generator/templates/dawn_wire/WireCmd.cpp - dawn - Git at Google

 //* Copyright 2017 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.

 #include "dawn_wire/WireCmd.h"

 #include "common/Assert.h"

 #include <cstring>

 //* Helper macros so that the main [de]serialization functions can be written in a generic manner.

 //* Outputs an rvalue that's the number of elements a pointer member points to.
 {% macro member_length(member, record_accessor) -%}
     {%- if member.length == "constant" -%}
         {{member.constant_length}}
     {%- else -%}
         {{record_accessor}}{{as_varName(member.length.name)}}
     {%- endif -%}
 {%- endmacro %}

 //* Outputs the type that will be used on the wire for the member
 {% macro member_transfer_type(member) -%}
     {%- if member.type.category == "object" -%}
         ObjectId
     {%- elif member.type.category == "structure" -%}
         {{as_cType(member.type.name)}}Transfer
     {%- else -%}
         {{as_cType(member.type.name)}}
     {%- endif -%}
 {%- endmacro %}

 //* Outputs the size of one element of the type that will be used on the wire for the member
 {% macro member_transfer_sizeof(member) -%}
     sizeof({{member_transfer_type(member)}})
 {%- endmacro %}

 //* Outputs the serialization code to put `in` in `out`
 {% macro serialize_member(member, in, out) %}
     {%- if member.type.category == "object" -%}
         {{out}} = provider.GetId({{in}});
     {% elif member.type.category == "structure"%}
         {{as_cType(member.type.name)}}Serialize({{in}}, &{{out}}, buffer, provider);
     {%- else -%}
         {{out}} = {{in}};
     {%- endif -%}
 {% endmacro %}

 //* Outputs the deserialization code to put `in` in `out`
 {% macro deserialize_member(member, in, out) %}
     {%- if member.type.category == "object" -%}
         DESERIALIZE_TRY(resolver.GetFromId({{in}}, &{{out}}));
     {% elif member.type.category == "structure"%}
         DESERIALIZE_TRY({{as_cType(member.type.name)}}Deserialize(&{{out}}, &{{in}}, buffer, size, allocator, resolver));
     {%- else -%}
         {{out}} = {{in}};
     {%- endif -%}
 {% endmacro %}

 //* The main [de]serialization macro

 //* Methods are very similar to structures that have one member corresponding to each arguments.
 //* This macro takes advantage of the similarity to output [de]serialization code for a record
 //* that is either a structure or a method, with some special cases for each.
 {% macro write_serialization_methods(name, members, as_method=None, as_struct=None, is_return_command=False) %}
     {% set Return = "Return" if is_return_command else "" %}
     {% set is_method = as_method != None %}
     {% set is_struct = as_struct != None %}

     //* Structure for the wire format of each of the records. Members that are values
     //* are embedded directly in the structure. Other members are assumed to be in the
     //* memory directly following the structure in the buffer.
     struct {{name}}Transfer {
         {% if is_method %}
             //* Start the transfer structure with the command ID, so that casting to WireCmd gives the ID.
             {{Return}}WireCmd commandId;

             //* Methods always have an implicit "self" argument.
             ObjectId self;

             //* Methods that return objects need to declare to the server which ID will be used for the
             //* return value.
             {% if as_method.return_type.category == "object" %}
                 ObjectId resultId;
                 ObjectSerial resultSerial;
             {% endif %}
         {% endif %}

         //* Value types are directly in the command, objects being replaced with their IDs.
         {% for member in members if member.annotation == "value" %}
             {{member_transfer_type(member)}} {{as_varName(member.name)}};
         {% endfor %}

         //* const char* have their length embedded directly in the command.
         {% for member in members if member.length == "strlen" %}
             size_t {{as_varName(member.name)}}Strlen;
         {% endfor %}
     };

     //* Returns the required transfer size for `record` in addition to the transfer structure.
     size_t {{name}}GetExtraRequiredSize(const {{name}}& record) {
         DAWN_UNUSED(record);

         size_t result = 0;

