Core: Add ability to specify and launch a riivolution-modded game via a .json file.

1 files changed, 147 insertions, 0 deletions

diff --git a/Source/Core/DiscIO/GameModDescriptor.cpp b/Source/Core/DiscIO/GameModDescriptor.cpp
new file mode 100644
index 0000000000..4a1c479fca
--- /dev/null
+++ b/Source/Core/DiscIO/GameModDescriptor.cpp
@@ -0,0 +1,147 @@
+// Copyright 2021 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <optional>
+#include <string>
+#include <string_view>
+#include <vector>
+
+#include "DiscIO/GameModDescriptor.h"
+
+#include <picojson.h>
+
+#include "Common/IOFile.h"
+#include "Common/MathUtil.h"
+#include "Common/StringUtil.h"
+
+namespace DiscIO
+{
+static std::string MakeAbsolute(const std::string& directory, const std::string& path)
+{
+#ifdef _WIN32
+  return PathToString(StringToPath(directory) / StringToPath(path));
+#else
+  if (StringBeginsWith(path, "/"))
+    return path;
+  return directory + "/" + path;
+#endif
+}
+
+std::optional<GameModDescriptor> ParseGameModDescriptorFile(const std::string& filename)
+{
+  ::File::IOFile f(filename, "rb");
+  if (!f)
+    return std::nullopt;
+
+  std::vector<char> data;
+  data.resize(f.GetSize());
+  if (!f.ReadBytes(data.data(), data.size()))
+    return std::nullopt;
+
+#ifdef _WIN32
+  std::string path = ReplaceAll(filename, "\\", "/");
+#else
+  const std::string& path = filename;
+#endif
+  return ParseGameModDescriptorString(std::string_view(data.data(), data.size()), path);
+}
+
+static std::vector<GameModDescriptorRiivolutionPatchOption>
+ParseRiivolutionOptions(const picojson::array& array)
+{
+  std::vector<GameModDescriptorRiivolutionPatchOption> options;
+  for (const auto& option_object : array)
+  {
+    if (!option_object.is<picojson::object>())
+      continue;
+
+    auto& option = options.emplace_back();
+    for (const auto& [key, value] : option_object.get<picojson::object>())
+    {
+      if (key == "section-name" && value.is<std::string>())
+        option.section_name = value.get<std::string>();
+      else if (key == "option-id" && value.is<std::string>())
+        option.option_id = value.get<std::string>();
+      else if (key == "option-name" && value.is<std::string>())
+        option.option_name = value.get<std::string>();
+      else if (key == "choice" && value.is<double>())
+        option.choice = MathUtil::SaturatingCast<u32>(value.get<double>());
+    }
+  }
+  return options;
+}
+
+static GameModDescriptorRiivolution ParseRiivolutionObject(const std::string& json_directory,
+                                                           const picojson::object& object)
+{
+  GameModDescriptorRiivolution r;
+  for (const auto& [element_key, element_value] : object)
+  {
+    if (element_key == "patches" && element_value.is<picojson::array>())
+    {
+      for (const auto& patch_object : element_value.get<picojson::array>())
+      {
+        if (!patch_object.is<picojson::object>())
+          continue;
+
+        auto& patch = r.patches.emplace_back();
+        for (const auto& [key, value] : patch_object.get<picojson::object>())
+        {
+          if (key == "xml" && value.is<std::string>())
+            patch.xml = MakeAbsolute(json_directory, value.get<std::string>());
+          else if (key == "root" && value.is<std::string>())
+            patch.root = MakeAbsolute(json_directory, value.get<std::string>());
+          else if (key == "options" && value.is<picojson::array>())
+            patch.options = ParseRiivolutionOptions(value.get<picojson::array>());
+        }
+      }
+    }
+  }
+  return r;
+}
+
+std::optional<GameModDescriptor> ParseGameModDescriptorString(std::string_view json,
+                                                              std::string_view json_path)
+{
+  std::string json_directory;
+  SplitPath(json_path, &json_directory, nullptr, nullptr);
+
+  picojson::value json_root;
+  std::string err;
+  picojson::parse(json_root, json.begin(), json.end(), &err);
+  if (!err.empty())
+    return std::nullopt;
+  if (!json_root.is<picojson::object>())
+    return std::nullopt;
+
+  GameModDescriptor descriptor;
+  bool is_valid_version = false;
+  for (const auto& [key, value] : json_root.get<picojson::object>())
+  {
+    if (key == "version" && value.is<double>())
+    {
+      is_valid_version = value.get<double>() == 1.0;
+    }
+    else if (key == "base-file" && value.is<std::string>())
+    {
+      descriptor.base_file = MakeAbsolute(json_directory, value.get<std::string>());
+    }
+    else if (key == "display-name" && value.is<std::string>())
+    {
+      descriptor.display_name = value.get<std::string>();
+    }
+    else if (key == "banner" && value.is<std::string>())
+    {
+      descriptor.banner = MakeAbsolute(json_directory, value.get<std::string>());
+    }
+    else if (key == "riivolution" && value.is<picojson::object>())
+    {
+      descriptor.riivolution =
+          ParseRiivolutionObject(json_directory, value.get<picojson::object>());
+    }
+  }
+  if (!is_valid_version)
+    return std::nullopt;
+  return descriptor;
+}
+}  // namespace DiscIO