Rearrange methods in updateicudata.py. [S]

After aosp/1557177 update-tzdata.py and updateicudata.py behaviour
slightly diverged. This CL allows to reuse that logic in
update-tzdata.py.

Bug: 204746181
Test: followed TZDB update instructions

Change-Id: If6b4d3917c1a3f2dfd9eb76f057c9a74494e3472
Merged-In: If6b4d3917c1a3f2dfd9eb76f057c9a74494e3472
Merged-In: Ie387579fdeea4707cd40627fa8cd83d135b75df5

2 files changed, 41 insertions, 23 deletions

diff --git a/tools/icuutil.py b/tools/icuutil.py
index 7c84b263f..f2b622d18 100644
--- a/tools/icuutil.py
+++ b/tools/icuutil.py
@@ -125,6 +125,9 @@ def MakeAndCopyIcuDataFiles(icu_build_dir):
   """Builds the ICU .dat and .jar files using the current src data.
 
   The files are copied back into the expected locations in the src tree.
+
+  This is a low-level method.
+  Please check :func:`GenerateIcuDataFiles()` for caveats.
   """
   # Keep track of the original cwd so we can go back to it at the end.
   original_working_dir = os.getcwd()
@@ -175,7 +178,9 @@ def MakeAndCopyOverlayTzIcuData(icu_build_dir, dest_file):
 
   The overlay file can be used as an overlay of a full ICU .dat file
   to provide newer time zone data. Some strings like translated
-  time zone names will be missing, but rules will be correct."""
+  time zone names will be missing, but rules will be correct.
+  """
+
   # Keep track of the original cwd so we can go back to it at the end.
   original_working_dir = os.getcwd()
 
@@ -246,9 +251,12 @@ def MakeAndCopyOverlayTzIcuData(icu_build_dir, dest_file):
   # Switch back to the original working cwd.
   os.chdir(original_working_dir)
 
-def RequiredToMakeLangInfo():
-  """ Returns true if icu4c/source/data/misc/langInfo.txt has been re-generated.
-  Returns false if re-generation is not needed.
+def _MakeLangInfo():
+  """ Regenerates icu4c/source/data/misc/langInfo.txt.
+  Returns true if the file was changed and false otherwise.
+
+  This is implementation detail, should not be called outside
+  of this script.
   """
 
   # Generate icu4c/source/data/misc/langInfo.txt by a ICU4J tool
@@ -277,6 +285,34 @@ def RequiredToMakeLangInfo():
   shutil.copyfile(langInfo_out_path, langInfo_dst_path)
   return True
 
+def GenerateIcuDataFiles():
+  """ There are ICU files generation of which depends on ICU itself.
+  This method repeatedly builds ICU and re-generates these files until they
+  converge, i.e. subsequent builds do not change these files.
+  """
+  _MakeIcuDataFilesOnce()
+
+  # If icu4c/source/data/misc/langInfo.txt is re-generated, the binary data files need to be
+  # re-generated. MakeIcuDataFiles() is called until it converges because the re-generation
+  # depends icu4j, and icu4j depends on the binary data files.
+  while _MakeLangInfo():
+    _MakeIcuDataFilesOnce()
+
+def _MakeIcuDataFilesOnce():
+  """Builds ICU and copies .dat and .jar files to expected places.
+  Build is invoked only once. It is unlikely that you need to call
+  this method outside of this script.
+
+  This is a low-level method.
+  Please check :func:`GenerateIcuDataFiles()` for caveats.
+  """
+  i18nutil.SwitchToNewTemporaryDirectory()
+  icu_build_dir = '%s/icu' % os.getcwd()
+
+  PrepareIcuBuild(icu_build_dir)
+
+  MakeAndCopyIcuDataFiles(icu_build_dir)
+
 def CopyLicenseFiles(target_dir):
   """Copies ICU license files to the target_dir"""
 
diff --git a/tools/updateicudata.py b/tools/updateicudata.py
index 175761920..e814f4d21 100755
--- a/tools/updateicudata.py
+++ b/tools/updateicudata.py
@@ -4,10 +4,8 @@
 
 from __future__ import print_function
 
-import os
 import sys
 
-import i18nutil
 import icuutil
 
 
@@ -16,26 +14,10 @@ def main():
   icu_dir = icuutil.icuDir()
   print('Found icu in %s ...' % icu_dir)
 
-  makeIcuDataFiles()
-
-  # if icu4c/source/data/misc/langInfo.txt is re-generated, the binary data files need to be
-  # re-generated. makeIcuDataFiles() are called until it coverages because the re-generation
-  # depends icu4j, and icu4j depends on the bigit nary data files.
-  while (icuutil.RequiredToMakeLangInfo()):
-    makeIcuDataFiles()
-
+  icuutil.GenerateIcuDataFiles()
 
   print('Look in %s for new data files' % icu_dir)
   sys.exit(0)
 
-def makeIcuDataFiles():
-  i18nutil.SwitchToNewTemporaryDirectory()
-  icu_build_dir = '%s/icu' % os.getcwd()
-
-  icuutil.PrepareIcuBuild(icu_build_dir)
-
-  icuutil.MakeAndCopyIcuDataFiles(icu_build_dir)
-
-
 if __name__ == '__main__':
   main()