372 lines
8 KiB
C++
372 lines
8 KiB
C++
/******************************************************************************
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COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2011.
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This file is part of Sortix.
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Sortix is free software: you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along
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with Sortix. If not, see <http://www.gnu.org/licenses/>.
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fs/ramfs.h
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A filesystem stored entirely in RAM.
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******************************************************************************/
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#include <sortix/kernel/platform.h>
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#include <libmaxsi/error.h>
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#include <libmaxsi/string.h>
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#include <libmaxsi/memory.h>
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#include "../filesystem.h"
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#include "../directory.h"
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#include "../stream.h"
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#include "ramfs.h"
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using namespace Maxsi;
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namespace Sortix
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{
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class DevRAMFSFile : public DevBuffer
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{
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public:
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typedef DevBuffer BaseClass;
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public:
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// Transfers ownership of name.
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DevRAMFSFile(char* name);
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virtual ~DevRAMFSFile();
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public:
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char* name;
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private:
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size_t offset;
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byte* buffer;
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size_t bufferused;
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size_t buffersize;
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public:
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virtual size_t BlockSize();
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virtual uintmax_t Size();
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virtual uintmax_t Position();
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virtual bool Seek(uintmax_t position);
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virtual bool Resize(uintmax_t size);
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virtual ssize_t Read(byte* dest, size_t count);
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virtual ssize_t Write(const byte* src, size_t count);
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virtual bool IsReadable();
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virtual bool IsWritable();
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};
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DevRAMFSFile::DevRAMFSFile(char* name)
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{
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this->name = name;
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buffer = NULL;
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bufferused = 0;
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buffersize = 0;
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}
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DevRAMFSFile::~DevRAMFSFile()
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{
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delete[] name;
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delete[] buffer;
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}
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size_t DevRAMFSFile::BlockSize()
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{
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return 1;
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}
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uintmax_t DevRAMFSFile::Size()
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{
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return bufferused;
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}
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uintmax_t DevRAMFSFile::Position()
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{
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return offset;
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}
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bool DevRAMFSFile::Seek(uintmax_t position)
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{
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if ( SIZE_MAX < position ) { Error::Set(EOVERFLOW); return false; }
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offset = position;
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return true;
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}
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bool DevRAMFSFile::Resize(uintmax_t size)
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{
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if ( SIZE_MAX < size ) { Error::Set(EOVERFLOW); return false; }
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byte* newbuffer = new byte[size];
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if ( !newbuffer ) { Error::Set(ENOSPC); return false; }
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size_t sharedmemsize = ( size < bufferused ) ? size : bufferused;
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Memory::Copy(newbuffer, buffer, sharedmemsize);
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delete[] buffer;
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buffer = newbuffer;
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bufferused = sharedmemsize;
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buffersize = size;
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return true;
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}
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ssize_t DevRAMFSFile::Read(byte* dest, size_t count)
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{
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if ( SSIZE_MAX < count ) { count = SSIZE_MAX; }
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size_t available = count;
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if ( bufferused < offset + count ) { available = bufferused - offset; }
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if ( available == 0 ) { return 0; }
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Memory::Copy(dest, buffer + offset, available);
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offset += available;
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return available;
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}
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ssize_t DevRAMFSFile::Write(const byte* src, size_t count)
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{
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if ( SSIZE_MAX < count ) { count = SSIZE_MAX; }
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if ( buffersize < offset + count )
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{
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uintmax_t newsize = (uintmax_t) offset + (uintmax_t) count;
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if ( newsize < buffersize * 2 ) { newsize = buffersize * 2; }
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if ( !Resize(newsize) ) { return -1; }
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}
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Memory::Copy(buffer + offset, src, count);
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offset += count;
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if ( bufferused < offset ) { bufferused = offset; }
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return count;
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}
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bool DevRAMFSFile::IsReadable()
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{
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return true;
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}
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bool DevRAMFSFile::IsWritable()
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{
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return true;
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}
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DevRAMFS::DevRAMFS()
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{
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files = NULL;
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}
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DevRAMFS::~DevRAMFS()
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{
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if ( files )
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{
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while ( !files->Empty() ) { delete files->Remove(0); }
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delete files;
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}
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}
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class DevRAMFSDir : public DevDirectory
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{
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public:
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typedef Device DevDirectory;
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public:
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DevRAMFSDir(DevRAMFS* fs);
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virtual ~DevRAMFSDir();
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private:
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DevRAMFS* fs;
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size_t position;
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public:
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virtual void Rewind();
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virtual int Read(sortix_dirent* dirent, size_t available);
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};
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DevRAMFSDir::DevRAMFSDir(DevRAMFS* fs)
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{
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position = 0;
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this->fs = fs;
