/* returns 0 on success, or an errno on failure */
static int
readOrWriteBytes (tr_session * session,
tr_torrent * tor,
int ioMode,
tr_file_index_t fileIndex,
uint64_t fileOffset,
void * buf,
size_t buflen)
{
int fd;
int err = 0;
const bool doWrite = ioMode >= TR_IO_WRITE;
const tr_info * const info = &tor->info;
const tr_file * const file = &info->files[fileIndex];
assert (fileIndex < info->fileCount);
assert (!file->length || (fileOffset < file->length));
assert (fileOffset + buflen <= file->length);
if (!file->length)
return 0;
/***
**** Find the fd
***/
fd = tr_fdFileGetCached (session, tr_torrentId (tor), fileIndex, doWrite);
if (fd < 0)
{
/* it's not cached, so open/create it now */
char * subpath;
const char * base;
/* see if the file exists... */
if (!tr_torrentFindFile2 (tor, fileIndex, &base, &subpath, NULL))
{
/* we can't read a file that doesn't exist... */
if (!doWrite)
err = ENOENT;
/* figure out where the file should go, so we can create it */
base = tr_torrentGetCurrentDir (tor);
subpath = tr_sessionIsIncompleteFileNamingEnabled (tor->session)
? tr_torrentBuildPartial (tor, fileIndex)
: tr_strdup (file->name);
}
if (!err)
{
/* open (and maybe create) the file */
char * filename = tr_buildPath (base, subpath, NULL);
const int prealloc = file->dnd || !doWrite
? TR_PREALLOCATE_NONE
: tor->session->preallocationMode;
if (((fd = tr_fdFileCheckout (session, tor->uniqueId, fileIndex,
filename, doWrite,
prealloc, file->length))) < 0)
{
err = errno;
tr_torerr (tor, "tr_fdFileCheckout failed for \"%s\": %s",
filename, tr_strerror (err));
}
else if (doWrite)
{
/* make a note that we just created a file */
tr_statsFileCreated (tor->session);
}
tr_free (filename);
}
tr_free (subpath);
}
/***
**** Use the fd
***/
if (!err)
{
if (ioMode == TR_IO_READ)
{
const int rc = tr_pread (fd, buf, buflen, fileOffset);
if (rc < 0)
{
err = errno;
tr_torerr (tor, "read failed for \"%s\": %s", file->name, tr_strerror (err));
}
}
else if (ioMode == TR_IO_WRITE)
{
const int rc = tr_pwrite (fd, buf, buflen, fileOffset);
if (rc < 0)
{
err = errno;
tr_torerr (tor, "write failed for \"%s\": %s", file->name, tr_strerror (err));
}
}
else if (ioMode == TR_IO_PREFETCH)
{
tr_prefetch (fd, fileOffset, buflen);
}
else
{
abort ();
}
}
return err;
}
/* returns 0 on success, or an errno on failure */
static int
readOrWriteBytes( tr_session * session,
tr_torrent * tor,
int ioMode,
tr_file_index_t fileIndex,
uint64_t fileOffset,
void * buf,
size_t buflen )
{
const tr_info * info = &tor->info;
const tr_file * file = &info->files[fileIndex];
int fd = -1;
int err = 0;
const tr_bool doWrite = ioMode >= TR_IO_WRITE;
//if( doWrite )
// fprintf( stderr, "in file %s at offset %zu, writing %zu bytes; file length is %zu\n", file->name, (size_t)fileOffset, buflen, (size_t)file->length );
assert( fileIndex < info->fileCount );
assert( !file->length || ( fileOffset < file->length ) );
assert( fileOffset + buflen <= file->length );
if( !file->length )
return 0;
fd = tr_fdFileGetCached( session, tr_torrentId( tor ), fileIndex, doWrite );
if( fd < 0 )
{
/* the fd cache doesn't have this file...
* we'll need to open it and maybe create it */
char * subpath;
const char * base;
tr_bool fileExists;
tr_preallocation_mode preallocationMode;
fileExists = tr_torrentFindFile2( tor, fileIndex, &base, &subpath );
if( !fileExists )
{
base = tr_torrentGetCurrentDir( tor );
if( tr_sessionIsIncompleteFileNamingEnabled( tor->session ) )
subpath = tr_torrentBuildPartial( tor, fileIndex );
else
subpath = tr_strdup( file->name );
}
if( ( file->dnd ) || ( ioMode < TR_IO_WRITE ) )
preallocationMode = TR_PREALLOCATE_NONE;
else
preallocationMode = tor->session->preallocationMode;
if( ( ioMode < TR_IO_WRITE ) && !fileExists ) /* does file exist? */
{
err = ENOENT;
}
else
{
char * filename = tr_buildPath( base, subpath, NULL );
if( ( fd = tr_fdFileCheckout( session, tor->uniqueId, fileIndex, filename,
doWrite, preallocationMode, file->length ) ) < 0 )
{
err = errno;
tr_torerr( tor, "tr_fdFileCheckout failed for \"%s\": %s", filename, tr_strerror( err ) );
}
tr_free( filename );
}
if( doWrite && !err )
tr_statsFileCreated( tor->session );
tr_free( subpath );
}
if( !err )
{
/* check & see if someone deleted the file while it was in our cache */
struct stat sb;
const tr_bool file_disappeared = fstat( fd, &sb ) || sb.st_nlink < 1;
if( file_disappeared ) {
tr_torrentSetLocalError( tor, "Please Verify Local Data! A file disappeared: \"%s\"", tor->info.files[fileIndex].name );
err = ENOENT;
}
if( ioMode == TR_IO_READ ) {
const int rc = tr_pread( fd, buf, buflen, fileOffset );
if( rc < 0 ) {
err = errno;
tr_torerr( tor, "read failed for \"%s\": %s",
file->name, tr_strerror( err ) );
}
} else if( ioMode == TR_IO_PREFETCH ) {
const int rc = tr_prefetch( fd, fileOffset, buflen );
if( rc < 0 ) {
/* (don't set "err" here... it's okay for prefetch to fail) */
tr_tordbg( tor, "prefetch failed for \"%s\": %s",
file->name, tr_strerror( errno ) );
}
} else if( ioMode == TR_IO_WRITE ) {
const int rc = tr_pwrite( fd, buf, buflen, fileOffset );
if( rc < 0 ) {
err = errno;
tr_torerr( tor, "write failed for \"%s\": %s",
file->name, tr_strerror( err ) );
}
} else {
abort();
}
}
return err;
}