zproject - CLASS Project Generator
- Setup your project environment
- Project dependencies
- Modifying generated files in an already existent project
- Sample API model
- Supported API Model Attributes
- API Types
- Generate API model from C header files
zproject is a community project, like most ZeroMQ projects, built using the C4.1 process, and licensed under MPL v2. It solves the Makefile problem really well. It is unashamedly for C, and more pointedly, for that modern C dialect we call CLASS. CLASS is the Minecraft of C: fun, easy, playful, mind-opening, and social. Read more about it hintjens#79.
zproject grew out of the work that has been done to automatically generate the build environment in CZMQ. It allows to share these automations with other projects like zyre, malamute or hydra and at the same time keep everything in sync.
Scope and Goals
zproject has these primary goals:
- generate cross-platform build environments.
- generate CLASS (ZeroMQ RFC/21) compliant header and source skeletons for new classes.
- generate a public header file for your library so it can be easily included by others.
- generate stubs for man page documentation which uses the comment based approach from CZMQ.
All you need is a project.xml file in the project's root directory which is your
One file to rule them all
At least the following build environments are currently supported:
- Visual Studio
Thanks to the ZeroMQ community, you can do all the heavy lifting in C and then easily generate bindings in the following languages:
- Java (JNI)
The language bindings are minimal, meant to be wrapped in a handwritten idiomatic layer later.
zproject uses the universal code generator called GSL to process its XML inputs
and create its outputs. Before you start you'll need to install GSL
(https://github.com/imatix/gsl) on your system.
git clone https://github.com/imatix/gsl.git cd gsl/src make make install
GSL must be able to find the zproject resources on your system. Therefore you'll
need to install them. The following will install the zproject files to
git clone https://github.com/zeromq/zproject.git cd zproject ./autogen.sh ./configure make make install
NB: You may need to use the
sudo command when running
make install to elevate your privileges, e.g.
sudo make install
NB: If you don't have superuser rights on a system you'll have to make sure zproject's gsl scripts can be found on your PATH.
Setup your project environment
The easiest way to start is to create a minimal project.xml.
<project script = "zproject.gsl"> <use project = "czmq" /> <main name = "hello" private = "1" /> </project>
Once you're done you can create your project's build environment and start compiling:
gsl project.xml autogen.sh configure.sh make
NB: To get a more comprehensive example copy zproject's project.xml. It contains all possible configurations and according documentation.
Licensing your project is important thus you'll need a license file. Here's an overview that might help you decide to choose a license. zproject allows you to add an appropriate disclaimer of your license as a xml file, e.g. license.xml:
<license> Your license disclaimer goes here! </license>
This disclaimer can be included in your project.xml and is used whenever zproject is generating new files e.g. CLASS skeletons or bindings.
<include filename = "license.xml" />
project.xml contains an extensive description of the available configuration: The following snippet is taken from the
<!-- The project.xml generates build environments for: autotools GNU build system (default) cmake CMake build system (default) android Native shared library for Android cygwin Cygwin build system debian packaging for Debian docker packaging for Docker java Java JNI binding java-msvc MSVC builds for Java JNI binding mingw32 Mingw32 build system nuget Packaging for NuGet python Python binding qml QML binding qt Qt binding redhat Packaging for RedHat ruby Ruby binding travis Travis CI scripts <option name="travis_distcheck" value="0" /> will disable run of make distcheck vs2008 Microsoft Visual Studio 2008 vs2010 Microsoft Visual Studio 2010 vs2012 Microsoft Visual Studio 2012 vs2013 Microsoft Visual Studio 2013 vs2015 Microsoft Visual Studio 2015 Classes are automatically added to all build environments. Further as you add new classes to your project you can generate skeleton header and source files according to http://rfc.zeromq.org/spec:21. script := The gsl script to generate all the stuff !!! DO NOT CHANGE !!! name := The name of your project (optional) description := A short description for your project (optional) email := The email address where to reach you (optional) repository := git repository holding project (optional) --> <project script = "zproject.gsl" name = "zproject" email = "firstname.lastname@example.org" license = "MPLv2" url = "https://github.com/zeromq/zproject" repository = "https://github.com/zeromq/zproject"> <!-- Includes are processed first, so XML in included files will be part of the XML tree --> <include filename = "license.xml" /> <!-- Current version of your project. This will be used to package your distribution --> <version major = "1" minor = "1" patch = "0" /> <!-- Current libtool ABI version of your project's shared library. Start at 0:0:0 and see: http://www.gnu.org/software/libtool/manual/html_node/Updating-version-info.html for details on how/when to increment it. If not defined 0:0:0 will be used. <abi current = "0" revision = "0" age = "0" /> --> <!