Use std::string for ui_out_hdr's text fields

This patch makes ui_out_hdr use std::string for its text fields.  It
makes freeing automatic when the object is deleted.

gdb/ChangeLog:

	* mi/mi-out.c (mi_table_header): Change char * args to
	std::string.
	* cli-out.c (cli_table_header): Likewise.
	* ui-out.h (table_header_ftype): Likewise.
	(ui_out_table_header): Constify colhdr argument.
	(ui_out_query_field): Constify col_name argument.
	* ui-out.c (ui_out_hdr) <col_name, colhdr>: Change type to
	std::string.
	(uo_table_header): Change char * args to std::string.
	(ui_out_table_header): Likewise.
	(get_next_header): Constify colhdr argument and adapt.
	(clear_header_list): Don't free col_name/colhdr fields.
	(append_header_to_list): Change char * args to std::string and
	adapt.
	(verify_field): Constify variable.
	(ui_out_query_field): Constify col_name argument and adapt.
	* breakpoint.c (wrap_indent_at_field): Constify variable.

6 files changed, 62 insertions, 53 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index bb7cf1e..15b1b79 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,25 @@
 2016-12-01  Simon Marchi  <simon.marchi@polymtl.ca>
 
+	* mi/mi-out.c (mi_table_header): Change char * args to
+	std::string.
+	* cli-out.c (cli_table_header): Likewise.
+	* ui-out.h (table_header_ftype): Likewise.
+	(ui_out_table_header): Constify colhdr argument.
+	(ui_out_query_field): Constify col_name argument.
+	* ui-out.c (ui_out_hdr) <col_name, colhdr>: Change type to
+	std::string.
+	(uo_table_header): Change char * args to std::string.
+	(ui_out_table_header): Likewise.
+	(get_next_header): Constify colhdr argument and adapt.
+	(clear_header_list): Don't free col_name/colhdr fields.
+	(append_header_to_list): Change char * args to std::string and
+	adapt.
+	(verify_field): Constify variable.
+	(ui_out_query_field): Constify col_name argument and adapt.
+	* breakpoint.c (wrap_indent_at_field): Constify variable.
+
+2016-12-01  Simon Marchi  <simon.marchi@polymtl.ca>
+
 	* ui-out.c (struct ui_out_hdr) <next>: Remove.
 	(struct ui_out_table) <header_first, header_last, header_next>: Remove.
 	<headers, headers_iterator>: New fields.
diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index d737cad..38262ba 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -6062,7 +6062,7 @@ wrap_indent_at_field (struct ui_out *uiout, const char *col_name)
 {
   static char wrap_indent[80];
   int i, total_width, width, align;
-  char *text;
+  const char *text;
 
   total_width = 0;
   for (i = 1; ui_out_query_field (uiout, i, &width, &align, &text); i++)
diff --git a/gdb/cli-out.c b/gdb/cli-out.c
index 093b6e7..4747f40 100644
--- a/gdb/cli-out.c
+++ b/gdb/cli-out.c
@@ -94,8 +94,7 @@ cli_table_end (struct ui_out *uiout)
 
 static void
 cli_table_header (struct ui_out *uiout, int width, enum ui_align alignment,
-		  const char *col_name,
-		  const char *colhdr)
+		  const std::string &col_name, const std::string &col_hdr)
 {
   cli_out_data *data = (cli_out_data *) ui_out_data (uiout);
 
@@ -104,7 +103,7 @@ cli_table_header (struct ui_out *uiout, int width, enum ui_align alignment,
 
   /* Always go through the function pointer (virtual function call).
      We may have been extended.  */
-  uo_field_string (uiout, 0, width, alignment, 0, colhdr);
+  uo_field_string (uiout, 0, width, alignment, 0, col_hdr.c_str ());
 }
 
 /* Mark beginning of a list */
diff --git a/gdb/mi/mi-out.c b/gdb/mi/mi-out.c
index b4da3ba..9a2cb83 100644
--- a/gdb/mi/mi-out.c
+++ b/gdb/mi/mi-out.c
@@ -41,8 +41,9 @@ static void mi_table_begin (struct ui_out *uiout, int nbrofcols,
 static void mi_table_body (struct ui_out *uiout);
 static void mi_table_end (struct ui_out *uiout);
 static void mi_table_header (struct ui_out *uiout, int width,
-			     enum ui_align alig, const char *col_name,
-			     const char *colhdr);
+			     enum ui_align alignment,
+			     const std::string &col_name,
+			     const std::string &col_hdr);
 static void mi_begin (struct ui_out *uiout, enum ui_out_type type,
 		      int level, const char *id);
 static void mi_end (struct ui_out *uiout, enum ui_out_type type, int level);
@@ -140,7 +141,7 @@ mi_table_end (struct ui_out *uiout)
 
 void
 mi_table_header (struct ui_out *uiout, int width, enum ui_align alignment,
-		 const char *col_name, const char *colhdr)
+		 const std::string &col_name, const std::string &col_hdr)
 {
   mi_out_data *data = (mi_out_data *) ui_out_data (uiout);
 
