Scripts to generate Android.mk for framework Skia.

In order to create Android.mk, run

>> python platform_tools/android/bin/gyp_to_android.py

For the change in the Android.mk file, see
https://googleplex-android-review.git.corp.google.com/#/c/408170/

(SkipBuildbotRuns)

BUG=skia:1975
R=djsollen@google.com, epoger@google.com

Author: scroggo@google.com

Review URL: https://codereview.chromium.org/140503007

git-svn-id: http://skia.googlecode.com/svn/trunk@13344 2bbb7eff-a529-9590-31e7-b0007b416f81

11 files changed, 984 insertions, 0 deletions

diff --git a/platform_tools/android/bin/android_framework_gyp.py b/platform_tools/android/bin/android_framework_gyp.py
new file mode 100644
index 0000000000..7654492f07
--- /dev/null
+++ b/platform_tools/android/bin/android_framework_gyp.py
@@ -0,0 +1,79 @@
+#!/usr/bin/python
+
+# Copyright 2014 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+Modified version of gyp_skia, used by gyp_to_android.py to generate Android.mk
+"""
+
+import os
+import sys
+
+SCRIPT_DIR = os.path.abspath(os.path.dirname(__file__))
+
+# Unlike gyp_skia, this file is nested deep inside Skia. Find Skia's trunk dir.
+# This line depends on the fact that the script is three levels deep
+# (specifically, it is in platform_tools/android/bin).
+SKIA_DIR = os.path.normpath(os.path.join(SCRIPT_DIR, os.pardir, os.pardir,
+                                         os.pardir))
+dir_contents = os.listdir(SKIA_DIR)
+assert 'third_party' in dir_contents and 'gyp' in dir_contents
+
+# Directory within which we can find the gyp source.
+GYP_SOURCE_DIR = os.path.join(SKIA_DIR, 'third_party', 'externals', 'gyp')
+
+# Ensure we import our current gyp source's module, not any version
+# pre-installed in your PYTHONPATH.
+sys.path.insert(0, os.path.join(GYP_SOURCE_DIR, 'pylib'))
+
+import gyp
+
+def main(target_dir, target_file, skia_arch_type, have_neon):
+  """
+  Create gypd files based on target_file.
+  @param target_dir Directory containing all gyp files, including common.gypi
+  @param target_file Gyp file to start on. Other files within target_dir will
+                     be read if target_file depends on them.
+  @param skia_arch_type Target architecture to pass to gyp.
+  @param have_neon Whether to generate files including neon optimizations.
+                   Only meaningful if skia_arch_type is 'arm'.
+  @return path Path to root gypd file created by running gyp.
+  """
+  # Set GYP_DEFINES for building for the android framework.
+  gyp_defines = ('skia_android_framework=1 OS=android skia_arch_type=%s '
+                 % skia_arch_type)
+  if skia_arch_type == 'arm':
+    # Always use thumb and version 7 for arm
+    gyp_defines += 'arm_thumb=1 arm_version=7 '
+    if have_neon:
+      gyp_defines += 'arm_neon=1 '
+    else:
+      gyp_defines += 'arm_neon=0 '
+
+  os.environ['GYP_DEFINES'] = gyp_defines
+
+  args = []
+  args.extend(['--depth', '.'])
+  full_path = os.path.join(target_dir, target_file)
+  args.extend([full_path])
+  # Common conditions
+  args.extend(['-I', os.path.join(target_dir, 'common.gypi')])
+  # Use the debugging format. We'll use these to create one master make file.
+  args.extend(['-f', 'gypd'])
+
+  # Off we go...
+  ret = gyp.main(args)
+
+  if ret != 0:
+    raise Exception("gyp failed!")
+
+  # Running gyp should have created a gypd file, with the same name as
+  # full_path but with a 'd' on the end.
+  gypd_file = full_path + 'd'
+  if not os.path.exists(gypd_file):
+    raise Exception("gyp failed to produce gypd file!")
+
+  return gypd_file
diff --git a/platform_tools/android/bin/gyp_to_android.py b/platform_tools/android/bin/gyp_to_android.py
new file mode 100644
index 0000000000..7990ae9d8b
--- /dev/null
+++ b/platform_tools/android/bin/gyp_to_android.py
@@ -0,0 +1,134 @@
+#!/usr/bin/python
+
+# Copyright 2014 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+Script for generating the Android framework's version of Skia from gyp
+files.
+"""
+
+import android_framework_gyp
+import os
+import shutil
+import sys
+import tempfile
+
+# Find the top of trunk
+SCRIPT_DIR = os.path.abspath(os.path.dirname(__file__))
+SKIA_DIR = os.path.normpath(os.path.join(SCRIPT_DIR, os.pardir, os.pardir,
+                                         os.pardir))
+
+# Find the directory with our helper files, and add it to the path.