-- Specify which other projects this depends on. These projects must be known by zproject, and the list of known projects is maintained in the zproject_known_projects.xml model. You need not specify subdependencies if they are implied. Dependencies that support the autotools build system are automatically built by travis ci if you supply a git repository or a tarball URI. Set type to "runtime" to have the packages install-depend on it rather than build-depend (default type is "build"). The travis ci will use the installed packages when building instead of rebuilding if available. <use project = "zyre" min_major= "1" min_minor = "1" min_patch = "0" /> <use project = "czmq" min_major= "3" min_minor = "0" min_patch = "2" next_incompatible_major = "4" /> <use project = "uuid" optional= "1" implied = "1" /> <use project = "myfirstlib" repository = "http://myfirstlib.org/myfirstlib.git" /> <use project = "mysecondlib" tarball = "http://mysecondlib.org/mysecondlib-1.2.3.tar.gz" /> <use project = "lua-5.1" am_lib_macro = "LUA_5_1" tarball = "..." /> --> <use project = "gsl" type = "runtime" /> <!-- Header Files name := The name the header file to include without file ending <header name = "myproject_prelude" /> --> <!-- Classes, if the class header or source file doesn't exist, this will generate a skeletons for them. Use private = "1" for internal classes Use selftest = "0" to not generate selftest code <class name = "myclass">Public class description</class> <class name = "someother" private = "1">Private class description</class> --> <!-- Actors, are built using the simple actor framework from czmq. If the actors class header or source file doesn't exist, this will generate a skeleton for them. The generated test method of the actor will teach you how to use them. Also have a look at the CZMQ docs to learn more about actors. Use selftest = "0" to not generate selftest code <actor name = "myactor">Public actor description</actor> <actor name = "someactor" private = "1">Private actor description</actor> --> <!-- Main programs built by the project use private = "1" for internal tools <main name = "progname">Exported public tool</main> <main name = "progname" private = "1">Internal tool</main> <main name = "progname" service = "1">Installed as system service, single-instance</main> <main name = "progname" service = "2">Installed as system service, multi-instance (@)</main> <main name = "progname" service = "3">Installed as system service, both single and multi-instance (@)</main> <main name = "progname" timer = "3">Installed as system timer unit, both single and multi-instance (@)</main> <main name = "progname" service = "1" timer = "1">Installed with both system timer and service units, single-instance - probably the former triggers the latter occasionally</main> Note that <bin> tags for secondary distributed programs (or scripts) now also support the service and timer attributes with same semantics. --> <!-- Benchmark programs built by the project <bench name = "benchname">Benchmark for class/function...</main> --> <!-- Models that we build using GSL. This will generate a 'make code' target to build the models. <model name = "sockopts" /> <model name = "zgossip" /> <model name = "zgossip_msg" /> If a model should be generated using a specific gsl script, this can be set through the script attribute: <model name = "hydra_msg" script = "zproto_codec_java.gsl" /> Additional parameters to the script can be set via nested param elements: <model name = "hydra_msg" script = "zproto_codec_java.gsl"> <param name = "root_path" value = "../main" /> </model> --> <!-- Other source files that we need to package <extra name = "some_resource" /> --> <!-- Specify targets to build; autotools and cmake are built in all cases. <target name = "cmake" /> <target name = "autotools" /> --> <!-- Targets may be customizable with their own options --> <target name = "cmake"> <option name = "single setting" value = "value" /> <option name = "list setting"> <item name = "item name" value = "item value" /> </option> </target> <target name = "obs" /> <target name = "debian" /> <target name = "redhat" /> <!-- In order loaded by zproject.gsl --> <bin name = "zproject.gsl" /> <bin name = "zproject_projects.gsl" /> <bin name = "zproject_class_api.gsl" /> <!-- Mainline generation code --> <bin name = "zproject_skeletons.gsl" /> <bin name = "zproject_bench.gsl" /> <bin name = "zproject_class.gsl" /> <bin name = "zproject_git.gsl" /> <bin name = "zproject_valgrind.gsl" /> <!-- Targets --> <bin name = "zproject_android.gsl" /> <bin name = "zproject_autotools.gsl" /> <bin name = "zproject_cmake.gsl" /> <bin name = "zproject_cygwin.gsl" /> <bin name = "zproject_debian.gsl" /> <bin name = "zproject_docker.gsl" /> <bin name = "zproject_gyp.gsl" /> <bin name = "zproject_java.gsl" /> <bin name = "zproject_java_lib.gsl" /> <bin name = "zproject_java_msvc.gsl" /> <bin name = "zproject_lua_ffi.gsl" /> <bin name = "zproject_mingw32.gsl" /> <bin name = "zproject_nodejs.gsl" /> <bin name = "zproject_nuget.gsl" /> <bin name = "zproject_obs.gsl" /> <bin name = "zproject_python.gsl" /> <bin name = "zproject_python_cffi.gsl" /> <bin name = "zproject_python_cffi2.gsl" /> <bin name = "zproject_qml.gsl" /> <bin name = "zproject_qt.gsl" /> <bin name = "zproject_redhat.gsl" /> <bin name = "zproject_rpi.gsl" /> <bin name = "zproject_ruby.gsl" /> <bin name = "zproject_systemd.gsl" /> <bin name = "zproject_travis.gsl" /> <bin name = "zproject_vagrant.gsl" /> <bin name = "zproject_vs2008.gsl" /> <bin name = "zproject_vs20xx.gsl" /> <bin name = "zproject_vs20xx_props.gsl" /> <bin name = "zproject_known_projects.xml" /> <bin name = "mkapi.py" /> <bin name = "fake_cpp" /> </project>
use element defines project dependencies.
