# Copyright (C) 2013 Google Inc. All rights reserved.
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# modification, are permitted provided that the following conditions are
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#     * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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"""Generate Blink V8 bindings (.h and .cpp files).

If run itself, caches Jinja templates (and creates dummy file for build,
since cache filenames are unpredictable and opaque).

This module is *not* concurrency-safe without care: bytecode caching creates
a race condition on cache *write* (crashes if one process tries to read a
partially-written cache). However, if you pre-cache the templates (by running
the module itself), then you can parallelize compiling individual files, since
cache *reading* is safe.

Input: An object of class IdlDefinitions, containing an IDL interface X
Output: V8X.h and V8X.cpp

Design doc: http://www.chromium.org/developers/design-documents/idl-compiler
"""

import os
import posixpath
import re
import sys

# 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, module_filename = 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, 'third_party'))
templates_dir = os.path.normpath(os.path.join(
    module_path, os.pardir, 'templates'))
# Make sure extension is .py, not .pyc or .pyo, so doesn't depend on caching
module_pyname = os.path.splitext(module_filename)[0] + '.py'

# 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

import idl_types
from idl_types import IdlType
import v8_callback_interface
import v8_dictionary
from v8_globals import includes, interfaces
import v8_interface
import v8_types
from v8_utilities import capitalize, cpp_name, conditional_string, v8_class_name


KNOWN_COMPONENTS = frozenset(['core', 'modules'])


def render_template(interface_info, header_template, cpp_template,
                    template_context):
    template_context['code_generator'] = module_pyname

    # Add includes for any dependencies
    template_context['header_includes'] = sorted(
        template_context['header_includes'])
    includes.update(interface_info.get('dependencies_include_paths', []))
    template_context['cpp_includes'] = sorted(includes)

    header_text = header_template.render(template_context)
    cpp_text = cpp_template.render(template_context)
    return header_text, cpp_text


class CodeGeneratorBase(object):
    """Base class for v8 bindings generator and IDL dictionary impl generator"""

    def __init__(self, interfaces_info, cache_dir, output_dir):
        interfaces_info = interfaces_info or {}
        self.interfaces_info = interfaces_info
        self.jinja_env = initialize_jinja_env(cache_dir)
        self.output_dir = output_dir

        # Set global type info
        idl_types.set_ancestors(dict(
            (interface_name, interface_info['ancestors'])
            for interface_name, interface_info in interfaces_info.iteritems()
            if interface_info['ancestors']))
        IdlType.set_callback_interfaces(set(
            interface_name
            for interface_name, interface_info in interfaces_info.iteritems()
            if interface_info['is_callback_interface']))
        IdlType.set_dictionaries(set(
            dictionary_name
            for dictionary_name, interface_info in interfaces_info.iteritems()
            if interface_info['is_dictionary']))
        IdlType.set_implemented_as_interfaces(dict(
            (interface_name, interface_info['implemented_as'])
            for interface_name, interface_info in interfaces_info.iteritems()
            if interface_info['implemented_as']))
        IdlType.set_garbage_collected_types(set(
            interface_name
            for interface_name, interface_info in interfaces_info.iteritems()
            if 'GarbageCollected' in interface_info['inherited_extended_attributes']))
        IdlType.set_will_be_garbage_collected_types(set(
            interface_name
            for interface_name, interface_info in interfaces_info.iteritems()
            if 'WillBeGarbageCollected' in interface_info['inherited_extended_attributes']))
        v8_types.set_component_dirs(dict(
            (interface_name, interface_info['component_dir'])
            for interface_name, interface_info in interfaces_info.iteritems()))

    def generate_code(self, definitions, definition_name):
        """Returns .h/.cpp code as ((path, content)...)."""
        # Set local type info
        IdlType.set_callback_functions(definitions.callback_functions.keys())
        IdlType.set_enums((enum.name, enum.values)
                          for enum in definitions.enumerations.values())
        return self.generate_code_internal(definitions, definition_name)

    def generate_code_internal(self, definitions, definition_name):
        # This should be implemented in subclasses.
        raise NotImplementedError()


class CodeGeneratorV8(CodeGeneratorBase):
    def __init__(self, interfaces_info, cache_dir, output_dir):
        CodeGeneratorBase.__init__(self, interfaces_info, cache_dir, output_dir)

    def output_paths(self, definition_name):
        header_path = posixpath.join(self.output_dir,
                                     'V8%s.h' % definition_name)
        cpp_path = posixpath.join(self.output_dir, 'V8%s.cpp' % definition_name)
        return header_path, cpp_path

    def generate_code_internal(self, definitions, definition_name):
        if definition_name in definitions.interfaces:
            return self.generate_interface_code(
                definitions, definition_name,
                definitions.interfaces[definition_name])
        if definition_name in definitions.dictionaries:
            return self.generate_dictionary_code(
                definitions, definition_name,
                definitions.dictionaries[definition_name])
        raise ValueError('%s is not in IDL definitions' % definition_name)

    def generate_interface_code(self, definitions, interface_name, interface):
        # Store other interfaces for introspection
        interfaces.update(definitions.interfaces)

