filter KIO: add zstd support

doc/kioslave/CMakeLists.txt

@@ -17,3 +17,6 @@ add_subdirectory(thumbnail)
 if(KArchive_HAVE_LZMA)
   add_subdirectory(xz)
 endif()
+if(KArchive_HAVE_ZSTD)
+  add_subdirectory(zstd)
+endif()

doc/kioslave/zstd/CMakeLists.txt

+########### install files ###############
+kdoctools_create_handbook(index.docbook INSTALL_DESTINATION ${KDE_INSTALL_DOCBUNDLEDIR}/en SUBDIR kioslave5/zstd)

doc/kioslave/zstd/index.docbook

+<?xml version="1.0" ?>
+<!DOCTYPE article PUBLIC "-//KDE//DTD DocBook XML V4.5-Based Variant V1.1//EN"
+"dtd/kdedbx45.dtd" [
+<!ENTITY % addindex "IGNORE">
+<!ENTITY % English "INCLUDE" > <!-- change language only here -->
+]>
+	
+<article lang="&language;" id="zstd">
+<title>zstd</title>
+<articleinfo>
+<authorgroup>
+<author><firstname>Friedrich</firstname><othername>W. H.</othername><surname>Kossebau</surname></author>
+<!-- TRANS:ROLES_OF_TRANSLATORS -->
+</authorgroup>
+</articleinfo>
+
+<para><command>zstd</command> is a compression program.</para>
+
+<para>The zstd kioslave is not directly usable, and is intended for use
+as a filter.  For example, the tar kioslave can filter a file through
+the zstd kioslave, in order to display the contents of a <literal
+role="extension">tar.zst</literal> file directly in a &konqueror;
+window.</para>
+
+<para>If you click on a file compressed with a <literal
+role="extension">zst</literal> extension in &konqueror;, this kioslave is
+used to uncompress it and display it as a normal (uncompressed)
+file.</para>
+
+<para>If you are a developer, and would like to use the zstd filter, you
+can find documentation on using kioslaves at <ulink
+url="http://techbase.kde.org">http://techbase.kde.org</ulink></para>
+
+<para> See the manual: <ulink url="man:/zstd">zstd</ulink>.
+</para>
+
+</article>

filter/filter.cpp

@@ -61,7 +61,10 @@ int kdemain( int argc, char ** argv)
 FilterProtocol::FilterProtocol( const QByteArray & protocol, const QByteArray &pool, const QByteArray &app )
     : KIO::SlaveBase( protocol, pool, app )
 {
-    QString mimetype = QString::fromLatin1("application/x-") + QString::fromLatin1(protocol);
+    const QString mimetype =
+        (protocol == "zstd") ? QStringLiteral("application/zstd") :
+        QLatin1String("application/x-") + QLatin1String(protocol.constData());
+
 #if KARCHIVE_VERSION >= QT_VERSION_CHECK(5, 85, 0)
     filter = KCompressionDevice::filterForCompressionType(KCompressionDevice::compressionTypeForMimeType( mimetype ));
 #else
@@ -140,7 +143,7 @@ void FilterProtocol::get(const QUrl& url)
                 const QString extension = QFileInfo(subURL.path()).suffix();
                 QMimeDatabase db;
                 QMimeType mime;
-                if (extension == "gz" || extension == "bz" || extension == "bz2") {
+                if (extension == "gz" || extension == "bz" || extension == "bz2"|| extension == "zst") {
                     QString baseName = subURL.path();
                     baseName.truncate(baseName.length() - extension.length() - 1 /*the dot*/);
                     qDebug(KIO_FILTER_DEBUG) << "baseName=" << baseName;

filter/filter.json

@@ -69,6 +69,20 @@
             "protocol": "xz",
             "reading": true,
             "source": false
+        },
+        "zstd": {
+            "Icon": "package-x-generic",
+            "X-DocPath": "kioslave5/zstd/index.html",
+            "archiveMimetype": [
+                "application/zstd"
+            ],
+            "determineMimetypeFromExtension": true,
+            "exec": "kf5/kio/filter",
+            "input": "stream",
+            "output": "stream",
+            "protocol": "zstd",
+            "reading": true,
+            "source": false
         }
     }
 }