Fix Renderer generator script.

This script breaks peridocially because we don't have automated tests
for it. Split the FBO attachment object class into its own file, and
also fix a couple other small snags that prevented the script from
running.

This will facilitate generating Vulkan renderer stubs.

BUG=angleproject:1319

Change-Id: I30a6ce4ab0adad962cea76731dbe82837c5c9a1b
Reviewed-on: https://chromium-review.googlesource.com/347064
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
diff --git a/scripts/generate_new_renderer.py b/scripts/generate_new_renderer.py
new file mode 100644
index 0000000..2ad89ed
--- /dev/null
+++ b/scripts/generate_new_renderer.py
@@ -0,0 +1,280 @@
+#!/usr/bin/python
+#
+# Copyright (c) 2015 The ANGLE Project Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+#
+# generate_new_renderer.py:
+#   Utility script to generate stubs for a new Renderer class.
+#   Usage: generate_new_renderer.py <renderer name> <renderer suffix>
+#     Renderer name is the folder for the renderer subdirectory
+#     Renderer suffix is the abbreviation to append after the class names.
+#
+# The script is fairly robust but may not work for all new methods or
+# other unexpected features. It expects that abstract methods are all
+# grouped after the public destructor or after the private
+# DISALLOW_COPY_AND_ASSIGN macro.
+
+import os, sys, re, string, datetime
+
+if len(sys.argv) < 3:
+    print('Usage: ' + sys.argv[0] + ' <renderer dir name> <renderer class suffix>')
+    sys.exit(1)
+
+renderer_name = sys.argv[1]
+renderer_suffix = sys.argv[2]
+
+# change to the renderer directory
+os.chdir(os.path.join(os.path.dirname(sys.argv[0]), "..", "src", "libANGLE", "renderer"))
+
+# ensure subdir exists
+if not os.path.isdir(renderer_name):
+    os.mkdir(renderer_name)
+
+impl_classes = [
+    'Buffer',
+    'Compiler',
+    'Context',
+    'Device',
+    'Display',
+    'FenceNV',
+    'FenceSync',
+    'Framebuffer',
+    'Image',
+    'Program',
+    'Query',
+    'Renderbuffer',
+    'Sampler',
+    'Shader',
+    'Surface',
+    'Texture',
+    'TransformFeedback',
+    'VertexArray',
+]
+
+h_file_template = """//
+// Copyright 2016 The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// $TypedImpl.h:
+//    Defines the class interface for $TypedImpl, implementing $BaseImpl.
+//
+
+#ifndef LIBANGLE_RENDERER_${RendererNameCaps}_${TypedImplCaps}_H_
+#define LIBANGLE_RENDERER_${RendererNameCaps}_${TypedImplCaps}_H_
+
+#include "libANGLE/renderer/$BaseImpl.h"
+
+namespace rx
+{
+
+class $TypedImpl : public $BaseImpl
+{
+  public:
+    $TypedImpl($ConstructorParams);
+    ~$TypedImpl() override;
+$ImplMethodDeclarations$PrivateImplMethodDeclarations};
+
+}  // namespace rx
+
+#endif  // LIBANGLE_RENDERER_${RendererNameCaps}_${TypedImplCaps}_H_
+"""
+
+cpp_file_template = """//
+// Copyright $Year The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// $TypedImpl.cpp:
+//    Implements the class methods for $TypedImpl.
+//
+
+#include "libANGLE/renderer/$RendererName/$TypedImpl.h"
+
+#include "common/debug.h"
+
+namespace rx
+{
+
+$TypedImpl::$TypedImpl($ConstructorParams) : $BaseImpl($BaseContructorArgs)
+{
+}
+
+$TypedImpl::~$TypedImpl()
+{
+}
+$ImplMethodDefinitions
+}  // namespace rx
+"""
+
+def generate_impl_declaration(impl_stub):
+    # ensure the wrapped lines are aligned vertically
+    temp = re.sub(r'\n        ', '\n', impl_stub)
+    return temp + ' override;\n'
+
+def generate_impl_definition(impl_stub, typed_impl):
+    function_signature = impl_stub.strip()
+
+    # strip comments
+    function_signature = re.sub(r'\/\/[^\n]*\n', '', function_signature).strip()
+
+    prog = re.compile(r'^(.+[ \*\&])([^ \(\*\&]+\()')
+    return_value = prog.match(function_signature).group(1)
+
+    # ensure the wrapped lines are aligned vertically
+    spaces = ' ' * len(typed_impl)
+    function_signature = re.sub(r'\n          ', '\n' + spaces, function_signature)
+
+    # add class scoping
+    function_signature = prog.sub(r'\1' + typed_impl + r'::\2', function_signature)
+    function_signature += '\n'
+
+    return_statement = ''
+    return_type = return_value.strip()
+
+    if return_type != 'void':
+        # specialized return values for Errors, pointers, etc
+        if return_type == 'gl::Error':
+            return_statement = '    return gl::Error(GL_INVALID_OPERATION);\n'
+        elif return_type == 'egl::Error':
+            return_statement = '    return egl::Error(EGL_BAD_ACCESS);\n'
+        elif return_type == 'LinkResult':
+            return_statement = '    return LinkResult(false, gl::Error(GL_INVALID_OPERATION));\n'
+        elif re.search(r'\*$', return_type):
+            return_statement = '    return static_cast<' + return_type + '>(0);\n'
+        elif re.search(r'const ([^ \&]+) \&$', return_type):
+            obj_type = re.search(r'const ([^ \&]+) \&$', return_type).group(1)
+            return_statement = '    static ' + obj_type + ' local;\n' + '    return local;\n'
+        else:
