From 5261efa901dc224d50b884b6f4e81b0178f21354 Mon Sep 17 00:00:00 2001
From: Takoroka <137927095+Takoroka@users.noreply.github.com>
Date: Sun, 1 Nov 2026 12:18:13 -0500
Subject: file_sys: don't let a RomFS build's nodes own each other

Each directory owned its parent and its children, and each file its
parent, so the whole tree of every build kept itself alive after the
build was done. Title 1's loose RomFS (206k files) left ~45 MiB per
build. The context's lists own the nodes; the links between them are
plain pointers.
---
 src/core/file_sys/fsmitm_romfsbuild.cpp | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

(limited to 'src/core/file_sys/fsmitm_romfsbuild.cpp')

diff --git a/src/core/file_sys/fsmitm_romfsbuild.cpp b/src/core/file_sys/fsmitm_romfsbuild.cpp
index 8807bbd0f7..d34e24f177 100644
--- a/src/core/file_sys/fsmitm_romfsbuild.cpp
+++ b/src/core/file_sys/fsmitm_romfsbuild.cpp
@@ -55,15 +55,18 @@ static_assert(sizeof(RomFSFileEntry) == 0x20, "RomFSFileEntry has incorrect size
 
 struct RomFSBuildFileContext;
 
+// The context's directories and files own the nodes; the links between them don't, or every
+// parent and child would own each other and no build would ever be freed (title 1's loose RomFS:
+// 206k files, ~50 MiB per build).
 struct RomFSBuildDirectoryContext {
     std::string path;
     u32 cur_path_ofs = 0;
     u32 path_len = 0;
     u32 entry_offset = 0;
-    std::shared_ptr<RomFSBuildDirectoryContext> parent;
-    std::shared_ptr<RomFSBuildDirectoryContext> child;
-    std::shared_ptr<RomFSBuildDirectoryContext> sibling;
-    std::shared_ptr<RomFSBuildFileContext> file;
+    RomFSBuildDirectoryContext* parent = nullptr;
+    RomFSBuildDirectoryContext* child = nullptr;
+    RomFSBuildDirectoryContext* sibling = nullptr;
+    RomFSBuildFileContext* file = nullptr;
 };
 
 struct RomFSBuildFileContext {
@@ -73,8 +76,8 @@ struct RomFSBuildFileContext {
     u32 entry_offset = 0;
     u64 offset = 0;
     u64 size = 0;
-    std::shared_ptr<RomFSBuildDirectoryContext> parent;
-    std::shared_ptr<RomFSBuildFileContext> sibling;
+    RomFSBuildDirectoryContext* parent = nullptr;
+    RomFSBuildFileContext* sibling = nullptr;
     VirtualFile source;
 };
 
@@ -168,7 +171,7 @@ bool RomFSBuildContext::AddDirectory(std::shared_ptr<RomFSBuildDirectoryContext>
     num_dirs++;
     dir_table_size +=
         sizeof(RomFSDirectoryEntry) + Common::AlignUp(dir_ctx->path_len - dir_ctx->cur_path_ofs, 4);
-    dir_ctx->parent = std::move(parent_dir_ctx);
+    dir_ctx->parent = parent_dir_ctx.get();
     directories.emplace_back(std::move(dir_ctx));
 
     return true;
@@ -180,7 +183,7 @@ bool RomFSBuildContext::AddFile(std::shared_ptr<RomFSBuildDirectoryContext> pare
     num_files++;
     file_table_size +=
         sizeof(RomFSFileEntry) + Common::AlignUp(file_ctx->path_len - file_ctx->cur_path_ofs, 4);
-    file_ctx->parent = std::move(parent_dir_ctx);
+    file_ctx->parent = parent_dir_ctx.get();
     files.emplace_back(std::move(file_ctx));
 
     return true;
@@ -245,11 +248,11 @@ std::vector<std::pair<u64, VirtualFile>> RomFSBuildContext::Build() {
                              Common::AlignUp(cur_file->path_len - cur_file->cur_path_ofs, 4));
         prev_file = cur_file;
     }
-    // Assign deferred parent/sibling ownership.
+    // Assign deferred parent/sibling links.
     for (auto it = files.rbegin(); it != files.rend(); ++it) {
         auto& cur_file = *it;
         cur_file->sibling = cur_file->parent->file;
-        cur_file->parent->file = cur_file;
+        cur_file->parent->file = cur_file.get();
     }
 
     // Determine directory offsets.
@@ -260,11 +263,11 @@ std::vector<std::pair<u64, VirtualFile>> RomFSBuildContext::Build() {
             static_cast<u32>(sizeof(RomFSDirectoryEntry) +
                              Common::AlignUp(cur_dir->path_len - cur_dir->cur_path_ofs, 4));
     }
-    // Assign deferred parent/sibling ownership.
+    // Assign deferred parent/sibling links.
     for (auto it = directories.rbegin(); (*it) != root; ++it) {
         auto& cur_dir = *it;
         cur_dir->sibling = cur_dir->parent->child;
-        cur_dir->parent->child = cur_dir;
+        cur_dir->parent->child = cur_dir.get();
     }
 
     // Create output map.
-- 
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