dawn-cmake/generator/templates/dawn_wire/WireCmd.cpp

441 lines
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C++

//* 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_autogen.h"
#include "common/Assert.h"
#include <cstring>
#include <limits>
//* 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" -%}
{%- set Optional = "Optional" if member.optional else "" -%}
{{out}} = provider.Get{{Optional}}Id({{in}});
{% elif member.type.category == "structure"%}
{%- set Provider = ", provider" if member.type.has_dawn_object else "" -%}
{% if member.annotation == "const*const*" %}
{{as_cType(member.type.name)}}Serialize(*{{in}}, &{{out}}, buffer{{Provider}});
{% else %}
{{as_cType(member.type.name)}}Serialize({{in}}, &{{out}}, buffer{{Provider}});
{% endif %}
{%- 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" -%}
{%- set Optional = "Optional" if member.optional else "" -%}
DESERIALIZE_TRY(resolver.Get{{Optional}}FromId({{in}}, &{{out}}));
{%- elif member.type.category == "structure" -%}
DESERIALIZE_TRY({{as_cType(member.type.name)}}Deserialize(&{{out}}, &{{in}}, buffer, size, allocator
{%- if member.type.has_dawn_object -%}
, resolver
{%- endif -%}
));
{%- 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_record_serialization_helpers(record, name, members, is_cmd=False, is_return_command=False) %}
{% set Return = "Return" if is_return_command else "" %}
{% set Cmd = "Cmd" if is_cmd else "" %}
//* 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 {{Return}}{{name}}Transfer {
{% if is_cmd %}
//* Start the transfer structure with the command ID, so that casting to WireCmd gives the ID.
{{Return}}WireCmd commandId;
{% 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 %}
{% for member in members if member.annotation != "value" and member.type.category != "object" %}
bool has_{{as_varName(member.name)}};
{% endfor %}
};
//* Returns the required transfer size for `record` in addition to the transfer structure.
DAWN_DECLARE_UNUSED size_t {{Return}}{{name}}GetExtraRequiredSize(const {{Return}}{{name}}{{Cmd}}& 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" %}
{% set memberName = as_varName(member.name) %}
{% if member.optional %}
bool has_{{memberName}} = record.{{memberName}} != nullptr;
if (has_{{memberName}})
{% endif %}
{
result += std::strlen(record.{{memberName}});
}
{% endfor %}
//* Gather how much space will be needed for pointer members.
{% for member in members if member.length != "strlen" and not member.skip_serialize %}
{% if member.type.category != "object" and member.optional %}
if (record.{{as_varName(member.name)}} != nullptr)
{% endif %}
{
{% if member.annotation != "value" %}
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) {
{% if member.annotation == "const*const*" %}
result += {{as_cType(member.type.name)}}GetExtraRequiredSize(*record.{{as_varName(member.name)}}[i]);
{% else %}
{{assert(member.annotation == "const*")}}
result += {{as_cType(member.type.name)}}GetExtraRequiredSize(record.{{as_varName(member.name)}}[i]);
{% endif %}
}
{% endif %}
{% elif member.type.category == "structure" %}
result += {{as_cType(member.type.name)}}GetExtraRequiredSize(record.{{as_varName(member.name)}});
{% 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({{Return}}{{name}}GetExtraRequiredSize);
//* Serializes `record` into `transfer`, using `buffer` to get more space for pointed-to data
//* and `provider` to serialize objects.
DAWN_DECLARE_UNUSED void {{Return}}{{name}}Serialize(const {{Return}}{{name}}{{Cmd}}& record, {{Return}}{{name}}Transfer* transfer,
char** buffer
{%- if record.has_dawn_object -%}
, const ObjectIdProvider& provider
{%- endif -%}
) {
DAWN_UNUSED(buffer);
//* Handle special transfer members of methods.
{% if is_cmd %}
transfer->commandId = {{Return}}WireCmd::{{name}};
{% 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) %}
bool has_{{memberName}} = record.{{memberName}} != nullptr;
transfer->has_{{memberName}} = has_{{memberName}};
{% if member.optional %}
if (has_{{memberName}})
{% endif %}
{
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" and not member.skip_serialize %}
{% set memberName = as_varName(member.name) %}
{% if member.type.category != "object" and member.optional %}
bool has_{{memberName}} = record.{{memberName}} != nullptr;
transfer->has_{{memberName}} = has_{{memberName}};
if (has_{{memberName}})
{% endif %}
{
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 %}
}
DAWN_UNUSED_FUNC({{Return}}{{name}}Serialize);
//* 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.