Model is described in
<known_projects> <!-- ZeroMQ Projects --> <!-- Problem: naming style is inconsistent we sometimes use libxxx and sometimes xxx; the git repo name is unpredictable; sometimes we override with the prefix and sometimes with libname. Proposed solution: project name should always be git repo name; prefix and libname should always be specified. For compatibility we can define aliases. E.g.: Also, 'cmake name' is target specific and must go. Suggested model: <use project = "libzmq" required master = "https://github.com/zeromq" required libname = "libzmq" default = lib<prefix> prefix = "zmq" default = project test = "zmq_init" required same as AC_CHECK_LIB in autoconf release = "<tagname>" default = "master" abi = "version" default = "0:0:0" header = "<filename>" default = <prefix>.h language = "C|C++" default = "C" optional = "1" default = "0" debian_name = "libzmq5-dev" default = lib<name>-dev redhat_name = "zeromq-devel" default = <name>-devel <add_config_opts>--with-dep1=nuance</add_config_opts> <add_config_opts>--enable-feature2</add_config_opts> </use> --> <use project = "libzmq" prefix = "zmq" debian_name = "libzmq3-dev" redhat_name = "zeromq-devel" repository = "https://github.com/zeromq/libzmq.git" test = "zmq_init" /> <!-- Note: if your project requires an older CZMQ (e.g. if you need `release = "v3.0.2"`), you may need to `test = "zctx_test"`. Also note that you can instead require particular package version (as reported by pkg-config records). --> <use project = "czmq" libname = "libczmq" repository = "https://github.com/zeromq/czmq.git" test = "zhashx_test"> <use project = "libzmq" /> </use> <use project = "zyre" libname = "libzyre" repository = "https://github.com/zeromq/zyre.git" test = "zyre_test"> <use project = "czmq" /> </use> <use project = "malamute" libname = "libmlm" repository = "https://github.com/zeromq/malamute.git" header = "malamute.h" prefix = "mlm" test = "mlm_server_test"> <use project = "libzmq" /> <use project = "czmq" /> </use> <use project = "gsl" libname = "" repository = "https://github.com/imatix/gsl.git" debian_name = "generator-scripting-language" redhat_name = "generator-scripting-language"> </use> <!-- Edgenet Projects --> <use project = "drops" libname = "libdrops" repository = "https://github.com/edgenet/drops.git" test = "drops_test"> <use project = "czmq" /> <use project = "zyre" /> </use> <use project = "hydra" libname = "libhydra" repository = "https://github.com/edgenet/hydra.git" test = "hydra_server_test"> <use project = "czmq" /> </use> <!-- Various known third-party projects (If you're unsure of where a project belongs, add it here) --> <use project = "libsodium" prefix = "sodium" repository = "https://github.com/jedisct1/libsodium.git" release = "stable" test = "sodium_init" /> <use project = "libcurl" repository = "https://github.com/curl/curl.git" test = "curl_easy_init" header = "curl/curl.h" /> <use project = "editline" repository = "https://github.com/troglobit/editline.git" test = "readline" /> <use project = "fuse" repository = "http://git.code.sf.net/p/fuse/fuse.git" test = "fuse_main" /> <use project = "jansson" repository = "https://github.com/akheron/jansson.git" test = "json_object" /> <use project = "jemalloc" repository = "https://github.com/jemalloc/jemalloc.git" test = "malloc" header = "jemalloc/jemalloc.h" /> <use project = "msgpack" repository = "https://github.com/msgpack/msgpack-c.git" test = "msgpack_version" /> <use project = "uuid" test = "uuid_generate" header = "uuid/uuid.h" redhat_name = "libuuid-devel" debian_name = "uuid-dev" /> <use project = "asound" test = "snd_asoundlib_version" header = "alsa/asoundlib.h" /> <use project = "zdb" repository = "https://bitbucket.org/tildeslash/libzdb.git" test = "ConnectionPool_start" /> <use project = "json-c" header = "json-c/json.h" test = "json_object_to_json_string" /> <use