-#include "file.h"
-#include "debug.h"
-#include "lib.h"
-#include "malloc.h"
-#include "directory.h"
-#include "filehdr.h"
-#include "filesys.h"
-
-bool
-file_open (struct file *file, disk_sector_t hdr_sector)
+#include "filesys/file.h"
+#include <debug.h>
+#include "filesys/inode.h"
+#include "threads/malloc.h"
+
+/* An open file. */
+struct file
+ {
+ struct inode *inode; /* File's inode. */
+ off_t pos; /* Current position. */
+ bool deny_write; /* Has file_deny_write() been called? */
+ };
+
+/* Opens a file for the given INODE, of which it takes ownership,
+ and returns the new file. Returns a null pointer if an
+ allocation fails or if INODE is null. */
+struct file *
+file_open (struct inode *inode)
{
- file->hdr = filehdr_read (hdr_sector);
- file->bounce = malloc (DISK_SECTOR_SIZE);
- file->pos = 0;
- if (file->hdr != NULL && file->bounce != NULL)
- return true;
+ struct file *file = calloc (1, sizeof *file);
+ if (inode != NULL && file != NULL)
+ {
+ file->inode = inode;
+ file->pos = 0;
+ file->deny_write = false;
+ return file;
+ }
else
{
- filehdr_destroy (file->hdr);
- free (file->bounce);
- return false;
+ inode_close (inode);
+ free (file);
+ return NULL;
}
}
+/* Opens and returns a new file for the same inode as FILE.
+ Returns a null pointer if unsuccessful. */
+struct file *
+file_reopen (struct file *file)
+{
+ return file_open (inode_reopen (file->inode));
+}
+
+/* Closes FILE. */
void
file_close (struct file *file)
{
- filehdr_destroy (file->hdr);
+ if (file != NULL)
+ {
+ file_allow_write (file);
+ inode_close (file->inode);
+ free (file);
+ }
+}
+
+/* Returns the inode encapsulated by FILE. */
+struct inode *
+file_get_inode (struct file *file)
+{
+ return file->inode;
}
+/* Reads SIZE bytes from FILE into BUFFER,
+ starting at the file's current position.
+ Returns the number of bytes actually read,
+ which may be less than SIZE if end of file is reached.
+ Advances FILE's position by the number of bytes read. */
off_t
file_read (struct file *file, void *buffer, off_t size)
{
- off_t bytes_read = file_read_at (file, buffer, size, file->pos);
+ off_t bytes_read = inode_read_at (file->inode, buffer, size, file->pos);
file->pos += bytes_read;
return bytes_read;
}
+/* Reads SIZE bytes from FILE into BUFFER,
+ starting at offset FILE_OFS in the file.
+ Returns the number of bytes actually read,
+ which may be less than SIZE if end of file is reached.
+ The file's current position is unaffected. */
off_t
-file_read_at (struct file *file, void *buffer_, off_t size,
- off_t file_ofs)
+file_read_at (struct file *file, void *buffer, off_t size, off_t file_ofs)
{
- uint8_t *buffer = buffer_;
- off_t bytes_read = 0;
-
- while (size > 0)
- {
- /* Disk sector to read, starting byte offset within sector. */
- off_t sector_idx = filehdr_byte_to_sector (file->hdr, file_ofs);
- int sector_ofs = file_ofs % DISK_SECTOR_SIZE;
-
- /* Bytes left in file, bytes left in sector, lesser of the two. */
- off_t file_left = filehdr_length (file->hdr) - file_ofs;
- int sector_left = DISK_SECTOR_SIZE - sector_ofs;
- int min_left = file_left < sector_left ? file_left : sector_left;
-
- /* Number of bytes to actually copy out of this sector. */
- int chunk_size = size < min_left ? size : min_left;
- if (chunk_size == 0)
- break;
-
- /* Read sector into bounce buffer, then copy into caller's
- buffer. */
- disk_read (filesys_disk, sector_idx, file->bounce);
- memcpy (buffer + bytes_read, file->bounce + sector_ofs, chunk_size);
-
- /* Advance. */
- size -= chunk_size;
- file_ofs += chunk_size;
- bytes_read += chunk_size;
- }
-
- return bytes_read;
+ return inode_read_at (file->inode, buffer, size, file_ofs);
}
+/* Writes SIZE bytes from BUFFER into FILE,
+ starting at the file's current position.
