[libcalamares] Add partition service for managing global storage

- the global storage key filesystem_use has a structured meaning,
  so give it a (trivial-ish) API for reading and writing.

src/libcalamares/CMakeLists.txt

@@ -63,6 +63,7 @@ set( libSources
     packages/Globals.cpp
 
     # Partition service
+    partition/Global.cpp
     partition/Mount.cpp
     partition/PartitionSize.cpp
     partition/Sync.cpp

src/libcalamares/partition/Global.cpp

@@ -0,0 +1,78 @@
+/* === This file is part of Calamares - <https://calamares.io> ===
+ *
+ *   SPDX-FileCopyrightText: 2021 Adriaan de Groot <groot@kde.org>
+ *   SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *   Calamares is Free Software: see the License-Identifier above.
+ *
+ *
+ */
+#include "Global.h"
+
+#include "FileSystem.h"
+#include "GlobalStorage.h"
+#include "JobQueue.h"
+
+#include <QVariantMap>
+
+static const QString fsUse_key = QStringLiteral( "filesystem_use" );
+
+STATICTEST
+bool
+isFilesystemUsedGS( const Calamares::GlobalStorage& gs, const QString& filesystemType )
+{
+
+    const QVariantMap fsUse = gs.value( fsUse_key ).toMap();
+    if ( fsUse.contains( filesystemType ) )
+    {
+        const auto v = fsUse.value( filesystemType );
+        return v.toBool();
+    }
+    return false;
+}
+
+STATICTEST void
+useFilesystemGS( Calamares::GlobalStorage& gs, const QString& filesystemType, bool used )
+{
+    QVariantMap existingMap = gs.contains( fsUse_key ) ? gs.value( fsUse_key ).toMap() : QVariantMap();
+    existingMap.insert( filesystemType, used );
+    gs.insert( fsUse_key, existingMap );
+}
+
+bool
+CalamaresUtils::Partition::isFilesystemUsedGS( const QString& filesystemType )
+{
+    const auto* jq = Calamares::JobQueue::instance();
+    const auto* gs = jq ? jq->globalStorage() : nullptr;
+
+    if ( !gs )
+    {
+        return false;
+    }
+    return isFilesystemUsedGS( *gs, filesystemType );
+}
+
+void
+CalamaresUtils::Partition::useFilesystemGS( const QString& filesystemType, bool used )
+{
+    const auto* jq = Calamares::JobQueue::instance();
+    auto* gs = jq ? jq->globalStorage() : nullptr;
+
+    if ( gs )
+    {
+        useFilesystemGS( *gs, filesystemType, used );
+    }
+}
+
+#ifdef WITH_KPMCORE4API
+bool
+CalamaresUtils::Partition::isFilesystemUsedGS( FileSystem::Type filesystem )
+{
+    return isFilesystemUsedGS( untranslatedFS( filesystem ) );
+}
+void
+CalamaresUtils::Partition::useFilesystemGS( FileSystem::Type filesystem, bool used )
+{
+    useFilesystemGS( untranslatedFS( filesystem ), used );
+}
+#endif

src/libcalamares/partition/Global.h

@@ -0,0 +1,66 @@
+/* === This file is part of Calamares - <https://calamares.io> ===
+ *
+ *   SPDX-FileCopyrightText: 2021 Adriaan de Groot <groot@kde.org>
+ *   SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *   Calamares is Free Software: see the License-Identifier above.
+ *
+ *
+ */
+
+/*
+ * This is the API for manipulating Global Storage keys related to
+ * filesystems and partitions.
+ */
+
+#ifndef PARTITION_GLOBAL_H
+#define PARTITION_GLOBAL_H
+
+#include "DllMacro.h"
+
+#ifdef WITH_KPMCORE4API
+#include <kpmcore/fs/filesystem.h>
+#endif
+
+namespace CalamaresUtils
+{
+namespace Partition
+{
+/** @brief Mark a particular filesystem type as used (or not)
+ *
+ * Filesystems are marked used (or not) in the global storage
+ * key *filesystem_use*. Sub-keys are the filesystem name,
+ * and the values are boolean; filesystems that are used in
+ * the target system are marked with @c true. Unused filesystems
+ * may be unmarked, or may be marked @c false.
+ *
+ * The filesystem name should be the untranslated name. Filesystem
+ * names are **lower**cased when used as keys.
+ */
+void DLLEXPORT useFilesystemGS( const QString& filesystemType, bool used );
+/** @brief Reads from global storage whether the filesystem type is used
+ *
+ * Reads from the global storage key *filesystem_use* and returns
+ * the boolean value stored in subkey @p filesystemType. Returns
+ * @c false if the subkey is not set at all.
+ */
+bool DLLEXPORT isFilesystemUsedGS( const QString& filesystemType );
+
+#ifdef WITH_KPMCORE4API
+/** @brief Mark a particular filesystem type as used (or not)
+ *
+ * See useFilesystemGS(const QString&, bool); this method uses the filesystem type
+ * enumeration to pick the name.
+ */
+void DLLEXPORT useFilesystemGS( FileSystem::Type filesystem, bool used );
+/* @brief Reads from global storage whether the typesystem type is used
+ *
+ * See isFilesystemUsedGS(const QString&).
+ */
+bool DLLEXPORT isFilesystemUsedGS( FileSystem::Type filesystem );
+
+#endif
+}  // namespace Partition
+}  // namespace CalamaresUtils
+
+#endif