         //* Special handling of const char* that have their length embedded directly in the command
         {% for member in members if member.length == "strlen" %}
             result += std::strlen(record.{{as_varName(member.name)}});
         {% endfor %}

         //* Gather how much space will be needed for pointer members.
         {% for member in members if member.annotation != "value" and member.length != "strlen" %}
             {
                 size_t memberLength = {{member_length(member, "record.")}};
                 result += memberLength * {{member_transfer_sizeof(member)}};

                 //* Structures might contain more pointers so we need to add their extra size as well.
                 {% if member.type.category == "structure" %}
                     for (size_t i = 0; i < memberLength; ++i) {
                         result += {{as_cType(member.type.name)}}GetExtraRequiredSize(record.{{as_varName(member.name)}}[i]);
                     }
                 {% endif %}
             }
         {% endfor %}

         return result;
     }
     // GetExtraRequiredSize isn't used for structures that are value members of other structures
     // because we assume they cannot contain pointers themselves.
     DAWN_UNUSED_FUNC({{name}}GetExtraRequiredSize);

     //* Serializes `record` into `transfer`, using `buffer` to get more space for pointed-to data
     //* and `provider` to serialize objects.
     void {{name}}Serialize(const {{name}}& record, {{name}}Transfer* transfer,
                            char* buffer, const ObjectIdProvider& provider) {
         DAWN_UNUSED(provider);
         DAWN_UNUSED(buffer);

         //* Handle special transfer members of methods.
         {% if is_method %}
             {% if as_method.return_type.category == "object" %}
                 transfer->resultId = record.resultId;
                 transfer->resultSerial = record.resultSerial;
             {% endif %}

             transfer->commandId = {{Return}}WireCmd::{{name}};
             transfer->self = provider.GetId(record.self);
         {% endif %}

         //* Value types are directly in the transfer record, objects being replaced with their IDs.
         {% for member in members if member.annotation == "value" %}
             {% set memberName = as_varName(member.name) %}
             {{serialize_member(member, "record." + memberName, "transfer->" + memberName)}}
         {% endfor %}

         //* Special handling of const char* that have their length embedded directly in the command
         {% for member in members if member.length == "strlen" %}
             {% set memberName = as_varName(member.name) %}
             transfer->{{memberName}}Strlen = std::strlen(record.{{memberName}});

             memcpy(buffer, record.{{memberName}}, transfer->{{memberName}}Strlen);
             buffer += transfer->{{memberName}}Strlen;
         {% endfor %}

         //* Allocate space and write the non-value arguments in it.
         {% for member in members if member.annotation != "value" and member.length != "strlen" %}
             {% set memberName = as_varName(member.name) %}
             {
                 size_t memberLength = {{member_length(member, "record.")}};
                 auto memberBuffer = reinterpret_cast<{{member_transfer_type(member)}}*>(buffer);

                 buffer += memberLength * {{member_transfer_sizeof(member)}};
                 for (size_t i = 0; i < memberLength; ++i) {
                     {{serialize_member(member, "record." + memberName + "[i]", "memberBuffer[i]" )}}
                 }
             }
         {% endfor %}
     }

     //* Deserializes `transfer` into `record` getting more serialized data from `buffer` and `size`
     //* if needed, using `allocator` to store pointed-to values and `resolver` to translate object
     //* Ids to actual objects.
     DeserializeResult {{name}}Deserialize({{name}}* record, const {{name}}Transfer* transfer,
                                           const char** buffer, size_t* size, DeserializeAllocator* allocator, const ObjectIdResolver& resolver) {
         DAWN_UNUSED(allocator);
         DAWN_UNUSED(resolver);
         DAWN_UNUSED(buffer);
         DAWN_UNUSED(size);

         //* Handle special transfer members for methods
         {% if is_method %}
             {% if as_method.return_type.category == "object" %}
                 record->resultId = transfer->resultId;
                 record->resultSerial = transfer->resultSerial;
             {% endif %}

