bitbake: fetch2: implement progress support

Implement progress reporting support specifically for the fetchers. For
fetch tasks we don't necessarily know which fetcher will be used (we
might initially be fetching a git:// URI, but if we instead download a
mirror tarball we may fetch that over http using wget). These programs
also have different abilities as far as reporting progress goes (e.g.
wget gives us percentage complete and rate, git gives this some of the
time depending on what stage it's at). Additionally we filter out the
progress output before it makes it to the logs, in order to prevent the
logs filling up with junk.

At the moment this is only implemented for the wget and git fetchers
since they are the most commonly used (and svn doesn't seem to support
any kind of progress output, at least not without doing a relatively
expensive remote file listing first).

Line changes such as the ones you get in git's output as it progresses
don't make it to the log files, you only get the final state of the line
so the logs aren't filled with progress information that's useless after
the fact.

Part of the implementation for [YOCTO #5383].

(Bitbake rev: 4027649f422ee64b1c4e1ad8d48ac295050afbff)

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

bitbake/lib/bb/progress.py

@@ -58,6 +58,37 @@ class ProgressHandler(object):
             self._lastevent = ts
             self._progress = progress
 
+class LineFilterProgressHandler(ProgressHandler):
+    """
+    A ProgressHandler variant that provides the ability to filter out
+    the lines if they contain progress information. Additionally, it
+    filters out anything before the last line feed on a line. This can
+    be used to keep the logs clean of output that we've only enabled for
+    getting progress, assuming that that can be done on a per-line
+    basis.
+    """
+    def __init__(self, d, outfile=None):
+        self._linebuffer = ''
+        super(LineFilterProgressHandler, self).__init__(d, outfile)
+
+    def write(self, string):
+        self._linebuffer += string
+        while True:
+            breakpos = self._linebuffer.find('\n') + 1
+            if breakpos == 0:
+                break
+            line = self._linebuffer[:breakpos]
+            self._linebuffer = self._linebuffer[breakpos:]
+            # Drop any line feeds and anything that precedes them
+            lbreakpos = line.rfind('\r') + 1
+            if lbreakpos:
+                line = line[lbreakpos:]
+            if self.writeline(line):
+                super(LineFilterProgressHandler, self).write(line)
+
+    def writeline(self, line):
+        return True
+
 class BasicProgressHandler(ProgressHandler):
     def __init__(self, d, regex=r'(\d+)%', outfile=None):
         super(BasicProgressHandler, self).__init__(d, outfile)