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fs->Refer();
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}
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DevRAMFSDir::~DevRAMFSDir()
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{
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fs->Unref();
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}
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void DevRAMFSDir::Rewind()
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{
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position = 0;
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}
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int DevRAMFSDir::Read(sortix_dirent* dirent, size_t available)
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{
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if ( available <= sizeof(sortix_dirent) ) { return -1; }
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if ( fs->GetNumFiles() <= position )
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{
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dirent->d_namelen = 0;
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dirent->d_name[0] = 0;
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return 0;
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}
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const char* name = fs->GetFilename(position);
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if ( !name ) { return -1; }
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size_t namelen = String::Length(name);
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size_t needed = sizeof(sortix_dirent) + namelen + 1;
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if ( available < needed )
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{
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dirent->d_namelen = needed;
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Error::Set(ERANGE);
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return -1;
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}
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Memory::Copy(dirent->d_name, name, namelen + 1);
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dirent->d_namelen = namelen;
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position++;
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return 0;
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}
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int CompareFiles(DevRAMFSFile* file1, DevRAMFSFile* file2)
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{
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return String::Compare(file1->name, file2->name);
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}
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int LookupFile(DevRAMFSFile* file, const char* name)
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{
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return String::Compare(file->name, name);
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}
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Device* DevRAMFS::Open(const char* path, int flags, mode_t mode)
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{
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if ( path[0] == 0 || (path[0] == '/' && path[1] == 0) )
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{
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if ( (flags & O_LOWERFLAGS) == O_SEARCH )
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{
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return new DevRAMFSDir(this);
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}
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Error::Set(EISDIR);
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return NULL;
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}
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if ( (flags & O_LOWERFLAGS) == O_SEARCH ) { Error::Set(ENOTDIR); return NULL; }
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if ( *path++ != '/' ) { Error::Set(ENOENT); return NULL; }
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size_t pathlen = String::Length(path);
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for ( size_t i = 0; i < pathlen; i++ )
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{
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if ( path[i] == '/' ) { Error::Set(ENOENT); return NULL; }
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}
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DevBuffer* file = OpenFile(path, flags, mode);
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if ( !file ) { return NULL; }
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Device* wrapper = new DevFileWrapper(file, flags);
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if ( !wrapper ) { Error::Set(ENOSPC); return NULL; }
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return wrapper;
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}
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DevBuffer* DevRAMFS::OpenFile(const char* path, int flags, mode_t mode)
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{
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// Hack to prevent / from being a filename.
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if ( path == 0 ) { Error::Set(ENOENT); return NULL; }
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if ( files )
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{
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size_t fileindex = files->Search(LookupFile, path);
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if ( fileindex != SIZE_MAX )
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{
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DevRAMFSFile* file = files->Get(fileindex);
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if ( flags & O_TRUNC ) { file->Resize(0); }
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return file;
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}
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}
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return CreateFile(path, flags, mode);
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}
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DevBuffer* DevRAMFS::CreateFile(const char* path, int flags, mode_t mode)
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{
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if ( !(flags & O_CREAT) ) { Error::Set(ENOENT); return NULL; }
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if ( !files )
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{
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files = new SortedList<DevRAMFSFile*>(CompareFiles);
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if ( !files) { Error::Set(ENOSPC); return NULL; }
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}
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if ( files->Search(LookupFile, path) != SIZE_MAX )
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{
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Error::Set(EEXIST);
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return NULL;
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}
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char* newpath = String::Clone(path);
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if ( !newpath ) { Error::Set(ENOSPC); return NULL; }
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DevRAMFSFile* file = new DevRAMFSFile(newpath);
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if ( !file ) { delete[] newpath; Error::Set(ENOSPC); return NULL; }
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if ( !files->Add(file) ) { delete file; Error::Set(ENOSPC); return NULL; }
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file->Refer();
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return file;
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}
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bool DevRAMFS::Unlink(const char* path)
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{
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if ( *path == '\0' || ( *path++ == '/' && *path == '\0' ) )
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{
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Error::Set(EISDIR);
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return false;
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}
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if ( !files ) { Error::Set(ENOENT); return false; }
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size_t index = files->Search(LookupFile, path);
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if ( index == SIZE_MAX ) { Error::Set(ENOENT); return false; }
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Device* dev = files->Remove(index);
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ASSERT(dev);
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dev->Unref();
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return true;
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}
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const bool BINDEVHACK = true;
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size_t DevRAMFS::GetNumFiles()
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{
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size_t result = 2 + (BINDEVHACK ? 2 : 0);
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if ( files ) { result += files->Length(); }
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return result;
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}
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const char* DevRAMFS::GetFilename(size_t index)
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{
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switch ( index )
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{
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case 0: return ".";
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case 1: return "..";
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default: index -= 2;
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}
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if ( BINDEVHACK ) switch ( index )
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{
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case 0: return "bin";
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case 1: return "dev";
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default: index -= 2;
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}
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if ( !files )
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return NULL;
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if ( files->Length() <= index )
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return NULL;
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DevRAMFSFile* file = files->Get(index);
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return file->name;
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}
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}
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