Split Jinja-related CodeGeneratorV8 guts into a separate class.

* Introduces CodeGeneratorBase, which contains most of the
  Jinja-related plumbing.
* Shifts some common functions along with it into a new file.

R=yukishiino,bashi
BUG=603795
TEST=Tools/Scripts/run-bindings-tests

Review-Url: https://codereview.chromium.org/2345083004
Cr-Commit-Position: refs/heads/master@{#419643}

third_party/WebKit/Source/bindings/scripts/BUILD.gn

@@ -30,9 +30,9 @@ action("cached_lex_yacc_tables") {
 # Jinja (which improves speed significantly), as the bytecode cache is
 # not concurrency-safe on write; details in code_generator_v8.py.
 action("cached_jinja_templates") {
-  script = "code_generator_v8.py"
+  script = "code_generator.py"
 
-  inputs = jinja_module_files + [ "code_generator_v8.py" ] +
+  inputs = jinja_module_files + [ "code_generator.py" ] +
            code_generator_template_files
 
   # Dummy file to track dependency.

third_party/WebKit/Source/bindings/scripts/code_generator.py

+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# pylint: disable=import-error,print-statement,relative-import
+
+"""Plumbing for a Jinja-based code generator, including CodeGeneratorBase, a base class for all generators."""
+
+import os
+import posixpath
+import re
+import sys
+
+from idl_types import set_ancestors, IdlType
+from v8_attributes import attribute_filters
+from v8_globals import includes
+from v8_interface import constant_filters
+from v8_types import set_component_dirs
+from v8_methods import method_filters
+from v8_utilities import capitalize, for_origin_trial_feature, unique_by
+from utilities import (idl_filename_to_component, is_valid_component_dependency,
+                       format_remove_duplicates, format_blink_cpp_source_code)
+
+# Path handling for libraries and templates
+# Paths have to be normalized because Jinja uses the exact template path to
+# determine the hash used in the cache filename, and we need a pre-caching step
+# to be concurrency-safe. Use absolute path because __file__ is absolute if
+# module is imported, and relative if executed directly.
+# If paths differ between pre-caching and individual file compilation, the cache
+# is regenerated, which causes a race condition and breaks concurrent build,
+# since some compile processes will try to read the partially written cache.
+MODULE_PATH, _ = os.path.split(os.path.realpath(__file__))
+THIRD_PARTY_DIR = os.path.normpath(os.path.join(
+    MODULE_PATH, os.pardir, os.pardir, os.pardir, os.pardir))
+TEMPLATES_DIR = os.path.normpath(os.path.join(
+    MODULE_PATH, os.pardir, 'templates'))
+
+# jinja2 is in chromium's third_party directory.
+# Insert at 1 so at front to override system libraries, and
+# after path[0] == invoking script dir
+sys.path.insert(1, THIRD_PARTY_DIR)
+import jinja2
+
+
+def generate_indented_conditional(code, conditional):
+    # Indent if statement to level of original code
+    indent = re.match(' *', code).group(0)
+    return ('%sif (%s) {\n' % (indent, conditional) +
+            '    %s\n' % '\n    '.join(code.splitlines()) +
+            '%s}\n' % indent)
+
+
+# [Exposed]
+def exposed_if(code, exposed_test):
+    if not exposed_test:
+        return code
+    return generate_indented_conditional(code, 'executionContext && (%s)' % exposed_test)
+
+
+# [SecureContext]
+def secure_context_if(code, secure_context_test):
+    if not secure_context_test:
+        return code
+    return generate_indented_conditional(code, 'executionContext && (%s)' % secure_context_test)
+
+
+# [RuntimeEnabled]
+def runtime_enabled_if(code, runtime_enabled_function_name):
+    if not runtime_enabled_function_name:
+        return code
+    return generate_indented_conditional(code, '%s()' % runtime_enabled_function_name)
+
+
+def initialize_jinja_env(cache_dir):
+    jinja_env = jinja2.Environment(
+        loader=jinja2.FileSystemLoader(TEMPLATES_DIR),
+        # Bytecode cache is not concurrency-safe unless pre-cached:
+        # if pre-cached this is read-only, but writing creates a race condition.
+        bytecode_cache=jinja2.FileSystemBytecodeCache(cache_dir),
+        keep_trailing_newline=True,  # newline-terminate generated files
+        lstrip_blocks=True,  # so can indent control flow tags
+        trim_blocks=True)
+    jinja_env.filters.update({
+        'blink_capitalize': capitalize,
+        'exposed': exposed_if,
+        'for_origin_trial_feature': for_origin_trial_feature,
+        'format_blink_cpp_source_code': format_blink_cpp_source_code,