project = "libfastjson" repository = "https://github.com/rsyslog/libfastjson/" header = "libfastjson/json.h" test = "json_object_to_json_string" /> <use project = "lognorm" repository = "https://github.com/rsyslog/liblognorm/" test = "ln_initCtx"> <use project = "libfastjson" /> </use> <use project = "zdiscgo" repository = "https://github.com/zeromq/zdiscgo.git" test = "zdiscgoplugin_new" /> <use project = "systemd" libname = "libsystemd" prefix = "libsystemd" linkname = "systemd" header = "systemd/sd-daemon.h" test = "sd_listen_fds" /> <use project = "protobuf-c" repository = "https://github.com/protobuf-c/protobuf-c/" test = "protobuf_c_version" header = "protobuf-c/protobuf-c.h"/> <!-- 42ITY project https://github.com/42ity https://42ity.org --> <use project = "fty-proto" libname = "libfty_proto" header="ftyproto.h" repository = "https://github.com/42ity/fty-proto" test = "fty_proto_test"> <use project = "libzmq"/> <use project = "czmq"/> <use project = "malamute"/> </use> <!-- OS packagers make life hard by renaming the package, binaries and even library SONAMEs - so we have to guess a bit; note that for practical purposes, lua-5.2 suffices as lua-5.1 (if fixes happen to be needed, they are trivial and googlable) --> <use project = "lua-5.1" libname = "lua" prefix="lua" optional = "0" am_lib_macro = "LUA_5_1" min_major = "5" min_minor = "1" min_patch = "0" debian_name="liblua5.1-0-dev" redhat_name="lua-devel" test = "lua_close"> <linkname>lua5.2</linkname> <linkname>lua52</linkname> <linkname>lua5.1</linkname> <linkname>lua51</linkname> <linkname>lua</linkname> <pkgconfig>lua5.2</pkgconfig> <pkgconfig>lua52</pkgconfig> <pkgconfig>lua5.1</pkgconfig> <pkgconfig>lua51</pkgconfig> <pkgconfig>lua</pkgconfig> </use> </known_projects>
Each target produces scripts and code for a specific build system, platform, or language binding.
To see a list of available targets:
gsl -target:? project.xml
To build a specific target:
gsl -target:android project.xml
To run zproject without building any targets:
gsl -target:- project.xml
To request specific targets in your project.xml file (autotools and cmake are automatic):
<target name = "android" /> <target name = "java" />
To request all targets in your project.xml file:
<target name = "*" />
A target can accept options via project.xml like this:
<project name = "..." > ... <target name = "*" /> <target name = "nuget"> <option name = "id" value = "czmq_vc120" /> <option name = "dependency"> <item name = "libzmq_vc120" value = "18.104.22.168" /> </option> </target> </project>
This generates all targets (
name = "*") and then configures the
nuget target with options. Zproject aare provided to the target handler as:
project.nuget_id = "czmq_vc120" project.nuget_dependency.name = "libzmq_vc120" project.nuget_dependency.value = "22.214.171.124"
Each target works in its own copy of 'project'. It can therefore modify and extend 'project' as wanted, without affecting other targets.
Modifying generated files in an already existent project
You may encounter a warning in a file you want to modify like this:
################################################################################ # THIS FILE IS 100% GENERATED BY ZPROJECT; DO NOT EDIT EXCEPT EXPERIMENTALLY # # Read the zproject/README.md for information about making permanent changes. # ################################################################################
If that happens, you need to follow these steps to make the modifications and then regenerate the code for czmq, malamute and zyre (all zeromq projects).
- Prior making any changes, run the script tstgenbld.sh and save its output to a log file. This will save the state of the world by regenerating several projects, building and running tests.
~/git/zproject$ ./tstgenbld.sh > ../before.log
- Search for a specific string from the file in the zproject files (use .)
