Use hermetic timestamps in apkbuilder.py and refactor helper function

This makes it so that the command will always produce the same output
given the same inputs.

BUG=

Review URL: https://codereview.chromium.org/1452843002

Cr-Commit-Position: refs/heads/master@{#361198}

4 files changed, 67 insertions, 43 deletions

diff --git a/build/android/gyp/apkbuilder.py b/build/android/gyp/apkbuilder.py
index 7e0ce23..1837fd6 100755
--- a/build/android/gyp/apkbuilder.py
+++ b/build/android/gyp/apkbuilder.py
@@ -92,16 +92,13 @@ def _AddAssets(apk, paths, disable_compression=False):
   """
   # Group all uncompressed assets together in the hope that it will increase
   # locality of mmap'ed files.
-  for target_compress_type in (zipfile.ZIP_STORED, zipfile.ZIP_DEFLATED):
+  for target_compress in (False, True):
     for path in paths:
       src_path, dest_path = _SplitAssetPath(path)
 
-      compress_type = zipfile.ZIP_DEFLATED
-      if disable_compression or (
-          os.path.splitext(src_path)[1] in _NO_COMPRESS_EXTENSIONS):
-        compress_type = zipfile.ZIP_STORED
-
-      if target_compress_type == compress_type:
+      compress = not disable_compression and (
+          os.path.splitext(src_path)[1] not in _NO_COMPRESS_EXTENSIONS)
+      if target_compress == compress:
         apk_path = 'assets/' + dest_path
         try:
           apk.getinfo(apk_path)
@@ -109,7 +106,8 @@ def _AddAssets(apk, paths, disable_compression=False):
           raise Exception('Multiple targets specified the asset path: %s' %
                           apk_path)
         except KeyError:
-          apk.write(src_path, apk_path, compress_type)
+          build_utils.AddToZipHermetic(apk, apk_path, src_path=src_path,
+                                       compress=compress)
 
 
 def main(args):
@@ -148,36 +146,39 @@ def main(args):
         _AddAssets(apk, options.uncompressed_assets, disable_compression=True)
         for path in native_libs:
           basename = os.path.basename(path)
-          apk.write(path, 'lib/%s/%s' % (options.android_abi, basename))
+          apk_path = 'lib/%s/%s' % (options.android_abi, basename)
+          build_utils.AddToZipHermetic(apk, apk_path, src_path=path)
+
         for name in options.native_lib_placeholders:
           # Make it non-empty so that its checksum is non-zero and is not
           # ignored by md5_check.
-          apk.writestr('lib/%s/%s' % (options.android_abi, name), ':)',
-                       zipfile.ZIP_STORED)
-        if options.dex_file:
-          if options.dex_file.endswith('.zip'):
-            with zipfile.ZipFile(options.dex_file, 'r') as dex_zip:
-              for dex in (d for d in dex_zip.namelist() if d.endswith('.dex')):
-                apk.writestr(dex, dex_zip.read(dex))
-          else:
-            apk.write(options.dex_file, 'classes.dex')
+          apk_path = 'lib/%s/%s.so' % (options.android_abi, name)
+          build_utils.AddToZipHermetic(apk, apk_path, data=':)')
+
+        if options.dex_file and options.dex_file.endswith('.zip'):
+          with zipfile.ZipFile(options.dex_file, 'r') as dex_zip:
+            for dex in (d for d in dex_zip.namelist() if d.endswith('.dex')):
+              build_utils.AddToZipHermetic(apk, dex, data=dex_zip.read(dex))
+        elif options.dex_file:
+          build_utils.AddToZipHermetic(apk, 'classes.dex',
+                                       src_path=options.dex_file)
 
         if options.emma_device_jar:
           # Add EMMA Java resources to APK.
           with zipfile.ZipFile(options.emma_device_jar, 'r') as emma_device_jar:
-            for emma_device_jar_entry in emma_device_jar.namelist():
-              entry_name_lower = emma_device_jar_entry.lower()
-              if entry_name_lower.startswith('meta-inf/'):
+            for apk_path in emma_device_jar.namelist():
+              apk_path_lower = apk_path.lower()
+              if apk_path_lower.startswith('meta-inf/'):
                 continue
 
-              if entry_name_lower.endswith('/'):
+              if apk_path_lower.endswith('/'):
                 continue
 
-              if entry_name_lower.endswith('.class'):
+              if apk_path_lower.endswith('.class'):
                 continue
 
-              apk.writestr(emma_device_jar_entry,
-                           emma_device_jar.read(emma_device_jar_entry))
+              build_utils.AddToZipHermetic(apk, apk_path,
+                                           data=emma_device_jar.read(apk_path))
 
       shutil.move(tmp_apk, options.output_apk)
     finally:
diff --git a/build/android/gyp/java_cpp_enum.py b/build/android/gyp/java_cpp_enum.py
index a82ebc2..9299bce 100755
--- a/build/android/gyp/java_cpp_enum.py
+++ b/build/android/gyp/java_cpp_enum.py
@@ -345,7 +345,7 @@ def DoMain(argv):
 
     with zipfile.ZipFile(options.srcjar, 'w', zipfile.ZIP_STORED) as srcjar:
       for output_path, data in DoGenerate(input_paths):
-        srcjar.writestr(build_utils.CreateHermeticZipInfo(output_path), data)
+        build_utils.AddToZipHermetic(srcjar, output_path, data=data)
   else:
     # TODO(agrieve): Delete this non-srcjar branch once GYP is gone.
     output_paths = []
diff --git a/build/android/gyp/java_google_api_keys.py b/build/android/gyp/java_google_api_keys.py
index 95257d3..62c92cd 100755
--- a/build/android/gyp/java_google_api_keys.py
+++ b/build/android/gyp/java_google_api_keys.py
@@ -12,6 +12,8 @@ import string
 import sys
 import zipfile
 
