bug#8370: RFC: cp --no-preserve=contents

[Pádraig Brady]

On 04/12/2012 04:02 PM, Paul Eggert wrote:
> I like this idea too.  Some comments:
> 
>>  Preserve the specified attributes of the original files in the copy,
>> -but do not copy any data.  See the @option{--preserve} option for
>> -controlling which attributes to copy.
>> +but do not copy any data.  Data in existing destination files is not
>> +truncated.  See the @option{--preserve} option for controlling which
>> +attributes to copy.
> 
> The word "data" is plural.  But there is no need to talk about
> truncation: the point is that the file's contents aren't changed at
> all.  Something like this, maybe?
> 
>   Copy only the specified attributes of the source file to the destination.
>   If the destination already exists, do not alter its contents.
>   See the @option{--preserve} option for controlling which attributes to copy.
> 
> 
>> -      dest_desc = open (dst_name, O_WRONLY | O_TRUNC | O_BINARY);
>> +      /* We don't truncate with --attributes-only to support
>> +         copying attributes to an existing file.  */
>> +      dest_desc = open (dst_name, O_WRONLY | O_BINARY
>> +                        | (x->data_copy_required ? O_TRUNC : 0));
> 
> The indentation of the flags expression isn't right, and the
> comment is unnecessary clutter (the code is clear).  Perhaps something
> like this instead?
> 
>      int open_flags =
>        O_WRONLY | O_BINARY | (x->data_copy_required ? O_TRUNC : 0);
>      dest_desc = open (dst_name, open_flags);
> 

Cool.

thanks for the review,
Pádraig.