[Android] Refactor md5_check + add tests

This adds a function md5_check.CallAndRecordIfStale that makes the
common (and currently only) use of Md5Checker much simpler (i.e just
call this function). All the users of md5_check are updated to use this
function, and everything else in md5_check is no longer part of the
public API.

Also, adds tests for the md5_check module. These are only run manually currently.

BUG=158821

Review URL: https://codereview.chromium.org/14263006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@194377 0039d316-1c4b-4281-b951-d872f2087c98

9 files changed, 158 insertions, 66 deletions

diff --git a/build/android/gyp/apk_install.py b/build/android/gyp/apk_install.py
index f8e7caa..8f1e69b 100755
--- a/build/android/gyp/apk_install.py
+++ b/build/android/gyp/apk_install.py
@@ -38,13 +38,12 @@ def main(argv):
       options.apk_path]
 
   serial_number = android_commands.AndroidCommands().Adb().GetSerialNumber()
-  md5_stamp = '%s.%s.md5' % (options.apk_path, serial_number)
-
-  md5_checker = md5_check.Md5Checker(
-      stamp=md5_stamp, inputs=[options.apk_path], command=install_cmd)
-  if md5_checker.IsStale():
-    build_utils.CheckCallDie(install_cmd)
-    md5_checker.Write()
+  record_path = '%s.%s.md5.stamp' % (options.apk_path, serial_number)
+  md5_check.CallAndRecordIfStale(
+      lambda: build_utils.CheckCallDie(install_cmd),
+      record_path=record_path,
+      input_paths=[options.apk_path],
+      input_strings=install_cmd)
 
   if options.stamp:
     build_utils.Touch(options.stamp)
diff --git a/build/android/gyp/create_device_library_links.py b/build/android/gyp/create_device_library_links.py
index e71f727..48aa61e 100755
--- a/build/android/gyp/create_device_library_links.py
+++ b/build/android/gyp/create_device_library_links.py
@@ -47,14 +47,16 @@ def CreateLinks(options):
   serial_number = adb.Adb().GetSerialNumber()
   for lib in libraries:
     host_path = os.path.join(options.libraries_dir, lib)
-
-    md5_stamp = '%s.%s.link.md5' % (host_path, serial_number)
-    md5_checker = md5_check.Md5Checker(stamp=md5_stamp, inputs=[host_path])
-    if md5_checker.IsStale():
+    def CreateLink():
       link = '/data/data/' + apk_package + '/lib/' + lib
       target = options.target_dir + '/' + lib
       RunLinkCommand(adb, target, link)
-      md5_checker.Write()
+
+    record_path = '%s.%s.link.md5.stamp' % (host_path, serial_number)
+    md5_check.CallAndRecordIfStale(
+        CreateLink,
+        record_path=record_path,
+        input_paths=[host_path])
 
 
 def main(argv):
diff --git a/build/android/gyp/dex.py b/build/android/gyp/dex.py
index 99834c4..84a9c63 100755
--- a/build/android/gyp/dex.py
+++ b/build/android/gyp/dex.py
@@ -17,14 +17,14 @@ def DoDex(options, paths):
   dx_binary = os.path.join(options.android_sdk_root, 'platform-tools', 'dx')
   dex_cmd = [dx_binary, '--dex', '--output', options.dex_path] + paths
 
-  md5_stamp = '%s.md5' % options.dex_path
-  md5_checker = md5_check.Md5Checker(
-      stamp=md5_stamp, inputs=paths, command=dex_cmd)
-  if md5_checker.IsStale():
-    build_utils.CheckCallDie(dex_cmd, suppress_output=True)
-  else:
-    build_utils.Touch(options.dex_path)
-  md5_checker.Write()
+  record_path = '%s.md5.stamp' % options.dex_path
+  md5_check.CallAndRecordIfStale(
+      lambda: build_utils.CheckCallDie(dex_cmd, suppress_output=True),
+      record_path=record_path,
+      input_paths=paths,
+      input_strings=dex_cmd)
+
+  build_utils.Touch(options.dex_path)
 
 
 def main(argv):
diff --git a/build/android/gyp/jar.py b/build/android/gyp/jar.py
index 7618def..6d4fe12 100755
--- a/build/android/gyp/jar.py
+++ b/build/android/gyp/jar.py
@@ -28,15 +28,14 @@ def DoJar(options):
   class_files_rel = [os.path.relpath(f, jar_cwd) for f in class_files]
   jar_cmd = ['jar', 'cf0', jar_path] + class_files_rel
 