- When you find it, make the modification in that file (most likely extensions will be .XML or .GSL)
- Then execute these steps in a Linux machine to regenerate all files for your project. This will build, install and run tests on them again, after your changes have been made.
~/git/zproject$ ./tstgenbld.sh > ../after.log ~/git/zproject$ meld ../after.log ../before.log
- Be aware that many files in the regenerated projects will change.
- This also means you will need to commit changes on zproject (your mods) and in czmq, malamute, zyre (the regenerated files with your mods). From git documentation, it seems like the command "git add -uv" could help to find out what files were actually modified from all the files that were regenerated. Supposedly this will only add the ones that were actually modified, but you should double check them. Make sure to double check even line termination (or use a comparisson tool that flags those differences). Windows specific files should have (CR+LF) termination, while Linux specific should have (LF) only termination. Best is to look for ".terminator=" examples in existing .GSL files.
Using an API model zproject can generate the
@interface section your class
headers. Further it allows zproject to generate various language bindings on top
of your CLASS project.
Sample API model
All API models are placed into the
api directory which resides in the root
directory of your project. For example, if your
<class name = "myclass"/>, you could create the following
<class name = "myclass"> <!-- This model defines a public API for binding. It shows a language binding developer what to expect from the API XML files. --> My Feature-Rich Class <include filename = "license.xml" /> <constant name = "default port" value = "8080">registered with IANA</constant> <constant name = "normal" value = "1" /> <constant name = "fast" value = "2" /> <constant name = "safe" value = "3" /> <!-- Constructor is optional; default one has no arguments --> <constructor> Create a new myclass with the given name. <argument name = "name" type = "string" /> </constructor> <!-- Destructor is optional; default one follows standard style --> <destructor> Destructors implicitly get a new argument prepended, which: * is called `self_p` * is of this class' type * is passed by reference * is marked as the self pointer for the destructor (`destructor_self = "1"`) </destructor> <!-- This models an CZMQ actor. By default the actor method equals the class name. --> <actor> To work with my_actor, use the CZMQ zactor API: Create new my_actor instance. zactor_t *actor = zactor_new (my_actor, NULL); Destroy my_actor instance zactor_destroy (&actor); Enable verbose logging of commands and activity: zstr_send (actor, "VERBOSE"); </actor> <!-- This models a method with no return value --> <method name = "sleep"> Put the myclass to sleep for the given number of milliseconds. No messages will be processed by it during this time. <argument name = "duration" type = "integer" /> </method> <!-- This models an accessor method --> <method name = "has feature"> Return true if the myclass has the given feature. <argument name = "feature" type = "string" /> <return type = "boolean" /> </method> <method name = "send strings"> This does something with a series of strings (until NULL). The strings won't be touched. Because the next method has the same name with a prepended "v", it's recognized as this method's `va_list` sibling (in GSL: `method.has_va_list_sibling = "1"`). This information might be used by the various language bindings. <argument name = "string" type = "string" variadic = "1" /> <return type = "boolean" /> </method> <method name = "vsend strings"> This does something with a series of strings (until NULL). The strings won't be touched (they're declared immutable by default). <argument name = "string" type = "string" variadic = "1" /> <return type = "boolean" /> </method> <!-- Callback typedefs can be declared like methods --> <callback_type name = "handler_fn"> <argument name = "self" type = "myclass" /> <argument name = "action" type = "string" /> <return type = "boolean" /> </callback_type> <!-- Callback types can be used as method arguments --> <method name = "add handler"> Store the given callback function for later <argument name = "handler" type = "my_class_handler_fn" callback = "1" /> </method> <!-- If singleton = "1", no class struct pointer is required. --> <method name = "test" singleton = "1"> Self test of this class <argument name = "verbose" type = "boolean" /> </method> <method name = "new thing" singleton = "1" > Creates a new myclass. The caller is responsible for destroying it when finished with it. <return type = "myclass" fresh = "1" /> </method> <method name = "free" singleton = "1"> Frees a provided string, and nullify the parent pointer. Setting `mutable = "1"` is not needed here, because transfering ownership from the caller to the function using `by_reference = "1"` implies that it's mutable. <argument name = "string pointer" type = "string" by_reference = "1" /> </method> <method name = "rotate" singleton = "1"> Rotates the characters in `data` in-place. This means that all characters are shifted to the left by one, removing the left-most character and appending it to the end. <argument name = "data" type = "string" mutable = "1" /> </method> <!