From 38304da947c6b593ef94449894dc018aac633344 Mon Sep 17 00:00:00 2001
From: JosJuice <josjuice@gmail.com>
Date: Wed, 2 Aug 2017 18:16:56 +0200
Subject: [PATCH 1/3] DiscIO: Use Common::Lazy for loading filesystems

This simplifies FileMonitor a lot and also lets us
clean up FilesystemPanel.
---
 Source/Core/Common/Lazy.h                     | 10 ++
 Source/Core/Core/HW/DVD/DVDThread.cpp         |  9 +-
 Source/Core/Core/HW/DVD/FileMonitor.cpp       | 39 ++------
 Source/Core/Core/HW/DVD/FileMonitor.h         |  6 +-
 Source/Core/Core/WiiUtils.cpp                 | 28 +++---
 Source/Core/DiscIO/DiscExtractor.cpp          | 21 +++++
 Source/Core/DiscIO/DiscExtractor.h            |  4 +
 Source/Core/DiscIO/DiscScrubber.cpp           |  2 +-
 Source/Core/DiscIO/Filesystem.cpp             | 17 ----
 Source/Core/DiscIO/Filesystem.h               |  8 +-
 Source/Core/DiscIO/Volume.h                   |  3 +
 Source/Core/DiscIO/VolumeFileBlobReader.cpp   | 16 ++--
 Source/Core/DiscIO/VolumeFileBlobReader.h     |  8 +-
 Source/Core/DiscIO/VolumeGC.cpp               | 38 ++++----
 Source/Core/DiscIO/VolumeGC.h                 |  6 ++
 Source/Core/DiscIO/VolumeWad.cpp              |  6 ++
 Source/Core/DiscIO/VolumeWad.h                |  2 +
 Source/Core/DiscIO/VolumeWii.cpp              | 23 +++--
 Source/Core/DiscIO/VolumeWii.h                |  6 +-
 .../ISOProperties/FilesystemPanel.cpp         | 91 +++++++++----------
 .../DolphinWX/ISOProperties/FilesystemPanel.h | 11 +--
 21 files changed, 182 insertions(+), 172 deletions(-)

diff --git a/Source/Core/Common/Lazy.h b/Source/Core/Common/Lazy.h
index 322d4bfeace6..f19d5187cbe7 100644
--- a/Source/Core/Common/Lazy.h
+++ b/Source/Core/Common/Lazy.h
@@ -21,6 +21,16 @@ class Lazy
   Lazy() : m_value(T()) {}
   Lazy(const std::variant<T, std::function<T()>>& value) : m_value(value) {}
   Lazy(std::variant<T, std::function<T()>>&& value) : m_value(std::move(value)) {}
+  const Lazy<T>& operator=(const std::variant<T, std::function<T()>>& value)
+  {
+    m_value = value;
+    return *this;
+  }
+  const Lazy<T>& operator=(std::variant<T, std::function<T()>>&& value)
+  {
+    m_value = std::move(value);
+    return *this;
+  }
   const T& operator*() const { return *ComputeValue(); }
   const T* operator->() const { return ComputeValue(); }
   T& operator*() { return *ComputeValue(); }
diff --git a/Source/Core/Core/HW/DVD/DVDThread.cpp b/Source/Core/Core/HW/DVD/DVDThread.cpp
index 221a95a45110..ebaecbce7e70 100644
--- a/Source/Core/Core/HW/DVD/DVDThread.cpp
+++ b/Source/Core/Core/HW/DVD/DVDThread.cpp
@@ -116,7 +116,6 @@ void Stop()
 {
   StopDVDThread();
   s_disc.reset();
-  FileMonitor::SetFileSystem(nullptr);
 }
 
 static void StopDVDThread()
@@ -160,14 +159,9 @@ void DoState(PointerWrap& p)
   if (had_disc != HasDisc())
   {
     if (had_disc)
-    {
       PanicAlertT("An inserted disc was expected but not found.");
-    }
     else
-    {
       s_disc.reset();
-      FileMonitor::SetFileSystem(nullptr);
-    }
   }
 
   // TODO: Savestates can be smaller if the buffers of results aren't saved,
@@ -185,7 +179,6 @@ void SetDisc(std::unique_ptr<DiscIO::Volume> disc)
 {
   WaitUntilIdle();
   s_disc = std::move(disc);
-  FileMonitor::SetFileSystem(s_disc.get());
 }
 
 bool HasDisc()
@@ -356,7 +349,7 @@ static void DVDThread()
     ReadRequest request;
     while (s_request_queue.Pop(request))
     {
-      FileMonitor::Log(request.dvd_offset, request.partition);
+      FileMonitor::Log(*s_disc, request.partition, request.dvd_offset);
 
       std::vector<u8> buffer(request.length);
       if (!s_disc->Read(request.dvd_offset, request.length, buffer.data(), request.partition))
diff --git a/Source/Core/Core/HW/DVD/FileMonitor.cpp b/Source/Core/Core/HW/DVD/FileMonitor.cpp
index cc50d0ef61c2..2f4dc4965219 100644
--- a/Source/Core/Core/HW/DVD/FileMonitor.cpp
+++ b/Source/Core/Core/HW/DVD/FileMonitor.cpp
@@ -21,10 +21,7 @@
 
 namespace FileMonitor
 {
-static const DiscIO::Volume* s_volume;
-static bool s_new_volume = false;
-static std::unique_ptr<DiscIO::FileSystem> s_filesystem;
-static DiscIO::Partition s_partition;
+static DiscIO::Partition s_previous_partition;
 static std::string s_previous_file;
 
 // Filtered files
@@ -53,42 +50,19 @@ static bool IsSoundFile(const std::string& filename)
   return extensions.find(extension) != extensions.end();
 }
 
-void SetFileSystem(const DiscIO::Volume* volume)
-{
-  // Instead of creating the file system object right away, we will let Log
-  // create it later once we know that it actually will get used
-  s_volume = volume;
-  s_new_volume = true;
-}
-
-// Logs access to files in the file system set by SetFileSystem
-void Log(u64 offset, const DiscIO::Partition& partition)
+void Log(const DiscIO::Volume& volume, const DiscIO::Partition& partition, u64 offset)
 {
   // Do nothing if the log isn't selected
   if (!LogManager::GetInstance()->IsEnabled(LogTypes::FILEMON, LogTypes::LWARNING))
     return;
 
-  // If the volume or partition changed, load the filesystem of the new partition
-  if (s_new_volume || s_partition != partition)
-  {
-    // Discs with partitions don't have PARTITION_NONE filesystems,
-    // so let's not waste time trying to read one
-    const bool reading_from_partition = partition != DiscIO::PARTITION_NONE;
-    const bool disc_has_partitions = !s_volume->GetPartitions().empty();
-    if (reading_from_partition != disc_has_partitions)
-      return;
-
-    s_new_volume = false;
-    s_filesystem = DiscIO::CreateFileSystem(s_volume, partition);
-    s_partition = partition;
-    s_previous_file.clear();
-  }
+  const DiscIO::FileSystem* file_system = volume.GetFileSystem(partition);
 
   // Do nothing if there is no valid file system
-  if (!s_filesystem)
+  if (!file_system)
     return;
 
-  const std::unique_ptr<DiscIO::FileInfo> file_info = s_filesystem->FindFileInfo(offset);
+  const std::unique_ptr<DiscIO::FileInfo> file_info = file_system->FindFileInfo(offset);
 
   // Do nothing if no file was found at that offset
   if (!file_info)
@@ -97,7 +71,7 @@ void Log(u64 offset, const DiscIO::Partition& partition)
   const std::string path = file_info->GetPath();
 
   // Do nothing if we found the same file again
-  if (s_previous_file == path)
+  if (s_previous_partition == partition && s_previous_file == path)
     return;
 
   const std::string size_string = ThousandSeparate(file_info->GetSize() / 1000, 7);
@@ -109,6 +83,7 @@ void Log(u64 offset, const DiscIO::Partition& partition)
     WARN_LOG(FILEMON, "%s", log_string.c_str());
 
