dbus-top: initial commits

This commit covers the basic functionalities of the dbus-top tool.

The UI is divided into 3 windows as follows:

  +--------------------------+  Window list
  |         Window A         |  A: Summary statistics
  +------------+-------------+  B: Sensor list or detail
  |  Window B  |   Window C  |  C: Detailed statistics
  +------------+-------------+

To navigate the UI:
* Use tab to navigate each window

When a window is highlighted:
  In Window B:
  * Press esc key 3 times to leave the current sensor selection

  In Window C:
  * Press [Enter] to show/hide pop-up menu for column selectio
  * Press [Left]  to move highlight cursor to the left
  * Press [Right] to move highlight cursor to the right
  * Press [A] to sort by the highlighted column in ascending order
  * Press [D] to sort by the highlighted column in descending order

To add recipe to Yocto and build the recipe:
1) Copy and paste the content of the .bb file into a folder that can be
   detected by bitbake, such as meta-phosphor/recipes-phosphor/ipmi.
2) run "devtool modify -n dbus-top (path_to_openbmc_tools)/dbus-top/".

Signed-off-by: Adedeji Adebisi <adedejiadebisi01@gmail.com>
Change-Id: Id58ba30b815cfd9d18f54cf477d749dbdbc4545b
diff --git a/dbus-top/meson.build b/dbus-top/meson.build
new file mode 100644
index 0000000..60d4641
--- /dev/null
+++ b/dbus-top/meson.build
@@ -0,0 +1,48 @@
+# Copyright 2021 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+project('dbus-top', 'cpp',
+    version: '0.1',
+    default_options: 
+    [
+        'cpp_std=c++17',
+    ],
+)
+
+cmake = import('cmake')
+fmt_proj = cmake.subproject('fmt')
+fmt_dep = fmt_proj.dependency('fmt')
+
+bindir = get_option('prefix') / get_option('bindir')
+executable('dbus-top',
+    [
+        'menu.cpp',
+        'analyzer.cpp',
+        'dbus_capture.cpp',
+        'sensorhelper.cpp',
+        'xmlparse.cpp',
+        'views.cpp',
+        'main.cpp',
+    ],
+    dependencies:
+    [
+        dependency('systemd'),
+        dependency('sdbusplus'),
+        dependency('ncurses'),
+        dependency('threads'),
+        fmt_dep
+    ],
+    install: true,
+    install_dir: bindir
+)