Add option to GRIT to provide a resource ordering input file.

tools/grit/grit/format/rc_header.py

Index: tools/grit/grit/format/rc_header.py
diff --git a/tools/grit/grit/format/rc_header.py b/tools/grit/grit/format/rc_header.py
index 74e7127b5840b57a90aa022737c721f638280b33..69bd8a7717d4134bc6c9c7cb126c3abbecc219eb 100755
--- a/tools/grit/grit/format/rc_header.py
+++ b/tools/grit/grit/format/rc_header.py
@@ -77,6 +77,24 @@ def FormatDefines(root, output_all_resource_defines=True,
 
 
 _cached_ids = {}
+_predetermined_tids = {}

[Nico, 2017/02/17 21:44:08]

nit: python style guide says 2 blank lines between toplevels

[Alexei Svitkine (slow), 2017/02/17 22:07:51]

Done.

+
+def SetPredeterminedIdsFile(predetermined_ids_file):
+  global _predetermined_tids
+  if predetermined_ids_file:
+    _predetermined_tids = _ReadIdsFromFile(predetermined_ids_file)
+  else:
+    _predetermined_tids = {}
+
+
+def _ReadIdsFromFile(path):
+  with open(path, "r") as f:
+    content = f.readlines()
+  tids = {}  # Maps textual id to numeric id
+  for line in content:
+    tid, id = line.split()
+    tids[tid] = int(id)
+  return tids
 
 
 def GetIds(root):
@@ -85,15 +103,17 @@ def GetIds(root):
   Args:
     root: A GritNode.
   '''
+  global _cached_ids
+  global _predetermined_tids
   # TODO(benrg): Since other formatters use this, it might make sense to move it
   # and _ComputeIds to GritNode and store the cached ids as an attribute. On the
   # other hand, GritNode has too much random stuff already.
   if root not in _cached_ids:
-    _cached_ids[root] = _ComputeIds(root)
+    _cached_ids[root] = _ComputeIds(root, _predetermined_tids)
   return _cached_ids[root]
 
 
-def _ComputeIds(root):
+def _ComputeIds(root, predetermined_tids):
   from grit.node import empty, include, message, misc, structure
 
   ids = {}  # Maps numeric id to textual id
@@ -102,6 +122,11 @@ def _ComputeIds(root):
   group = None
   last_id = None
 
+  predetermined_ids = {}
+  if predetermined_ids:

[Nico, 2017/02/17 21:44:08]

given the previous lien, won't predetermined_ids always be false-y? (it's always
an empty dict now)

[Alexei Svitkine (slow), 2017/02/17 22:07:51]

Woops, this is meant to be predetermined_tids originally.

But actually even that wasn't needed - since predetermined_tids is also always
initialized to at least an empty dict. So the if wasn't needed - removed.

+    for tid, id in predetermined_tids.iteritems():
+      predetermined_ids[id] = tid
+
   for item in root:
     if isinstance(item, empty.GroupingNode):
       # Note: this won't work if any GroupingNode can be contained inside
@@ -129,9 +154,13 @@ def _ComputeIds(root):
       if tid in tids:
         continue
 
+      if predetermined_tids and tid in predetermined_tids:
+        id = predetermined_tids[tid]
+        reason = "from predetermined_tids map"
+
       # Some identifier nodes can provide their own id,
       # and we use that id in the generated header in that case.
-      if hasattr(item, 'GetId') and item.GetId():
+      elif hasattr(item, 'GetId') and item.GetId():
         id = long(item.GetId())
         reason = 'returned by GetId() method'
 
@@ -197,6 +226,10 @@ def _ComputeIds(root):
         print ('WARNING: Numeric resource IDs should be greater than 100 to\n'
                'avoid conflicts with system-defined resource IDs.')
 
+      if tid not in predetermined_tids and id in predetermined_ids:
+        raise exception.IdRangeOverlap('ID %d overlaps between %s and %s'
+                                       % (id, tid, predetermined_ids[tid]))
+
       ids[id] = tid
       tids[tid] = id
       id_reasons[id] = reason