             ASSERT(transfer->commandId == {{Return}}WireCmd::{{name}});

             record->selfId = transfer->self;
             //* This conversion is done after the copying of result* and selfId: Deserialize
             //* guarantees they are filled even if there is an ID for an error object for the
             //* Maybe monad mechanism.
             DESERIALIZE_TRY(resolver.GetFromId(record->selfId, &record->self));

             //* The object resolver returns a success even if the object is null because the
             //* frontend is reponsible to validate that (null objects sometimes have special
             //* meanings). However it is never valid to call a method on a null object so we
             //* can error out in that case.
             if (record->self == nullptr) {
                 return DeserializeResult::FatalError;
             }
         {% endif %}

         {% if is_struct and as_struct.extensible %}
             record->nextInChain = nullptr;
         {% endif %}

         //* Value types are directly in the transfer record, objects being replaced with their IDs.
         {% for member in members if member.annotation == "value" %}
             {% set memberName = as_varName(member.name) %}
             {{deserialize_member(member, "transfer->" + memberName, "record->" + memberName)}}
         {% endfor %}

         //* Special handling of const char* that have their length embedded directly in the command
         {% for member in members if member.length == "strlen" %}
             {% set memberName = as_varName(member.name) %}
             {
                 size_t stringLength = transfer->{{memberName}}Strlen;
                 const char* stringInBuffer = nullptr;
                 DESERIALIZE_TRY(GetPtrFromBuffer(buffer, size, stringLength, &stringInBuffer));

                 char* copiedString = nullptr;
                 DESERIALIZE_TRY(GetSpace(allocator, stringLength + 1, &copiedString));
                 memcpy(copiedString, stringInBuffer, stringLength);
                 copiedString[stringLength] = '\0';
                 record->{{memberName}} = copiedString;
             }
         {% endfor %}

         //* Get extra buffer data, and copy pointed to values in extra allocated space.
         {% for member in members if member.annotation != "value" and member.length != "strlen" %}
             {% set memberName = as_varName(member.name) %}
             {
                 size_t memberLength = {{member_length(member, "record->")}};
                 auto memberBuffer = reinterpret_cast<const {{member_transfer_type(member)}}*>(buffer);
                 DESERIALIZE_TRY(GetPtrFromBuffer(buffer, size, memberLength, &memberBuffer));

                 {{as_cType(member.type.name)}}* copiedMembers = nullptr;
                 DESERIALIZE_TRY(GetSpace(allocator, memberLength, &copiedMembers));
                 record->{{memberName}} = copiedMembers;

                 for (size_t i = 0; i < memberLength; ++i) {
                     {{deserialize_member(member, "memberBuffer[i]", "copiedMembers[i]")}}
                 }
             }
         {% endfor %}

         return DeserializeResult::Success;
     }
 {% endmacro %}

 namespace dawn_wire {

     // Macro to simplify error handling, similar to DAWN_TRY but for DeserializeResult.
 #define DESERIALIZE_TRY(EXPR) \
     { \
         DeserializeResult exprResult = EXPR; \
         if (exprResult != DeserializeResult::Success) { \
             return exprResult; \
         } \
     }

     namespace {

         // Consumes from (buffer, size) enough memory to contain T[count] and return it in data.
         // Returns FatalError if not enough memory was available
         template <typename T>
         DeserializeResult GetPtrFromBuffer(const char** buffer, size_t* size, size_t count, const T** data) {
             // TODO(cwallez@chromium.org): For robustness we would need to handle overflows here.
             size_t totalSize = sizeof(T) * count;
             if (totalSize > *size) {
                 return DeserializeResult::FatalError;
             }

