file_sys: Create ContentProvider interface and default implementations

src/core/file_sys/registered_cache.cpp

@@ -23,19 +23,19 @@ namespace FileSys {
 // The size of blocks to use when vfs raw copying into nand.
 constexpr size_t VFS_RC_LARGE_COPY_BLOCK = 0x400000;
 
-std::string RegisteredCacheEntry::DebugInfo() const {
+std::string ContentProviderEntry::DebugInfo() const {
     return fmt::format("title_id={:016X}, content_type={:02X}", title_id, static_cast<u8>(type));
 }
 
-bool operator<(const RegisteredCacheEntry& lhs, const RegisteredCacheEntry& rhs) {
+bool operator<(const ContentProviderEntry& lhs, const ContentProviderEntry& rhs) {
     return (lhs.title_id < rhs.title_id) || (lhs.title_id == rhs.title_id && lhs.type < rhs.type);
 }
 
-bool operator==(const RegisteredCacheEntry& lhs, const RegisteredCacheEntry& rhs) {
+bool operator==(const ContentProviderEntry& lhs, const ContentProviderEntry& rhs) {
     return std::tie(lhs.title_id, lhs.type) == std::tie(rhs.title_id, rhs.type);
 }
 
-bool operator!=(const RegisteredCacheEntry& lhs, const RegisteredCacheEntry& rhs) {
+bool operator!=(const ContentProviderEntry& lhs, const ContentProviderEntry& rhs) {
     return !operator==(lhs, rhs);
 }
 
@@ -84,7 +84,7 @@ static std::string GetCNMTName(TitleType type, u64 title_id) {
     return fmt::format("{}_{:016x}.cnmt", TITLE_TYPE_NAMES[index], title_id);
 }
 
-static ContentRecordType GetCRTypeFromNCAType(NCAContentType type) {
+ContentRecordType GetCRTypeFromNCAType(NCAContentType type) {
     switch (type) {
     case NCAContentType::Program:
         // TODO(DarkLordZach): Differentiate between Program and Patch
@@ -104,6 +104,28 @@ static ContentRecordType GetCRTypeFromNCAType(NCAContentType type) {
     }
 }
 
+ContentProvider::~ContentProvider() = default;
+
+bool ContentProvider::HasEntry(ContentProviderEntry entry) const {
+    return HasEntry(entry.title_id, entry.type);
+}
+
+VirtualFile ContentProvider::GetEntryUnparsed(ContentProviderEntry entry) const {
+    return GetEntryUnparsed(entry.title_id, entry.type);
+}
+
+VirtualFile ContentProvider::GetEntryRaw(ContentProviderEntry entry) const {
+    return GetEntryRaw(entry.title_id, entry.type);
+}
+
+std::unique_ptr<NCA> ContentProvider::GetEntry(ContentProviderEntry entry) const {
+    return GetEntry(entry.title_id, entry.type);
+}
+
+std::vector<ContentProviderEntry> ContentProvider::ListEntries() const {
+    return ListEntriesFilter(std::nullopt, std::nullopt, std::nullopt);
+}
+
 VirtualFile RegisteredCache::OpenFileOrDirectoryConcat(const VirtualDir& dir,
                                                        std::string_view path) const {
     const auto file = dir->GetFileRelative(path);
@@ -161,8 +183,8 @@ VirtualFile RegisteredCache::GetFileAtID(NcaID id) const {
     return file;
 }
 
-static std::optional<NcaID> CheckMapForContentRecord(
+static std::optional<NcaID> CheckMapForContentRecord(const std::map<u64, CNMT>& map, u64 title_id,
-    const boost::container::flat_map<u64, CNMT>& map, u64 title_id, ContentRecordType type) {
+                                                     ContentRecordType type) {
     if (map.find(title_id) == map.end())
         return {};
 
@@ -268,7 +290,7 @@ void RegisteredCache::Refresh() {
     AccumulateYuzuMeta();
 }
 
-RegisteredCache::RegisteredCache(VirtualDir dir_, RegisteredCacheParsingFunction parsing_function)
+RegisteredCache::RegisteredCache(VirtualDir dir_, ContentProviderParsingFunction parsing_function)
     : dir(std::move(dir_)), parser(std::move(parsing_function)) {
     Refresh();
 }
@@ -279,19 +301,11 @@ bool RegisteredCache::HasEntry(u64 title_id, ContentRecordType type) const {
     return GetEntryRaw(title_id, type) != nullptr;
 }
 
