[PATCH] Be lazy about refreshing the windows in tui_show_frame_info (PR tui/13378)

Patrick Palka
2015-06-30T02:32:31Z

This revised patch makes sure that tui_set_locator_info returns 1 when the
locator is first constructed, just in case none of the later checks trigger
for some reason.

gdb/ChangeLog:

* tui/tui-stack.c (tui_set_locator_info): Change prototype to
return an int instead of void. Return whether the locator
window has changed.
(tui_show_frame_info): If the locator info has not changed, then
bail out early to avoid refreshing the windows.
---
gdb/tui/tui-stack.c | 67 ++++++++++++++++++++++++++++++++++++++++-------------
1 file changed, 51 insertions(+), 16 deletions(-)

diff --git a/gdb/tui/tui-stack.c b/gdb/tui/tui-stack.c
index b17d303..e077245 100644
--- a/gdb/tui/tui-stack.c
+++ b/gdb/tui/tui-stack.c
@@ -48,10 +48,10 @@ static char *tui_get_function_from_frame (struct frame_info *fi);
static void tui_set_locator_fullname (const char *fullname);

/* Update the locator, with the provided arguments. */
-static void tui_set_locator_info (struct gdbarch *gdbarch,
- const char *fullname,
- const char *procname,
- int lineno, CORE_ADDR addr);
+static int tui_set_locator_info (struct gdbarch *gdbarch,
+ const char *fullname,
+ const char *procname,
+ int lineno, CORE_ADDR addr);

static void tui_update_command (char *, int);
\f
@@ -292,8 +292,12 @@ tui_set_locator_fullname (const char *fullname)
strcat_to_buf (element->full_name, MAX_LOCATOR_ELEMENT_LEN, fullname);
}

-/* Update the locator, with the provided arguments. */
-static void
+/* Update the locator, with the provided arguments.
+
+ Returns 1 if any of the locator's fields were actually changed,
+ and 0 otherwise. */
+
+static int
tui_set_locator_info (struct gdbarch *gdbarch,
const char *fullname,
const char *procname,
@@ -302,21 +306,36 @@ tui_set_locator_info (struct gdbarch *gdbarch,
{
struct tui_gen_win_info *locator = tui_locator_win_info_ptr ();
struct tui_locator_element *element;
+ int locator_changed_p = 0;

/* Allocate the locator content if necessary. */
if (locator->content_size <= 0)
{
locator->content = tui_alloc_content (1, LOCATOR_WIN);
locator->content_size = 1;
+ locator_changed_p = 1;
}

element = &locator->content[0]->which_element.locator;
+
+ if (procname != NULL)
+ locator_changed_p |= strncmp (element->proc_name, procname,
+ MAX_LOCATOR_ELEMENT_LEN) != 0;
+ locator_changed_p |= lineno != element->line_no;
+ locator_changed_p |= addr != element->addr;
+ locator_changed_p |= gdbarch != element->gdbarch;
+ if (fullname != NULL)
+ locator_changed_p |= strncmp (element->full_name, fullname,
+ MAX_LOCATOR_ELEMENT_LEN) != 0;
+
element->proc_name[0] = (char) 0;
strcat_to_buf (element->proc_name, MAX_LOCATOR_ELEMENT_LEN, procname);
element->line_no = lineno;
element->addr = addr;
element->gdbarch = gdbarch;
tui_set_locator_fullname (fullname);
+
+ return locator_changed_p;
}

/* Update only the full_name portion of the locator. */
@@ -327,11 +346,14 @@ tui_update_locator_fullname (const char *fullname)
tui_show_locator_content ();
}

-/* Function to print the frame information for the TUI. */
+/* Function to print the frame information for the TUI. The windows are
+ refreshed only if frame information has changed since the last refresh. */
+
void
tui_show_frame_info (struct frame_info *fi)
{
struct tui_win_info *win_info;
+ int locator_changed_p;
int i;

if (fi)
@@ -349,15 +371,23 @@ tui_show_frame_info (struct frame_info *fi)
&& tui_source_is_displayed (symtab_to_fullname (sal.symtab));

if (get_frame_pc_if_available (fi, &pc))
- tui_set_locator_info (get_frame_arch (fi),
- (sal.symtab == 0
- ? "??" : symtab_to_fullname (sal.symtab)),
- tui_get_function_from_frame (fi),
- sal.line,
- pc);
+ locator_changed_p
+ = tui_set_locator_info (get_frame_arch (fi),
+ (sal.symtab == 0
+ ? "??" : symtab_to_fullname (sal.symtab)),
+ tui_get_function_from_frame (fi),
+ sal.line,
+ pc);
else
- tui_set_locator_info (get_frame_arch (fi),
- "??", _("<unavailable>"), sal.line, 0);
+ locator_changed_p
+ = tui_set_locator_info (get_frame_arch (fi),
+ "??", _("<unavailable>"), sal.line, 0);
+
+ /* If the locator information has not changed, then frame information has
+ not changed. If frame information has not changed, then the windows'
+ contents will not change. So don't bother refreshing the windows. */
+ if (!locator_changed_p)
+ return;

tui_show_locator_content ();
start_line = 0;
@@ -431,7 +461,12 @@ tui_show_frame_info (struct frame_info *fi)
}
else
{
- tui_set_locator_info (NULL, NULL, NULL, 0, (CORE_ADDR) 0);
+ locator_changed_p
+ = tui_set_locator_info (NULL, NULL, NULL, 0, (CORE_ADDR) 0);
+
+ if (!locator_changed_p)
+ return;
+
tui_show_locator_content ();
for (i = 0; i < (tui_source_windows ())->count; i++)
{
--
2.5.0.rc0.5.g91e10c5.dirty