             *data = reinterpret_cast<const T*>(*buffer);
             *buffer += totalSize;
             *size -= totalSize;

             return DeserializeResult::Success;
         }

         // Allocates enough space from allocator to countain T[count] and return it in out.
         // Return FatalError if the allocator couldn't allocate the memory.
         template <typename T>
         DeserializeResult GetSpace(DeserializeAllocator* allocator, size_t count, T** out) {
             // TODO(cwallez@chromium.org): For robustness we would need to handle overflows here.
             size_t totalSize = sizeof(T) * count;
             *out = static_cast<T*>(allocator->GetSpace(totalSize));
             if (*out == nullptr) {
                 return DeserializeResult::FatalError;
             }

             return DeserializeResult::Success;
         }

         //* Output structure [de]serialization first because it is used by methods.
         {% for type in by_category["structure"] %}
             {% set name = as_cType(type.name) %}
             {{write_serialization_methods(name, type.members, as_struct=type)}}
         {% endfor %}

         // * Output [de]serialization helpers for methods
         {% for type in by_category["object"] %}
             {% for method in type.methods %}
                 {% set name = as_MethodSuffix(type.name, method.name) %}

                 using {{name}} = {{name}}Cmd;
                 {{write_serialization_methods(name, method.arguments, as_method=method)}}
             {% endfor %}
         {% endfor %}
     }  // anonymous namespace

     {% for type in by_category["object"] %}
         {% for method in type.methods %}
             {% set name = as_MethodSuffix(type.name, method.name) %}
             {% set Cmd = name + "Cmd" %}

             size_t {{Cmd}}::GetRequiredSize() const {
                 return sizeof({{name}}Transfer) + {{name}}GetExtraRequiredSize(*this);
             }

             void {{Cmd}}::Serialize(char* buffer, const ObjectIdProvider& objectIdProvider) const {
                 auto transfer = reinterpret_cast<{{name}}Transfer*>(buffer);
                 buffer += sizeof({{name}}Transfer);

                 {{name}}Serialize(*this, transfer, buffer, objectIdProvider);
             }

             DeserializeResult {{Cmd}}::Deserialize(const char** buffer, size_t* size, DeserializeAllocator* allocator, const ObjectIdResolver& resolver) {
                 const {{name}}Transfer* transfer = nullptr;
                 DESERIALIZE_TRY(GetPtrFromBuffer(buffer, size, 1, &transfer));

                 return {{name}}Deserialize(this, transfer, buffer, size, allocator, resolver);
             }
         {% endfor %}
     {% endfor %}

 }  // namespace dawn_wire
	//* Copyright 2017 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.

	#include "dawn_wire/WireCmd.h"

	#include "common/Assert.h"

	#include <cstring>

	//* Helper macros so that the main [de]serialization functions can be written in a generic manner.

	//* Outputs an rvalue that's the number of elements a pointer member points to.
	{% macro member_length(member, record_accessor) -%}
	{%- if member.length == "constant" -%}
	{{member.constant_length}}
	{%- else -%}
	{{record_accessor}}{{as_varName(member.length.name)}}
	{%- endif -%}
	{%- endmacro %}

	//* Outputs the type that will be used on the wire for the member
	{% macro member_transfer_type(member) -%}
	{%- if member.type.category == "object" -%}
	ObjectId
	{%- elif member.type.category == "structure" -%}
	{{as_cType(member.type.name)}}Transfer
	{%- else -%}
	{{as_cType(member.type.name)}}
	{%- endif -%}
	{%- endmacro %}

	//* Outputs the size of one element of the type that will be used on the wire for the member
	{% macro member_transfer_sizeof(member) -%}
	sizeof({{member_transfer_type(member)}})
	{%- endmacro %}

	//* Outputs the serialization code to put `in` in `out`
	{% macro serialize_member(member, in, out) %}
	{%- if member.type.category == "object" -%}
	{{out}} = provider.GetId({{in}});
	{% elif member.type.category == "structure"%}
	{{as_cType(member.type.name)}}Serialize({{in}}, &{{out}}, buffer, provider);
	{%- else -%}
	{{out}} = {{in}};
	{%- endif -%}
	{% endmacro %}

	//* Outputs the deserialization code to put `in` in `out`
	{% macro deserialize_member(member, in, out) %}
	{%- if member.type.category == "object" -%}
	DESERIALIZE_TRY(resolver.GetFromId({{in}}, &{{out}}));
	{% elif member.type.category == "structure"%}
	DESERIALIZE_TRY({{as_cType(member.type.name)}}Deserialize(&{{out}}, &{{in}}, buffer, size, allocator, resolver));
	{%- else -%}
	{{out}} = {{in}};
	{%- endif -%}
	{% endmacro %}

