Allow RunShellCommand to work even with very large commands

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 272e613b6817f915a2cee039caf6ff53de13bea7..ae876dfe39f92002dc9dd5aa35677d5ce1e71cfd 100644
--- a/build/android/pylib/device/device_utils.py
+++ b/build/android/pylib/device/device_utils.py
@@ -427,6 +427,15 @@ class DeviceUtils(object):
       # using double quotes here to allow interpolation of shell variables
       return '%s=%s' % (key, cmd_helper.DoubleQuote(value))
 
+    def do_run(cmd):
+      try:
+        return self.adb.Shell(cmd)
+      except device_errors.AdbCommandFailedError as exc:
+        if check_return:
+          raise
+        else:
+          return exc.output
+
     if not isinstance(cmd, basestring):
       cmd = ' '.join(cmd_helper.SingleQuote(s) for s in cmd)
     if env:
@@ -440,13 +449,14 @@ class DeviceUtils(object):
     if timeout is None:
       timeout = self._default_timeout
 
-    try:
-      output = self.adb.Shell(cmd)
-    except device_errors.AdbCommandFailedError as e:
-      if check_return:
-        raise
-      else:
-        output = e.output
+    if len(cmd) < 512:

[jbudorick, 2014/11/25 17:05:26]

We should de-magic 512. "MAX_ADB_COMMAND_LENGTH" or something like that.

+      output = do_run(cmd)
+    else:
+      with device_temp_file.DeviceTempFile(self, suffix='.sh') as script:
+        # |as_root| must be False, and |force_push| must be True,
+        # otherwise WriteFile may introduce infinite recursion

[jbudorick, 2014/11/25 17:05:26]

This worries me. It's the same kind of cyclical dependency we had in the
previous version of device_temp_file -- one that is correctly avoided _now_ and
well-commented, but is tricky to modify and liable to be sneakily broken by
changes elsewhere (in this case, in WriteFile). Maybe would should instead be
doing this with tempfile + device_temp_file + adb.Push?

+        self.WriteFile(script.name, cmd, as_root=False, force_push=True)

[perezju, 2014/11/25 16:25:33]

look, our first non-artificial use of force_push! :)

+        output = do_run('sh %s' % script.name_quoted)
 
     output = output.splitlines()
     if single_line: