releasetools: Remove the global diff_done in blockimgdiff.py.

pylint complains about undefined `diff_done`:

W:754, 8: Global variable 'diff_done' undefined at the module level (global-variable-undefined)
W:820,14: Global variable 'diff_done' undefined at the module level (global-variable-undefined)

It would still warn about using global statement after adding the
definition.

W:859, 8: Using the global statement (global-statement)
W:925,14: Using the global statement (global-statement)

This CL computes 'diff_done' via 'len(diff_queue)' instead. It also
moves the progress reporting _before_ the diff work. This way it avoids
showing 100% progress with still changing filenames (because multiple
workers could see an empty queue simultaneously upon finishing their own
works).

There're possible alternatives, such as using the 'nonlocal' keyword in
Python 3 (which we're not there yet), or by using mutable object instead
(e.g. 'diff_done = [0]'). This CL looks cleaner, since it just kills the
var.

Test: Generate a BBOTA incremental. Check the on-screen progress
      report.
Test: `pylint --rcfile=pylintrc blockimgdiff.py` no longer complains
      about the global diff_done.
Change-Id: I339824735527e1f794b5b1dc99ff3fdb2da85744
1 file changed
tree: 165e2a3f49fe519f6df136a6dcabad7995537a3a
  1. core/
  2. target/
  3. tests/
  4. tools/
  5. .gitignore
  6. Android.mk
  7. buildspec.mk.default
  8. Changes.md
  9. CleanSpec.mk
  10. envsetup.sh
  11. help.sh
  12. navbar.md
  13. OWNERS
  14. README.md
  15. tapasHelp.sh
  16. Usage.txt
README.md

Android Make Build System

This is the Makefile-based portion of the Android Build System.

For documentation on how to run a build, see Usage.txt

For a list of behavioral changes useful for Android.mk writers see Changes.md

For an outdated reference on Android.mk files, see build-system.html. Our Android.mk files look similar, but are entirely different from the Android.mk files used by the NDK build system. When searching for documentation elsewhere, ensure that it is for the platform build system -- most are not.

This Makefile-based system is in the process of being replaced with Soong, a new build system written in Go. During the transition, all of these makefiles are read by Kati, and generate a ninja file instead of being executed directly. That's combined with a ninja file read by Soong so that the build graph of the two systems can be combined and run as one.