Add the ability to generate a depfile when running grit build.

grit/tool/build.py

Index: grit/tool/build.py
diff --git a/grit/tool/build.py b/grit/tool/build.py
index 596feb0a0f0d0ef7be4692375eb1fe62e9e6eb38..60fd3fa4a3e6da740026c62351fbbe0c5dd068d5 100644
--- a/grit/tool/build.py
+++ b/grit/tool/build.py
@@ -98,7 +98,8 @@ are exported to translation interchange files (e.g. XMB files), etc.
     first_ids_file = None
     whitelist_filenames = []
     target_platform = None
-    (own_opts, args) = getopt.getopt(args, 'o:D:E:f:w:t:')
+    deps_dir = None
+    (own_opts, args) = getopt.getopt(args, 'o:D:E:f:w:t:', ('deps-dir=',))
     for (key, val) in own_opts:
       if key == '-o':
         self.output_directory = val
@@ -117,6 +118,8 @@ are exported to translation interchange files (e.g. XMB files), etc.
         whitelist_filenames.append(val)
       elif key == '-t':
         target_platform = val
+      elif key == '--deps-dir':
+        deps_dir = val
 
     if len(args):
       print 'This tool takes no tool-specific arguments.'
@@ -147,6 +150,10 @@ are exported to translation interchange files (e.g. XMB files), etc.
     self.res.SetOutputLanguage('en')
     self.res.RunGatherers()
     self.Process()
+
+    if deps_dir:
+      self.GenerateDepsfile(opts.input, deps_dir)

[Jói, 2013/10/04 09:47:12]

I can't find the word "depsfile" in general usage on the web. Can we use "deps
file" instead? That would make this function name GenerateDepsFile and would
affect a few of the variable names below that are of the form depsfile_xyz.

[Nico, 2013/10/04 21:42:02]

It's called "depfile" in ninja:
http://martine.github.io/ninja/manual.html#_depfile That's probably a good name.
(i.e. drop the 's')

[koz (OOO until 15th September), 2013/10/09 06:01:16]

Renamed to depfile.

+
     return 0
 
   def __init__(self, defines=None):
@@ -251,9 +258,7 @@ are exported to translation interchange files (e.g. XMB files), etc.
       self.res.SetDefines(self.defines)
 
       # Make the output directory if it doesn't exist.
-      outdir = os.path.split(output.GetOutputFilename())[0]
-      if not os.path.exists(outdir):
-        os.makedirs(outdir)
+      self.MakeDirectoriesTo(output.GetOutputFilename())
 
       # Write the results to a temporary file and only overwrite the original
       # if the file changed.  This avoids unnecessary rebuilds.
@@ -304,3 +309,47 @@ are exported to translation interchange files (e.g. XMB files), etc.
     if self.res.UberClique().HasMissingTranslations():
       print self.res.UberClique().missing_translations_
       sys.exit(-1)
+
+  # Generate a depsfile that contains the imlicit dependencies of the input grd.

[Jói, 2013/10/04 09:47:12]

This should be a docstring, i.e. enclosed in """...""" and coming right after
the def GenerateDepsfile line.

[koz (OOO until 15th September), 2013/10/09 06:01:16]

Done.

+  # The deps file will be in the same format as a makefile, and will contain
+  # references to files relative to |deps_dir|. It will be put in the same
+  # directory as the generated outputs.
+  #
+  # For example, supposing we have three files in a directory src/
+  #
+  # src/
+  #   blah.grd    <- depends on input{1,2}.xtb
+  #   input1.xtb
+  #   input2.xtb
+  #
+  # and we run
+  #
+  #   grit -i blah.grd -g ../out/gen --deps-dir ../out
+  #
+  # from the directory src/ we will generate a depsfile ../out/gen/blah.grd.d
+  # that has the contents
+  #
+  #   gen/blah.grd.d: ../src/input1.xtb ../src/input2.xtb
+  #
+  # Note that all paths in the depsfile are relative to ../out, the deps-dir.
+  def GenerateDepsfile(self, input_filename, deps_dir):
+    depsfile_basename = os.path.basename(input_filename + '.d')
+    depsfile = os.path.abspath(
+        os.path.join(self.output_directory, depsfile_basename))
+    deps_dir = os.path.abspath(deps_dir)
+    # The path prefix to prepend to dependencies in the depsfile.
+    prefix = os.path.relpath(os.getcwd(), deps_dir)
+    # The path that the depsfile refers to itself by in the depsfile.
+    self_ref_depsfile = os.path.relpath(depsfile, deps_dir)
+    infiles = self.res.GetInputFiles()
+    deps_text = ' '.join([os.path.join(prefix, i) for i in infiles])
+    depsfile_contents = self_ref_depsfile + ': ' + deps_text
+    self.MakeDirectoriesTo(depsfile)
+    outfile = self.fo_create(depsfile, 'wb')
+    outfile.writelines(depsfile_contents)
+
+  # Creates directories necessary to contain |file|.

[Jói, 2013/10/04 09:47:12]

Move to docstring.

[koz (OOO until 15th September), 2013/10/09 06:01:16]

Done.

+  def MakeDirectoriesTo(self, file):

[Jói, 2013/10/04 09:47:12]

This can be an @staticmethod and skip the |self| parameter. There is at least
one example of this in the file.

[koz (OOO until 15th September), 2013/10/09 06:01:16]

Done.

+    dir = os.path.split(file)[0]
+    if not os.path.exists(dir):
+      os.makedirs(dir)