[Android] Tune DeviceUtils commands that are prone to large outputs.

build/android/pylib/device/device_utils.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Provides a variety of device interactions based on adb.
 
 Eventually, this will be based on adb_wrapper.
 """
 # pylint: disable=unused-argument
 
@@ skipping 557 matching lines @@
       if not output:
         return ''
       elif len(output) == 1:
         return output[0]
       else:
         msg = 'one line of output was expected, but got: %s'
         raise device_errors.CommandFailedError(msg % output, str(self))
     else:
       return output
 
+  def _RunPipedShellCommand(self, script, **kwargs):
+    PIPESTATUS_LEADER = 'PIPESTATUS: '
+
+    script += '; echo "%s${PIPESTATUS[@]}"' % PIPESTATUS_LEADER
+    kwargs['check_return'] = True
+    output = self.RunShellCommand(script, **kwargs)
+    pipestatus_line = output[-1]
+
+    if not pipestatus_line.startswith(PIPESTATUS_LEADER):
+      logging.error('Pipe exit statuses of shell script missing.')
+      raise device_errors.AdbShellCommandFailedError(
+          script, output, status=None,
+          device_serial=self.adb.GetDeviceSerial())
+
+    output = output[:-1]
+    statuses = [
+        int(s) for s in pipestatus_line[len(PIPESTATUS_LEADER):].split()]
+    if any(statuses):
+      raise device_errors.AdbShellCommandFailedError(
+          script, output, status=statuses,
+          device_serial=self.adb.GetDeviceSerial())
+    return output
+
   @decorators.WithTimeoutAndRetriesFromInstance()
   def KillAll(self, process_name, signum=device_signal.SIGKILL, as_root=False,
               blocking=False, quiet=False, timeout=None, retries=None):
     """Kill all processes with the given name on the device.
 
     Args:
       process_name: A string containing the name of the process to kill.
       signum: An integer containing the signal number to send to kill. Defaults
               to SIGKILL (9).
       as_root: A boolean indicating whether the kill should be executed with
@@ skipping 435 matching lines @@
     ls_out = self.RunShellCommand(['ls', '-l', device_path], as_root=as_root,
                                   check_return=True)
     for line in ls_out:
       m = self._LS_RE.match(line)
       if m and m.group('name') == posixpath.basename(device_path):
         size = int(m.group('size'))
         break
     else:
       logging.warning('Could not determine size of %s.', device_path)
 
-    if size is None or size <= self._MAX_ADB_OUTPUT_LENGTH:
+    if 0 < size <= self._MAX_ADB_OUTPUT_LENGTH:
       return _JoinLines(self.RunShellCommand(
           ['cat', device_path], as_root=as_root, check_return=True))
     elif as_root and self.NeedsSU():
       with device_temp_file.DeviceTempFile(self.adb) as device_temp:
         self.RunShellCommand(['cp', device_path, device_temp.name],
                              as_root=True, check_return=True)
         return self._ReadFileWithPull(device_temp.name)
     else:
       return self._ReadFileWithPull(device_path)
 
@@ skipping 315 matching lines @@
 
     Returns:
       A dict mapping process name to PID for each process that contained the
       provided |process_name|.
 
     Raises:
       CommandTimeoutError on timeout.
       DeviceUnreachableError on missing device.
     """
     procs_pids = {}
-    for line in self.RunShellCommand('ps', check_return=True):
+    try:
+      ps_output = self._RunPipedShellCommand(
+          'ps | grep -F %s' % cmd_helper.SingleQuote(process_name))
+    except device_errors.AdbShellCommandFailedError as e:
+      if e.status and isinstance(e.status, list) and not e.status[0]:
+        # If ps succeeded but grep failed, there were no processes with the
+        # given name.
+        return procs_pids
+      else:
+        raise
+
+    for line in ps_output:
       try:
         ps_data = line.split()
         if process_name in ps_data[-1]:
           procs_pids[ps_data[-1]] = ps_data[1]
       except IndexError:
         pass
     return procs_pids
 
   @decorators.WithTimeoutAndRetriesFromInstance()
   def TakeScreenshot(self, host_path=None, timeout=None, retries=None):
@@ skipping 51 matching lines @@
     except device_errors.CommandFailedError:
       logging.exception('Error getting memory usage from status')
 
     return result
 
   def _GetMemoryUsageForPidFromSmaps(self, pid):
     SMAPS_COLUMNS = (
         'Size', 'Rss', 'Pss', 'Shared_Clean', 'Shared_Dirty', 'Private_Clean',
         'Private_Dirty')
 
-    showmap_out = self.RunShellCommand(
-        ['showmap', str(pid)], as_root=True, check_return=True)
-    if not showmap_out:
-      raise device_errors.CommandFailedError('No output from showmap')
+    showmap_out = self._RunPipedShellCommand(
+        'showmap %d | grep TOTAL' % int(pid), as_root=True)
 
     split_totals = showmap_out[-1].split()
     if (not split_totals
         or len(split_totals) != 9
         or split_totals[-1] != 'TOTAL'):
       raise device_errors.CommandFailedError(
           'Invalid output from showmap: %s' % '\n'.join(showmap_out))
 
     return dict(itertools.izip(SMAPS_COLUMNS, (int(n) for n in split_totals)))
 
@@ skipping 88 matching lines @@
     """Returns client cache."""
     if client_name not in self._client_caches:
       self._client_caches[client_name] = {}
     return self._client_caches[client_name]
 
   def _ClearCache(self):
     """Clears all caches."""
     for client in self._client_caches:
       self._client_caches[client].clear()
     self._cache.clear()