+GYP_GEN_DIR = os.path.join(SKIA_DIR, 'platform_tools', 'android', 'gyp_gen')
+sys.path.append(GYP_GEN_DIR)
+
+import gypd_parser
+import makefile_writer
+import variables
+import vars_dict_lib
+
+# Folder containing all gyp files and generated gypd files.
+GYP_FOLDER = 'gyp'
+
+def clean_gypd_files(folder):
+  """
+  Remove the gypd files generated by android_framework_gyp.main().
+  @param folder Folder in which to delete all files ending with 'gypd'.
+  """
+  assert os.path.isdir(folder)
+  files = os.listdir(folder)
+  for f in files:
+    if f.endswith('gypd'):
+      os.remove(os.path.join(folder, f))
+
+def generate_var_dict(target_dir, target_file, skia_arch_type, have_neon):
+  """
+  Create a VarsDict for a particular arch type. Each paramater is passed
+  directly to android_framework_gyp.main().
+  @param target_dir Directory containing gyp files.
+  @param target_file Target gyp file.
+  @param skia_arch_type Target architecture.
+  @param have_neon Whether the target should build for neon.
+  @return a VarsDict containing the variable definitions determined by gyp.
+  """
+  result_file = android_framework_gyp.main(target_dir, target_file,
+                                           skia_arch_type, have_neon)
+  var_dict = vars_dict_lib.VarsDict()
+  gypd_parser.parse_gypd(var_dict, result_file)
+  clean_gypd_files(target_dir)
+  print '.',
+  return var_dict
+
+def main(target_dir=None):
+  """
+  Read gyp files and create Android.mk for the Android framework's
+  external/skia.
+  @param target_dir Directory in which to place 'Android.mk'. If None, the file
+                    will be placed in skia's root directory.
+  """
+  # Create a temporary folder to hold gyp and gypd files. Create it in SKIA_DIR
+  # so that it is a sibling of gyp/, so the relationships between gyp files and
+  # other files (e.g. platform_tools/android/gyp/dependencies.gypi, referenced
+  # by android_deps.gyp as a relative path) is unchanged.
+  # Use mkdtemp to find an unused folder name, but then delete it so copytree
+  # can be called with a non-existent directory.
+  tmp_folder = tempfile.mkdtemp(dir=SKIA_DIR)
+  os.rmdir(tmp_folder)
+  shutil.copytree(os.path.join(SKIA_DIR, GYP_FOLDER), tmp_folder)
+
+  try:
+    main_gyp_file = 'android_framework_lib.gyp'
+
+    print 'Creating Android.mk',
+
+    # Generate a separate VarsDict for each architecture type.  For each
+    # archtype:
+    # 1. call android_framework_gyp.main() to generate gypd files
+    # 2. call parse_gypd to read those gypd files into the VarsDict
+    # 3. delete the gypd files
+    #
+    # Once we have the VarsDict for each architecture type, we combine them all
+    # into a single Android.mk file, which can build targets of any
+    # architecture type.
+
+    # The default uses a non-existant archtype, to find all the general
+    # variable definitions.
+    default_var_dict = generate_var_dict(tmp_folder, main_gyp_file, 'other',
+                                         False)
+    arm_var_dict = generate_var_dict(tmp_folder, main_gyp_file, 'arm', False)
+    arm_neon_var_dict = generate_var_dict(tmp_folder, main_gyp_file, 'arm',
+                                          True)
+    if variables.INCLUDE_X86_OPTS:
+      x86_var_dict = generate_var_dict(tmp_folder, main_gyp_file, 'x86', False)
+    else:
+      x86_var_dict = None
+
+    # Compute the intersection of all targets. All the files in the intersection
+    # should be part of the makefile always. Each dict will now contain trimmed
+    # lists containing only variable definitions specific to that configuration.
+    var_dict_list = [default_var_dict, arm_var_dict, arm_neon_var_dict]
+    if variables.INCLUDE_X86_OPTS:
+      var_dict_list.append(x86_var_dict)
+    common = vars_dict_lib.intersect(var_dict_list)
+
+    # Further trim arm_neon_var_dict with arm_var_dict. After this call,
+    # arm_var_dict (which will now be the intersection) includes all definitions
+    # used by both arm and arm + neon, and arm_neon_var_dict will only contain
+    # those specific to arm + neon.
+    arm_var_dict = vars_dict_lib.intersect([arm_var_dict, arm_neon_var_dict])
+
+    makefile_writer.write_android_mk(target_dir=target_dir,
+                                     common=common,
+                                     arm=arm_var_dict,
+                                     arm_neon=arm_neon_var_dict,
+                                     x86=x86_var_dict,
+                                     default=default_var_dict)
+
+  finally:
+    shutil.rmtree(tmp_folder)
+
+if __name__ == '__main__':
+  main()
diff --git a/platform_tools/android/gyp_gen/gypd_parser.py b/platform_tools/android/gyp_gen/gypd_parser.py
new file mode 100644
index 0000000000..b547c42525
--- /dev/null
+++ b/platform_tools/android/gyp_gen/gypd_parser.py
@@ -0,0 +1,122 @@
+#!/usr/bin/python
+
+# Copyright 2014 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+Functions for parsing the gypd output from gyp.