+        'format_remove_duplicates': format_remove_duplicates,
+        'runtime_enabled': runtime_enabled_if,
+        'secure_context': secure_context_if,
+        'unique_by': unique_by})
+    jinja_env.filters.update(attribute_filters())
+    jinja_env.filters.update(constant_filters())
+    jinja_env.filters.update(method_filters())
+    return jinja_env
+
+
+def normalize_and_sort_includes(include_paths):
+    normalized_include_paths = []
+    for include_path in include_paths:
+        match = re.search(r'/gen/blink/(.*)$', posixpath.abspath(include_path))
+        if match:
+            include_path = match.group(1)
+        normalized_include_paths.append(include_path)
+    return sorted(normalized_include_paths)
+
+
+class CodeGeneratorBase(object):
+    """Base class for jinja-powered jinja template generation.
+    """
+    def __init__(self, generator_name, info_provider, cache_dir, output_dir):
+        self.generator_name = generator_name
+        self.info_provider = info_provider
+        self.jinja_env = initialize_jinja_env(cache_dir)
+        self.output_dir = output_dir
+        self.set_global_type_info()
+
+    def should_generate_code(self, definitions):
+        return definitions.interfaces or definitions.dictionaries
+
+    def set_global_type_info(self):
+        interfaces_info = self.info_provider.interfaces_info
+        set_ancestors(interfaces_info['ancestors'])
+        IdlType.set_callback_interfaces(interfaces_info['callback_interfaces'])
+        IdlType.set_dictionaries(interfaces_info['dictionaries'])
+        IdlType.set_enums(self.info_provider.enumerations)
+        IdlType.set_implemented_as_interfaces(interfaces_info['implemented_as_interfaces'])
+        IdlType.set_garbage_collected_types(interfaces_info['garbage_collected_interfaces'])
+        set_component_dirs(interfaces_info['component_dirs'])
+
+    def render_template(self, include_paths, header_template, cpp_template,
+                        template_context, component=None):
+        template_context['code_generator'] = self.generator_name
+
+        # Add includes for any dependencies
+        template_context['header_includes'] = normalize_and_sort_includes(
+            template_context['header_includes'])
+
+        for include_path in include_paths:
+            if component:
+                dependency = idl_filename_to_component(include_path)
+                assert is_valid_component_dependency(component, dependency)
+            includes.add(include_path)
+
+        template_context['cpp_includes'] = normalize_and_sort_includes(includes)
+
+        header_text = header_template.render(template_context)
+        cpp_text = cpp_template.render(template_context)
+        return header_text, cpp_text
+
+    def generate_code(self, definitions, definition_name):
+        """Invokes code generation. The [definitions] argument is a list of definitions,
+        and the [definition_name] is the name of the definition
+        """
+        # This should be implemented in subclasses.
+        raise NotImplementedError()
+
+
+def main(argv):
+    # If file itself executed, cache templates
+    try:
+        cache_dir = argv[1]
+        dummy_filename = argv[2]
+    except IndexError:
+        print 'Usage: %s CACHE_DIR DUMMY_FILENAME' % argv[0]
+        return 1
+
+    # Cache templates
+    jinja_env = initialize_jinja_env(cache_dir)
+    template_filenames = [filename for filename in os.listdir(TEMPLATES_DIR)
+                          # Skip .svn, directories, etc.
+                          if filename.endswith(('.cpp', '.h'))]
+    for template_filename in template_filenames:
+        jinja_env.get_template(template_filename)
+
+    # Create a dummy file as output for the build system,
+    # since filenames of individual cache files are unpredictable and opaque
+    # (they are hashes of the template path, which varies based on environment)
+    with open(dummy_filename, 'w') as dummy_file:
+        pass  # |open| creates or touches the file
+
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv))

third_party/WebKit/Source/bindings/scripts/scripts.gni

@@ -39,6 +39,7 @@ idl_compiler_files = get_path_info([
                                      "interface_dependency_resolver.py",
 
                                      # V8 code generator
+                                     "code_generator.py",
                                      "code_generator_v8.py",
                                      "v8_attributes.py",
                                      "v8_callback_interface.py",