started state machine extraction tool

docs/StateMachineExtraction.txt

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+
+Project title: "Annotation-based state machine definition for doubly nested switch-case implementations"
+
+- goals: testability, documentation
+- assumptions: fixed code stucture
+- input: some code (.c)
+- output: graphviz state machine ...
+- documentation: BTstack Wiki page
+- implementation: Python
+- problems: 
+  - implicit event like "can send packet now", =? deal with guards?
+  - "inverse handler" for "global" events
+
+Example:
+{
+    // @STATEMACHINE(multiplexer)
+    switch (multiplexer->state) {       // detect state variable, count {
+        case W4_MULTIPLEXER:            // implicit state
+            switch (event) {            // events start here
+                case  L2CAP_OPEN:       // implicit event
+                    // @ACTION(action description)
+                    multiplexer->state = OTHER_STATE;
+                    break;              // break || return -> end case block
+            }
+            break;
+        case OTHER_STATE:
+            break;
+        }
+    }
+}
+    

docs/extract.py

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+#!/usr/bin/env python
+
+import re
+
+class Transition(object):
+    def __init__ (self, fromState, toState, event, guard, action):
+        self.fromState   = fromState
+        self.toState     = toState
+        self.event  = event
+        self.guard  = guard
+        self.action = action
+
+statemachineName = ""
+stateVariable = ""
+numBraces = 0
+fromState = ""
+toState = ""
+onEvent = ""
+action = ""
+
+def parseLine(line):
+    global statemachineName
+    global numBraces
+    global stateVariable
+    global fromState
+    global toState
+    global onEvent
+    global action
+    
+    # looks for annotations
+    ann = re.compile("(@\w*)\s*(\((.*)\))?")
+    anns = ann.findall(line)
+    if anns:
+        if "@STATEMACHINE" in anns[0]:
+            # print "statemachine, name:", anns[0][2]
+            statemachineName = anns[0][2]
+            numBraces = 0
+            stateVariable = ""
+        if "@ACTION" in anns[0]:
+            action = anns[0][2]
+                        
+    # look for switch
+    switch = re.compile("(switch)\s*\(\s*(.*)\s*\)")
+    switches = switch.findall(line)
+    if (switches):
+        if numBraces == 0:
+            stateVariable = switches[0][1]
+            # print "switch on state opened", numBraces, stateVariable
+        # if numBraces == 1:
+            # print "switch on event opened", numBraces
+        
+    # count curly braces when inside statemachine
+    if statemachineName:
+        for c in line:
+            before = numBraces
+            if '{' in c:
+                numBraces = numBraces + 1
+            if '}' in c:
+                numBraces = numBraces - 1            
+            
+    # look for case
+    case = re.compile("(case)\s*(.*):")
+    cases = case.findall(line)
+    if cases:
+        if numBraces == 1:
+            # print "from state: " + cases[0][1]
+            fromState = cases[0][1]
+        if numBraces == 2:
+            # print "on event: " + cases[0][1]
+            onEvent = cases[0][1]
+            toState = ""
+            action = ""
+            
+    # look for break or return
+    brk = re.compile("(break)")
+    breaks = brk.findall(line)
+    rtrn = re.compile("(return)")
+    returns = rtrn.findall(line)
+    if numBraces > 1:
+        if breaks or returns:
+            if not toState:
+                toState = fromState
+            # print "to state:", toState
+            print fromState + "->" + toState + " [label=\"" + onEvent + "/" + action + "\"];"
+    
+    # look for state transition
+    if stateVariable:
+        stateTransition = re.compile( stateVariable + "\s*=\s*(.*);")
+        transition = stateTransition.findall(line)
+        if transition:
+            toState = transition[0]
+    
+
+def parseFile(filename):
+    f = open (filename, "r")
+    for line in f:
+        parseLine(line)
+    f.close()
+
+print "digraph fsm { "
+print "size = \"8.5\""
+parseFile("/Projects/iPhone/btstack/src/l2cap.c")
+print "}"
+

docs/lamp.c

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+#include <stdio.h>
+
+typedef enum {
+    LAMP_OFF = 1,
+    LAMP_ON
+} state_t;
+
+typedef enum {
+    TOGGLE_ON = 1,
+    TOGGLE_OFF
+} event_t;
+
+state_t state;
+
+void statemachine(event_t ev){
+
+    printf("State: %u, event: %u\n", state, ev);
+
+    // @STATEMACHINE(lamp)    
+    switch(state){
+        case LAMP_OFF:
+            switch(ev){
+                case TOGGLE_ON:
+                    // @ACTION(Turning lamp on)
+                    printf("Turning lamp on\n");
+                    state = LAMP_ON;
+                    break;
+                case TOGGLE_OFF:
+                    // @ACTION(Ignoring toggle off)
+                    printf("Ignoring toggle off\n");
+                    break;
+            }
+            break;
+        case LAMP_ON:
+            switch(ev){
+                case TOGGLE_ON:
+                    // @ACTION(Ignoring toggle on)
+                    printf("Ignoring toggle on\n");
+                    break;
+                case TOGGLE_OFF:
+                    // @ACTION(Turning lamp off)
+                    printf("Turning lamp off\n");
+                    state = LAMP_OFF;
+                    break;
+            }
+    }    
+}
+
+int main(void){
+    state = LAMP_OFF;
+    statemachine( TOGGLE_ON );
+    statemachine( TOGGLE_ON );
+    statemachine( TOGGLE_OFF );
+}