+from util import build_utils
+
 sys.path.append(
     os.path.abspath(os.path.join(sys.path[0], '../../../google_apis')))
 import google_api_keys
@@ -23,8 +25,6 @@ from pylib import constants
 
 PACKAGE = 'org.chromium.chrome'
 CLASSNAME = 'GoogleAPIKeys'
-HERMETIC_TIMESTAMP = (2001, 1, 1, 0, 0, 0)
-HERMETIC_FILE_ATTR = (0644 << 16L)
 
 
 def GetScriptName():
@@ -84,10 +84,8 @@ def _DoWriteJarOutput(output_path, constant_definition):
     os.makedirs(folder)
   with zipfile.ZipFile(output_path, 'w') as srcjar:
     path = '%s/%s' % (PACKAGE.replace('.', '/'), CLASSNAME + '.java')
-    zipinfo = zipfile.ZipInfo(filename=path,
-                              date_time=HERMETIC_TIMESTAMP)
-    zipinfo.external_attr = HERMETIC_FILE_ATTR
-    srcjar.writestr(zipinfo, GenerateOutput(constant_definition))
+    data = GenerateOutput(constant_definition)
+    build_utils.AddToZipHermetic(srcjar, path, data=data)
 
 
 def _DoMain(argv):
diff --git a/build/android/gyp/util/build_utils.py b/build/android/gyp/util/build_utils.py
index 94935d2..a8eb7c4 100644
--- a/build/android/gyp/util/build_utils.py
+++ b/build/android/gyp/util/build_utils.py
@@ -27,8 +27,8 @@ COLORAMA_ROOT = os.path.join(constants.DIR_SOURCE_ROOT,
 # aapt should ignore OWNERS files in addition the default ignore pattern.
 AAPT_IGNORE_PATTERN = ('!OWNERS:!.svn:!.git:!.ds_store:!*.scc:.*:<dir>_*:' +
                        '!CVS:!thumbs.db:!picasa.ini:!*~:!*.d.stamp')
-HERMETIC_TIMESTAMP = (2001, 1, 1, 0, 0, 0)
-HERMETIC_FILE_ATTR = (0644 << 16L)
+_HERMETIC_TIMESTAMP = (2001, 1, 1, 0, 0, 0)
+_HERMETIC_FILE_ATTR = (0644 << 16L)
 
 
 @contextlib.contextmanager
@@ -224,12 +224,39 @@ def ExtractAll(zip_path, path=None, no_clobber=True, pattern=None,
       z.extract(name, path)
 
 
-def CreateHermeticZipInfo(zip_path):
-  """Creates a ZipInfo with a zero'ed out timestamp."""
+def AddToZipHermetic(zip_file, zip_path, src_path=None, data=None,
+                     compress=None):
+  """Adds a file to the given ZipFile with a hard-coded modified time.
+
+  Args:
+    zip_file: ZipFile instance to add the file to.
+    zip_path: Destination path within the zip file.
+    src_path: Path of the source file. Mutually exclusive with |data|.
+    data: File data as a string.
+    compress: Whether to enable compression. Default is take from ZipFile
+        constructor.
+  """
+  assert (src_path is None) != (data is None), (
+      '|src_path| and |data| are mutually exclusive.')
   CheckZipPath(zip_path)
-  zipinfo = zipfile.ZipInfo(filename=zip_path, date_time=HERMETIC_TIMESTAMP)
-  zipinfo.external_attr = HERMETIC_FILE_ATTR
-  return zipinfo
+  zipinfo = zipfile.ZipInfo(filename=zip_path, date_time=_HERMETIC_TIMESTAMP)
+  zipinfo.external_attr = _HERMETIC_FILE_ATTR
+
+  if src_path:
+    with file(src_path) as f:
+      data = f.read()
+
+  # zipfile will deflate even when it makes the file bigger. To avoid
+  # growing files, disable compression at an arbitrary cut off point.
+  if len(data) < 16:
+    compress = False
+
+  # None converts to ZIP_STORED, when passed explicitly rather than the
+  # default passed to the ZipFile constructor.
+  args = []
+  if compress is not None:
+    args.append(zipfile.ZIP_DEFLATED if compress else zipfile.ZIP_STORED)
+  zip_file.writestr(zipinfo, data, *args)
 
 
 def DoZip(inputs, output, base_dir=None):
@@ -250,9 +277,7 @@ def DoZip(inputs, output, base_dir=None):
   input_tuples.sort(key=lambda tup: tup[0])
   with zipfile.ZipFile(output, 'w') as outfile:
     for zip_path, fs_path in input_tuples:
-      with file(fs_path) as f:
-        contents = f.read()
-      outfile.writestr(CreateHermeticZipInfo(zip_path), contents)
+      AddToZipHermetic(outfile, zip_path, src_path=fs_path)
 
 
 def ZipDir(output, base_dir):
@@ -283,7 +308,7 @@ def MergeZips(output, inputs, exclude_patterns=None, path_transform=None):
           dst_name = path_transform(name, in_file)
           already_added = dst_name in added_names
           if not already_added and not MatchesGlob(dst_name, exclude_patterns):
-            out_zip.writestr(CreateHermeticZipInfo(dst_name), in_zip.read(name))
+            AddToZipHermetic(out_zip, dst_name, data=in_zip.read(name))
             added_names.add(dst_name)