Use struct buffer in gdb_readline_no_editing_callback

gdb/ChangeLog:
2016-03-09  Pedro Alves  <palves@redhat.com>

	* event-top.c: Include buffer.h.
	(gdb_readline_no_editing_callback): Use struct buffer instead
	of xrealloc.

2 files changed, 25 insertions, 20 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index bea8172..881d231 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,11 @@
 2016-03-09  Pedro Alves  <palves@redhat.com>
 
+	* event-top.c: Include buffer.h.
+	(gdb_readline_no_editing_callback): Use struct buffer instead
+	of xrealloc.
+
+2016-03-09  Pedro Alves  <palves@redhat.com>
+
 	* common/buffer.h (buffer_grow_char): New function.
 	* top.c: Include buffer.h.
 	(gdb_readline_no_editing): Rename 'prompt_arg' parameter to
diff --git a/gdb/event-top.c b/gdb/event-top.c
index 722bddf..8857235 100644
--- a/gdb/event-top.c
+++ b/gdb/event-top.c
@@ -37,6 +37,7 @@
 #include "gdbcmd.h"		/* for dont_repeat() */
 #include "annotate.h"
 #include "maint.h"
+#include "buffer.h"
 
 /* readline include files.  */
 #include "readline/readline.h"
@@ -382,7 +383,7 @@ top_level_prompt (void)
   return xstrdup (prompt);
 }
 
-/* When there is an event ready on the stdin file desriptor, instead
+/* When there is an event ready on the stdin file descriptor, instead
    of calling readline directly throught the callback function, or
    instead of calling gdb_readline_no_editing_callback, give gdb a
    chance to detect errors and do something.  */
@@ -678,10 +679,11 @@ gdb_readline_no_editing_callback (gdb_client_data client_data)
 {
   int c;
   char *result;
-  int input_index = 0;
-  int result_size = 80;
+  struct buffer line_buffer;
   static int done_once = 0;
 
+  buffer_init (&line_buffer);
+
   /* Unbuffer the input stream, so that, later on, the calls to fgetc
      fetch only one char at the time from the stream.  The fgetc's will
      get up to the first newline, but there may be more chars in the
@@ -694,8 +696,6 @@ gdb_readline_no_editing_callback (gdb_client_data client_data)
       done_once = 1;
     }
 
-  result = (char *) xmalloc (result_size);
-
   /* We still need the while loop here, even though it would seem
      obvious to invoke gdb_readline_no_editing_callback at every
      character entered.  If not using the readline library, the
@@ -712,32 +712,31 @@ gdb_readline_no_editing_callback (gdb_client_data client_data)
 
       if (c == EOF)
 	{
-	  if (input_index > 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);
+	  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 (buffer_finish (&line_buffer));
 	  (*input_handler) (0);
 	  return;
 	}
 
       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';
+  buffer_grow_char (&line_buffer, '\0');
+  result = buffer_finish (&line_buffer);
   (*input_handler) (result);
 }