Use placeholders for serialized paths

src/common/file_util.cpp

@@ -729,6 +729,33 @@ void SetUserPath(const std::string& path) {
     g_paths.emplace(UserPath::StatesDir, user_path + STATES_DIR DIR_SEP);
 }
 
+std::string g_currentRomPath{};
+
+void SetCurrentRomPath(const std::string& path) {
+    g_currentRomPath = path;
+}
+
+bool StringReplace(std::string& haystack, const std::string& a, const std::string& b, bool swap) {
+    const auto& needle = swap ? b : a;
+    const auto& replacement = swap ? a : b;
+    if (needle.empty()) {
+        return false;
+    }
+    auto index = haystack.find(needle, 0);
+    if (index == std::string::npos) {
+        return false;
+    }
+    haystack.replace(index, needle.size(), replacement);
+    return true;
+}
+
+std::string SerializePath(const std::string& input, bool is_saving) {
+    auto result = input;
+    StringReplace(result, "%CITRA_ROM_FILE%", g_currentRomPath, is_saving);
+    StringReplace(result, "%CITRA_USER_DIR%", GetUserPath(UserPath::UserDir), is_saving);
+    return result;
+}
+
 const std::string& GetUserPath(UserPath path) {
     // Set up all paths and files on the first run
     if (g_paths.empty())

src/common/file_util.h

@@ -140,10 +140,15 @@ bool SetCurrentDir(const std::string& directory);
 
 void SetUserPath(const std::string& path = "");
 
+void SetCurrentRomPath(const std::string& path);
+
 // Returns a pointer to a string with a Citra data dir in the user's home
 // directory. To be used in "multi-user" mode (that is, installed).
 const std::string& GetUserPath(UserPath path);
 
+// Replaces install-specific paths with standard placeholders, and back again
+std::string SerializePath(const std::string& input, bool is_saving);
+
 // Returns the path to where the sys file are
 std::string GetSysDirectory();
 
@@ -318,7 +323,8 @@ private:
 
     template <class Archive>
     void save(Archive& ar, const unsigned int) const {
-        ar << filename;
+        auto s_filename = SerializePath(filename, true);
+        ar << s_filename;
         ar << openmode;
         ar << flags;
         ar << Tell();
@@ -327,6 +333,7 @@ private:
     template <class Archive>
     void load(Archive& ar, const unsigned int) {
         ar >> filename;
+        filename = SerializePath(filename, false);
         ar >> openmode;
         ar >> flags;
         u64 pos;

src/core/core.cpp

@@ -214,6 +214,7 @@ System::ResultStatus System::SingleStep() {
 }
 
 System::ResultStatus System::Load(Frontend::EmuWindow& emu_window, const std::string& filepath) {
+    FileUtil::SetCurrentRomPath(filepath);
     app_loader = Loader::GetLoader(filepath);
     if (!app_loader) {
         LOG_CRITICAL(Core, "Failed to obtain loader for {}!", filepath);