersion = -1;
+#if defined (Q_OS_FREEBSD)
+    paths << QLatin1String("/usr/local/libdata/pkgconfig"); // FreeBSD
+#elif defined(Q_OS_OPENBSD) || defined(Q_OS_NETBSD) || defined(Q_OS_SOLARIS)
+    paths << QLatin1String("/usr/local/lib/pkgconfig"); // {Net,Open}BSD/OpenSolaris
+#elif defined (Q_OS_UNIX)
+    paths << QLatin1String("/usr/share/pkgconfig"); // Linux and all other unix
+#endif
+}
+
+static int mimeDataBaseVersion()
+{
+    // TODO: Remove the #idef'ed code below once the issue is fixed either
+    // in QProcess or the shared-mime-info utility provides its version number.
+#ifdef Q_OS_UNIX
+    // Try to read the version number from the shared-mime-info.pc file
+    QStringList paths;
+    const QByteArray pkgConfigPath = qgetenv("PKG_CONFIG_PATH");
+    if (!pkgConfigPath.isEmpty()) {
+        paths << QFile::decodeName(pkgConfigPath).split(QLatin1Char(':'), QString::SkipEmptyParts);
+    }
+
+    // Add platform specific hard-coded default paths to the list...
+    addPlatformSpecificPkgConfigPath(paths);
+
+    Q_FOREACH(const QString& path, paths) {
+        const QString fileName = path + QLatin1String("/shared-mime-info.pc");
+        if (!QFile::exists(fileName)) {
+            continue;
+        }
+
+        QFile file (fileName);
+        if (!file.open(QIODevice::ReadOnly)) {
+            break;
+        }
+
+        while (!file.atEnd()) {
+            const QByteArray line = file.readLine().simplified();
+            if (!line.startsWith("Version")) {
+                continue;
+            }
+            QRegExp versionRe(QString::fromLatin1("Version: (\\d+)\\.(\\d+)(\\.(\\d+))?"));
+            if (versionRe.indexIn(QString::fromLocal8Bit(line)) > -1) {
+                return KDE_MAKE_VERSION(versionRe.cap(1).toInt(), versionRe.cap(2).toInt(), versionRe.cap(4).toInt());
             }
         }
     }
+#endif
+
+    // Execute "update-mime-database -v" to determine version number.
+    // NOTE: On *nix, the code below is known to cause freezes/hangs in apps
+    // that block signals. See https://bugs.kde.org/show_bug.cgi?id=260719.
+    const QString umd = KStandardDirs::findExe(QString::fromLatin1("update-mime-database"));
+    if (umd.isEmpty()) {
+        kWarning(servicesDebugArea()) << "update-mime-database not found!";
+        return -1;
+    }
+
+    QProcess smi;
+    smi.start(umd, QStringList() << QString::fromLatin1("-v"));
+    smi.waitForStarted();
+    smi.waitForFinished();
+    const QString out = QString::fromLocal8Bit(smi.readAllStandardError());
+    QRegExp versionRe(QString::fromLatin1("update-mime-database \\(shared-mime-info\\) (\\d+)\\.(\\d+)(\\.(\\d+))?"));
+    if (versionRe.indexIn(out) > -1) {
+        return KDE_MAKE_VERSION(versionRe.cap(1).toInt(), versionRe.cap(2).toInt(), versionRe.cap(4).toInt());
+    }
+
+    kWarning(servicesDebugArea()) << "Unexpected version scheme from update-mime-database -v: got" << out;
+    return -1;
+}
+
+int KMimeTypeRepository::sharedMimeInfoVersion()
+{
+    m_mutex.lockForWrite();
+    if (m_sharedMimeInfoVersion == 0)
+        m_sharedMimeInfoVersion = mimeDataBaseVersion();
     m_mutex.unlock();
     return m_sharedMimeInfoVersion;
 }