Add gtest target support for runtest --path.

This is a rough initial version. It makes several assumptions:
 - assumes each test source file is built into module with name equal
to basename of source file
 - assumes tests get installed into /data/nativetest

However, given those assumptions, both:
$ runtest --path <path to directory containing gtest source> and
$ runtest --path <path to single source file>
should work.

Coming soon: gtest host support

Bugs 4563370, 4584339

Change-Id: Ia42aeed7f9ee6402b0ceb7b5ccaaa66ac636fe49

testrunner/android_mk.py

@@ -21,25 +21,26 @@ Specifications for Android.mk can be found at
 development/ndk/docs/ANDROID-MK.txt
 """
 
+import os
 import re
 from sets import Set
 
+import logger
 
 class AndroidMK(object):
   """In memory representation of Android.mk file."""
 
   _RE_INCLUDE = re.compile(r'include\s+\$\((.+)\)')
+  _RE_VARIABLE_REF = re.compile(r'\$\((.+)\)')
   _VAR_DELIMITER = ":="
   FILENAME = "Android.mk"
   CERTIFICATE = "LOCAL_CERTIFICATE"
   PACKAGE_NAME = "LOCAL_PACKAGE_NAME"
 
-  def __init__(self, app_path=None):
+  def __init__(self):
     self._includes = Set() # variables included in makefile
     self._variables = {} # variables defined in makefile
-
-    if app_path:
-      self.ParseMK(app_path)
+    self._has_gtestlib = False
 
   def _ProcessMKLine(self, line):
     """Add a variable definition or include.
@@ -56,6 +57,9 @@ class AndroidMK(object):
       parts = line.split(self._VAR_DELIMITER)
       if len(parts) > 1:
         self._variables[parts[0].strip()] = parts[1].strip()
+    # hack, look for explicit mention of libgtest_main
+    if line.find('libgtest_main') != -1:
+      self._has_gtestlib = True
 
   def GetVariable(self, identifier):
     """Retrieve makefile variable.
@@ -69,6 +73,38 @@ class AndroidMK(object):
     # so None is returned if identifier not found
     return self._variables.get(identifier, None)
 
+  def GetExpandedVariable(self, identifier):
+    """Retrieve makefile variable.
+
+    If variable value refers to another variable, recursively expand it to
+    find its literal value
+
+    Args:
+      identifier: name of variable to retrieve
+    Returns:
+      value of specified identifier, None if identifier not found in makefile
+    """
+    # use dict.get(x) rather than dict[x] to avoid KeyError exception,
+    # so None is returned if identifier not found
+    return self.__RecursiveGetVariable(identifier, Set())
+
+  def __RecursiveGetVariable(self, identifier, visited_variables):
+    variable_value = self.GetVariable(identifier)
+    if not variable_value:
+      return None
+    if variable_value in visited_variables:
+      raise RuntimeError('recursive loop found for makefile variable %s'
+                         % variable_value)
+    m = self._RE_VARIABLE_REF.match(variable_value)
+    if m:
+      logger.SilentLog('Found variable ref %s for identifier %s'
+                       % (variable_value, identifier))
+      variable_ref = m.group(1)
+      visited_variables.add(variable_ref)
+      return self.__RecursiveGetVariable(variable_ref, visited_variables)
+    else:
+      return variable_value
+
   def HasInclude(self, identifier):
     """Check variable is included in makefile.
 
@@ -79,18 +115,57 @@ class AndroidMK(object):
     """
     return identifier in self._includes
 
-  def ParseMK(self, app_path):
+  def HasJavaLibrary(self, library_name):
+    """Check if library is specified as a local java library in makefile.
+
+    Args:
+      library_name: name of library to check
+    Returns:
+      True if library_name is included in makefile, otherwise False
+    """
+    java_lib_string = self.GetExpandedVariable('LOCAL_JAVA_LIBRARIES')
+    if java_lib_string:
+      java_libs = java_lib_string.split(' ')
+      return library_name in java_libs
+    return False
+
+  def HasGTest(self):
+    """Check if makefile includes rule to build a native gtest.
+
+    Returns:
+      True if rule to build native test is in makefile, otherwise False
+    """
+    return self._has_gtestlib or self.HasInclude('BUILD_NATIVE_TEST')
+
+  def _ParseMK(self, mk_path):
     """Parse Android.mk at the specified path.
 
     Args:
-      app_path: path to folder containing Android.mk
+      mk_path: path to Android.mk
     Raises:
       IOError: Android.mk cannot be found at given path, or cannot be opened
           for reading
     """
-    self.app_path = app_path.rstrip("/")
-    self.mk_path = "%s/%s" % (self.app_path, self.FILENAME)
-    mk = open(self.mk_path)
+    mk = open(mk_path)
     for line in mk:
       self._ProcessMKLine(line)
     mk.close()
+
+
+def CreateAndroidMK(path, filename=AndroidMK.FILENAME):
+  """Factory method for creating a AndroidMK.
+
+  Args:
+    path: the directory of the make file
+    filename: the filename of the makefile
+
+  Return:
+    the AndroidMK or None if there was no file present
+  """
+  mk_path = os.path.join(path, filename)
+  if os.path.isfile(mk_path):
+    mk = AndroidMK()
+    mk._ParseMK(mk_path)
+    return mk
+  else:
+    return None