DiscIO: Add functions CreateDisc and CreateWAD

...in addition to the existing function CreateVolume
(renamed from CreateVolumeFromFilename).

Lets code easily add constraints such as not letting the user
select a WAD file when using the disc changing functionality.

1 files changed, 41 insertions, 10 deletions

diff --git a/Source/Core/DiscIO/Volume.cpp b/Source/Core/DiscIO/Volume.cpp
index e699e46a93..e1f1bbae4e 100644
--- a/Source/Core/DiscIO/Volume.cpp
+++ b/Source/Core/DiscIO/Volume.cpp
@@ -43,30 +43,61 @@ std::map<Language, std::string> Volume::ReadWiiNames(const std::vector<char16_t>
   return names;
 }
 
-std::unique_ptr<Volume> CreateVolumeFromFilename(const std::string& filename)
+static std::unique_ptr<VolumeDisc> CreateDisc(std::unique_ptr<BlobReader>& reader)
 {
-  std::unique_ptr<BlobReader> reader(CreateBlobReader(filename));
-  if (reader == nullptr)
-    return nullptr;
-
   // Check for Wii
   const std::optional<u32> wii_magic = reader->ReadSwapped<u32>(0x18);
   if (wii_magic == u32(0x5D1C9EA3))
     return std::make_unique<VolumeWii>(std::move(reader));
 
+  // Check for GC
+  const std::optional<u32> gc_magic = reader->ReadSwapped<u32>(0x1C);
+  if (gc_magic == u32(0xC2339F3D))
+    return std::make_unique<VolumeGC>(std::move(reader));
+
+  // No known magic words found
+  return nullptr;
+}
+
+std::unique_ptr<VolumeDisc> CreateDisc(const std::string& path)
+{
+  std::unique_ptr<BlobReader> reader(CreateBlobReader(path));
+  return reader ? CreateDisc(reader) : nullptr;
+}
+
+static std::unique_ptr<VolumeWAD> CreateWAD(std::unique_ptr<BlobReader>& reader)
+{
   // Check for WAD
   // 0x206962 for boot2 wads
   const std::optional<u32> wad_magic = reader->ReadSwapped<u32>(0x02);
   if (wad_magic == u32(0x00204973) || wad_magic == u32(0x00206962))
     return std::make_unique<VolumeWAD>(std::move(reader));
 
-  // Check for GC
-  const std::optional<u32> gc_magic = reader->ReadSwapped<u32>(0x1C);
-  if (gc_magic == u32(0xC2339F3D))
-    return std::make_unique<VolumeGC>(std::move(reader));
-
   // No known magic words found
   return nullptr;
 }
 
+std::unique_ptr<VolumeWAD> CreateWAD(const std::string& path)
+{
+  std::unique_ptr<BlobReader> reader(CreateBlobReader(path));
+  return reader ? CreateWAD(reader) : nullptr;
+}
+
+std::unique_ptr<Volume> CreateVolume(const std::string& path)
+{
+  std::unique_ptr<BlobReader> reader(CreateBlobReader(path));
+  if (reader == nullptr)
+    return nullptr;
+
+  std::unique_ptr<VolumeDisc> disc = CreateDisc(reader);
+  if (disc)
+    return disc;
+
+  std::unique_ptr<VolumeWAD> wad = CreateWAD(reader);
+  if (wad)
+    return wad;
+
+  return nullptr;
+}
+
 }  // namespace DiscIO