-bool RegisteredCache::HasEntry(RegisteredCacheEntry entry) const {
-    return GetEntryRaw(entry) != nullptr;
-}
-
 VirtualFile RegisteredCache::GetEntryUnparsed(u64 title_id, ContentRecordType type) const {
     const auto id = GetNcaIDFromMetadata(title_id, type);
     return id ? GetFileAtID(*id) : nullptr;
 }
 
-VirtualFile RegisteredCache::GetEntryUnparsed(RegisteredCacheEntry entry) const {
-    return GetEntryUnparsed(entry.title_id, entry.type);
-}
-
 std::optional<u32> RegisteredCache::GetEntryVersion(u64 title_id) const {
     const auto meta_iter = meta.find(title_id);
     if (meta_iter != meta.end())
@@ -309,10 +323,6 @@ VirtualFile RegisteredCache::GetEntryRaw(u64 title_id, ContentRecordType type) c
     return id ? parser(GetFileAtID(*id), *id) : nullptr;
 }
 
-VirtualFile RegisteredCache::GetEntryRaw(RegisteredCacheEntry entry) const {
-    return GetEntryRaw(entry.title_id, entry.type);
-}
-
 std::unique_ptr<NCA> RegisteredCache::GetEntry(u64 title_id, ContentRecordType type) const {
     const auto raw = GetEntryRaw(title_id, type);
     if (raw == nullptr)
@@ -320,10 +330,6 @@ std::unique_ptr<NCA> RegisteredCache::GetEntry(u64 title_id, ContentRecordType t
     return std::make_unique<NCA>(raw, nullptr, 0, keys);
 }
 
-std::unique_ptr<NCA> RegisteredCache::GetEntry(RegisteredCacheEntry entry) const {
-    return GetEntry(entry.title_id, entry.type);
-}
-
 template <typename T>
 void RegisteredCache::IterateAllMetadata(
     std::vector<T>& out, std::function<T(const CNMT&, const ContentRecord&)> proc,
@@ -348,25 +354,14 @@ void RegisteredCache::IterateAllMetadata(
     }
 }
 
-std::vector<RegisteredCacheEntry> RegisteredCache::ListEntries() const {
+std::vector<ContentProviderEntry> RegisteredCache::ListEntriesFilter(
-    std::vector<RegisteredCacheEntry> out;
-    IterateAllMetadata<RegisteredCacheEntry>(
-        out,
-        [](const CNMT& c, const ContentRecord& r) {
-            return RegisteredCacheEntry{c.GetTitleID(), r.type};
-        },
-        [](const CNMT& c, const ContentRecord& r) { return true; });
-    return out;
-}
-
-std::vector<RegisteredCacheEntry> RegisteredCache::ListEntriesFilter(
     std::optional<TitleType> title_type, std::optional<ContentRecordType> record_type,
     std::optional<u64> title_id) const {
-    std::vector<RegisteredCacheEntry> out;
+    std::vector<ContentProviderEntry> out;
-    IterateAllMetadata<RegisteredCacheEntry>(
+    IterateAllMetadata<ContentProviderEntry>(
         out,
         [](const CNMT& c, const ContentRecord& r) {
-            return RegisteredCacheEntry{c.GetTitleID(), r.type};
+            return ContentProviderEntry{c.GetTitleID(), r.type};
         },
         [&title_type, &record_type, &title_id](const CNMT& c, const ContentRecord& r) {
             if (title_type && *title_type != c.GetType())
@@ -521,37 +516,56 @@ bool RegisteredCache::RawInstallYuzuMeta(const CNMT& cnmt) {
                         }) != yuzu_meta.end();
 }
 
-RegisteredCacheUnion::RegisteredCacheUnion(std::vector<RegisteredCache*> caches)
+ContentProviderUnion::~ContentProviderUnion() = default;
-    : caches(std::move(caches)) {}
 
-void RegisteredCacheUnion::Refresh() {
+void ContentProviderUnion::SetSlot(ContentProviderUnionSlot slot, ContentProvider* provider) {
-    for (const auto& c : caches)
+    providers[slot] = provider;
-        c->Refresh();
 }
 
