6 releases
0.6.1 | Nov 2, 2020 |
---|---|
0.6.0 | Nov 2, 2020 |
0.2.0 | Mar 31, 2019 |
0.1.2 | Mar 23, 2019 |
#836 in Development tools
25 downloads per month
110KB
2.5K
SLoC
FSM generator
Installation
cargo install -f fsm_gen
You can download from repository and build and install as usual
cargo build --release
cargo install --path . -f
Versions
0.6
cpp
generated code with option to move toerror
state- Instead of
languages
, now we speak abouttemplates
0.5
- moved to tera templates
- added dot files generation
0.4
- error redefinied action on cpp (watch example iceberg)
- fix error when running on current directory
- Add full proposed file for hand written .h and .cpp on generated one
0.3
- multiline guards with no status name
- multi guard and multi actions
- '_' on input means any other input
- negative guards
- if no transition, it will generate an error
- updated rust-peg lib and working with macros
- if execption is throwed, we will go to error transition
- better error information
- on parsing show line
- check orphans status
- makefile install, test cpp
0.2
- Actions
- private hpp (hand file)
- Template functions to specialize on transaction change
- Anonymous
namespace
for functions - Add comments support on fsm grammar
TODO
-
Error transition is special
-
Inprove exceptions control
-
web ui for templates
-
read template from file
-
Update idata in order to use ispush with btrees and more
-
Complete the cpp example and update on README.md
-
Check fsm format
- detect duplicated states
- detect duplicated inputs and guards
-
output with signals
-
Add templates
Aim
All computing processes consist of receiving an input and processing it by generating an output. From the simplest to the most complex.
Sometimes, the process depends on the context and it is necessary to manage a state.
Messages and state management, therefore, are two fundamental elements of any software process.
That's why I wrote two external DSLs long time ago for both elements (which I still use in production and are a great help).
In this repository I rewrite one of them, the code generator for a state machine.
At the moment it generates C++ code (my most immediate target in production).
You can have data (fields) on inputs structs, and also on each status
To explain the system, I will use the example in cpp_test/fsm
This example is about writing a system that will handle login requests.
First the server will be asked for a password.
This key will be used to encode the username and password (this one will be passed through a hash function) in the login request.
This encoding will be irreversible (hash function). The server will perform the same operation (starting from the hash of the password) to verify the validity.
If it is OK, it will send a login confirmation.
The diagram would look like this:
A list of transitions could be written as:
// Example of fsm to manage login
// on server side
[init]
rq_key -> w_login / send_key
timer -> init
[w_login]
rq_login -> login / send_login
timer
& timeout -> error
-> w_login
[login]
rq_logout -> logout / send_logout
heartbeat -> login / update_hb
timer
& timeout -> logout
-> login
[logout]
timer -> logout
[error]
_ -> error
And this is the input for this tool to generate code
In fact, even the previous diagram has been generated from this DSL
(it generated a graphviz
dot file)
Elements
States
[init]
...
init, w_login, login ... are the states
Depending on the input and the state (with its values as will be seen later), the system will change to a new state.
Transition
rq_key -> w_login
If we receive an input (in this case rq_key
) we go to next state (w_login
)
Input
The elements received by the status machine.
INPUT
v
rq_key -> w_login
In the example they are rq_key, rq_login, rq_logout, heartbeat and timer.
Guards
Functions that will be called depending on the status and input to decide the way forward.
GUARD
v
rq_login & valid -> login / send_login
You can have more than one guard
rq_login & valid & guard2 -> login / send_login
When you apply different options guards (or combination)...
In the example we have valid, timeout, ontime.
rq_login
& valid -> login / send_login
-> logout / log_err
It could be written with negative guard
rq_login
& !valid -> logout / log_err
-> login / send_login
Final status
Behind the -> arrow is the state we will change to.
FINAL_STATUS
v
rq_key -> w_login
Actions
We can define an action to be performed when executing a transaction.
This will be after the final state and '/'.