   // Update the last accessed file
+  s_previous_partition = partition;
   s_previous_file = path;
 }
 
diff --git a/Source/Core/Core/HW/DVD/FileMonitor.h b/Source/Core/Core/HW/DVD/FileMonitor.h
index f51fc70221a3..2b170f50824d 100644
--- a/Source/Core/Core/HW/DVD/FileMonitor.h
+++ b/Source/Core/Core/HW/DVD/FileMonitor.h
@@ -14,9 +14,5 @@ class Volume;
 
 namespace FileMonitor
 {
-// Can be called with nullptr to set the file system to nothing. When not called
-// with nullptr, the volume must remain valid until the next SetFileSystem call.
-void SetFileSystem(const DiscIO::Volume* volume);
-// Logs access to files in the file system set by SetFileSystem
-void Log(u64 offset, const DiscIO::Partition& partition);
+void Log(const DiscIO::Volume& volume, const DiscIO::Partition& partition, u64 offset);
 }
diff --git a/Source/Core/Core/WiiUtils.cpp b/Source/Core/Core/WiiUtils.cpp
index 14d2024dd0fe..639c05da06be 100644
--- a/Source/Core/Core/WiiUtils.cpp
+++ b/Source/Core/Core/WiiUtils.cpp
@@ -552,7 +552,7 @@ class DiscSystemUpdater final : public SystemUpdater
 
   UpdateCallback m_update_callback;
   std::unique_ptr<DiscIO::Volume> m_volume;
-  std::unique_ptr<DiscIO::FileSystem> m_disc_fs;
+  DiscIO::Partition m_partition;
 };
 
 UpdateResult DiscSystemUpdater::DoDiscUpdate()
@@ -578,16 +578,21 @@ UpdateResult DiscSystemUpdater::DoDiscUpdate()
     return UpdateResult::MissingUpdatePartition;
   }
 
-  m_disc_fs = DiscIO::CreateFileSystem(m_volume.get(), *update_partition);
-  if (!m_disc_fs || !m_disc_fs->IsValid())
-    return UpdateResult::DiscReadFailed;
+  m_partition = *update_partition;
 
   return UpdateFromManifest("__update.inf");
 }
 
 UpdateResult DiscSystemUpdater::UpdateFromManifest(const std::string& manifest_name)
 {
-  const std::unique_ptr<DiscIO::FileInfo> update_manifest = m_disc_fs->FindFileInfo(manifest_name);
+  const DiscIO::FileSystem* disc_fs = m_volume->GetFileSystem(m_partition);
+  if (!disc_fs)
+  {
+    ERROR_LOG(CORE, "Could not read the update partition file system");
+    return UpdateResult::DiscReadFailed;
+  }
+
+  const std::unique_ptr<DiscIO::FileInfo> update_manifest = disc_fs->FindFileInfo(manifest_name);
   if (!update_manifest ||
       (update_manifest->GetSize() - sizeof(ManifestHeader)) % sizeof(Entry) != 0)
   {
@@ -604,8 +609,8 @@ UpdateResult DiscSystemUpdater::UpdateFromManifest(const std::string& manifest_n
   for (u32 i = 0; i < num_entries; ++i)
   {
     const u32 offset = sizeof(ManifestHeader) + sizeof(Entry) * i;
-    if (entry.size() != DiscIO::ReadFile(*m_volume, m_disc_fs->GetPartition(),
-                                         update_manifest.get(), entry.data(), entry.size(), offset))
+    if (entry.size() != DiscIO::ReadFile(*m_volume, m_partition, update_manifest.get(),
+                                         entry.data(), entry.size(), offset))
     {
       ERROR_LOG(CORE, "Failed to read update information from update manifest");
       return UpdateResult::DiscReadFailed;
@@ -654,14 +659,13 @@ UpdateResult DiscSystemUpdater::ProcessEntry(u32 type, std::bitset<32> attrs,
     return UpdateResult::AlreadyUpToDate;
 
   // Import the WAD.
-  const std::unique_ptr<DiscIO::FileInfo> wad_file = m_disc_fs->FindFileInfo(path);
-  if (!wad_file)
+  auto blob = DiscIO::VolumeFileBlobReader::Create(*m_volume, m_partition, path);
+  if (!blob)
   {
-    ERROR_LOG(CORE, "Failed to get info for %s", path.c_str());
+    ERROR_LOG(CORE, "Could not find %s", path.c_str());
     return UpdateResult::DiscReadFailed;
   }
-
-  const DiscIO::WiiWAD wad{DiscIO::VolumeFileBlobReader::Create(*m_volume, *m_disc_fs, path)};
+  const DiscIO::WiiWAD wad{std::move(blob)};
   return InstallWAD(m_ios, wad) ? UpdateResult::Succeeded : UpdateResult::ImportFailed;
 }
 
diff --git a/Source/Core/DiscIO/DiscExtractor.cpp b/Source/Core/DiscIO/DiscExtractor.cpp
index 310ca41e9a7c..e4f52713a50d 100644
--- a/Source/Core/DiscIO/DiscExtractor.cpp
+++ b/Source/Core/DiscIO/DiscExtractor.cpp
@@ -61,6 +61,17 @@ u64 ReadFile(const Volume& volume, const Partition& partition, const FileInfo* f
   return read_length;
 }
 
+u64 ReadFile(const Volume& volume, const Partition& partition, const std::string& path, u8* buffer,
+             u64 max_buffer_size, u64 offset_in_file)
+{
+  const FileSystem* file_system = volume.GetFileSystem(partition);
+  if (!file_system)
+    return 0;
+
+  return ReadFile(volume, partition, file_system->FindFileInfo(path).get(), buffer, max_buffer_size,
+                  offset_in_file);
+}
+
 bool ExportData(const Volume& volume, const Partition& partition, u64 offset, u64 size,
                 const std::string& export_filename)
 {
@@ -98,6 +109,16 @@ bool ExportFile(const Volume& volume, const Partition& partition, const FileInfo
                     export_filename);
 }
 
+bool ExportFile(const Volume& volume, const Partition& partition, const std::string& path,
+                const std::string& export_filename)
+{
+  const FileSystem* file_system = volume.GetFileSystem(partition);
+  if (!file_system)
+    return false;
+
+  return ExportFile(volume, partition, file_system->FindFileInfo(path).get(), export_filename);
+}
+
 void ExportDirectory(const Volume& volume, const Partition partition, const FileInfo& directory,
                      bool recursive, const std::string& filesystem_path,
                      const std::string& export_folder,
diff --git a/Source/Core/DiscIO/DiscExtractor.h b/Source/Core/DiscIO/DiscExtractor.h
index b3a1332c4b09..8157f2027356 100644
--- a/Source/Core/DiscIO/DiscExtractor.h
+++ b/Source/Core/DiscIO/DiscExtractor.h
@@ -19,10 +19,14 @@ std::string DirectoryNameForPartitionType(u32 partition_type);
 
 u64 ReadFile(const Volume& volume, const Partition& partition, const FileInfo* file_info,
              u8* buffer, u64 max_buffer_size, u64 offset_in_file = 0);
+u64 ReadFile(const Volume& volume, const Partition& partition, const std::string& path, u8* buffer,
+             u64 max_buffer_size, u64 offset_in_file = 0);
 bool ExportData(const Volume& volume, const Partition& partition, u64 offset, u64 size,
                 const std::string& export_filename);
 bool ExportFile(const Volume& volume, const Partition& partition, const FileInfo* file_info,
                 const std::string& export_filename);
+bool ExportFile(const Volume& volume, const Partition& partition, const std::string& path,
+                const std::string& export_filename);
 
 // update_progress is called once for each child (file or directory).
 // If update_progress returns true, the extraction gets cancelled.
diff --git a/Source/Core/DiscIO/DiscScrubber.cpp b/Source/Core/DiscIO/DiscScrubber.cpp
index b2fc397eea2d..dac858fcdaa4 100644
--- a/Source/Core/DiscIO/DiscScrubber.cpp
+++ b/Source/Core/DiscIO/DiscScrubber.cpp
@@ -182,7 +182,7 @@ bool DiscScrubber::ParseDisc()
 // Operations dealing with encrypted space are done here
 bool DiscScrubber::ParsePartitionData(const Partition& partition, PartitionHeader* header)
 {
-  std::unique_ptr<FileSystem> filesystem(CreateFileSystem(m_disc.get(), partition));
+  const FileSystem* filesystem = m_disc->GetFileSystem(partition);
   if (!filesystem)
   {
     ERROR_LOG(DISCIO, "Failed to read file system for the partition at 0x%" PRIx64,
diff --git a/Source/Core/DiscIO/Filesystem.cpp b/Source/Core/DiscIO/Filesystem.cpp
index 6171c3004f08..4228afdb7276 100644
--- a/Source/Core/DiscIO/Filesystem.cpp
+++ b/Source/Core/DiscIO/Filesystem.cpp
@@ -4,7 +4,6 @@
 
