Add instance-level in-memory cache for PushIfNeeded().

build/android/pylib/android_commands.py

 # Copyright (c) 2012 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 an interface to communicate with the device via the adb command.
 
 Assumes adb binary is currently on system path.
 """
 
 import collections
@@ skipping 242 matching lines @@
     self.logcat_process = None
     self._logcat_tmpoutfile = None
     self._pushed_files = []
     self._device_utc_offset = None
     self._potential_push_size = 0
     self._actual_push_size = 0
     self._external_storage = ''
     self._util_wrapper = ''
     self._api_strict_mode = api_strict_mode
     self._system_properties = system_properties.SystemProperties(self.Adb())
+    self._push_if_needed_cache = {}
 
     if not self._api_strict_mode:
       logging.warning(
           'API STRICT MODE IS DISABLED.\n'
           'It should be enabled as soon as possible as it will eventually '
           'become the default.')
 
   @property
   def system_properties(self):
     return self._system_properties
@@ skipping 685 matching lines @@
     """Pushes |host_path| to |device_path|.
 
     Works for files and directories. This method skips copying any paths in
     |test_data_paths| that already exist on the device with the same hash.
 
     All pushed files can be removed by calling RemovePushedFiles().
     """
     MAX_INDIVIDUAL_PUSHES = 50
     assert os.path.exists(host_path), 'Local path not found %s' % host_path
 
+    # See if the file on the host changed since the last push (if any) and
+    # return early if it didn't. Note that this shortcut assumes that the tests
+    # on the device don't modify the files.
+    if not os.path.isdir(host_path):
+      if host_path in self._push_if_needed_cache:
+        host_path_mtime = self._push_if_needed_cache[host_path]
+        if host_path_mtime == os.stat(host_path).st_mtime:
+          return
+
     def GetHostSize(path):
       return int(cmd_helper.GetCmdOutput(['du', '-sb', path]).split()[0])
 
     size = GetHostSize(host_path)
     self._pushed_files.append(device_path)
     self._potential_push_size += size
 
     changed_files = self.GetFilesChanged(host_path, device_path)
     logging.info('Found %d files that need to be pushed to %s',
         len(changed_files), device_path)
     if not changed_files:
       return
 
     def Push(host, device):
       # NOTE: We can't use adb_interface.Push() because it hardcodes a timeout
       # of 60 seconds which isn't sufficient for a lot of users of this method.
       push_command = 'push %s %s' % (host, device)
       self._LogShell(push_command)
 
       # Retry push with increasing backoff if the device is busy.
       retry = 0
       while True:
         output = self._adb.SendCommand(push_command, timeout_time=30 * 60)
         if _HasAdbPushSucceeded(output):
+          if not os.path.isdir(host_path):
+            self._push_if_needed_cache[host] = os.stat(host).st_mtime
           return
         if retry < 3:
           retry += 1
           wait_time = 5 * retry
           logging.error('Push failed, retrying in %d seconds: %s' %
                         (wait_time, output))
           time.sleep(wait_time)
         else:
           raise Exception('Push failed: %s' % output)
 
@@ skipping 755 matching lines @@
   """
   def __init__(self, output):
     self._output = output
 
   def write(self, data):
     data = data.replace('\r\r\n', '\n')
     self._output.write(data)
 
   def flush(self):
     self._output.flush()