ACTION
v
rq_login -> logout / log_err
You can have more than one action
rq_login -> logout / log_err action2
In this example we have send_key, send_login...
Special transition
In all states it is necessary to consider all inputs.
But it is very common that many transitions are the same (generally error cases).
This is marked with the input _
Consider the this example status:
[init]
rq_key -> w_login / send_key
timer -> init
_ -> logout / log_err
_ means... any other input...
Therefore considering all possible inputs in this state
error
status and implicit transitions
error
is a special status
You can move to error
status explicitly.
Any transition no defined, will finis on error status.
You can also put some verifications on transiction funcion, and incase
of fail, you can move to error (even when is not explicitly writted on fsm
)
This is so, because checking the params, is so commont that adding guards for it, would generate a lot of sound
In our example...
[init]
rq_key -> w_login / send_key
timer -> init
There are no transations for rq_login
and rq_logout
. Both are implicit and is
equivalent to...
[init]
rq_key -> w_login / send_key
timer -> init
_ -> error
This is the transition function control (obiosly you can specialize as you wish)
// status change functions
template <typename FROM, typename IN, typename TO>
std::variant<TO, st_error_t> fromin2(const FROM &, const IN &) {
// here you could check the params and decide to go to error
// instead to the programmed trasnsition
...
}
And this is when you explicitly write a transition who finished on error status
template <typename FROM, typename IN>
st_error_t fromin2error(const FROM &, const IN &) {
return st_error_t{...};
}
Another way to end on error transition. If an exception is thrown while the input is being procesed...
[...]
} catch (...) {}
auto nw_st_info = fromin2error<st_init_t, in_rq_key_t>(this->info, in);
log("[init] rq_key error/default -> error", in, info, nw_st_info);
return std::make_shared<error>(nw_st_info);
Comments
Comments starts at //
and continues to the end of line
Usage
To get help...
fsm_gen --help
> fsm_gen -h
fsm_gen 0.6.1
jleahred
Generate code from a simple fsm file
To check the supported templates --show_templs
USAGE:
fsm_gen [FLAGS] [OPTIONS] [fsm_files]...
FLAGS:
-d, --dot-graphviz Generate graphviz dot file
-h, --help Prints help information
--help-cpp Give me some information about generating cpp files
-s, --show-templs Show supported template generators
-V, --version Prints version information
OPTIONS:
-T, --threads <n_threads> Number of threads to use. 0 means one per core ;-) [default: 0]
-t, --templ <templ> Template to generate code (show available --show-templs) [default: cpp]
ARGS:
<fsm_files>... List of fsm files to be processed
The default template is c++
(and at the moment the only one)
You can run:
fsm_gen login.fsm
And it will generate the c++
You can pass a list of fsm
files
fsm_gen login.fsm test/seller.fsm test/test2/lift.fsm
The code will be generated on same directory of original .fsm
file
If your shell supports it, you could run...
fsm_gen **/*.fsm
C++ code generation
Starting from the example login.fsm
the system will create...
fsm_login_gen.h
fsm_login_gen.cpp
You don't have to modify these files.
You have to write your code on next files...
fsm_login_types.h
fsm_login_private.hpp
These two files will be created if don't exist as a reference
A empty reference code for these two files will be added on _gen
files as comments.
Files dependency:
fsm_login_gen.h
Full code on cpp_test/fsm/fsm_login_gen.h
We are informed on when it was created.
This file is the starting point to use or extend the generated status machine in your program.
// generated automatically 2019-03-22 11:24:40
// do not modify it manually
Headers and namespaces
based on filename
#pragma once
#include <iostream>
#include <memory>
namespace login {
Internal class forward declaration
class BaseState;
typedef std::shared_ptr<BaseState> SState;
The fsm
class you have to instantiate or extend
// -------------------
// F S M
class Fsm {
public:
Fsm();
~Fsm();
void process(const heartbeat_t& in);
void process(const rq_key_t& in);
void process(const rq_login_t& in);
void process(const rq_logout_t& in);
void process(const timer_t& in);
...
