Migrate device utils WriteFile to AdbWrapper

build/android/pylib/device/device_utils.py

Index: build/android/pylib/device/device_utils.py
diff --git a/build/android/pylib/device/device_utils.py b/build/android/pylib/device/device_utils.py
index b75a41a2f1a2401e98982ad044386ec517984fff..b6b62aa3f8bd4d6a336ffe30525edbfdb3ea598f 100644
--- a/build/android/pylib/device/device_utils.py
+++ b/build/android/pylib/device/device_utils.py
@@ -24,6 +24,7 @@ from pylib.device import decorators
 from pylib.device import device_errors
 from pylib.device.commands import install_commands
 from pylib.utils import apk_helper
+from pylib.utils import device_temp_file
 from pylib.utils import host_utils
 from pylib.utils import parallelizer
 from pylib.utils import timeout_retry
@@ -429,13 +430,14 @@ class DeviceUtils(object):
 
     if not isinstance(cmd, basestring):
       cmd = ' '.join(cmd_helper.SingleQuote(s) for s in cmd)
-    if as_root and self.NeedsSU():
-      cmd = 'su -c %s' % cmd
     if env:
       env = ' '.join(env_quote(k, v) for k, v in env.iteritems())
       cmd = '%s %s' % (env, cmd)
     if cwd:
       cmd = 'cd %s && %s' % (cmd_helper.SingleQuote(cwd), cmd)
+    if as_root and self.NeedsSU():
+      # "su -c sh -c" allows using shell features in |cmd|

[Sami, 2014/11/12 19:45:38]

Random thought: subprocess lets you use shell=True/False to control this
behavior. It's mostly for security, which isn't the top priority here.

+      cmd = 'su -c sh -c %s' % cmd_helper.SingleQuote(cmd)

[perezju, 2014/11/12 19:30:41]

I also moved the root check to the end so that, e.g., having the options
cwd='/path/to/protected/folder' and as_root=True together work as expected.

     if timeout is None:
       timeout = self._default_timeout
 
@@ -866,16 +868,19 @@ class DeviceUtils(object):
       return self.old_interface.GetFileContents(device_path)
 
   @decorators.WithTimeoutAndRetriesFromInstance()
-  def WriteFile(self, device_path, contents, as_root=False, timeout=None,
-                retries=None):
+  def WriteFile(self, device_path, contents, as_root=False, force_push=False,
+                timeout=None, retries=None):
     """Writes |contents| to a file on the device.
 
     Args:
       device_path: A string containing the absolute path to the file to write
-                   on the device.
+          on the device.
       contents: A string containing the data to write to the device.
       as_root: A boolean indicating whether the write should be executed with
-               root privileges.
+          root privileges (if available).
+      force_push: A boolean indicating whether to force the operation to be
+          performed by pushing a file to the device. The default is, when the
+          contents are short, to pass the contents using a shell script instead.
       timeout: timeout in seconds
       retries: number of retries
 
@@ -884,39 +889,24 @@ class DeviceUtils(object):
       CommandTimeoutError on timeout.
       DeviceUnreachableError on missing device.
     """
-    if as_root:
-      if not self.old_interface.CanAccessProtectedFileContents():
-        raise device_errors.CommandFailedError(
-            'Cannot write to %s with root privileges.' % device_path)
-      self.old_interface.SetProtectedFileContents(device_path, contents)
+    if len(contents) < 512 and not force_push:
+      cmd = 'echo -n %s > %s' % (cmd_helper.SingleQuote(contents),
+                                 cmd_helper.SingleQuote(device_path))
+      self.RunShellCommand(cmd, as_root=as_root, check_return=True)

[perezju, 2014/11/12 19:30:41]

Now RunShellCommand will "do the right thing", so no need for special treatment
of the command here. This will also "automagically" fix the same bug for other
clients attempting to run echo (or other shell features) through RunShellCommand
with as_root=True.

Thanks Sami for helping to spot this!

     else:
-      self.old_interface.SetFileContents(device_path, contents)
-
-  @decorators.WithTimeoutAndRetriesFromInstance()
-  def WriteTextFile(self, device_path, text, as_root=False, timeout=None,
-                    retries=None):
-    """Writes |text| to a file on the device.
-
-    Assuming that |text| is a small string, this is typically more efficient
-    than |WriteFile|, as no files are pushed into the device.
-
-    Args:
-      device_path: A string containing the absolute path to the file to write
-                   on the device.
-      text: A short string of text to write to the file on the device.
-      as_root: A boolean indicating whether the write should be executed with
-               root privileges.
-      timeout: timeout in seconds
-      retries: number of retries
-
-    Raises:
-      CommandFailedError if the file could not be written on the device.
-      CommandTimeoutError on timeout.
-      DeviceUnreachableError on missing device.
-    """
-    cmd = 'echo %s > %s' % (cmd_helper.SingleQuote(text),
-                            cmd_helper.SingleQuote(device_path))
-    self.RunShellCommand(cmd, as_root=as_root, check_return=True)
+      with tempfile.NamedTemporaryFile() as host_temp:
+        host_temp.write(contents)
+        host_temp.flush()
+        if as_root and self.NeedsSU():
+          with device_temp_file.DeviceTempFile(self) as device_temp:
+            self.adb.Push(host_temp.name, device_temp.name)
+            # Here we need 'cp' rather than 'mv' because the temp and
+            # destination files might be on different file systems (e.g.
+            # on internal storage and an external sd card)
+            self.RunShellCommand(['cp', device_temp.name, device_path],
+                                 as_root=True, check_return=True)
+        else:
+          self.adb.Push(host_temp.name, device_path)
 
   @decorators.WithTimeoutAndRetriesFromInstance()
   def Ls(self, device_path, timeout=None, retries=None):