DeviceUtils.StartInstrumentation: Shrink command-line

build/android/devil/android/device_utils.py

Index: build/android/devil/android/device_utils.py
diff --git a/build/android/devil/android/device_utils.py b/build/android/devil/android/device_utils.py
index e9d16935ad2fc307b406fb5e8e45b5b7decf4993..719add03f0810f3df0efc511501a3af1b6e352c8 100644
--- a/build/android/devil/android/device_utils.py
+++ b/build/android/devil/android/device_utils.py
@@ -936,7 +936,14 @@ class DeviceUtils(object):
     for k, v in extras.iteritems():
       cmd.extend(['-e', str(k), str(v)])
     cmd.append(component)
-    return self.RunShellCommand(cmd, check_return=True, large_output=True)
+
+    # Store the package name in a shell variable to help the command stay under
+    # the _MAX_ADB_COMMAND_LENGTH limit.
+    package = component.split('/')[0]
+    shell_snippet = 'p=%s;%s' % (package,
+                                 cmd_helper.ShrinkToSnippet(cmd, 'p', package))

[jbudorick, 2015/10/08 20:55:39]

Hrm, I was thinking something more along the lines of

  shell_snippet = cmd_helper.ShrinkToSnippet(cmd, [package])

where the second parameter is a list of strings to shrink and then have
ShrinkToSnippet handle the shell variable part. (or just do ShrinkToSnippet(cmd)
and have it figure out what to shrink, but giving it hints seems a bit more
straightforward)

[agrieve, 2015/10/09 00:08:29]

The helper is quite limiting already since it can only act on a single cmd list.
If it inserts the variable as well, then you couldn't efficiently combine two
commands at once that use the same substitutions. 
e.g.:
cmd1 =['foo', 'somelongarg1', 'somelongarg2']
cmd2 =['foo', 'somelongarg3', 'somelongarg4']

snippet1 = ShrinkToSnippet(cmd1, 'a', 'somelongarg')
snippet2 = ShrinkToSnippet(cmd2, 'a', 'somelongarg')
cmd = 'a=somelongarg;%s;%s' % (snippet1, snippet2)

I think it'd be best to just leave it as is and wait to see if it can be used
elsewhere before finalizing its API. E.g. it can't be used in
https://codereview.chromium.org/1398613002/, although I don't see how we could
come up with a helper that would.

[jbudorick, 2015/10/14 17:59:09]

Fair enough; I'm ok with landing this as-is and iterating on the interface.

+    return self.RunShellCommand(shell_snippet, check_return=True,
+                                large_output=True)
 
   @decorators.WithTimeoutAndRetriesFromInstance()
   def BroadcastIntent(self, intent_obj, timeout=None, retries=None):