WinUpdater: Check OS and VC++ Redist versions.

Source/Core/UpdaterCommon/Platform.h

@@ -0,0 +1,100 @@
+// Copyright 2018 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <map>
+#include <optional>
+#include <sstream>
+
+#include "Common/CommonTypes.h"
+#include "Common/StringUtil.h"
+
+namespace Platform
+{
+struct BuildVersion
+{
+  u32 major{};
+  u32 minor{};
+  u32 build{};
+  auto operator<=>(BuildVersion const& rhs) const = default;
+  static std::optional<BuildVersion> from_string(const std::string& str)
+  {
+    auto components = SplitString(str, '.');
+    // Allow variable number of components (truncating after "build"), but not
+    // empty.
+    if (components.size() == 0)
+      return {};
+    BuildVersion version;
+    if (!TryParse(components[0], &version.major, 10))
+      return {};
+    if (components.size() > 1 && !TryParse(components[1], &version.minor, 10))
+      return {};
+    if (components.size() > 2 && !TryParse(components[2], &version.build, 10))
+      return {};
+    return version;
+  }
+};
+
+enum class VersionCheckStatus
+{
+  NothingToDo,
+  UpdateOptional,
+  UpdateRequired,
+};
+
+struct VersionCheckResult
+{
+  VersionCheckStatus status{VersionCheckStatus::NothingToDo};
+  std::optional<BuildVersion> current_version{};
+  std::optional<BuildVersion> target_version{};
+};
+
+class BuildInfo
+{
+  using Map = std::map<std::string, std::string>;
+
+public:
+  BuildInfo() = default;
+  BuildInfo(const std::string& content);
+
+  std::optional<std::string> GetString(const std::string& name) const
+  {
+    auto it = map.find(name);
+    if (it == map.end() || it->second.size() == 0)
+      return {};
+    return it->second;
+  }
+
+  std::optional<BuildVersion> GetVersion(const std::string& name) const
+  {
+    auto str = GetString(name);
+    if (!str.has_value())
+      return {};
+    return BuildVersion::from_string(str.value());
+  }
+
+private:
+  void Parse(const std::string& content)
+  {
+    std::stringstream content_stream(content);
+    std::string line;
+    while (std::getline(content_stream, line))
+    {
+      if (line.starts_with("//"))
+        continue;
+      const size_t equals_index = line.find('=');
+      if (equals_index == line.npos)
+        continue;
+      auto key = line.substr(0, equals_index);
+      auto key_it = map.find(key);
+      if (key_it == map.end())
+        continue;
+      key_it->second = line.substr(equals_index + 1);
+    }
+  }
+  Map map;
+};
+
+bool VersionCheck(const BuildInfo& this_build_info, const BuildInfo& next_build_info);
+}  // namespace Platform

Source/Core/UpdaterCommon/UpdaterCommon.cpp

@@ -18,6 +18,7 @@
 #include "Common/HttpRequest.h"
 #include "Common/ScopeGuard.h"
 #include "Common/StringUtil.h"
+#include "UpdaterCommon/Platform.h"
 #include "UpdaterCommon/UI.h"
 
 #ifndef _WIN32
@@ -278,6 +279,41 @@ bool DownloadContent(const std::vector<TodoList::DownloadOp>& to_download,
   return true;
 }
 
+bool PlatformVersionCheck(const std::vector<TodoList::UpdateOp>& to_update,
+                          const std::string& install_base_path, const std::string& temp_dir)
+{
+  UI::SetDescription("Checking platform...");
+
+  const auto op_it = std::find_if(to_update.cbegin(), to_update.cend(),
+                                  [&](const auto& op) { return op.filename == "build_info.txt"; });
+  if (op_it == to_update.cend())
+    return true;
+
+  const auto op = *op_it;
+  std::string build_info_path =
+      temp_dir + DIR_SEP + HexEncode(op.new_hash.data(), op.new_hash.size());
+  std::string build_info_content;
+  if (!File::ReadFileToString(build_info_path, build_info_content) ||
+      op.new_hash != ComputeHash(build_info_content))
+  {
+    fprintf(log_fp, "Failed to read %s\n.", build_info_path.c_str());
+    return false;
+  }
+  auto next_build_info = Platform::BuildInfo(build_info_content);
+
+  build_info_path = install_base_path + DIR_SEP + "build_info.txt";
+  auto this_build_info = Platform::BuildInfo();
+  if (File::ReadFileToString(build_info_path, build_info_content))
+  {
+    if (op.old_hash != ComputeHash(build_info_content))
+      fprintf(log_fp, "Using modified existing BuildInfo %s.\n", build_info_path.c_str());
+    this_build_info = Platform::BuildInfo(build_info_content);
+  }
+
+  // The existing BuildInfo may have been modified. Be careful not to overly trust its contents!
+  return Platform::VersionCheck(this_build_info, next_build_info);
+}
+
 TodoList ComputeActionsToDo(Manifest this_manifest, Manifest next_manifest)
 {
   TodoList todo;
@@ -474,6 +510,11 @@ bool PerformUpdate(const TodoList& todo, const std::string& install_base_path,
     return false;
   fprintf(log_fp, "Download step completed.\n");
 
+  fprintf(log_fp, "Starting platform version check step...\n");
+  if (!PlatformVersionCheck(todo.to_update, install_base_path, temp_path))
+    return false;
+  fprintf(log_fp, "Platform version check step completed.\n");
+
   fprintf(log_fp, "Starting update step...\n");
   if (!UpdateFiles(todo.to_update, install_base_path, temp_path))
     return false;