-bool RegisteredCacheUnion::HasEntry(u64 title_id, ContentRecordType type) const {
+void ContentProviderUnion::ClearSlot(ContentProviderUnionSlot slot) {
-    return std::any_of(caches.begin(), caches.end(), [title_id, type](const auto& cache) {
+    providers[slot] = nullptr;
-        return cache->HasEntry(title_id, type);
-    });
 }
 
-bool RegisteredCacheUnion::HasEntry(RegisteredCacheEntry entry) const {
+void ContentProviderUnion::Refresh() {
-    return HasEntry(entry.title_id, entry.type);
+    for (auto& provider : providers) {
+        if (provider.second == nullptr)
+            continue;
+
+        provider.second->Refresh();
+    }
 }
 
-std::optional<u32> RegisteredCacheUnion::GetEntryVersion(u64 title_id) const {
+bool ContentProviderUnion::HasEntry(u64 title_id, ContentRecordType type) const {
-    for (const auto& c : caches) {
+    for (const auto& provider : providers) {
-        const auto res = c->GetEntryVersion(title_id);
+        if (provider.second == nullptr)
-        if (res)
+            continue;
+
+        if (provider.second->HasEntry(title_id, type))
+            return true;
+    }
+
+    return false;
+}
+
+std::optional<u32> ContentProviderUnion::GetEntryVersion(u64 title_id) const {
+    for (const auto& provider : providers) {
+        if (provider.second == nullptr)
+            continue;
+
+        const auto res = provider.second->GetEntryVersion(title_id);
+        if (res != std::nullopt)
             return res;
     }
 
-    return {};
+    return std::nullopt;
 }
 
-VirtualFile RegisteredCacheUnion::GetEntryUnparsed(u64 title_id, ContentRecordType type) const {
+VirtualFile ContentProviderUnion::GetEntryUnparsed(u64 title_id, ContentRecordType type) const {
-    for (const auto& c : caches) {
+    for (const auto& provider : providers) {
-        const auto res = c->GetEntryUnparsed(title_id, type);
+        if (provider.second == nullptr)
+            continue;
+
+        const auto res = provider.second->GetEntryUnparsed(title_id, type);
         if (res != nullptr)
             return res;
     }
@@ -559,13 +573,12 @@ VirtualFile RegisteredCacheUnion::GetEntryUnparsed(u64 title_id, ContentRecordTy
     return nullptr;
 }
 
-VirtualFile RegisteredCacheUnion::GetEntryUnparsed(RegisteredCacheEntry entry) const {
+VirtualFile ContentProviderUnion::GetEntryRaw(u64 title_id, ContentRecordType type) const {
-    return GetEntryUnparsed(entry.title_id, entry.type);
+    for (const auto& provider : providers) {
-}
+        if (provider.second == nullptr)
+            continue;
 
-VirtualFile RegisteredCacheUnion::GetEntryRaw(u64 title_id, ContentRecordType type) const {
+        const auto res = provider.second->GetEntryRaw(title_id, type);
-    for (const auto& c : caches) {
-        const auto res = c->GetEntryRaw(title_id, type);
         if (res != nullptr)
             return res;
     }
@@ -573,30 +586,30 @@ VirtualFile RegisteredCacheUnion::GetEntryRaw(u64 title_id, ContentRecordType ty
     return nullptr;
 }
 
-VirtualFile RegisteredCacheUnion::GetEntryRaw(RegisteredCacheEntry entry) const {
+std::unique_ptr<NCA> ContentProviderUnion::GetEntry(u64 title_id, ContentRecordType type) const {
-    return GetEntryRaw(entry.title_id, entry.type);
+    for (const auto& provider : providers) {
+        if (provider.second == nullptr)
+            continue;
+
+        auto res = provider.second->GetEntry(title_id, type);
+        if (res != nullptr)
+            return res;
     }
 
-std::unique_ptr<NCA> RegisteredCacheUnion::GetEntry(u64 title_id, ContentRecordType type) const {
-    const auto raw = GetEntryRaw(title_id, type);
-    if (raw == nullptr)
     return nullptr;
-    return std::make_unique<NCA>(raw);
 }
 