+ Returns the number of bytes actually written,
+ which may be less than SIZE if end of file is reached.
+ (Normally we'd grow the file in that case, but file growth is
+ not yet implemented.)
+ Advances FILE's position by the number of bytes read. */
off_t
file_write (struct file *file, const void *buffer, off_t size)
{
- off_t bytes_written = file_write_at (file, buffer, size, file->pos);
+ off_t bytes_written = inode_write_at (file->inode, buffer, size, file->pos);
file->pos += bytes_written;
return bytes_written;
}
+/* Writes SIZE bytes from BUFFER into FILE,
+ starting at offset FILE_OFS in the file.
+ Returns the number of bytes actually written,
+ which may be less than SIZE if end of file is reached.
+ (Normally we'd grow the file in that case, but file growth is
+ not yet implemented.)
+ The file's current position is unaffected. */
off_t
-file_write_at (struct file *file, const void *buffer_, off_t size,
+file_write_at (struct file *file, const void *buffer, off_t size,
off_t file_ofs)
{
- const uint8_t *buffer = buffer_;
- off_t bytes_written = 0;
+ return inode_write_at (file->inode, buffer, size, file_ofs);
+}
- while (size > 0)
+/* Prevents write operations on FILE's underlying inode
+ until file_allow_write() is called or FILE is closed. */
+void
+file_deny_write (struct file *file)
+{
+ ASSERT (file != NULL);
+ if (!file->deny_write)
{
- /* Starting byte offset within sector to read. */
- off_t sector_idx = filehdr_byte_to_sector (file->hdr, file_ofs);
- int sector_ofs = file_ofs % DISK_SECTOR_SIZE;
-
- /* Bytes left in file, bytes left in sector, lesser of the two. */
- off_t file_left = filehdr_length (file->hdr) - file_ofs;
- int sector_left = DISK_SECTOR_SIZE - sector_ofs;
- int min_left = file_left < sector_left ? file_left : sector_left;
-
- /* Number of bytes to actually writen into this sector. */
- int chunk_size = size < min_left ? size : min_left;
- if (chunk_size == 0)
- break;
-
- /* If the sector contains data before or after the chunk
- we're writing, then we need to read in the sector
- first. Otherwise we start with a sector of all zeros. */
- if (sector_ofs > 0 || chunk_size < sector_ofs)
- disk_read (filesys_disk, sector_idx, file->bounce);
- else
- memset (file->bounce, 0, DISK_SECTOR_SIZE);
- memcpy (file->bounce + sector_ofs, buffer + bytes_written, chunk_size);
- disk_write (filesys_disk, sector_idx, file->bounce);
-
- /* Advance. */
- size -= chunk_size;
- file_ofs += chunk_size;
- bytes_written += chunk_size;
+ file->deny_write = true;
+ inode_deny_write (file->inode);
}
- free (file->bounce);
+}
- return bytes_written;
+/* Re-enables write operations on FILE's underlying inode.
+ (Writes might still be denied by some other file that has the
+ same inode open.) */
+void
+file_allow_write (struct file *file)
+{
+ ASSERT (file != NULL);
+ if (file->deny_write)
+ {
+ file->deny_write = false;
+ inode_allow_write (file->inode);
+ }
}
+/* Returns the size of FILE in bytes. */
off_t
file_length (struct file *file)
{
ASSERT (file != NULL);
- return filehdr_length (file->hdr);
+ return inode_length (file->inode);
}
+/* Sets the current position in FILE to NEW_POS bytes from the
+ start of the file. */
void
-file_seek (struct file *file, off_t file_ofs)
+file_seek (struct file *file, off_t new_pos)
{
ASSERT (file != NULL);
- ASSERT (file_ofs >= 0);
- file->pos = file_ofs;
+ ASSERT (new_pos >= 0);
+ file->pos = new_pos;
}
+/* Returns the current position in FILE as a byte offset from the
+ start of the file. */
off_t
file_tell (struct file *file)
{
projects / pintos-anon / blobdiff