Re: [PATCH] Add fseek to ui-file

[Hui Zhu <teawater@gmail.com>]

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On Fri, Dec 7, 2012 at 5:48 AM, Tom Tromey <tromey@redhat.com> wrote:
>>>>>> "Hui" == Hui Zhu <teawater@gmail.com> writes:
>
> Hui> And stdio_file_fseek has a place different from the other stdio_file
> Hui> functions.  It check the return of fseek.  If it got error, it will
> Hui> throw error.
> Hui> If you think it is OK, I will post patch for other stdio_file functions.
> Hui> If not, it will update this patch.
>
> Thanks.
>
> Hui>  void
> Hui> +set_ui_file_fseek (struct ui_file *file, ui_file_fseek_ftype *fseek)
> Hui> +{
> Hui> +  file->to_fseek = fseek;
>
> I found the argument name 'fseek' confusing here, since this mimics a
> global function of the same name.  Could you rename the argument?

OK.  Fixed.

And I found all other set_ui_file_xxx functions have this issue, do
you mind I post a patch to update them?

>
> Hui> +static void stdio_file_fseek (struct ui_file * file, long offset, int whence)
> Hui> +{
>
> Newline after 'void'.

Fixed.

>
> I wonder whether the null fseek ought to unconditionally throw an
> exception.  It seems to me that it can't really be successful.
>
> I think this should go in conditionally based on the other patches -- no
> need to put it in if it turns out you can't use ui_file after all for
> some reason.
>

I will post another patch for it later.
What about let it throw a internal_error.

> Tom

The attachment is the new patch.  Please help me review it.

Thanks,
Hui

2012-12-07  Hui Zhu  <hui_zhu@mentor.com>

	* ui-file.c (ui_file): Add to_fseek.
	(ui_file_new): Call set_ui_file_fseek.
	(null_file_fseek, ui_file_fseek, set_ui_file_fseek,
	 stdio_file_fseek): New functions.
	(stdio_file_new): Call set_ui_file_fseek.
	* ui-file.h (ui_file_fseek_ftype): New typedef.
	(set_ui_file_fseek, ui_file_fseek): New externs.

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--- a/ui-file.c
+++ b/ui-file.c
@@ -36,6 +36,7 @@ static ui_file_flush_ftype null_file_flu
 static ui_file_delete_ftype null_file_delete;
 static ui_file_rewind_ftype null_file_rewind;
 static ui_file_put_ftype null_file_put;
+static ui_file_fseek_ftype null_file_fseek;
 
 struct ui_file
   {
@@ -49,6 +50,7 @@ struct ui_file
     ui_file_isatty_ftype *to_isatty;
     ui_file_rewind_ftype *to_rewind;
     ui_file_put_ftype *to_put;
+    ui_file_fseek_ftype *to_fseek;
     void *to_data;
   };
 int ui_file_magic;
@@ -68,6 +70,7 @@ ui_file_new (void)
   set_ui_file_isatty (file, null_file_isatty);
   set_ui_file_rewind (file, null_file_rewind);
   set_ui_file_put (file, null_file_put);
+  set_ui_file_fseek (file, null_file_fseek);
   return file;
 }
 
@@ -170,6 +173,12 @@ null_file_delete (struct ui_file *file)
   return;
 }
 
+static void
+null_file_fseek (struct ui_file * stream, long offset, int whence)
+{
+  return;
+}
+
 void *
 ui_file_data (struct ui_file *file)
 {
@@ -228,6 +237,12 @@ ui_file_read (struct ui_file *file, char
 }
 
 void
+ui_file_fseek (struct ui_file * file, long offset, int whence)
+{
+  file->to_fseek (file, offset, whence);
+}
+
+void
 fputs_unfiltered (const char *buf, struct ui_file *file)
 {
   file->to_fputs (buf, file);
@@ -284,6 +299,12 @@ set_ui_file_fputs (struct ui_file *file,
 }
 
 void
+set_ui_file_fseek (struct ui_file *file, ui_file_fseek_ftype *fseek_p)
+{
+  file->to_fseek = fseek_p;
+}
+
+void
 set_ui_file_data (struct ui_file *file, void *data,
 		  ui_file_delete_ftype *delete)
 {
@@ -469,6 +490,7 @@ static ui_file_isatty_ftype stdio_file_i
 static ui_file_delete_ftype stdio_file_delete;
 static struct ui_file *stdio_file_new (FILE *file, int close_p);
 static ui_file_flush_ftype stdio_file_flush;
+static ui_file_fseek_ftype stdio_file_fseek;
 
 static int stdio_file_magic;
 
@@ -499,6 +521,7 @@ stdio_file_new (FILE *file, int close_p)
   set_ui_file_fputs (ui_file, stdio_file_fputs);
   set_ui_file_read (ui_file, stdio_file_read);
   set_ui_file_isatty (ui_file, stdio_file_isatty);
+  set_ui_file_fseek (ui_file, stdio_file_fseek);
   return ui_file;
 }
 
@@ -616,6 +639,19 @@ stdio_file_isatty (struct ui_file *file)
   return (isatty (stdio->fd));
 }
 
+static void
+stdio_file_fseek (struct ui_file * file, long offset, int whence)
+{
+  struct stdio_file *stdio = ui_file_data (file);
+
+  if (stdio->magic != &stdio_file_magic)
+    internal_error (__FILE__, __LINE__,
+		    _("stdio_file_fseek: bad magic number"));
+
+  if (fseek (stdio->file, offset, whence))
+    error (_("fseek fail: %s"), safe_strerror (errno));
+}
+
 /* Like fdopen().  Create a ui_file from a previously opened FILE.  */
 
 struct ui_file *
--- a/ui-file.h
+++ b/ui-file.h
@@ -79,6 +79,11 @@ typedef void (ui_file_delete_ftype) (str
 extern void set_ui_file_data (struct ui_file *stream, void *data,
 			      ui_file_delete_ftype *delete);
 
+typedef void (ui_file_fseek_ftype) (struct ui_file * stream, long offset,
+				    int whence);
+extern void set_ui_file_fseek (struct ui_file *stream,
+			       ui_file_fseek_ftype *fseek);
+
 extern void *ui_file_data (struct ui_file *file);
 
 
@@ -113,6 +118,8 @@ extern char *ui_file_obsavestring (struc
 
 extern long ui_file_read (struct ui_file *file, char *buf, long length_buf);
 
+extern void ui_file_fseek (struct ui_file * file, long offset, int whence);
+
 /* Create/open a memory based file.  Can be used as a scratch buffer
    for collecting output.  */
 extern struct ui_file *mem_fileopen (void);