From ed9ae5a9775d780a6deee0bf7b7be3644a5aad17 Mon Sep 17 00:00:00 2001 From: Lioncash Date: Tue, 18 Aug 2020 14:45:18 -0400 Subject: [PATCH] vfs_real: Avoid redundant map lookups Avoids some trivially avoidable map lookups by keeping the result of find operations around and querying them. --- src/core/file_sys/vfs_real.cpp | 76 ++++++++++++++++++++-------------- 1 file changed, 46 insertions(+), 30 deletions(-) diff --git a/src/core/file_sys/vfs_real.cpp b/src/core/file_sys/vfs_real.cpp index 1dbf632c1..8c6cfcef7 100644 --- a/src/core/file_sys/vfs_real.cpp +++ b/src/core/file_sys/vfs_real.cpp @@ -72,8 +72,10 @@ VfsEntryType RealVfsFilesystem::GetEntryType(std::string_view path_) const { VirtualFile RealVfsFilesystem::OpenFile(std::string_view path_, Mode perms) { const auto path = FS::SanitizePath(path_, FS::DirectorySeparator::PlatformDefault); - if (cache.find(path) != cache.end()) { - auto weak = cache[path]; + + if (const auto weak_iter = cache.find(path); weak_iter != cache.cend()) { + const auto& weak = weak_iter->second; + if (!weak.expired()) { return std::shared_ptr(new RealVfsFile(*this, weak.lock(), path, perms)); } @@ -84,7 +86,7 @@ VirtualFile RealVfsFilesystem::OpenFile(std::string_view path_, Mode perms) { } auto backing = std::make_shared(path, ModeFlagsToString(perms).c_str()); - cache[path] = backing; + cache.insert_or_assign(path, backing); // Cannot use make_shared as RealVfsFile constructor is private return std::shared_ptr(new RealVfsFile(*this, backing, path, perms)); @@ -116,11 +118,12 @@ VirtualFile RealVfsFilesystem::CopyFile(std::string_view old_path_, std::string_ VirtualFile RealVfsFilesystem::MoveFile(std::string_view old_path_, std::string_view new_path_) { const auto old_path = FS::SanitizePath(old_path_, FS::DirectorySeparator::PlatformDefault); const auto new_path = FS::SanitizePath(new_path_, FS::DirectorySeparator::PlatformDefault); + const auto cached_file_iter = cache.find(old_path); - if (cache.find(old_path) != cache.end()) { - auto file = cache[old_path].lock(); + if (cached_file_iter != cache.cend()) { + auto file = cached_file_iter->second.lock(); - if (!cache[old_path].expired()) { + if (!cached_file_iter->second.expired()) { file->Close(); } @@ -131,7 +134,7 @@ VirtualFile RealVfsFilesystem::MoveFile(std::string_view old_path_, std::string_ cache.erase(old_path); file->Open(new_path, "r+b"); - cache[new_path] = file; + cache.insert_or_assign(new_path, std::move(file)); } else { UNREACHABLE(); return nullptr; @@ -142,12 +145,15 @@ VirtualFile RealVfsFilesystem::MoveFile(std::string_view old_path_, std::string_ bool RealVfsFilesystem::DeleteFile(std::string_view path_) { const auto path = FS::SanitizePath(path_, FS::DirectorySeparator::PlatformDefault); - if (cache.find(path) != cache.end()) { - if (!cache[path].expired()) { - cache[path].lock()->Close(); + const auto cached_iter = cache.find(path); + + if (cached_iter != cache.cend()) { + if (!cached_iter->second.expired()) { + cached_iter->second.lock()->Close(); } cache.erase(path); } + return FS::Delete(path); } @@ -192,21 +198,25 @@ VirtualDir RealVfsFilesystem::MoveDirectory(std::string_view old_path_, } for (auto& kv : cache) { - // Path in cache starts with old_path - if (kv.first.rfind(old_path, 0) == 0) { - const auto file_old_path = - FS::SanitizePath(kv.first, FS::DirectorySeparator::PlatformDefault); - const auto file_new_path = - FS::SanitizePath(new_path + DIR_SEP + kv.first.substr(old_path.size()), - FS::DirectorySeparator::PlatformDefault); - auto cached = cache[file_old_path]; - if (!cached.expired()) { - auto file = cached.lock(); - file->Open(file_new_path, "r+b"); - cache.erase(file_old_path); - cache[file_new_path] = file; - } + // If the path in the cache doesn't start with old_path, then bail on this file. + if (kv.first.rfind(old_path, 0) != 0) { + continue; } + + const auto file_old_path = + FS::SanitizePath(kv.first, FS::DirectorySeparator::PlatformDefault); + auto file_new_path = FS::SanitizePath(new_path + DIR_SEP + kv.first.substr(old_path.size()), + FS::DirectorySeparator::PlatformDefault); + const auto& cached = cache[file_old_path]; + + if (cached.expired()) { + continue; + } + + auto file = cached.lock(); + file->Open(file_new_path, "r+b"); + cache.erase(file_old_path); + cache.insert_or_assign(std::move(file_new_path), std::move(file)); } return OpenDirectory(new_path, Mode::ReadWrite); @@ -214,15 +224,21 @@ VirtualDir RealVfsFilesystem::MoveDirectory(std::string_view old_path_, bool RealVfsFilesystem::DeleteDirectory(std::string_view path_) { const auto path = FS::SanitizePath(path_, FS::DirectorySeparator::PlatformDefault); + for (auto& kv : cache) { - // Path in cache starts with old_path - if (kv.first.rfind(path, 0) == 0) { - if (!cache[kv.first].expired()) { - cache[kv.first].lock()->Close(); - } - cache.erase(kv.first); + // If the path in the cache doesn't start with path, then bail on this file. + if (kv.first.rfind(path, 0) != 0) { + continue; } + + const auto& entry = cache[kv.first]; + if (!entry.expired()) { + entry.lock()->Close(); + } + + cache.erase(kv.first); } + return FS::DeleteDirRecursively(path); }