+"""
+
+import vars_dict_lib
+
+def parse_dictionary(var_dict, d, current_target_name):
+  """
+  Helper function to get the meaningful entries in a dictionary.
+  @param var_dict VarsDict object for storing the results of the parsing.
+  @param d Dictionary object to parse.
+  @param current_target_name The current target being parsed. If this
+                             dictionary is a target, this will be its entry
+                             'target_name'. Otherwise, this will be the name of
+                             the target which contains this dictionary.
+  """
+  for source in d.get('sources', []):
+    # Compare against a lowercase version, in case files are named .H or .GYPI
+    lowercase_source = source.lower()
+    if lowercase_source.endswith('.h'):
+      # Android.mk does not need the header files.
+      continue
+    if lowercase_source.endswith('gypi'):
+      # The gypi files are included in sources, but the sources they included
+      # are also included. No need to parse them again.
+      continue
+    # The path is relative to the gyp folder, but Android wants the path
+    # relative to the root.
+    source = source.replace('../src', 'src', 1)
+    var_dict.LOCAL_SRC_FILES.add(source)
+
+  for lib in d.get('libraries', []):
+    if lib.endswith('.a'):
+      # Remove the '.a'
+      lib = lib[:-2]
+      # Add 'lib', if necessary
+      if not lib.startswith('lib'):
+        lib = 'lib' + lib
+      var_dict.LOCAL_STATIC_LIBRARIES.add(lib)
+    else:
+      # lib will be in the form of '-l<name>'. Change it to 'lib<name>'
+      lib = lib.replace('-l', 'lib', 1)
+      var_dict.LOCAL_SHARED_LIBRARIES.add(lib)
+
+  for dependency in d.get('dependencies', []):
+    # Each dependency is listed as
+    #   <path_to_file>:<target>#target
+    li = dependency.split(':')
+    assert(len(li) <= 2 and len(li) >= 1)
+    sub_targets = []
+    if len(li) == 2 and li[1] != '*':
+      sub_targets.append(li[1].split('#')[0])
+    sub_path = li[0]
+    assert(sub_path.endswith('.gyp'))
+    # Although the original reference is to a .gyp, parse the corresponding
+    # gypd file, which was constructed by gyp.
+    sub_path = sub_path + 'd'
+    parse_gypd(var_dict, sub_path, sub_targets)
+
+  if 'default_configuration' in d:
+    config_name = d['default_configuration']
+    # default_configuration is meaningless without configurations
+    assert('configurations' in d)
+    config = d['configurations'][config_name]
+    parse_dictionary(var_dict, config, current_target_name)
+
+  for flag in d.get('cflags', []):
+    var_dict.LOCAL_CFLAGS.add(flag)
+  for flag in d.get('cflags_cc', []):
+    var_dict.LOCAL_CPPFLAGS.add(flag)
+
+  for include in d.get('include_dirs', []):
+    # The input path will be relative to gyp/, but Android wants relative to
+    # LOCAL_PATH
+    include = include.replace('..', '$(LOCAL_PATH)', 1)
+    # Remove a trailing slash, if present.
+    if include.endswith('/'):
+      include = include[:-1]
+    var_dict.LOCAL_C_INCLUDES.add(include)
+    # For the top level, libskia, include directories should be exported.
+    if current_target_name == 'libskia':
+      var_dict.LOCAL_EXPORT_C_INCLUDE_DIRS.add(include)
+
+  for define in d.get('defines', []):
+    var_dict.LOCAL_CFLAGS.add('-D' + define)
+
+
+def parse_gypd(var_dict, path, desired_targets=None):
+  """
+  Parse a gypd file.
+  @param var_dict VarsDict object for storing the result of the parse.
+  @param path Path to gypd file.
+  @param desired_targets List of targets to be parsed from this file. If empty,
+                         parse all targets.
+  """
+  d = {}
+  with open(path, 'r') as f:
+    # Read the entire file as a dictionary
+    d = eval(f.read())
+
+  # The gypd file is structured such that the top level dictionary has an entry
+  # named 'targets'
+  for target in d['targets']:
+    target_name = target['target_name']
+    if target_name in var_dict.KNOWN_TARGETS:
+      # Avoid circular dependencies
+      continue
+    if desired_targets and target_name not in desired_targets:
+      # Our caller does not depend on this one
+      continue
+    # Add it to our known targets so we don't parse it again
+    var_dict.KNOWN_TARGETS.add(target_name)
+
+    parse_dictionary(var_dict, target, target_name)
+
diff --git a/platform_tools/android/gyp_gen/makefile_writer.py b/platform_tools/android/gyp_gen/makefile_writer.py
new file mode 100644
index 0000000000..ea3a27ff1e
--- /dev/null
+++ b/platform_tools/android/gyp_gen/makefile_writer.py
@@ -0,0 +1,175 @@
+#!/usr/bin/python
+
+# Copyright 2014 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+Functions for creating an Android.mk from already created dictionaries.