 #include "DiscIO/Filesystem.h"
 #include <memory>
-#include "DiscIO/FileSystemGCWii.h"
 #include "DiscIO/Volume.h"
 
 namespace DiscIO
@@ -18,20 +17,4 @@ FileSystem::FileSystem(const Volume* volume, const Partition& partition)
 
 FileSystem::~FileSystem() = default;
 
-std::unique_ptr<FileSystem> CreateFileSystem(const Volume* volume, const Partition& partition)
-{
-  if (!volume)
-    return nullptr;
-
-  std::unique_ptr<FileSystem> filesystem = std::make_unique<FileSystemGCWii>(volume, partition);
-
-  if (!filesystem)
-    return nullptr;
-
-  if (!filesystem->IsValid())
-    filesystem.reset();
-
-  return filesystem;
-}
-
 }  // namespace
diff --git a/Source/Core/DiscIO/Filesystem.h b/Source/Core/DiscIO/Filesystem.h
index abfb19778c83..3193e6ca64ff 100644
--- a/Source/Core/DiscIO/Filesystem.h
+++ b/Source/Core/DiscIO/Filesystem.h
@@ -109,8 +109,7 @@ class FileSystem
   FileSystem(const Volume* volume, const Partition& partition);
   virtual ~FileSystem();
 
-  // If IsValid is false, GetRoot must not be called. CreateFileSystem
-  // takes care of this automatically, so other code is recommended to use it.
+  // If IsValid is false, GetRoot must not be called.
   virtual bool IsValid() const = 0;
   // The object returned by GetRoot and all objects created from it
   // are only valid for as long as the file system object is valid.
@@ -126,7 +125,8 @@ class FileSystem
   const Partition m_partition;
 };
 
-// Returns nullptr if a valid file system could not be created
-std::unique_ptr<FileSystem> CreateFileSystem(const Volume* volume, const Partition& partition);
+// Calling Volume::GetFileSystem instead of manually constructing a filesystem is recommended,
+// because it will check IsValid for you, will automatically pick the right type of filesystem,
+// and will cache the filesystem in case it's needed again later.
 
 }  // namespace
diff --git a/Source/Core/DiscIO/Volume.h b/Source/Core/DiscIO/Volume.h
index b4d2965f5a5b..2f075495a642 100644
--- a/Source/Core/DiscIO/Volume.h
+++ b/Source/Core/DiscIO/Volume.h
@@ -21,6 +21,7 @@
 namespace DiscIO
 {
 enum class BlobType;
+class FileSystem;
 
 struct Partition final
 {
@@ -67,6 +68,8 @@ class Volume
     return INVALID_TICKET;
   }
   virtual const IOS::ES::TMDReader& GetTMD(const Partition& partition) const { return INVALID_TMD; }
+  // Returns a non-owning pointer. Returns nullptr if the file system couldn't be read.
+  virtual const FileSystem* GetFileSystem(const Partition& partition) const = 0;
   std::string GetGameID() const { return GetGameID(GetGamePartition()); }
   virtual std::string GetGameID(const Partition& partition) const = 0;
   std::string GetMakerID() const { return GetMakerID(GetGamePartition()); }
diff --git a/Source/Core/DiscIO/VolumeFileBlobReader.cpp b/Source/Core/DiscIO/VolumeFileBlobReader.cpp
index 5b243acc2933..a22800543644 100644
--- a/Source/Core/DiscIO/VolumeFileBlobReader.cpp
+++ b/Source/Core/DiscIO/VolumeFileBlobReader.cpp
@@ -10,23 +10,24 @@
 namespace DiscIO
 {
 std::unique_ptr<VolumeFileBlobReader> VolumeFileBlobReader::Create(const Volume& volume,
-                                                                   const FileSystem& file_system,
+                                                                   const Partition& partition,
                                                                    const std::string& file_path)
 {
-  if (!file_system.IsValid())
+  const FileSystem* file_system = volume.GetFileSystem(partition);
+  if (!file_system)
     return nullptr;
 
-  std::unique_ptr<FileInfo> file_info = file_system.FindFileInfo(file_path);
+  std::unique_ptr<FileInfo> file_info = file_system->FindFileInfo(file_path);
   if (!file_info || file_info->IsDirectory())
     return nullptr;
 
   return std::unique_ptr<VolumeFileBlobReader>{
-      new VolumeFileBlobReader(volume, file_system, std::move(file_info))};
+      new VolumeFileBlobReader(volume, partition, std::move(file_info))};
 }
 
-VolumeFileBlobReader::VolumeFileBlobReader(const Volume& volume, const FileSystem& file_system,
+VolumeFileBlobReader::VolumeFileBlobReader(const Volume& volume, const Partition& partition,
                                            std::unique_ptr<FileInfo> file_info)
-    : m_volume(volume), m_file_system(file_system), m_file_info(std::move(file_info))
+    : m_volume(volume), m_partition(partition), m_file_info(std::move(file_info))
 {
 }
 
@@ -45,7 +46,6 @@ bool VolumeFileBlobReader::Read(u64 offset, u64 length, u8* out_ptr)
   if (offset + length > m_file_info->GetSize())
     return false;
 
-  return m_volume.Read(m_file_info->GetOffset() + offset, length, out_ptr,
-                       m_file_system.GetPartition());
+  return m_volume.Read(m_file_info->GetOffset() + offset, length, out_ptr, m_partition);
 }
 }  // namespace
diff --git a/Source/Core/DiscIO/VolumeFileBlobReader.h b/Source/Core/DiscIO/VolumeFileBlobReader.h
index e915e035604e..46a988d367fb 100644
--- a/Source/Core/DiscIO/VolumeFileBlobReader.h
+++ b/Source/Core/DiscIO/VolumeFileBlobReader.h
@@ -13,14 +13,14 @@
 namespace DiscIO
 {
 class FileInfo;
-class FileSystem;
+struct Partition;
 class Volume;
 
 class VolumeFileBlobReader final : public BlobReader
 {
 public:
   static std::unique_ptr<VolumeFileBlobReader>
-  Create(const Volume& volume, const FileSystem& file_system, const std::string& file_path);
+  Create(const Volume& volume, const Partition& partition, const std::string& file_path);
 
   BlobType GetBlobType() const override { return BlobType::PLAIN; }
   u64 GetDataSize() const override;
@@ -28,11 +28,11 @@ class VolumeFileBlobReader final : public BlobReader
   bool Read(u64 offset, u64 length, u8* out_ptr) override;
 
 private:
-  VolumeFileBlobReader(const Volume& volume, const FileSystem& file_system,
+  VolumeFileBlobReader(const Volume& volume, const Partition& partition,
                        std::unique_ptr<FileInfo> file_info);
 
   const Volume& m_volume;
-  const FileSystem& m_file_system;
+  const Partition& m_partition;
   std::unique_ptr<FileInfo> m_file_info;
 };
 }  // namespace
diff --git a/Source/Core/DiscIO/VolumeGC.cpp b/Source/Core/DiscIO/VolumeGC.cpp
index 46ac57278c7a..01dbd3cfd3ad 100644
--- a/Source/Core/DiscIO/VolumeGC.cpp
+++ b/Source/Core/DiscIO/VolumeGC.cpp
@@ -2,6 +2,7 @@
 // Licensed under GPLv2+
 // Refer to the license.txt file included.
 