-
-  md5_stamp = '%s.md5' % options.jar_path
-  md5_checker = md5_check.Md5Checker(
-      stamp=md5_stamp, inputs=class_files, command=jar_cmd)
-  if md5_checker.IsStale():
-    build_utils.CheckCallDie(jar_cmd, cwd=jar_cwd)
-  else:
-    build_utils.Touch(options.jar_path)
-  md5_checker.Write()
+  record_path = '%s.md5.stamp' % options.jar_path
+  md5_check.CallAndRecordIfStale(
+      lambda: build_utils.CheckCallDie(jar_cmd, cwd=jar_cwd),
+      record_path=record_path,
+      input_paths=class_files,
+      input_strings=jar_cmd)
+
+  build_utils.Touch(options.jar_path)
 
 
 def main(argv):
diff --git a/build/android/gyp/jar_toc.py b/build/android/gyp/jar_toc.py
index b40f43d..9db9d26 100755
--- a/build/android/gyp/jar_toc.py
+++ b/build/android/gyp/jar_toc.py
@@ -81,13 +81,13 @@ def UpdateToc(jar_path, toc_path):
 def DoJarToc(options):
   jar_path = options.jar_path
   toc_path = options.toc_path
-  md5_stamp_path = '%s.md5' % toc_path
-  md5_checker = md5_check.Md5Checker(stamp=md5_stamp_path, inputs=[jar_path])
-  if md5_checker.IsStale():
-    UpdateToc(jar_path, toc_path)
-    md5_checker.Write()
-  else:
-    build_utils.Touch(toc_path)
+  record_path = '%s.md5.stamp' % toc_path
+  md5_check.CallAndRecordIfStale(
+      lambda: UpdateToc(jar_path, toc_path),
+      record_path=record_path,
+      input_paths=[jar_path],
+      )
+  build_utils.Touch(toc_path)
 
 
 def main(argv):
diff --git a/build/android/gyp/javac.py b/build/android/gyp/javac.py
index cbd4293..c117004 100755
--- a/build/android/gyp/javac.py
+++ b/build/android/gyp/javac.py
@@ -52,12 +52,7 @@ def DoJavac(options):
       '-Xlint:deprecation',
       ] + java_files
 
-  md5_stamp = '%s/javac.md5' % options.output_dir
-  md5_checker = md5_check.Md5Checker(
-      stamp=md5_stamp,
-      inputs=java_files + jar_inputs,
-      command=javac_cmd)
-  if md5_checker.IsStale():
+  def Compile():
     # Delete the classes directory. This ensures that all .class files in the
     # output are actually from the input .java files. For example, if a .java
     # file is deleted or an inner class is removed, the classes directory should
@@ -66,7 +61,14 @@ def DoJavac(options):
     build_utils.MakeDirectory(output_dir)
     suppress_output = not options.chromium_code
     build_utils.CheckCallDie(javac_cmd, suppress_output=suppress_output)
-    md5_checker.Write()
+
+  record_path = '%s/javac.md5.stamp' % options.output_dir
+  md5_check.CallAndRecordIfStale(
+      Compile,
+      record_path=record_path,
+      input_paths=java_files + jar_inputs,
+      input_strings=javac_cmd)
+
 
 def main(argv):
   parser = optparse.OptionParser()
diff --git a/build/android/gyp/push_libraries.py b/build/android/gyp/push_libraries.py
index e586d0b..70a1fcb 100755
--- a/build/android/gyp/push_libraries.py
+++ b/build/android/gyp/push_libraries.py
@@ -27,19 +27,21 @@ def DoPush(options):
 
   adb = android_commands.AndroidCommands()
   serial_number = adb.Adb().GetSerialNumber()
-  needs_directory = True
+  # A list so that it is modifiable in Push below.
+  needs_directory = [True]
   for lib in libraries:
     device_path = os.path.join(options.device_dir, lib)
     host_path = os.path.join(options.libraries_dir, lib)
 
-    md5_stamp = '%s.%s.push.md5' % (host_path, serial_number)
-    md5_checker = md5_check.Md5Checker(stamp=md5_stamp, inputs=[host_path])
-    if md5_checker.IsStale():
+    def Push():
       if needs_directory:
         adb.RunShellCommand('mkdir ' + options.device_dir)
-        needs_directory = False
+        needs_directory[:] = [] # = False
       adb.PushIfNeeded(host_path, device_path)
-      md5_checker.Write()
+
+    record_path = '%s.%s.push.md5.stamp' % (host_path, serial_number)
+    md5_check.CallAndRecordIfStale(
+        Push, record_path=record_path, input_paths=[host_path])
 
 
 def main(argv):
diff --git a/build/android/gyp/util/md5_check.py b/build/android/gyp/util/md5_check.py
index 47f1ec9..acf707c 100644
--- a/build/android/gyp/util/md5_check.py
+++ b/build/android/gyp/util/md5_check.py
@@ -6,7 +6,24 @@ import hashlib
 import os
 
 
-def UpdateMd5ForFile(md5, path, block_size=2**16):
+def CallAndRecordIfStale(
+    function, record_path=None, input_paths=[], input_strings=[]):
+  """Calls function if the md5sum of the input paths/strings has changed.
+
+  The md5sum of the inputs is compared with the one stored in record_path. If
+  this has changed (or the record doesn't exist), function will be called and
+  the new md5sum will be recorded.
+  """
+  md5_checker = _Md5Checker(
+      record_path=record_path,
+      input_paths=input_paths,
+      input_strings=input_strings)
+  if md5_checker.IsStale():
+    function()
+    md5_checker.Write()
+
+
+def _UpdateMd5ForFile(md5, path, block_size=2**16):
   with open(path, 'rb') as infile:
     while True:
       data = infile.read(block_size)
@@ -15,38 +32,42 @@ def UpdateMd5ForFile(md5, path, block_size=2**16):
       md5.update(data)
 