-- These are the types we support Not all of these are supported in all language bindings; see each language binding's file for supported types in that language, and add more types as needed where appropriate. Also, see zproject_class_api.gsl to see how they're handled exactly. --> <method name = "tutorial"> <argument name = "void pointer" type = "anything" /> <argument name = "standard int" type = "integer" /> <argument name = "default float" type = "real" /> <argument name = "standard float" type = "real" size = "4" /> <argument name = "standard double" type = "real" size = "8" /> <argument name = "standard bool" type = "boolean" /> <argument name = "fixed size unsigned integer" type = "number" size = "4"> Supported sizes are 1, 2, 4, and 8. </argument> <argument name = "a byte" type = "byte" /> <argument name = "conversion mode" type = "integer" /> <argument name = "char pointer to C string" type = "string" /> <argument name = "byte pointer to buffer" type = "buffer" /> <argument name = "buffer size" type = "size" /> <argument name = "file handle" type = "FILE" /> <argument name = "file size" type = "file_size" /> <argument name = "time" type = "time" /> <argument name = "format" type = "format"> This makes the function is variadic (will cause a new argument to be added to represent the variadic arguments). </argument> <argument name = "variadic list argument" type = "va_list" /> <argument name = "custom pointer" type = "my custom class"> Any other type is valid, as long as there is a corresponding C type, in this case `my_custom_class_t`. </argument> <return type = "nothing">void method</return> </method> <method name = "set foo" polymorphic = "1"> Set attribute foo to a new value. Note that this method takes a polymorphic reference (`void *`) as its first argument, which could point to structs of different types. This also means that high-level bindings might give you the choice to call this method directly on an instance, or with an explicit receiver. <argument name = "new value" type="integer" /> </method> <method name = "set bar"> This method takes an argument type of the (descriptive) type `foo`, but resolving it to a corresponding C type will be skipped because it's overridden to `foobarbaz_t` by the `c_type` attribute. <argument name = "new foo" type="foo" c_type="foobarbaz_t" /> </method> </class>
This model will cause the following
@interface to be generated inside of
include/myclass.h. Note that if
include/myclass.h has other handwritten
content outside of the
@interface section this content will be retained. If
the header file does not exist zproject will create it.
// @warning THE FOLLOWING @INTERFACE BLOCK IS AUTO-GENERATED BY ZPROJECT! // @warning Please edit the model at "api/myclass.api" to make changes. // @interface // Create a new myclass with the given name. MYPROJECT_EXPORT myclass_t * myclass_new (const char *name); // Destroy the myclass. MYPROJECT_EXPORT void myclass_destroy (myclass_t **self_p); // Return true if the myclass has the given feature. MYPROJECT_EXPORT bool myclass_has_feature (myclass_t *self, const char *feature); // Put the myclass to sleep for the given number of milliseconds. // No messages will be processed by the actor during this time. MYPROJECT_EXPORT void myclass_sleep (myclass_t *self, int duration); // Self test of this class MYPROJECT_EXPORT void myclass_test (bool verbose); // @end
Supported API Model Attributes
The following attributes are supported for methods:
name- the name of the method (mandatory).
singleton = "1"- the method is not invoked within the context of a specific instance of an object. Use this if your method does not need to be passed a
selfpointer as the first argument as normal. Implicit for all
destructors and for the implicit
The following attributes are supported for arguments and return values:
type- the conceptual type or class name of the argument or return value (default:
"nothing", which translates to
mutable = "1"- the argument or the return value can be modified. All string, format, and buffer arguments are immutable by default.
by_reference = "1"- ownership of the argument (and responsibility for freeing it) is transferred from the caller to the function - in practice, the implementation code should also nullify the caller's reference, though this is not enforced by the API model. If a string or buffer is passed by reference, it is also mutable by default.
fresh = "1"- the return value is freshly allocated, and the caller receives ownership of the object and the responsibility for destroying it. Implies mutable = "1".
variadic = "1"- used for representing variadic arguments.
For integer arguments you can specify one or more 'map' values, which a binding target can use to generate alternative methods. For example:
<argument name = "socket type" type = "integer"> <map name = "PAIR" value = "ZMQ_PAIR" /> <map name = "PUB" value = "ZMQ_PUB" /> <map name = "SUB" value = "ZMQ_SUB" /> </argument>
The value should be a constant that the binding code has access to.
The following attributes are supported for arguments:
polymorphic- indicates that the passed class instance is a
sockishtype. For an example see CZMQ's zsock class.
This is an incomplete list of API types:
"nothing" -- for return only, means "void" in C.