+#include <cinttypes>
 #include <cstddef>
 #include <map>
 #include <memory>
@@ -20,6 +21,7 @@
 #include "DiscIO/Blob.h"
 #include "DiscIO/DiscExtractor.h"
 #include "DiscIO/Enums.h"
+#include "DiscIO/FileSystemGCWii.h"
 #include "DiscIO/Filesystem.h"
 #include "DiscIO/Volume.h"
 #include "DiscIO/VolumeGC.h"
@@ -29,6 +31,11 @@ namespace DiscIO
 VolumeGC::VolumeGC(std::unique_ptr<BlobReader> reader) : m_pReader(std::move(reader))
 {
   _assert_(m_pReader);
+
+  m_file_system = [this]() -> std::unique_ptr<FileSystem> {
+    auto file_system = std::make_unique<FileSystemGCWii>(this, PARTITION_NONE);
+    return file_system->IsValid() ? std::move(file_system) : nullptr;
+  };
 }
 
 VolumeGC::~VolumeGC()
@@ -43,6 +50,11 @@ bool VolumeGC::Read(u64 _Offset, u64 _Length, u8* _pBuffer, const Partition& par
   return m_pReader->Read(_Offset, _Length, _pBuffer);
 }
 
+const FileSystem* VolumeGC::GetFileSystem(const Partition& partition) const
+{
+  return m_file_system->get();
+}
+
 std::string VolumeGC::GetGameID(const Partition& partition) const
 {
   static const std::string NO_UID("NO_UID");
@@ -192,30 +204,16 @@ void VolumeGC::LoadBannerFile() const
   m_banner_loaded = true;
 
   GCBanner banner_file;
-  std::unique_ptr<FileSystem> file_system(CreateFileSystem(this, PARTITION_NONE));
-  if (!file_system)
-    return;
-
-  std::unique_ptr<FileInfo> file_info = file_system->FindFileInfo("opening.bnr");
-  if (!file_info)
-    return;
-
-  size_t file_size = static_cast<size_t>(file_info->GetSize());
-  constexpr int BNR1_MAGIC = 0x31524e42;
-  constexpr int BNR2_MAGIC = 0x32524e42;
-  if (file_size != BNR1_SIZE && file_size != BNR2_SIZE)
-  {
-    WARN_LOG(DISCIO, "Invalid opening.bnr. Size: %0zx", file_size);
-    return;
-  }
-
-  if (file_size != ReadFile(*this, PARTITION_NONE, file_info.get(),
-                            reinterpret_cast<u8*>(&banner_file), file_size))
+  const u64 file_size = ReadFile(*this, PARTITION_NONE, "opening.bnr",
+                                 reinterpret_cast<u8*>(&banner_file), sizeof(GCBanner));
+  if (file_size < 4)
   {
     WARN_LOG(DISCIO, "Could not read opening.bnr.");
-    return;
+    return;  // Return early so that we don't access the uninitialized banner_file.id
   }
 
+  constexpr u32 BNR1_MAGIC = 0x31524e42;
+  constexpr u32 BNR2_MAGIC = 0x32524e42;
   bool is_bnr1;
   if (banner_file.id == BNR1_MAGIC && file_size == BNR1_SIZE)
   {
diff --git a/Source/Core/DiscIO/VolumeGC.h b/Source/Core/DiscIO/VolumeGC.h
index f41d58cbcbd3..846c01731cae 100644
--- a/Source/Core/DiscIO/VolumeGC.h
+++ b/Source/Core/DiscIO/VolumeGC.h
@@ -11,6 +11,8 @@
 #include <vector>
 
 #include "Common/CommonTypes.h"
+#include "Common/Lazy.h"
+#include "DiscIO/Filesystem.h"
 #include "DiscIO/Volume.h"
 
 // --- this volume type is used for GC disc images ---
@@ -20,6 +22,7 @@ namespace DiscIO
 class BlobReader;
 enum class BlobType;
 enum class Country;
+class FileSystem;
 enum class Language;
 enum class Region;
 enum class Platform;
@@ -31,6 +34,7 @@ class VolumeGC : public Volume
   ~VolumeGC();
   bool Read(u64 _Offset, u64 _Length, u8* _pBuffer,
             const Partition& partition = PARTITION_NONE) const override;
+  const FileSystem* GetFileSystem(const Partition& partition = PARTITION_NONE) const override;
   std::string GetGameID(const Partition& partition = PARTITION_NONE) const override;
   std::string GetMakerID(const Partition& partition = PARTITION_NONE) const override;
   std::optional<u16> GetRevision(const Partition& partition = PARTITION_NONE) const override;
@@ -93,6 +97,8 @@ class VolumeGC : public Volume
   mutable int m_image_height = 0;
   mutable int m_image_width = 0;
 
+  Common::Lazy<std::unique_ptr<FileSystem>> m_file_system;
+
   std::unique_ptr<BlobReader> m_pReader;
 };
 
diff --git a/Source/Core/DiscIO/VolumeWad.cpp b/Source/Core/DiscIO/VolumeWad.cpp
index 42c0a45bfdf8..4b45f0b706f8 100644
--- a/Source/Core/DiscIO/VolumeWad.cpp
+++ b/Source/Core/DiscIO/VolumeWad.cpp
@@ -65,6 +65,12 @@ bool VolumeWAD::Read(u64 offset, u64 length, u8* buffer, const Partition& partit
   return m_reader->Read(offset, length, buffer);
 }
 
+const FileSystem* VolumeWAD::GetFileSystem(const Partition& partition) const
+{
+  // TODO: Implement this?
+  return nullptr;
+}
+
 Region VolumeWAD::GetRegion() const
 {
   if (!m_tmd.IsValid())
diff --git a/Source/Core/DiscIO/VolumeWad.h b/Source/Core/DiscIO/VolumeWad.h
index d1964bcfa1e9..a97f2d078ef9 100644
--- a/Source/Core/DiscIO/VolumeWad.h
+++ b/Source/Core/DiscIO/VolumeWad.h
@@ -23,6 +23,7 @@ namespace DiscIO
 class BlobReader;
 enum class BlobType;
 enum class Country;
+class FileSystem;
 enum class Language;
 enum class Region;
 enum class Platform;
@@ -34,6 +35,7 @@ class VolumeWAD : public Volume
   ~VolumeWAD();
   bool Read(u64 offset, u64 length, u8* buffer,
             const Partition& partition = PARTITION_NONE) const override;
+  const FileSystem* GetFileSystem(const Partition& partition = PARTITION_NONE) const override;
   std::optional<u64> GetTitleID(const Partition& partition = PARTITION_NONE) const override;
   const IOS::ES::TMDReader& GetTMD(const Partition& partition = PARTITION_NONE) const override;
   std::string GetGameID(const Partition& partition = PARTITION_NONE) const override;
diff --git a/Source/Core/DiscIO/VolumeWii.cpp b/Source/Core/DiscIO/VolumeWii.cpp
index bce96822e7e8..0ed2200f14a6 100644
--- a/Source/Core/DiscIO/VolumeWii.cpp
+++ b/Source/Core/DiscIO/VolumeWii.cpp
@@ -26,6 +26,7 @@
 #include "DiscIO/Blob.h"
 #include "DiscIO/DiscExtractor.h"
 #include "DiscIO/Enums.h"
+#include "DiscIO/FileSystemGCWii.h"
 #include "DiscIO/Filesystem.h"
 #include "DiscIO/Volume.h"
 
@@ -111,10 +112,17 @@ VolumeWii::VolumeWii(std::unique_ptr<BlobReader> reader)
         return aes_context;
       };
 
+      auto get_file_system = [this, partition]() -> std::unique_ptr<FileSystem> {
+        auto file_system = std::make_unique<FileSystemGCWii>(this, partition);
+        return file_system->IsValid() ? std::move(file_system) : nullptr;
+      };
+
       m_partitions.emplace(
           partition, PartitionDetails{Common::Lazy<std::unique_ptr<mbedtls_aes_context>>(get_key),
                                       Common::Lazy<IOS::ES::TicketReader>(get_ticket),
-                                      Common::Lazy<IOS::ES::TMDReader>(get_tmd), *partition_type});
+                                      Common::Lazy<IOS::ES::TMDReader>(get_tmd),
+                                      Common::Lazy<std::unique_ptr<FileSystem>>(get_file_system),
+                                      *partition_type});
     }
   }
 }
@@ -220,6 +228,12 @@ const IOS::ES::TMDReader& VolumeWii::GetTMD(const Partition& partition) const
   return it != m_partitions.end() ? *it->second.tmd : INVALID_TMD;
 }
 