 
-def UpdateMd5ForDirectory(md5, dir_path):
+def _UpdateMd5ForDirectory(md5, dir_path):
   for root, _, files in os.walk(dir_path):
     for f in files:
-      UpdateMd5ForFile(md5, os.path.join(root, f))
+      _UpdateMd5ForFile(md5, os.path.join(root, f))
 
 
-def UpdateMd5ForPath(md5, path):
+def _UpdateMd5ForPath(md5, path):
   if os.path.isdir(path):
-    UpdateMd5ForDirectory(md5, path)
+    _UpdateMd5ForDirectory(md5, path)
   else:
-    UpdateMd5ForFile(md5, path)
+    _UpdateMd5ForFile(md5, path)
+
 
+class _Md5Checker(object):
+  def __init__(self, record_path=None, input_paths=[], input_strings=[]):
+    assert record_path.endswith('.stamp'), (
+        'record paths must end in \'.stamp\' so that they are easy to find '
+        'and delete')
 
-class Md5Checker(object):
-  def __init__(self, stamp=None, inputs=[], command=[]):
-    self.stamp = stamp
+    self.record_path = record_path
 
     md5 = hashlib.md5()
-    for i in inputs:
-      UpdateMd5ForPath(md5, i)
-    for s in command:
+    for i in sorted(input_paths):
+      _UpdateMd5ForPath(md5, i)
+    for s in input_strings:
       md5.update(s)
     self.new_digest = md5.hexdigest()
 
     self.old_digest = ''
-    if os.path.exists(stamp):
-      with open(stamp, 'r') as old_stamp:
-        self.old_digest = old_stamp.read()
+    if os.path.exists(self.record_path):
+      with open(self.record_path, 'r') as old_record:
+        self.old_digest = old_record.read()
 
   def IsStale(self):
     return self.old_digest != self.new_digest
 
   def Write(self):
-    with open(self.stamp, 'w') as new_stamp:
-      new_stamp.write(self.new_digest)
+    with open(self.record_path, 'w') as new_record:
+      new_record.write(self.new_digest)
diff --git a/build/android/gyp/util/md5_check_test.py b/build/android/gyp/util/md5_check_test.py
new file mode 100644
index 0000000..a18942e
--- /dev/null
+++ b/build/android/gyp/util/md5_check_test.py
@@ -0,0 +1,67 @@
+# Copyright 2013 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import tempfile
+import unittest
+
+import md5_check
+
+
+class TestMd5Check(unittest.TestCase):
+  def testCallAndRecordIfStale(self):
+    input_strings = ['string1', 'string2']
+    input_file1 = tempfile.NamedTemporaryFile()
+    input_file2 = tempfile.NamedTemporaryFile()
+    file1_contents = 'input file 1'
+    file2_contents = 'input file 2'
+    input_file1.write(file1_contents)
+    input_file1.flush()
+    input_file2.write(file2_contents)
+    input_file2.flush()
+    input_files = [input_file1.name, input_file2.name]
+
+    record_path = tempfile.NamedTemporaryFile(suffix='.stamp')
+
+    def CheckCallAndRecord(should_call, message):
+      self.called = False
+      def MarkCalled():
+        self.called = True
+      md5_check.CallAndRecordIfStale(
+          MarkCalled,
+          record_path=record_path.name,
+          input_paths=input_files,
+          input_strings=input_strings)
+      self.failUnlessEqual(should_call, self.called, message)
+
+    CheckCallAndRecord(True, 'should call when record doesn\'t exist')
+    CheckCallAndRecord(False, 'should not call when nothing changed')
+
+    input_file1.write('some more input')
+    input_file1.flush()
+    CheckCallAndRecord(True, 'changed input file should trigger call')
+
+    input_files = input_files[::-1]
+    CheckCallAndRecord(False, 'reordering of inputs shouldn\'t trigger call')
+
+    input_files = input_files[:1]
+    CheckCallAndRecord(True, 'removing file should trigger call')
+
+    input_files.append(input_file2.name)
+    CheckCallAndRecord(True, 'added input file should trigger call')
+
+    input_strings[0] = input_strings[0] + ' a bit longer'
+    CheckCallAndRecord(True, 'changed input string should trigger call')
+
+    input_strings = input_strings[::-1]
+    CheckCallAndRecord(True, 'reordering of string inputs should trigger call')
+
+    input_strings = input_strings[:1]
+    CheckCallAndRecord(True, 'removing a string should trigger call')
+
+    input_strings.append('a brand new string')
+    CheckCallAndRecord(True, 'added input string should trigger call')
+
+
+if __name__ == '__main__':
+  unittest.main()