Re: [PATCH 07/10] Use struct buffer in gdb_readline_no_editing

[Sergio Durigan Junior <sergiodj at redhat dot com>]

On Thursday, February 18 2016, Pedro Alves wrote:

> gdb/ChangeLog:
> 2016-02-18  Pedro Alves  <palves@redhat.com>
>
> 	* common/buffer.h (buffer_grow_char): New function.
> 	* top.c: Include buffer.h.
> 	(gdb_readline_no_editing): Use struct buffer instead of xrealloc.

I think you also have to mention here that you renamed PROMPT_ARG to
PROMPT on gdb_readline_no_editing.

> ---
>  gdb/common/buffer.h |  8 ++++++++
>  gdb/top.c           | 40 ++++++++++++++++++----------------------
>  2 files changed, 26 insertions(+), 22 deletions(-)
>
> diff --git a/gdb/common/buffer.h b/gdb/common/buffer.h
> index 2a47db4..bad2c3a 100644
> --- a/gdb/common/buffer.h
> +++ b/gdb/common/buffer.h
> @@ -31,6 +31,14 @@ struct buffer
>     accommodate the new data.  */
>  void buffer_grow (struct buffer *buffer, const char *data, size_t size);
>  
> +/* Append CH to the end of BUFFER.  Grows the buffer to accommodate
> +   the new data.  */
> +static inline void
> +buffer_grow_char (struct buffer *buffer, char c)
> +{
> +  buffer_grow (buffer, &c, 1);
> +}

Missing newline between comment and function.

> +
>  /* Release any memory held by BUFFER.  */
>  void buffer_free (struct buffer *buffer);
>  
> diff --git a/gdb/top.c b/gdb/top.c
> index e781cdd..558f943 100644
> --- a/gdb/top.c
> +++ b/gdb/top.c
> @@ -50,6 +50,7 @@
>  #include "maint.h"
>  #include "filenames.h"
>  #include "frame.h"
> +#include "buffer.h"
>  
>  /* readline include files.  */
>  #include "readline/readline.h"
> @@ -603,65 +604,60 @@ prevent_dont_repeat (void)
>  
>  /* Read a line from the stream "instream" without command line editing.
>  
> -   It prints PROMPT_ARG once at the start.
> +   It prints PROMPT once at the start.
>     Action is compatible with "readline", e.g. space for the result is
>     malloc'd and should be freed by the caller.
>  
>     A NULL return means end of file.  */
>  
>  static char *
> -gdb_readline_no_editing (const char *prompt_arg)
> +gdb_readline_no_editing (const char *prompt)
>  {
> -  int c;
> -  char *result;
> -  int input_index = 0;
> -  int result_size = 80;
> +  struct buffer line_buffer;
>  
> -  if (prompt_arg)
> +  buffer_init (&line_buffer);
> +
> +  if (prompt != NULL)
>      {
>        /* Don't use a _filtered function here.  It causes the assumed
>           character position to be off, since the newline we read from
>           the user is not accounted for.  */
> -      fputs_unfiltered (prompt_arg, gdb_stdout);
> +      fputs_unfiltered (prompt, gdb_stdout);
>        gdb_flush (gdb_stdout);
>      }
>  
> -  result = (char *) xmalloc (result_size);
> -
>    while (1)
>      {
> +      int c;
> +
>        /* Read from stdin if we are executing a user defined command.
>           This is the right thing for prompt_for_continue, at least.  */
>        c = fgetc (instream ? instream : stdin);
>  
>        if (c == EOF)
>  	{
> -	  if (input_index > 0)
> +	  if (line_buffer.used_size > 0)
>  	    /* The last line does not end with a newline.  Return it, and
>  	       if we are called again fgetc will still return EOF and
>  	       we'll return NULL then.  */
>  	    break;
> -	  xfree (result);
> +	  xfree (buffer_finish (&line_buffer));
>  	  return NULL;
>  	}
>  
>        if (c == '\n')
>  	{
> -	  if (input_index > 0 && result[input_index - 1] == '\r')
> -	    input_index--;
> +	  if (line_buffer.used_size > 0
> +	      && line_buffer.buffer[line_buffer.used_size - 1] == '\r')
> +	    line_buffer.used_size--;
>  	  break;
>  	}
>  
> -      result[input_index++] = c;
> -      while (input_index >= result_size)
> -	{
> -	  result_size *= 2;
> -	  result = (char *) xrealloc (result, result_size);
> -	}
> +      buffer_grow_char (&line_buffer, c);
>      }
>  
> -  result[input_index++] = '\0';
> -  return result;
> +  buffer_grow_char (&line_buffer, '\0');
> +  return buffer_finish (&line_buffer);
>  }
>  
>  /* Variables which control command line editing and history
> -- 
> 1.9.3

LGTM after addressing the comments.

Thanks,

-- 
Sergio
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