+const FileSystem* VolumeWii::GetFileSystem(const Partition& partition) const
+{
+  auto it = m_partitions.find(partition);
+  return it != m_partitions.end() ? it->second.file_system->get() : nullptr;
+}
+
 u64 VolumeWii::PartitionOffsetToRawOffset(u64 offset, const Partition& partition)
 {
   if (partition == PARTITION_NONE)
@@ -287,13 +301,8 @@ std::string VolumeWii::GetInternalName(const Partition& partition) const
 
 std::map<Language, std::string> VolumeWii::GetLongNames() const
 {
-  std::unique_ptr<FileSystem> file_system(CreateFileSystem(this, GetGamePartition()));
-  if (!file_system)
-    return {};
-
   std::vector<u8> opening_bnr(NAMES_TOTAL_BYTES);
-  std::unique_ptr<FileInfo> file_info = file_system->FindFileInfo("opening.bnr");
-  opening_bnr.resize(ReadFile(*this, GetGamePartition(), file_info.get(), opening_bnr.data(),
+  opening_bnr.resize(ReadFile(*this, GetGamePartition(), "opening.bnr", opening_bnr.data(),
                               opening_bnr.size(), 0x5C));
   return ReadWiiNames(opening_bnr);
 }
diff --git a/Source/Core/DiscIO/VolumeWii.h b/Source/Core/DiscIO/VolumeWii.h
index e702e316ae58..97604887a3a3 100644
--- a/Source/Core/DiscIO/VolumeWii.h
+++ b/Source/Core/DiscIO/VolumeWii.h
@@ -14,15 +14,17 @@
 #include "Common/CommonTypes.h"
 #include "Common/Lazy.h"
 #include "Core/IOS/ES/Formats.h"
+#include "DiscIO/Filesystem.h"
 #include "DiscIO/Volume.h"
 
-// --- this volume type is used for encrypted Wii images ---
+// --- this volume type is used for Wii disc images ---
 
 namespace DiscIO
 {
 class BlobReader;
 enum class BlobType;
 enum class Country;
+class FileSystem;
 enum class Language;
 enum class Region;
 enum class Platform;
@@ -39,6 +41,7 @@ class VolumeWii : public Volume
   std::optional<u64> GetTitleID(const Partition& partition) const override;
   const IOS::ES::TicketReader& GetTicket(const Partition& partition) const override;
   const IOS::ES::TMDReader& GetTMD(const Partition& partition) const override;
+  const FileSystem* GetFileSystem(const Partition& partition) const override;
   std::string GetGameID(const Partition& partition) const override;
   std::string GetMakerID(const Partition& partition) const override;
   std::optional<u16> GetRevision(const Partition& partition) const override;
@@ -72,6 +75,7 @@ class VolumeWii : public Volume
     Common::Lazy<std::unique_ptr<mbedtls_aes_context>> key;
     Common::Lazy<IOS::ES::TicketReader> ticket;
     Common::Lazy<IOS::ES::TMDReader> tmd;
+    Common::Lazy<std::unique_ptr<FileSystem>> file_system;
     u32 type;
   };
 
diff --git a/Source/Core/DolphinWX/ISOProperties/FilesystemPanel.cpp b/Source/Core/DolphinWX/ISOProperties/FilesystemPanel.cpp
index 9888036d2a56..8b3d815af0dd 100644
--- a/Source/Core/DolphinWX/ISOProperties/FilesystemPanel.cpp
+++ b/Source/Core/DolphinWX/ISOProperties/FilesystemPanel.cpp
@@ -36,11 +36,8 @@ namespace
 class WiiPartition final : public wxTreeItemData
 {
 public:
-  WiiPartition(std::unique_ptr<DiscIO::FileSystem> filesystem_) : filesystem{std::move(filesystem_)}
-  {
-  }
-
-  std::unique_ptr<DiscIO::FileSystem> filesystem;
+  WiiPartition(const DiscIO::Partition& partition_) : partition(partition_) {}
+  DiscIO::Partition partition;
 };
 
 enum : int
@@ -86,6 +83,13 @@ void CreateDirectoryTree(wxTreeCtrl* tree_ctrl, wxTreeItemId parent,
   }
 }
 
+void CreateDirectoryTree(wxTreeCtrl* tree_ctrl, wxTreeItemId parent,
+                         const DiscIO::FileSystem* file_system)
+{
+  if (file_system)
+    CreateDirectoryTree(tree_ctrl, parent, file_system->GetRoot());
+}
+
 WiiPartition* FindWiiPartition(wxTreeCtrl* tree_ctrl, const wxString& label)
 {
   wxTreeItemIdValue cookie;
@@ -154,30 +158,22 @@ bool FilesystemPanel::PopulateFileSystemTree()
   {
     for (size_t i = 0; i < partitions.size(); ++i)
     {
-      std::unique_ptr<DiscIO::FileSystem> file_system(
-          DiscIO::CreateFileSystem(m_opened_iso.get(), partitions[i]));
-      if (file_system)
-      {
-        wxTreeItemId partition_root = m_tree_ctrl->AppendItem(
-            m_tree_ctrl->GetRootItem(), wxString::Format(_("Partition %zu"), i), ICON_DISC);
+      wxTreeItemId partition_root = m_tree_ctrl->AppendItem(
+          m_tree_ctrl->GetRootItem(), wxString::Format(_("Partition %zu"), i), ICON_DISC);
 
-        WiiPartition* const partition = new WiiPartition(std::move(file_system));
+      WiiPartition* const partition = new WiiPartition(partitions[i]);
 
-        m_tree_ctrl->SetItemData(partition_root, partition);
-        CreateDirectoryTree(m_tree_ctrl, partition_root, partition->filesystem->GetRoot());
+      m_tree_ctrl->SetItemData(partition_root, partition);
+      CreateDirectoryTree(m_tree_ctrl, partition_root, m_opened_iso->GetFileSystem(partitions[i]));
 
-        if (partitions[i] == m_opened_iso->GetGamePartition())
-          m_tree_ctrl->Expand(partition_root);
-      }
+      if (partitions[i] == m_opened_iso->GetGamePartition())
+        m_tree_ctrl->Expand(partition_root);
     }
   }
   else
   {
-    m_filesystem = DiscIO::CreateFileSystem(m_opened_iso.get(), DiscIO::PARTITION_NONE);
-    if (!m_filesystem)
-      return false;
-
-    CreateDirectoryTree(m_tree_ctrl, m_tree_ctrl->GetRootItem(), m_filesystem->GetRoot());
+    CreateDirectoryTree(m_tree_ctrl, m_tree_ctrl->GetRootItem(),
+                        m_opened_iso->GetFileSystem(DiscIO::PARTITION_NONE));
   }
 
   return true;
@@ -256,7 +252,7 @@ void FilesystemPanel::OnExtractSystemData(wxCommandEvent& event)
     const auto* const selection_data = m_tree_ctrl->GetItemData(m_tree_ctrl->GetSelection());
     const auto* const wii_partition = static_cast<const WiiPartition*>(selection_data);
 
-    partition = wii_partition->filesystem->GetPartition();
+    partition = wii_partition->partition;
   }
   else
   {
@@ -293,11 +289,11 @@ void FilesystemPanel::OnExtractAll(wxCommandEvent& event)
     {
       const auto* const partition = static_cast<WiiPartition*>(m_tree_ctrl->GetItemData(item));
       const std::optional<u32> partition_type =
-          *m_opened_iso->GetPartitionType(partition->filesystem->GetPartition());
+          *m_opened_iso->GetPartitionType(partition->partition);
       if (partition_type)
       {
         const std::string partition_name = DiscIO::DirectoryNameForPartitionType(*partition_type);
-        ExtractPartition(std_extract_path + '/' + partition_name, *partition->filesystem);
+        ExtractPartition(std_extract_path + '/' + partition_name, partition->partition);
       }
       item = m_tree_ctrl->GetNextChild(root, cookie);
     }
@@ -305,11 +301,11 @@ void FilesystemPanel::OnExtractAll(wxCommandEvent& event)
   else if (m_has_partitions && !first_item_selected)
   {
     const auto* const partition = static_cast<WiiPartition*>(m_tree_ctrl->GetItemData(selection));
-    ExtractPartition(std_extract_path, *partition->filesystem);
+    ExtractPartition(std_extract_path, partition->partition);
   }
   else
   {
-    ExtractPartition(std_extract_path, *m_filesystem);
+    ExtractPartition(std_extract_path, DiscIO::PARTITION_NONE);
   }
 }
 
