From 7f6002caba3f0a6749820c2772161caf55b8d267 Mon Sep 17 00:00:00 2001 From: neonloop Date: Fri, 7 May 2021 20:00:12 +0000 Subject: Initial commit (uqm-0.8.0) --- src/libs/uio/doc/todo | 144 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 144 insertions(+) create mode 100644 src/libs/uio/doc/todo (limited to 'src/libs/uio/doc/todo') diff --git a/src/libs/uio/doc/todo b/src/libs/uio/doc/todo new file mode 100644 index 0000000..b9f232c --- /dev/null +++ b/src/libs/uio/doc/todo @@ -0,0 +1,144 @@ +Needed for use in UQM: +- documentation +- configuring for GLOB +- when doing uio_getStdioPhysical(), if write access is required, but + not available on the original location, also copy the file to the + temporary dir. +- Call fsync() at appropriate times. + +Documentation: +- use doxygen +- Warning: getting (part of) the contents of a directory is fairly slow, + as dirs need to be merged. +- It would be (theoretically) possible to add HTTP and FTP support for + remote file systems. +- on adding extra file system types: + open, mkdir, rmdir, and unlink should themselves make sure that + the physical structure is kept up to date when an entry is + removed or added. +- stream stuff is not thread safe +- uio_fflush() does not accept NULL as argument to flush all streams, + like stdio fflush() does. +- uio_close() does never fail +- The physical open function should call uio_Handle_new and store its own + data in it. + The physical close function should delete its own data. It's called + Will cleanup the general Handle. + Analogous for mount/unmount with PRoot +- No need to store MountHandles. They will be automatically freed + when the repository is closed. +- You can use mount stuff from other repositories. +- ".." works by nullifying one path component, not by following the ".." link + in the directory. "/a/../b" will always be functionally equivalent to + "/b", even when "/a" is a symlink. + +Testing: +- Test mounting an UNC directory + +Bugs: +- 'openDir(repository, "dir/")' will have the trailing '/' + in the dirHandle, which will cause problems. +- 'openDirRelative(repository, "/")' causes segfaults later on +- uio_rename() doesn't work on directories +- uio_getPhysicalAccess() needs to be changed so that it works the same on + dirs as on files. stat() can be cleaned up too then. +- uio_getPhysicalAccess() will not return ENOENT when (only) the last + component does not exist, even when O_RDONLY is used. + For O_RDRW, O_CREAT should probably be checked too (function description + needs to be updated too then). +- A lot of inlining is not possible because of the order of function + definitions. +- sizeof(size_t) may be less than 4 on some platforms. Check what problems + this may cause. At least the size of zip_INPUT_BUFFER_SIZE is an + issue. SIZE_MAX can be used to check for sizeof(size_t) at runtime. +- remove() is probably more compatible than unlink(). remove() is part + of the C standard (as well as POSIX), unlink() is just POSIX. +- seeking in files opened as "text" on Windows goes wrong. +- Network paths on Windows are not accepted. +- No CRLF translation (and ^Z recognition) is done for files read from + zip files, even though that may be expected on Windows. +- The order in which "uio_unmountAllDirs() unmounts the directories, may lead + it to unmount a dir while there still is a file descriptor for another + dir open, causing a warning. + +Extra features (not necessary for UQM): +- Make functions to use for uio_malloc, uio_free and uio_realloc + configurable at init. +- add uio_mmap() +- add match_MATCH_ALL and match_MATCH_NONE +- automounting + - Unmount automounted filesystems when the originating filesystem + is unmounted. +- when doing stat() on a directory, merge the stat info of the underlying + physical dirs. +- read directory information from zip files. +- implement ungetc() +- make fileblocks public +- setmode() for windows? +- prevent aliasing of files/dirs, both between two physical file + systems (where possible), as within the same filesystem (in particular + stdio). On Windows, aliasing can occur easilly when a file or dir + is accessed with the long vs the short ("PROGRA~1") name, or when + capitalisation is involved. +- accept non-dir, non-regular-file dir entries in stdio. +- Add non-merging mounts. Make 'merging' an option for the mount. +- make uio_rename() work cross-fs, or provide a wrapper which does that. + (the system rename() doesn't work cross-fs either, so keeping uio_rename() + as it is makes sense, as I'm trying to stay close to the system functions, + even though hiding file systems from the user would be nicer) +- Add a readdir_r(). Right now, for Symbian readdir_r() is defined in + uioport.h, but the actual implementation is out of the uio tree. + +Optimisations (not necessary for UQM): +- use mmap for fileBlocks +- Use a pre-allocated pool of hash table entries for allocHashEntry. +- optimise certain strings (specifically directory entries) by making + a string type which has pointers to a shared char array. + Invariant: if two strings are the same, they point to the same + character array. Consequence: string comparison is pointer comparison. + Making a new string would imply checking the existing strings. + Existing strings should be in a hash table. +- optimise paths + Encode all paths internally as (double-linked) chains of path components + This way, operations like going up one path component, are cheap. + Each path component could either be represented by a pointer to a string, + (possibly shared as above), or as a pair of begin and end pointers + (or begin pointer and length). In the latter case, there's no need for + copying strings when parsing a user-supplied string, but sharing of strings + would not be possible. + It's probably possible to use both methods next to eachother; + shared strings for stored paths, and pointers into a path for user-supplied + strings (which would be freed when the call returns). + Instead of a linked list, perhaps an array can be used, as paths rarely + change. It would be a problem if for some reason, recursively path + components are added to a path. +- (maybe) keep track of already issued handles, so that the ref counter + could just be incremented, instead of issuing a new one. + (uio_getPDirEntryHandle) +- Make it possible for people to add their own file system, without giving + away the internals. (no wanton including of .h files) +- Don't cache stdio dir structure + (and don't read the dir leading up to the dir that is actually needed) +- mounting foo to /Foo and foo/bar to /Foo/Bar should result in only one + physical structure. Preferably, it shouldn't even lead to two mountInfo + structures for /Foo/Bar, so that merging the dirs is not unnecessarilly + expensive. +- add uio_access() + (uqm fileExists can be redone then) +- implement the physical function cleanup() to clean up the physical + structure. Int argument that specifies how thoroughly. + On it depends whether cache is cleaned, whether stuff is realloc'ed + to defragment memory, etc. + +Cleanups (not necessary for UQM): +- rename function names to be more like class names for as far as that's + not already done. + uio_PRoot_unref etc +- Add uio_fatal(), uio_error(), uio_warning() +- Clean up the include structure +- use stdint.h and stdbool.h types directly, instead of using uio_int16 etc. + Remove types.h, and instead, if these types are missing on some platforms, + put the fixes in port.h. + + + -- cgit v1.2.3