Tracing: Add Chrome Trace Format Visualizer plugin

This new plugin adds a viewer for Chrome Trace Format (CTF) files
(aka Trace Event Format). It uses the same UI components as the
QML Profiler timeline and the Perf Profiler.

The Trace Event Format is generated by different kinds of tracing tools.
Usually the files are display with the trace-viewer, built into Chrome
(chrome://tracing). This plugin was developed because of the high memory
usage of trace-viewer, which makes it difficult to use with trace files
bigger than 100 MB.

The plugin fully supports all event types used in data generated by
LTTng, converted to CTF by https://github.com/KDAB/ctf2ctf.
Some of the more advanced event types used for example in Android system
traces, though, are not supported. The viewer will silently ignore
unsupported event types.

Supported Event Types:
- Begin, End, Duration and Instant events
- Counter events (graphs)
- Metadata events (process and thread name)

The plugin uses nlohmann/json instead of QJson because of the ~128 MB
object size limit by QJson.

[ChangeLog][Tracing][CtfVisualizer] Added Chrome Trace Format Visualizer plugin

Change-Id: I5969f7f83f3305712d4aec04487e2403510af64b
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

1 files changed, 39 insertions, 0 deletions

diff --git a/README.md b/README.md
index 2293ae8015..db4b8a97ea 100644
--- a/README.md
+++ b/README.md
@@ -465,3 +465,42 @@ SQLite (https://www.sqlite.org) is in the Public Domain.
   This Font Software is licensed under the SIL Open Font License, Version 1.1.
 
   The font and license files can be found in QtCreator/src/libs/3rdparty/fonts.
+
+### JSON Library by Niels Lohmann
+
+  Used by the Chrome Trace Format Visualizer plugin instead of QJson
+  because of QJson's current hard limit of 128 Mb object size and
+  trace files often being much larger.
+
+  The sources can be found in `QtCreator/src/libs/3rdparty/json`.
+
+  The class is licensed under the MIT License:
+
+  Copyright © 2013-2019 Niels Lohmann
+
+  Permission is hereby granted, free of charge, to any person obtaining a
+  copy of this software and associated documentation files (the “Software”), to
+  deal in the Software without restriction, including without limitation the
+  rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is furnished
+  to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included
+  in all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS
+  OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+  \endcode
+
+  The class contains the UTF-8 Decoder from Bjoern Hoehrmann which is
+  licensed under the MIT License (see above). Copyright © 2008-2009 Björn
+  Hoehrmann bjoern@hoehrmann.de
+
+  The class contains a slightly modified version of the Grisu2 algorithm
+  from Florian Loitsch which is licensed under the MIT License (see above).
+  Copyright © 2009 Florian Loitsch