@@ -326,9 +322,8 @@ void FilesystemPanel::OnCheckPartitionIntegrity(wxCommandEvent& WXUNUSED(event))
   const auto selection = m_tree_ctrl->GetSelection();
   WiiPartition* partition =
       static_cast<WiiPartition*>(m_tree_ctrl->GetItemData(m_tree_ctrl->GetSelection()));
-  std::future<bool> is_valid = std::async(std::launch::async, [&] {
-    return m_opened_iso->CheckIntegrity(partition->filesystem->GetPartition());
-  });
+  std::future<bool> is_valid = std::async(
+      std::launch::async, [&] { return m_opened_iso->CheckIntegrity(partition->partition); });
 
   while (is_valid.wait_for(std::chrono::milliseconds(50)) != std::future_status::ready)
     dialog.Pulse();
@@ -350,23 +345,26 @@ void FilesystemPanel::OnCheckPartitionIntegrity(wxCommandEvent& WXUNUSED(event))
 
 void FilesystemPanel::ExtractSingleFile(const wxString& output_file_path) const
 {
-  const std::pair<wxString, const DiscIO::FileSystem&> path = BuildFilePathFromSelection();
-  DiscIO::ExportFile(*m_opened_iso, path.second.GetPartition(),
-                     path.second.FindFileInfo(WxStrToStr(path.first)).get(),
+  const std::pair<wxString, DiscIO::Partition> path = BuildFilePathFromSelection();
+  DiscIO::ExportFile(*m_opened_iso, path.second, WxStrToStr(path.first),
                      WxStrToStr(output_file_path));
 }
 
 void FilesystemPanel::ExtractSingleDirectory(const wxString& output_folder)
 {
-  const std::pair<wxString, const DiscIO::FileSystem&> path = BuildDirectoryPathFromSelection();
+  const std::pair<wxString, DiscIO::Partition> path = BuildDirectoryPathFromSelection();
   ExtractDirectories(WxStrToStr(path.first), WxStrToStr(output_folder), path.second);
 }
 
 void FilesystemPanel::ExtractDirectories(const std::string& full_path,
                                          const std::string& output_folder,
-                                         const DiscIO::FileSystem& filesystem)
+                                         const DiscIO::Partition& partition)
 {
-  std::unique_ptr<DiscIO::FileInfo> file_info = filesystem.FindFileInfo(full_path);
+  const DiscIO::FileSystem* file_system = m_opened_iso->GetFileSystem(partition);
+  if (!file_system)
+    return;
+
+  std::unique_ptr<DiscIO::FileInfo> file_info = file_system->FindFileInfo(full_path);
   u32 size = file_info->GetTotalChildren();
   u32 progress = 0;
 
@@ -376,7 +374,7 @@ void FilesystemPanel::ExtractDirectories(const std::string& full_path,
                               wxPD_ESTIMATED_TIME | wxPD_REMAINING_TIME | wxPD_SMOOTH);
 
   DiscIO::ExportDirectory(
-      *m_opened_iso, filesystem.GetPartition(), *file_info, true, full_path, output_folder,
+      *m_opened_iso, partition, *file_info, true, full_path, output_folder,
       [&](const std::string& path) {
         dialog.SetTitle(wxString::Format(
             "%s : %d%%", dialog_title.c_str(),
@@ -388,13 +386,13 @@ void FilesystemPanel::ExtractDirectories(const std::string& full_path,
 }
 
 void FilesystemPanel::ExtractPartition(const std::string& output_folder,
-                                       const DiscIO::FileSystem& filesystem)
+                                       const DiscIO::Partition& partition)
 {
-  ExtractDirectories("", output_folder + "/files", filesystem);
-  DiscIO::ExportSystemData(*m_opened_iso, filesystem.GetPartition(), output_folder);
+  ExtractDirectories("", output_folder + "/files", partition);
+  DiscIO::ExportSystemData(*m_opened_iso, partition, output_folder);
 }
 
-std::pair<wxString, const DiscIO::FileSystem&> FilesystemPanel::BuildFilePathFromSelection() const
+std::pair<wxString, DiscIO::Partition> FilesystemPanel::BuildFilePathFromSelection() const
 {
   const wxTreeItemId root_node = m_tree_ctrl->GetRootItem();
   wxTreeItemId node = m_tree_ctrl->GetSelection();
@@ -417,22 +415,21 @@ std::pair<wxString, const DiscIO::FileSystem&> FilesystemPanel::BuildFilePathFro
   {
     const size_t slash_index = file_path.find('/');
     const wxString partition_label = file_path.substr(0, slash_index);
-    const auto* const partition = FindWiiPartition(m_tree_ctrl, partition_label);
+    const WiiPartition* const partition = FindWiiPartition(m_tree_ctrl, partition_label);
 
     // Remove "Partition x/"
     file_path.erase(0, slash_index + 1);
 
-    return {file_path, *partition->filesystem};
+    return {file_path, partition->partition};
   }
   else
   {
-    return {file_path, *m_filesystem};
+    return {file_path, DiscIO::PARTITION_NONE};
   }
 }
 
-std::pair<wxString, const DiscIO::FileSystem&>
-FilesystemPanel::BuildDirectoryPathFromSelection() const
+std::pair<wxString, DiscIO::Partition> FilesystemPanel::BuildDirectoryPathFromSelection() const
 {
-  const std::pair<wxString, const DiscIO::FileSystem&> result = BuildFilePathFromSelection();
+  const std::pair<wxString, DiscIO::Partition> result = BuildFilePathFromSelection();
   return {result.first + DIR_SEP_CHR, result.second};
 }
diff --git a/Source/Core/DolphinWX/ISOProperties/FilesystemPanel.h b/Source/Core/DolphinWX/ISOProperties/FilesystemPanel.h
index 59da51ce9544..353afdcca126 100644
--- a/Source/Core/DolphinWX/ISOProperties/FilesystemPanel.h
+++ b/Source/Core/DolphinWX/ISOProperties/FilesystemPanel.h
@@ -15,7 +15,7 @@ class wxTreeEvent;
 
 namespace DiscIO
 {
-class FileSystem;
+struct Partition;
 class Volume;
 }
 
@@ -51,16 +51,15 @@ class FilesystemPanel final : public wxPanel
   void ExtractSingleFile(const wxString& output_file_path) const;
   void ExtractSingleDirectory(const wxString& output_folder);
   void ExtractDirectories(const std::string& full_path, const std::string& output_folder,
-                          const DiscIO::FileSystem& filesystem);
-  void ExtractPartition(const std::string& output_folder, const DiscIO::FileSystem& filesystem);
+                          const DiscIO::Partition& partition);
+  void ExtractPartition(const std::string& output_folder, const DiscIO::Partition& partition);
 
-  std::pair<wxString, const DiscIO::FileSystem&> BuildFilePathFromSelection() const;
-  std::pair<wxString, const DiscIO::FileSystem&> BuildDirectoryPathFromSelection() const;
+  std::pair<wxString, DiscIO::Partition> BuildFilePathFromSelection() const;
+  std::pair<wxString, DiscIO::Partition> BuildDirectoryPathFromSelection() const;
 
   wxTreeCtrl* m_tree_ctrl;
 
   const std::unique_ptr<DiscIO::Volume>& m_opened_iso;
 
-  std::unique_ptr<DiscIO::FileSystem> m_filesystem;
   bool m_has_partitions;
 };

From ca36c977d9617ba188907bbe2ff2922fce121972 Mon Sep 17 00:00:00 2001
From: JosJuice <josjuice@gmail.com>
Date: Wed, 2 Aug 2017 18:34:44 +0200
Subject: [PATCH 2/3] DiscIO: Remove m_partition and m_volume from FileSystem