"anything" -- means "void *" in C.
"size" -- long size (64 bits), "size_t" in C.
"time" -- long time (64 bits), "time_t" in C.
"msecs" -- long number of msecs, "int64_t" in C.
"file_size" -- long file size (64 bits).
"boolean" -- Boolean.
"byte" -- single octet.
"char" -- single character (possibly multibyte, do we care?)
"integer" -- 32-bit signed integer.
"number" -- unsigned number, with 'size = "1|2|4|8"'.
"real" -- single-precision floating point with 'size = "4"' (default) or double-precision with 'size = "8"'.
"buffer" -- byte array. When passing a buffer argument, if the next argument has type 'size', the binding may fill the size automatically. To return a buffer, you should specify 'size' attribute that defines how to set the buffer size. This can be a constant, 'size = "ZUUID_LEN"', or a dot followed by method name in the same class, e.g. 'size = ".size"'.
"string" -- character array.
"sockish" -- a variant socket type, may be a zsock_t, libzmq void *, or an actor handle.
"format" -- printf format, followed by zero or more arguments.
"FILE", "va_list", "zmq_pollitem", "socket" -- literally that, in C. (Not sure if it is wise to use raw C types.)
callbacks - tbd.
Names of classes, e.g. zmsg.
At any time, you can examine a resolved model as an XML string with all of its children and attributes using the appropriate GSL functions:
# if the `method` variable is a <method/> entity: echo method.string() # will print the model as an XML string. method.save(filename) # will save the model as an XML string to the given file.
You can save a snapshot of the entire resolved project model using this syntax:
gsl -save:1 project.xml
Generate API model from C header files
Writing API model for bigger project with a lot of classes can be tedious job. There mkapi.py, which automates most of the task.
In order to use it, you must install zproject itself and then pycparser. For most of real world code, you must have fake_libc_includes available too.
virtualenv/venv mkapi source mkapi/bin/activate pip install pycparser git clone https://github.com/eliben/pycparser.git
Then from root directory of your project (for example czmq), type following
mkapi.py -I /path/to/your/pycparser/utils/fake_libc_include include/czmq.h
Note you must use top-level include as pycparser fails if it does not know any definition.
The tool might expect
-DWITH_DRAFTS parameter if the class is not marked as a stable.
The tool can't distinguish methods which allocates new object. It does print a comment about adding fresh = "1" attribute to each method, which return non const pointer. However the final assigment must be done manually.
Language Binding Notes
Java Language Binding
Skips methods that it cannot handle properly.
To build, you need gradle (or equivalent). Run 'gradle build jar' in the bindings/jni directory.
- To install, run 'gradle install'. This puts the files into $HOME/.m2/repository.
Draft API Support
zproject lets you mark classes and methods as 'draft' so that they are not installed by default in stable builds. This lets you deliver draft APIs to your users, and change them later.
By default all classes and methods are draft, unless you specify otherwise. To mark the state of a class or method, specify in the project.xml:
<class name = "classname" state = "stable" />
Or in the class API XML file:
<class name = "classname" state = "stable"> ... <method name = "methodname" state = "stable"> ... </method> </class>
The method will inherit the class state unless it has its own 'state' attribute.
The allowed states are:
- draft - the class or method is not built/installed in stable releases.
- stable - the class or method is always built and installed. A method may not be changed once marked as stable.
- legacy - the class or method is always built and installed. It may carry a warning that support can be withdrawn at any time.
Using autotools or CMake, you can specify --with-drafts to enable draft APIs, and --without-drafts to disable them. By default, drafts are built and installed when you work in a git repository (if the directory ".git" is present), and otherwise they are not. That means, if you build from a tarball, drafts are disabled by default.
Installation of third party files is a hard problem. It is not platform
independent, became hard to maintain and impossible to use correctly. One of
zproject's goals is a simplicity. There is a simple installation model
- KISS, less configuration options the better
- no conditionals in the model, those SHALL be handled in background
- each option solves a REAL problem, avoid extending it because you can
<main name = "MAIN"> <install type = "systemd-tmpfiles" /> <install type = "config" name = "MAIN-ldap-integration.cfg.example" /> </main>
This will add install information about systemd tmpfiles.d configuration files
to autotools, packaging, and so. The resulting file
/usr/lib/tmpfiles.d/MAIN.conf will be installed only if configure was called
This will install additional configuration files to
Notes for Writing Targets
If you write a new target or extend one you might be in the situtation where you
need to put code fragments into files which are not specific to your target. For
systemd target has to extend files from the
redhat targets. In order to keep those files as maintainable as possible
you'll include a snippet which is pull from your targets file. To include
a snippet call:
Where target is the identifier for the insertion point i.e. the filename. To
register a snippet to be inserted simply call.
register_snippet (target, name)
Target is must match the one in
insert_snippet and the name identifies your
snippet. Then you can create a function or macro with the following form
(without the brackets):
function snippet_<target>_<name> .macro snippet_<target>_<name>
This function will be called by the
insert_snippet function. You can have an
arbitrary amount of registered snippets per insertion point which will be
inserted in arbitrary order so don't make any assumption on the order of the
snippets per insertion point.