+"""
+
+import os
+import variables
+
+def write_group(f, name, items, append):
+  """
+  Helper function to list all names passed to a variable.
+  @param f File open for writing (Android.mk)
+  @param name Name of the makefile variable (e.g. LOCAL_CFLAGS)
+  @param items list of strings to be passed to the variable.
+  @param append Whether to append to the variable or overwrite it.
+  """
+  if not items:
+    return
+
+  # Copy the list so we can prepend it with its name.
+  items_to_write = list(items)
+
+  if append:
+    items_to_write.insert(0, '%s +=' % name)
+  else:
+    items_to_write.insert(0, '%s :=' % name)
+
+  f.write(' \\\n\t'.join(items_to_write))
+
+  f.write('\n\n')
+
+
+def write_local_vars(f, var_dict, append):
+  """
+  Helper function to write all the members of var_dict to the makefile.
+  @param f File open for writing (Android.mk)
+  @param var_dict VarsDict holding the unique values for one configuration.
+  @param append Whether to append to each makefile variable or overwrite it.
+  """
+  for key in var_dict.keys():
+    if key == 'LOCAL_CFLAGS':
+      # Always append LOCAL_CFLAGS. This allows us to define some early on in
+      # the makefile and not overwrite them.
+      _append = True
+    elif key == 'KNOWN_TARGETS':
+      # KNOWN_TARGETS are not needed in the final make file.
+      continue
+    else:
+      _append = append
+    write_group(f, key, var_dict[key], _append)
+
+
+AUTOGEN_WARNING = (
+"""
+###############################################################################
+#
+# THIS FILE IS AUTOGENERATED BY GYP_TO_ANDROID.PY. DO NOT EDIT.
+#
+###############################################################################
+
+"""
+)
+
+
+DEBUGGING_HELP = (
+"""
+###############################################################################
+#
+# PROBLEMS WITH SKIA DEBUGGING?? READ THIS...
+#
+# The debug build results in changes to the Skia headers. This means that those
+# using libskia must also be built with the debug version of the Skia headers.
+# There are a few scenarios where this comes into play:
+#
+# (1) You're building debug code that depends on libskia.
+#   (a) If libskia is built in release, then define SK_RELEASE when building
+#       your sources.
+#   (b) If libskia is built with debugging (see step 2), then no changes are
+#       needed since your sources and libskia have been built with SK_DEBUG.
+# (2) You're building libskia in debug mode.
+#   (a) RECOMMENDED: You can build the entire system in debug mode. Do this by
+#       updating your build/config.mk to include -DSK_DEBUG on the line that
+#       defines COMMON_GLOBAL_CFLAGS
+#   (b) You can update all the users of libskia to define SK_DEBUG when they are
+#       building their sources.
+#
+# NOTE: If neither SK_DEBUG or SK_RELEASE are defined then Skia checks NDEBUG to
+#       determine which build type to use.
+###############################################################################
+
+"""
+)
+
+
+# TODO (scroggo): Currently write_android_mk has intimate knowledge about its
+# parameters: e.g. arm_neon keeps track of differences from arm, whereas the
+# others keep track of differences from common. Consider reworking this.
+def write_android_mk(target_dir, common, arm, arm_neon, x86, default):
+  """
+  Given all the variables, write the final make file.
+  @param target_dir The full path to the directory to write Android.mk, or None
+                    to use the current working directory.
+  @param common VarsDict holding variables definitions common to all
+                configurations.
+  @param arm VarsDict holding variable definitions unique to arm. Will be
+             written to the makefile inside an 'ifeq ($(TARGET_ARCH), arm)'
+             block.
+  @param arm_neon VarsDict holding variable definitions unique to arm with neon.
+                 Will be written inside an 'ifeq ($(ARCH_ARM_HAVE_NEON),true)'
+                 block nested inside an 'ifeq ($(TARGET_ARCH), arm)' block.
+  @param x86 VarsDict holding variable definitions unique to x86. Will be
+             written inside an 'ifeq ($(TARGET_ARCH),x86)' block.
+  @param default VarsDict holding variable definitions for an architecture
+                 without custom optimizations.
+  TODO: Add mips.
