Bug 1122812 - part 1 - move unified file grouping to UnifiedSources's constructor; r=mshal

UnifiedSources, not the recursivemake backend, should be responsible for
figuring out what unified files to generate, and what those unified
files should contain.

python/mozbuild/mozbuild/backend/recursivemake.py

@@ -65,7 +65,6 @@ from ..frontend.data import (
 from ..util import (
     ensureParentDir,
     FileAvoidWrite,
-    group_unified_files,
 )
 from ..makeutil import Makefile
 
@@ -395,33 +394,17 @@ class RecursiveMakeBackend(CommonBackend):
             var = suffix_map[obj.canonical_suffix]
             non_unified_var = var[len('UNIFIED_'):]
 
-            files_per_unification = obj.files_per_unified_file
-            do_unify = files_per_unification > 1
-            # Sorted so output is consistent and we don't bump mtimes.
-            source_files = list(sorted(obj.files))
-
-            if do_unify:
-                # On Windows, path names have a maximum length of 255 characters,
-                # so avoid creating extremely long path names.
-                unified_prefix = mozpath.relpath(backend_file.objdir,
-                    backend_file.environment.topobjdir)
-                if len(unified_prefix) > 20:
-                    unified_prefix = unified_prefix[-20:].split('/', 1)[-1]
-                unified_prefix = unified_prefix.replace('/', '_')
-
-                suffix = obj.canonical_suffix[1:]
-                unified_prefix='Unified_%s_%s' % (suffix, unified_prefix)
-                unified_source_mapping = list(group_unified_files(source_files,
-                                                                  unified_prefix=unified_prefix,
-                                                                  unified_suffix=suffix,
-                                                                  files_per_unified_file=files_per_unification))
-                self._write_unified_files(unified_source_mapping, backend_file.objdir)
+            if obj.have_unified_mapping:
+                self._write_unified_files(obj.unified_source_mapping, backend_file.objdir)
                 self._add_unified_build_rules(backend_file,
-                    unified_source_mapping,
+                    obj.unified_source_mapping,
                     unified_files_makefile_variable=var,
                     include_curdir_build_rules=False)
                 backend_file.write('%s += $(%s)\n' % (non_unified_var, var))
             else:
+                # Sorted so output is consistent and we don't bump mtimes.
+                source_files = list(sorted(obj.files))
+
                 backend_file.write('%s += %s\n' % (
                     non_unified_var, ' '.join(source_files)))
         elif isinstance(obj, VariablePassthru):

python/mozbuild/mozbuild/frontend/data.py

@@ -27,6 +27,10 @@ from mozbuild.util import (
 import mozpack.path as mozpath
 from .context import FinalTargetValue
 
+from ..util import (
+    group_unified_files,
+)
+
 
 class TreeMetadata(object):
     """Base class for all data being captured."""
@@ -778,13 +782,32 @@ class UnifiedSources(BaseSources):
     """Represents files to be compiled in a unified fashion during the build."""
 
     __slots__ = (
-        'files_per_unified_file',
+        'have_unified_mapping',
+        'unified_source_mapping'
     )
 
     def __init__(self, context, files, canonical_suffix, files_per_unified_file=16):
         BaseSources.__init__(self, context, files, canonical_suffix)
 
-        self.files_per_unified_file = files_per_unified_file
+        self.have_unified_mapping = files_per_unified_file > 1
+
+        if self.have_unified_mapping:
+            # Sorted so output is consistent and we don't bump mtimes.
+            source_files = list(sorted(self.files))
+
+            # On Windows, path names have a maximum length of 255 characters,
+            # so avoid creating extremely long path names.
+            unified_prefix = context.relsrcdir
+            if len(unified_prefix) > 20:
+                unified_prefix = unified_prefix[-20:].split('/', 1)[-1]
+            unified_prefix = unified_prefix.replace('/', '_')
+
+            suffix = self.canonical_suffix[1:]
+            unified_prefix='Unified_%s_%s' % (suffix, unified_prefix)
+            self.unified_source_mapping = list(group_unified_files(source_files,
+                                                                   unified_prefix=unified_prefix,
+                                                                   unified_suffix=suffix,
+                                                                   files_per_unified_file=files_per_unified_file))
 
 
 class InstallationTarget(ContextDerived):

python/mozbuild/mozbuild/test/frontend/data/unified-sources-non-unified/moz.build

@@ -0,0 +1,21 @@
+# -*- Mode: python; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 40 -*-
+# Any copyright is dedicated to the Public Domain.
+# http://creativecommons.org/publicdomain/zero/1.0/
+
+UNIFIED_SOURCES += [
+    'bar.cxx',
+    'foo.cpp',
+    'quux.cc',
+]
+
+UNIFIED_SOURCES += [
+    'objc1.mm',
+    'objc2.mm',
+]
+
+UNIFIED_SOURCES += [
+    'c1.c',
+    'c2.c',
+]
+
+FILES_PER_UNIFIED_FILE = 1

python/mozbuild/mozbuild/test/frontend/test_emitter.py

@@ -725,7 +725,29 @@ class TestEmitterBasic(unittest.TestCase):
         for suffix, files in expected.items():
             sources = suffix_map[suffix]
             self.assertEqual(sources.files, files)
-            self.assertEqual(sources.files_per_unified_file, 32)
+            self.assertTrue(sources.have_unified_mapping)
+
+    def test_unified_sources_non_unified(self):
+        """Test that UNIFIED_SOURCES with FILES_PER_UNIFIED_FILE=1 works properly."""
+        reader = self.reader('unified-sources-non-unified')
+        objs = self.read_topsrcdir(reader)
+
+        self.assertEqual(len(objs), 3)
+        for o in objs:
+            self.assertIsInstance(o, UnifiedSources)
+
+        suffix_map = {obj.canonical_suffix: obj for obj in objs}
+        self.assertEqual(len(suffix_map), 3)
+
+        expected = {
+            '.cpp': ['bar.cxx', 'foo.cpp', 'quux.cc'],
+            '.mm': ['objc1.mm', 'objc2.mm'],
+            '.c': ['c1.c', 'c2.c'],
+        }
+        for suffix, files in expected.items():
+            sources = suffix_map[suffix]
+            self.assertEqual(sources.files, files)
+            self.assertFalse(sources.have_unified_mapping)
 
 if __name__ == '__main__':
     main()