The last commit made m_partition unnecessary, and m_volume
has been unnecessary ever since the PR that added DiscExtractor.
---
 Source/Core/DiscIO/FileSystemGCWii.cpp | 12 ++++++------
 Source/Core/DiscIO/Filesystem.cpp      |  7 -------
 Source/Core/DiscIO/Filesystem.h        |  6 ------
 3 files changed, 6 insertions(+), 19 deletions(-)

diff --git a/Source/Core/DiscIO/FileSystemGCWii.cpp b/Source/Core/DiscIO/FileSystemGCWii.cpp
index 55afc907c978..e243d0ec72b1 100644
--- a/Source/Core/DiscIO/FileSystemGCWii.cpp
+++ b/Source/Core/DiscIO/FileSystemGCWii.cpp
@@ -185,19 +185,19 @@ bool FileInfoGCWii::IsValid(u64 fst_size, const FileInfoGCWii& parent_directory)
 }
 
 FileSystemGCWii::FileSystemGCWii(const Volume* volume, const Partition& partition)
-    : FileSystem(volume, partition), m_valid(false), m_root(nullptr, 0, 0, 0)
+    : m_valid(false), m_root(nullptr, 0, 0, 0)
 {
   u8 offset_shift;
   // Check if this is a GameCube or Wii disc
-  if (m_volume->ReadSwapped<u32>(0x18, m_partition) == u32(0x5D1C9EA3))
+  if (volume->ReadSwapped<u32>(0x18, partition) == u32(0x5D1C9EA3))
     offset_shift = 2;  // Wii file system
-  else if (m_volume->ReadSwapped<u32>(0x1c, m_partition) == u32(0xC2339F3D))
+  else if (volume->ReadSwapped<u32>(0x1c, partition) == u32(0xC2339F3D))
     offset_shift = 0;  // GameCube file system
   else
     return;  // Invalid partition (maybe someone removed its data but not its partition table entry)
 
-  const std::optional<u64> fst_offset = GetFSTOffset(*m_volume, m_partition);
-  const std::optional<u64> fst_size = GetFSTSize(*m_volume, m_partition);
+  const std::optional<u64> fst_offset = GetFSTOffset(*volume, partition);
+  const std::optional<u64> fst_size = GetFSTSize(*volume, partition);
   if (!fst_offset || !fst_size)
     return;
   if (*fst_size < FST_ENTRY_SIZE)
@@ -220,7 +220,7 @@ FileSystemGCWii::FileSystemGCWii(const Volume* volume, const Partition& partitio
 
   // Read the whole FST
   m_file_system_table.resize(*fst_size);
-  if (!m_volume->Read(*fst_offset, *fst_size, m_file_system_table.data(), m_partition))
+  if (!volume->Read(*fst_offset, *fst_size, m_file_system_table.data(), partition))
   {
     ERROR_LOG(DISCIO, "Couldn't read file system table");
     return;
diff --git a/Source/Core/DiscIO/Filesystem.cpp b/Source/Core/DiscIO/Filesystem.cpp
index 4228afdb7276..9e5336db5d1e 100644
--- a/Source/Core/DiscIO/Filesystem.cpp
+++ b/Source/Core/DiscIO/Filesystem.cpp
@@ -3,18 +3,11 @@
 // Refer to the license.txt file included.
 
 #include "DiscIO/Filesystem.h"
-#include <memory>
-#include "DiscIO/Volume.h"
 
 namespace DiscIO
 {
 FileInfo::~FileInfo() = default;
 
-FileSystem::FileSystem(const Volume* volume, const Partition& partition)
-    : m_volume(volume), m_partition(partition)
-{
-}
-
 FileSystem::~FileSystem() = default;
 
 }  // namespace
diff --git a/Source/Core/DiscIO/Filesystem.h b/Source/Core/DiscIO/Filesystem.h
index 3193e6ca64ff..8d2adbd0a2fb 100644
--- a/Source/Core/DiscIO/Filesystem.h
+++ b/Source/Core/DiscIO/Filesystem.h
@@ -106,7 +106,6 @@ class FileInfo
 class FileSystem
 {
 public:
-  FileSystem(const Volume* volume, const Partition& partition);
   virtual ~FileSystem();
 
   // If IsValid is false, GetRoot must not be called.
@@ -118,11 +117,6 @@ class FileSystem
   virtual std::unique_ptr<FileInfo> FindFileInfo(const std::string& path) const = 0;
   // Returns nullptr if not found
   virtual std::unique_ptr<FileInfo> FindFileInfo(u64 disc_offset) const = 0;
-
-  virtual const Partition GetPartition() const { return m_partition; }
-protected:
-  const Volume* const m_volume;
-  const Partition m_partition;
 };
 
 // Calling Volume::GetFileSystem instead of manually constructing a filesystem is recommended,

From f294599e734f2391db9e74b6454752e75fdf368c Mon Sep 17 00:00:00 2001
From: JosJuice <josjuice@gmail.com>
Date: Wed, 2 Aug 2017 19:06:32 +0200
Subject: [PATCH 3/3] DiscIO: Use Common::Lazy for loading GC banners

---
 Source/Core/DiscIO/VolumeGC.cpp               | 65 +++++++++----------
 Source/Core/DiscIO/VolumeGC.h                 | 29 +++++----
 .../DolphinQt2/Config/FilesystemWidget.cpp    | 17 ++---
 3 files changed, 51 insertions(+), 60 deletions(-)

diff --git a/Source/Core/DiscIO/VolumeGC.cpp b/Source/Core/DiscIO/VolumeGC.cpp
index 01dbd3cfd3ad..b61d273388b4 100644
--- a/Source/Core/DiscIO/VolumeGC.cpp
+++ b/Source/Core/DiscIO/VolumeGC.cpp
@@ -36,6 +36,8 @@ VolumeGC::VolumeGC(std::unique_ptr<BlobReader> reader) : m_pReader(std::move(rea
     auto file_system = std::make_unique<FileSystemGCWii>(this, PARTITION_NONE);
     return file_system->IsValid() ? std::move(file_system) : nullptr;
   };
+
+  m_converted_banner = [this] { return LoadBannerFile(); };
 }
 
 VolumeGC::~VolumeGC()
@@ -125,40 +127,34 @@ std::string VolumeGC::GetInternalName(const Partition& partition) const
 
 std::map<Language, std::string> VolumeGC::GetShortNames() const
 {
-  LoadBannerFile();
-  return m_short_names;
+  return m_converted_banner->short_names;
 }
 
 std::map<Language, std::string> VolumeGC::GetLongNames() const
 {
-  LoadBannerFile();
-  return m_long_names;
+  return m_converted_banner->long_names;
 }
 
 std::map<Language, std::string> VolumeGC::GetShortMakers() const
 {
-  LoadBannerFile();
-  return m_short_makers;
+  return m_converted_banner->short_makers;
 }
 
 std::map<Language, std::string> VolumeGC::GetLongMakers() const
 {
-  LoadBannerFile();
-  return m_long_makers;
+  return m_converted_banner->long_makers;
 }
 
 std::map<Language, std::string> VolumeGC::GetDescriptions() const
 {
-  LoadBannerFile();
-  return m_descriptions;
+  return m_converted_banner->descriptions;
 }
 
 std::vector<u32> VolumeGC::GetBanner(int* width, int* height) const
 {
-  LoadBannerFile();
-  *width = m_image_width;
-  *height = m_image_height;
-  return m_image_buffer;
+  *width = m_converted_banner->image_width;
+  *height = m_converted_banner->image_height;
+  return m_converted_banner->image_buffer;
 }
 
 std::string VolumeGC::GetApploaderDate(const Partition& partition) const
@@ -195,21 +191,15 @@ Platform VolumeGC::GetVolumeType() const
   return Platform::GAMECUBE_DISC;
 }
 
-void VolumeGC::LoadBannerFile() const
+VolumeGC::ConvertedGCBanner VolumeGC::LoadBannerFile() const
 {
-  // If opening.bnr has been loaded already, return immediately
-  if (m_banner_loaded)
-    return;
-
-  m_banner_loaded = true;
-
   GCBanner banner_file;
   const u64 file_size = ReadFile(*this, PARTITION_NONE, "opening.bnr",
                                  reinterpret_cast<u8*>(&banner_file), sizeof(GCBanner));
   if (file_size < 4)
   {
     WARN_LOG(DISCIO, "Could not read opening.bnr.");
-    return;  // Return early so that we don't access the uninitialized banner_file.id
+    return {};  // Return early so that we don't access the uninitialized banner_file.id
   }
 
   constexpr u32 BNR1_MAGIC = 0x31524e42;
@@ -226,14 +216,17 @@ void VolumeGC::LoadBannerFile() const
   else
   {
     WARN_LOG(DISCIO, "Invalid opening.bnr. Type: %0x Size: %0zx", banner_file.id, file_size);
-    return;
+    return {};
   }
 
