[FS] Implement OpenDirectory

include/fs/archive_base.hpp

@@ -2,6 +2,7 @@
 #include <cassert>
 #include <cstdio>
 #include <cstring>
+#include <filesystem>
 #include <optional>
 #include <string>
 #include <type_traits>
@@ -111,6 +112,17 @@ struct ArchiveSession {
     ArchiveSession(ArchiveBase* archive, const FSPath& filePath, bool isOpen = true) : archive(archive), path(filePath), isOpen(isOpen) {}
 };
 
+struct DirectorySession {
+    ArchiveBase* archive = nullptr;
+    // For directories which are mirrored to a specific path on the disk, this contains that path
+    // Otherwise this is a nullopt
+    std::optional<std::filesystem::path> pathOnDisk;
+    bool isOpen;
+
+    DirectorySession(ArchiveBase* archive, std::filesystem::path path, bool isOpen = true) : archive(archive), pathOnDisk(path),
+        isOpen(isOpen) {}
+};
+
 // Represents a file descriptor obtained from OpenFile. If the optional is nullopt, opening the file failed.
 // Otherwise the fd of the opened file is returned (or nullptr if the opened file doesn't require one)
 using FileDescriptor = std::optional<FILE*>;
@@ -201,6 +213,10 @@ public:
     virtual FileDescriptor openFile(const FSPath& path, const FilePerms& perms) = 0;
 
     virtual ArchiveBase* openArchive(const FSPath& path) = 0;
+    virtual std::optional<DirectorySession> openDirectory(const FSPath& path) {
+        Helpers::panic("Unimplemented OpenDirectory for %s archive", name().c_str());
+        return std::nullopt;
+    }
 
     // Read size bytes from a file starting at offset "offset" into a certain buffer in memory
     // Returns the number of bytes read, or nullopt if the read failed

include/fs/archive_save_data.hpp

@@ -13,6 +13,7 @@ public:
 	FormatInfo getFormatInfo(const FSPath& path) override;
 
 	ArchiveBase* openArchive(const FSPath& path) override;
+	std::optional<DirectorySession> openDirectory(const FSPath& path) override;
 	FileDescriptor openFile(const FSPath& path, const FilePerms& perms) override;
 	std::optional<u32> readFile(FileSession* file, u64 offset, u32 size, u32 dataPointer) override;
 

include/kernel/kernel_types.hpp

@@ -27,7 +27,7 @@ namespace SVCResult {
 }
 
 enum class KernelObjectType : u8 {
-    AddressArbiter, Archive, File, MemoryBlock, Process, ResourceLimit, Session, Dummy,
+    AddressArbiter, Archive, Directory, File, MemoryBlock, Process, ResourceLimit, Session, Dummy,
     // Bundle waitable objects together in the enum to let the compiler optimize certain checks better
     Event, Mutex, Port, Semaphore, Timer, Thread
 };
@@ -144,6 +144,7 @@ static const char* kernelObjectTypeToString(KernelObjectType t) {
     switch (t) {
         case KernelObjectType::AddressArbiter: return "address arbiter";
         case KernelObjectType::Archive: return "archive";
+        case KernelObjectType::Directory: return "directory";
         case KernelObjectType::Event: return "event";
         case KernelObjectType::File: return "file";
         case KernelObjectType::MemoryBlock: return "memory block";

include/services/fs.hpp

@@ -29,6 +29,7 @@ class FSService {
 
 	ArchiveBase* getArchiveFromID(u32 id);
 	std::optional<Handle> openArchiveHandle(u32 archiveID, const FSPath& path);
+	std::optional<Handle> openDirectoryHandle(ArchiveBase* archive, const FSPath& path);
 	std::optional<Handle> openFileHandle(ArchiveBase* archive, const FSPath& path, const FSPath& archivePath, const FilePerms& perms);
 	FSPath readPath(u32 type, u32 pointer, u32 size);
 
@@ -42,6 +43,7 @@ class FSService {
 	void initializeWithSdkVersion(u32 messagePointer);
 	void isSdmcDetected(u32 messagePointer);
 	void openArchive(u32 messagePointer);
+	void openDirectory(u32 messagePointer);
 	void openFile(u32 messagePointer);
 	void openFileDirectly(u32 messagePointer);
 	void setPriority(u32 messagePointer);