forked from 0ad/0ad
janwas
94316413db
also: async routines now fill a control block, instead of returning a handle (that's now done by VFS) This was SVN commit r1001.
169 lines
4.8 KiB
C
Executable File
169 lines
4.8 KiB
C
Executable File
// file layer on top of POSIX.
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// provides streaming support and caching.
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//
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// Copyright (c) 2004 Jan Wassenberg
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//
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// This file is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as
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// published by the Free Software Foundation; either version 2 of the
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// License, or (at your option) any later version.
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//
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// This file is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// General Public License for more details.
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//
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// Contact info:
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// Jan.Wassenberg@stud.uni-karlsruhe.de
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// http://www.stud.uni-karlsruhe.de/~urkt/
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#ifndef FILE_H
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#define FILE_H
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struct File
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{
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#ifdef PARANOIA
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u32 magic;
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#endif
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// keep offset of flags and size members in sync with struct ZFile!
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// it is accessed by VFS and must be the same for both (union).
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// dirty, but necessary because VFile is pushing the HDATA size limit.
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uint flags;
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off_t size;
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u32 fn_hash;
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void* mapping;
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uint map_refs;
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int fd;
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};
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enum
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{
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// write-only access; otherwise, read only
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FILE_WRITE = 0x01,
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// the file's contents aren't cached at a higher level; do so here.
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// we keep the file open (until the cache is "full enough"). if it
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// is loaded, we keep the buffer there to satisfy later loads.
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FILE_CACHE = 0x04,
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// random access hint
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// FILE_RANDOM = 0x08,
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FILE_NO_AIO = 0x10,
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FILE_CACHE_BLOCK = 0x20
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};
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// convert to/from our portable path representation,
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// e.g. for external libraries that require the real filename.
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// note: also removes/adds current directory.
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extern int file_make_native_path(const char* path, char* n_path);
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extern int file_make_portable_path(const char* n_path, char* path);
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// set current directory to rel_path, relative to the path to the executable,
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// which is taken from argv0.
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//
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// example: executable in "$install_dir/system"; desired root dir is
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// "$install_dir/data" => rel_path = "../data".
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//
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// this is necessary because the current directory is unknown at startup
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// (e.g. it isn't set when invoked via batch file), and this is the
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// easiest portable way to find our install directory.
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//
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// can only be called once, by design (see source). rel_path is trusted.
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extern int file_rel_chdir(const char* argv0, const char* rel_path);
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// called for each entry in a directory.
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// name is the complete path (see below); it's a directory iff size < 0.
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typedef int(*FileCB)(const char* const name, const ssize_t size, const uintptr_t user);
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// for all files and dirs in <dir> (but not its subdirs!):
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// call <cb>, passing <user> and the entries's name (not path!)
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extern int file_enum(const char* dir, FileCB cb, uintptr_t user);
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extern int file_stat(const char* path, struct stat*);
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extern int file_open(const char* fn, uint flags, File* f);
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extern int file_close(File* f);
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//
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// memory mapping
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//
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// map the entire file <f> into memory. if already currently mapped,
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// return the previous mapping (reference-counted).
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// output parameters are zeroed on failure.
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//
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// the mapping will be removed (if still open) when its file is closed.
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// however, map/unmap calls should still be paired so that the mapping
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// may be removed when no longer needed.
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//
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// rationale: reference counting is required for zip_map: several
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// Zip "mappings" each reference one ZArchive's actual file mapping.
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// implement it here so that we also get refcounting for normal files.
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extern int file_map(File* f, void*& p, size_t& size);
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// decrement the reference count for the mapping belonging to file <f>.
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// fail if there are no references; remove the mapping if the count reaches 0.
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//
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// the mapping will be removed (if still open) when its file is closed.
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// however, map/unmap calls should still be paired so that the mapping
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// may be removed when no longer needed.
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extern int file_unmap(File* f);
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//
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// async IO
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//
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struct FileIO
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{
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u64 block_id;
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// set by file_start_io when in block-cache mode, otherwise 0.
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aiocb* cb;
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// large (144 bytes) on Linux; cannot store here.
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// allocated in file_start_io.
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size_t padding;
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size_t user_size;
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bool our_buf;
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bool from_cache;
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bool given_to_cache;
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bool return_called;
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};
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extern int file_start_io(File* f, off_t ofs, size_t size, void* buf, FileIO* io);
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// indicates if the given IO has completed.
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// return value: 0 if pending, 1 if complete, < 0 on error.
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extern int file_io_complete(FileIO* io);
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extern int file_wait_io(FileIO* io, void*& p, size_t& size);
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extern int file_discard_io(FileIO* io);
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// return value:
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// < 0: failed; abort transfer.
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// >= 0: bytes output; continue.
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typedef ssize_t(*FileIOCB)(uintptr_t ctx, void* p, size_t size);
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extern ssize_t file_io(File* f, off_t ofs, size_t size, void** p, FileIOCB cb = 0, uintptr_t ctx = 0);
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#endif // #ifndef FILE_H
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