Notes for Writing Language Targets
This is the general form of a target:
register_target ("somename", "Decription of target") function target_somename \.macro generate_something ... \.endmacro project.topdir = "someplace/somename" directory.create (project.topdir) generate_something () endfunction
classes SHALL be in the project model (
classMAY have a corresponding API model (
- A binding generator SHOULD consider only
classes with an API model (
where defined (class.api)).
- Each API model SHALL consist of both explicit information (written in the XML file) and implicit information (inferred by the
zproject_class_apiscript). Both kinds of information will already be resolved (and indistinguishable) when each language binding generator is invoked.
- Each API model SHALL have exactly one
classentity at the top level.
classSHALL have a
classMAY have one or more
classMAY have one or more
classMAY have one or more
destructorMAY have one or more
destructorSHALL at least one
returnentity, and if more than one
returnentity exist, only the first SHOULD be considered. The
returnentity MAY be ignored if it has
type = "nothing"(the default when no
- Each entity SHALL have its semantic attributes fully resolved before reaching the language binding generators.
- Each language binding generator SHALL NOT modify values of semantic attributes of entities.
- Each language binding generator MAY assign values to language-specific implementation attributes of entities.
- Each language binding generator SHOULD use a unique prefix for names of language-specific implementation attributes of entities.
class is always the top-level entity in an API model, and it will be merged with the corresponding
class entity defined in the project model. A class contains
destructors (collectively, "method"s), and methods contain
returns (collectively, "container"s). Each entity will contain both semantic attributes and language-specific implementation attributes.
Semantic attributes describe something intrinsic about the container.
For example, arguments may be described as passed
by_reference to indicate that ownership is transferred from the caller. Similarly, return values may be described as
fresh to indicate that ownership is transferred to the caller, which must destroy the object when it is finished with it. It's important to remember that these attributes are primarily meant to be an abstraction that describes conceptual information, leaving the details of how code generators interpret (or ignore) each attribute up to the authors.
Semantic attributes may be implicit (not given a value in the written model). In this case, it is up to the
zproject_class_api script to fully resolve default values for all attributes. Downstream code generators should never resolve or alter semantic attributes, as this could change the behavior of any code generator that is run after the errant code generator.
These are the semantic attributes for each kind of entity that will be resolved before language bindings generators are invoked:
class.name # string (as given in the API model) class.description # string (comment in the API model, or empty string)
method.name # string (as given in the API model, or a default value) method.description # string (comment in the API model, or a default value) method.singleton # 0/1 (default: 0, but 1 for constructors/destructors) method.is_constructor # 0/1 (default: 0, but 1 for constructors) method.is_destructor # 0/1 (default: 0, but 1 for destructors) method.has_va_list_sibling # 0/1 (default: 0)
container.name # string (as given in the API model, or "_") container.type # string (as given, or "nothing") container.mutable # 0/1 (default: 0) container.by_reference # 0/1 (default: 0) container.callback # 0/1 (default: 0) container.fresh # 0/1 (default: 0) container.variadic # 0/1 (default: 0) container.va_start # string - that holds the argment name for va_start () container.optional # 0/1 (default: 0), up to binding generator to use
Ownership and License
The contributors are listed in AUTHORS. This project uses the MPL v2 license, see LICENSE.
zproject uses the C4.1 (Collective Code Construction Contract) process for contributions.
To report an issue, use the zproject issue tracker at github.com.
Ownership and License of generated sources
The copyright of the output of zproject is by default property of the users. The license.xml file must be set up by the users to specify a license of their choosing.
Hints to Contributors
Make sure that the project model hides all details of backend scripts. For example don't make a user enter a header file because autoconf needs it.
Do read your code after you write it and ask, "Can I make this simpler?" We do use a nice minimalist and yet readable style. Learn it, adopt it, use it.
Before opening a pull request read our contribution guidelines. Thanks!
This documentation was generated from zproject/README.txt using Gitdown