+  """
+  target_file = 'Android.mk'
+  if target_dir:
+    target_file = os.path.join(target_dir, target_file)
+  with open(target_file, 'w') as f:
+    f.write(AUTOGEN_WARNING)
+    f.write('BASE_PATH := $(call my-dir)\n')
+    f.write('LOCAL_PATH:= $(call my-dir)\n')
+
+    f.write(DEBUGGING_HELP)
+
+    f.write('include $(CLEAR_VARS)\n')
+
+    f.write('LOCAL_ARM_MODE := thumb\n')
+
+    # need a flag to tell the C side when we're on devices with large memory
+    # budgets (i.e. larger than the low-end devices that initially shipped)
+    f.write('ifeq ($(ARCH_ARM_HAVE_VFP),true)\n')
+    f.write('\tLOCAL_CFLAGS += -DANDROID_LARGE_MEMORY_DEVICE\n')
+    f.write('endif\n\n')
+
+    f.write('ifeq ($(TARGET_ARCH),x86)\n')
+    f.write('\tLOCAL_CFLAGS += -DANDROID_LARGE_MEMORY_DEVICE\n')
+    f.write('endif\n\n')
+
+    f.write('# used for testing\n')
+    f.write('#LOCAL_CFLAGS += -g -O0\n\n')
+
+    f.write('ifeq ($(NO_FALLBACK_FONT),true)\n')
+    f.write('\tLOCAL_CFLAGS += -DNO_FALLBACK_FONT\n')
+    f.write('endif\n\n')
+
+    write_local_vars(f, common, False)
+
+    f.write('ifeq ($(TARGET_ARCH),arm)\n')
+    f.write('ifeq ($(ARCH_ARM_HAVE_NEON),true)\n')
+    write_local_vars(f, arm_neon, True)
+    f.write('endif\n\n')
+    write_local_vars(f, arm, True)
+
+    if variables.INCLUDE_X86_OPTS:
+      f.write('else ifeq ($(TARGET_ARCH),x86)\n')
+      write_local_vars(f, x86, True)
+
+    f.write('else\n')
+    write_local_vars(f, default, True)
+    f.write('endif\n\n')
+
+    f.write('include external/stlport/libstlport.mk\n')
+    f.write('LOCAL_MODULE:= libskia\n')
+    f.write('include $(BUILD_SHARED_LIBRARY)\n')
+
+
+
diff --git a/platform_tools/android/gyp_gen/variables.py b/platform_tools/android/gyp_gen/variables.py
new file mode 100644
index 0000000000..326254a86e
--- /dev/null
+++ b/platform_tools/android/gyp_gen/variables.py
@@ -0,0 +1,11 @@
+#!/usr/bin/python
+
+# Copyright 2014 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# TODO (scroggo): Currently the x86 specific files are not included. Include
+# them.
+INCLUDE_X86_OPTS = False
+
diff --git a/platform_tools/android/gyp_gen/vars_dict_lib.py b/platform_tools/android/gyp_gen/vars_dict_lib.py
new file mode 100644
index 0000000000..eedb8a36b9
--- /dev/null
+++ b/platform_tools/android/gyp_gen/vars_dict_lib.py
@@ -0,0 +1,133 @@
+#!/usr/bin/python
+
+# Copyright 2014 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import collections
+import types
+
+class OrderedSet(object):
+  """
+  Ordered set of unique items that supports addition and removal.
+  """
+
+  def __init__(self):
+    self.__li = []
+
+  def add(self, item):
+    """
+    Add item, if it is not already in the set.
+    @param item The item to add.
+    """
+    if item not in self.__li:
+      self.__li.append(item)
+
+  def __contains__(self, item):
+    """
+    Whether the set contains item.
+    @param item The item to search for in the set.
+    @return bool Whether the item is in the set.
+    """
+    return item in self.__li
+
+  def __iter__(self):
+    """
+    Iterator for the set.
+    """
+    return self.__li.__iter__()
+
+  def remove(self, item):
+    """
+    Remove item from the set.
+    @param item Item to be removed.
+    """
+    return self.__li.remove(item)
+
+  def __len__(self):
+    """
+    Number of items in the set.
+    """
+    return len(self.__li)
+
+  def __getitem__(self, index):
+    """
+    Return item at index.
+    """
+    return self.__li[index]
+
+VAR_NAMES = ['LOCAL_CFLAGS',
+             'LOCAL_CPPFLAGS',
+             'LOCAL_SRC_FILES',
+             'LOCAL_SHARED_LIBRARIES',
+             'LOCAL_STATIC_LIBRARIES',
+             'LOCAL_C_INCLUDES',
+             'LOCAL_EXPORT_C_INCLUDE_DIRS',
+             'KNOWN_TARGETS']
+
+class VarsDict(collections.namedtuple('VarsDict', VAR_NAMES)):
+  """
+  Custom class for storing the arguments to Android.mk variables. Can be
+  treated as a dictionary with fixed keys.
+  """
+
+  __slots__ = ()
+
+  def __new__(cls):
+    lists = []
+    # TODO (scroggo): Is there a better way add N items?
