0ad/source/lib/file/common/real_directory.cpp
wraitii 87a2c3347f Make real directory paths on the VFS predictable (retry)
This is the same commit as 4bb31f084e, reverted in 5d1899785a. Noted
issues were fixed.

Partial revert/fix of 2f19cf86d3 and 2567fee329.

Before this diff, it was possible for a mod containing a cache/ or a
config/ folder to get written to incorrectly.
The issue is VFS can map multiple directories to one 'virtual' path, for
reading mods. However, writing data is problematic: which path to
choose?
The only viable solution is to use a path relative to the highest
priority directory encountered in the VFS path, or write paths could be
'hijacked' by lower-priority mods.

This fixes these issues by:
- Adding a new lookup mode ('Real-path') that explicitly picks the real
path relative to the highest-priority subdirectory in the VFS Path.
- Preventing overwriting a real directory with a lower priority one in
general.
- Revert c0c8132dd4's GetRealPath change, re-introducing the function as
GetOriginalPath.

This also cleans up some duplication that led to empty mod folders in
the user mod path, and cleans up loading the 'user' mod.
It also makes it explicit that a directory must be passed to Mount().

Note that the new 'realpath' lookup can still be somewhat complex with
many mount points at various hierarchy levels, but it is at least
predictable/deterministic without having to be careful about populating
order.

Fixes #2553

Differential Revision: https://code.wildfiregames.com/D3728
This was SVN commit r25107.
2021-03-23 12:46:59 +00:00

73 lines
2.2 KiB
C++

/* Copyright (C) 2021 Wildfire Games.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include "precompiled.h"
#include "lib/file/common/real_directory.h"
#include "lib/sysdep/filesystem.h"
#include "lib/file/file.h"
#include "lib/file/io/io.h"
RealDirectory::RealDirectory(const OsPath& path, size_t priority, size_t flags)
: m_path(path), m_priority(priority), m_flags(flags)
{
ENSURE(path.IsDirectory());
}
/*virtual*/ size_t RealDirectory::Precedence() const
{
return 1u;
}
/*virtual*/ wchar_t RealDirectory::LocationCode() const
{
return 'F';
}
/*virtual*/ Status RealDirectory::Load(const OsPath& name, const shared_ptr<u8>& buf, size_t size) const
{
return io::Load(m_path / name, buf.get(), size);
}
Status RealDirectory::Store(const OsPath& name, const shared_ptr<u8>& fileContents, size_t size)
{
return io::Store(m_path / name, fileContents.get(), size);
}
void RealDirectory::Watch()
{
if(!m_watch)
(void)dir_watch_Add(m_path, m_watch);
}
PRealDirectory CreateRealSubdirectory(const PRealDirectory& realDirectory, const OsPath& subdirectoryName)
{
const OsPath path = realDirectory->Path() / subdirectoryName/"";
return PRealDirectory(new RealDirectory(path, realDirectory->Priority(), realDirectory->Flags()));
}