Add wire_cmd.py and dawn_wire.json to autogenerate all wire commands.

Unify code generation for Client->Server and Server->Client commands.
Methods in dawn.json are converted into command records and additional
commands are specified in dawn_wire.json. This can then be used to
completely generate the command handlers and command struct definitions.

Bug: dawn:88
Change-Id: Ic796796ede0aafe02e14f1f96790324dad92f4c0
Reviewed-on: https://dawn-review.googlesource.com/c/3800
Commit-Queue: Austin Eng <enga@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>

generator/wire_cmd.py

@@ -0,0 +1,93 @@
+# Copyright 2019 The Dawn Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from collections import namedtuple
+from common import Name
+import common
+
+def concat_names(*names):
+    return ' '.join([name.canonical_case() for name in names])
+
+# Create wire commands from api methods
+def compute_wire_params(api_params, wire_json):
+    wire_params = api_params.copy()
+    types = wire_params['types']
+
+    commands = []
+    return_commands = []
+
+    object_result_member = common.RecordMember(Name('result'), types['ObjectHandle'], 'value', False, True)
+
+    string_message_member = common.RecordMember(Name('message'), types['char'], 'const*', False, False)
+    string_message_member.length = 'strlen'
+
+    built_object_member = common.RecordMember(Name('built object'), types['ObjectHandle'], 'value', False, False)
+
+    callback_status_member = common.RecordMember(Name('status'), types['uint32_t'], 'value', False, False)
+
+    # Generate commands from object methods
+    for api_object in wire_params['by_category']['object']:
+        for method in api_object.methods:
+            if method.return_type.category != 'object' and method.return_type.name.canonical_case() != 'void':
+                # No other return types supported
+                continue
+
+            # Create object method commands by prepending "self"
+            members = [common.RecordMember(Name('self'), types[api_object.dict_name], 'value', False, False)]
+
+            members += method.arguments
+
+            # Client->Server commands that return an object return the result object handle
+            if method.return_type.category == 'object':
+                members.append(object_result_member)
+
+            command_name = concat_names(api_object.name, method.name)
+            command = common.Command(command_name, members)
+
+            command.derived_object = api_object
+            command.derived_method = method
+            commands.append(command)
+
+        # Create builder return ErrorCallback commands
+        # This can be removed when WebGPU error handling is implemented
+        if api_object.is_builder:
+            command_name = concat_names(api_object.name, Name('error callback'))
+
+            command = common.Command(command_name, [
+                built_object_member,
+                callback_status_member,
+                string_message_member,
+            ])
+            command.derived_object = api_object
+            return_commands.append(command)
+
+    for (name, json_data) in wire_json['commands'].items():
+        commands.append(common.Command(name, common.linked_record_members(json_data, types)))
+
+    for (name, json_data) in wire_json['return commands'].items():
+        return_commands.append(common.Command(name, common.linked_record_members(json_data, types)))
+
+    wire_params['cmd_records'] = {
+        'command': commands,
+        'return command': return_commands
+    }
+
+    for commands in wire_params['cmd_records'].values():
+        for command in commands:
+            command.update_metadata()
+        commands.sort(key=lambda c: c.name.canonical_case())
+
+    wire_params.update(wire_json.get('special items', {}))
+
+    return wire_params