-std::unique_ptr<NCA> RegisteredCacheUnion::GetEntry(RegisteredCacheEntry entry) const {
+std::vector<ContentProviderEntry> ContentProviderUnion::ListEntriesFilter(
-    return GetEntry(entry.title_id, entry.type);
+    std::optional<TitleType> title_type, std::optional<ContentRecordType> record_type,
-}
+    std::optional<u64> title_id) const {
+    std::vector<ContentProviderEntry> out;
 
-std::vector<RegisteredCacheEntry> RegisteredCacheUnion::ListEntries() const {
+    for (const auto& provider : providers) {
-    std::vector<RegisteredCacheEntry> out;
+        if (provider.second == nullptr)
-    for (const auto& c : caches) {
+            continue;
-        c->IterateAllMetadata<RegisteredCacheEntry>(
+
-            out,
+        const auto vec = provider.second->ListEntriesFilter(title_type, record_type, title_id);
-            [](const CNMT& c, const ContentRecord& r) {
+        std::copy(vec.begin(), vec.end(), std::back_inserter(out));
-                return RegisteredCacheEntry{c.GetTitleID(), r.type};
-            },
-            [](const CNMT& c, const ContentRecord& r) { return true; });
     }
 
     std::sort(out.begin(), out.end());
@@ -604,25 +617,87 @@ std::vector<RegisteredCacheEntry> RegisteredCacheUnion::ListEntries() const {
     return out;
 }
 
-std::vector<RegisteredCacheEntry> RegisteredCacheUnion::ListEntriesFilter(
+std::vector<std::pair<ContentProviderUnionSlot, ContentProviderEntry>>
+ContentProviderUnion::ListEntriesFilterOrigin(std::optional<ContentProviderUnionSlot> origin,
+                                              std::optional<TitleType> title_type,
+                                              std::optional<ContentRecordType> record_type,
+                                              std::optional<u64> title_id) const {
+    std::vector<std::pair<ContentProviderUnionSlot, ContentProviderEntry>> out;
+
+    for (const auto& provider : providers) {
+        if (provider.second == nullptr)
+            continue;
+
+        if (origin.has_value() && *origin != provider.first)
+            continue;
+
+        const auto vec = provider.second->ListEntriesFilter(title_type, record_type, title_id);
+        std::transform(vec.begin(), vec.end(), std::back_inserter(out),
+                       [&provider](const ContentProviderEntry& entry) {
+                           return std::make_pair(provider.first, entry);
+                       });
+    }
+
+    std::sort(out.begin(), out.end());
+    out.erase(std::unique(out.begin(), out.end()), out.end());
+    return out;
+}
+
+ManualContentProvider::~ManualContentProvider() = default;
+
+void ManualContentProvider::AddEntry(TitleType title_type, ContentRecordType content_type,
+                                     u64 title_id, VirtualFile file) {
+    entries.insert_or_assign({title_type, content_type, title_id}, file);
+}
+
+void ManualContentProvider::ClearAllEntries() {
+    entries.clear();
+}
+
+void ManualContentProvider::Refresh() {}
+
+bool ManualContentProvider::HasEntry(u64 title_id, ContentRecordType type) const {
+    return GetEntryRaw(title_id, type) != nullptr;
+}
+
+std::optional<u32> ManualContentProvider::GetEntryVersion(u64 title_id) const {
+    return std::nullopt;
+}
+
+VirtualFile ManualContentProvider::GetEntryUnparsed(u64 title_id, ContentRecordType type) const {
+    return GetEntryRaw(title_id, type);
+}
+
+VirtualFile ManualContentProvider::GetEntryRaw(u64 title_id, ContentRecordType type) const {
+    const auto iter =
+        std::find_if(entries.begin(), entries.end(), [title_id, type](const auto& entry) {
+            const auto [title_type, content_type, e_title_id] = entry.first;
+            return content_type == type && e_title_id == title_id;
+        });
+    if (iter == entries.end())
+        return nullptr;
+    return iter->second;
+}
+
+std::unique_ptr<NCA> ManualContentProvider::GetEntry(u64 title_id, ContentRecordType type) const {
+    const auto res = GetEntryRaw(title_id, type);
+    if (res == nullptr)
+        return nullptr;
+    return std::make_unique<NCA>(res, nullptr, 0, keys);
+}
+
+std::vector<ContentProviderEntry> ManualContentProvider::ListEntriesFilter(
     std::optional<TitleType> title_type, std::optional<ContentRecordType> record_type,
     std::optional<u64> title_id) const {
-    std::vector<RegisteredCacheEntry> out;
+    std::vector<ContentProviderEntry> out;
-    for (const auto& c : caches) {
+
-        c->IterateAllMetadata<RegisteredCacheEntry>(
+    for (const auto& entry : entries) {
-            out,
+        const auto [e_title_type, e_content_type, e_title_id] = entry.first;
-            [](const CNMT& c, const ContentRecord& r) {
+        if ((title_type == std::nullopt || e_title_type == *title_type) &&
-                return RegisteredCacheEntry{c.GetTitleID(), r.type};
+            (record_type == std::nullopt || e_content_type == *record_type) &&
-            },
+            (title_id == std::nullopt || e_title_id == *title_id)) {
-            [&title_type, &record_type, &title_id](const CNMT& c, const ContentRecord& r) {
+            out.emplace_back(ContentProviderEntry{e_title_id, e_content_type});
-                if (title_type && *title_type != c.GetType())
+        }
-                    return false;
-                if (record_type && *record_type != r.type)
-                    return false;
-                if (title_id && *title_id != c.GetTitleID())
-                    return false;
-                return true;
-            });
     }
 
