Add a Qt I/O Graph dialog.

For each graph you can set:
- Its visibility
- A name
- A display filter
- Color, from a fixed list
- Plot style: Line, Impulse, Bar, Stacked Bar, Dot, Square, Diamond
- Basic Y Axes (packets/s, bytes/s, bits/s)
- Computed Y Axes (SUM, MIN, AVG, MAX)
- Smoothing

You can pan and zoom using the mouse and keyboard. Clicking on a graph
selects the last packet for that interval. If all graphs have the same Y
axis a single label is shown, otherwise a legend is shown.

The time scale (X axis) can be toggled between relative seconds and the
time of day.

Graphs can be saved as PDF, PNG, BMP, and JPEG. Settings are "sticky"
via the io_graphs UAT.

To do:
- Minimize graph drawing delays.
- Figure out why smoothing differs from GTK+
- Everything else at the top of io_graph_dialog.cpp
- Fix empty resets.

A fair amount of code was copied from TCPStreamDialog. We might want to
subclass QCustomPlot and place the shared code there.

Move common syntax checking to SyntaxLineEdit.

Move some common code from ui/gtk/io_stat.c to ui/io_graph_item.[ch] and
use it in both GTK+ and Qt.

Make the io_graph_item_t array allocation in io_stat.c static. The
behavior should be identical and this gives us additional compile-time
checks.

Change-Id: I9a3d544469b7048f0761fdbf7bcf20f44ae76577
Reviewed-on: https://code.wireshark.org/review/435
Reviewed-by: Gerald Combs <gerald@wireshark.org>
Tested-by: Gerald Combs <gerald@wireshark.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/file.c b/file.c
index 95d2bd23dc..ef21b930b1 100644
--- a/file.c
+++ b/file.c
@@ -2382,6 +2382,11 @@ cf_retap_packets(capture_file *cf)
   guint                 tap_flags;
   psp_return_t          ret;
 
+  /* Presumably the user closed the capture file. */
+  if (cf == NULL) {
+    return CF_READ_ABORTED;
+  }
+  
   /* Do we have any tap listeners with filters? */
   filtering_tap_listeners = have_filtering_tap_listeners();