copymove.c

zgv-5.6,一个Linux系统下的图片浏览器(VGA/SVGA)

/* Zgv v3.1 - GIF, JPEG and PBM/PGM/PPM viewer, for VGA PCs running Linux.
 * Copyright (C) 1993-1998 Russell Marks. See README for license details.
 *
 * copymove.c - guts of the code related to copying/moving files in
 *	the file selector.
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <utime.h>
#include <errno.h>
#include <vga.h>
#include "3deffects.h"
#include "font.h"
#include "readnbkey.h"
#include "zgv.h"
#include "copymove.h"

#define TRANSFER_BUF_SIZE	8192



static int cm_isdir(char *filename)
{
struct stat sbuf;

return(stat(filename,&sbuf)!=-1 && S_ISDIR(sbuf.st_mode));
}


/* copy file, returns 0 if failed
 * src must be in the current directory (though this isn't checked)
 * and dstdir must be a directory (fails if it isn't)
 */
int copyfile(char *src,char *dstdir)
{
static unsigned char copybuf[TRANSFER_BUF_SIZE];
FILE *in,*out;
char *dst;
int siz;

if(!cm_isdir(dstdir)) return(0);

if((in=fopen(src,"rb"))==NULL)
  return(0);

if((dst=malloc(strlen(dstdir)+strlen(src)+2))==NULL)	/* +2 for / and NUL */
  return(0);

strcpy(dst,dstdir);
strcat(dst,"/");
strcat(dst,src);

/* check it doesn't already exist */
if((out=fopen(dst,"rb"))!=NULL)
  {
  fclose(out);
  fclose(in);
  free(dst);
  return(0);
  }

if((out=fopen(dst,"wb"))==NULL)
  {
  fclose(in);
  free(dst);
  return(0);
  }

free(dst);

/* so now both files are open.
 * copy from file to file, up to TRANSFER_BUF_SIZE bytes at a time.
 */

while((siz=fread(copybuf,1,TRANSFER_BUF_SIZE,in))>0)
  {
  if(fwrite(copybuf,1,siz,out)!=siz)
    {
    fclose(out);
    fclose(in);
    return(0);
    }
  }

fclose(out);
fclose(in);
return(1);
}


/* move file, returns 0 if failed
 * src must be in the current directory (though this isn't checked)
 * and dstdir must be a directory (fails if it isn't)
 */
int movefile(char *src,char *dstdir)
{
struct stat sbuf;
struct utimbuf utbuf;
char *dst;

if(!cm_isdir(dstdir)) return(0);

if((dst=malloc(strlen(dstdir)+strlen(src)+2))==NULL)	/* +2 for / and NUL */
  return(0);

strcpy(dst,dstdir);
strcat(dst,"/");
strcat(dst,src);

/* fail if dest file already exists */
if(stat(dst,&sbuf)==0)
  {
  free(dst);
  return(0);
  }

/* first try a rename() */
if(rename(src,dst)==0)
  {
  /* it worked */
  free(dst);
  return(1);
  }

if(errno!=EXDEV)
  {
  /* if the reason it failed wasn't because it couldn't `rename'
   * between filesystems, we should fail too.
   */
  free(dst);
  return(0);
  }

/* resort to copying then deleting */

if(!copyfile(src,dstdir))
  {
  free(dst);
  return(0);
  }

/* try to copy file times/owner/group/perms.
 * I don't consider this important enough to give an error if
 * it screws up (esp. 'cos setting owner might in some cases screw up
 * quite reasonably if we're not root :-)), but it's worth doing I
 * think - not least for consistency with the case where rename() works
 * (where everything is preserved).
 */
if(stat(src,&sbuf)==0)
  {
  /* set times */
  utbuf.actime=sbuf.st_atime;
  utbuf.modtime=sbuf.st_mtime;
  utime(dst,&utbuf);	/* don't much care if it fails */
  
  /* set owner/group and perms - these don't change the times set above */
  chown(dst,sbuf.st_uid,sbuf.st_gid);
  chmod(dst,sbuf.st_mode);
  /* again, not too bothered if they fail */
  }

/* the copy worked, delete the original */
if(remove(src)==0)
  {
  /* the delete worked, all done */
  free(dst);
  return(1);
  }

/* if we couldn't delete the original, delete the copy instead,
 * because the overall move failed and it would be messy to leave
 * it there. However, we're not really that bothered if *this*
 * delete fails. :-)
 */
remove(dst);

free(dst);
return(0);
}