Bug 1407403 - Handle IPDL code generation in the tup backend; r=gps

IPDL generation consists of a single ipdl.py invocation on all the
*.ipdl and *.ipdlh files in the tree. Unfortunately the headers that are
generated are placed into directories corresponding to the namespaces
declared within the IDPL, and can't be determined solely based on the
input filename. As such, we have to do a quick parsing of the AST in
order to grab the namespaces and calculate the filenames for the .h
files.

The downside of this approach is that all *.ipdl/*.ipdlh files are
considered inputs for the tup backend, so editing one will perform
moz.build generation before running ipdl.py. This could be fixed by
either standardizing the generated header layout, or fixing tup to
somehow allow unspecified outputs.

MozReview-Commit-ID: DzF2ryLEsrg

--HG--
extra : rebase_source : 9297c7532b59e453dd2e985c7d2d5a1e78571893

python/mozbuild/mozbuild/backend/tup.py

@@ -5,6 +5,7 @@
 from __future__ import absolute_import, unicode_literals
 
 import os
+import sys
 
 import mozpack.path as mozpath
 from mozbuild.base import MozbuildObject
@@ -445,9 +446,53 @@ class TupOnly(CommonBackend, PartialBackend):
 
     def _handle_ipdl_sources(self, ipdl_dir, sorted_ipdl_sources,
                              unified_ipdl_cppsrcs_mapping):
-        # TODO: This isn't implemented yet in the tup backend, but it is called
-        # by the CommonBackend.
-        pass
+        # Preferably we wouldn't have to import ipdl, but we need to parse the
+        # ast in order to determine the namespaces since they are used in the
+        # header output paths.
+        sys.path.append(mozpath.join(self.environment.topsrcdir, 'ipc', 'ipdl'))
+        import ipdl
+
+        backend_file = self._get_backend_file('ipc/ipdl')
+        outheaderdir = '_ipdlheaders'
+        cmd = [
+            '$(PYTHON_PATH)',
+            '$(PLY_INCLUDE)',
+            '%s/ipdl.py' % backend_file.srcdir,
+            '--sync-msg-list=%s/sync-messages.ini' % backend_file.srcdir,
+            '--msg-metadata=%s/message-metadata.ini' % backend_file.srcdir,
+            '--outheaders-dir=%s' % outheaderdir,
+            '--outcpp-dir=.',
+        ]
+        ipdldirs = sorted(set(mozpath.dirname(p) for p in sorted_ipdl_sources))
+        cmd.extend(['-I%s' % d for d in ipdldirs])
+        cmd.extend(sorted_ipdl_sources)
+
+        outputs = ['IPCMessageTypeName.cpp', mozpath.join(outheaderdir, 'IPCMessageStart.h'), 'ipdl_lextab.py', 'ipdl_yacctab.py']
+
+        for filename in sorted_ipdl_sources:
+            filepath, ext = os.path.splitext(filename)
+            dirname, basename = os.path.split(filepath)
+            dirname = mozpath.relpath(dirname, self.environment.topsrcdir)
+
+            extensions = ['']
+            if ext == '.ipdl':
+                extensions.extend(['Child', 'Parent'])
+
+            with open(filename) as f:
+                ast = ipdl.parse(f.read(), filename, includedirs=ipdldirs)
+                self.backend_input_files.add(filename)
+            headerdir = os.path.join(outheaderdir, *([ns.name for ns in ast.namespaces]))
+
+            for extension in extensions:
+                outputs.append("%s%s.cpp" % (basename, extension))
+                outputs.append(mozpath.join(headerdir, '%s%s.h' % (basename, extension)))
+
+        backend_file.rule(
+            display='IPDL code generation',
+            cmd=cmd,
+            outputs=outputs,
+            check_unchanged=True,
+        )
 
     def _handle_webidl_build(self, bindings_dir, unified_source_mapping,
                              webidls, expected_build_output_files,