Initial mod mounting code

Author: TheIndra55

src/file/FileSystem.cpp

@@ -1,9 +1,14 @@
 #include "FileSystem.h"
 #include "util/Hooking.h"
 
-cdc::FileSystem* GetFS()
+cdc::FileSystem* GetFS() noexcept
 {
 	auto addr = GET_ADDRESS(0x45C700, 0x45F640, 0x472B50);
 
 	return Hooking::CallReturn<cdc::FileSystem*>(addr);
+}
+
+cdc::FileSystem* GetDiskFS() noexcept
+{
+	return *(cdc::FileSystem**)GET_ADDRESS(0x10E58C0, 0x838890, 0x9CE27C);
 }

src/file/FileSystem.h

@@ -3,4 +3,7 @@
 #include "cdc/file/FileSystem.h"
 
 // Gets the current file system
-cdc::FileSystem* GetFS();
+cdc::FileSystem* GetFS() noexcept;
+
+// Gets the disk file system
+cdc::FileSystem* GetDiskFS() noexcept;

src/file/ModFileSystem.cpp

@@ -0,0 +1,73 @@
+#include "ModFileSystem.h"
+#include "Hook.h"
+
+#include "modules/Log.h"
+#include "file/FileSystem.h"
+
+ModFileSystem::ModFileSystem(const char* path) : m_specMask(1), m_langMask(1), m_path()
+{
+	m_diskSystem = GetDiskFS();
+
+	strcpy(m_basePath, path);
+}
+
+bool ModFileSystem::FindFile(const char* fileName, char* path) const noexcept
+{
+	return false;
+}
+
+cdc::FileRequest* ModFileSystem::RequestRead(cdc::FileReceiver* receiver, const char* fileName, unsigned int startOffset)
+{
+	FindFile(fileName, m_path);
+
+	Hook::GetInstance().GetModule<Log>()->WriteLine("Loading %s from mods folder", fileName);
+
+	return m_diskSystem->RequestRead(receiver, m_path, startOffset);
+}
+
+cdc::File* ModFileSystem::OpenFile(const char* fileName)
+{
+	FindFile(fileName, m_path);
+
+	return m_diskSystem->OpenFile(m_path);
+}
+
+bool ModFileSystem::FileExists(const char* fileName)
+{
+	return FindFile(fileName, m_path);
+}
+
+unsigned int ModFileSystem::GetFileSize(const char* fileName)
+{
+	FindFile(fileName, m_path);
+
+	return m_diskSystem->GetFileSize(m_path);
+}
+
+void ModFileSystem::SetSpecialisationMask(unsigned int specMask)
+{
+	m_specMask = specMask;
+
+	// Unset extra bit and set our language mask
+	m_langMask = specMask & ~0x80000000;
+}
+
+unsigned int ModFileSystem::GetSpecialisationMask()
+{
+	return m_specMask;
+}
+
+cdc::FileSystem::Status ModFileSystem::GetStatus()
+{
+	return m_diskSystem->GetStatus();
+}
+
+void ModFileSystem::Update()
+{
+	m_diskSystem->Update();
+}
+
+void ModFileSystem::Synchronize()
+{
+	m_diskSystem->Synchronize();
+}

src/file/ModFileSystem.h

@@ -0,0 +1,43 @@
+#pragma once
+
+#include "cdc/file/FileSystem.h"
+
+// So we don't need to include Windows.h here
+#define _MAX_PATH 260
+
+// This file system represents a subfolder in the mods oflder
+class ModFileSystem : public cdc::FileSystem
+{
+private:
+	cdc::FileSystem* m_diskSystem;
+
+	unsigned int m_specMask;
+	unsigned int m_langMask;
+
+	char m_basePath[_MAX_PATH];
+	char m_path[_MAX_PATH];
+
+	// Finds a file and returns whether it exists and the rewritten path
+	bool FindFile(const char* fileName, char* path) const noexcept;
+
+public:
+	ModFileSystem(const char* path);
+
+	cdc::FileRequest* RequestRead(cdc::FileReceiver* receiver, const char* fileName, unsigned int startOffset);
+	cdc::File* OpenFile(const char* fileName);
+	bool FileExists(const char* fileName);
+	unsigned int GetFileSize(const char* fileName);
+	void SetSpecialisationMask(unsigned int specMask);
+	unsigned int GetSpecialisationMask();
+	Status GetStatus();
+	void Update();
+	void Synchronize();
+
+#ifdef TR8
+	void Suspend();
+	bool Resume();
+	bool IsSuspended();
+	char* GetBufferPointer(cdc::FileRequest* request, unsigned int* bytesLocked);
+	void ResetBufferPointer(int value);
+#endif
+};

src/file/MultiFileSystem.cpp

@@ -1,5 +1,8 @@
  #include "MultiFileSystem.h"
 
