/*---------------------------------------------------------------------------*/
int
cfs_read(int fd, void *buf, unsigned size)
{
struct file_desc *fdp;
struct file *file;
#if COFFEE_MICRO_LOGS
struct file_header hdr;
struct log_param lp;
unsigned bytes_left;
int r;
#endif
if(!(FD_VALID(fd) && FD_READABLE(fd))) {
return -1;
}
fdp = &coffee_fd_set[fd];
file = fdp->file;
if(fdp->offset + size > file->end) {
size = file->end - fdp->offset;
}
/* If the file is allocated, read directly in the file. */
if(!FILE_MODIFIED(file)) {
COFFEE_READ(buf, size, absolute_offset(file->page, fdp->offset));
fdp->offset += size;
return size;
}
#if COFFEE_MICRO_LOGS
read_header(&hdr, file->page);
/*
* Fill the buffer by copying from the log in first hand, or the
* ordinary file if the page has no log record.
*/
for(bytes_left = size; bytes_left > 0; bytes_left -= r) {
r = -1;
lp.offset = fdp->offset;
lp.buf = buf;
lp.size = bytes_left;
r = read_log_page(&hdr, file->record_count, &lp);
/* Read from the original file if we cannot find the data in the log. */
if(r < 0) {
COFFEE_READ(buf, lp.size, absolute_offset(file->page, fdp->offset));
r = lp.size;
}
fdp->offset += r;
buf = (char *)buf + r;
}
#endif /* COFFEE_MICRO_LOGS */
return size;
}
/*---------------------------------------------------------------------------*/
int
cfs_read(int fd, void *buf, unsigned size)
{
struct file_desc *fdp;
struct file *file;
#if COFFEE_MICRO_LOGS
struct file_header hdr;
struct log_param lp;
unsigned bytes_left;
int r;
#endif
if(!(FD_VALID(fd) && FD_READABLE(fd))) {
return -1;
}
fdp = &coffee_fd_set[fd];
file = fdp->file;
if(fdp->offset + size > file->end) {
size = file->end - fdp->offset;
}
/* If the file is not modified, read directly from the file extent. */
if(!FILE_MODIFIED(file)) {
COFFEE_READ(buf, size, absolute_offset(file->page, fdp->offset));
fdp->offset += size;
return size;
}
#if COFFEE_MICRO_LOGS
read_header(&hdr, file->page);
/*
* Copy the contents of the most recent log record. If there is
* no log record for the file area to read from, we simply read
* from the original file extent.
*/
for(bytes_left = size; bytes_left > 0; bytes_left -= r) {
lp.offset = fdp->offset;
lp.buf = buf;
lp.size = bytes_left;
r = read_log_page(&hdr, file->record_count, &lp);
/* Read from the original file if we cannot find the data in the log. */
if(r < 0) {
COFFEE_READ(buf, lp.size, absolute_offset(file->page, fdp->offset));
r = lp.size;
}
fdp->offset += r;
buf = (char *)buf + r;
}
#endif /* COFFEE_MICRO_LOGS */
return size;
}
/*---------------------------------------------------------------------------*/
int
cfs_read(int fd, void *buf, unsigned size)
{
struct file_header hdr;
struct file_desc *fdp;
struct file *file;
unsigned bytes_left;
int r;
#if COFFEE_MICRO_LOGS
struct log_param lp;
#endif
if(!(FD_VALID(fd) && FD_READABLE(fd))) {
return -1;
}
fdp = &coffee_fd_set[fd];
file = fdp->file;
if(fdp->offset + size > file->end) {
size = file->end - fdp->offset;
}
bytes_left = size;
if(FILE_MODIFIED(file)) {
read_header(&hdr, file->page);
}
/*
* Fill the buffer by copying from the log in first hand, or the
* ordinary file if the page has no log record.
*/
while(bytes_left) {
watchdog_periodic();
r = -1;
#if COFFEE_MICRO_LOGS
if(FILE_MODIFIED(file)) {
lp.offset = fdp->offset;
lp.buf = buf;
lp.size = bytes_left;
r = read_log_page(&hdr, file->record_count, &lp);
}
#endif /* COFFEE_MICRO_LOGS */
/* Read from the original file if we cannot find the data in the log. */
if(r < 0) {
r = bytes_left;
COFFEE_READ(buf, r, absolute_offset(file->page, fdp->offset));
}
bytes_left -= r;
fdp->offset += r;
buf += r;
}
return size;
}
static int
write_log_page(struct file *file, struct log_param *lp)
{
struct file_header hdr;
uint16_t region;
coffee_page_t log_page;
int16_t log_record;
uint16_t log_record_size;
uint16_t log_records;
cfs_offset_t offset;
struct log_param lp_out;
read_header(&hdr, file->page);
adjust_log_config(&hdr, &log_record_size, &log_records);
region = modify_log_buffer(log_record_size, &lp->offset, &lp->size);
log_page = 0;
if(HDR_MODIFIED(hdr)) {
/* A log structure has already been created. */
log_page = hdr.log_page;
log_record = find_next_record(file, log_page, log_records);
if(log_record >= log_records) {
/* The log is full; merge the log. */
PRINTF(("Coffee: Merging the file %s with its log\n", hdr.name));
return merge_log(file->page, 0);
}
} else {
/* Create a log structure. */
log_page = create_log(file, &hdr);
if(log_page == INVALID_PAGE) {
return -1;
}
PRINTF(("Coffee: Created a log structure for file %s at page %u\n",
hdr.name, (unsigned)log_page));
hdr.log_page = log_page;
log_record = 0;
}
{
char copy_buf[log_record_size];
lp_out.offset = offset = region * log_record_size;
lp_out.buf = copy_buf;
lp_out.size = log_record_size;
if((lp->offset > 0 || lp->size != log_record_size) &&
read_log_page(&hdr, log_record, &lp_out) < 0) {
COFFEE_READ(copy_buf, sizeof(copy_buf),
absolute_offset(file->page, offset));
}
memcpy(©_buf[lp->offset], lp->buf, lp->size);
/*
* Write the region number in the region index table.
* The region number is incremented to avoid values of zero.
*/
offset = absolute_offset(log_page, 0);
++region;
COFFEE_WRITE(®ion, sizeof(region),
offset + log_record * sizeof(region));
offset += log_records * sizeof(region);
COFFEE_WRITE(copy_buf, sizeof(copy_buf),
offset + log_record * log_record_size);
file->record_count = log_record + 1;
}
return lp->size;
}