@@ -150,8 +151,8 @@ mi_table_header (struct ui_out *uiout, int width, enum ui_align alignment,
   mi_open (uiout, NULL, ui_out_type_tuple);
   mi_field_int (uiout, 0, 0, ui_center, "width", width);
   mi_field_int (uiout, 0, 0, ui_center, "alignment", alignment);
-  mi_field_string (uiout, 0, 0, ui_center, "col_name", col_name);
-  mi_field_string (uiout, 0, width, alignment, "colhdr", colhdr);
+  mi_field_string (uiout, 0, 0, ui_center, "col_name", col_name.c_str ());
+  mi_field_string (uiout, 0, width, alignment, "colhdr", col_hdr.c_str ());
   mi_close (uiout, ui_out_type_tuple);
 }
 
diff --git a/gdb/ui-out.c b/gdb/ui-out.c
index 8e44698..3cd5695 100644
--- a/gdb/ui-out.c
+++ b/gdb/ui-out.c
@@ -36,8 +36,8 @@ struct ui_out_hdr
     int colno;
     int width;
     enum ui_align alignment;
-    char *col_name;
-    char *colhdr;
+    std::string col_name;
+    std::string col_hdr;
   };
 
 struct ui_out_level
@@ -148,8 +148,9 @@ static void uo_table_begin (struct ui_out *uiout, int nbrofcols,
 static void uo_table_body (struct ui_out *uiout);
 static void uo_table_end (struct ui_out *uiout);
 static void uo_table_header (struct ui_out *uiout, int width,
-			     enum ui_align align, const char *col_name,
-			     const char *colhdr);
+			     enum ui_align align,
+			     const std::string &col_name,
+			     const std::string &col_hdr);
 static void uo_begin (struct ui_out *uiout,
 		      enum ui_out_type type,
 		      int level, const char *id);
@@ -176,10 +177,11 @@ static int uo_redirect (struct ui_out *uiout, struct ui_file *outstream);
 /* Prototypes for local functions */
 
 static void append_header_to_list (struct ui_out *uiout, int width,
-				   enum ui_align alignment, const char *col_name,
-				   const char *colhdr);
+				   enum ui_align alignment,
+				   const std::string &col_name,
+				   const std::string &col_hdr);
 static int get_next_header (struct ui_out *uiout, int *colno, int *width,
-			    enum ui_align *alignment, char **colhdr);
+			    enum ui_align *alignment, const char **col_hdr);
 static void clear_header_list (struct ui_out *uiout);
 static void clear_table (struct ui_out *uiout);
 static void verify_field (struct ui_out *uiout, int *fldno, int *width,
@@ -247,17 +249,16 @@ ui_out_table_end (struct ui_out *uiout)
 
 void
 ui_out_table_header (struct ui_out *uiout, int width, enum ui_align alignment,
-		     const char *col_name,
-		     const char *colhdr)
+		     const std::string &col_name, const std::string &col_hdr)
 {
   if (!uiout->table.flag || uiout->table.body_flag)
     internal_error (__FILE__, __LINE__,
 		    _("table header must be specified after table_begin \
 and before table_body."));
 
-  append_header_to_list (uiout, width, alignment, col_name, colhdr);
+  append_header_to_list (uiout, width, alignment, col_name, col_hdr);
 
-  uo_table_header (uiout, width, alignment, col_name, colhdr);
+  uo_table_header (uiout, width, alignment, col_name, col_hdr);
 }
 
 static void
@@ -557,12 +558,11 @@ uo_table_end (struct ui_out *uiout)
 
 void
 uo_table_header (struct ui_out *uiout, int width, enum ui_align align,
-		 const char *col_name,
-		 const char *colhdr)
+		 const std::string &col_name, const std::string &col_hdr)
 {
   if (!uiout->impl->table_header)
     return;
-  uiout->impl->table_header (uiout, width, align, col_name, colhdr);
+  uiout->impl->table_header (uiout, width, align, col_name, col_hdr);
 }
 
