Move shared Updater logic into UpdaterCommon

Source/Core/UpdaterCommon/UpdaterCommon.h

@@ -0,0 +1,60 @@
+// Copyright 2019 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <array>
+#include <cstdio>
+#include <map>
+#include <optional>
+#include <string>
+#include <vector>
+
+#include "Common/CommonTypes.h"
+
+extern FILE* log_fp;
+
+struct Manifest
+{
+  using Filename = std::string;
+  using Hash = std::array<u8, 16>;
+  std::map<Filename, Hash> entries;
+};
+
+// Represent the operations to be performed by the updater.
+struct TodoList
+{
+  struct DownloadOp
+  {
+    Manifest::Filename filename;
+    Manifest::Hash hash;
+  };
+  std::vector<DownloadOp> to_download;
+
+  struct UpdateOp
+  {
+    Manifest::Filename filename;
+    std::optional<Manifest::Hash> old_hash;
+    Manifest::Hash new_hash;
+  };
+  std::vector<UpdateOp> to_update;
+
+  struct DeleteOp
+  {
+    Manifest::Filename filename;
+    Manifest::Hash old_hash;
+  };
+  std::vector<DeleteOp> to_delete;
+
+  void Log() const;
+};
+
+void FatalError(const std::string& message);
+std::optional<Manifest> FetchAndParseManifest(const std::string& url);
+TodoList ComputeActionsToDo(Manifest this_manifest, Manifest next_manifest);
+std::optional<std::string> FindOrCreateTempDir(const std::string& base_path);
+void CleanUpTempDir(const std::string& temp_dir, const TodoList& todo);
+bool PerformUpdate(const TodoList& todo, const std::string& install_base_path,
+                   const std::string& content_base_url, const std::string& temp_path);
+void FlushLog();