X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Ffilesys%2Ffile.c;h=27e907feabe36b689d40bf85ae0d865cdc5deef9;hb=07ee003af55dc3aab779e95ef2a4f095f6b65964;hp=e16ff5fc695630cc55b4571f36d27a9d1f3e3fbb;hpb=621963e2a383d53b2c5eca627102625421b46545;p=pintos-anon

diff --git a/src/filesys/file.c b/src/filesys/file.c
index e16ff5f..27e907f 100644
--- a/src/filesys/file.c
+++ b/src/filesys/file.c
@@ -1,33 +1,57 @@
-#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_no hdr_sector) 
+#include "filesys/file.h"
+#include <debug.h>
+#include <string.h>
+#include "filesys/directory.h"
+#include "filesys/inode.h"
+#include "filesys/filesys.h"
+#include "threads/malloc.h"
+
+/* An open file. */
+struct file 
+  {
+    struct inode *inode;        /* File's inode. */
+    uint8_t *bounce;            /* Bounce buffer for reads and writes. */
+    off_t pos;                  /* Current position. */
+  };
+
+/* Opens and returns the file whose inode is in sector
+   INODE_SECTOR.  Returns a null pointer if unsuccessful. */
+struct file *
+file_open (disk_sector_t inode_sector) 
 {
-  file->hdr = filehdr_read (hdr_sector);
+  struct file *file = calloc (1, sizeof *file);
+  if (file == NULL)
+    return NULL;
+  
+  file->inode = inode_open (inode_sector);
   file->bounce = malloc (DISK_SECTOR_SIZE);
   file->pos = 0;
-  if (file->hdr != NULL && file->bounce != NULL)
-    return true;
-  else
+  if (file->inode == NULL || file->bounce == NULL)
     {
-      filehdr_destroy (file->hdr);
+      inode_close (file->inode);
       free (file->bounce);
-      return false;
+      return NULL;
     }
+
+  return file;
 }
 
+/* Closes FILE. */
 void
 file_close (struct file *file) 
 {
-  filehdr_destroy (file->hdr);
+  if (file == NULL)
+    return;
+  
+  inode_close (file->inode);
+  free (file->bounce);
 }
 
+/* Reads SIZE bytes from FILE into BUFFER,
+   starting at the file's current position,
+   and advances the current position.
+   Returns the number of bytes actually read,
+   which may be less than SIZE if end of file is reached. */
 off_t
 file_read (struct file *file, void *buffer, off_t size) 
 {
@@ -36,6 +60,11 @@ file_read (struct file *file, void *buffer, off_t size)
   return bytes_read;
 }
 
+/* Reads SIZE bytes from FILE into BUFFER,
+   starting at offset FILE_OFS in the file.
+   The file's current position is unaffected
+   Returns the number of bytes actually read,
+   which may be less than SIZE if end of file is reached. */
 off_t
 file_read_at (struct file *file, void *buffer_, off_t size,
               off_t file_ofs) 
@@ -46,21 +75,22 @@ file_read_at (struct file *file, void *buffer_, off_t size,
   while (size > 0) 
     {
       /* Disk sector to read, starting byte offset within sector. */
-      off_t sector_idx = filehdr_byte_to_sector (file->hdr, file_ofs);
+      disk_sector_t sector_idx;
       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;
+      off_t file_left = inode_length (file->inode) - 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)
+      if (chunk_size <= 0)
         break;
 
       /* Read sector into bounce buffer, then copy into caller's
          buffer. */
+      sector_idx = inode_byte_to_sector (file->inode, file_ofs);
       disk_read (filesys_disk, sector_idx, file->bounce);
       memcpy (buffer + bytes_read, file->bounce + sector_ofs, chunk_size);
 
@@ -73,6 +103,13 @@ file_read_at (struct file *file, void *buffer_, off_t size,
   return bytes_read;
 }
 
+/* Writes SIZE bytes from BUFFER into FILE,
+   starting at the file's current position,
+   and advances the 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.) */
 off_t
 file_write (struct file *file, const void *buffer, off_t size) 
 {
@@ -81,6 +118,13 @@ file_write (struct file *file, const void *buffer, off_t size)
   return bytes_written;
 }
 
+/* Writes SIZE bytes from BUFFER into FILE,
+   starting at offset FILE_OFS in the file.
+   The file's current position is unaffected
+   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.) */
 off_t
 file_write_at (struct file *file, const void *buffer_, off_t size,
                off_t file_ofs) 
@@ -90,24 +134,25 @@ file_write_at (struct file *file, const void *buffer_, off_t size,
 
   while (size > 0) 
     {
-      /* Starting byte offset within sector to read. */
-      off_t sector_idx = filehdr_byte_to_sector (file->hdr, file_ofs);
+      /* Sector to write, starting byte offset within sector. */
+      off_t sector_idx;
       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;
+      off_t file_left = inode_length (file->inode) - 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. */
+      /* Number of bytes to actually write into this sector. */
       int chunk_size = size < min_left ? size : min_left;
-      if (chunk_size == 0)
+      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)
+      sector_idx = inode_byte_to_sector (file->inode, file_ofs);
+      if (sector_ofs > 0 || chunk_size < sector_left)
         disk_read (filesys_disk, sector_idx, file->bounce);
       else
         memset (file->bounce, 0, DISK_SECTOR_SIZE);
@@ -119,18 +164,20 @@ file_write_at (struct file *file, const void *buffer_, off_t size,
       file_ofs += chunk_size;
       bytes_written += chunk_size;
     }
-  free (file->bounce);
 
   return bytes_written;
 }
 
+/* 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 an offset of FILE_OFS
+   bytes from the start of the file. */
 void
 file_seek (struct file *file, off_t file_ofs) 
 {
@@ -139,6 +186,8 @@ file_seek (struct file *file, off_t file_ofs)
   file->pos = file_ofs;
 }
 
+/* Returns the current position in FILE as a byte offset from the
+   start of the file. */
 off_t
 file_tell (struct file *file) 
 {