DAWN_DECLARE_UNUSED DeserializeResult {{Return}}{{name}}Deserialize({{Return}}{{name}}{{Cmd}}* record, const {{Return}}{{name}}Transfer* transfer,
const char** buffer, size_t* size, DeserializeAllocator* allocator
{%- if record.has_dawn_object -%}
, const ObjectIdResolver& resolver
{%- endif -%}
) {
DAWN_UNUSED(allocator);
DAWN_UNUSED(buffer);
DAWN_UNUSED(size);
{% if is_cmd %}
ASSERT(transfer->commandId == {{Return}}WireCmd::{{name}});
{% endif %}
{% if record.extensible %}
record->nextInChain = nullptr;
{% endif %}
{% if record.derived_method %}
record->selfId = transfer->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) %}
{{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) %}
bool has_{{memberName}} = transfer->has_{{memberName}};
if (has_{{memberName}})
{
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;
} else {
record->{{memberName}} = nullptr;
}
{% 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) %}
{% if member.type.category != "object" and member.optional %}
bool has_{{memberName}} = transfer->has_{{memberName}};
record->{{memberName}} = nullptr;
if (has_{{memberName}})
{% endif %}
{
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));
{% if member.annotation == "const*const*" %}
{{as_cType(member.type.name)}}** pointerArray = nullptr;
DESERIALIZE_TRY(GetSpace(allocator, memberLength, &pointerArray));
for (size_t i = 0; i < memberLength; ++i) {
pointerArray[i] = &copiedMembers[i];
}
record->{{memberName}} = pointerArray;
{% else %}
record->{{memberName}} = copiedMembers;
{% endif %}
for (size_t i = 0; i < memberLength; ++i) {
{{deserialize_member(member, "memberBuffer[i]", "copiedMembers[i]")}}
}
}
{% endfor %}
return DeserializeResult::Success;
}
DAWN_UNUSED_FUNC({{Return}}{{name}}Deserialize);
{% endmacro %}
{% macro write_command_serialization_methods(command, is_return) %}
{% set Return = "Return" if is_return else "" %}
{% set Name = Return + command.name.CamelCase() %}
{% set Cmd = Name + "Cmd" %}
size_t {{Cmd}}::GetRequiredSize() const {
size_t size = sizeof({{Name}}Transfer) + {{Name}}GetExtraRequiredSize(*this);
return size;
}
void {{Cmd}}::Serialize(char* buffer
{%- if command.has_dawn_object -%}
, const ObjectIdProvider& objectIdProvider
{%- endif -%}
) const {
auto transfer = reinterpret_cast<{{Name}}Transfer*>(buffer);
buffer += sizeof({{Name}}Transfer);
{{Name}}Serialize(*this, transfer, &buffer
{%- if command.has_dawn_object -%}
, objectIdProvider
{%- endif -%}
);
}
DeserializeResult {{Cmd}}::Deserialize(const char** buffer, size_t* size, DeserializeAllocator* allocator
{%- if command.has_dawn_object -%}
, const ObjectIdResolver& resolver
{%- endif -%}
) {
const {{Name}}Transfer* transfer = nullptr;
DESERIALIZE_TRY(GetPtrFromBuffer(buffer, size, 1, &transfer));
return {{Name}}Deserialize(this, transfer, buffer, size, allocator
{%- if command.has_dawn_object -%}
, resolver
{%- endif -%}
);
}
{% 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) {
constexpr size_t kMaxCountWithoutOverflows = std::numeric_limits<size_t>::max() / sizeof(T);
if (count > kMaxCountWithoutOverflows) {
return DeserializeResult::FatalError;
}
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) {
constexpr size_t kMaxCountWithoutOverflows = std::numeric_limits<size_t>::max() / sizeof(T);
if (count > kMaxCountWithoutOverflows) {
return DeserializeResult::FatalError;
}
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 commands.
{% for type in by_category["structure"] %}
{% set name = as_cType(type.name) %}
{% if type.name.CamelCase() not in client_side_structures %}
{{write_record_serialization_helpers(type, name, type.members,
is_cmd=False)}}
{% endif %}
{% endfor %}
//* Output [de]serialization helpers for commands
{% for command in cmd_records["command"] %}
{% set name = command.name.CamelCase() %}
{{write_record_serialization_helpers(command, name, command.members,
is_cmd=True)}}
{% endfor %}
//* Output [de]serialization helpers for return commands
{% for command in cmd_records["return command"] %}
{% set name = command.name.CamelCase() %}
{{write_record_serialization_helpers(command, name, command.members,
is_cmd=True, is_return_command=True)}}
{% endfor %}
} // anonymous namespace
{% for command in cmd_records["command"] %}
{{ write_command_serialization_methods(command, False) }}
{% endfor %}
{% for command in cmd_records["return command"] %}
{{ write_command_serialization_methods(command, True) }}
{% endfor %}
} // namespace dawn_wire