+#include "Hook.h"
+#include "modules/Log.h"
+
 MultiFileSystem::MultiFileSystem() : m_fileSystems()
 {
 }
@@ -21,6 +24,8 @@ cdc::FileSystem* MultiFileSystem::GetBestFileSystem(const char* fileName)
 void MultiFileSystem::Add(cdc::FileSystem* fileSystem)
 {
 	m_fileSystems.push_back(fileSystem);
+
+	Hook::GetInstance().GetModule<Log>()->WriteLine("Mounted new file system %p, number of systems: %d", fileSystem, m_fileSystems.size());
 }
 
 void MultiFileSystem::Remove(cdc::FileSystem* fileSystem)

src/modules/ModLoader.cpp

@@ -2,13 +2,19 @@
 #include <MinHook.h>
 
 #include "ModLoader.h"
+#include "Hook.h"
+#include "Log.h"
 #include "util/Hooking.h"
 
 #include "cdc/file/MultiFileSystem.h"
+#include "cdc/file/ArchiveFileSystem.h"
 
 #include "file/FileSystem.h"
 #include "file/HookFileSystem.h"
 #include "file/MultiFileSystem.h"
+#include "file/ModFileSystem.h"
+
+static ModLoader* loader = nullptr;
 
 static cdc::FileSystem* CreateHookFileSystem()
 {
@@ -43,10 +49,9 @@ static void InitArchive()
 
 	// Create our hook file system and multi file system
 	auto fileSystem = CreateHookFileSystem();
-	auto multiFileSystem = new MultiFileSystem();
+	auto multiFileSystem = loader->GetFileSystem();
 
-	//auto archiveFile = new cdc::ArchiveFileSystem(*(cdc::FileSystem**)0x838890);
-	//archiveFile->Open("mods/bigfile.000");
+	loader->MountMods();
 
 	multiFileSystem->Add(fileSystem);
 	multiFileSystem->Add(GetFS());
@@ -56,13 +61,67 @@ static void InitArchive()
 }
 
 // Initialize the mod loader and insert all hooks
-ModLoader::ModLoader()
+ModLoader::ModLoader() : m_fileSystem()
 {
+	loader = this;
+
 #ifndef TR8
 	MH_CreateHook((void*)GET_ADDRESS(0x45C670, 0x45F5B0, 0x473840), InitArchive, (void**)&s_InitArchive);
 #else
 	MH_CreateHook((void*)0x478930, InitPatchArchive, (void**)&s_InitPatchArchive);
 #endif
 
 	MH_EnableHook(MH_ALL_HOOKS);
+}
+
+void ModLoader::MountMods()
+{
+	auto log = Hook::GetInstance().GetModule<Log>();
+
+	for (auto& entry : std::filesystem::directory_iterator("mods"))
+	{
+		auto name = entry.path().filename();
+
+		// Mount files with bigfile extension as archive
+		if (entry.is_regular_file() && name.extension() == ".000")
+		{
+			log->WriteLine("Mounting mod archive %s", name.string().c_str());
+
+			MountArchive(name);
+		}
+
+		// Mount folders as new mod file system
+		if (entry.is_directory())
+		{
+			log->WriteLine("Mounting mod directory %s", name.string().c_str());
+
+			MountDirectory(name);
+		}
+	}
+}
+
+void ModLoader::MountArchive(std::filesystem::path& name) noexcept
+{
+	auto path = "mods" / name;
+
+	// Open the archive
+	auto archive = new cdc::ArchiveFileSystem(*(cdc::FileSystem**)0x838890);
+	archive->Open(path.string().c_str());
+
+	// Mount the archive
+	m_fileSystem.Add((cdc::FileSystem*)archive);
+}
+
+void ModLoader::MountDirectory(std::filesystem::path& name) noexcept
+{
+	auto path = "mods" / name;
+	auto fileSystem = new ModFileSystem(name.string().c_str());
+
+	// Mount the file system
+	m_fileSystem.Add(fileSystem);
+}
+
+MultiFileSystem* ModLoader::GetFileSystem() noexcept
+{
+	return &m_fileSystem;
 }

src/modules/ModLoader.h

@@ -1,9 +1,21 @@
 #pragma once
 
+#include <filesystem>
+
 #include "Module.h"
+#include "file/MultiFileSystem.h"
 
 class ModLoader : public Module
 {
+private:
+	MultiFileSystem m_fileSystem;
+
+	void MountArchive(std::filesystem::path& name) noexcept;
+	void MountDirectory(std::filesystem::path& name) noexcept;
+
 public:
 	ModLoader();
+	void MountMods();
+
+	MultiFileSystem* GetFileSystem() noexcept;
 };