     std::sort(out.begin(), out.end());

src/core/file_sys/registered_cache.h

@@ -21,12 +21,13 @@ class NSP;
 class XCI;
 
 enum class ContentRecordType : u8;
+enum class NCAContentType : u8;
 enum class TitleType : u8;
 
 struct ContentRecord;
 
 using NcaID = std::array<u8, 0x10>;
-using RegisteredCacheParsingFunction = std::function<VirtualFile(const VirtualFile&, const NcaID&)>;
+using ContentProviderParsingFunction = std::function<VirtualFile(const VirtualFile&, const NcaID&)>;
 using VfsCopyFunction = std::function<bool(const VirtualFile&, const VirtualFile&, size_t)>;
 
 enum class InstallResult {
@@ -36,7 +37,7 @@ enum class InstallResult {
     ErrorMetaFailed,
 };
 
-struct RegisteredCacheEntry {
+struct ContentProviderEntry {
     u64 title_id;
     ContentRecordType type;
 
@@ -47,12 +48,46 @@ constexpr u64 GetUpdateTitleID(u64 base_title_id) {
     return base_title_id | 0x800;
 }
 
+ContentRecordType GetCRTypeFromNCAType(NCAContentType type);
+
 // boost flat_map requires operator< for O(log(n)) lookups.
-bool operator<(const RegisteredCacheEntry& lhs, const RegisteredCacheEntry& rhs);
+bool operator<(const ContentProviderEntry& lhs, const ContentProviderEntry& rhs);
 
 // std unique requires operator== to identify duplicates.
-bool operator==(const RegisteredCacheEntry& lhs, const RegisteredCacheEntry& rhs);
+bool operator==(const ContentProviderEntry& lhs, const ContentProviderEntry& rhs);
-bool operator!=(const RegisteredCacheEntry& lhs, const RegisteredCacheEntry& rhs);
+bool operator!=(const ContentProviderEntry& lhs, const ContentProviderEntry& rhs);
+
+class ContentProvider {
+public:
+    virtual ~ContentProvider();
+
+    virtual void Refresh() = 0;
+
+    virtual bool HasEntry(u64 title_id, ContentRecordType type) const = 0;
+    virtual bool HasEntry(ContentProviderEntry entry) const;
+
+    virtual std::optional<u32> GetEntryVersion(u64 title_id) const = 0;
+
+    virtual VirtualFile GetEntryUnparsed(u64 title_id, ContentRecordType type) const = 0;
+    virtual VirtualFile GetEntryUnparsed(ContentProviderEntry entry) const;
+
+    virtual VirtualFile GetEntryRaw(u64 title_id, ContentRecordType type) const = 0;
+    virtual VirtualFile GetEntryRaw(ContentProviderEntry entry) const;
+
+    virtual std::unique_ptr<NCA> GetEntry(u64 title_id, ContentRecordType type) const = 0;
+    virtual std::unique_ptr<NCA> GetEntry(ContentProviderEntry entry) const;
+
+    virtual std::vector<ContentProviderEntry> ListEntries() const;
+
+    // If a parameter is not std::nullopt, it will be filtered for from all entries.
+    virtual std::vector<ContentProviderEntry> ListEntriesFilter(
+        std::optional<TitleType> title_type = {}, std::optional<ContentRecordType> record_type = {},
+        std::optional<u64> title_id = {}) const = 0;
+
+protected:
+    // A single instance of KeyManager to be used by GetEntry()
+    Core::Crypto::KeyManager keys;
+};
 
