Change tui_data_item_window::content to be a unique_xmalloc_ptr

This changes tui_data_item_window::content to be a unique_xmalloc_ptr
and fixes up the fallout.  It also removes a parameter from
tui_expand_tabs, as it was only ever given one value.

This also removes some tab-handling code from
tui_data_window::display_registers_from.  Because the content can only
be set by tui_register_format, and because that calls tui_expand_tabs,
it's not possible to see a tab here.

gdb/ChangeLog
2019-08-20  Tom Tromey  <tom@tromey.com>

	* tui/tui-regs.h (struct tui_data_item_window)
	<~tui_data_item_window>: Remove.
	<content>: Now a unique_xmalloc_ptr.
	* tui/tui-regs.c (tui_register_format): Return a
	unique_xmalloc_ptr.
	(tui_get_register): Update.
	(~tui_data_item_window): Remove.
	(tui_data_window::display_registers_from, tui_display_register):
	Update.
	* tui/tui-io.h (tui_expand_tabs): Update.
	* tui/tui-io.c (tui_expand_tabs): Return a unique_xmalloc_ptr.
	Remove "col" parameter.

gdb/ChangeLog

@@ -1,3 +1,18 @@
+2019-08-20  Tom Tromey  <tom@tromey.com>
+
+	* tui/tui-regs.h (struct tui_data_item_window)
+	<~tui_data_item_window>: Remove.
+	<content>: Now a unique_xmalloc_ptr.
+	* tui/tui-regs.c (tui_register_format): Return a
+	unique_xmalloc_ptr.
+	(tui_get_register): Update.
+	(~tui_data_item_window): Remove.
+	(tui_data_window::display_registers_from, tui_display_register):
+	Update.
+	* tui/tui-io.h (tui_expand_tabs): Update.
+	* tui/tui-io.c (tui_expand_tabs): Return a unique_xmalloc_ptr.
+	Remove "col" parameter.
+
 2019-08-20  Tom Tromey  <tom@tromey.com>
 
 	* tui/tui-regs.h (struct tui_data_item_window) <value>: Remove

gdb/tui/tui-io.c

@@ -1050,19 +1050,17 @@ tui_getc (FILE *fp)
   return ch;
 }
 
-/* Utility function to expand TABs in a STRING into spaces.  STRING
+/* See tui-io.h.  */
-   will be displayed starting at column COL, and is assumed to include
-   no newlines.  The returned expanded string is malloc'ed.  */
 
-char *
+gdb::unique_xmalloc_ptr<char>
-tui_expand_tabs (const char *string, int col)
+tui_expand_tabs (const char *string)
 {
   int n_adjust, ncol;
   const char *s;
   char *ret, *q;
 
   /* 1. How many additional characters do we need?  */
-  for (ncol = col, n_adjust = 0, s = string; s; )
+  for (ncol = 0, n_adjust = 0, s = string; s; )
     {
       s = strpbrk (s, "\t");
       if (s)
@@ -1079,7 +1077,7 @@ tui_expand_tabs (const char *string, int col)
   ret = q = (char *) xmalloc (strlen (string) + n_adjust + 1);
 
   /* 2. Copy the original string while replacing TABs with spaces.  */
-  for (ncol = col, s = string; s; )
+  for (ncol = 0, s = string; s; )
     {
       const char *s1 = strpbrk (s, "\t");
       if (s1)
@@ -1101,5 +1099,5 @@ tui_expand_tabs (const char *string, int col)
       s = s1;
     }
 
-  return ret;
+  return gdb::unique_xmalloc_ptr<char> (ret);
 }

gdb/tui/tui-io.h

@@ -46,7 +46,7 @@ extern void tui_initialize_io (void);
 extern void tui_redisplay_readline (void);
 
 /* Expand TABs into spaces.  */
-extern char *tui_expand_tabs (const char *, int);
+extern gdb::unique_xmalloc_ptr<char> tui_expand_tabs (const char *);
 
 /* Enter/leave reverse video mode.  */
 extern void tui_set_reverse_mode (WINDOW *w, bool reverse);

gdb/tui/tui-regs.c

@@ -52,7 +52,7 @@ static void tui_show_register_group (tui_data_window *win_info,
 /* Get the register from the frame and return a printable
    representation of it.  */
 
-static char *
+static gdb::unique_xmalloc_ptr<char>
 tui_register_format (struct frame_info *frame, int regnum)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
@@ -72,7 +72,7 @@ tui_register_format (struct frame_info *frame, int regnum)
     str.resize (str.size () - 1);
 
   /* Expand tabs into spaces, since ncurses on MS-Windows doesn't.  */
-  return tui_expand_tabs (str.c_str (), 0);
+  return tui_expand_tabs (str.c_str ());
 }
 
 /* Get the register value from the given frame and format it for the
@@ -87,27 +87,19 @@ tui_get_register (struct frame_info *frame,
     *changedp = false;
   if (target_has_registers)
     {
-      char *prev_content = data->content;
+      gdb::unique_xmalloc_ptr<char> new_content
-
+	= tui_register_format (frame, regnum);
-      data->content = tui_register_format (frame, regnum);
 
       if (changedp != NULL
-	  && strcmp (prev_content, data->content) != 0)
+	  && strcmp (data->content.get (), new_content.get ()) != 0)
 	*changedp = true;
 
-      xfree (prev_content);
+      data->content = std::move (new_content);
     }
 }
 
 /* See tui-regs.h.  */
 
-tui_data_item_window::~tui_data_item_window ()
-{
-  xfree (content);
-}
-
-/* See tui-regs.h.  */
-
 int
 tui_data_window::last_regs_line_no () const
 {
@@ -309,19 +301,13 @@ tui_data_window::display_registers_from (int start_element_no)
       int max_len = 0;
       for (auto &&data_item_win : regs_content)
         {
-          char *p;
+          const char *p;
           int len;
 
           len = 0;
-          p = data_item_win->content;
+          p = data_item_win->content.get ();
           if (p != 0)
-            while (*p)
+	    len = strlen (p);
-              {
-                if (*p++ == '\t')
-                  len = 8 * ((len / 8) + 1);
-                else
-                  len++;
-              }
 
           if (len > max_len)
             max_len = len;
@@ -641,7 +627,7 @@ tui_display_register (struct tui_data_item_window *data)
         waddch (data->handle, ' ');
       wmove (data->handle, 0, 0);
       if (data->content)
-        waddstr (data->handle, data->content);
+        waddstr (data->handle, data->content.get ());
 
       if (data->highlight)
 	/* We ignore the return value, casting it to void in order to avoid

gdb/tui/tui-regs.h

@@ -33,13 +33,11 @@ struct tui_data_item_window : public tui_gen_win_info
   {
   }
 
-  ~tui_data_item_window () override;
-
   const char *name = nullptr;
   /* The register number, or data display number.  */
   int item_no = -1;
   bool highlight = false;
-  char *content = nullptr;
+  gdb::unique_xmalloc_ptr<char> content;
 };
 
 /* The TUI registers window.  */