	//* The main [de]serialization macro

	//* Methods are very similar to structures that have one member corresponding to each arguments.
	//* This macro takes advantage of the similarity to output [de]serialization code for a record
	//* that is either a structure or a method, with some special cases for each.
	{% macro write_serialization_methods(name, members, as_method=None, as_struct=None, is_return_command=False) %}
	{% set Return = "Return" if is_return_command else "" %}
	{% set is_method = as_method != None %}
	{% set is_struct = as_struct != None %}

	//* Structure for the wire format of each of the records. Members that are values
	//* are embedded directly in the structure. Other members are assumed to be in the
	//* memory directly following the structure in the buffer.
	struct {{name}}Transfer {
	{% if is_method %}
	//* Start the transfer structure with the command ID, so that casting to WireCmd gives the ID.
	{{Return}}WireCmd commandId;

	//* Methods always have an implicit "self" argument.
	ObjectId self;

	//* Methods that return objects need to declare to the server which ID will be used for the
	//* return value.
	{% if as_method.return_type.category == "object" %}
	ObjectId resultId;
	ObjectSerial resultSerial;
	{% endif %}
	{% endif %}

	//* Value types are directly in the command, objects being replaced with their IDs.
	{% for member in members if member.annotation == "value" %}
	{{member_transfer_type(member)}} {{as_varName(member.name)}};
	{% endfor %}

	//* const char* have their length embedded directly in the command.
	{% for member in members if member.length == "strlen" %}
	size_t {{as_varName(member.name)}}Strlen;
	{% endfor %}
	};

	//* Returns the required transfer size for `record` in addition to the transfer structure.
	size_t {{name}}GetExtraRequiredSize(const {{name}}& record) {
	DAWN_UNUSED(record);

	size_t result = 0;

	//* Special handling of const char* that have their length embedded directly in the command
	{% for member in members if member.length == "strlen" %}
	result += std::strlen(record.{{as_varName(member.name)}});
	{% endfor %}

	//* Gather how much space will be needed for pointer members.
	{% for member in members if member.annotation != "value" and member.length != "strlen" %}
	{
	size_t memberLength = {{member_length(member, "record.")}};
	result += memberLength * {{member_transfer_sizeof(member)}};

	//* Structures might contain more pointers so we need to add their extra size as well.
	{% if member.type.category == "structure" %}
	for (size_t i = 0; i < memberLength; ++i) {
	result += {{as_cType(member.type.name)}}GetExtraRequiredSize(record.{{as_varName(member.name)}}[i]);
	}
	{% endif %}
	}
	{% endfor %}

	return result;
	}
	// GetExtraRequiredSize isn't used for structures that are value members of other structures
	// because we assume they cannot contain pointers themselves.
	DAWN_UNUSED_FUNC({{name}}GetExtraRequiredSize);

	//* Serializes `record` into `transfer`, using `buffer` to get more space for pointed-to data
	//* and `provider` to serialize objects.
	void {{name}}Serialize(const {{name}}& record, {{name}}Transfer* transfer,
	char* buffer, const ObjectIdProvider& provider) {
	DAWN_UNUSED(provider);
	DAWN_UNUSED(buffer);

	//* Handle special transfer members of methods.
	{% if is_method %}
	{% if as_method.return_type.category == "object" %}
	transfer->resultId = record.resultId;
	transfer->resultSerial = record.resultSerial;
	{% endif %}

	transfer->commandId = {{Return}}WireCmd::{{name}};
	transfer->self = provider.GetId(record.self);
	{% endif %}

	//* Value types are directly in the transfer record, objects being replaced with their IDs.
	{% for member in members if member.annotation == "value" %}
	{% set memberName = as_varName(member.name) %}
	{{serialize_member(member, "record." + memberName, "transfer->" + memberName)}}
	{% endfor %}

