The
qtprotobufgen
tool can be used to generate Qt Protobuf classes from a protobuf schema. The tool is provided by the CMake
Qt6::ProtobufTools
package. It works as an extension to Google's
protoc
工具。
find_package(Qt6 COMPONENTS ProtobufTools REQUIRED)
Qt provides CMake functions that ease the use of the
qtprotobufgen
tool. When using CMake as a build tool you should prefer using the
Qt CMake API
. For build systems other than CMake, adapt the commands described in
Running manually
.
注意: there is no explicit support for building gRPC and Protobuf applications using the Qt GRPC module with qmake .
The following CMake commands integrate a protobuf schema into a Qt project.
Generates Qt-based C++ source code using a protobuf schema |
Usually
qtprotobufgen
would be invoked through CMake using the
qt_add_protobuf
宏。
cmake_minimum_required(VERSION 3.16...3.22) project(MyThings) find_package(Qt6 REQUIRED COMPONENTS Protobuf) qt_standard_project_setup() qt_add_protobuf(MyMessages GENERATE_PACKAGE_SUBFOLDERS PROTO_FILES path/to/message.proto path/to/other_message.proto PROTO_INCLUDES /path/to/proto/include ) qt_add_executable(MyApp main.cpp) target_link_libraries(MyApp PRIVATE MyMessages)
In the example above, we generate a library called
MyMessages
, which contains the message types defined in the paths passed to the
PROTO_FILES
选项。
GENERATE_PACKAGE_SUBFOLDERS
option to generate a folder structure for the generated files. And the
PROTO_INCLUDES
option tells protoc to look for dependencies or imports in the specified directories. We create a target for an executable called
MyApp
, which we link to the
MyMessages
库。
protoc --plugin=protoc-gen-qtprotobuf=<path/to/bin/>qtprotobufgen \ --qtprotobuf_out="[<options>:]<output_dir>" \ [--qtprotobuf_opt="<options>"] \ [-I/extra/proto/include/path] \ <protofile>.proto
The
options
argument is a semicolon-separated list of
Options
. It can be passed in
two
different ways. Either by prepending to the options to the output_dir argument, delimited by a colon. Or through a separate argument,
--qtprotobuf_opt
. You also can pass the corresponding keys as the
QT_PROTOBUF_OPTIONS
environment variable. Keys need to be presented as a semicolon-separated list:
export QT_PROTOBUF_OPTIONS="COPY_COMMENTS;GENERATE_PACKAGE_SUBFOLDERS;EXTRA_NAMESPACE=MyTopLevelNamespace"
The generator supports options that can be provided to tune generation. Options have direct aliases in the qt_add_protobuf function. The following options are supported:
COPY_COMMENTS
copies comments from
.proto
files. If provided in the parameter list, comments related to messages and fields are copied to generated header files.
GENERATE_PACKAGE_SUBFOLDERS
generates a folder structure for the generated files matching the
.proto
file's package name. For example,
package io.qt.test;
would put the generated files into
io/qt/test/
.
EXTRA_NAMESPACE
is an optional namespace that will be used for the generated classes. The classes are always generated in a namespace whose name is the same as the package name specified in the
.proto
file. If this option is used, then everything will be nested inside the extra namespace.
EXPORT_MACRO
is the base name of the symbol export macro used for the generated code. The generated macro name is constructed as
QPB_<EXPORT_MACRO>_EXPORT
. If the option is not set, the macro is not generated.
QML_URI
启用
QProtobufMessage
types in the QML context by registering them in a QML module via the provided
URI
import path. The
URI
option will be used in the line of the generated
qmldir
file, and also used to form the target path by replacing dots with forward slashes.
注意:
读取
识别模块
for further in-depth discussion of the
URI
.