+            return_statement = '    return ' + return_type + '();\n'
+
+    body = '{\n' + '    UNIMPLEMENTED();\n' + return_statement +'}\n'
+
+    return '\n' + function_signature + body
+
+def get_constructor_args(constructor):
+    params = re.search(r'\((.*)\)', constructor).group(1)
+    args = ', '.join(re.findall(r'[^\w]?(\w+)(?:\,|$)', params))
+    return params, args
+
+def parse_impl_header(base_impl):
+    impl_h_file_path = base_impl + '.h'
+    impl_h_file = open(impl_h_file_path, 'r')
+
+    # extract impl stubs
+    copy = False
+    copy_private = False
+    impl_stubs = ''
+    private_impl_stubs = ''
+    constructor = base_impl + '() {}'
+    for line in impl_h_file:
+        clean_line = line.strip()
+
+        match = re.search(r'^(?:explicit )?(' + base_impl + r'\([^\)]*\))', clean_line);
+        if match:
+            constructor = match.group(1)
+
+        # begin capture when reading the destructor.
+        # begin capture also in the private scope (a few special cases)
+        # end capture when we reach a non-virtual function, or different scope.
+        if '~' + base_impl in clean_line:
+            copy = True
+            copy_private = False
+        elif 'private:' in clean_line:
+            copy = False
+            copy_private = True
+        elif ';' in clean_line and ' = 0' not in clean_line:
+            copy = False
+            copy_private = False
+        elif '}' in clean_line or 'protected:' in clean_line or 'private:' in clean_line:
+            copy = False
+            copy_private = False
+        elif copy:
+            impl_stubs += line
+        elif copy_private:
+            private_impl_stubs += line
+
+    impl_h_file.close()
+
+    return impl_stubs, private_impl_stubs, constructor
+
+def get_base_class(base_impl):
+    impl_h_file_path = base_impl + '.h'
+    with open(impl_h_file_path, 'r') as impl_h_file:
+        for line in impl_h_file:
+            match = re.search(r'^class ' + base_impl + r' : public (\w+)', line)
+            if match:
+                return match.group(1)
+    return False
+
+for impl_class in impl_classes:
+
+    base_impl = impl_class + 'Impl'
+    typed_impl = impl_class + renderer_suffix
+
+    h_file_path = os.path.join(renderer_name, typed_impl + '.h')
+    cpp_file_path = os.path.join(renderer_name, typed_impl + '.cpp')
+
+    h_file = open(h_file_path, 'w')
+    cpp_file = open(cpp_file_path, 'w')
+
+    # extract impl stubs
+    impl_stubs, private_impl_stubs, constructor = parse_impl_header(base_impl)
+
+    # Handle base classes, skipping angle::NonCopyable.
+    base_class = get_base_class(base_impl)
+    if base_class and base_class != 'angle':
+        base_impl_stubs, base_private_impl_stubs, base_constructor = parse_impl_header(base_class)
+        impl_stubs += base_impl_stubs
+        private_impl_stubs += base_private_impl_stubs
+
+    impl_method_declarations = ''
+    impl_method_definitions = ''
+    private_impl_method_declarations = ''
+
+    for impl_stub in impl_stubs.split(' = 0;\n'):
+        # use 'virtual' to identify the strings with functions
+        if 'virtual' in impl_stub:
+            temp = re.sub(r'virtual ', '', impl_stub)
+            impl_method_declarations += generate_impl_declaration(temp)
+            impl_method_definitions += generate_impl_definition(temp, typed_impl)
+
+    for impl_stub in private_impl_stubs.split(' = 0;\n'):
+        # use 'virtual' to identify the strings with functions
+        if 'virtual' in impl_stub:
+            temp = re.sub(r'virtual ', '', impl_stub)
+            private_impl_method_declarations += generate_impl_declaration(temp)
+            impl_method_definitions += generate_impl_definition(temp, typed_impl)
+
+    constructor_params, base_constructor_args = get_constructor_args(constructor)
+
+    if private_impl_method_declarations:
+        private_impl_method_declarations = "\n  private:\n" + private_impl_method_declarations
+
+    substitutions = {
+        'BaseImpl': base_impl,
+        'TypedImpl': typed_impl,
+        'TypedImplCaps': typed_impl.upper(),
+        'RendererName': renderer_name,
+        'RendererNameCaps': renderer_name.upper(),
+        'ImplMethodDeclarations': impl_method_declarations,
+        'ImplMethodDefinitions': impl_method_definitions,
+        'ConstructorParams': constructor_params,
+        'BaseContructorArgs': base_constructor_args,
+        'PrivateImplMethodDeclarations': private_impl_method_declarations,
+        'Year': datetime.datetime.now().year,
+    }
+
+    h_file.write(string.Template(h_file_template).substitute(substitutions))
+    cpp_file.write(string.Template(cpp_file_template).substitute(substitutions))
+
+    h_file.close()
+    cpp_file.close()
+
+# Print a block of source files to add to the GYP
+print("Generated files:")
+for impl_class in impl_classes:
+    path = "libANGLE/renderer/" + renderer_name + "/" + impl_class + renderer_suffix
+    print('\'' + path + ".cpp\',")
+    print('\'' + path + ".h\',")