+    for __unused__ in range(len(VAR_NAMES)):
+      lists.append(OrderedSet())
+    return tuple.__new__(cls, lists)
+
+  def keys(self):
+    """
+    Return the field names as strings.
+    """
+    return self._fields
+
+  def __getitem__(self, index):
+    """
+    Return an item, indexed by a number or a string.
+    """
+    if type(index) == types.IntType:
+      # Treat the index as an array index into a tuple.
+      return tuple.__getitem__(self, index)
+    if type(index) == types.StringType:
+      # Treat the index as a key into a dictionary.
+      return eval('self.%s' % index)
+    return None
+
+
+def intersect(var_dict_list):
+  """
+  Find the intersection of a list of VarsDicts and trim each input to its
+  unique entries.
+  @param var_dict_list list of VarsDicts. WARNING: each VarsDict will be
+                       modified in place, to remove the common elements!
+  @return VarsDict containing list entries common to all VarsDicts in
+          var_dict_list
+  """
+  intersection = VarsDict()
+  # First VarsDict
+  var_dict_a = var_dict_list[0]
+  # The rest.
+  other_var_dicts = var_dict_list[1:]
+
+  for key in var_dict_a.keys():
+    # Copy A's list, so we can continue iterating after modifying the original.
+    a_list = list(var_dict_a[key])
+    for item in a_list:
+      # If item is in all lists, add to intersection, and remove from all.
+      in_all_lists = True
+      for var_dict in other_var_dicts:
+        if not item in var_dict[key]:
+          in_all_lists = False
+          break
+      if in_all_lists:
+        intersection[key].add(item)
+        for var_dict in var_dict_list:
+          var_dict[key].remove(item)
+  return intersection
+
diff --git a/platform_tools/android/tests/gyp_to_android_tests.py b/platform_tools/android/tests/gyp_to_android_tests.py
new file mode 100644
index 0000000000..cb2a3e0c8c
--- /dev/null
+++ b/platform_tools/android/tests/gyp_to_android_tests.py
@@ -0,0 +1,105 @@
+#!/usr/bin/python
+
+# Copyright 2014 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+Test gyp_to_android.py
+"""
+
+import os
+import shutil
+import sys
+import tempfile
+import test_variables
+import unittest
+
+# Path to gyp_to_android
+sys.path.append(test_variables.BIN_DIR)
+
+import gyp_to_android
+
+class AndroidMkCreationTest(unittest.TestCase):
+
+  def setUp(self):
+    # Create a temporary directory for storing the output (Android.mk)
+    self.__tmp_dir = tempfile.mkdtemp()
+
+  def test_create(self):
+    gyp_to_android.main(self.__tmp_dir)
+
+    # Now there should be a file named 'Android.mk' inside __tmp_dir
+    path_to_android_mk = os.path.join(self.__tmp_dir, 'Android.mk')
+    self.assertTrue(os.path.exists(path_to_android_mk))
+
+  def tearDown(self):
+    # Remove self.__tmp_dir, which is no longer needed.
+    shutil.rmtree(self.__tmp_dir)
+
+
+GYPD_SUFFIX = ".gypd"
+GYP_SUFFIX = ".gyp"
+GYPI_SUFFIX = ".gypi"
+OTHER_SUFFIX = ".txt"
+
+class CleanGypdTest(unittest.TestCase):
+
+  def setUp(self):
+    self.__tmp_dir = tempfile.mkdtemp()
+    self.__num_files = 10
+    # Fill the dir with four types of files. .gypd files should be deleted by
+    # clean_gypd_files(), while the rest should be left alone.
+    for i in range(self.__num_files):
+      self.create_file('%s%s' % (str(i), GYPD_SUFFIX))
+      self.create_file('%s%s' % (str(i), GYPI_SUFFIX))
+      self.create_file('%s%s' % (str(i), GYP_SUFFIX))
+      self.create_file('%s%s' % (str(i), OTHER_SUFFIX))
+
+  def create_file(self, basename):
+    """
+    Create a file named 'basename' in self.__tmp_dir.
+    """
+    f = tempfile.mkstemp(dir=self.__tmp_dir)
+    os.rename(f[1], os.path.join(self.__tmp_dir, basename))
+    self.assert_file_exists(basename)
+
+  def assert_file_exists(self, basename):
+    """
+    Assert that 'basename' exists in self.__tmp_dir.
+    """
+    full_name = os.path.join(self.__tmp_dir, basename)
+    self.assertTrue(os.path.exists(full_name))
+
+  def assert_file_does_not_exist(self, basename):
+    """
+    Assert that 'basename' does not exist in self.__tmp_dir.
+    """
+    full_name = os.path.join(self.__tmp_dir, basename)
+    self.assertFalse(os.path.exists(full_name))
+
+  def test_clean(self):
+    """
+    Test that clean_gypd_files() deletes .gypd files, and leaves others.
