CallAndRecordIfStale(): Add knownledge of output_files, depfiles, stamp

build/android/gyp/util/build_utils.py

Index: build/android/gyp/util/build_utils.py
diff --git a/build/android/gyp/util/build_utils.py b/build/android/gyp/util/build_utils.py
index 81041ef2f9bf6843e0e00dbbc779db05a34ff5c6..4e8f13378500567c0769cc143fb9f88792d1ac61 100644
--- a/build/android/gyp/util/build_utils.py
+++ b/build/android/gyp/util/build_utils.py
@@ -16,6 +16,7 @@ import sys
 import tempfile
 import zipfile
 
+from util import md5_check
 
 CHROMIUM_SRC = os.path.normpath(
     os.path.join(os.path.dirname(__file__),
@@ -400,3 +401,44 @@ def ExpandFileArgs(args):
 
   return new_args
 
+
+def CallAndRecordIfStale(function, options, record_path=None, input_paths=None,

[jbudorick, 2015/09/18 18:19:38]

curious: why'd you put this in here rather than in md5_check, and why would a
client call md5_check.CallAndRecordIfStale vs build_utils.CallAndRecordIfStale?

[agrieve, 2015/09/18 18:46:19]

My reasoning:
- md5_check felt a bit like a generic module, builddeps is very
our-build-system-specific. 
- The purpose of md5_check.CallAndRecordIfStale is to check md5s. & the purpose
of this wrapper is just to eliminate copy & paste surrounding our usage of it.

I'm open to slicing it another way, but that was my thinking. You'd use
md5_check.py directly if you don't want the builddeps logic.

[jbudorick, 2015/09/23 14:56:37]

I'm concerned about:
 - having two identically-named functions where one does A and the other does
A+B confusing people, myself included
 - having the former function only used by the latter, in which case they
probably don't need to be separate (or at least don't need to both be publicly
visible)

+                         input_strings=None, output_paths=None, force=False):
+  """Wraps md5_check.CallAndRecordIfStale() and also writes dep & stamp files.
+
+  Depfiles and stamp files are automatically added to output_paths when present
+  in the |options| arguemnt. They are then created after |function| is called.
+  """
+  if not output_paths:
+    raise Exception('At least one output_path must be specified.')
+  input_paths = list(input_paths or [])
+  input_strings = list(input_strings or [])
+  output_paths = list(output_paths or [])
+
+  python_deps = None
+  if hasattr(options, 'depfile') and options.depfile:

[jbudorick, 2015/09/18 18:19:38]

I'm not crazy about locking option names across scripts, tbh.

[agrieve, 2015/09/18 18:46:19]

All scripts already use build_utils.AddDepfileOption() to add this option, so
the name will be consistent.
As for .stamp, there's not a helper for it, but it's on the way out anyways (not
used in GN).

+    python_deps = GetPythonDependencies()
+    # List python deps in input_strings rather than input_paths since the
+    # contents of them does not change what gets written to the depfile.
+    input_strings += python_deps
+    output_paths += [options.depfile]
+
+  stamp_file = hasattr(options, 'stamp') and options.stamp
+  if stamp_file:
+    output_paths += [stamp_file]
+
+  def on_stale_md5():
+    function()
+    if python_deps is not None:
+      WriteDepfile(options.depfile, python_deps + input_paths)
+    if stamp_file:
+      Touch(stamp_file)
+
+  md5_check.CallAndRecordIfStale(
+      on_stale_md5,
+      record_path=record_path,
+      input_paths=input_paths,
+      input_strings=input_strings,
+      output_paths=output_paths,
+      force=force)
+