1 files changed, 87 insertions, 0 deletions
diff --git a/mesonbuild/scripts/depscan.py b/mesonbuild/scripts/depscan.py
new file mode 100644
index 0000000..161faf8
--- /dev/null
+++ b/mesonbuild/scripts/depscan.py
@@ -0,0 +1,87 @@
+# Copyright 2020 The Meson development team
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import pathlib
+import pickle
+import re
+import typing as T
+
+import_re = re.compile('\w*import ([a-zA-Z0-9]+);')
+export_re = re.compile('\w*export module ([a-zA-Z0-9]+);')
+
+class DependencyScanner:
+    def __init__(self, pickle_file, outfile, sources):
+        with open(pickle_file, 'rb') as pf:
+            self.target_data = pickle.load(pf)
+        self.outfile = outfile
+        self.sources = sources
+        self.provided_by = {}
+        self.exports = {}
+        self.needs = {}
+        self.sources_with_exports = []
+    
+    def scan_file(self, fname):
+        for line in pathlib.Path(fname).read_text().split('\n'):
+            import_match = import_re.match(line)
+            export_match = export_re.match(line)
+            if import_match:
+                needed = import_match.group(1)
+                if fname in self.needs:
+                    self.needs[fname].append(needed)
+                else:
+                    self.needs[fname] = [needed]
+            if export_match:
+                exported_module = export_match.group(1)
+                if exported_module in self.provided_by:
+                    raise RuntimeError('Multiple files provide module {}.'.format(exported_module))
+                self.sources_with_exports.append(fname)
+                self.provided_by[exported_module] = fname
+                self.exports[fname] = exported_module
+
+    def objname_for(self, src):
+        return self.target_data.source2object[src]
+
+    def ifcname_for(self, src):
+        return '{}.ifc'.format(self.exports[src])
+
+    def scan(self):
+        for s in self.sources:
+            self.scan_file(s)
+        with open(self.outfile, 'w') as ofile:
+            ofile.write('ninja_dyndep_version = 1\n')
+            for src in self.sources:
+                objfilename = self.objname_for(src)
+                if src in self.sources_with_exports:
+                    ifc_entry = '| ' + self.ifcname_for(src)
+                else:
+                    ifc_entry = ''
+                if src in self.needs:
+                    # FIXME, handle all sources, not just the first one
+                    modname = self.needs[src][0]
+                    provider_src = self.provided_by[modname]
+                    provider_ifc = self.ifcname_for(provider_src)
+                    mod_dep = '| ' + provider_ifc
+                else:
+                    mod_dep = ''
+                ofile.write('build {} {}: dyndep {}\n'.format(objfilename,
+                                                              ifc_entry,
+                                                              mod_dep))
+        return 0
+
+def run(args: T.List[str]) -> int:
+    pickle_file = args[0]
+    outfile = args[1]
+    sources = args[2:]
+    scanner = DependencyScanner(pickle_file, outfile, sources)
+    return scanner.scan()