-  ExtractBannerInformation(banner_file, is_bnr1);
+  return ExtractBannerInformation(banner_file, is_bnr1);
 }
 
-void VolumeGC::ExtractBannerInformation(const GCBanner& banner_file, bool is_bnr1) const
+VolumeGC::ConvertedGCBanner VolumeGC::ExtractBannerInformation(const GCBanner& banner_file,
+                                                               bool is_bnr1) const
 {
+  ConvertedGCBanner banner;
+
   u32 number_of_languages = 0;
   Language start_language = Language::LANGUAGE_UNKNOWN;
 
@@ -249,11 +242,11 @@ void VolumeGC::ExtractBannerInformation(const GCBanner& banner_file, bool is_bnr
     start_language = Language::LANGUAGE_ENGLISH;
   }
 
-  m_image_width = GC_BANNER_WIDTH;
-  m_image_height = GC_BANNER_HEIGHT;
-  m_image_buffer = std::vector<u32>(m_image_width * m_image_height);
-  ColorUtil::decode5A3image(m_image_buffer.data(), banner_file.image, m_image_width,
-                            m_image_height);
+  banner.image_width = GC_BANNER_WIDTH;
+  banner.image_height = GC_BANNER_HEIGHT;
+  banner.image_buffer = std::vector<u32>(GC_BANNER_WIDTH * GC_BANNER_HEIGHT);
+  ColorUtil::decode5A3image(banner.image_buffer.data(), banner_file.image, GC_BANNER_WIDTH,
+                            GC_BANNER_HEIGHT);
 
   for (u32 i = 0; i < number_of_languages; ++i)
   {
@@ -262,24 +255,26 @@ void VolumeGC::ExtractBannerInformation(const GCBanner& banner_file, bool is_bnr
 
     std::string description = DecodeString(info.description);
     if (!description.empty())
-      m_descriptions[language] = description;
+      banner.descriptions.emplace(language, description);
 
     std::string short_name = DecodeString(info.short_name);
     if (!short_name.empty())
-      m_short_names[language] = short_name;
+      banner.short_names.emplace(language, short_name);
 
     std::string long_name = DecodeString(info.long_name);
     if (!long_name.empty())
-      m_long_names[language] = long_name;
+      banner.long_names.emplace(language, long_name);
 
     std::string short_maker = DecodeString(info.short_maker);
     if (!short_maker.empty())
-      m_short_makers[language] = short_maker;
+      banner.short_makers.emplace(language, short_maker);
 
     std::string long_maker = DecodeString(info.long_maker);
     if (!long_maker.empty())
-      m_long_makers[language] = long_maker;
+      banner.long_makers.emplace(language, long_maker);
   }
+
+  return banner;
 }
 
 }  // namespace
diff --git a/Source/Core/DiscIO/VolumeGC.h b/Source/Core/DiscIO/VolumeGC.h
index 846c01731cae..3ba9fdb6fc95 100644
--- a/Source/Core/DiscIO/VolumeGC.h
+++ b/Source/Core/DiscIO/VolumeGC.h
@@ -79,23 +79,26 @@ class VolumeGC : public Volume
                                                     // (only one for BNR1 type)
   };
 
-  void LoadBannerFile() const;
-  void ExtractBannerInformation(const GCBanner& banner_file, bool is_bnr1) const;
+  struct ConvertedGCBanner
+  {
+    std::map<Language, std::string> short_names;
+    std::map<Language, std::string> long_names;
+    std::map<Language, std::string> short_makers;
+    std::map<Language, std::string> long_makers;
+    std::map<Language, std::string> descriptions;
+
+    std::vector<u32> image_buffer;
+    int image_height = 0;
+    int image_width = 0;
+  };
+
+  ConvertedGCBanner LoadBannerFile() const;
+  ConvertedGCBanner ExtractBannerInformation(const GCBanner& banner_file, bool is_bnr1) const;
 
   static const size_t BNR1_SIZE = sizeof(GCBanner) - sizeof(GCBannerInformation) * 5;
   static const size_t BNR2_SIZE = sizeof(GCBanner);
 
-  mutable std::map<Language, std::string> m_short_names;
-
-  mutable std::map<Language, std::string> m_long_names;
-  mutable std::map<Language, std::string> m_short_makers;
-  mutable std::map<Language, std::string> m_long_makers;
-  mutable std::map<Language, std::string> m_descriptions;
-
-  mutable bool m_banner_loaded = false;
-  mutable std::vector<u32> m_image_buffer;
-  mutable int m_image_height = 0;
-  mutable int m_image_width = 0;
+  Common::Lazy<ConvertedGCBanner> m_converted_banner;
 
   Common::Lazy<std::unique_ptr<FileSystem>> m_file_system;
 
diff --git a/Source/Core/DolphinQt2/Config/FilesystemWidget.cpp b/Source/Core/DolphinQt2/Config/FilesystemWidget.cpp
index efb67a2fa700..0b9fc9e0e68a 100644
--- a/Source/Core/DolphinQt2/Config/FilesystemWidget.cpp
+++ b/Source/Core/DolphinQt2/Config/FilesystemWidget.cpp
@@ -85,8 +85,7 @@ void FilesystemWidget::PopulateView()
 
   for (size_t i = 0; i < partitions.size(); i++)
   {
-    std::unique_ptr<DiscIO::FileSystem> file_system(
-        DiscIO::CreateFileSystem(m_volume.get(), partitions[i]));
+    const DiscIO::FileSystem* file_system = m_volume->GetFileSystem(partitions[i]);
 
     auto* item = new QStandardItem(tr("Partition %1").arg(i));
     item->setEditable(false);
@@ -104,10 +103,7 @@ void FilesystemWidget::PopulateView()
   }
 
   if (partitions.empty())
-  {
-    PopulateDirectory(-1, disc,
-                      DiscIO::CreateFileSystem(m_volume.get(), DiscIO::PARTITION_NONE)->GetRoot());
-  }
+    PopulateDirectory(-1, disc, m_volume->GetFileSystem(DiscIO::PARTITION_NONE)->GetRoot());
 }
 
 void FilesystemWidget::PopulateDirectory(int partition_id, QStandardItem* root,
@@ -237,9 +233,7 @@ void FilesystemWidget::ExtractSystemData(const DiscIO::Partition& partition, con
 void FilesystemWidget::ExtractDirectory(const DiscIO::Partition& partition, const QString path,
                                         const QString& out)
 {
-  std::unique_ptr<DiscIO::FileSystem> filesystem(
-      DiscIO::CreateFileSystem(m_volume.get(), partition));
-
+  const DiscIO::FileSystem* filesystem = m_volume->GetFileSystem(partition);
   std::unique_ptr<DiscIO::FileInfo> info = filesystem->FindFileInfo(path.toStdString());
   u32 size = info->GetTotalChildren();
 
@@ -251,7 +245,7 @@ void FilesystemWidget::ExtractDirectory(const DiscIO::Partition& partition, cons
   bool all = path.isEmpty();
 
   DiscIO::ExportDirectory(
-      *m_volume, filesystem->GetPartition(), *info, true, path.toStdString(), out.toStdString(),
+      *m_volume, partition, *info, true, path.toStdString(), out.toStdString(),
       [all, dialog](const std::string& current) {
         dialog->setLabelText(
             (all ? QObject::tr("Extracting All Files...") : QObject::tr("Extracting Directory..."))
@@ -268,8 +262,7 @@ void FilesystemWidget::ExtractDirectory(const DiscIO::Partition& partition, cons
 void FilesystemWidget::ExtractFile(const DiscIO::Partition& partition, const QString& path,
                                    const QString& out)
 {
-  std::unique_ptr<DiscIO::FileSystem> filesystem(
-      DiscIO::CreateFileSystem(m_volume.get(), partition));
+  const DiscIO::FileSystem* filesystem = m_volume->GetFileSystem(partition);
   bool success = DiscIO::ExportFile(
       *m_volume, partition, filesystem->FindFileInfo(path.toStdString()).get(), out.toStdString());