        # Select appropriate Jinja template and contents function
        if interface.is_callback:
            header_template_filename = 'callback_interface.h'
            cpp_template_filename = 'callback_interface.cpp'
            interface_context = v8_callback_interface.callback_interface_context
        else:
            header_template_filename = 'interface.h'
            cpp_template_filename = 'interface.cpp'
            interface_context = v8_interface.interface_context
        header_template = self.jinja_env.get_template(header_template_filename)
        cpp_template = self.jinja_env.get_template(cpp_template_filename)

        interface_info = self.interfaces_info[interface_name]

        template_context = interface_context(interface)
        # Add the include for interface itself
        template_context['header_includes'].add(interface_info['include_path'])
        header_text, cpp_text = render_template(
            interface_info, header_template, cpp_template, template_context)
        header_path, cpp_path = self.output_paths(interface_name)
        return (
            (header_path, header_text),
            (cpp_path, cpp_text),
        )

    def generate_dictionary_code(self, definitions, dictionary_name,
                                 dictionary):
        header_template = self.jinja_env.get_template('dictionary_v8.h')
        cpp_template = self.jinja_env.get_template('dictionary_v8.cpp')
        template_context = v8_dictionary.dictionary_context(dictionary)
        interface_info = self.interfaces_info[dictionary_name]
        # Add the include for interface itself
        template_context['header_includes'].add(interface_info['include_path'])
        header_text, cpp_text = render_template(
            interface_info, header_template, cpp_template, template_context)
        header_path, cpp_path = self.output_paths(dictionary_name)
        return (
            (header_path, header_text),
            (cpp_path, cpp_text),
        )


class CodeGeneratorDictionaryImpl(CodeGeneratorBase):
    def __init__(self, interfaces_info, cache_dir, output_dir):
        CodeGeneratorBase.__init__(self, interfaces_info, cache_dir, output_dir)

    def output_paths(self, definition_name, interface_info):
        if interface_info['component_dir'] in KNOWN_COMPONENTS:
            output_dir = posixpath.join(self.output_dir,
                                        interface_info['relative_dir'])
        else:
            output_dir = self.output_dir
        header_path = posixpath.join(output_dir, '%s.h' % definition_name)
        cpp_path = posixpath.join(output_dir, '%s.cpp' % definition_name)
        return header_path, cpp_path

    def generate_code_internal(self, definitions, definition_name):
        if not definition_name in definitions.dictionaries:
            raise ValueError('%s is not an IDL dictionary')
        dictionary = definitions.dictionaries[definition_name]
        interface_info = self.interfaces_info[definition_name]
        header_template = self.jinja_env.get_template('dictionary_impl.h')
        cpp_template = self.jinja_env.get_template('dictionary_impl.cpp')
        template_context = v8_dictionary.dictionary_impl_context(
            dictionary, self.interfaces_info)
        header_text, cpp_text = render_template(
            interface_info, header_template, cpp_template, template_context)
        header_path, cpp_path = self.output_paths(
            definition_name, interface_info)
        return (
            (header_path, header_text),
            (cpp_path, cpp_text),
        )


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,
        'conditional': conditional_if_endif,
        'exposed': exposed_if,
        'runtime_enabled': runtime_enabled_if,
        })
    return jinja_env


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)


# [Conditional]
def conditional_if_endif(code, conditional_string):
    # Jinja2 filter to generate if/endif directive blocks
    if not conditional_string:
        return code
    return ('#if %s\n' % conditional_string +
            code +
            '#endif // %s\n' % conditional_string)


# [Exposed]
def exposed_if(code, exposed_test):
    if not exposed_test:
        return code
    return generate_indented_conditional(code, 'context && (%s)' % exposed_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 main(argv):
    # If file itself executed, cache templates
    try:
        cache_dir = argv[1]
        dummy_filename = argv[2]
    except IndexError as err:
        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))