}
fsm_login_gen.cpp
Full code on cpp_test/fsm/fsm_login_gen.cpp
You must not modify this file, and it's not necessary to know much about it
fsm_login_types.h
Full code on cpp_test/fsm/fsm_login_types.h
In this file you have to declare the status info types, and input types
If the file doesn't exist, it will be created with empty data types
// Code generated automatically to be filled manually
// This file will not be updated by generator
// It's created just the first time as a reference
// Generator will allways create a .reference file to help with
// new methods and so
On namespace
based on fsm file, we have the two types to declare
You can, of course, complete these types on cpp file if necessary
namespace login {
// status info types
struct st_init_t{};
struct st_w_login_t{};
struct st_login_t{};
struct st_logout_t{};
struct st_error_t{};
// input types
struct in_heartbeat_t {};
struct in_rq_key_t {};
struct in_rq_login_t {};
struct in_rq_logout_t {};
struct in_timer_t {};
} // namespace login
#endif // FSM_LOGIN_H
fsm_login_private.hpp
Full code on cpp_test/fsm/fsm_login_private.hpp
This is the other file you have to maintain by hand.
// Code generated automatically to be filled manually
// This file will not be updated by generator
// It's created just the first time as a reference
// Generator will allways create a .reference file to help with
// new methods and so
// This file will be included in _gen.cpp
// (anywhere else)
// to make happy some IDEs
#include "fsm_login_types.h"
#include "fsm_login_gen.h"
namespace {
using namespace login;
As you can see, it is on anonymous namespace
.
This file is private, it will be included by _gen.cpp
. Defining an anonymous
namespace
, we keep this implementation as private. Even more important, the compiler
will alert us if we forget an implementation, also if one is not necessary.
Log and status change transitions are templates.
This is a log example:
[init] rq_key -> w_login
[w_login] rq_login(valid) -> login
[login] rq_logout -> logout
In this way, you can specialize or generalize as much as you want.
// log
template <typename IN, typename INIT_ST, typename END_ST>
void log(const std::string &txt_trans, const IN &, const INIT_ST &,
const END_ST &) {
std::cout << txt_trans << std::endl;
}
// status change functions
template <typename FROM, typename IN, typename TO>
std::variant<TO, st_error_t> fromin2(const FROM &, const IN &) {
// you can specialize this generic function
return TO{};
}
template <typename FROM, typename IN>
st_error_t fromin2error(const FROM &, const IN &) {
return st_error_t{};
}
First parameter in log, is an string with transition change information (initial transition, input, guard if so, final transition)
Next, we have the guards and actions functions.
// guards
bool valid(const in_rq_login_t& /*in*/, const st_w_login_t& /*st_info*/) { return true; }
bool timeout(const in_timer_t& /*in*/, const st_w_login_t& /*st_info*/) { return true; }
bool timeout(const in_timer_t& /*in*/, const st_login_t& /*st_info*/) { return true; }
// actions
void act_send_key(const st_init_t& /*st_orig*/, const in_rq_key_t& /*in*/, const st_w_login_t& /*st_dest*/) {}
void act_send_login(const st_w_login_t& /*st_orig*/, const in_rq_login_t& /*in*/, const st_login_t& /*st_dest*/) {}
void act_send_logout(const st_login_t& /*st_orig*/, const in_rq_logout_t& /*in*/, const st_logout_t& /*st_dest*/) {}
void act_update_hb(const st_login_t& /*st_orig*/, const in_heartbeat_t& /*in*/, const st_login_t& /*st_dest*/) {}
} // namespace anonymous
Diagrams source
digraph G {
rankdir = BT;
node [shape=plaintext fontname="Arial"];
main -> "fsm_login_gen.h"
"fsm_login_gen.cpp" -> "fsm_login_gen.h"
"fsm_login_gen.h" -> "fsm_login_types.h"
}
Dependencies
~11–20MB
~276K SLoC