+    """
+    gyp_to_android.clean_gypd_files(self.__tmp_dir)
+    for i in range(self.__num_files):
+      self.assert_file_exists('%s%s' % (str(i), GYPI_SUFFIX))
+      self.assert_file_exists('%s%s' % (str(i), GYP_SUFFIX))
+      self.assert_file_exists('%s%s' % (str(i), OTHER_SUFFIX))
+      # Only the GYPD files should have been deleted.
+      self.assert_file_does_not_exist('%s%s' % (str(i), GYPD_SUFFIX))
+
+  def tearDown(self):
+    shutil.rmtree(self.__tmp_dir)
+
+
+def main():
+  loader = unittest.TestLoader()
+  suite = loader.loadTestsFromTestCase(AndroidMkCreationTest)
+  suite.addTest(loader.loadTestsFromTestCase(CleanGypdTest))
+  unittest.TextTestRunner(verbosity=2).run(suite)
+
+if __name__ == "__main__":
+  main()
diff --git a/platform_tools/android/tests/ordered_set_tests.py b/platform_tools/android/tests/ordered_set_tests.py
new file mode 100644
index 0000000000..248f0f6f6c
--- /dev/null
+++ b/platform_tools/android/tests/ordered_set_tests.py
@@ -0,0 +1,69 @@
+#!/usr/bin/python
+
+# Copyright 2014 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+Test OrderedSet.
+"""
+
+import sys
+import test_variables
+import unittest
+
+sys.path.append(test_variables.GYP_GEN_DIR)
+
+from vars_dict_lib import OrderedSet
+
+
+def create_dummy_var(i):
+  return 'dummy_var' + str(i)
+
+
+class OrderedSetTest(unittest.TestCase):
+
+  def setUp(self):
+    self.__set = OrderedSet()
+
+  def test_methods(self):
+    """
+    Test methods on OrderedSet.
+    """
+    RANGE = 10
+    for i in range(RANGE):
+      dummy_var = create_dummy_var(i)
+      # Add to the list. This should succeed.
+      self.__set.add(dummy_var)
+      self.assertEqual(len(self.__set), i+1)
+      self.assertTrue(dummy_var in self.__set)
+      self.assertEqual(self.__set[i], dummy_var)
+
+      # Now attempt to add it again. This should fail.
+      self.__set.add(dummy_var)
+      self.assertEqual(len(self.__set), i+1)
+      self.assertEqual(self.__set[i], dummy_var)
+
+    # Test iterator.
+    counter = 0
+    for set_member in self.__set:
+      self.assertEqual(create_dummy_var(counter), set_member)
+      counter += 1
+    self.assertEqual(counter, len(self.__set))
+
+    # Now test removal.
+    for i in range(RANGE):
+      dummy_var = create_dummy_var(i)
+      self.__set.remove(dummy_var)
+      self.assertEqual(len(self.__set), RANGE-i-1)
+      self.assertFalse(dummy_var in self.__set)
+
+def main():
+  loader = unittest.TestLoader()
+  suite = loader.loadTestsFromTestCase(OrderedSetTest)
+  unittest.TextTestRunner(verbosity=2).run(suite)
+
+if __name__ == "__main__":
+  main()
+
diff --git a/platform_tools/android/tests/run_all.py b/platform_tools/android/tests/run_all.py
new file mode 100644
index 0000000000..317ee759db
--- /dev/null
+++ b/platform_tools/android/tests/run_all.py
@@ -0,0 +1,24 @@
+#!/usr/bin/python
+
+# Copyright 2014 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+Run all the tests in platform_tools/android/tests.
+"""
+
+import os
+import unittest
+
+def main():
+  suite = unittest.TestLoader().discover(os.path.dirname(__file__),
+                                         pattern='*_tests.py')
+  results = unittest.TextTestRunner(verbosity=2).run(suite)
+  print repr(results)
+  if not results.wasSuccessful():
+    raise Exception('failed one or more unittests')
+
+if __name__ == '__main__':
+  main()
diff --git a/platform_tools/android/tests/test_variables.py b/platform_tools/android/tests/test_variables.py
new file mode 100644
index 0000000000..dd49a7e4e9
--- /dev/null
+++ b/platform_tools/android/tests/test_variables.py
@@ -0,0 +1,22 @@
+#!/usr/bin/python
+
+# Copyright 2014 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+Common variables for tests.
+"""
+
+import os
+
+# Find this file so we can find the python files to test.
+SCRIPT_DIR = os.path.dirname(__file__)
+ANDROID_DIR = os.path.normpath(os.path.join(SCRIPT_DIR, os.pardir))
+
+# Path to gyp_to_android.
+BIN_DIR = os.path.join(ANDROID_DIR, 'bin')
+
+# Path to generator files.