 /*
  * A class that catalogues NCAs in the registered directory structure.
@@ -67,39 +102,32 @@ bool operator!=(const RegisteredCacheEntry& lhs, const RegisteredCacheEntry& rhs
  * (This impl also supports substituting the nca dir for an nca file, as that's more convenient
  * when 4GB splitting can be ignored.)
  */
-class RegisteredCache {
+class RegisteredCache : public ContentProvider {
-    friend class RegisteredCacheUnion;
-
 public:
     // Parsing function defines the conversion from raw file to NCA. If there are other steps
     // besides creating the NCA from the file (e.g. NAX0 on SD Card), that should go in a custom
     // parsing function.
     explicit RegisteredCache(VirtualDir dir,
-                             RegisteredCacheParsingFunction parsing_function =
+                             ContentProviderParsingFunction parsing_function =
                                  [](const VirtualFile& file, const NcaID& id) { return file; });
-    ~RegisteredCache();
+    ~RegisteredCache() override;
 
-    void Refresh();
+    void Refresh() override;
 
-    bool HasEntry(u64 title_id, ContentRecordType type) const;
+    bool HasEntry(u64 title_id, ContentRecordType type) const override;
-    bool HasEntry(RegisteredCacheEntry entry) const;
 
-    std::optional<u32> GetEntryVersion(u64 title_id) const;
+    std::optional<u32> GetEntryVersion(u64 title_id) const override;
 
-    VirtualFile GetEntryUnparsed(u64 title_id, ContentRecordType type) const;
+    VirtualFile GetEntryUnparsed(u64 title_id, ContentRecordType type) const override;
-    VirtualFile GetEntryUnparsed(RegisteredCacheEntry entry) const;
 
-    VirtualFile GetEntryRaw(u64 title_id, ContentRecordType type) const;
+    VirtualFile GetEntryRaw(u64 title_id, ContentRecordType type) const override;
-    VirtualFile GetEntryRaw(RegisteredCacheEntry entry) const;
 
-    std::unique_ptr<NCA> GetEntry(u64 title_id, ContentRecordType type) const;
+    std::unique_ptr<NCA> GetEntry(u64 title_id, ContentRecordType type) const override;
-    std::unique_ptr<NCA> GetEntry(RegisteredCacheEntry entry) const;
 
-    std::vector<RegisteredCacheEntry> ListEntries() const;
     // If a parameter is not std::nullopt, it will be filtered for from all entries.
-    std::vector<RegisteredCacheEntry> ListEntriesFilter(
+    std::vector<ContentProviderEntry> ListEntriesFilter(
         std::optional<TitleType> title_type = {}, std::optional<ContentRecordType> record_type = {},
-        std::optional<u64> title_id = {}) const;
+        std::optional<u64> title_id = {}) const override;
 
     // Raw copies all the ncas from the xci/nsp to the csache. Does some quick checks to make sure
     // there is a meta NCA and all of them are accessible.
@@ -131,46 +159,70 @@ private:
     bool RawInstallYuzuMeta(const CNMT& cnmt);
 
     VirtualDir dir;
-    RegisteredCacheParsingFunction parser;
+    ContentProviderParsingFunction parser;
-    Core::Crypto::KeyManager keys;
 
     // maps tid -> NcaID of meta
-    boost::container::flat_map<u64, NcaID> meta_id;
+    std::map<u64, NcaID> meta_id;
     // maps tid -> meta
-    boost::container::flat_map<u64, CNMT> meta;
+    std::map<u64, CNMT> meta;
     // maps tid -> meta for CNMT in yuzu_meta
-    boost::container::flat_map<u64, CNMT> yuzu_meta;
+    std::map<u64, CNMT> yuzu_meta;
 };
 