	//* Special handling of const char* that have their length embedded directly in the command
	{% for member in members if member.length == "strlen" %}
	{% set memberName = as_varName(member.name) %}
	transfer->{{memberName}}Strlen = std::strlen(record.{{memberName}});

	memcpy(buffer, record.{{memberName}}, transfer->{{memberName}}Strlen);
	buffer += transfer->{{memberName}}Strlen;
	{% endfor %}

	//* Allocate space and write the non-value arguments in it.
	{% for member in members if member.annotation != "value" and member.length != "strlen" %}
	{% set memberName = as_varName(member.name) %}
	{
	size_t memberLength = {{member_length(member, "record.")}};
	auto memberBuffer = reinterpret_cast<{{member_transfer_type(member)}}*>(buffer);

	buffer += memberLength * {{member_transfer_sizeof(member)}};
	for (size_t i = 0; i < memberLength; ++i) {
	{{serialize_member(member, "record." + memberName + "[i]", "memberBuffer[i]" )}}
	}
	}
	{% endfor %}
	}

	//* Deserializes `transfer` into `record` getting more serialized data from `buffer` and `size`
	//* if needed, using `allocator` to store pointed-to values and `resolver` to translate object
	//* Ids to actual objects.
	DeserializeResult {{name}}Deserialize({{name}}* record, const {{name}}Transfer* transfer,
	const char** buffer, size_t* size, DeserializeAllocator* allocator, const ObjectIdResolver& resolver) {
	DAWN_UNUSED(allocator);
	DAWN_UNUSED(resolver);
	DAWN_UNUSED(buffer);
	DAWN_UNUSED(size);

	//* Handle special transfer members for methods
	{% if is_method %}
	{% if as_method.return_type.category == "object" %}
	record->resultId = transfer->resultId;
	record->resultSerial = transfer->resultSerial;
	{% endif %}

	ASSERT(transfer->commandId == {{Return}}WireCmd::{{name}});

	record->selfId = transfer->self;
	//* This conversion is done after the copying of result* and selfId: Deserialize
	//* guarantees they are filled even if there is an ID for an error object for the
	//* Maybe monad mechanism.
	DESERIALIZE_TRY(resolver.GetFromId(record->selfId, &record->self));

	//* The object resolver returns a success even if the object is null because the
	//* frontend is reponsible to validate that (null objects sometimes have special
	//* meanings). However it is never valid to call a method on a null object so we
	//* can error out in that case.
	if (record->self == nullptr) {
	return DeserializeResult::FatalError;
	}
	{% endif %}

	{% if is_struct and as_struct.extensible %}
	record->nextInChain = nullptr;
	{% endif %}

	//* Value types are directly in the transfer record, objects being replaced with their IDs.
	{% for member in members if member.annotation == "value" %}
	{% set memberName = as_varName(member.name) %}
	{{deserialize_member(member, "transfer->" + memberName, "record->" + memberName)}}
	{% endfor %}

	//* Special handling of const char* that have their length embedded directly in the command
	{% for member in members if member.length == "strlen" %}
	{% set memberName = as_varName(member.name) %}
	{
	size_t stringLength = transfer->{{memberName}}Strlen;
	const char* stringInBuffer = nullptr;
	DESERIALIZE_TRY(GetPtrFromBuffer(buffer, size, stringLength, &stringInBuffer));

	char* copiedString = nullptr;
	DESERIALIZE_TRY(GetSpace(allocator, stringLength + 1, &copiedString));
	memcpy(copiedString, stringInBuffer, stringLength);
	copiedString[stringLength] = '\0';
	record->{{memberName}} = copiedString;
	}
	{% endfor %}

	//* Get extra buffer data, and copy pointed to values in extra allocated space.
	{% for member in members if member.annotation != "value" and member.length != "strlen" %}
	{% set memberName = as_varName(member.name) %}
	{
	size_t memberLength = {{member_length(member, "record->")}};
	auto memberBuffer = reinterpret_cast<const {{member_transfer_type(member)}}*>(buffer);
	DESERIALIZE_TRY(GetPtrFromBuffer(buffer, size, memberLength, &memberBuffer));