+GYP_GEN_DIR = os.path.join(ANDROID_DIR, 'gyp_gen')
diff --git a/platform_tools/android/tests/var_dict_tests.py b/platform_tools/android/tests/var_dict_tests.py
new file mode 100644
index 0000000000..8cd9677068
--- /dev/null
+++ b/platform_tools/android/tests/var_dict_tests.py
@@ -0,0 +1,110 @@
+#!/usr/bin/python
+
+# Copyright 2014 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+Test the VarsDict.
+"""
+
+import sys
+import test_variables
+import unittest
+
+sys.path.append(test_variables.GYP_GEN_DIR)
+
+import vars_dict_lib
+from vars_dict_lib import OrderedSet
+from vars_dict_lib import VarsDict
+from vars_dict_lib import VAR_NAMES
+
+class VarsDictTest(unittest.TestCase):
+  """
+  Tests for the VarsDict class.
+  """
+
+  # May not be needed.
+  def setUp(self):
+    self.__vars_dict = VarsDict()
+
+  def assert_consistency(self, v_dict):
+    self.assertIs(v_dict.LOCAL_CFLAGS, v_dict['LOCAL_CFLAGS'])
+    self.assertIs(v_dict.LOCAL_CPPFLAGS, v_dict['LOCAL_CPPFLAGS'])
+    self.assertIs(v_dict.LOCAL_SRC_FILES, v_dict['LOCAL_SRC_FILES'])
+    self.assertIs(v_dict.LOCAL_SHARED_LIBRARIES,
+                  v_dict['LOCAL_SHARED_LIBRARIES'])
+    self.assertIs(v_dict.LOCAL_STATIC_LIBRARIES,
+                  v_dict['LOCAL_STATIC_LIBRARIES'])
+    self.assertIs(v_dict.LOCAL_C_INCLUDES, v_dict['LOCAL_C_INCLUDES'])
+    self.assertIs(v_dict.LOCAL_EXPORT_C_INCLUDE_DIRS,
+                  v_dict['LOCAL_EXPORT_C_INCLUDE_DIRS'])
+    self.assertIs(v_dict.KNOWN_TARGETS, v_dict['KNOWN_TARGETS'])
+
+  def test_creation(self):
+    v_dict = VarsDict()
+    # VarsDict has one entry for each label in VAR_NAMES
+    self.assertEqual(len(v_dict.keys()), len(VAR_NAMES))
+    for key in v_dict.keys():
+      self.assertIn(key, VAR_NAMES)
+      # Each entry is an empty OrderedSet
+      self.assertIsNotNone(v_dict[key])
+      self.assertIsInstance(v_dict[key], OrderedSet)
+      self.assertEqual(len(v_dict[key]), 0)
+      self.assert_consistency(v_dict)
+
+  def test_intersection(self):
+    v_dict_list = []
+    RANGE = 10
+    for i in range(RANGE):
+      v_dict = VarsDict()
+      # Add something common to each field, as well as a unique entry
+      v_dict.LOCAL_CFLAGS.add('cflag')
+      v_dict.LOCAL_CFLAGS.add(str(i))
+
+      v_dict.LOCAL_CPPFLAGS.add('cppflag')
+      v_dict.LOCAL_CPPFLAGS.add(str(i))
+
+      v_dict.LOCAL_SRC_FILES.add('src')
+      v_dict.LOCAL_SRC_FILES.add(str(i))
+
+      v_dict.LOCAL_SHARED_LIBRARIES.add('shared')
+      v_dict.LOCAL_SHARED_LIBRARIES.add(str(i))
+
+      v_dict.LOCAL_STATIC_LIBRARIES.add('static')
+      v_dict.LOCAL_STATIC_LIBRARIES.add(str(i))
+
+      v_dict.LOCAL_C_INCLUDES.add('includes')
+      v_dict.LOCAL_C_INCLUDES.add(str(i))
+
+      v_dict.LOCAL_EXPORT_C_INCLUDE_DIRS.add('exports')
+      v_dict.LOCAL_EXPORT_C_INCLUDE_DIRS.add(str(i))
+
+      v_dict.KNOWN_TARGETS.add('known')
+      v_dict.KNOWN_TARGETS.add(str(i))
+
+      self.assert_consistency(v_dict)
+
+      v_dict_list.append(v_dict)
+
+    intersection = vars_dict_lib.intersect(v_dict_list)
+
+    self.assert_consistency(intersection)
+
+    for key in intersection.keys():
+      # Each field had one common item
+      self.assertEqual(len(intersection[key]), 1)
+      for item in intersection[key]:
+        for other_v_dict in v_dict_list:
+          self.assertNotIn(item, other_v_dict[key])
+
+
+def main():
+  loader = unittest.TestLoader()
+  suite = loader.loadTestsFromTestCase(VarsDictTest)
+  unittest.TextTestRunner(verbosity=2).run(suite)
+
+if __name__ == "__main__":
+  main()
+