-// Combines multiple RegisteredCaches (i.e. SysNAND, UserNAND, SDMC) into one interface.
+enum class ContentProviderUnionSlot {
-class RegisteredCacheUnion {
+    SysNAND,        ///< System NAND
+    UserNAND,       ///< User NAND
+    SDMC,           ///< SD Card
+    FrontendManual, ///< Frontend-defined game list or similar
+};
+
+// Combines multiple ContentProvider(s) (i.e. SysNAND, UserNAND, SDMC) into one interface.
+class ContentProviderUnion : public ContentProvider {
 public:
-    explicit RegisteredCacheUnion(std::vector<RegisteredCache*> caches);
+    ~ContentProviderUnion() override;
 
-    void Refresh();
+    void SetSlot(ContentProviderUnionSlot slot, ContentProvider* provider);
+    void ClearSlot(ContentProviderUnionSlot slot);
 
-    bool HasEntry(u64 title_id, ContentRecordType type) const;
+    void Refresh() override;
-    bool HasEntry(RegisteredCacheEntry entry) const;
+    bool HasEntry(u64 title_id, ContentRecordType type) const override;
+    std::optional<u32> GetEntryVersion(u64 title_id) const override;
+    VirtualFile GetEntryUnparsed(u64 title_id, ContentRecordType type) const override;
+    VirtualFile GetEntryRaw(u64 title_id, ContentRecordType type) const override;
+    std::unique_ptr<NCA> GetEntry(u64 title_id, ContentRecordType type) const override;
+    std::vector<ContentProviderEntry> ListEntriesFilter(
+        std::optional<TitleType> title_type, std::optional<ContentRecordType> record_type,
+        std::optional<u64> title_id) const override;
 
-    std::optional<u32> GetEntryVersion(u64 title_id) const;
+    std::vector<std::pair<ContentProviderUnionSlot, ContentProviderEntry>> ListEntriesFilterOrigin(
-
+        std::optional<ContentProviderUnionSlot> origin = {},
-    VirtualFile GetEntryUnparsed(u64 title_id, ContentRecordType type) const;
-    VirtualFile GetEntryUnparsed(RegisteredCacheEntry entry) const;
-
-    VirtualFile GetEntryRaw(u64 title_id, ContentRecordType type) const;
-    VirtualFile GetEntryRaw(RegisteredCacheEntry entry) const;
-
-    std::unique_ptr<NCA> GetEntry(u64 title_id, ContentRecordType type) const;
-    std::unique_ptr<NCA> GetEntry(RegisteredCacheEntry entry) const;
-
-    std::vector<RegisteredCacheEntry> ListEntries() const;
-    // If a parameter is not std::nullopt, it will be filtered for from all entries.
-    std::vector<RegisteredCacheEntry> ListEntriesFilter(
         std::optional<TitleType> title_type = {}, std::optional<ContentRecordType> record_type = {},
         std::optional<u64> title_id = {}) const;
 
 private:
-    std::vector<RegisteredCache*> caches;
+    std::map<ContentProviderUnionSlot, ContentProvider*> providers;
+};
+
+class ManualContentProvider : public ContentProvider {
+public:
+    ~ManualContentProvider() override;
+
+    void AddEntry(TitleType title_type, ContentRecordType content_type, u64 title_id,
+                  VirtualFile file);
+    void ClearAllEntries();
+
+    void Refresh() override;
+    bool HasEntry(u64 title_id, ContentRecordType type) const override;
+    std::optional<u32> GetEntryVersion(u64 title_id) const override;
+    VirtualFile GetEntryUnparsed(u64 title_id, ContentRecordType type) const override;
+    VirtualFile GetEntryRaw(u64 title_id, ContentRecordType type) const override;
+    std::unique_ptr<NCA> GetEntry(u64 title_id, ContentRecordType type) const override;
+    std::vector<ContentProviderEntry> ListEntriesFilter(
+        std::optional<TitleType> title_type, std::optional<ContentRecordType> record_type,
+        std::optional<u64> title_id) const override;
+
+private:
+    std::map<std::tuple<TitleType, ContentRecordType, u64>, VirtualFile> entries;
 };
 
 } // namespace FileSys