jinja2: support file references in templates.

build/android/gyp/jinja_template.py

Index: build/android/gyp/jinja_template.py
diff --git a/build/android/gyp/jinja_template.py b/build/android/gyp/jinja_template.py
index 3a93f746fe14891caef4d3aaf6a3377ab2b4fc9e..9c764c3126ae72bbaacb8f5f0ef89c1c191075bf 100755
--- a/build/android/gyp/jinja_template.py
+++ b/build/android/gyp/jinja_template.py
@@ -18,18 +18,31 @@ sys.path.append(os.path.join(os.path.dirname(__file__), '../../../third_party'))
 import jinja2  # pylint: disable=F0401
 
 
-def ProcessFile(input_filename, output_filename, variables):
-  with codecs.open(input_filename, 'r', 'utf-8') as input_file:
-    input_ = input_file.read()
-  env = jinja2.Environment(undefined=jinja2.StrictUndefined)
-  template = env.from_string(input_)
-  template.filename = os.path.abspath(input_filename)
+class RecordingFileSystemLoader(jinja2.FileSystemLoader):
+  '''A FileSystemLoader that stores a list of loaded templates.'''
+  def __init__(self, searchpath):
+    jinja2.FileSystemLoader.__init__(self, searchpath)
+    self.loaded_templates = []

[cjhopman, 2015/03/17 18:03:33]

Should this be a set? Idk if ninja cares about duplicate entries in depfiles (it
probably doesn't).

[newt (away), 2015/03/17 18:58:28]

Changed to set.

+
+  def get_source(self, environment, template):
+    contents, filename, uptodate = jinja2.FileSystemLoader.get_source(

[cjhopman, 2015/03/17 18:03:33]

is filename relative or absolute? We should make sure that it is relative to the
current directory.

[newt (away), 2015/03/17 18:44:47]

They're absolute paths currently. Curious: why do they need to be relative?

[newt (away), 2015/03/17 18:58:28]

Changed to relative.

[cjhopman, 2015/03/17 19:01:53]

I believe that ninja will treat a relative path and an absolute path to the same
file as different files. Then, if you have an output of one thing as the input
of another, and one specifies it as relative, the other as absolute, you will
have a bad time. And so, we make everything relative.

thakis@ really doesn't like absolute paths, but I think he usually says it's
because he tends to rename output directories and wants things to still work. I
don't know how common that is among other people and I care much more about the
first point.

+        self, environment, template)
+    self.loaded_templates.append(filename)
+    return contents, filename, uptodate
+
+  def get_loaded_templates(self):
+    return self.loaded_templates
+
+
+def ProcessFile(env, input_filename, output_filename, variables):
+  input_rel_path = os.path.relpath(input_filename, build_utils.CHROMIUM_SRC)
+  template = env.get_template(input_rel_path)
   output = template.render(variables)
   with codecs.open(output_filename, 'w', 'utf-8') as output_file:
     output_file.write(output)
 
 
-def ProcessFiles(input_filenames, inputs_base_dir, outputs_zip, variables):
+def ProcessFiles(env, input_filenames, inputs_base_dir, outputs_zip, variables):
   with build_utils.TempDir() as temp_dir:
     for input_filename in input_filenames:
       relpath = os.path.relpath(os.path.abspath(input_filename),
@@ -41,7 +54,7 @@ def ProcessFiles(input_filenames, inputs_base_dir, outputs_zip, variables):
       output_filename = os.path.join(temp_dir, relpath)
       parent_dir = os.path.dirname(output_filename)
       build_utils.MakeDirectory(parent_dir)
-      ProcessFile(input_filename, output_filename, variables)
+      ProcessFile(env, input_filename, output_filename, variables)
 
     build_utils.ZipDir(outputs_zip, temp_dir)
 
@@ -82,14 +95,17 @@ def main():
     name, _, value = v.partition('=')
     variables[name] = value
 
+  loader = RecordingFileSystemLoader(build_utils.CHROMIUM_SRC)
+  env = jinja2.Environment(loader=loader, undefined=jinja2.StrictUndefined,
+                           line_comment_prefix='##')
   if options.output:
-    ProcessFile(inputs[0], options.output, variables)
+    ProcessFile(env, inputs[0], options.output, variables)
   else:
-    ProcessFiles(inputs, options.inputs_base_dir, options.outputs_zip,
+    ProcessFiles(env, inputs, options.inputs_base_dir, options.outputs_zip,
                  variables)
 
   if options.depfile:
-    deps = inputs + build_utils.GetPythonDependencies()
+    deps = loader.get_loaded_templates() + build_utils.GetPythonDependencies()
     build_utils.WriteDepfile(options.depfile, deps)