 /* Clear the table associated with UIOUT.  */
@@ -694,12 +694,6 @@ uo_redirect (struct ui_out *uiout, struct ui_file *outstream)
 static void
 clear_header_list (struct ui_out *uiout)
 {
-  for (auto &it : uiout->table.headers)
-    {
-      xfree (it->colhdr);
-      xfree (it->col_name);
-    }
-
   uiout->table.headers.clear ();
   uiout->table.headers_iterator = uiout->table.headers.end ();
 }
@@ -708,26 +702,18 @@ static void
 append_header_to_list (struct ui_out *uiout,
 		       int width,
 		       enum ui_align alignment,
-		       const char *col_name,
-		       const char *colhdr)
+		       const std::string &col_name,
+		       const std::string &col_hdr)
 {
   std::unique_ptr<ui_out_hdr> temphdr (new ui_out_hdr ());
 
   temphdr->width = width;
   temphdr->alignment = alignment;
-  /* We have to copy the column title as the original may be an
-     automatic.  */
-  if (colhdr != NULL)
-    temphdr->colhdr = xstrdup (colhdr);
-  else
-    temphdr->colhdr = NULL;
 
-  if (col_name != NULL)
-    temphdr->col_name = xstrdup (col_name);
-  else if (colhdr != NULL)
-    temphdr->col_name = xstrdup (colhdr);
-  else
-    temphdr->col_name = NULL;
+  /* Make our own copy of the strings, since the lifetime of the original
+     versions may be too short.  */
+  temphdr->col_hdr = col_hdr;
+  temphdr->col_name = col_name;
 
   temphdr->colno = uiout->table.headers.size () + 1;
 
@@ -742,7 +728,7 @@ get_next_header (struct ui_out *uiout,
 		 int *colno,
 		 int *width,
 		 enum ui_align *alignment,
-		 char **colhdr)
+		 const char **col_hdr)
 {
   /* There may be no headers at all or we may have used all columns.  */
   if (uiout->table.headers_iterator == uiout->table.headers.end ())
@@ -753,7 +739,7 @@ get_next_header (struct ui_out *uiout,
   *colno = hdr->colno;
   *width = hdr->width;
   *alignment = hdr->alignment;
-  *colhdr = hdr->colhdr;
+  *col_hdr = hdr->col_hdr.c_str ();
 
   /* Advance the header pointer to the next entry.  */
   uiout->table.headers_iterator++;
@@ -771,7 +757,7 @@ verify_field (struct ui_out *uiout, int *fldno, int *width,
 	      enum ui_align *align)
 {
   struct ui_out_level *current = current_level (uiout);
-  char *text;
+  const char *text;
 
   if (uiout->table.flag)
     {
@@ -816,7 +802,7 @@ ui_out_data (struct ui_out *uiout)
 /* Access table field parameters.  */
 int
 ui_out_query_field (struct ui_out *uiout, int colno,
-		    int *width, int *alignment, char **col_name)
+		    int *width, int *alignment, const char **col_name)
 {
   if (!uiout->table.flag)
     return 0;
@@ -832,7 +818,7 @@ ui_out_query_field (struct ui_out *uiout, int colno,
 
       *width = hdr->width;
       *alignment = hdr->alignment;
-      *col_name = hdr->col_name;
+      *col_name = hdr->col_name.c_str ();
 
       return 1;
     }
diff --git a/gdb/ui-out.h b/gdb/ui-out.h
index e251d77..ed2911d 100644
--- a/gdb/ui-out.h
+++ b/gdb/ui-out.h
@@ -74,8 +74,9 @@ extern void ui_out_end (struct ui_out *uiout, enum ui_out_type type);
    field, ... }, ... ] }''.  If NR_ROWS is negative then there is at
    least one row.  */
 extern void ui_out_table_header (struct ui_out *uiout, int width,
-				 enum ui_align align, const char *col_name,
-				 const char *colhdr);
+				 enum ui_align align,
+				 const std::string &col_name,
+				 const std::string &col_hdr);
 
 extern void ui_out_table_body (struct ui_out *uiout);
 
@@ -129,7 +130,8 @@ extern void ui_out_flush (struct ui_out *uiout);
 extern int ui_out_test_flags (struct ui_out *uiout, int mask);
 
 extern int ui_out_query_field (struct ui_out *uiout, int colno,
-			       int *width, int *alignment, char **col_name);
+			       int *width, int *alignment,
+			       const char **col_name);
 
 /* HACK: Code in GDB is currently checking to see the type of ui_out
    builder when determining which output to produce.  This function is
@@ -152,8 +154,9 @@ typedef void (table_begin_ftype) (struct ui_out * uiout,
 typedef void (table_body_ftype) (struct ui_out * uiout);
 typedef void (table_end_ftype) (struct ui_out * uiout);
 typedef void (table_header_ftype) (struct ui_out * uiout, int width,
-				   enum ui_align align, const char *col_name,
-				   const char *colhdr);
+				   enum ui_align align,
+				   const std::string &col_name,
+				   const std::string &col_hdr);
 /* Note: level 0 is the top-level so LEVEL is always greater than
    zero.  */
 typedef void (ui_out_begin_ftype) (struct ui_out *uiout,