lib: implement basic task progress support

For long-running tasks where we have some output from the task that
gives us some idea of the progress of the task (such as a percentage
complete), provide the means to scrape the output for that progress
information and show it to the user in the default knotty terminal
output in the form of a progress bar. This is implemented using a new
TaskProgress event as well as some code we can insert to do output
scanning/filtering.

Any task can fire TaskProgress events; however, if you have a shell task
whose output you wish to scan for progress information, you just need to
set the "progress" varflag on the task. This can be set to:
 * "percent" to just look for a number followed by a % sign
 * "percent:<regex>" to specify your own regex matching a percentage
   value (must have a single group which matches the percentage number)
 * "outof:<regex>" to look for the specified regex matching x out of y
   items completed (must have two groups - first group needs to be x,
   second y).
We can potentially extend this in future but this should be a good
start.

Part of the implementation for [YOCTO #5383].

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 48 insertions, 4 deletions

diff --git a/lib/progressbar/progressbar.py b/lib/progressbar/progressbar.py
index 0b9dcf763..2873ad6ca 100644
--- a/lib/progressbar/progressbar.py
+++ b/lib/progressbar/progressbar.py
@@ -3,6 +3,8 @@
 # progressbar  - Text progress bar library for Python.
 # Copyright (c) 2005 Nilton Volpato
 #
+# (With some small changes after importing into BitBake)
+#
 # This library is free software; you can redistribute it and/or
 # modify it under the terms of the GNU Lesser General Public
 # License as published by the Free Software Foundation; either
@@ -261,12 +263,14 @@ class ProgressBar(object):
         now = time.time()
         self.seconds_elapsed = now - self.start_time
         self.next_update = self.currval + self.update_interval
-        self.fd.write(self._format_line() + '\r')
+        output = self._format_line()
+        self.fd.write(output + '\r')
         self.fd.flush()
         self.last_update_time = now
+        return output
 
 
-    def start(self):
+    def start(self, update=True):
         """Starts measuring time, and prints the bar at 0%.
 
         It returns self so you can use it like this:
@@ -289,8 +293,12 @@ class ProgressBar(object):
             self.update_interval = self.maxval / self.num_intervals
 
 
-        self.start_time = self.last_update_time = time.time()
-        self.update(0)
+        self.start_time = time.time()
+        if update:
+            self.last_update_time = self.start_time
+            self.update(0)
+        else:
+            self.last_update_time = 0
 
         return self
 
diff --git a/lib/progressbar/widgets.py b/lib/progressbar/widgets.py
index 6434ad559..77285ca7a 100644
--- a/lib/progressbar/widgets.py
+++ b/lib/progressbar/widgets.py
@@ -353,3 +353,39 @@ class BouncingBar(Bar):
         if not self.fill_left: rpad, lpad = lpad, rpad
 
         return '%s%s%s%s%s' % (left, lpad, marker, rpad, right)
+
+
+class BouncingSlider(Bar):
+    """
+    A slider that bounces back and forth in response to update() calls
+    without reference to the actual value. Based on a combination of
+    BouncingBar from a newer version of this module and RotatingMarker.
+    """
+    def __init__(self, marker='<=>'):
+        self.curmark = -1
+        self.forward = True
+        Bar.__init__(self, marker=marker)
+    def update(self, pbar, width):
+        left, marker, right = (format_updatable(i, pbar) for i in
+                               (self.left, self.marker, self.right))
+
+        width -= len(left) + len(right)
+        if width < 0:
+            return ''
+
+        if pbar.finished: return '%s%s%s' % (left, width * '=', right)
+
+        self.curmark = self.curmark + 1
+        position = int(self.curmark % (width * 2 - 1))
+        if position + len(marker) > width:
+            self.forward = not self.forward
+            self.curmark = 1
+            position = 1
+        lpad = ' ' * (position - 1)
+        rpad = ' ' * (width - len(marker) - len(lpad))
+
+        if not self.forward:
+            temp = lpad
+            lpad = rpad
+            rpad = temp
+        return '%s%s%s%s%s' % (left, lpad, marker, rpad, right)