	{{as_cType(member.type.name)}}* copiedMembers = nullptr;
	DESERIALIZE_TRY(GetSpace(allocator, memberLength, &copiedMembers));
	record->{{memberName}} = copiedMembers;

	for (size_t i = 0; i < memberLength; ++i) {
	{{deserialize_member(member, "memberBuffer[i]", "copiedMembers[i]")}}
	}
	}
	{% endfor %}

	return DeserializeResult::Success;
	}
	{% endmacro %}

	namespace dawn_wire {

	// Macro to simplify error handling, similar to DAWN_TRY but for DeserializeResult.
	#define DESERIALIZE_TRY(EXPR) \
	{ \
	DeserializeResult exprResult = EXPR; \
	if (exprResult != DeserializeResult::Success) { \
	return exprResult; \
	} \
	}

	namespace {

	// Consumes from (buffer, size) enough memory to contain T[count] and return it in data.
	// Returns FatalError if not enough memory was available
	template <typename T>
	DeserializeResult GetPtrFromBuffer(const char** buffer, size_t* size, size_t count, const T** data) {
	// TODO(cwallez@chromium.org): For robustness we would need to handle overflows here.
	size_t totalSize = sizeof(T) * count;
	if (totalSize > *size) {
	return DeserializeResult::FatalError;
	}

	data = reinterpret_cast<const T>(*buffer);
	*buffer += totalSize;
	*size -= totalSize;

	return DeserializeResult::Success;
	}

	// Allocates enough space from allocator to countain T[count] and return it in out.
	// Return FatalError if the allocator couldn't allocate the memory.
	template <typename T>
	DeserializeResult GetSpace(DeserializeAllocator* allocator, size_t count, T** out) {
	// TODO(cwallez@chromium.org): For robustness we would need to handle overflows here.
	size_t totalSize = sizeof(T) * count;
	out = static_cast<T>(allocator->GetSpace(totalSize));
	if (*out == nullptr) {
	return DeserializeResult::FatalError;
	}

	return DeserializeResult::Success;
	}

	//* Output structure [de]serialization first because it is used by methods.
	{% for type in by_category["structure"] %}
	{% set name = as_cType(type.name) %}
	{{write_serialization_methods(name, type.members, as_struct=type)}}
	{% endfor %}

	// * Output [de]serialization helpers for methods
	{% for type in by_category["object"] %}
	{% for method in type.methods %}
	{% set name = as_MethodSuffix(type.name, method.name) %}

	using {{name}} = {{name}}Cmd;
	{{write_serialization_methods(name, method.arguments, as_method=method)}}
	{% endfor %}
	{% endfor %}
	} // anonymous namespace

	{% for type in by_category["object"] %}
	{% for method in type.methods %}
	{% set name = as_MethodSuffix(type.name, method.name) %}
	{% set Cmd = name + "Cmd" %}

	size_t {{Cmd}}::GetRequiredSize() const {
	return sizeof({{name}}Transfer) + {{name}}GetExtraRequiredSize(*this);
	}

	void {{Cmd}}::Serialize(char* buffer, const ObjectIdProvider& objectIdProvider) const {
	auto transfer = reinterpret_cast<{{name}}Transfer*>(buffer);
	buffer += sizeof({{name}}Transfer);

	{{name}}Serialize(*this, transfer, buffer, objectIdProvider);
	}

	DeserializeResult {{Cmd}}::Deserialize(const char** buffer, size_t* size, DeserializeAllocator* allocator, const ObjectIdResolver& resolver) {
	const {{name}}Transfer* transfer = nullptr;
	DESERIALIZE_TRY(GetPtrFromBuffer(buffer, size, 1, &transfer));

	return {{name}}Deserialize(this, transfer, buffer, size, allocator, resolver);
	}
	{% endfor %}
	{% endfor %}

	} // namespace dawn_wire